com.datasalt.utils.io.Serialization.java Source code

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Here is the source code for com.datasalt.utils.io.Serialization.java

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/**
 * Copyright [2011] [Datasalt Systems S.L.]
 *
 * 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.datasalt.utils.io;

import java.io.ByteArrayOutputStream;
import java.io.IOException;

import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.io.BytesWritable;
import org.apache.hadoop.io.DataInputBuffer;
import org.apache.hadoop.io.serializer.Deserializer;
import org.apache.hadoop.io.serializer.SerializationFactory;
import org.apache.hadoop.io.serializer.Serializer;

/**
 * You can use this utility class to serialize / deserialize anything in the Hadoop context.
 * It is thread safe. Instanciate once, reuse many times. Otherwhise it is not
 * efficient.
 * 
 * @author pere,epalace
 *
 */
@SuppressWarnings({ "rawtypes", "unchecked" })
public class Serialization {

    private SerializationFactory serialization;

    public Serialization(Configuration conf) throws IOException {
        serialization = new SerializationFactory(conf);
    }

    // only one byte array per thread, to make it thread safe and efficient
    ThreadLocal<ByteArrayOutputStream> cachedOutputStream = new ThreadLocal<ByteArrayOutputStream>() {

        @Override
        protected ByteArrayOutputStream initialValue() {
            return new ByteArrayOutputStream();
        }
    };

    ThreadLocal<DataInputBuffer> cachedInputStream = new ThreadLocal<DataInputBuffer>() {

        @Override
        protected DataInputBuffer initialValue() {
            return new DataInputBuffer();
        }
    };

    public byte[] ser(Object datum) throws IOException {
        Serializer ser = serialization.getSerializer(datum.getClass());
        ByteArrayOutputStream baOs = cachedOutputStream.get();
        baOs.reset();
        ser.open(baOs);
        ser.serialize(datum);
        ser.close();
        return baOs.toByteArray();

    }

    public <T> T deser(Object obj, BytesWritable writable) throws IOException {
        return (T) deser(obj, writable.getBytes(), 0, writable.getLength());
    }

    public <T> T deser(Object obj, byte[] datum, int offset, int length) throws IOException {
        Deserializer deSer = serialization.getDeserializer(obj.getClass());
        DataInputBuffer baIs = cachedInputStream.get();
        baIs.reset(datum, length);
        deSer.open(baIs);
        obj = deSer.deserialize(obj);
        deSer.close();
        baIs.close();
        return (T) obj;
    }
}