We all work in with distributed systems, independent of scale.
Failures will happen, no matter what you do, so learn how to deal with them while still being available most of the time.
ACID (Atomicity, Consistency, Isolation, Durability) level guarantees for the inclusions and updates to the data.
Some data can always be accessed.
The system continues to function even if parts of it can't communicate between each other.
You have to pick 2 and work around the other.
Most distributed databases. MongoDB, ElasticSearch, Redis and others, all fall into this category. If you get a network partition, the smaller side of the partition stops working as it won't be able to elect a master. Or you get a split-brain. And then you're DOOMED.
The system goes into a read-only (or unavailable) mode to prevent inconsistencies until the partition heals.
The way most caches work (like Memcached or Redis) or distributed message queues (like Amazon SQS). Consistency is not guaranteed but it will usually provide an answer (maybe old or incomplete) even during partition events.
AP systems are the most common solution for actual distributed systems as downtime is not acceptable and failures will happen (and cause partitions) all the time. Consistency is the most common victim of distributed systems.
The meat
The probability of completing a request. How many 9's of availability can your system provide?

Define your systems in terms of how you can degrade harvest or yield to fit it's usage and your customer's needs.
Check http://tinyurl.com/yjxzqlk for a full Farmville writeup.
Is it better to show some search results or none?
There is always a > 0% chance that something is broken since the network is based on best effort delivery.
What are your data hot spots? Can you replicate them to provide better harvest? Can you distribute your replicas across availability zones so that one zone failing does not reduce harvest drastically?
Yes, microservices! Buzzword bingo!
This is a 1999 paper and they already knew this and you're still asking yourself if you should use them or not.
Push complexity to where it actually needs to live. One piece of the app can live as an AP system with an expiration based cache? Then build it like that!
Failure detection and restarts? Make it orthogonal. Service discovery? Make it orthogonal. Load balancing? Make it orthogonal.
Running on AWS with Elastic Load Balancer, Auto-Scaling groups, health checks and auto-termination? You might be already doing this!
Even systems that were not originally made to be reliable can be made scalable by placing a "reliable" interface on top of them that provides these characteristics, like Netflix's Hystrix.
Since it's publication in 1999, many of the services touted here have been implemented in what we now call the cloud, using these concepts of orthogonality and building blocks to get applications to be distributed.
Unfortunately, some of the calls for research here are still unanswered for, specially the programming model that provides first-class abstractions for manupulating degraded results. So far, most of the solutions have been ad-hoc and application specific.


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Women 'better drivers than men and break road laws less often'
Research by confused.com shows that although women are more likely to fail their test first time but once they're on the road they're better than men
by Tom Davidson, https://www.mirror.co.uk/authors/tom-davidson/Women are better drivers than men and break road laws less often, according to new research.
The fairer sex may be more likely to fail their test first time but once they're on the road they're better than men.
Confused.com found that when it comes to breaking the law on the road men outnumber women almost four to one with less than one per cent of women convicted of careless driving compared to two per cent of men.
And just 1% have been caught drink-driving compared to 5% of men.
Of the 600,000 motoring offences committed in England and Wales last year, 79% of them were committed by men.
According to road safety charity Brake in the UK, 80% of men and 67% of women have a valid driving licence.
When it comes to the most common offences, men dominate, the research shows.
There were 1.4 million insurance claims in 2018 and it is men who are twice as likely to make an insurance claim than women are.
The study found that they are also more likely to be “at fault” than women are when making a claim.
Historically, women also pay less for their car insurance than men and this is because they are seen to be statistically safer drivers.


First page Back Continue Last page Overview Graphics
forGL Goals
Anyone that can type on a computer*
can learn computer programming**.
Computer programming experience
or even English*** is not needed.
* Such as: Phones, Tablets, Laptops, Consoles, Desktops…
** Languages: Haxe, Haxe output languages, forGL itself...
*** Concept proved. More Internationalization work to do!
forGL is not a programming language but may act like one


Stripped Bare Media is a digital product & web development studio based in Oulu, Finland. Our studio is currently on an extended hiatus, but we'll be back ;)Juha Liikala is the founder of Stripped Bare Media.
© 2013 - 2021 Stripped Bare MediaContact Us


-
Disqus running and other good news!

Jekyll Jekyll Hyde Jekyll Hyde Hyde Jekyll (where is that from?)
-
Time to start a blog!
What should I build?
-
Testing this
Time to get a blog started


Source code for domonic.constants.keyboard
"""
domonic.constants.keyboard
====================================
"""
[docs]class KeyCode():
A = '65' #:
ALTERNATE = '18' #:
B = '66' #:
BACKQUOTE = '192' #:
BACKSLASH = '220' #:
BACKSPACE = '8' #:
C = '67' #:
CAPS_LOCK = '20' #:
COMMA = '188' #:
COMMAND = '15' #:
CONTROL = '17' #:
D = '68' #:
DELETE = '46' #:
DOWN = '40' #:
E = '69' #:
END = '35' #:
ENTER = '13' #:
RETURN = '13' #:
EQUAL = '187' #:
ESCAPE = '27' #:
F = '70' #:
F1 = '112' #:
F10 = '121' #:
F11 = '122' #:
F12 = '123' #:
F13 = '124' #:
F14 = '125' #:
F15 = '126' #:
F2 = '113' #:
F3 = '114' #:
F4 = '115' #:
F5 = '116' #:
F6 = '117' #:
F7 = '118' #:
F8 = '119' #:
F9 = '120' #:
G = '71' #:
H = '72' #:
HOME = '36' #:
I = '73' #:
INSERT = '45' #:
J = '74' #:
K = '75' #:
L = '76' #:
LEFT = '37' #:
LEFTBRACKET = '219' #:
M = '77' #:
MINUS = '189' #:
N = '78' #:
NUMBER_0 = '48' #:
NUMBER_1 = '49' #:
NUMBER_2 = '50' #:
NUMBER_3 = '51' #:
NUMBER_4 = '52' #:
NUMBER_5 = '53' #:
NUMBER_6 = '54' #:
NUMBER_7 = '55' #:
NUMBER_8 = '56' #:
NUMBER_9 = '57' #:
NUMPAD = '21' #:
NUMPAD_0 = '96' #:
NUMPAD_1 = '97' #:
NUMPAD_2 = '98' #:
NUMPAD_3 = '99' #:
NUMPAD_4 = '100' #:
NUMPAD_5 = '101' #:
NUMPAD_6 = '102' #:
NUMPAD_7 = '103' #:
NUMPAD_8 = '104' #:
NUMPAD_9 = '105' #:
NUMPAD_ADD = '107' #:
NUMPAD_DECIMAL = '110' #:
NUMPAD_DIVIDE = '111' #:
NUMPAD_ENTER = '108' #:
NUMPAD_MULTIPLY = '106' #:
NUMPAD_SUBTRACT = '109' #:
O = '79' #:
P = '80' #:
PAGE_DOWN = '34' #:
PAGE_UP = '33' #:
PERIOD = '190' #:
Q = '81' #:
QUOTE = '222' #:
R = '82' #:
RIGHT = '39' #:
RIGHTBRACKET = '221' #:
S = '83' #:
SEMICOLON = '186' #:
SHIFT = '16' #: ?? left or right or both?
SLASH = '191' #:
SPACE = '32' #:
T = '84' #:
TAB = '9' #:
U = '85' #:
UP = '38' #:
V = '86' #:
W = '87' #:
X = '88' #:
Y = '89' #:
Z = '9' #:
# TODO - do the modifiers
# find attribute by value
# def get_letter(self, attr):
# for key, value in self.__dict__.iteritems():
# if value == attr:
# return key
# return None
def __init__(self):
""" constructor for the keyboard class """
pass


Decision on six bus companies in Dhaka by March, says Mayor Khokon
by bdnews24.comDhaka South Mayor Sayeed Khokon says a decision could be made by March to bring the buses operating in Dhaka under six companies as part of an effort to discipline public transports.
“We hope we can make a decision by March to operate buses on 22 routes under six companies in Dhaka. We will be able to run experimental bus services in March.”
Discipline in public transports will be visible in March, Mayor Khokon said at a meeting at the Nagar Bhaban on Monday.
“A meeting will be held with Dhaka’s bus company owners at the end of this month. A decision on bus route franchising will be made in the meeting.”
A bus service from Sadarghat to Rampura via Demra will be launched in the last week of December, Khokon said.


Start Bootstrap
Web Developer - Graphic Artist - User Experience Designer
Portfolio
About
Freelancer is a free bootstrap theme created by Start Bootstrap. The download includes the complete source files including HTML, CSS, and JavaScript as well as optional LESS stylesheets for easy customization.
Contact Me
Project Title
Use this area of the page to describe your project. The icon above is part of a free icon set by
Flat Icons
. On their website, you can download their free set with 16 icons, or you can purchase the entire set with 146 icons for only $12!


Dont know what to try? Drop has you covered with its script hub with dfferent usefull scripts to try from like : Trolling FE script, Autofarmers, or Kill all scripts!
Drop wants to make everyones exploiting easier, so we made the UI user frienldy for any person, that wants to start exploiting or has experience already.


Scribbling signature pad is not at all different from writing on an image, which we all do regularly in our Whatsapp, Facebook etc. image shares. Essentially, we create a Canvas in the app, and let the user draw on the Canvas.


There is a full assembler available when needed, it can be accessed using two ways.
A simple assembler statement consists of the token "asm"
followed
by a single assembler statement.
Example:
asm clrwdt -- single assembler statement
A full assembler statement consists of the token "assembler"
,
a sequence of label declarations, labels and assembler statements,
and is terminated with the token token "end assembler"
.
ASSEMBLER [LOCAL label[, label2...]] [label:] [ { BANK | PAGE } ] asm statement ... END ASSEMBLER
Any labels used as the destination of a CALL or GOTO must be defined in the LOCAL clause.
If the assembler statement accesses a file register and the BANK mnemonic is used, the appropriate statements will be generated to guarantee the correct data bank is accessed.
Example:
asm bank clrf myvar ; will set the correct bank of "myvar"
If the assembler statement jumps to a label and the PAGE mnemonic is used, the appropriate statements will be generated to guarantee the correct code segment is used.
Example:
asm page goto mylabel ; will set the correct page of "mylabel"
The full list of assembly statements defined in the PIC16F877/88 data sheet have been implemented using the syntax found therein.
| f | Register file address (0x00 to 0x7F) |
| w | Working register (accumulator) |
| b | Bit address within an 8 bit file register |
| k | Literal field |
| d |
Destination select:
d=w: store result in W, d=f: store result in f, default d=f |
| Mnemonic | Description | Cycles | Flags affected |
|---|---|---|---|
| Byte-oriented file register operations | |||
| ADDWF f,d | add W and f | 1 | C,DC,Z |
| ANDWF f,d | AND W and f | 1 | Z |
| CLRF f | Clear f | 1 | Z |
| CLRW | Clear W | 1 | Z |
| COMF f,d | Complement f | 1 | Z |
| DECF f,d | Decrement f | 1 | Z |
| DECFSZ f,d | Decrement f, skip if 0 | 1(2) | |
| INCF f,d | Increment f | 1 | Z |
| INCFSZ f,d | Increment f, skip if 0 | 1(2) | |
| IORWF f,d | Inclusive OR W with f | 1 | Z |
| MOVF f,d | Move f | 1 | Z |
| MOVWF f | Move W to f | 1 | |
| NOP | No operation | 1 | |
| RLF f,d | Rotate left f through carry | 1 | C |
| RRF f,d | Rotate right f through carry | 1 | C |
| SUBWF f,d | Subtract W from f | 1 | C,DC,Z |
| SWAPF f,d | Swap nibbles in f | 1 | |
| XORWF f,d | Exclusive OR W with f | 1 | Z |
| Bit-oriented file register operations | |||
| BCF f,b | Bir clear f | 1 | |
| BSF f,b | Bit set f | 1 | |
| BTFSC f,b | Bit test f, skip if clear | 1(2) | |
| BTFSS f,b | Bit test f, skip if set | 1(2) | |
| Literal and control operations | |||
| ADDLW k | Add literal and W | C,DC,Z | |
| ANDLW k | AND literal with W | Z | |
| CALL k | Call subroutine | ||
| CLRWDT | Clear watchdog timer | !TO,!PD | |
| GOTO k | Go to address | ||
| IORLW k | Inclusive OR literal with W | Z | |
| MOVLW k | Move literal to W | ||
| RETFIE | Return from interrupt | ||
| RETLW k | Return with literal in W | ||
| RETURN | Return from subroutine | ||
| SLEEP | Go into standby mode | !TO,!PD | |
| SUBLW k | Subtract W from literal | C,DC,Z | |
| XORLW k | Exclusive OR literal with W | Z | |
| Macros and extra mnemonics | |||
| OPTION k | Move literal to OPTION register | 1 | |
| TRIS {5,6,7} | Move W to TRIS {5,6,7} register | 1 | |
| MOVFW f | A synonym for MOVF f, W | 1 | Z |
| SKPC | A synonym for BTFSS _status, _c | 1(2) | |
| SKPNC | A synonym for BTFSC _status, _c | 1(2) | |
| SKPZ | A synonym for BTFSS _status, _z | 1(2) | |
| SKPNZ | A synonym for BTFSC _status, _z | 1(2) | |
An assembly statement can access any variable in scope. Only the simple types BIT, BYTE, SBYTE and ARRAY are supported.
If the variable is a table, you must take care of:
movf x[3],w
movlw x[3]
movf x[3],w
var byte x[]="hello" var bit cc = low var byte a assembler local 10: movf x[3],w movwf a btfss cc goto 10 incf a,f 10: nop end assembler


While watching Men in Black 2 a few months back I saw an actor who I recognized not by name, but from the Fox comedy Brooklyn Nine Nine. While I could have just gone to IMDB and seek out the common name of my mystery actor I was inspired to write this small application. With it, one can search up to 6 movies or television shows and have a beautiful venn diagram generated showing similar actors between the search items. The Movie Database API is used to search for actors by movie. The jVenn jQuery Plugin is used to generate the venn diagrams.


Type Definitions
The following type definitions are available globally.
-
A notification indicating that changes were made to a Realm.
Declaration
Objective-C
typedef NSString *RLMNotification
Swift
struct RLMNotification : _ObjectiveCBridgeable, Hashable, Equatable, _SwiftNewtypeWrapper, RawRepresentable
-
A block type which provides both the old and new versions of an object in the Realm. Object properties can only be accessed using keyed subscripting.
Declaration
Parameters
oldObject
The object from the original Realm (read-only).
newObject
The object from the migrated Realm (read-write).
-
A callback block for
RLMObject
notifications.If the object is deleted from the managing Realm, the block is called with
deleted
set toYES
and the other two arguments arenil
. The block will never be called again after this.If the object is modified, the block will be called with
deleted
set toNO
, anil
error, and an array ofRLMPropertyChange
objects which indicate which properties of the objects were modified.If an error occurs,
deleted
will beNO
,changes
will benil
, anderror
will include information about the error. The block will never be called again after an error occurs.Declaration
Objective-C
typedef void (^RLMObjectChangeBlock)(BOOL, NSArray<RLMPropertyChange *> *_Nullable, NSError *_Nullable)
Swift
typealias RLMObjectChangeBlock = (Bool, [RLMPropertyChange]?, Error?) -> Void
-
A callback used to vend the results of a partial sync fetch.
Declaration
Objective-C
typedef void (^RLMPartialSyncFetchCallback)(RLMResults *_Nullable, NSError *_Nullable)
Swift
typealias RLMPartialSyncFetchCallback = (RLMResults?, Error?) -> Void
-
The type of a block to run whenever the data within the Realm is modified.
Declaration
Objective-C
typedef void (^RLMNotificationBlock)(RLMNotification _Nonnull, RLMRealm *_Nonnull)
Swift
typealias RLMNotificationBlock = (RLMNotification, RLMRealm) -> Void
-
The type of a migration block used to migrate a Realm.
Declaration
Objective-C
typedef void (^RLMMigrationBlock)(RLMMigration *_Nonnull, uint64_t)
Swift
typealias RLMMigrationBlock = (RLMMigration, UInt64) -> Void
Parameters
migration
A
RLMMigration
object used to perform the migration. The migration object allows you to enumerate and alter any existing objects which require migration.oldSchemaVersion
The schema version of the Realm being migrated.
-
A block called when opening a Realm for the first time during the life of a process to determine if it should be compacted before being returned to the user. It is passed the total file size (data + free space) and the total bytes used by data in the file.
Return
YES
to indicate that an attempt to compact the file should be made. The compaction will be skipped if another process is accessing it.Declaration
Objective-C
typedef BOOL (^RLMShouldCompactOnLaunchBlock)(NSUInteger, NSUInteger)
Swift
typealias RLMShouldCompactOnLaunchBlock = (UInt, UInt) -> Bool
-
A token representing an identity provider’s credentials.
Declaration
Objective-C
typedef NSString *RLMSyncCredentialsToken
Swift
typealias RLMSyncCredentialsToken = NSString
-
A type representing the unique identifier of a Realm Object Server identity provider.
Declaration
Objective-C
typedef NSString *RLMIdentityProvider
Swift
struct RLMIdentityProvider : _ObjectiveCBridgeable, Hashable, Equatable, _SwiftNewtypeWrapper, RawRepresentable
-
A block type representing a block which can be used to report a sync-related error to the application. If the error pertains to a specific session, that session will also be passed into the block.
Declaration
Objective-C
typedef void (^RLMSyncErrorReportingBlock)(NSError *_Nonnull, RLMSyncSession *_Nullable)
Swift
typealias RLMSyncErrorReportingBlock = (Error, RLMSyncSession?) -> Void
-
A property on which a
RLMResults<RLMSyncPermission *>
can be queried or filtered.Warning
If buildingNSPredicate
s using format strings including these string constants, use %K instead of %@ as the substitution parameter.Declaration
Objective-C
typedef NSString *RLMSyncPermissionSortProperty
Swift
struct RLMSyncPermissionSortProperty : _ObjectiveCBridgeable, Hashable, Equatable, _SwiftNewtypeWrapper, RawRepresentable
-
The type of a progress notification block intended for reporting a session’s network activity to the user.
transferredBytes
refers to the number of bytes that have been uploaded or downloaded.transferrableBytes
refers to the total number of bytes transferred, and pending transfer.Declaration
Objective-C
typedef void (^RLMProgressNotificationBlock)(NSUInteger, NSUInteger)
Swift
typealias RLMProgressNotificationBlock = (UInt, UInt) -> Void
-
A block type used for APIs which asynchronously vend an
RLMSyncUser
.Declaration
Objective-C
typedef void (^RLMUserCompletionBlock)(RLMSyncUser *_Nullable, NSError *_Nullable)
Swift
typealias RLMUserCompletionBlock = (RLMSyncUser?, Error?) -> Void
-
A block type used to report the status of a password change operation. If the
NSError
argument is nil, the operation succeeded.Declaration
Objective-C
typedef void (^RLMPasswordChangeStatusBlock)(NSError *_Nullable)
Swift
typealias RLMPasswordChangeStatusBlock = (Error?) -> Void
-
A block type used to report the status of a permission apply or revoke operation. If the
NSError
argument is nil, the operation succeeded.Declaration
Objective-C
typedef void (^RLMPermissionStatusBlock)(NSError *_Nullable)
Swift
typealias RLMPermissionStatusBlock = (Error?) -> Void
-
A block type used to report the status of a permission offer operation.
Declaration
Objective-C
typedef void (^RLMPermissionOfferStatusBlock)(NSString *_Nullable, NSError *_Nullable)
Swift
typealias RLMPermissionOfferStatusBlock = (String?, Error?) -> Void
-
A block type used to report the status of a permission offer response operation.
Declaration
Objective-C
typedef void (^RLMPermissionOfferResponseStatusBlock)(NSURL *_Nullable, NSError *_Nullable)
Swift
typealias RLMPermissionOfferResponseStatusBlock = (URL?, Error?) -> Void
-
A block type used to asynchronously report results of a permissions get operation. Exactly one of the two arguments will be populated.
Declaration
Objective-C
typedef void (^RLMPermissionResultsBlock)( RLMResults<RLMSyncPermission *> *_Nullable, NSError *_Nullable)
Swift
typealias RLMPermissionResultsBlock = (RLMResults<RLMSyncPermission>?, Error?) -> Void
-
A block type used to asynchronously report results of a user info retrieval. Exactly one of the two arguments will be populated.
Declaration
Objective-C
typedef void (^RLMRetrieveUserBlock)(RLMSyncUserInfo *_Nullable, NSError *_Nullable)
Swift
typealias RLMRetrieveUserBlock = (RLMSyncUserInfo?, Error?) -> Void
-
A block type used to report an error related to a specific user.
Declaration
Objective-C
typedef void (^RLMUserErrorReportingBlock)(RLMSyncUser *_Nonnull, NSError *_Nonnull)
Swift
typealias RLMUserErrorReportingBlock = (RLMSyncUser, Error) -> Void
-
A token originating from the Realm Object Server.
Declaration
Objective-C
typedef NSString *RLMServerToken
Swift
typealias RLMServerToken = NSString


- addCustomProperty(String, Object) - 类 中的方法com.relayrides.pushy.apns.util.ApnsPayloadBuilder
-
Adds a custom property to the payload.
- ALTERNATE_APNS_PORT - 类 中的静态变量com.relayrides.pushy.apns.ApnsClient
-
An alternative port for communication with the APNs gateway.
- ApnsClient<T extends ApnsPushNotification> - com.relayrides.pushy.apns中的类
-
An APNs client sends push notifications to the APNs gateway.
- ApnsClient(File, String) - 类 的构造器com.relayrides.pushy.apns.ApnsClient
-
Creates a new APNs client that will identify itself to the APNs gateway with the certificate and key from the
given PKCS#12 file.
- ApnsClient(File, String, EventLoopGroup) - 类 的构造器com.relayrides.pushy.apns.ApnsClient
-
Creates a new APNs client that will identify itself to the APNs gateway with the certificate and key from the
given PKCS#12 file.
- ApnsClient(InputStream, String) - 类 的构造器com.relayrides.pushy.apns.ApnsClient
-
Creates a new APNs client that will identify itself to the APNs gateway with the certificate and key from the
given PKCS#12 input stream.
- ApnsClient(InputStream, String, EventLoopGroup) - 类 的构造器com.relayrides.pushy.apns.ApnsClient
-
Creates a new APNs client that will identify itself to the APNs gateway with the certificate and key from the
given PKCS#12 input stream.
- ApnsClient(X509Certificate, PrivateKey, String) - 类 的构造器com.relayrides.pushy.apns.ApnsClient
-
Creates a new APNs client that will identify itself to the APNs gateway with the given certificate and
key.
- ApnsClient(X509Certificate, PrivateKey, String, EventLoopGroup) - 类 的构造器com.relayrides.pushy.apns.ApnsClient
-
Creates a new APNs client that will identify itself to the APNs gateway with the given certificate and
key.
- ApnsClientMetricsListener - com.relayrides.pushy.apns中的接口
-
A metrics listener receives events from an
ApnsClient
that can be used to measure the performance and
behavior of the client.
- ApnsPayloadBuilder - com.relayrides.pushy.apns.util中的类
-
A utility class for constructing JSON payloads suitable for inclusion in APNs push notifications.
- ApnsPayloadBuilder() - 类 的构造器com.relayrides.pushy.apns.util.ApnsPayloadBuilder
-
Constructs a new payload builder.
- ApnsPushNotification - com.relayrides.pushy.apns中的接口
-
A push notification that can be sent through the Apple Push Notification service (APNs).
- getExpiration() - 接口 中的方法com.relayrides.pushy.apns.ApnsPushNotification
-
Returns the time at which Apple's push notification service should stop trying to deliver this push notification.
- getExpiration() - 类 中的方法com.relayrides.pushy.apns.util.SimpleApnsPushNotification
-
Returns the time at which this push notification is no longer valid and should no longer be delivered.
- getLocaladdress() - 类 中的方法com.relayrides.pushy.apns.ApnsClient
-
- getPayload() - 接口 中的方法com.relayrides.pushy.apns.ApnsPushNotification
-
Returns the JSON-encoded payload of this push notification.
- getPayload() - 类 中的方法com.relayrides.pushy.apns.util.SimpleApnsPushNotification
-
Returns the payload to include in this push notification.
- getPriority() - 接口 中的方法com.relayrides.pushy.apns.ApnsPushNotification
-
Returns the priority with which this push notification should be sent to the receiving device.
- getPriority() - 类 中的方法com.relayrides.pushy.apns.util.SimpleApnsPushNotification
-
Returns the priority with which this push notification should be delivered to the receiving device.
- getPushNotification() - 接口 中的方法com.relayrides.pushy.apns.PushNotificationResponse
-
Returns the original push notification sent to the APNs gateway.
- getReconnectionFuture() - 类 中的方法com.relayrides.pushy.apns.ApnsClient
-
Returns a Future
that will succeed when the client has re-established a connection to the APNs gateway.
- getRejectionReason() - 接口 中的方法com.relayrides.pushy.apns.PushNotificationResponse
-
Returns the reason for rejection reported by the APNs gateway.
- getRemoteaddress() - 类 中的方法com.relayrides.pushy.apns.ApnsClient
-
- getToken() - 接口 中的方法com.relayrides.pushy.apns.ApnsPushNotification
-
Returns the token of the device to which this push notification is to be sent.
- getToken() - 类 中的方法com.relayrides.pushy.apns.util.SimpleApnsPushNotification
-
Returns the token of the device to which this push notification should be delivered.
- getTokenInvalidationTimestamp() - 接口 中的方法com.relayrides.pushy.apns.PushNotificationResponse
-
If the sent push notification was rejected because the destination token is no longer valid, returns the most
recent time at which the APNs gateway confirmed that the token is no longer valid.
- getTopic() - 接口 中的方法com.relayrides.pushy.apns.ApnsPushNotification
-
Returns the topic to which this notification should be sent.
- getTopic() - 类 中的方法com.relayrides.pushy.apns.util.SimpleApnsPushNotification
-
Returns the topic to which this push notification should be sent.
- sanitizeTokenString(String) - 类 中的静态方法com.relayrides.pushy.apns.util.TokenUtil
-
Returns a "sanitized" version of the given token string suitable for sending to an APNs server.
- sendNotification(T) - 类 中的方法com.relayrides.pushy.apns.ApnsClient
-
Sends a push notification to the APNs gateway.
- setAlertBody(String) - 类 中的方法com.relayrides.pushy.apns.util.ApnsPayloadBuilder
-
Sets the literal text of the alert message to be shown for the push notification.
- setAlertTitle(String) - 类 中的方法com.relayrides.pushy.apns.util.ApnsPayloadBuilder
-
Sets a short description of the notification purpose.
- setBadgeNumber(Integer) - 类 中的方法com.relayrides.pushy.apns.util.ApnsPayloadBuilder
-
Sets the number to display as the badge of the icon of the application that receives the push notification.
- setCategoryName(String) - 类 中的方法com.relayrides.pushy.apns.util.ApnsPayloadBuilder
-
Sets the name of the action category name for interactive remote notifications.
- setConnectionTimeout(int) - 类 中的方法com.relayrides.pushy.apns.ApnsClient
-
Sets the maximum amount of time, in milliseconds, that a client will wait to establish a connection with the
APNs server before the connection attempt is considered a failure.
- setContentAvailable(boolean) - 类 中的方法com.relayrides.pushy.apns.util.ApnsPayloadBuilder
-
Sets whether the payload under construction should contain a flag that indicates that new content is available
to be downloaded in the background by the receiving app.
- setFlushThresholds(int, long) - 类 中的方法com.relayrides.pushy.apns.ApnsClient
-
Sets the thresholds at which this client will flush notifications enqueued for sending to the APNs server.
- setGracefulShutdownTimeout(long) - 类 中的方法com.relayrides.pushy.apns.ApnsClient
-
Sets the amount of time (in milliseconds) clients should wait for in-progress requests to complete before closing
a connection during a graceful shutdown.
- setLaunchImageFileName(String) - 类 中的方法com.relayrides.pushy.apns.util.ApnsPayloadBuilder
-
Sets the image to be shown when the receiving app launches in response to this push notification.
- setLocalizedActionButtonKey(String) - 类 中的方法com.relayrides.pushy.apns.util.ApnsPayloadBuilder
-
Sets the key of a string in the receiving app's localized string list to be used as the label of the
"action" button if the push notification is displayed as an alert.
- setLocalizedAlertMessage(String, String[]) - 类 中的方法com.relayrides.pushy.apns.util.ApnsPayloadBuilder
-
Sets the key of a message in the receiving app's localized string list to be shown for the push notification.
- setLocalizedAlertTitle(String, String[]) - 类 中的方法com.relayrides.pushy.apns.util.ApnsPayloadBuilder
-
Sets the key of the title string in the receiving app's localized string list to be shown for the push
notification.
- setMetricsListener(ApnsClientMetricsListener) - 类 中的方法com.relayrides.pushy.apns.ApnsClient
-
Sets the metrics listener for this client.
- setProxyHandlerFactory(ProxyHandlerFactory) - 类 中的方法com.relayrides.pushy.apns.ApnsClient
-
Sets the proxy handler factory to be used to construct proxy handlers when establishing a new connection to the
APNs gateway.
- setShowActionButton(boolean) - 类 中的方法com.relayrides.pushy.apns.util.ApnsPayloadBuilder
-
Sets whether an "action" button should be shown if the push notification is displayed as an alert.
- setSoundFileName(String) - 类 中的方法com.relayrides.pushy.apns.util.ApnsPayloadBuilder
-
Sets the name of the sound file to play when the push notification is received.
- setWriteTimeout(long) - 类 中的方法com.relayrides.pushy.apns.ApnsClient
-
Sets the write timeout for this client.
- SimpleApnsPushNotification - com.relayrides.pushy.apns.util中的类
-
- SimpleApnsPushNotification(String, String, String) - 类 的构造器com.relayrides.pushy.apns.util.SimpleApnsPushNotification
-
Constructs a new push notification with the given token, topic, and payload.
- SimpleApnsPushNotification(String, String, String, Date) - 类 的构造器com.relayrides.pushy.apns.util.SimpleApnsPushNotification
-
Constructs a new push notification with the given token, topic, payload, and expiration time.
- SimpleApnsPushNotification(String, String, String, Date, DeliveryPriority) - 类 的构造器com.relayrides.pushy.apns.util.SimpleApnsPushNotification
-
Constructs a new push notification with the given token, topic, payload, delivery expiration time, and delivery
priority.
- Socks4ProxyHandlerFactory - com.relayrides.pushy.apns.proxy中的类
-
- Socks4ProxyHandlerFactory(SocketAddress) - 类 的构造器com.relayrides.pushy.apns.proxy.Socks4ProxyHandlerFactory
-
Creates a new proxy handler factory that will create SOCKS4 proxy handlers that use the proxy at the given
address and that will not perform authentication.
- Socks4ProxyHandlerFactory(SocketAddress, String) - 类 的构造器com.relayrides.pushy.apns.proxy.Socks4ProxyHandlerFactory
-
Creates a new proxy handler factory that will create SOCKS4 proxy handlers that use the proxy at the given
address and that will authenticate with the given username and password.
- Socks5ProxyHandlerFactory - com.relayrides.pushy.apns.proxy中的类
-
- Socks5ProxyHandlerFactory(SocketAddress) - 类 的构造器com.relayrides.pushy.apns.proxy.Socks5ProxyHandlerFactory
-
Creates a new proxy handler factory that will create SOCKS5 proxy handlers that use the proxy at the given
address and that will not perform authentication.
- Socks5ProxyHandlerFactory(SocketAddress, String, String) - 类 的构造器com.relayrides.pushy.apns.proxy.Socks5ProxyHandlerFactory
-
Creates a new proxy handler factory that will create SOCKS5 proxy handlers that use the proxy at the given
address and that will authenticate with the given username and password.


- New project for constructors. Specialize in industrial real estate.
- Specialize in industrial real estate.
- Build from scratch, rebuild existing real estate.
- Maintenance service agreement.
- Installs and repairs everything e.g. mixer, WC chairs and bathroom furniture
- Installs heat pumps, mountains, air-water, air-air
- New and rebuilding installations
- Finished Bathroom
- Energy Solutions, Solar heating Systems


With recent restrictions creating the demand for more engaging video content, our office set out to to create our own home-office / mobile lightboard. Making lightboards at home isn't something new. In fact, people have been creating their own lightboards for awhile and there are some really great resources out there to get you started.
For the purposes of this project, I wanted to see if I could build our team a lightboard using one of those resources while adding additional documentation and comparing costs for materials. In this example, I use Steve Griffith's article, 'How to Make a Lightboard for less than $100'. The article was written in 2016 and is featured on Flip Learning's website. Can we still do this for less than $100 in 2021? Let's find out!
Before starting the project, I spent some time considering the overall size. I wanted something large enough to capture a person and information being shared, but small enough it would easily fit inside most home-offices and vehicles for transportation; I decided on a 4' wide x 3' high design.
All materials were purchased at Lowes, except the glass; that was purchased at a custom framing center.
Making sure to be center, use a router or bench saw to cut a 1/2" wide x 1/2" deep recessed channel down the inside edge of each of the 4 pine frame boards.
Mark and mitre cut the four corners to create the lightboard frame. You can also use this opportunity to drill a hole in one side of the frame so that the electical chord from the LED light strip can pass through; I kept mine towards the bottom.
Using your two short pines (for the base), trim off 5" from the end of each board. Attach those trimmed blocks to the remaining board to create a support for your lightboard frame to rest against.
Using the wood glue and wood screws, begin to assemble the frame. Also begin attaching the bracket shelves and frame to the base using the coach screws, washers, and nuts. Important Note: Leave one end of your frame unglued so you can remove it later and slide in the glass.
Once you're certain everything is fitting together well, remove the frame from the base and paint; I used flat-black spray paint.
Once everything is dry, it's time to insert your LED light strip. Carefully press your LED light strip into the recessed channel of your lightboard. If your LED light strip is too long, you will need to trim it to fit. Important Note: If you need to trim your LED light strip, be sure to trim ONLY on the LED strip trim-line or you may break the LED strip; refer to your specific product's instructions.
If you've made it this far, it's time to order the glass. I took the frame to my local custom-frame shop, and they were able to measure and order a piece of 3M ultra clear glass to fit. It did take awhile to arrive, but once the glass came in, I brought it home and started the install.
Using caution (the edges / corners of the glass are sharp), remove the secton of the frame that you left unglued in Step 4. Once removed, slowly and CAREFULLY, slide your glass down the recessed channel and into place. The glass will rest directly on the LED light strip; that's okay.
Once you have your glass installed and the frame is reattached, connect your lightboard to the base, tighten nuts, and plug it in for a test run.
With our lightboard finished, it's time to add up our cost to see if we were able to come in under the $100 mark.
Unfortunately, I came in $57 over-budget. I attribute this mostly to the fact that I built a larger lightboard than the one used in the example article, and I also think the cost of some of these items has increased since the article was originally written in 2016.
However, even over budget, this was still an extremely cost-effective solution for creating more engaging video content, and the total build time (not counting the time it took to order the glass), was only about a day.
With your lightboard complete, it's time to start creating awesome videos. There are several important factors to consider when filming (studio setup, lighting, audio, backdrops, programs to edit your videos, etc.).
If you have questions regarding any of these extra areas, Steve Griffith's article, 'How to Make a Lightboard for less than $100' does a great job providing some extra use-cases / examples. I also found some great tips in the comments section. Beyond that, our office operates a full-size One-Button-Studio / lightboard, we would be happy to provide additional consultation to any faculty looking to enhance their video content.


Here's what you need to know about today's four by-elections
by NewstalkVoting is underway in the by-elections across the country.
Turnout has been low this morning with just one polling station topping 10% by noon.
It's expected voting will be low and slow across the day.
Candidates are conscious of competing for attention with Black Friday and tonight the Late Late Toy Show.
Here's a quick guide to the constituencies:
Wexford
Independents 4 Change TD Mick Wallace was one of the most colourful characters in Irish politics and his departure for Europe leaves a void that the two main parties are hoping to fill.
Wexford is a real mix of urban and rural with a large commuter population in the north of the constituency around Gorey and Enniscorthy.
Fianna Fáil's Malcolm Byrne is the favourite to take the seat. But some in the party in Wexford have been critical of his campaign and worry the race is far closer than it should be.
Fine Gael's Verona Murphy has been by far the most high profile candidate in these elections after her comments about asylum seekers, homeless people and the Road Safety Authority.
She pulled out of a number of debates and media appearances after the controversies and opinion on how she'll do varies widely in the constituency.
She's likely to get a strong vote in New Ross and is still in contention to take the seat.
The darkhorse here is Labour's George Lawlor who has a strong base in Wexford town and has run a very effective campaign.
Eyes will also be on Sinn Féin's Johnny Mythen who almost took a Dáil seat in 2016 but lost his council seat earlier this year.
Cork North Central
Cork North Central seems the most clear cut of the by-elections with Fianna Fáil's Padraig O'Sullivan the firm favourite to replace his party colleague Billy Kelleher.
Fine Gael Senator Colm Burke will also still be around at the business end of things tomorrow with some in the party thinking on a good day he can still take the seat.
Both Labour and Sinn Féin have run good campaigns here and Thomas Gould and John Maher will be happy with good performances that set them up well for the general election.
Cork North Central is a mix of urban and rural that extends from the city centre up to much more agricultural parts of the county. It's a good sample constituency for the rest of the country with a mix of working and middle class areas.
Dublin Fingal
Dublin Fingal is the seat of Independents 4 Change TD Clare Daly.
It's the youngest constituency in the country by demographic, with a massive amount of new developments without the infrastructure to match in some areas.
It ranges from areas like Swords and Malahide to rapidly expanding towns like Skerries.
There's three candidates in serious contention here with many tipping it as a two horse race between Labour and the Greens.
Councillor Duncan Smith of Labour has been backed from 7/1 right into the favourites position, but will face a still challenge from Green councillor Joe O'Brien.
It's a test of the Green wave seen in May's local elections and whichever of the two can stay in the race long enough to benefit from transfers could take it.
Fianna Fáil Senator Lorraine Clifford Lee could also take the seat despite being dogged by tweets she sent eight years ago through the campaign.
Dublin Midwest
This is probably the hardest constituency to call but many consider it a two horse race.
Fine Gael councillor Emer Higgins is looking to replace the former Tánaiste Frances Fitzgerald.
Fitzgerald had a huge electoral machine and pulled in votes from all across the constituency, something Higgins may struggle with.
She needs a clear lead after the first count to take the seat and if she doesn't have it Higgins could be caught by a number of candidates.
The favourite to challenge is former Green Party TD and current Independent Paul Gogarty.
He's well liked and respected in the constituency and will pull in transfers from across the board if he can stay in the race long enough to keep ahead of other candidates.
The performances of Fianna Fáil's Shane Moynihan, Sinn Féin's Mark Ward, Labour's Joanna Tuffy and Social Democrat Anne Marie McNally will also be closely watched.
Wexford candidates:
- Cinnamon Blackmore (Solidarity/People Before Profit)
- Malcolm Byrne (Fianna Fáil)
- Jim Codd (Aontú)
- Karin Dubsky (Green Party)
- Charlie Keddy (Independent)
- George Lawlor (Labour Party)
- Verona Murphy (Fine Gael)
- Johnny Mythen (Sinn Féin)
- Melissa O’Neill (Irish Freedom Party)
Dublin Mid-West candidates:
- David Gardiner (Workers’ Party)
- Paul Gogarty (Independent)
- Emer Higgins (Fine Gael)
- Peter Kavanagh (Green Party)
- Charlie Keddy (Independent)
- Peter Madden (Independent)
- Anne-Marie McNally (Social Democrats)
- Shane Moynihan (Fianna Fáil)
- Ruth Nolan (Independents4Change)
- Kellie Sweeney (Solidarity/People Before Profit)
- Francis Timmons (Independent)
- Joanna Tuffy (Labour Party)
- Mark Ward (Sinn Féin)
Dublin Fingal candidates:
- Glenn Brady (Independent)
- Tracey Carey (Social Democrats)
- Lorraine Clifford-Lee (Fianna Fáil)
- Ann Graves (Sinn Féin)
- Charlie Keddy (Independent)
- Cormac McKay (Independent)
- Joe O’Brien (Green Party)
- Gemma O’Doherty (Independent)
- Dean Mulligan (Independents 4 Change)
- James Reilly (Fine Gael)
- Peadar O’Kelly (Independent)
- Duncan Smith (Labour Party)
Cork North-Central candidates:
- Colm Burke (Fine Gael)
- Martin Condon (Independent)
- James Coughlan (Workers’ Party)
- Thomas Gould (Sinn Féin)
- Sinéad Halpin (Social Democrats)
- Charlie Keddy (Independent)
- Thomas Kiely (Independent)
- John Maher (Labour Party)
- Oliver Moran (Green Party)
- Pádraig O’Sullivan (Fianna Fáil)
- Fiona Ryan (Solidarity/People-Before-Profit)
- Finian Toomey (Aontú)


We recommend starting with this language involved with back end development. C# This language was designed by Microsoft and is a common language used by larger businesses for software development.
We recommend learning languages involved in both front end and back end development. C# and JavaScript The C# language was designed by Microsoft and is a common language used by larger businesses. The JavaScript language was created in 1995 and is used to make a webpage interactive. It is the only scripting language that all web browsers support
We recommend learning this language involved in front end development. JavaScript This language was created in 1995 and is used to make a webpage interactive. It is the only scripting language that all web browsers support.


Hello! I am a current first year CS student at University of Waterloo. I am interested in machine learning research and web development, and my favourite programming languages are java, python, JavaScript and HTML/CSS, and am looking forward to learning more. Aside from CS, I love music (guitar, violin, saxophone and song production), travelling and go game.


Kevin Campbell: 'Writing on the wall for Marco Silva at Everton'
Kevin Campbell has said that he thinks the writing is on the wall for Everton manager Marco Silva after his side's 2-0 defeat to Norwich City on Saturday.
by Andrew SinclairIt was a sixth defeat in nine games for the Toffees that leaves them just four points above the drop zone in 15th.
Speaking to Sky Sports News, former Everton striker Campbell said that he was struggling to see how the Portuguese boss could turn things round after Saturday's performance.
Campbell said: "The writing's on the wall, you've got to be realistic and hold your hands up - if the project or plan ain't working then there's no harm in rejigging the plan.
"Do you keep letting it hurtle towards the wall or do you redirect it and start making things happen?
"That's what the club ultimately going to have to do and it's going to take some strong leadership at the top and an element of ruthlessness.
"It's very difficult to come back from this and I don't see just how he's going to do it."
Everton face a difficult run of games before the end of 2019, with next weekend's trip to Leicester City followed by consecutive games against Liverpool, Chelsea and Manchester United.
body check tags ::


Across: 8. Craig confused about origin of light bulb (6) 9. Out of crazy lot, Queen using language particularly well (8) 10. Social prohibition on cycling to border (4) 11,21dn. Clever alien killing time, along with a pop star (5 6) 12. Perhaps pine for family structure? (4) 13. Explorer, in final leg, amazingly got 180 degrees around (8) 15. This bloke sounds fair dinkum (6) 16,2dn. Sudden increase in wind greeting illness taking a star of Australian TV (d 2021) and a star of French literature (b 1821) (7 8) 18. see 6 down 20. Ahmed's strangely embarrassed (6) 22. Advantages if Ben set anagram (8) 24. Pretty loud gas! (4) 25,14dn. All aid convivial arrangement of 11 21's work (5' 2 4 4) 27. Unfortunately, most salad is tossed (4) 28. Hannibal's father with that smile: scary, with no beginning or end (8) 29,22dn. 16 2's main work on crazy morning: taking turn to be egg producer (6 6) Down: 1. Country bin Lovelace (6) 2. see 16 across 3. Mark's second vehicle (4) 4. "Shining" might be a trick (6) 5. Ponder holy liquid and solid (10) 6,18ac. Judge university period offensive with bit of "Aladdin" by initially unthinking politician in 1 (6 7) 7. Breaking a French deal initially, leaders of rogue state envisage American submarine (8) 14. see 25 across 17. Disturbance of lava, eh? (8) 19. Rips off clothing, harbouring strange fear (8) 21. see 11 across 22. see 29 across 23. Upset with bad art by Thurman (6) 26. Nasty mean thing to call someone (4)


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ActiveTcl User Guide
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Tcl_GetStdChannel, Tcl_SetStdChannel - procedures for retrieving and replacing the standard channels
#include <tcl.h>
Tcl_Channel
Tcl_GetStdChannel(type)
Tcl_SetStdChannel(channel, type)
Tcl defines three special channels that are used by various I/O related commands if no other channels are specified. The standard input channel has a channel name of stdin and is used by read and gets. The standard output channel is named stdout and is used by puts. The standard error channel is named stderr and is used for reporting errors. In addition, the standard channels are inherited by any child processes created using exec or open in the absence of any other redirections.
The standard channels are actually aliases for other normal channels. The current channel associated with a standard channel can be retrieved by calling Tcl_GetStdChannel with one of TCL_STDIN, TCL_STDOUT, or TCL_STDERR as the type. The return value will be a valid channel, or NULL.
A new channel can be set for the standard channel specified by type by calling Tcl_SetStdChannel with a new channel or NULL in the channel argument. If the specified channel is closed by a later call to Tcl_Close, then the corresponding standard channel will automatically be set to NULL.
If Tcl_GetStdChannel is called before Tcl_SetStdChannel, Tcl will construct a new channel to wrap the appropriate platform-specific standard file handle. If Tcl_SetStdChannel is called before Tcl_GetStdChannel, then the default channel will not be created.
If one of the standard channels is set to NULL, either by calling Tcl_SetStdChannel with a NULL channel argument, or by calling Tcl_Close on the channel, then the next call to Tcl_CreateChannel will automatically set the standard channel with the newly created channel. If more than one standard channel is NULL, then the standard channels will be assigned starting with standard input, followed by standard output, with standard error being last.
See Tcl_StandardChannels for a general treatise about standard channels and the behaviour of the Tcl library with regard to them.
Tcl_Close, Tcl_CreateChannel, Tcl_Main, tclsh
standard channel, standard input, standard output, standard error
Copyright © 1996 by Sun Microsystems, Inc. Copyright © 1995-1997 Roger E. Critchlow Jr.


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This small town lies 100nm west of Dili, on the north coast of Timor. It is in the small enclave of Timor Leste, which is separated from the main part of the country. Its main link with the rest of the country is the weekly ferry from Dili.
Currently the area is undergoing significant upgrades to its infastructure. A very welcoming community and an interesting place to visit.
Position 09° 11'53"S, 124° 22'10"E (anchorage)
There does not appear to be any problem visiting here, even if you have already cleared out of Timor Leste at Dili.
Last updated August 2016.
There are few facilities for cruisers, but the holding in the sand at the anchorage off the town is excellent.
Last updated August 2016.


Resume
Education
Yale University, School of Forestry & Environmental Studies, New Haven, CT, 5/18
Masters of Environmental Management
University of Washington, Seattle, WA, 09/14 – 06/15
Certificate in Statistical Analysis with R Programming
Western Washington University , Bellingham, WA, 09/07 – 06/11
Bachelors of Science, Environmental Science with Chemistry minor
Experience
Metabolic – Green Chemistry Intern, Amsterdam, Netherlands, 05/17 – 08/17
- Designed theoretical framework and coded statistical scoring for software that predicts environmental impact and toxicity of chemical mixtures; project evolved into its own company
- Developed process flow diagram that evaluated lifecycle impacts of diverting steel gas exhaust for chemical production in report funded by a steel company, chemical manufacturer, and power generator
Data-Driven Yale – Student Researcher for Dr. Hsu, New Haven, CT, 07/16 – Present
- Led winning team in international UN Competition researching air pollution’s effect on credit card spending
Programmed methods to compare pollution and equity in an index comparing 20 global cities
Landau Associates, Inc. – Senior Staff Environmental Scientist, Seattle, WA, 04/12 – 01/16
- Supervised teams of up to 8 coworkers and subcontractors investigating subsurface contamination investigations
- Coordinatedand managed client relationships onsite in restricted industrial settings
- Trained new employees in sampling of air, groundwater, sediment, and soil using standardized methods with strict chain of custody protocols under demanding environmental conditions
Woods Hole Research Center – Student Researcher, Cherskiy, Siberia, 05/11 – 06/11
- Awarded fellowship studying climate change and permafrost thaw in the Siberian tundra
The Planet Magazine – Science Editor, Bellingham, WA, 09/10 – 06/11
- Edited over 60 stories for scientific accuracy and general audience readability in award-winning publication
WWU Chemistry Department – Student Researcher for Dr. O’Neil, Bellingham, WA, 03/09 – 06/10
- Synthesized molecules with hazardous and explosive materials
Leadership
WWU Huxley College Dean’s Advisory Board – Advisor, Seattle, WA, 06/13 – Present
- Selected for lifelong appointment to advisory board to contribute to Huxley’s College’s strategic vision
Air & Waste Management Association, Pacific Northwest International Section (A&WMA PNWIS) – Board Committee Member, Seattle, WA, 10/11 – 01/16
- Chaired fossil fuel exports in the Pacific Northwest meeting of over 100 professionals on the regulatory demands, environmental impacts, safety concerns, and business considerations
- Organized four “Environmental Challenge” competitions for up to 60 students in each challenge
Students for Renewable Energy – Vice President, Bellingham, WA , 09/07 – 06/11
- Led effort to establish a "Sustainable Action Fund" that annually awards $300K in student grants
Awards
United Nations – Data for Climate Action Thematic Award Winner, COP 23, Bonn, Germany, 11/17
A&WMA PNWIS – Young Professional of the Year, Spokane, WA, 10/14
WWU Sustainable Action Fund – $167K grant for an on–campus solar panel array, Bellingham, WA, 05/11
A&WMA – First Place in the Environmental Challenge International, Calgary, AB, 06/10


Python has been an object-oriented language from day one. Because of this, creating and using classes and objects are downright easy.
This chapter helps you become an expert in using Python's object-oriented programming support.
What is an object?
An object is an instance of a class. Now, that sentence is really short and very confusing. You will note that understanding what
a class, and an instance are is essential to understanding the definition given.
Getting this topic is very essential because creating your own classes is very important to maintaining your code, making your
application easy to read and understand.
Understanding this concept in programming will help you organise and be able to reuse your own code over and over again. Reusing your code will in turn save you a lot of time while coding. One more thing, it will help you write concise and shorter codes.
Creating Classes.
You follow a particular syntax to create classes in every language, but the general idea is to
create a blueprint or an outline of a pariticular module or class, define (def) it's various parts
(functions or methods) and what in particular each of these functions or methods do.
Declaring Objects.
After creating your class, you will require an object, which can "wear" or "take up" the form, attributes and methods of the class, this is the way to make your blueprint useful.
You might find the idea a bit daunting at first, you may be asking, "how do I put all of these together?"
Let's look at classes this way; you are human (an object of the human class) and you have parts (functions or methods) and these parts perform specific actions, and some, even multiple actions.
Let's take the hand for an example and let's assume for the purpose of getting this idea clearly, that you only use the hand to throw a ball. This implies that anytime you want to use the hand, you will need a ball. Because..? Of course, because as we agreed earlier, the hand is for throwing a ball.
Arguments/Parameters.
We agreed that we needed a ball to use the hand. Do not get so lost in the analogy, the hand is a part of the human class, so the hand represents a function. Now, the name given to the ball is an argument or a parameter. Our function needs a ball (a parameter) in order to throw. So, any time you call this function, you need to supply it with a ball.
You will do this in Python like this:
# Create an object of the human class and name it
Kofi = Human()
# Now call the function and supply it with a ball
Kofi.hand('ball')
Default arguments.
Sometimes, during the creation of your class, you could provide a default argument to your function, so that whenever a user of your class calls that function without providing it with an argument, the function will go and pick up that default argument you provided to work with. Make this clear in your documentation so that the default behavior of your function will not be a surprise.
Try this.
# importing the sys class
import sys
print("Hello")
sys.exit(0)
Now try this:
import sys
print("hello")
sys.exit()
So the first time, you supplied an argument and it worked fine, the next, you did not, it still did work fine. That is because, the one who created this function called "exit" from the class sys, supplied it with a default argument which gets supplied to the function in case you did not provide any argument like in the second case.
Always argue?
However, you will agree with me that not every function (part) should require an argument to work. And yes, it is not every function that we create that should require an argument. So you can create a function like that, when it gets called, it just does something without requiring the user to supply anything. Can you think of any situation like that?
Let's try this: If I said to you: "polish", you should definitely ask me for an argument, that is "what should I polish?", but if I said "jump", you sure can do that without any questions.
Let's put this in code:
# Let's define our function called polish
# Which always needs an argument
def polish(item):
print("polished ",item)
So, calling this function without providing an argument (what to polish) should raise an error.
Now, let's create one that does not require anything.
# Creating a function that does not require argument.
def jump():
print("Jumped")
The above requires no argument at all, so providing one will raise an error.
Take Note
A typical function should return a value, we use the keyword return to terminate a function.
So, if it is a calculation, then the return will return the final answer of the calculation.
print was used just to make things clearer.
Like this:
def area_of_triangle(base,height):
answer = 0.5*base*height
return answer
This is because, we typically do not print the value returned from a function but we use it for somthing else, we will like to leave that to whoever uses the function, whether the person would like to just print the "answer" to the console, pass it to another function, display it on a webpage or even pass it on to an artificial intelligence system, anything.
Putting it all together
Now, we can put all of these methods in one class, so when we create an object of that class, the object can perform all of these functions. So, we could define thousands of functions in one class and then create objects which will inherit these functions. You might already be guessing some powerful things you could use this ability for. It even gets much more exciting to know that there is the ability to inherit from other classes.
So, a class can serve as a parent class to other classes who then become the child classes. the child classes "inherit" the abilities of their parent class. We will talk about inheritance later, for now, lets create our own classes, a human class.
# Use the keyword class to begin and give it a name
class Human:
# We then initialise the class using __init__ method
# This gets called whenever a user object is created
def __init__(self,Name="Kojo"):
self.name = Name
def get_name(self):
return self.name
def set_name(self,Name):
self.name = Name
return self.name
def polish(self,item):
value_added = "polished"
return item,value_added
def jump(self):
return self.name, "jumped"
# Let's create an object of our class
# Remember our __init__ requires two arguments:
# Which are self (the object we created, so it's already supplied
# And a Name
Kofi = Human("Kofi")
# Let's get the name of our object Kofi
print(Kofi.get_name())
>>>Kofi
From our
__init__
method, we have provided a default Name for any object created, so if you created an object of our Human class without passing any Name, the get_name method will still return that default argument, whcih in this case is Kojo. But if you do provide a Name like in the above, then that Name will override the default Name(Kojo).
Let's set a new name for our object Kofi
print(Kofi.set_name("Adwoa))
>>>Adwoa
The self argument gets supplied to our method anytime we call the object so there's no need to supply it ourselves.
The get method is used to get attributes of our object, in this case we wrote one that gets the Name of the object, there are in_built get methods, also the set methods are used to modify those attributes, we also wrote an example ourselves, which sets a new Name for our object.
We then wrote two other methods, one is polish which takes an argument, particularly, the item to polish and returns a "polished" item.
The other method is jump, which just makes the object jumps.
So there, we have created our own class, provided our own getters and setters, and other methods.
We also learnt how to create an object of our class and how to put that object in use.
Can you think of other methods you could add?
How about some other attributes apart from the Name?, like skin color, hair color...
FootNote: Some PEP8 rules were broken on purpose, this is to make codes clearer in our opinion and to make differentiating easier. In the case of the variable Naming, where we used "Name" instead of "name" is an
example.
Further Readings
A class is an outline or a blueprint for creating an object. It is how an object will look like and how the various parts of that object
will function. Imagine an outline for a car, not the car itself but the outline, the various parts that will move to move
the whole car. All of these parts must be pre-defined and theoretically tested before creating the real object which is the physical car.
So, the physical car is a manifestation of the "plan" (outline).
Classes help hide data that should not be accessible to the user from the user (data abstraction).
Using the car example, you realise that while using a car, let's focus on driving and loading your stuff inside
the car as it's only usage (well, is there another usage?), you are allowed by the company that made
the car directly be able to control some parts of the car and even have a handbook on how to effectively control these parts.
However, some parts of the car are a bit restricted because you will mess things up if you were an allowed easy access.
This is exactly the concept that classes help you achieve and also allow you to group functions of the same entity together.
If you are wondering what these functions could be just think of the car example again: the functions will include
accelerate, so whenever the user calls accelerate, the car moves forward, reverse, break, steer right, steer left among others.
Basically, this is the idea, when you create a class of a car, then you have created a car with all its functions
but the car remains invisible and unusable until an object which is a physical manifestation of that car class is created.
The object assumes all the definitions of that class, and performs all the functions defined in the class suite.
When I say human, you definitely have an idea what a human looks like and the things that a human can do - that is the class.
Now, you will agree that every human have their unique features and abilities even though they all belong to the same blueprint (The Human Class).
In progrmming, this concept of every unique human being (object of the human class) having their own unique features is implemented by creating only one class
but having as many objects of that class as possible and each object having their own unique features (class variables).
Inheriting features from an "older" class is allowed, just like you inherited some features from your Mum or Dad.
Did you get the point?
In beginning, I said an object is an instance of a class. do you get the point now?
An object is an entity of a class, an object is the manifestation of a class.
When I say this is a dog, you definitely have a blueprint or outline of a dog in your mind
to agree or disagree with, so goes for any object, the object must have the features of it's class.
 In that sentence,
"a dog" is an object or an instance of the "dogs" class and "human" is an object
of the "humans" class.
Now let's move on to some terminologies and their definitions before creating our own classes and objects.
Overview of OOP Terminology
- Class: A user-defined prototype for an object that defines a set of attributes that characterize any object of the class.
The attributes are data members (class variables and instance variables) and methods, accessed via dot notation.
- Class variable: A variable that is shared by all instances of a class. Class variables are defined within a class but outside any of the class's methods.
Class variables aren't used as frequently as instance variables are.
- Data member: A class variable or instance variable that holds data associated with a class and its objects.
- Function overloading: The assignment of more than one behavior to a particular function. The operation performed varies by the types of objects (arguments) involved.
- Instance variable: A variable that is defined inside a method and belongs only to the current instance of a class.
- Inheritance : The transfer of the characteristics of a class to other classes that are derived from it.
- Instance: An individual object of a certain class. An object obj that belongs to a class Circle, for example, is an instance of the class Circle.
- Instantiation: The creation of an instance of a class.
- Method: A special kind of function that is defined in a class definition.
- Object: A unique instance of a data structure that's defined by its class. An object comprises both data members (class variables and instance variables) and methods.
- Operator overloading: The assignment of more than one function to a particular operator.
Creating Classes
The class statement creates a new class definition. The name of the class immediately follows the keyword class followed by a colon as follows:
class ClassName:
'Optional class documentation string'
class_suite
The class has a documentation string, which can be accessed via ClassName.__doc__.
The class_suite consists of all the component statements defining class members, data attributes and functions.
Example:
Following is the example of a simple Python class:
class Employee:
#This is the docstring
'Common base class for all employees'
# class variable
empCount = 0
# initialization method
def __init__(self, name, salary):
self.name = name
self.salary = salary
Employee.empCount += 1
#Other class methods
def displayCount(self):
print ("Total Employee %d" % Employee.empCount)
def displayEmployee(self):
print ("Name : ", self.name, ", Salary: ", self.salary)
The variable empCount is a class variable whose value would be shared among all instances of a this class. This can be accessed as
Employee.empCount
from inside the class or outside the class.
The first method
__init__()
is a special method, which is called class constructor or initialization method that Python calls when you create a new instance of this class.
You declare other class methods like normal functions with the exception that the first argument to each method is self.
Python adds the self argument to the list for you; you don't need to include it when you call the methods.
Creating instance objects
To create instances of a class, you call the class using class name and pass in whatever arguments its __init__ method accepts.
#This would create first object of Employee class called Effie
Effie = Employee("Effie", 6000)
#This would create second object of Employee class called Ellie
Ellie = Employee("Ellie", 4000)
So, those two objects (emp1 and emp2) belong to the same class called Employee and have their unique features which differentiates one from the other.
We created only one class but we could create two objects from that same class without wirting a class for the second object all over
again. If there were a thousand Employees, we could just create a thousand objects from the same class with thier own Names and Salaries.
Accessing attributes
You access the object's attributes using the dot operator with object. Class variable would be accessed using class name as follows:
Effie.displayEmployee()
Ellie.displayEmployee()
print ("Total Employee %d" % Employee.empCount)
Now, putting all the concepts together:
class Employee:
'Common base class for all employees'
empCount = 0
def __init__(self, name, salary):
self.name = name
self.salary = salary
Employee.empCount += 1
def displayCount(self):
print ("Total Employee %d" % Employee.empCount)
def displayEmployee(self):
print ("Name : ", self.name, ", Salary: ", self.salary)
#This would create first object of Employee class called emp1
emp1 = Employee("Effie", 2000)
#This would create second object of Employee class called emp2
emp2 = Employee("Theo", 5000)
emp1.displayEmployee()
emp2.displayEmployee()
print ("Total Employee %d" % Employee.empCount)
When the above code is executed, it produces the following result:
Name : Effie ,Salary: 3000
Name : Theo ,Salary: 5000
Total Employee 2
You can add, remove or modify attributes of classes and objects at any time:
emp1.age = 7 # Add an 'age' attribute.
emp1.age = 8 # Modify 'age' attribute.
del emp1.age # Delete 'age' attribute.
Instead of using the normal statements to access attributes,you can use following functions:
The getattr(obj, name[, default]) : to access the attribute of object.
The hasattr(obj,name) : to check if an attribute exists or not.
The setattr(obj,name,value) : to set an attribute.
If attribute does not exist, then it would be created.
The delattr(obj, name) : to delete an attribute.
hasattr(emp1, 'age') # Returns true if 'age' attribute exists
getattr(emp1, 'age') # Returns value of 'age' attribute
setattr(emp1, 'age', 8) # Set attribute 'age' at 8
delattr(empl, 'age') # Delete attribute 'age'
Built-In Class Attributes
Every Python class keeps following built-in attributes and they can be accessed using dot operator like any other attribute:
__dict__ : Dictionary containing the class's namespace.
__doc__ : Class documentation string or None if undefined.
__name__: Class name.
__module__: Module name in which the class is defined. This attribute is "__main__" in interactive mode.
__bases__ : A possibly empty tuple containing the base classes, in the order of their occurrence in the base class list.
For the above class let's try to access all these attributes:
class Employee:
'Common base class for all employees'
empCount = 0
def __init__(self, name, salary):
self.name = name
self.salary = salary
Employee.empCount += 1
def displayCount(self):
print "Total Employee %d" % Employee.empCount
def displayEmployee(self):
print "Name : ", self.name, ", Salary: ", self.salary
print ("Employee.__doc__:", Employee.__doc__)
print ("Employee.__name__:", Employee.__name__)
print ("Employee.__module__:", Employee.__module__)
print ("Employee.__bases__:", Employee.__bases__)
print ("Employee.__dict__:", Employee.__dict__)
When the above code is executed, it produces the following result:
Employee.__doc__: Common base class for all employees
Employee.__name__: Employee
Employee.__module__: __main__
Employee.__bases__: ()
Employee.__dict__: {'__module__': '__main__', 'displayCount':
, 'empCount': 2,
'displayEmployee': ,
'__doc__': 'Common base class for all employees',
'__init__': }
Destroying Objects (Garbage Collection)
Python deletes unneeded objects (built-in types or class instances) automatically to free memory space.
The process by which Python periodically reclaims blocks of memory that no longer are in use is termed garbage collection.
Python's garbage collector runs during program execution and is triggered when an object's reference count reaches zero. An object's reference count changes as the number of aliases that point to it changes.
An object's reference count increases when it's assigned a new name or placed in a container (list, tuple or dictionary).
The object's reference count decreases when it's deleted with del, its reference is reassigned, or its reference goes out of scope. When an object's reference count reaches zero, Python collects it automatically.
a = 40 # Create object <40>
b = a # Increase ref. count of <40>
c = [b] # Increase ref. count of <40>
del a # Decrease ref. count of <40>
b = 100 # Decrease ref. count of <40>
c[0] = -1 # Decrease ref. count of <40>
You normally won't notice when the garbage collector destroys an orphaned instance and reclaims its space.
But a class can implement the special method
__del__()
, called a destructor, that is invoked when the instance is about to be destroyed. This method might be used to clean up any nonmemory resources used by an instance.
Example:
This
__del__()
destructor prints the class name of an instance that is about to be destroyed:
class Point:
def __init( self, x=0, y=0):
self.x = x
self.y = y
def __del__(self):
class_name = self.__class__.__name__
print class_name, "destroyed"
pt1 = Point()
pt2 = pt1
pt3 = pt1
print id(pt1), id(pt2), id(pt3) # prints the ids of the obejcts
del pt1
del pt2
del pt3
When the above code is executed, it produces following result:
3083401324<PHONE_NUMBER><PHONE_NUMBER>
Point destroyed
Tip
Ideally, you should define your classes in separate file,
then you should import them in your main program file using import statement.
Kindly check
PywE Modules chapter for more details on importing modules and classes.
Class Inheritance
Instead of starting from scratch, you can create a class by deriving it from a preexisting class by listing the parent class in parentheses after the new class name.
The child class inherits the attributes of its parent class, and you can use those attributes
as if they were defined in the child class. A child class can also override data members and methods from the parent.
Just the way you would inherit the physical features of your parents and even their properties.
Syntax
Derived classes are declared much like their parent class; however, a list of base classes to inherit from are given after the class name:
class SubClassName (ParentClass1[, ParentClass2, ...]):
'Optional class documentation string'
class_suite
Example:
class Parent: # define parent class
parentAttr = 100
def __init__(self):
print ("Calling parent constructor")
def parentMethod(self):
print ('Calling parent method')
def setAttr(self, attr):
Parent.parentAttr = attr
def getAttr(self):
print "Parent attribute :", Parent.parentAttr
class Child(Parent): # define child class
def __init__(self):
print ("Calling child constructor")
def childMethod(self):
print ('Calling child method')
c = Child() # instance of child
c.childMethod() # child calls its method
c.parentMethod() # calls parent's method
c.setAttr(200) # again call parent's method
c.getAttr() # again call parent's method
When the above code is executed, it produces the following result:
Calling child constructor
Calling child method
Calling parent method
Parent attribute : 200
Similar way, you can derive a class from multiple parent classes as follows:
class A: # define your class A
.....
class B: # define your calss B
.....
class C(A, B): # subclass of A and B
.....
You can use
issubclass()
or
isinstance()
functions to check a relationships of two classes and instances.
The
issubclass(sub, sup)
boolean function returns true if the given subclass sub is indeed a subclass of the superclass sup.
The
isinstance(obj, Class)
boolean function returns true if obj is an instance of class Class or is an instance of a subclass of Class
Overriding Methods
You can always override your parent class methods. One reason for overriding parent's methods is because you may want special or different functionality in your subclass.
Example:
class Parent: # define parent class
def myMethod(self):
print ('Calling parent method')
class Child(Parent): # define child class
def myMethod(self):
print ('Calling child method')
c = Child() # instance of child
c.myMethod() # child calls overridden method
When the above code is executed, it produces the following result:
Calling child method
Base Overloading Methods
Following table lists some generic functionality that you can override in your own classes:
SN Method Description & Sample Call
1 __init__ ( self [,args...] )
Constructor (with any optional arguments)
Sample Call : obj = className(args)
2 __del__( self )
Destructor, deletes an object
Sample Call : del obj
3 __repr__( self )
Evaluatable string representation
Sample Call : repr(obj)
4 __str__( self )
Printable string representation
Sample Call : str(obj)
5 __cmp__ ( self, x )
Object comparison
Sample Call : cmp(obj, x)
Overloading Operators
Suppose you've created a Vector class to represent two-dimensional vectors, what happens when you use the plus operator to add them? Most likely Python will yell at you.
You could, however, define the __add__ method in your class to perform vector addition and then the plus operator would behave as per expectation:
Example:
class Vector:
def __init__(self, a, b):
self.a = a
self.b = b
def __str__(self):
return ('Vector (%d, %d)' % (self.a, self.b))
def __add__(self,other):
return (Vector(self.a + other.a, self.b + other.b))
v1 = Vector(2,10)
v2 = Vector(5,-2)
print (v1 + v2)
When the above code is executed, it produces the following result:
Vector(7,8)
Data Hiding
Remember we talked about hiding certain data from the user in order to prevent the user from messing up things?
An object's attributes may or may not be visible outside the class definition.
For these cases, you can name attributes with a double underscore prefix, and those attributes will not be directly visible to outsiders.
Example:
class JustCounter:
__secretCount = 0
def count(self):
self.__secretCount += 1
print (self.__secretCount)
counter = JustCounter()
counter.count()
counter.count()
print (counter.__secretCount)
When the above code is executed, it produces the following result:
1
2
Traceback (most recent call last):
File "test.py", line 12, in
print counter.__secretCount
AttributeError: JustCounter instance has no attribute '__secretCount'
Python protects those members by internally changing the name to include the class name. You can access such attributes as object._className__attrName.
If you would replace your last line as following, then it would work for you:
.........................
print (counter._JustCounter__secretCount)
When the above code is executed, it produces the following result:
1
2
2


R/TaskClassif.R
This task specializes Task and TaskSupervised for classification problems. The target column is assumed to be a factor. Predefined tasks are stored in mlr_tasks.
The task_type
is set to "classif"
.
R6::R6Class object inheriting from Task/TaskSupervised.
t = TaskClassif$new(id, backend, target, positive = NULL)
id
:: character(1)
Name of the task.
backend
:: DataBackend
Either a DataBackend, or any object which is convertible to a DataBackend with as_data_backend()
.
E.g., a data.frame()
will be converted to a DataBackendDataTable.
target
:: character(1)
Name of the target column.
positive
:: character(1)
Only for binary classification: Name of the positive class.
class_names
:: character()
Returns all class labels of the target column.
class_n
:: integer(1)
Returns the number of classes.
negative
:: character(1)
Stores the negative class for binary classification tasks, and NA
for multiclass tasks.
positive
:: character(1)
Stores the positive class for binary classification tasks, and NA
for multiclass tasks.
backend
:: DataBackend.
col_info
:: data.table::data.table()
Table with with 3 columns:
Column names of DataBackend are stored in columnid
.
Column type
holds the storage type of the variables, e.g. integer
, numeric
or character
.
Column levels
keeps a list of possible levels for factor and character variables.
col_roles
:: named list()
Each column (feature) can have an arbitrary number of roles in the learning task:
"target"
: Labels to predict.
"feature"
: Regular feature.
"order"
: Data returned by data()
is ordered by this column (or these columns).
"groups"
: During resampling, observations with the same value of the variable with role "groups"
are marked as "belonging together". They will be exclusively assigned to be either in the training set
or the test set for each resampling iteration. Only a single column may be marked as grouping column.
"weights"
: Observation weights. Only a single column may be marked as weights.
col_roles
keeps track of the roles with a named list of vectors of feature names.
To alter the roles, use t$set_col_role()
.
row_roles
:: named list()
Each row (observation) can have an arbitrary number of roles in the learning task:
"use"
: Use in train / predict / resampling.
"validation"
: Hold the observations back unless explicitly requested.
row_roles
keeps track of the roles with a named list of vectors of feature names.
To alter the role, use set_row_role()
.
feature_names
:: character()
Returns all column names with role == "feature"
.
feature_types
:: data.table::data.table()
Returns a table with columns id
and type
where id
are the column names of "active" features of the task
and type
is the storage type.
hash
:: character(1)
Hash (unique identifier) for this object.
id
:: character(1)
Stores the identifier of the Task.
measures
:: list()
of Measure
Stores the measures to use for this task.
ncol
:: integer(1)
Returns the total number of cols with role "target" or "feature".
nrow
:: integer(1)
Return the total number of rows with role "use".
row_ids
:: (integer()
| character()
)
Returns the row ids of the DataBackend for observations with with role "use".
target_names
:: character()
Returns all column names with role "target".
task_type
:: character(1)
Stores the type of the Task.
properties
:: character()
Set of task properties. Possible properties are are stored in
mlr_reflections$task_properties.
groups
:: data.table::data.table()
If the task has a designated column role "groups", table with two columns:
"row_id" (integer()
| character()
) and the grouping variable group
(vector()
).
Returns NULL
if there are is no grouping column.
weights
:: data.table::data.table()
If the task has a designated column role "weights", table with two columns:
"row_id" (integer()
| character()
) and the observation weights weight
(numeric()
).
Returns NULL
if there are is no weight column.
data(rows = NULL, cols = NULL, data_format = NULL)
(integer()
| character()
, character()
, character()
) -> any
Returns a slice of the data from the DataBackend in the data format specified by data_format
(depending on the DataBackend, but usually a data.table::data.table()
).
It is possible to provide multiple formats, the first format supported is selected.
Rows are subsetted to only contain observations with role "use".
Columns are filtered to only contain features with roles "target" and "feature".
If invalid rows
or cols
are specified, an exception is raised.
formula(rhs = NULL)
character()
-> formula
Constructs a stats::formula, e.g. [target] ~ [feature_1] + [feature_2] + ... + [feature_k]
, using
the features provided in argument rhs
(defaults to all active features).
levels(cols = NULL)
character()
-> named list()
Returns the distinct values of columns in cols
for columns with storage type "character", "factor" or "ordered".
Argument cols
defaults to all such columns with role "target" or "feature".
Note that this function ignores the row roles, it returns all levels available in the DataBackend.
To update the stored level information, e.g. after filtering a task, call $droplevels()
.
missings(cols = NULL)
character()
-> named integer()
Returns the number of missing values observations for each columns in cols
.
Argument cols
defaults to all columns with role "target" or "feature".
head(n = 6)
integer()
-> data.table::data.table()
Get the first n
observations with role "use".
set_col_role(cols, new_roles, exclusive = TRUE)
(character()
, character()
, logical(1)
) -> self
Adds the roles new_roles
to columns referred to by cols
.
If exclusive
is TRUE
, the referenced columns will be removed from all other roles.
set_row_role(rows, new_roles, exclusive = TRUE)
(character()
, character()
, logical(1)
) -> self
Adds the roles new_roles
to rows referred to by rows
.
If exclusive
is TRUE
, the referenced rows will be removed from all other roles.
filter(rows)
(integer()
| character()
) -> self
Subsets the task, reducing it to only keep the rows specified.
See the section on task mutators for more information.
select(cols)
character()
-> self
Subsets the task, reducing it to only keep the columns specified.
See the section on task mutators for more information.
cbind(data)
data.frame()
-> self
Extends the DataBackend with additional columns.
The row ids must be provided as column in data
(with column name matching the primary key name of the DataBackend).
If this column is missing, it is assumed that the rows are exactly in the order of t$row_ids
.
See the section on task mutators for more information.
rbind(data)
data.frame()
-> self
Extends the DataBackend with additional rows.
The new row ids must be provided as column in data
.
If this column is missing, new row ids are constructed automatically.
See the section on task mutators for more information.
replace_features(data)
data.frame()
-> self
Replaces some features of the task by constructing a completely new DataBackendDataTable.
This operation is similar to calling select()
and cbind()
, but explicitly copies the data.
See the section on task mutators for more information.
droplevels(cols = NULL)
character
-> self
Updates the cache of stored factor levels, removing all levels not present in the
set of active rows. cols
defaults to all columns with storage type "character", "factor", or "ordered".
Other Task: TaskRegr
,
TaskSupervised
, Task
,
mlr_generators
, mlr_tasks
data("Sonar", package = "mlbench") task = TaskClassif$new("sonar", backend = Sonar, target = "Class", positive = "M") task$task_type#> [1] "classif"task$formula()#> Class ~ V1 + V10 + V11 + V12 + V13 + V14 + V15 + V16 + V17 + #> V18 + V19 + V2 + V20 + V21 + V22 + V23 + V24 + V25 + V26 + #> V27 + V28 + V29 + V3 + V30 + V31 + V32 + V33 + V34 + V35 + #> V36 + V37 + V38 + V39 + V4 + V40 + V41 + V42 + V43 + V44 + #> V45 + V46 + V47 + V48 + V49 + V5 + V50 + V51 + V52 + V53 + #> V54 + V55 + V56 + V57 + V58 + V59 + V6 + V60 + V7 + V8 + #> V9 #> NULLtask$truth()#> [1] R R M M M M M M M M M M R M M M M M M M M M M R M M M M M M M M M M R M M #> [38] M M M M M M M M R M M M M M M M M M M R M M M M M M M M M M R M M M M M M #> [75] M M M M R M M M M M M M M M M R M M M M M M M M M M R M M M M M M M M M M #> [112] R R M M M M M M M M M R R R R R R R R R R R R R R R R R R R R R R R R R R #> [149] R R R R R R R R R R R R R R R R R R R R R R R R R R R R R R R R R R R R R #> [186] R R R R R R R R R R R R R R R R R R R R R M M #> Levels: M Rtask$class_names#> [1] "M" "R"task$positive#> [1] "M"task$negative#> [1] "R"# possible properties: mlr_reflections$task_properties$classif#> [1] "weights" "groups" "twoclass" "multiclass"


Secure Data Exchange Midlleware (SeDEM)
A Java Library to perform standard MQTT operations against an MQTT-compliant Broker
This library provide Java classes to perform publish and subscribe MQTT operations by means of the Event class it defines, which provide an Event creation method and implements an event callback listener. It makes easy all the operations against a MQTT Broker Server.
Initial Configuration
To permit a dynamic configuration of Logger and Application, the configuration files are external to the application jar. Then it is important using the following VM Arguments while running the main application (either in a .bat / .sh run file or as VM Arguments specified in the IDE).
-Drabbitmq_config_file=C:\resources\conf.properties -Dlog4j.configuration=file:C:\resources\log4j.properties
NOTE: if the library will be installed on a Linux O.S. it is important to use a Linux well formed path
Application configuration
The first step before using the library is the editing of the configuration parameters detailed below. The file named conf.properties is located in the external resource folder of the library (see the "Initial Configuration" introduction section).
Follow an example of configuration file:
MQTT_USERNAME=username
MQTT_PASSWORD=password
MQTT_CLIENT_ID=client_id_####
MQTT_QOS=1
MQTT_BROKER=broker.url.com
MQTT_PORT=8883
MQTT_PROTOCOL=ssl
MQTT_CLEARSESSION=true
MQTT_RETAINED=true
MQTT_TIME_TO_WAIT=100000
MQTT_TIMEOUT=30
MQTT_KEEP_ALIVE=125
CPABE_AES_ENCRYPTION=true
CPABE_POLICY=c:IT
CPABE_ANTICIPATED_KEY=true
CPABE_ANTICIPATED_KEY_IN_SECONDS=20
KEY_TYPE=EC
CRYPTOGRAPHIC_CURVE=P-256
ALG=ECDH-ES
ENC=A128GCM
PROXY_PROTOCOL=http
PROXY_IP=(abe-proxy-ip)
PROXY_PORT=(abe-proxy-port)
PROXY_ID=ABE-Proxy
STORAGE_TYPE=database
DB_IP=(key-storage-ip)
DB_PORT=(key-storage-port)
DB_AUTH_USER=(key-storage-username)
DB_AUTH_PWD=(key-storage-password)
DB_DATABASE=(key-storage-database)
DB_TABLE=(key-storage-table)
PAYLOAD_PATTERN=[{"value": "{"headers":{},"payload":""}"}]
PLACEHOLDER_PATTERN="{"headers":{},"payload":""}"
CONSUMER.PUBLIC_PARAM=C:/resources/Key/pub_10
CONSUMER.CPABE_PRIV_KEY=C:/Key/personal_key
Details about parameters:
- MQTT_USERNAME - username authorised to connect to MQTT Broker Server endpoint
- MQTT_PASSWORD - the password to authenticate against the MQTT Broker Server
- MQTT_CLIENT_ID - the unique client string identifier
- MQTT_QOS - Quality of Service level: 0 – at most once or 1 – at least once
- MQTT_BROKER - the endpoint address of the MQTT Broker Server
- MQTT_PORT - the port number where the MQTT Borker Service is listening on
- MQTT_PROTOCOL - the protocol used to perform the MQTT Broker connection
- MQTT_CLEARSESSION - the flag to specify if the persistence of the messages and subscriptions is required
- MQTT_RETAINED - the flag to specify the persistence of the message. All the messages flagged as retained will be stored by the broker
- MQTT_TIME_TO_WAIT - measured in milliseconds, it is the maximum time to wait for an action to complete
- MQTT_TIMEOUT - measured in seconds, it defines the maximum time interval the client will wait for the network connection to the MQTT server to be established
- MQTT_KEEP_ALIVE - measured in seconds, defines the ping interval to keep the connection opened. It is important to know the max keep alive of the server (e.g. 120s on Mosquitto)
- CPABE_AES_ENCRYPTION - flag to enable secure exchange of events
- CPABE_POLICY - the personal cpabe policy
- CPABE_ANTICIPATED_KEY - flag to enable the calculation of the anticipated key (the next key to be used)
- CPABE_ANTICIPATED_KEY_IN_SECONDS - the number of second before the key expiration date to start the anticipated key calculation
- KEY_TYPE, CRYPTOGRAPHIC_CURVE, ALG, ENC - details about the key type
- PROXY_PROTOCOL, PROXY_IP, PROXY_PORT, PROXY_ID - Abe Proxy endpoint details
- STORAGE_TYPE, DB_IP, DB_PORT, DB_AUTH_USER, DB_AUTH_PWD, DB_DATABASE, DB_TABLE - Key Storage endpoint details
- PAYLOAD_PATTERN and PLACEHOLDER_PATTERN - the message pattern details
- CONSUMER.PUBLIC_PARAM - the location of cpabe public key
- CONSUMER.CPABE_PRIV_KEY - the location of cpabe private key
Logging configuration
In the external resource folder of the library (see the "Initial Configuration" introduction section) is present a logging configuration file named
log4j.properties. It is possible edit this configuration file to change the file size and location and dimension, as well as logging level of the logger.
Following an example of the config logging file:
# Root logger option
log4j.rootLogger=INFO, stdout, file
# Redirect log messages to console
log4j.appender.stdout=org.apache.log4j.ConsoleAppender
log4j.appender.stdout.Target=System.out
log4j.appender.stdout.layout=org.apache.log4j.PatternLayout
log4j.appender.stdout.layout.ConversionPattern=%d{yyyy-MM-dd HH:mm:ss} %-5p %c{1}:%L - %m%n
# Redirect log messages to a log file, support file rolling.
log4j.appender.file=org.apache.log4j.RollingFileAppender
log4j.appender.file.File=C\:\\rabbitmq_client.log
#log4j.appender.file.File=/opt/logs/rabbitmq_client.log
log4j.appender.file.MaxFileSize=5MB
log4j.appender.file.MaxBackupIndex=10
log4j.appender.file.layout=org.apache.log4j.PatternLayout
log4j.appender.file.layout.ConversionPattern=%d{yyyy-MM-dd HH:mm:ss} %-5p %c{1}:%L - %m%n
NOTE: if the library is installed on a Linux O.S. it is important to change the log file path (see the commented line)
Library dependencies
The library has 2 main dependencies:
- log4j, a Java Logging Library
- Eclipse Paho library to interact with the MQTT Broker Server
The library will be provided as mavenized JAR including the dependencies, then the application that use the library must import also this jar.
An example of use
In the
com.fincons.mqtt.client.test package is present a simple example of Publish and Subscribe Scenario including a Simple MQTT Callback class that is invoked when a new MQTT message arrives.
Please refer to the classes included in the package above for more details.


| College of Engineering, | Email<EMAIL_ADDRESS>|
| Mathematics and Physical Sciences | Telephone: +44 (0) 1392 725358 |
| University of Exeter | Web: emps.exeter.ac.uk/mathematics/staff/ajf223 |
| North Park Road, | Twitter: angusferraro |
| Exeter, EX4 4QF, UK |
| I am a physical climate scientist with interests in the terrestrial hydrological cycle and atmospheric radiative transfer. I use climate model simulations in conjunction with remote sensing observations to enhance fundamental physical understanding of the climate system. I am also interested in the emerging technology of climate geoengineering and how this interacts with conventional climate policy. |
PhD, Atmosphere, Oceans and Climate, University of Reading, Reading, UK
Atmospheric responses to geoengineering in the stratosphere
Investigating the impacts of an enhanced stratospheric sulphate layer on stratospheric dynamics and communication of these effects to the troposphere. Supervisors: Dr. Andrew Charlton-Perez and Prof. Eleanor Highwood.
BSc, Meteorology (First Class Honours), University of Reading, Reading, UK
Dissertation: Factors influencing the climate sensitivity parameter in a zero-dimensional climate model. Supervisor: Prof. Keith Shine.
Research Fellow, University of Exeter, Exeter, UK
Process-Based Emergent Physical and Biogeochemical Feedbacks
Constraints on the lapse rate, water vapour and cloud climate feedbacks. Collaborators: Prof. Mat Collins and Dr. Hugo Lambert.
Research assistant, Met Office, Exeter, UK
Impacts of Arctic sea ice retreat on ocean-atmosphere coupling. Supervisor: Dr. Peili Wu.
Runner-up, College of Engineering, Mathematics and Physical Sciences Early-Career Researcher poster competition, 2015.
Overall Undergraduate Prize for academic excellence, University of Reading, 2010
Supervision of summer student. Direct and indirect drivers of precipitation change in a geoengineered world. June-July 2015.
Co-supervision of MMath student with Hugo Lambert (University of Exeter) and contributions from Manoj Joshi (University of East Anglia)
Geoengineering and the tropical overturning circulation
Demonstrator/tutor for undergraduates at Department of Meteorology, University of Reading
Introduction to Atmospheric Science
Fluid Dynamics of Atmosphere and Oceans
Geoengineering aerosols and how they might affect climate and circulation. IOP Environmental Physics Members' Day, London.
Physical mechanisms of tropical climate feedbacks revealed by temperature and moisture trends, (poster) CFMIP conference, Asilomar, USA.
Physical mechanisms of tropical climate feedbacks revealed by temperature and moisture trends, (poster) EGU General Assembly, Vienna, Austria.
Impact of aerosol & dimmed-sun geoengineering on stratospheric dynamics, 3rd GeoMIP workshop, Potsdam, Germany.
Atmospheric responses to stratospheric aerosol geoengineering, EGU General Assembly, Vienna, Austria.
Personal blog summarising recent advances in climate science; contributions to the WCD blog (Department of Meteorology, University of Reading), the GeoBlog (Oxford Geoengineering Programme, University of Oxford) and the GeoLog (European Geosciences Union).
Ferraro, A. J. and H. G. Griffiths, 2016: Quantifying the temperature-independent effect of stratospheric aerosol geoengineering on global-mean precipitation in a multi- model ensemble. Environmental Research Letters, 11, 034012, doi:10.1088/1748-9326/11/3/034012.
Ferraro, A. J., F. H. Lambert, M. Collins, and G. Miles, 2015: Physical mechanisms of tropical climate feedbacks revealed by temperature and moisture trends. Journal of Climate, 28, 8968-8987, doi:10.1175/JCLI-D-15-0253.1.
Ferraro, A. J., M. Collins, and F. H. Lambert, 2015: A hiatus in the stratosphere?. Nature Climate Change, 5, 497-498, doi:10.1038/nclimate2624.
Citations: 1
Ferraro, A. J., A. J. Charlton-Perez, and E. J. Highwood, 2015: Stratospheric dynamics and midlatitude jets under geoengineering with space mirrors and sulfate and titania aerosols. J. Geophys. Res. Atmos., 120, 414-429, doi:10.1002/2014jd022734.
Ferraro, A. J., A. J. Charlton-Perez, and E. J. Highwood, 2014: A Risk-Based Framework for Assessing the Effectiveness of Stratospheric Aerosol Geoengineering. PLoS ONE, 9, e88849, doi:10.1371/journal.pone.0088849.
Citations: 3
Part of the PLOS 'Responding to Climate Change' collection
Ferraro, A. J., E. J. Highwood, and A. J. Charlton-Perez, 2014: Weakened tropical circulation and reduced precipitation in response to geoengineering. Environ. Res. Lett., 9, 014001, doi:10.1088/1748-9326/9/1/014001.
Citations: 9
One of 25 highlights of 2014 in Environmental Research Letters
Extensive media coverage including BBC, Guardian, The Independent, phys.org, New Zealand Herald, Bangkok Post, Hindustan Times.
Ferraro, A. J., E. J. Highwood, and A. J. Charlton-Perez, 2011: Stratospheric heating by potential geoengineering aerosols. Geophysical Research Letters, 38, doi:10.1029/2011gl049761.
Citations: 13
Research Highlight in Nature Climate Change


pick masking - only the green objects are picked on mouseover
- from model, build random list of meshes to be included in picking
- ghost the excluded meshes, color the rest green
- pick and highlight only the included meshes on mouse-over, don't attempt to pick the rest
- model by https://sketchfab.com/tflexcad