/***********************************************************************************************************************
* 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.util;
import java.io.DataInput;
import java.io.DataOutput;
import java.io.IOException;
import java.util.ArrayList;
import java.util.Iterator;
import eu.stratosphere.core.io.IOReadableWritable;
import eu.stratosphere.core.io.StringRecord;
import eu.stratosphere.util.StringUtils;
/**
* This class extends a standard {@link java.util.ArrayList} by implementing the
* {@link eu.stratosphere.core.io.IOReadableWritable} interface. As a result, array lists of this type can be used
* with Nephele's RPC system.
* <p>
* This class is not thread-safe.
*
* @param <E>
* the type of object stored inside this array list
*/
public class SerializableArrayList<E extends IOReadableWritable> extends ArrayList<E> implements IOReadableWritable {
/**
* Generated serial version UID.
*/
private static final long serialVersionUID = 8196856588290198537L;
/**
* Constructs an empty list with an initial capacity of ten.
*/
public SerializableArrayList() {
super();
}
/**
* Constructs an empty list with the specified initial capacity.
*
* @param initialCapacity
* the initial capacity of the list
*/
public SerializableArrayList(final int initialCapacity) {
super(initialCapacity);
}
@Override
public void write(final DataOutput out) throws IOException {
out.writeInt(size());
final Iterator<E> it = iterator();
while (it.hasNext()) {
final E element = it.next();
// Write out type
StringRecord.writeString(out, element.getClass().getName());
// Write out element itself
element.write(out);
}
}
@SuppressWarnings("unchecked")
@Override
public void read(final DataInput in) throws IOException {
// Make sure the list is empty
clear();
final int numberOfElements = in.readInt();
for (int i = 0; i < numberOfElements; i++) {
final String elementType = StringRecord.readString(in);
Class<E> clazz = null;
try {
clazz = (Class<E>) Class.forName(elementType);
} catch (ClassNotFoundException e) {
throw new IOException(StringUtils.stringifyException(e));
}
E element = null;
try {
element = clazz.newInstance();
} catch (Exception e) {
throw new IOException(StringUtils.stringifyException(e));
}
element.read(in);
add(element);
}
}
@Override
public boolean equals(final Object obj) {
if (!(obj instanceof SerializableArrayList<?>)) {
return false;
}
final SerializableArrayList<?> sal = (SerializableArrayList<?>) obj;
if (this.size() != sal.size()) {
return false;
}
final Iterator<E> it = iterator();
final Iterator<?> it2 = sal.iterator();
while (it.hasNext()) {
final E e = it.next();
final Object obj2 = it2.next();
if (!e.equals(obj2)) {
return false;
}
}
return true;
}
@Override
public int hashCode() {
int hashCode = Integer.MIN_VALUE;
if (!isEmpty()) {
final E e = get(0);
hashCode += Math.abs(e.getClass().hashCode());
}
hashCode += size();
return hashCode;
}
}