Package cn.dinodev.spring.commons.promise

Interface Promise<D>

Type Parameters:

D - 用于成功回调的数据类型

All Superinterfaces:

Supplier<D>

All Known Subinterfaces:

Deferred<D>

All Known Implementing Classes:

AbstractPromise, DeferredObject

public interface Promise<D>
extends Supplier<D>

Promise接口，用于观察对应Deferred对象上发生的操作

Promise对象应该从Deferred.promise()获取，或通过DeferredManager使用。

 
 Deferred<String> deferredObject = new DeferredObject<>();
 Promise<String> promise = deferredObject.promise();
 promise.done(result -> {
     // 处理成功结果
 });

 // 另一个线程使用同一个deferredObject
 deferredObject.resolve("OK");
 
 

Author:

Ray Tsang, Stephan Classen

Nested Class Summary

Nested Classes

Modifier and Type	Interface	Description
static enum	Promise.State	Promise的状态

Method Summary

Modifier and Type	Method	Description
Promise<D>	always(AlwaysCallback<? super D> callback)	This method will register AlwaysCallback so that when a Deferred object is either resolved (Deferred.resolve(Object)) or rejected ( invalid reference Deferred#reject(Object) ), AlwaysCallback will be triggered.
Promise<D>	done(Consumer<? super D> callback)	This method will register invalid reference DoneCallback so that when a Deferred object is resolved (Deferred.resolve(Object)), invalid reference DoneCallback will be triggered.
Promise<D>	fail(Consumer<Throwable> callback)	This method will register invalid reference FailCallback so that when a Deferred object is rejected ( invalid reference Deferred#reject(Object) ), invalid reference FailCallback will be triggered.
D	getOrElse(D defaultValue)	get the resolved value， return defaultValue for rejected
D	getOrElse(Supplier<D> defaultSupplier)	get the resolved value， return defaultSupplier‘s result for rejected
boolean	isPending()	Queries the state of this promise, returning true iff it is State.PENDING.
boolean	isRejected()	Queries the state of this promise, returning true iff it is State.REJECTED.
boolean	isResolved()	Queries the state of this promise, returning true iff it is State.RESOLVED.
Promise.State	state()	状态
Promise<D>	then(Consumer<? super D> doneCallback)	Equivalent to done(DoneCallback)
Promise<D>	then(Consumer<? super D> doneCallback, Consumer<Throwable> failCallback)	Equivalent to done(DoneCallback).fail(FailCallback)
void	waitSafely()	This method will wait as long as the State is Pending.
void	waitSafely(long timeout)	This method will wait when the State is Pending, and return when timeout has reached.

Methods inherited from interface java.util.function.Supplier

get

Method Details

state

Promise.State state()

状态

Returns:

the state of this promise.

isPending

boolean isPending()

Queries the state of this promise, returning true iff it is State.PENDING.

Returns:

true if the current state of this promise is State.PENDING, false otherwise.

See Also:

• Promise.State.PENDING

isResolved

boolean isResolved()

Queries the state of this promise, returning true iff it is State.RESOLVED.

Returns:

true if the current state of this promise is State.RESOLVED, false otherwise.

See Also:

• Promise.State.RESOLVED

isRejected

boolean isRejected()

Queries the state of this promise, returning true iff it is State.REJECTED.

Returns:

true if the current state of this promise is State.REJECTED, false otherwise.

See Also:

• Promise.State.REJECTED

getOrElse

D getOrElse(D defaultValue)

get the resolved value， return defaultValue for rejected

Parameters:

defaultValue - 默认值

Returns:

如果Promise已解决则返回解决的值，否则返回默认值

getOrElse

D getOrElse(Supplier<D> defaultSupplier)

get the resolved value， return defaultSupplier‘s result for rejected

Parameters:

defaultSupplier - 默认值提供者

Returns:

如果Promise已解决则返回解决的值，否则返回默认值

then

Promise<D> then(Consumer<? super D> doneCallback)

Equivalent to done(DoneCallback)

Parameters:

doneCallback - see done(DoneCallback)

Returns:

this for chaining more calls

then

Promise<D> then(Consumer<? super D> doneCallback,
 Consumer<Throwable> failCallback)

Equivalent to done(DoneCallback).fail(FailCallback)

Parameters:

doneCallback - see done(DoneCallback)

failCallback - see fail(FailCallback)

Returns:

this for chaining more calls

done

Promise<D> done(Consumer<? super D> callback)

This method will register

invalid reference

DoneCallback

so that when a Deferred object is resolved (Deferred.resolve(Object)),

invalid reference

DoneCallback

will be triggered. If the Deferred object is already resolved then the

invalid reference

DoneCallback

is triggered immediately. You can register multiple

invalid reference

DoneCallback

by calling the method multiple times. The order of callback trigger is based on the order they have been registered.

 
 promise.progress(new DoneCallback(){
   public void onDone(Object done) {
     ...
   }
 });
 
 

Parameters:

callback - the callback to be triggered

Returns:

this for chaining more calls

See Also:

• Deferred.resolve(Object)

fail

Promise<D> fail(Consumer<Throwable> callback)

This method will register

invalid reference

FailCallback

so that when a Deferred object is rejected (

invalid reference

Deferred#reject(Object)

),

invalid reference

FailCallback

will be triggered. If the Deferred object is already rejected then the

invalid reference

FailCallback

is triggered immediately. You can register multiple

invalid reference

FailCallback

by calling the method multiple times. The order of callback trigger is based on the order they have been registered.

 
 promise.fail(new FailCallback(){
   public void onFail(Object rejection) {
     ...
   }
 });
 
 

Parameters:

callback - the callback to be triggered

Returns:

this for chaining more calls

See Also:

• invalid reference

  Deferred#reject(Object)

always

Promise<D> always(AlwaysCallback<? super D> callback)

This method will register AlwaysCallback so that when a Deferred object is either resolved (Deferred.resolve(Object)) or rejected (

invalid reference

Deferred#reject(Object)

), AlwaysCallback will be triggered. If the Deferred object is already resolved or rejected then the AlwaysCallback is triggered immediately. You can register multiple AlwaysCallback by calling the method multiple times. The order of callback trigger is based on the order they have been registered. AlwaysCallbacks are triggered after any

invalid reference

DoneCallback

or

invalid reference

FailCallback

respectively.

 
 promise.always(new AlwaysCallback(){
   public void onAlways(State state, Object result, Object rejection) {
     if (state == State.RESOLVED) {
       // do something with result
     } else {
       // do something with rejection
     }
   }
 });
 
 

Parameters:

callback - the callback to be triggered

Returns:

this for chaining more calls

See Also:

• Deferred.resolve(Object)
• invalid reference

  Deferred#reject(Object)

waitSafely

void waitSafely()
         throws InterruptedException

This method will wait as long as the State is Pending. This method will return fast when State is not Pending.

Throws:

InterruptedException - if thread is interrupted while waiting

waitSafely

void waitSafely(long timeout)
         throws InterruptedException

This method will wait when the State is Pending, and return when timeout has reached. This method will return fast when State is not Pending.

Parameters:

timeout - the maximum time to wait in milliseconds

Throws:

InterruptedException - if thread is interrupted while waiting