org.apache.flink.runtime.operators.shipping.RecordOutputCollector Maven / Gradle / Ivy

/*
 * 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.flink.runtime.operators.shipping;

import java.io.IOException;
import java.util.Arrays;
import java.util.Collections;
import java.util.List;

import org.apache.flink.runtime.io.network.api.writer.RecordWriter;
import org.apache.flink.types.Record;
import org.apache.flink.util.Collector;

/**
 * The OutputCollector collects {@link Record}s, and emits the pair to a set of Nephele {@link RecordWriter}s.
 * The OutputCollector tracks to which writers a deep-copy must be given and which not.
 */
public class RecordOutputCollector implements Collector
{
	// list of writers
	protected RecordWriter[] writers;

	/**
	 * Initializes the output collector with a set of writers.
	 * To specify for a writer that it must be fed with a deep-copy, set the bit in the copy flag bit mask to 1 that
	 * corresponds to the position of the writer within the {@link List}.
	 *
	 * @param writers List of all writers.
	 */
	@SuppressWarnings("unchecked")
	public RecordOutputCollector(List> writers) {

		this.writers = (RecordWriter[]) writers.toArray(new RecordWriter[writers.size()]);
	}

	/**
	 * Adds a writer to the OutputCollector.
	 *
	 * @param writer The writer to add.
	 */
	@SuppressWarnings("unchecked")
	public void addWriter(RecordWriter writer)
	{
		// avoid using the array-list here to reduce one level of object indirection
		if (this.writers == null) {
			this.writers = new RecordWriter[] {writer};
		}
		else {
			RecordWriter[] ws = new RecordWriter[this.writers.length + 1];
			System.arraycopy(this.writers, 0, ws, 0, this.writers.length);
			ws[this.writers.length] = writer;
			this.writers = ws;
		}
	}

	/**
	 * Collects a {@link Record}, and emits it to all writers.
	 * Writers which require a deep-copy are fed with a copy.
	 */
	@Override
	public void collect(Record record)
	{
		try {
			for (int i = 0; i < writers.length; i++) {
				this.writers[i].emit(record);
			}
		}
		catch (IOException e) {
			throw new RuntimeException("Emitting the record caused an I/O exception: " + e.getMessage(), e);
		}
		catch (InterruptedException e) {
			throw new RuntimeException("Emitting the record was interrupted: " + e.getMessage(), e);
		}
	}

	@Override
	public void close() {
		for (RecordWriter writer : writers) {
			try {
				writer.flush();
			} catch (IOException e) {
				throw new RuntimeException(e.getMessage(), e);
			}
		}
	}

	/**
	 * List of writers that are associated with this output collector
	 * @return list of writers
	 */
	public List> getWriters() {
		return Collections.unmodifiableList(Arrays.asList(writers));
	}
}