Promise (Vert.x Stack - Docs 4.1.8 API)

All Superinterfaces:

Handler<AsyncResult<T>>

All Known Subinterfaces:

ApolloWSConnectionInitEvent, BaseBridgeEvent, BridgeEvent, BridgeEvent
```
public interface Promise<T>
extends Handler<AsyncResult<T>>
```
Represents the writable side of an action that may, or may not, have occurred yet.
The future() method returns the Future associated with a promise, the future can be used for getting notified of the promise completion and retrieve its value.
A promise extends Handler<AsyncResult<T>> so it can be used as a callback.

Author:

Julien Viet

Method Summary

All Methods Static Methods Instance Methods Abstract Methods Default Methods
Modifier and Type	Method and Description
`default void`	`complete()` Calls `complete(null)`
`default void`	`complete(T result)` Set the result.
`default void`	`fail(String message)` Calls `fail(Throwable)` with the `message`.
`default void`	`fail(Throwable cause)` Set the failure.
`Future<T>`	`future()`
`default void`	`handle(AsyncResult<T> asyncResult)` Succeed or fail this promise with the `AsyncResult` event.
`static <T> Promise<T>`	`promise()` Create a promise that hasn't completed yet
`default boolean`	`tryComplete()` Calls `tryComplete(null)`.
`boolean`	`tryComplete(T result)` Like `complete(Object)` but returns `false` when the promise is already completed instead of throwing an `IllegalStateException`, it returns `true` otherwise.
`default boolean`	`tryFail(String message)` Calls `fail(Throwable)` with the `message`.
`boolean`	`tryFail(Throwable cause)` Like `fail(Throwable)` but returns `false` when the promise is already completed instead of throwing an `IllegalStateException`, it returns `true` otherwise.

- Method Detail
  - promise
```
static <T> Promise<T> promise()
```
    Create a promise that hasn't completed yet
    
    Type Parameters:
    
    T - the result type
    
    Returns:
    
    the promise
  - handle
```
default void handle(AsyncResult<T> asyncResult)
```
    Succeed or fail this promise with the AsyncResult event.
    
    Specified by:
    
    handle in interface Handler<AsyncResult<T>>
    
    Parameters:
    
    asyncResult - the async result to handle
  - complete
```
default void complete(T result)
```
    Set the result. Any handler will be called, if there is one, and the promise will be marked as completed.
    Any handler set on the associated promise will be called.
    
    Parameters:
    
    result - the result
    
    Throws:
    
    IllegalStateException - when the promise is already completed
  - complete
```
default void complete()
```
    Calls complete(null)
    
    Throws:
    
    IllegalStateException - when the promise is already completed
  - fail
```
default void fail(Throwable cause)
```
    Set the failure. Any handler will be called, if there is one, and the future will be marked as completed.
    
    Parameters:
    
    cause - the failure cause
    
    Throws:
    
    IllegalStateException - when the promise is already completed
  - fail
```
default void fail(String message)
```
    Calls fail(Throwable) with the message.
    
    Parameters:
    
    message - the failure message
    
    Throws:
    
    IllegalStateException - when the promise is already completed
  - tryComplete
```
boolean tryComplete(T result)
```
    Like complete(Object) but returns false when the promise is already completed instead of throwing an IllegalStateException, it returns true otherwise.
    
    Parameters:
    
    result - the result
    
    Returns:
    
    false when the future is already completed
  - tryComplete
```
default boolean tryComplete()
```
    Calls tryComplete(null).
    
    Returns:
    
    false when the future is already completed
  - tryFail
```
boolean tryFail(Throwable cause)
```
    Like fail(Throwable) but returns false when the promise is already completed instead of throwing an IllegalStateException, it returns true otherwise.
    
    Parameters:
    
    cause - the failure cause
    
    Returns:
    
    false when the future is already completed
  - tryFail
```
default boolean tryFail(String message)
```
    Calls fail(Throwable) with the message.
    
    Parameters:
    
    message - the failure message
    
    Returns:
    
    false when the future is already completed
  - future
```
Future<T> future()
```
    Returns:
    
    the Future associated with this promise, it can be used to be aware of the promise completion

Interface Promise<T>

Method Summary

Method Detail

promise

handle

complete

complete

fail

fail

tryComplete

tryComplete

tryFail

tryFail

future