/***********************************************************************************************************************
* 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.jobmanager.splitassigner;
import java.util.concurrent.ConcurrentHashMap;
import java.util.concurrent.ConcurrentMap;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import eu.stratosphere.core.io.InputSplit;
import eu.stratosphere.core.io.LocatableInputSplit;
import eu.stratosphere.nephele.executiongraph.ExecutionGroupVertex;
import eu.stratosphere.nephele.executiongraph.ExecutionVertex;
import eu.stratosphere.nephele.instance.AbstractInstance;
import eu.stratosphere.nephele.template.AbstractInputTask;
import eu.stratosphere.nephele.template.AbstractInvokable;
/**
* The locatable input split assigner is a specific implementation of the {@link InputSplitAssigner} interface for
* {@link LocatableInputSplit} objects. The locatable input split assigner offers to take the storage location of the
* individual locatable input splits into account. It attempts to always assign the splits to vertices in a way that the
* data locality is preserved as well as possible.
* <p>
* This class is thread-safe.
*
*/
public final class LocatableInputSplitAssigner implements InputSplitAssigner {
/**
* The logging object which is used to report information and errors.
*/
private static final Log LOG = LogFactory.getLog(LocatableInputSplitAssigner.class);
private final ConcurrentMap<ExecutionGroupVertex, LocatableInputSplitList> vertexMap = new ConcurrentHashMap<ExecutionGroupVertex, LocatableInputSplitList>();
@Override
public void registerGroupVertex(final ExecutionGroupVertex groupVertex) {
// Do some sanity checks first
final AbstractInvokable invokable = groupVertex.getEnvironment().getInvokable();
// if (!(invokable instanceof AbstractFileInputTask)) {
// LOG.error(groupVertex.getName() + " is not an input vertex, ignoring vertex...");
// return;
// }
@SuppressWarnings("unchecked")
final AbstractInputTask<? extends InputSplit> inputTask = (AbstractInputTask<? extends InputSplit>) invokable;
if (!LocatableInputSplit.class.isAssignableFrom(inputTask.getInputSplitType())) {
LOG.error(groupVertex.getName() + " produces input splits of type " + inputTask.getInputSplitType()
+ " and cannot be handled by this split assigner");
return;
}
// Ignore vertices that do not produce splits
final InputSplit[] inputSplits = groupVertex.getInputSplits();
if (inputSplits == null) {
return;
}
if (inputSplits.length == 0) {
return;
}
final LocatableInputSplitList splitStore = new LocatableInputSplitList();
if (this.vertexMap.putIfAbsent(groupVertex, splitStore) != null) {
LOG.error(groupVertex.getName()
+ " appears to be already registered with the locatable input split assigner, ignoring vertex...");
return;
}
synchronized (splitStore) {
for (int i = 0; i < inputSplits.length; ++i) {
// TODO: Improve this
final InputSplit inputSplit = inputSplits[i];
if (!(inputSplit instanceof LocatableInputSplit)) {
LOG.error("Input split " + i + " of vertex " + groupVertex.getName() + " is of type "
+ inputSplit.getClass() + ", ignoring split...");
continue;
}
splitStore.addSplit((LocatableInputSplit) inputSplit);
}
}
}
@Override
public void unregisterGroupVertex(final ExecutionGroupVertex groupVertex) {
this.vertexMap.remove(groupVertex);
}
@Override
public InputSplit getNextInputSplit(final ExecutionVertex vertex) {
final ExecutionGroupVertex groupVertex = vertex.getGroupVertex();
final LocatableInputSplitList splitStore = this.vertexMap.get(groupVertex);
if (splitStore == null) {
return null;
}
final AbstractInstance instance = vertex.getAllocatedResource().getInstance();
if (instance == null) {
LOG.error("Instance is null, returning random split");
return null;
}
return splitStore.getNextInputSplit(instance);
}
}