Package org.osgi.util.promise

Class FailedPromiseImpl<T>

  • Type Parameters:
    T - The result type associated with the Promise.
    All Implemented Interfaces:
    Promise<T>
    final class FailedPromiseImpl<T>
extends PromiseImpl<T>
    Failed Promise implementation.

    This class is not used directly by clients. Clients should use PromiseFactory.failed(Throwable) to create a failed Promise.

    Since:
    1.1

    • Field Detail

      • fail

        private final java.lang.Throwable fail
        The failure of this failed Promise.

    • Constructor Detail

      • FailedPromiseImpl

        FailedPromiseImpl​(java.lang.Throwable fail,
                  PromiseFactory factory)
        Initialize this failed Promise.
        Parameters:
        fail - The failure of this failed Promise. Must not be null.
        factory - The factory to use for callbacks and scheduled operations.

    • Method Detail

      • isDone

        public boolean isDone()
        Returns whether this Promise has been resolved.

        This Promise may be successfully resolved or resolved with a failure.

        Returns:
        true if this Promise was resolved either successfully or with a failure; false if this Promise is unresolved.

      • getValue

        public T getValue()
           throws java.lang.reflect.InvocationTargetException
        Returns the value of this Promise.

        If this Promise is not resolved, this method must block and wait for this Promise to be resolved before completing.

        If this Promise was successfully resolved, this method returns with the value of this Promise. If this Promise was resolved with a failure, this method must throw an InvocationTargetException with the failure exception as the cause.

        Returns:
        The value of this resolved Promise.
        Throws:
        java.lang.reflect.InvocationTargetException - If this Promise was resolved with a failure. The cause of the InvocationTargetException is the failure exception.

      • getFailure

        public java.lang.Throwable getFailure()
        Returns the failure of this Promise.

        If this Promise is not resolved, this method must block and wait for this Promise to be resolved before completing.

        If this Promise was resolved with a failure, this method returns with the failure of this Promise. If this Promise was successfully resolved, this method must return null.

        Returns:
        The failure of this resolved Promise or null if this Promise was successfully resolved.

      • toString

        public java.lang.String toString()
        Overrides:
        toString in class java.lang.Object

      • coerce

        private <V> FailedPromiseImpl<V> coerce()
        Coerce the value type of this FailedPromiseImpl.
        Returns:
        This FailedPromiseImpl.

      • onSuccess

        public Promise<T> onSuccess​(Consumer<? super T> success)
        Register a callback to be called with the result of this Promise when this Promise is resolved successfully. The callback will not be called if this Promise is resolved with a failure.

        This method may be called at any time including before and after this Promise has been resolved.

        Resolving this Promise happens-before any registered callback is called. That is, in a registered callback, Promise.isDone() must return true and Promise.getValue() and Promise.getFailure() must not block.

        A callback may be called on a different thread than the thread which registered the callback. So the callback must be thread safe but can rely upon that the registration of the callback happens-before the registered callback is called.

        Specified by:
        onSuccess in interface Promise<T>
        Overrides:
        onSuccess in class PromiseImpl<T>
        Parameters:
        success - The Consumer callback that receives the value of this Promise. Must not be null.
        Returns:
        This Promise.

      • then

        public <R> Promise<R> then​(Success<? super T,​? extends R> success,
                           Failure failure)
        Chain a new Promise to this Promise with Success and Failure callbacks.

        The specified Success callback is called when this Promise is successfully resolved and the specified Failure callback is called when this Promise is resolved with a failure.

        This method returns a new Promise which is chained to this Promise. The returned Promise must be resolved when this Promise is resolved after the specified Success or Failure callback is executed. The result of the executed callback must be used to resolve the returned Promise. Multiple calls to this method can be used to create a chain of promises which are resolved in sequence.

        If this Promise is successfully resolved, the Success callback is executed and the result Promise, if any, or thrown exception is used to resolve the returned Promise from this method. If this Promise is resolved with a failure, the Failure callback is executed and the returned Promise from this method is failed.

        This method may be called at any time including before and after this Promise has been resolved.

        Resolving this Promise happens-before any registered callback is called. That is, in a registered callback, Promise.isDone() must return true and Promise.getValue() and Promise.getFailure() must not block.

        A callback may be called on a different thread than the thread which registered the callback. So the callback must be thread safe but can rely upon that the registration of the callback happens-before the registered callback is called.

        Specified by:
        then in interface Promise<T>
        Overrides:
        then in class PromiseImpl<T>
        Type Parameters:
        R - The value type associated with the returned Promise.
        Parameters:
        success - The Success callback to be called when this Promise is successfully resolved. May be null if no Success callback is required. In this case, the returned Promise must be resolved with the value null when this Promise is successfully resolved.
        failure - The Failure callback to be called when this Promise is resolved with a failure. May be null if no Failure callback is required.
        Returns:
        A new Promise which is chained to this Promise. The returned Promise must be resolved when this Promise is resolved after the specified Success or Failure callback, if any, is executed.

      • thenAccept

        public Promise<T> thenAccept​(Consumer<? super T> consumer)
        Chain a new Promise to this Promise with a Consumer callback that receives the value of this Promise when it is successfully resolved.

        The specified Consumer is called when this Promise is resolved successfully.

        This method returns a new Promise which is chained to this Promise. The returned Promise must be resolved when this Promise is resolved after the specified callback is executed. If the callback throws an exception, the returned Promise is failed with that exception. Otherwise the returned Promise is resolved with the success value from this Promise.

        This method may be called at any time including before and after this Promise has been resolved.

        Resolving this Promise happens-before any registered callback is called. That is, in a registered callback, Promise.isDone() must return true and Promise.getValue() and Promise.getFailure() must not block.

        A callback may be called on a different thread than the thread which registered the callback. So the callback must be thread safe but can rely upon that the registration of the callback happens-before the registered callback is called.

        Specified by:
        thenAccept in interface Promise<T>
        Overrides:
        thenAccept in class PromiseImpl<T>
        Parameters:
        consumer - The Consumer callback that receives the value of this Promise. Must not be null.
        Returns:
        A new Promise which is chained to this Promise. The returned Promise must be resolved when this Promise is resolved after the specified Consumer is executed.

      • filter

        public Promise<T> filter​(Predicate<? super T> predicate)
        Filter the value of this Promise.

        If this Promise is successfully resolved, the returned Promise must either be resolved with the value of this Promise, if the specified Predicate accepts that value, or failed with a NoSuchElementException, if the specified Predicate does not accept that value. If the specified Predicate throws an exception, the returned Promise must be failed with the exception.

        If this Promise is resolved with a failure, the returned Promise must be failed with that failure.

        This method may be called at any time including before and after this Promise has been resolved.

        Specified by:
        filter in interface Promise<T>
        Overrides:
        filter in class PromiseImpl<T>
        Parameters:
        predicate - The Predicate to evaluate the value of this Promise. Must not be null.
        Returns:
        A Promise that filters the value of this Promise.

      • map

        public <R> Promise<R> map​(Function<? super T,​? extends R> mapper)
        Map the value of this Promise.

        If this Promise is successfully resolved, the returned Promise must be resolved with the value of specified Function as applied to the value of this Promise. If the specified Function throws an exception, the returned Promise must be failed with the exception.

        If this Promise is resolved with a failure, the returned Promise must be failed with that failure.

        This method may be called at any time including before and after this Promise has been resolved.

        Specified by:
        map in interface Promise<T>
        Overrides:
        map in class PromiseImpl<T>
        Type Parameters:
        R - The value type associated with the returned Promise.
        Parameters:
        mapper - The Function that must map the value of this Promise to the value that must be used to resolve the returned Promise. Must not be null.
        Returns:
        A Promise that returns the value of this Promise as mapped by the specified Function.

      • flatMap

        public <R> Promise<R> flatMap​(Function<? super T,​Promise<? extends R>> mapper)
        FlatMap the value of this Promise.

        If this Promise is successfully resolved, the returned Promise must be resolved with the Promise from the specified Function as applied to the value of this Promise. If the specified Function throws an exception, the returned Promise must be failed with the exception.

        If this Promise is resolved with a failure, the returned Promise must be failed with that failure.

        This method may be called at any time including before and after this Promise has been resolved.

        Specified by:
        flatMap in interface Promise<T>
        Overrides:
        flatMap in class PromiseImpl<T>
        Type Parameters:
        R - The value type associated with the returned Promise.
        Parameters:
        mapper - The Function that must flatMap the value of this Promise to a Promise that must be used to resolve the returned Promise. Must not be null.
        Returns:
        A Promise that returns the value of this Promise as mapped by the specified Function.

      • timeout

        public Promise<T> timeout​(long millis)
        Time out the resolution of this Promise.

        If this Promise is successfully resolved before the timeout, the returned Promise is resolved with the value of this Promise. If this Promise is resolved with a failure before the timeout, the returned Promise is resolved with the failure of this Promise. If the timeout is reached before this Promise is resolved, the returned Promise is failed with a TimeoutException.

        Specified by:
        timeout in interface Promise<T>
        Overrides:
        timeout in class PromiseImpl<T>
        Parameters:
        millis - The time to wait in milliseconds. Zero and negative time is treated as an immediate timeout.
        Returns:
        A Promise that is resolved when either this Promise is resolved or the specified timeout is reached.