| /* |
| * 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; |
| |
| import java.io.IOException; |
| import java.util.NoSuchElementException; |
| import org.apache.beam.runners.dataflow.worker.util.common.worker.NativeReader; |
| import org.apache.beam.runners.dataflow.worker.windmill.Windmill; |
| import org.apache.beam.sdk.util.WindowedValue; |
| import org.apache.beam.vendor.guava.v20_0.com.google.common.base.Optional; |
| |
| /** |
| * Base class for iterators that decode messages from bundles inside a {@link Windmill.WorkItem}. |
| */ |
| public abstract class WindmillReaderIteratorBase<T> |
| extends NativeReader.NativeReaderIterator<WindowedValue<T>> { |
| private Windmill.WorkItem work; |
| private int bundleIndex = 0; |
| private int messageIndex = -1; |
| private Optional<WindowedValue<T>> current; |
| |
| protected WindmillReaderIteratorBase(Windmill.WorkItem work) { |
| this.work = work; |
| } |
| |
| @Override |
| public boolean start() throws IOException { |
| return advance(); |
| } |
| |
| @Override |
| public boolean advance() throws IOException { |
| if (bundleIndex == work.getMessageBundlesCount() |
| || messageIndex == work.getMessageBundles(bundleIndex).getMessagesCount()) { |
| current = Optional.absent(); |
| return false; |
| } |
| ++messageIndex; |
| for (; bundleIndex < work.getMessageBundlesCount(); ++bundleIndex, messageIndex = 0) { |
| Windmill.InputMessageBundle bundle = work.getMessageBundles(bundleIndex); |
| if (messageIndex < bundle.getMessagesCount()) { |
| current = Optional.of(decodeMessage(bundle.getMessages(messageIndex))); |
| return true; |
| } |
| } |
| current = Optional.absent(); |
| return false; |
| } |
| |
| protected abstract WindowedValue<T> decodeMessage(Windmill.Message message) throws IOException; |
| |
| @Override |
| public WindowedValue<T> getCurrent() throws NoSuchElementException { |
| if (!current.isPresent()) { |
| throw new NoSuchElementException(); |
| } |
| return current.get(); |
| } |
| } |