com.koda.integ.hbase.util.CacheableSerializer.java Source code

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Here is the source code for com.koda.integ.hbase.util.CacheableSerializer.java

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/*******************************************************************************
* Copyright (c) 2013 Vladimir Rodionov. All Rights Reserved
*
* This code is released under the GNU Affero General Public License.
*
* See: http://www.fsf.org/licensing/licenses/agpl-3.0.html
*
* VLADIMIR RODIONOV MAKES NO REPRESENTATIONS OR WARRANTIES ABOUT THE SUITABILITY
* OF THE SOFTWARE, EITHER EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE
* IMPLIED WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE, OR
* NON-INFRINGEMENT. Vladimir Rodionov SHALL NOT BE LIABLE FOR ANY DAMAGES SUFFERED
* BY LICENSEE AS A RESULT OF USING, MODIFYING OR DISTRIBUTING THIS SOFTWARE OR
* ITS DERIVATIVES.
*
* Author: Vladimir Rodionov
*
*******************************************************************************/
package com.koda.integ.hbase.util;

import java.io.IOException;
import java.lang.reflect.Field;
import java.nio.ByteBuffer;
import java.util.Arrays;
import java.util.List;
import java.util.concurrent.atomic.AtomicReference;

import com.koda.integ.hbase.blockcache.OffHeapBlockCache;
import com.koda.integ.hbase.stub.ByteArrayCacheable;

import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.apache.hadoop.hbase.io.hfile.Cacheable;
import org.apache.hadoop.hbase.io.hfile.CacheableDeserializer;
import org.apache.hadoop.hbase.io.hfile.HFileBlock;

import com.koda.io.serde.Serializer;

// TODO: Auto-generated Javadoc
/**
 * The Class CacheableSerializer.
 */
public class CacheableSerializer implements Serializer<Cacheable> {
    /** The Constant LOG. */
    static final Log LOG = LogFactory.getLog(CacheableSerializer.class);
    /** The id. */
    private static int ID = START_ID - 4;

    /** The deserializer. */
    private static AtomicReference<CacheableDeserializer<Cacheable>> deserializer = new AtomicReference<CacheableDeserializer<Cacheable>>(
            null);

    /* (non-Javadoc)
     * @see com.koda.io.serde.Serializer#getClassID(java.lang.Class)
     */
    @Override
    public int getClassID(Class<?> clz) {
        return CacheableSerializer.ID;
    }

    /* (non-Javadoc)
     * @see com.koda.io.serde.Serializer#getClassNamesAsList()
     */
    @Override
    public List<String> getClassNamesAsList() {
        return Arrays.asList(new String[] { org.apache.hadoop.hbase.io.hfile.HFileBlock.class.getName(),
                ByteArrayCacheable.class.getName() });
    }

    /* (non-Javadoc)
     * @see com.koda.io.serde.Serializer#getClassesAsList()
     */
    @Override
    public List<Class<?>> getClassesAsList() {
        return Arrays.asList(
                new Class<?>[] { org.apache.hadoop.hbase.io.hfile.HFileBlock.class, ByteArrayCacheable.class });
    }

    /* (non-Javadoc)
     * @see com.koda.io.serde.Serializer#init()
     */
    @Override
    public void init() {
        // TODO Auto-generated method stub

    }

    /* (non-Javadoc)
     * @see com.koda.io.serde.Serializer#read(java.nio.ByteBuffer)
     */
    @Override
    public Cacheable read(ByteBuffer buf) throws IOException {
        if (deserializer == null || deserializer.get() == null) {
            return null;
        }
        ByteBuffer bbuf = buf.slice();
        bbuf.order(buf.order());
        return deserializer.get().deserialize(bbuf);
    }

    /* (non-Javadoc)
     * @see com.koda.io.serde.Serializer#read(java.nio.ByteBuffer, java.lang.Object)
     */
    @Override
    public Cacheable read(ByteBuffer buf, Cacheable value) throws IOException {
        return read(buf);
    }

    /* (non-Javadoc)
     * @see com.koda.io.serde.Serializer#write(java.nio.ByteBuffer, java.lang.Object)
     */
    @Override
    public void write(ByteBuffer buf, Cacheable obj) throws IOException {
        if (deserializer.get() == null) {
            CacheableDeserializer<Cacheable> des = obj.getDeserializer();
            deserializer.compareAndSet(null, des);
        }
        // Serializer does not honor current buffer position
        int len = obj.getSerializedLength();
        int pos = buf.position();
        obj.serialize(buf);
        buf.limit(len + pos);
        buf.position(len + pos);
    }

    public static CacheableDeserializer<Cacheable> getDeserializer() {
        return deserializer.get();
    }

    public static void setSerializer(CacheableDeserializer<Cacheable> ser) {
        deserializer.set(ser);
    }

    @SuppressWarnings("unchecked")
    public static void setHFileDeserializer() {
        Field field = getProtectedField(HFileBlock.class, "blockDeserializer");

        if (field == null) {
            LOG.error("Could not get access to HFileBlock.blockDeserializer");
            return;
        }

        try {
            CacheableDeserializer<Cacheable> serde = (CacheableDeserializer<Cacheable>) field.get(null);
            if (serde != null) {
                deserializer.set(serde);
            } else {
                LOG.warn("HFileBlock.blockDeserializer is null");
            }
        } catch (Exception e) {
            LOG.warn("unable to read HFileBlock.blockDeserializer");
        }

    }

    @SuppressWarnings("unchecked")
    private static Field getProtectedField(Class klass, String fieldName) {
        Field field;

        try {
            field = klass.getDeclaredField(fieldName);
            field.setAccessible(true);
        } catch (Exception e) {
            throw new AssertionError(e);
        }

        return field;
    }

}