/***********************************************************************************************************************
* 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.pact.runtime.iterative.event;
import java.io.ByteArrayInputStream;
import java.io.ByteArrayOutputStream;
import java.io.DataInput;
import java.io.DataInputStream;
import java.io.DataOutput;
import java.io.DataOutputStream;
import java.io.IOException;
import java.util.Map;
import eu.stratosphere.api.common.aggregators.Aggregator;
import eu.stratosphere.nephele.event.task.AbstractTaskEvent;
import eu.stratosphere.types.Value;
import eu.stratosphere.util.InstantiationUtil;
public abstract class IterationEventWithAggregators extends AbstractTaskEvent {
protected static final String[] NO_STRINGS = new String[0];
protected static final Value[] NO_VALUES = new Value[0];
private String[] aggNames;
private String[] classNames;
private byte[][] serializedData;
private Value[] aggregates;
protected IterationEventWithAggregators() {
this.aggNames = NO_STRINGS;
this.aggregates = NO_VALUES;
}
protected IterationEventWithAggregators(String aggregatorName, Value aggregate) {
if (aggregatorName == null || aggregate == null) {
throw new NullPointerException();
}
this.aggNames = new String[] { aggregatorName };
this.aggregates = new Value[] { aggregate };
}
protected IterationEventWithAggregators(Map<String, Aggregator<?>> aggregators) {
int num = aggregators.size();
if (num == 0) {
this.aggNames = NO_STRINGS;
this.aggregates = NO_VALUES;
} else {
this.aggNames = new String[num];
this.aggregates = new Value[num];
int i = 0;
for (Map.Entry<String, Aggregator<?>> entry : aggregators.entrySet()) {
this.aggNames[i] = entry.getKey();
this.aggregates[i] = entry.getValue().getAggregate();
i++;
}
}
}
public String[] getAggregatorNames() {
return this.aggNames;
}
public Value[] getAggregates(ClassLoader classResolver) {
if (aggregates == null) {
// we have read the binary data, but not yet turned into the objects
final int num = aggNames.length;
aggregates = new Value[num];
for (int i = 0; i < num; i++) {
Value v;
try {
Class<? extends Value> valClass = Class.forName(classNames[i], true, classResolver).asSubclass(Value.class);
v = InstantiationUtil.instantiate(valClass, Value.class);
}
catch (ClassNotFoundException e) {
throw new RuntimeException("Could not load user-defined class '" + classNames[i] + "'.", e);
}
catch (ClassCastException e) {
throw new RuntimeException("User-defined aggregator class is not a value sublass.");
}
DataInputStream in = new DataInputStream(new ByteArrayInputStream(serializedData[i]));
try {
v.read(in);
in.close();
} catch (IOException e) {
throw new RuntimeException("Error while deserializing the user-defined aggregate class.", e);
}
aggregates[i] = v;
}
}
return this.aggregates;
}
@Override
public void write(DataOutput out) throws IOException {
int num = this.aggNames.length;
out.writeInt(num);
ByteArrayOutputStream boas = new ByteArrayOutputStream();
DataOutputStream bufferStream = new DataOutputStream(boas);
for (int i = 0; i < num; i++) {
// aggregator name and type
out.writeUTF(this.aggNames[i]);
out.writeUTF(this.aggregates[i].getClass().getName());
// aggregator value indirect as a byte array
this.aggregates[i].write(bufferStream);
bufferStream.flush();
byte[] bytes = boas.toByteArray();
out.writeInt(bytes.length);
out.write(bytes);
boas.reset();
}
bufferStream.close();
boas.close();
}
@Override
public void read(DataInput in) throws IOException {
int num = in.readInt();
if (num == 0) {
this.aggNames = NO_STRINGS;
this.aggregates = NO_VALUES;
} else {
if (this.aggNames == null || num > this.aggNames.length) {
this.aggNames = new String[num];
}
if (this.classNames == null || num > this.classNames.length) {
this.classNames = new String[num];
}
if (this.serializedData == null || num > this.serializedData.length) {
this.serializedData = new byte[num][];
}
for (int i = 0; i < num; i++) {
this.aggNames[i] = in.readUTF();
this.classNames[i] = in.readUTF();
int len = in.readInt();
byte[] data = new byte[len];
this.serializedData[i] = data;
in.readFully(data);
}
this.aggregates = null;
}
}
}