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The Apache Cassandra Project develops a highly scalable second-generation distributed database, bringing together Dynamo's fully distributed design and Bigtable's ColumnFamily-based data model.
/*
* 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.cassandra.hints;
import java.io.File;
import java.io.IOException;
import java.nio.ByteBuffer;
import java.nio.channels.FileChannel;
import java.util.zip.CRC32;
import org.apache.cassandra.io.compress.ICompressor;
public class CompressedHintsWriter extends HintsWriter
{
// compressed and uncompressed size is stored at the beginning of each compressed block
static final int METADATA_SIZE = 8;
private final ICompressor compressor;
private volatile ByteBuffer compressionBuffer = null;
public CompressedHintsWriter(File directory, HintsDescriptor descriptor, File file, FileChannel channel, int fd, CRC32 globalCRC)
{
super(directory, descriptor, file, channel, fd, globalCRC);
compressor = descriptor.createCompressor();
assert compressor != null;
}
protected void writeBuffer(ByteBuffer bb) throws IOException
{
int originalSize = bb.remaining();
int estimatedSize = compressor.initialCompressedBufferLength(originalSize) + METADATA_SIZE;
if (compressionBuffer == null || compressionBuffer.capacity() < estimatedSize)
{
compressionBuffer = compressor.preferredBufferType().allocate(estimatedSize);
}
compressionBuffer.clear();
compressionBuffer.position(METADATA_SIZE);
compressor.compress(bb, compressionBuffer);
int compressedSize = compressionBuffer.position() - METADATA_SIZE;
compressionBuffer.rewind();
compressionBuffer.putInt(originalSize);
compressionBuffer.putInt(compressedSize);
compressionBuffer.rewind();
compressionBuffer.limit(compressedSize + METADATA_SIZE);
super.writeBuffer(compressionBuffer);
}
}