/**
* Licensed to the Apache Software Foundation (ASF) under one
* or more contributor license agreements. See the NOTICE file
* distributed with this work for additional information
* regarding copyright ownership. The ASF licenses this file
* to you 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 org.apache.crunch.types.writable;
import java.io.ByteArrayInputStream;
import java.io.ByteArrayOutputStream;
import java.io.DataInput;
import java.io.DataInputStream;
import java.io.DataOutputStream;
import org.apache.crunch.impl.mr.run.CrunchRuntimeException;
import org.apache.crunch.types.DeepCopier;
import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.io.Writable;
/**
* Performs deep copies of Writable values.
*
* @param <T> The type of Writable that can be copied
*/
public class WritableDeepCopier<T extends Writable> implements DeepCopier<T> {
private Class<T> writableClass;
public WritableDeepCopier(Class<T> writableClass) {
this.writableClass = writableClass;
}
@Override
public void initialize(Configuration conf) {
}
@Override
public T deepCopy(T source) {
ByteArrayOutputStream byteOutStream = new ByteArrayOutputStream();
DataOutputStream dataOut = new DataOutputStream(byteOutStream);
T copiedValue = null;
try {
source.write(dataOut);
dataOut.flush();
ByteArrayInputStream byteInStream = new ByteArrayInputStream(byteOutStream.toByteArray());
DataInput dataInput = new DataInputStream(byteInStream);
copiedValue = writableClass.newInstance();
copiedValue.readFields(dataInput);
} catch (Exception e) {
throw new CrunchRuntimeException("Error while deep copying " + source, e);
}
return copiedValue;
}
}