com.amazonaws.services.simpleworkflow.flow.core

クラス Settable<V>

java.lang.Object

com.amazonaws.services.simpleworkflow.flow.core.Promise<V>

com.amazonaws.services.simpleworkflow.flow.core.Settable<V>

型パラメータ:

V - The type of value accepted and returned by this Settable.Use Void to represent Promise that indicates completion of operation that doesn't return a value.

public class Settable<V>
extends Promise<V>

It is an implementation of Promise, which exposes an additional set(Object) and chain(Promise) methods. Calling set(Object) puts it in ready state, with value retrievable through get() method. chain(Promise) links state of this Settable to another Promise. When another promise changes its state to ready the chained one is also becomes ready.

Use settable.set(null) to set Settable<Void> to the ready state.

Settable is frequently used to return data from code contained in anonymous classes. For example:

 
 Promise<Integer> foo() {
     final Settable<Integer> result = new Settable<Integer>();
     new TryCatch() {
                            
         protected void doTry() throws Throwable {
             Promise<Integer> activity1Result = activities.callActivity1();
             result.chain(activity1Result);
         }
                            
         protected void doCatch(Throwable e) throws Throwable {
             Promise<Void> handled = handleFailure(e);
             rethrow(e, handled);
         }
      };
      return result;
 }
 
 

コンストラクタの概要

コンストラクタ

コンストラクタと説明
Settable()
Settable(V value)

メソッドの概要

メソッド

修飾子とタイプ	メソッドと説明
protected void	addCallback(java.lang.Runnable callback) Compliant implementation should notify callbacks after promise is set to ready state.
void	chain(Promise<V> chainTo) Used to chain this Settable with the passed in Promise.
V	get()
java.lang.String	getDescription()
boolean	isReady()
protected void	removeCallback(java.lang.Runnable callback)
void	set(V value)
void	setDescription(java.lang.String description)
java.lang.String	toString()
void	unchain() Used to unchain this Settable from the Promise object passed in last invocation of chain.

クラスから継承されたメソッド com.amazonaws.services.simpleworkflow.flow.core.Promise

asPromise, Void

クラスから継承されたメソッド java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait

コンストラクタの詳細

Settable

public Settable(V value)

Settable

public Settable()

メソッドの詳細

get

public V get()

定義:

get クラス内 Promise<V>

戻り値:

The value passed in when set() is called

例外:

java.lang.IllegalStateException - If set() is never called for this instance of Settable

isReady

public boolean isReady()

定義:

isReady クラス内 Promise<V>

戻り値:

true if set() is called for this Settable

set

public void set(V value)

パラメータ:

value - Object to return when get() is called for this Settable. Use null to set Settable<Void> to the ready state.

例外:

java.lang.IllegalStateException - if the Promise is already in ready state

chain

public void chain(Promise<V> chainTo)

Used to chain this Settable with the passed in Promise. This allows the Settable to be ready whenever the passed in Promise is ready and the value for the chained Promise can be retrieved by calling get() method on this Settable.

パラメータ:

chainTo - Promise object to chain this Settable to. Chaining to null equates calling set(Object) with null argument.

例外:

java.lang.IllegalStateException - if Settable is already in ready state or it is already chained to some other Promise

関連項目:

unchain()

unchain

public void unchain()

Used to unchain this Settable from the Promise object passed in last invocation of chain. There is no requirement to unchain unless there is a need to chain the Settable to another Promise. Such need usually appears when implementing recursive functions or in TryCatchFinally.doCatch(Throwable) blocks. It is safe to call unchain if chain is never called for this Settable.

例外:

java.lang.IllegalStateException - If the Promise it is chained to is already in the ready state

addCallback

protected void addCallback(java.lang.Runnable callback)

クラスからコピーされた説明: Promise

Compliant implementation should notify callbacks after promise is set to ready state.

定義:

addCallback クラス内 Promise<V>

パラメータ:

callback - callback to notify

removeCallback

protected void removeCallback(java.lang.Runnable callback)

定義:

removeCallback クラス内 Promise<V>

getDescription

public java.lang.String getDescription()

オーバーライド:

getDescription クラス内 Promise<V>

戻り値:

human friendly description on what this promise represents. Emitted for example as part of AsyncScope.getAsynchronousThreadDumpAsString()

setDescription

public void setDescription(java.lang.String description)

パラメータ:

description - human readable description of what this Promise represents.

関連項目:

Promise.getDescription()

toString

public java.lang.String toString()

オーバーライド:

toString クラス内 java.lang.Object