Package org.threadly.concurrent.future

Class ImmediateResultListenableFuture<T>

  • Type Parameters:
    T - The result object type returned by this future
    All Implemented Interfaces:
    java.util.concurrent.Future<T>, ListenableFuture<T>
    public class ImmediateResultListenableFuture<T>
extends java.lang.Object
    Completed implementation of ListenableFuture that will immediately return a result. Meaning listeners added will immediately be ran/executed, FutureCallback's will immediately get called with the result provided, and get() calls will never block.
    Since:
    1.3.0

    • Constructor Detail

      • ImmediateResultListenableFuture

        public ImmediateResultListenableFuture​(T result)
        Constructs a completed future that will return the provided result.
        Parameters:
        result - Result that is returned by future

    • Method Detail

      • isCompletedExceptionally

        public boolean isCompletedExceptionally()
        Description copied from interface: ListenableFuture
        Returns true if the future is both done and has completed with an error or was canceled. If this returns true the Throwable responsible for the error can be retrieved using ListenableFuture.getFailure();
        Returns:
        true if this ListenableFuture completed by a thrown Exception or was canceled

      • mapFailure

        public <TT extends java.lang.Throwable> ListenableFuture<T> mapFailure​(java.lang.Class<TT> throwableType,
                                                                       java.util.function.Function<? super TT,​? extends T> mapper)
        Description copied from interface: ListenableFuture
        Similar to ListenableFuture.throwMap(Function) except this mapper will only be invoked when the future is in a failure state (from either the original computation or an earlier mapper throwing an exception). If this future does resolve in a failure state, and that exception class matches the one provided here. The mapper function will then be provided that throwable, it can then map that throwable back into a result (perhaps an Optional), or re-throw either the same or a different exception keep the future in a failure state. If the future completes with a normal result, this mapper will be ignored, and the result will be forwarded on without invoking this mapper.
        Specified by:
        mapFailure in interface ListenableFuture<T>
        Type Parameters:
        TT - The type of throwable that should be handled
        Parameters:
        throwableType - The class referencing to the type of throwable this mapper handles
        mapper - The mapper to convert a thrown exception to either a result or thrown exception
        Returns:
        A ListenableFuture that will resolve after the mapper is considered

      • mapFailure

        public <TT extends java.lang.Throwable> ListenableFuture<T> mapFailure​(java.lang.Class<TT> throwableType,
                                                                       java.util.function.Function<? super TT,​? extends T> mapper,
                                                                       java.util.concurrent.Executor executor)
        Description copied from interface: ListenableFuture
        Similar to ListenableFuture.throwMap(Function, Executor) except this mapper will only be invoked when the future is in a failure state (from either the original computation or an earlier mapper throwing an exception). If this future does resolve in a failure state, and that exception class matches the one provided here. The mapper function will then be provided that throwable, it can then map that throwable back into a result (perhaps an Optional), or re-throw either the same or a different exception keep the future in a failure state. If the future completes with a normal result, this mapper will be ignored, and the result will be forwarded on without invoking this mapper.
        Specified by:
        mapFailure in interface ListenableFuture<T>
        Type Parameters:
        TT - The type of throwable that should be handled
        Parameters:
        throwableType - The class referencing to the type of throwable this mapper handles
        mapper - The mapper to convert a thrown exception to either a result or thrown exception
        executor - Executor to invoke mapper function on, or null to invoke on this thread or future complete thread (depending on future state)
        Returns:
        A ListenableFuture that will resolve after the mapper is considered

      • mapFailure

        public <TT extends java.lang.Throwable> ListenableFuture<T> mapFailure​(java.lang.Class<TT> throwableType,
                                                                       java.util.function.Function<? super TT,​? extends T> mapper,
                                                                       java.util.concurrent.Executor executor,
                                                                       ListenableFuture.ListenerOptimizationStrategy optimizeExecution)
        Description copied from interface: ListenableFuture
        Similar to ListenableFuture.throwMap(Function, Executor, ListenerOptimizationStrategy) except this mapper will only be invoked when the future is in a failure state (from either the original computation or an earlier mapper throwing an exception). If this future does resolve in a failure state, and that exception class matches the one provided here. The mapper function will then be provided that throwable, it can then map that throwable back into a result perhaps an Optional), or re-throw either the same or a different exception keep the future in a failure state. If the future completes with a normal result, this mapper will be ignored, and the result will be forwarded on without invoking this mapper.
        Specified by:
        mapFailure in interface ListenableFuture<T>
        Type Parameters:
        TT - The type of throwable that should be handled
        Parameters:
        throwableType - The class referencing to the type of throwable this mapper handles
        mapper - The mapper to convert a thrown exception to either a result or thrown exception
        executor - Executor to invoke mapper function on, or null to invoke on this thread or future complete thread (depending on future state)
        optimizeExecution - true to avoid listener queuing for execution if already on the desired pool
        Returns:
        A ListenableFuture that will resolve after the mapper is considered

      • flatMapFailure

        public <TT extends java.lang.Throwable> ListenableFuture<T> flatMapFailure​(java.lang.Class<TT> throwableType,
                                                                           java.util.function.Function<? super TT,​ListenableFuture<T>> mapper)
        Description copied from interface: ListenableFuture
        Similar to ListenableFuture.mapFailure(Class, Function) except that this mapper function returns a ListenableFuture if it needs to map the Throwable / failure into a result or another failure. The mapper function can return a Future that will (or may) provide a result, or it can provide a future that will result in the same or another failure. Similar to ListenableFuture.mapFailure(Class, Function) the mapper can also throw an exception directly.
        Specified by:
        flatMapFailure in interface ListenableFuture<T>
        Type Parameters:
        TT - The type of throwable that should be handled
        Parameters:
        throwableType - The class referencing to the type of throwable this mapper handles
        mapper - Function to invoke in order to transform the futures result
        Returns:
        A ListenableFuture that will resolve after the mapper is considered

      • flatMapFailure

        public <TT extends java.lang.Throwable> ListenableFuture<T> flatMapFailure​(java.lang.Class<TT> throwableType,
                                                                           java.util.function.Function<? super TT,​ListenableFuture<T>> mapper,
                                                                           java.util.concurrent.Executor executor)
        Description copied from interface: ListenableFuture
        Similar to ListenableFuture.mapFailure(Class, Function, Executor) except that this mapper function returns a ListenableFuture if it needs to map the Throwable / failure into a result or another failure. The mapper function can return a Future that will (or may) provide a result, or it can provide a future that will result in the same or another failure. Similar to ListenableFuture.mapFailure(Class, Function, Executor) the mapper can also throw an exception directly.
        Specified by:
        flatMapFailure in interface ListenableFuture<T>
        Type Parameters:
        TT - The type of throwable that should be handled
        Parameters:
        throwableType - The class referencing to the type of throwable this mapper handles
        mapper - Function to invoke in order to transform the futures result
        executor - Executor to invoke mapper function on, or null to invoke on this thread or future complete thread (depending on future state)
        Returns:
        A ListenableFuture that will resolve after the mapper is considered

      • callback

        public ListenableFuture<T> callback​(FutureCallback<? super T> callback,
                                    java.util.concurrent.Executor executor,
                                    ListenableFuture.ListenerOptimizationStrategy optimize)
        Description copied from interface: ListenableFuture
        Add a FutureCallback to be called once the future has completed. If the future has already finished, this will be called immediately.

        If the provided Executor is null, the callback will execute on the thread which computed the original future (once it is done). If the future has already completed, the callback will execute immediately on the thread which is adding the callback.

        Caution should be used when choosing to optimize the listener execution. If the listener is complex, or wanting to be run concurrent, this optimization could prevent that. In addition it will prevent other listeners from potentially being invoked until it completes. However if the listener is small / fast, this can provide significant performance gains. It should also be known that not all ListenableFuture implementations may be able to do such an optimization. Please see ListenableFuture.ListenerOptimizationStrategy javadocs for more specific details of what optimizations are available.

        If you only care about the success result case please see ListenableFuture.resultCallback(Consumer, Executor, ListenerOptimizationStrategy) or conversely if you only want to be invoked for failure cases please see ListenableFuture.failureCallback(Consumer, Executor, ListenerOptimizationStrategy).

        Parameters:
        callback - to be invoked when the computation is complete
        executor - Executor the callback should be ran on, or null
        optimize - true to avoid listener queuing for execution if already on the desired pool
        Returns:
        Exactly this instance to add more callbacks or other functional operations

      • resultCallback

        public ListenableFuture<T> resultCallback​(java.util.function.Consumer<? super T> callback,
                                          java.util.concurrent.Executor executor,
                                          ListenableFuture.ListenerOptimizationStrategy optimize)
        Description copied from interface: ListenableFuture
        Add a Consumer to be called once the future has completed. If the future has already finished, this will be called immediately. Assuming the future has completed without error, the result will be provided to the Consumer, otherwise it will go un-invoked.

        If the provided Executor is null, the callback will execute on the thread which computed the original future (once it is done). If the future has already completed, the callback will execute immediately on the thread which is adding the callback.

        Caution should be used when choosing to optimize the listener execution. If the listener is complex, or wanting to be run concurrent, this optimization could prevent that. In addition it will prevent other listeners from potentially being invoked until it completes. However if the listener is small / fast, this can provide significant performance gains. It should also be known that not all ListenableFuture implementations may be able to do such an optimization. Please see ListenableFuture.ListenerOptimizationStrategy javadocs for more specific details of what optimizations are available.

        Parameters:
        callback - to be invoked when the computation is complete
        executor - Executor the callback should be ran on, or null
        optimize - true to avoid listener queuing for execution if already on the desired pool
        Returns:
        Exactly this instance to add more callbacks or other functional operations

      • failureCallback

        public ListenableFuture<T> failureCallback​(java.util.function.Consumer<java.lang.Throwable> callback,
                                           java.util.concurrent.Executor executor,
                                           ListenableFuture.ListenerOptimizationStrategy optimize)
        Description copied from interface: ListenableFuture
        Add a Consumer to be called once the future has completed. If the future has already finished, this will be called immediately. Assuming the future has completed with an error, the Throwable will be provided to the Consumer, otherwise if no error occurred, the callback will go un-invoked.

        If the provided Executor is null, the callback will execute on the thread which computed the original future (once it is done). If the future has already completed, the callback will execute immediately on the thread which is adding the callback.

        Caution should be used when choosing to optimize the listener execution. If the listener is complex, or wanting to be run concurrent, this optimization could prevent that. In addition it will prevent other listeners from potentially being invoked until it completes. However if the listener is small / fast, this can provide significant performance gains. It should also be known that not all ListenableFuture implementations may be able to do such an optimization. Please see ListenableFuture.ListenerOptimizationStrategy javadocs for more specific details of what optimizations are available.

        Parameters:
        callback - to be invoked when the computation is complete
        executor - Executor the callback should be ran on, or null
        optimize - true to avoid listener queuing for execution if already on the desired pool
        Returns:
        Exactly this instance to add more callbacks or other functional operations

      • get

        public T get()

      • get

        public T get​(long timeout,
             java.util.concurrent.TimeUnit unit)

      • getFailure

        public java.lang.Throwable getFailure()
        Description copied from interface: ListenableFuture
        Similar to Future.get() except instead of providing a result, this will provide a thrown exception if ListenableFuture.isCompletedExceptionally() returns true. If the future has not completed yet this function will block until completion. If the future completed normally, this will return null.
        Returns:
        Throwable thrown in computing the future or null if completed normally

      • getFailure

        public java.lang.Throwable getFailure​(long timeout,
                                      java.util.concurrent.TimeUnit unit)
        Description copied from interface: ListenableFuture
        Similar to Future.get(long, TimeUnit) except instead of providing a result, this will provide a thrown exception if ListenableFuture.isCompletedExceptionally() returns true. If the future has not completed yet this function will block until completion. If the future completed normally, this will return null.
        Parameters:
        timeout - The maximum time to wait
        unit - The time unit of the timeout argument
        Returns:
        Throwable thrown in computing the future or null if completed normally

      • isDone

        public boolean isDone()
        Specified by:
        isDone in interface java.util.concurrent.Future<T>

      • listener

        public ListenableFuture<T> listener​(java.lang.Runnable listener)
        Description copied from interface: ListenableFuture
        Add a listener to be called once the future has completed. If the future has already finished, this will be called immediately.

        The listener from this call will execute on the same thread the result was produced on, or on the adding thread if the future is already complete. If the runnable has high complexity, consider using ListenableFuture.listener(Runnable, Executor).

        Specified by:
        listener in interface ListenableFuture<T>
        Parameters:
        listener - the listener to run when the computation is complete
        Returns:
        Exactly this instance to add more listeners or other functional operations

      • listener

        public ListenableFuture<T> listener​(java.lang.Runnable listener,
                                    java.util.concurrent.Executor executor,
                                    ListenableFuture.ListenerOptimizationStrategy optimize)
        Description copied from interface: ListenableFuture
        Add a listener to be called once the future has completed. If the future has already finished, this will be called immediately.

        If the provided Executor is null, the listener will execute on the thread which computed the original future (once it is done). If the future has already completed, the listener will execute immediately on the thread which is adding the listener.

        Caution should be used when choosing to optimize the listener execution. If the listener is complex, or wanting to be run concurrent, this optimization could prevent that. In addition it will prevent other listeners from potentially being invoked until it completes. However if the listener is small / fast, this can provide significant performance gains. It should also be known that not all ListenableFuture implementations may be able to do such an optimization. Please see ListenableFuture.ListenerOptimizationStrategy javadocs for more specific details of what optimizations are available.

        Specified by:
        listener in interface ListenableFuture<T>
        Parameters:
        listener - the listener to run when the computation is complete
        executor - Executor the listener should be ran on, or null
        optimize - true to avoid listener queuing for execution if already on the desired pool
        Returns:
        Exactly this instance to add more listeners or other functional operations

      • getRunningStackTrace

        public java.lang.StackTraceElement[] getRunningStackTrace()
        Description copied from interface: ListenableFuture
        A best effort to return the stack trace for for the executing thread of either this future, or a future which this depends on through the use of ListenableFuture.map(Function) or similar functions. If there is no thread executing the future yet, or the future has already completed, then this will return null.

        This is done without locking (though generating a stack trace still requires a JVM safe point), so the resulting stack trace is NOT guaranteed to be accurate. In most cases (particularly when blocking) this should be accurate though.

        Specified by:
        getRunningStackTrace in interface ListenableFuture<T>
        Returns:
        The stack trace currently executing the future, or null if unavailable

      • cancel

        public boolean cancel​(boolean mayInterruptIfRunning)
        This has no effect in this implementation, as this future can not be canceled.
        Specified by:
        cancel in interface java.util.concurrent.Future<T>
        Parameters:
        mayInterruptIfRunning - will be ignored
        Returns:
        will always return false, as this future can't be canceled

      • isCancelled

        public boolean isCancelled()
        Specified by:
        isCancelled in interface java.util.concurrent.Future<T>