/*
* Copyright (c) 2008-2013, Hazelcast, Inc. All Rights Reserved.
*
* 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 com.hazelcast.mapreduce.impl.operation;
import com.hazelcast.mapreduce.TopologyChangedException;
import com.hazelcast.mapreduce.TopologyChangedStrategy;
import com.hazelcast.mapreduce.impl.MapReduceDataSerializerHook;
import com.hazelcast.mapreduce.impl.MapReduceService;
import com.hazelcast.mapreduce.impl.task.JobSupervisor;
import com.hazelcast.nio.Address;
import com.hazelcast.nio.ObjectDataInput;
import com.hazelcast.nio.ObjectDataOutput;
import java.io.IOException;
import java.util.HashMap;
import java.util.HashSet;
import java.util.Map;
import java.util.Set;
import static com.hazelcast.mapreduce.TopologyChangedStrategy.CANCEL_RUNNING_OPERATION;
import static com.hazelcast.mapreduce.impl.operation.RequestPartitionResult.ResultState.CHECK_STATE_FAILED;
import static com.hazelcast.mapreduce.impl.operation.RequestPartitionResult.ResultState.NO_SUPERVISOR;
import static com.hazelcast.mapreduce.impl.operation.RequestPartitionResult.ResultState.SUCCESSFUL;
/**
* This operation is used to request assignment for keys on the job owners node. The job owner
* is the only node capable of assigning those reducing nodes to be aware of the number of reducers
* per partition and also aware of possible topology changes while executing the job.
*/
public class KeysAssignmentOperation
extends ProcessingOperation {
private Set<Object> keys;
private KeysAssignmentResult result;
public KeysAssignmentOperation() {
}
public KeysAssignmentOperation(String name, String jobId, Set<Object> keys) {
super(name, jobId);
this.keys = keys;
}
@Override
public Object getResponse() {
return result;
}
@Override
public void run()
throws Exception {
MapReduceService mapReduceService = getService();
JobSupervisor supervisor = mapReduceService.getJobSupervisor(getName(), getJobId());
if (supervisor == null) {
this.result = new KeysAssignmentResult(NO_SUPERVISOR, null);
return;
}
Map<Object, Address> assignment = new HashMap<Object, Address>();
// Precheck if still all members are available
if (!supervisor.checkAssignedMembersAvailable()) {
TopologyChangedStrategy tcs = supervisor.getConfiguration().getTopologyChangedStrategy();
if (tcs == CANCEL_RUNNING_OPERATION) {
Exception exception = new TopologyChangedException();
supervisor.cancelAndNotify(exception);
this.result = new KeysAssignmentResult(CHECK_STATE_FAILED, assignment);
return;
// TODO Not yet fully supported
/* } else if (tcs == DISCARD_AND_RESTART) {
* supervisor.cancelNotifyAndRestart();
*/
} else {
Exception exception = new TopologyChangedException("Unknown or unsupported TopologyChangedStrategy");
supervisor.cancelAndNotify(exception);
this.result = new KeysAssignmentResult(CHECK_STATE_FAILED, assignment);
return;
}
}
for (Object key : keys) {
Address address = supervisor.assignKeyReducerAddress(key);
assignment.put(key, address);
}
this.result = new KeysAssignmentResult(SUCCESSFUL, assignment);
}
@Override
protected void writeInternal(ObjectDataOutput out)
throws IOException {
super.writeInternal(out);
out.writeInt(keys.size());
for (Object key : keys) {
out.writeObject(key);
}
}
@Override
protected void readInternal(ObjectDataInput in)
throws IOException {
super.readInternal(in);
int size = in.readInt();
keys = new HashSet<Object>();
for (int i = 0; i < size; i++) {
keys.add(in.readObject());
}
}
@Override
public int getFactoryId() {
return MapReduceDataSerializerHook.F_ID;
}
@Override
public int getId() {
return MapReduceDataSerializerHook.KEYS_ASSIGNMENT_OPERATION;
}
}