| /* |
| * Licensed to the Apache Software Foundation (ASF) under one |
| * or more contributor license agreements. See the NOTICE file |
| * distributed with this work for additional information |
| * regarding copyright ownership. The ASF licenses this file |
| * to you 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 org.apache.beam.runners.core; |
| |
| import static org.apache.beam.vendor.guava.v20_0.com.google.common.base.Preconditions.checkArgument; |
| |
| import edu.umd.cs.findbugs.annotations.SuppressFBWarnings; |
| import javax.annotation.Nullable; |
| import org.apache.beam.sdk.transforms.DoFn; |
| import org.apache.beam.sdk.transforms.reflect.DoFnInvoker; |
| import org.apache.beam.sdk.transforms.splittabledofn.RestrictionTracker; |
| import org.apache.beam.sdk.util.WindowedValue; |
| import org.joda.time.Instant; |
| |
| /** |
| * A runner-specific hook for invoking a {@link DoFn.ProcessElement} method for a splittable {@link |
| * DoFn}, in particular, allowing the runner to access the {@link RestrictionTracker}. |
| */ |
| public abstract class SplittableProcessElementInvoker<InputT, OutputT, RestrictionT, PositionT> { |
| /** Specifies how to resume a splittable {@link DoFn.ProcessElement} call. */ |
| public class Result { |
| @Nullable private final RestrictionT residualRestriction; |
| private final DoFn.ProcessContinuation continuation; |
| private final @Nullable Instant futureOutputWatermark; |
| |
| @SuppressFBWarnings( |
| value = "NP_PARAMETER_MUST_BE_NONNULL_BUT_MARKED_AS_NULLABLE", |
| justification = "Spotbugs incorrectly thinks continuation is marked @Nullable") |
| public Result( |
| @Nullable RestrictionT residualRestriction, |
| DoFn.ProcessContinuation continuation, |
| @Nullable Instant futureOutputWatermark) { |
| checkArgument(continuation != null, "continuation must not be null"); |
| this.continuation = continuation; |
| if (continuation.shouldResume()) { |
| checkArgument( |
| residualRestriction != null, |
| "residual restriction must not be null if continuation indicate it should resume"); |
| } |
| this.residualRestriction = residualRestriction; |
| this.futureOutputWatermark = futureOutputWatermark; |
| } |
| |
| /** |
| * Can be {@code null} only if {@link #getContinuation} specifies the call should not resume. |
| * However, the converse is not true: this can be non-null even if {@link #getContinuation} is |
| * {@link DoFn.ProcessContinuation#stop()}. |
| */ |
| @Nullable |
| public RestrictionT getResidualRestriction() { |
| return residualRestriction; |
| } |
| |
| public DoFn.ProcessContinuation getContinuation() { |
| return continuation; |
| } |
| |
| public @Nullable Instant getFutureOutputWatermark() { |
| return futureOutputWatermark; |
| } |
| } |
| |
| /** |
| * Invokes the {@link DoFn.ProcessElement} method using the given {@link DoFnInvoker} for the |
| * original {@link DoFn}, on the given element and with the given {@link RestrictionTracker}. |
| * |
| * @return Information on how to resume the call: residual restriction, a {@link |
| * DoFn.ProcessContinuation}, and a future output watermark. |
| */ |
| public abstract Result invokeProcessElement( |
| DoFnInvoker<InputT, OutputT> invoker, |
| WindowedValue<InputT> element, |
| RestrictionTracker<RestrictionT, PositionT> tracker); |
| } |