/***********************************************************************************************************************
* 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.io;
import java.io.EOFException;
import java.io.IOException;
import java.util.List;
import java.util.concurrent.LinkedBlockingQueue;
import eu.stratosphere.api.common.typeutils.TypeSerializer;
import eu.stratosphere.core.memory.MemorySegment;
import eu.stratosphere.nephele.services.iomanager.BlockChannelReader;
import eu.stratosphere.nephele.services.iomanager.Channel;
import eu.stratosphere.nephele.services.iomanager.ChannelReaderInputView;
import eu.stratosphere.nephele.services.iomanager.IOManager;
import eu.stratosphere.util.MutableObjectIterator;
/**
* A simple iterator over the input read though an I/O channel.
*
*/
public class ChannelReaderInputViewIterator<E> implements MutableObjectIterator<E>
{
private final ChannelReaderInputView inView;
private final TypeSerializer<E> accessors;
private final List<MemorySegment> freeMemTarget;
public ChannelReaderInputViewIterator(IOManager ioAccess, Channel.ID channel, List<MemorySegment> segments,
List<MemorySegment> freeMemTarget, TypeSerializer<E> accessors, int numBlocks)
throws IOException
{
this(ioAccess, channel, new LinkedBlockingQueue<MemorySegment>(), segments, freeMemTarget, accessors, numBlocks);
}
public ChannelReaderInputViewIterator(IOManager ioAccess, Channel.ID channel, LinkedBlockingQueue<MemorySegment> returnQueue,
List<MemorySegment> segments, List<MemorySegment> freeMemTarget, TypeSerializer<E> accessors, int numBlocks)
throws IOException
{
this(ioAccess.createBlockChannelReader(channel, returnQueue), returnQueue,
segments, freeMemTarget, accessors, numBlocks);
}
public ChannelReaderInputViewIterator(BlockChannelReader reader, LinkedBlockingQueue<MemorySegment> returnQueue,
List<MemorySegment> segments, List<MemorySegment> freeMemTarget, TypeSerializer<E> accessors, int numBlocks)
throws IOException
{
this.accessors = accessors;
this.freeMemTarget = freeMemTarget;
this.inView = new ChannelReaderInputView(reader, segments, numBlocks, false);
}
public ChannelReaderInputViewIterator(ChannelReaderInputView inView, List<MemorySegment> freeMemTarget, TypeSerializer<E> accessors)
{
this.inView = inView;
this.freeMemTarget = freeMemTarget;
this.accessors = accessors;
}
@Override
public E next(E reuse) throws IOException
{
try {
return this.accessors.deserialize(reuse, this.inView);
} catch (EOFException eofex) {
final List<MemorySegment> freeMem = this.inView.close();
if (this.freeMemTarget != null) {
this.freeMemTarget.addAll(freeMem);
}
return null;
}
}
}