/*
* 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.collection.CollectionItem;
import com.hazelcast.collection.set.SetContainer;
import com.hazelcast.collection.set.SetService;
import com.hazelcast.mapreduce.KeyValueSource;
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.partition.strategy.StringAndPartitionAwarePartitioningStrategy;
import com.hazelcast.spi.NodeEngine;
import com.hazelcast.spi.impl.NodeEngineImpl;
import java.io.IOException;
import java.util.ArrayList;
import java.util.Iterator;
import java.util.List;
import java.util.Map;
/**
* This {@link com.hazelcast.mapreduce.KeyValueSource} implementation is used in
* {@link com.hazelcast.mapreduce.KeyValueSource#fromSet(com.hazelcast.core.ISet)} to generate a default
* implementation based on a Hazelcast {@link com.hazelcast.core.ISet}.
*
* @param <V> type of the values inside the ISet
*/
public class SetKeyValueSource<V>
extends KeyValueSource<String, V>
implements IdentifiedDataSerializable {
// This prevents excessive creation of map entries for a serialized operation
private final MapReduceSimpleEntry<String, V> simpleEntry = new MapReduceSimpleEntry<String, V>();
private String setName;
private transient SerializationService ss;
private transient Iterator<CollectionItem> iterator;
private transient CollectionItem nextElement;
public SetKeyValueSource() {
}
public SetKeyValueSource(String setName) {
this.setName = setName;
}
@Override
public boolean open(NodeEngine nodeEngine) {
NodeEngineImpl nei = (NodeEngineImpl) nodeEngine;
ss = nei.getSerializationService();
Address thisAddress = nei.getThisAddress();
InternalPartitionService ps = nei.getPartitionService();
Data data = ss.toData(setName, StringAndPartitionAwarePartitioningStrategy.INSTANCE);
int partitionId = ps.getPartitionId(data);
Address partitionOwner = ps.getPartitionOwner(partitionId);
if (partitionOwner == null) {
return false;
}
if (thisAddress.equals(partitionOwner)) {
SetService setService = nei.getService(SetService.SERVICE_NAME);
SetContainer setContainer = setService.getOrCreateContainer(setName, false);
List<CollectionItem> items = new ArrayList<CollectionItem>(setContainer.getCollection());
iterator = items.iterator();
}
return true;
}
@Override
public boolean hasNext() {
boolean hasNext = iterator == null ? false : iterator.hasNext();
nextElement = hasNext ? iterator.next() : null;
return hasNext;
}
@Override
public String key() {
return setName;
}
@Override
public Map.Entry<String, V> element() {
Object value = nextElement.getValue();
if (value != null) {
value = ss.toObject(value);
}
simpleEntry.setKey(setName);
simpleEntry.setValue((V) value);
return simpleEntry;
}
@Override
public boolean reset() {
iterator = null;
nextElement = null;
return true;
}
@Override
public void close()
throws IOException {
iterator = null;
nextElement = null;
}
@Override
public void writeData(ObjectDataOutput out)
throws IOException {
out.writeUTF(setName);
}
@Override
public void readData(ObjectDataInput in)
throws IOException {
setName = in.readUTF();
}
@Override
public int getFactoryId() {
return MapReduceDataSerializerHook.F_ID;
}
@Override
public int getId() {
return MapReduceDataSerializerHook.KEY_VALUE_SOURCE_SET;
}
}