eu.stratosphere.nephele.io.RuntimeInputGate Maven / Gradle / Ivy
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* 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.nephele.io;
import java.io.IOException;
import java.util.ArrayList;
import java.util.Iterator;
import java.util.concurrent.BlockingQueue;
import java.util.concurrent.LinkedBlockingQueue;
import java.util.concurrent.atomic.AtomicReference;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import eu.stratosphere.core.io.IOReadableWritable;
import eu.stratosphere.nephele.event.task.AbstractEvent;
import eu.stratosphere.nephele.event.task.AbstractTaskEvent;
import eu.stratosphere.nephele.io.channels.AbstractInputChannel;
import eu.stratosphere.nephele.io.channels.ChannelID;
import eu.stratosphere.nephele.io.channels.bytebuffered.InMemoryInputChannel;
import eu.stratosphere.nephele.io.channels.bytebuffered.NetworkInputChannel;
import eu.stratosphere.nephele.jobgraph.JobID;
/**
* In Nephele input gates are a specialization of general gates and connect input channels and record readers. As
* channels, input gates are always parameterized to a specific type of record which they can transport. In contrast to
* output gates input gates can be associated with a {@link DistributionPattern} object which dictates the concrete
* wiring between two groups of vertices.
*
* @param The type of record that can be transported through this gate.
*/
public class RuntimeInputGate extends AbstractGate implements InputGate {
/**
* The log object used for debugging.
*/
private static final Log LOG = LogFactory.getLog(InputGate.class);
/**
* The deserializer factory used to instantiate the deserializers that construct records from byte streams.
*/
private final RecordDeserializerFactory deserializerFactory;
/**
* The list of input channels attached to this input gate.
*/
private final ArrayList> inputChannels = new ArrayList>();
/**
* Queue with indices of channels that store at least one available record.
*/
private final BlockingQueue availableChannels = new LinkedBlockingQueue();
/**
* The listener object to be notified when a channel has at least one record available.
*/
private final AtomicReference> recordAvailabilityListener = new AtomicReference>(null);
private AbstractTaskEvent currentEvent;
/**
* If the value of this variable is set to true, the input gate is closed.
*/
private boolean isClosed = false;
/**
* The channel to read from next.
*/
private int channelToReadFrom = -1;
/**
* Constructs a new runtime input gate.
*
* @param jobID
* the ID of the job this input gate belongs to
* @param gateID
* the ID of the gate
* @param deserializerFactory
* The factory used to instantiate the deserializers that construct records from byte streams.
* @param index
* the index assigned to this input gate at the {@link Environment} object
*/
public RuntimeInputGate(final JobID jobID, final GateID gateID,
final RecordDeserializerFactory deserializerFactory, final int index) {
super(jobID, gateID, index);
this.deserializerFactory = deserializerFactory;
}
/**
* Adds a new input channel to the input gate.
*
* @param inputChannel
* the input channel to be added.
*/
private void addInputChannel(AbstractInputChannel inputChannel) {
// in high DOPs, this can be a serious performance issue, as adding all channels and checking linearly has a
// quadratic complexity!
if (!this.inputChannels.contains(inputChannel)) {
this.inputChannels.add(inputChannel);
}
}
/**
* Removes the input channel with the given ID from the input gate if it exists.
*
* @param inputChannelID
* the ID of the channel to be removed
*/
public void removeInputChannel(ChannelID inputChannelID) {
for (int i = 0; i < this.inputChannels.size(); i++) {
final AbstractInputChannel inputChannel = this.inputChannels.get(i);
if (inputChannel.getID().equals(inputChannelID)) {
this.inputChannels.remove(i);
return;
}
}
if (LOG.isDebugEnabled()) {
LOG.debug("Cannot find output channel with ID " + inputChannelID + " to remove");
}
}
@Override
public boolean isInputGate() {
return true;
}
@Override
public int getNumberOfInputChannels() {
return this.inputChannels.size();
}
@Override
public AbstractInputChannel getInputChannel(int pos) {
return this.inputChannels.get(pos);
}
@Override
public NetworkInputChannel createNetworkInputChannel(final InputGate inputGate, final ChannelID channelID,
final ChannelID connectedChannelID) {
final NetworkInputChannel enic = new NetworkInputChannel(inputGate, this.inputChannels.size(),
this.deserializerFactory.createDeserializer(), channelID, connectedChannelID);
addInputChannel(enic);
return enic;
}
@Override
public InMemoryInputChannel createInMemoryInputChannel(final InputGate inputGate, final ChannelID channelID,
final ChannelID connectedChannelID) {
final InMemoryInputChannel eimic = new InMemoryInputChannel(inputGate, this.inputChannels.size(),
this.deserializerFactory.createDeserializer(), channelID, connectedChannelID);
addInputChannel(eimic);
return eimic;
}
@Override
public InputChannelResult readRecord(T target) throws IOException, InterruptedException {
if (this.channelToReadFrom == -1) {
if (this.isClosed()) {
return InputChannelResult.END_OF_STREAM;
}
if (Thread.interrupted()) {
throw new InterruptedException();
}
this.channelToReadFrom = waitForAnyChannelToBecomeAvailable();
}
InputChannelResult result = this.getInputChannel(this.channelToReadFrom).readRecord(target);
switch (result) {
case INTERMEDIATE_RECORD_FROM_BUFFER: // full record and we can stay on the same channel
return InputChannelResult.INTERMEDIATE_RECORD_FROM_BUFFER;
case LAST_RECORD_FROM_BUFFER: // full record, but we must switch the channel afterwards
this.channelToReadFrom = -1;
return InputChannelResult.LAST_RECORD_FROM_BUFFER;
case END_OF_SUPERSTEP:
this.channelToReadFrom = -1;
return InputChannelResult.END_OF_SUPERSTEP;
case TASK_EVENT: // task event
this.currentEvent = this.getInputChannel(this.channelToReadFrom).getCurrentEvent();
this.channelToReadFrom = -1; // event always marks a unit as consumed
return InputChannelResult.TASK_EVENT;
case NONE: // internal event or an incomplete record that needs further chunks
// the current unit is exhausted
this.channelToReadFrom = -1;
return InputChannelResult.NONE;
case END_OF_STREAM: // channel is done
this.channelToReadFrom = -1;
return isClosed() ? InputChannelResult.END_OF_STREAM : InputChannelResult.NONE;
default: // silence the compiler
throw new RuntimeException();
}
}
@Override
public AbstractTaskEvent getCurrentEvent() {
AbstractTaskEvent e = this.currentEvent;
this.currentEvent = null;
return e;
}
@Override
public void notifyRecordIsAvailable(int channelIndex) {
this.availableChannels.add(Integer.valueOf(channelIndex));
RecordAvailabilityListener listener = this.recordAvailabilityListener.get();
if (listener != null) {
listener.reportRecordAvailability(this);
}
}
/**
* This method returns the index of a channel which has at least
* one record available. The method may block until at least one
* channel has become ready.
*
* @return the index of the channel which has at least one record available
*/
public int waitForAnyChannelToBecomeAvailable() throws InterruptedException {
return this.availableChannels.take().intValue();
}
@Override
public boolean isClosed() throws IOException, InterruptedException {
if (this.isClosed) {
return true;
}
for (int i = 0; i < this.getNumberOfInputChannels(); i++) {
final AbstractInputChannel inputChannel = this.inputChannels.get(i);
if (!inputChannel.isClosed()) {
return false;
}
}
this.isClosed = true;
return true;
}
@Override
public void close() throws IOException, InterruptedException {
for (int i = 0; i < this.getNumberOfInputChannels(); i++) {
final AbstractInputChannel inputChannel = this.inputChannels.get(i);
inputChannel.close();
}
}
@Override
public String toString() {
return "Input " + super.toString();
}
@Override
public void publishEvent(AbstractEvent event) throws IOException, InterruptedException {
// Copy event to all connected channels
final Iterator> it = this.inputChannels.iterator();
while (it.hasNext()) {
it.next().transferEvent(event);
}
}
/**
* Returns the {@link RecordDeserializerFactory} used by this input gate.
*
* @return The {@link RecordDeserializerFactory} used by this input gate.
*/
public RecordDeserializerFactory getRecordDeserializerFactory() {
return this.deserializerFactory;
}
@Override
public void releaseAllChannelResources() {
final Iterator> it = this.inputChannels.iterator();
while (it.hasNext()) {
it.next().releaseAllResources();
}
}
@Override
public void registerRecordAvailabilityListener(final RecordAvailabilityListener listener) {
if (!this.recordAvailabilityListener.compareAndSet(null, listener)) {
throw new IllegalStateException(this.recordAvailabilityListener
+ " is already registered as a record availability listener");
}
}
public void notifyDataUnitConsumed(int channelIndex) {
this.channelToReadFrom = -1;
}
}
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