Package com.google.api.gax.longrunning

Class OperationFutureImpl<ResponseT,​MetadataT>

  • All Implemented Interfaces:
    com.google.api.core.ApiFuture<ResponseT>, OperationFuture<ResponseT,​MetadataT>, java.util.concurrent.Future<ResponseT>
    @InternalApi
public final class OperationFutureImpl<ResponseT,​MetadataT>
extends java.lang.Object
implements OperationFuture<ResponseT,​MetadataT>
    An ApiFuture which tracks polling of a service. The polling is done periodically, based on the TimedRetryAlgorithm.

    This class is thread-safe.

    This is public only for technical reasons, for advanced usage.

    • Method Detail

      • addListener

        public void addListener​(java.lang.Runnable listener,
                        java.util.concurrent.Executor executor)
        Specified by:
        addListener in interface com.google.api.core.ApiFuture<ResponseT>

      • cancel

        public boolean cancel​(boolean mayInterruptIfRunning)
        Specified by:
        cancel in interface java.util.concurrent.Future<ResponseT>

      • isCancelled

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

      • isDone

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

      • get

        public ResponseT get()
              throws java.lang.InterruptedException,
                     java.util.concurrent.ExecutionException
        Specified by:
        get in interface java.util.concurrent.Future<ResponseT>
        Throws:
        java.lang.InterruptedException
        java.util.concurrent.ExecutionException

      • get

        public ResponseT get​(long timeout,
                     java.util.concurrent.TimeUnit unit)
              throws java.lang.InterruptedException,
                     java.util.concurrent.ExecutionException,
                     java.util.concurrent.TimeoutException
        Specified by:
        get in interface java.util.concurrent.Future<ResponseT>
        Throws:
        java.lang.InterruptedException
        java.util.concurrent.ExecutionException
        java.util.concurrent.TimeoutException

      • getName

        public java.lang.String getName()
                         throws java.util.concurrent.ExecutionException,
                                java.lang.InterruptedException
        Description copied from interface: OperationFuture
        Returns the value of the name of the operation from the initial operation object returned from the initial call to start the operation. Blocks if the initial call to start the operation hasn't returned yet.
        Specified by:
        getName in interface OperationFuture<ResponseT,​MetadataT>
        Throws:
        java.util.concurrent.ExecutionException
        java.lang.InterruptedException

      • peekMetadata

        public com.google.api.core.ApiFuture<MetadataT> peekMetadata()
        Description copied from interface: OperationFuture
        Peeks at the metadata of the operation tracked by this OperationFuture. If the initial future hasn't completed yet this method returns null, otherwise it returns the latest metadata returned from the server (i.e. either initial call metadata or the metadata received from the latest completed poll iteration).

        If not null, the returned result is guaranteed to be an already completed future, so Future.isDone() will always be true and Future.get() will always be non-blocking.

        Note, some APIs may return null in metadata response message. In such cases this method may return a non-null future whose get() method will return null. This behavior is API specific an should be considered a valid case, which indicates that the recent poll request has completed, but no specific metadata was provided by the server (i.e. most probably providing metadata for an intermediate result is not supported by the server).

        This method should be used to check operation progress without blocking current thread. Since this method returns metadata from the latest completed poll, it is potentially slightly stale compared to the most recent data. To get the most recent data and/or get notified when the current scheduled poll request completes use the OperationFuture.getMetadata() method instead.

        If this operation future is completed, this method always returns the metadata from the last poll request (which completed the operation future).

        If this operation future failed, this method may (depending on the failure type) return a non-failing future, representing the metadata from the last poll request (which failed the operation future).

        If this operation future was cancelled, this method returns a canceled metatata future as well.

        In general this method behaves similarly to RetryingFuture.peekAttemptResult().

        Specified by:
        peekMetadata in interface OperationFuture<ResponseT,​MetadataT>

      • getMetadata

        public com.google.api.core.ApiFuture<MetadataT> getMetadata()
        Description copied from interface: OperationFuture
        Gets the metadata of the operation tracked by this OperationFuture. This method returns the current poll metadata result (or the initial call metadata if it hasn't completed yet). The returned future completes once the current scheduled poll request (or the initial request if it hasn't completed yet) is executed and response is received from the server. The time when the polling request is executed is determined by the underlying polling algorithm.

        Adding direct executor (same thread) callbacks to the future returned by this method is strongly not recommended, since the future is resolved under retrying future's internal lock and may affect the operation polling process. Adding separate thread callbacks is ok.

        Note, some APIs may return null in metadata response message. In such cases this method may return a non-null future whose get() method will return null. This behavior is API specific an should be considered a valid case, which indicates that the recent poll request has completed, but no specific metadata was provided by the server. (i.e. most probably providing metadata for an intermediate result is not supported by the server).

        In most cases this method returns a future which is not completed yet, so calling Future.get() is a potentially blocking operation. To get metadata without blocking the current thread use the OperationFuture.peekMetadata() method instead.

        If this operation future is completed, this method always returns the metadata from the last poll request (which completed the operation future).

        If this operation future failed, this method may (depending on the failure type) return a non-failing future, representing the metadata from the last poll request (which failed the operation future).

        If this operation future was cancelled, this method returns a canceled metatata future as well.

        In general this method behaves similarly to RetryingFuture.getAttemptResult().

        Specified by:
        getMetadata in interface OperationFuture<ResponseT,​MetadataT>