/***********************************************************************************************************************
 * Copyright (C) 2010-2013 by the Stratosphere project (http://stratosphere.eu)
 *
 * 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 eu.stratosphere.pact.runtime.iterative.io;

import java.io.IOException;

import eu.stratosphere.api.common.typeutils.TypeSerializer;
import eu.stratosphere.core.memory.DataOutputView;
import eu.stratosphere.util.Collector;

/**
 * A {@link Collector} to update the iteration workset (partial solution for bulk iterations).
 * <p/>
 * The records are written to a {@link DataOutputView} to allow in-memory data exchange.
 */
public class WorksetUpdateOutputCollector<T> implements Collector<T> {

	private final TypeSerializer<T> serializer;

	private final DataOutputView outputView;

	private long elementsCollected;

	private Collector<T> delegate;

	public WorksetUpdateOutputCollector(DataOutputView outputView, TypeSerializer<T> serializer) {
		this(outputView, serializer, null);
	}

	public WorksetUpdateOutputCollector(DataOutputView outputView, TypeSerializer<T> serializer, Collector<T> delegate) {
		this.outputView = outputView;
		this.serializer = serializer;
		this.delegate = delegate;

		this.elementsCollected = 0;
	}

	@Override
	public void collect(T record) {
		try {
			this.serializer.serialize(record, this.outputView);

			if (delegate != null) {
				delegate.collect(record);
			}

			this.elementsCollected++;
		} catch (IOException e) {
			throw new RuntimeException("Unable to serialize the record", e);
		}
	}

	public long getElementsCollectedAndReset() {
		long elementsCollectedToReturn = elementsCollected;
		elementsCollected = 0;
		return elementsCollectedToReturn;
	}

	@Override
	public void close() {
		if (delegate != null) {
			delegate.close();
		}
	}
}