com.spotify.scio.extra.transforms.GuavaAsyncDoFn.java Source code

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Here is the source code for com.spotify.scio.extra.transforms.GuavaAsyncDoFn.java

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/*
 * Copyright 2017 Spotify AB.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing,
 * software distributed under the License is distributed on an
 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
 * KIND, either express or implied.  See the License for the
 * specific language governing permissions and limitations
 * under the License.
 */

package com.spotify.scio.extra.transforms;

import com.google.common.util.concurrent.FutureCallback;
import com.google.common.util.concurrent.Futures;
import com.google.common.util.concurrent.ListenableFuture;
import org.apache.beam.sdk.transforms.DoFn;

import javax.annotation.Nullable;
import java.util.concurrent.ExecutionException;
import java.util.function.Function;

/**
 * A {@link DoFn} that handles asynchronous requests to an external service that returns Guava
 * {@link ListenableFuture}s.
 */
public abstract class GuavaAsyncDoFn<InputT, OutputT, ResourceT>
        extends BaseAsyncDoFn<InputT, OutputT, ResourceT, ListenableFuture<OutputT>> {
    @Override
    protected void waitForFutures(Iterable<ListenableFuture<OutputT>> futures)
            throws InterruptedException, ExecutionException {
        Futures.allAsList(futures).get();
    }

    @Override
    protected ListenableFuture<OutputT> addCallback(ListenableFuture<OutputT> future,
            Function<OutputT, Void> onSuccess, Function<Throwable, Void> onFailure) {
        Futures.addCallback(future, new FutureCallback<OutputT>() {
            @Override
            public void onSuccess(@Nullable OutputT result) {
                onSuccess.apply(result);
            }

            @Override
            public void onFailure(Throwable t) {
                onFailure.apply(t);
            }
        });
        return future;
    }
}