| /* |
| * 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.dataflow.worker.util.common.worker; |
| |
| import static org.apache.beam.vendor.guava.v20_0.com.google.common.base.Preconditions.checkNotNull; |
| |
| import org.apache.beam.runners.dataflow.worker.util.common.ForwardingReiterator; |
| import org.apache.beam.sdk.util.common.Reiterator; |
| |
| /** |
| * Implements a {@link Reiterator} that uses a {@link ProgressTrackerGroup.Tracker ProgressTracker} |
| * to track how far it's gotten through some base {@code Reiterator}. {@link |
| * ProgressTrackingReiterator#copy} copies the {@code ProgressTracker}, allowing for an independent |
| * progress state. |
| * |
| * @param <T> the type of the elements of this iterator |
| */ |
| public final class ProgressTrackingReiterator<T> extends ForwardingReiterator<T> { |
| private ProgressTracker<T> tracker; |
| |
| public ProgressTrackingReiterator(Reiterator<T> base, ProgressTracker<T> tracker) { |
| super(base); |
| this.tracker = checkNotNull(tracker); |
| } |
| |
| @Override |
| public T next() { |
| T result = super.next(); |
| tracker.saw(result); |
| return result; |
| } |
| |
| @Override |
| protected ProgressTrackingReiterator<T> clone() { |
| ProgressTrackingReiterator<T> result = (ProgressTrackingReiterator<T>) super.clone(); |
| result.tracker = tracker.copy(); |
| return result; |
| } |
| } |