/*
 * Copyright 2009-2010 University of California, Irvine
 * 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 from
 * 
 *     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 edu.uci.ics.hyracks.dataflow.hadoop.mapreduce;

import java.io.ByteArrayInputStream;
import java.io.ByteArrayOutputStream;
import java.io.DataInputStream;
import java.io.DataOutputStream;
import java.io.IOException;
import java.io.Serializable;

import org.apache.hadoop.io.Writable;

public class MarshalledWritable<T extends Writable> implements Serializable {
    private static final long serialVersionUID = 1L;

    private byte[] bytes;

    public MarshalledWritable() {
    }

    public void set(T o) throws IOException {
        ByteArrayOutputStream baos = new ByteArrayOutputStream();
        DataOutputStream dos = new DataOutputStream(baos);
        dos.writeUTF(o.getClass().getName());
        o.write(dos);
        dos.close();
        bytes = baos.toByteArray();
    }

    public T get() throws Exception {
        ByteArrayInputStream bais = new ByteArrayInputStream(bytes);
        DataInputStream dis = new DataInputStream(bais);
        String className = dis.readUTF();
        T o = (T) HadoopTools.newInstance(className);
        o.readFields(dis);
        return o;
    }
}