/*
* 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;
import com.hazelcast.map.impl.MapService;
import com.hazelcast.map.impl.RecordStore;
import com.hazelcast.mapreduce.KeyValueSource;
import com.hazelcast.mapreduce.PartitionIdAware;
import com.hazelcast.nio.Address;
import com.hazelcast.nio.ObjectDataInput;
import com.hazelcast.nio.ObjectDataOutput;
import com.hazelcast.nio.serialization.Data;
import com.hazelcast.nio.serialization.IdentifiedDataSerializable;
import com.hazelcast.nio.serialization.SerializationService;
import com.hazelcast.partition.InternalPartitionService;
import com.hazelcast.spi.NodeEngine;
import com.hazelcast.spi.impl.NodeEngineImpl;
import java.io.IOException;
import java.util.Iterator;
import java.util.Map;
/**
* This {@link com.hazelcast.mapreduce.KeyValueSource} implementation is used in
* {@link com.hazelcast.mapreduce.KeyValueSource#fromMap(com.hazelcast.core.IMap)} to generate a default
* implementation based on a Hazelcast {@link com.hazelcast.core.IMap}.
*
* @param <K> type of the key of the IMap
* @param <V> type of the value of the IMap
*/
public class MapKeyValueSource<K, V>
extends KeyValueSource<K, V>
implements IdentifiedDataSerializable, PartitionIdAware {
// This prevents excessive creation of map entries for a serialized operation
private final MapReduceSimpleEntry<K, V> simpleEntry = new MapReduceSimpleEntry<K, V>();
private String mapName;
private transient int partitionId;
private transient SerializationService ss;
private transient Iterator<Map.Entry<Data, Data>> iterator;
private transient Map.Entry<Data, Data> nextElement;
MapKeyValueSource() {
}
public MapKeyValueSource(String mapName) {
this.mapName = mapName;
}
@Override
public boolean open(NodeEngine nodeEngine) {
NodeEngineImpl nei = (NodeEngineImpl) nodeEngine;
InternalPartitionService ps = nei.getPartitionService();
MapService mapService = nei.getService(MapService.SERVICE_NAME);
ss = nei.getSerializationService();
Address partitionOwner = ps.getPartitionOwner(partitionId);
if (partitionOwner == null) {
return false;
}
RecordStore recordStore = mapService.getMapServiceContext().getRecordStore(partitionId, mapName);
iterator = recordStore.entrySetData().iterator();
return true;
}
@Override
public void close()
throws IOException {
}
@Override
public boolean hasNext() {
boolean hasNext = iterator.hasNext();
nextElement = hasNext ? iterator.next() : null;
return hasNext;
}
@Override
public K key() {
if (nextElement == null) {
throw new IllegalStateException("no more elements");
}
Data keyData = nextElement.getKey();
K key = (K) ss.toObject(keyData);
simpleEntry.setKeyData(keyData);
simpleEntry.setKey(key);
return key;
}
@Override
public Map.Entry<K, V> element() {
if (nextElement == null) {
throw new IllegalStateException("no more elements");
}
if (!nextElement.getKey().equals(simpleEntry.getKeyData())) {
simpleEntry.setKey((K) ss.toObject(nextElement.getKey()));
}
simpleEntry.setValue((V) ss.toObject(nextElement.getValue()));
return simpleEntry;
}
@Override
public boolean reset() {
iterator = null;
nextElement = null;
return true;
}
@Override
public void setPartitionId(int partitionId) {
this.partitionId = partitionId;
}
@Override
public void writeData(ObjectDataOutput out)
throws IOException {
out.writeUTF(mapName);
}
@Override
public void readData(ObjectDataInput in)
throws IOException {
mapName = in.readUTF();
}
@Override
public int getFactoryId() {
return MapReduceDataSerializerHook.F_ID;
}
@Override
public int getId() {
return MapReduceDataSerializerHook.KEY_VALUE_SOURCE_MAP;
}
}