org.opendaylight.infrautils.utils.concurrent.ListenableToCompletableFutureWrapper.java Source code

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Here is the source code for org.opendaylight.infrautils.utils.concurrent.ListenableToCompletableFutureWrapper.java

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/*
 * Copyright (c) 2017 Red Hat, Inc. and others. All rights reserved.
 *
 * This program and the accompanying materials are made available under the
 * terms of the Eclipse Public License v1.0 which accompanies this distribution,
 * and is available at http://www.eclipse.org/legal/epl-v10.html
 */
package org.opendaylight.infrautils.utils.concurrent;

import static java.util.Objects.requireNonNull;

import com.google.common.util.concurrent.FutureCallback;
import com.google.common.util.concurrent.Futures;
import com.google.common.util.concurrent.ListenableFuture;
import com.google.common.util.concurrent.MoreExecutors;
import edu.umd.cs.findbugs.annotations.SuppressFBWarnings;
import java.util.concurrent.CompletableFuture;
import java.util.concurrent.CompletionStage;

// package local, not public
final class ListenableToCompletableFutureWrapper<V> extends CompletableFuture<V> implements FutureCallback<V> {

    // This implementation is inspired by a spotify/futures-extra's class of the same name
    // remixed with https://blog.krecan.net/2014/06/11/converting-listenablefutures-to-completablefutures-and-back/

    public static <T> CompletionStage<T> create(ListenableFuture<T> guavaListenableFuture) {
        ListenableToCompletableFutureWrapper<T> instance = new ListenableToCompletableFutureWrapper<>(
                guavaListenableFuture);
        Futures.addCallback(guavaListenableFuture, instance, MoreExecutors.directExecutor());
        return instance;
    }

    private final ListenableFuture<V> guavaListenableFuture;

    private ListenableToCompletableFutureWrapper(ListenableFuture<V> guavaListenableFuture) {
        this.guavaListenableFuture = requireNonNull(guavaListenableFuture, "guavaListenableFuture");
    }

    @Override
    @SuppressFBWarnings("NP_PARAMETER_MUST_BE_NONNULL_BUT_MARKED_AS_NULLABLE") // https://github.com/findbugsproject/findbugs/issues/79
    public void onSuccess(V result) {
        complete(result);
    }

    @Override
    public void onFailure(Throwable throwable) {
        completeExceptionally(throwable);
    }

    @Override
    public boolean cancel(boolean mayInterruptIfRunning) {
        boolean result = guavaListenableFuture.cancel(mayInterruptIfRunning);
        super.cancel(mayInterruptIfRunning);
        return result;
    }

}