/*
* (C) 2007-2012 Alibaba Group Holding Limited.
*
* 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.
* Authors:
* wuhua <wq163@163.com> , boyan <killme2008@gmail.com>
*/
package com.taobao.metamorphosis.server.transaction;
import java.io.Closeable;
import java.io.File;
import java.io.IOException;
import java.io.RandomAccessFile;
import java.nio.ByteBuffer;
import java.nio.channels.FileChannel;
import com.taobao.metamorphosis.server.utils.FileUtils;
import com.taobao.metamorphosis.utils.codec.impl.JavaDeserializer;
import com.taobao.metamorphosis.utils.codec.impl.JavaSerializer;
/**
* �ֹ������������־
*
* @author boyan(boyan@taobao.com)
* @date 2011-11-24
*
*/
public class HeuristicTransactionJournal implements Closeable {
private final FileChannel fc;
private final JavaSerializer serializer;
private final JavaDeserializer deserializer;
private static final String FILE_NAME = "heuristic.log";
public HeuristicTransactionJournal(final String path) throws IOException {
FileUtils.makesureDir(new File(path));
this.serializer = new JavaSerializer();
this.deserializer = new JavaDeserializer();
final File transactionsDir = new File(path + File.separator + "transactions");
FileUtils.makesureDir(transactionsDir);
this.fc = new RandomAccessFile(new File(transactionsDir + File.separator + FILE_NAME), "rw").getChannel();
}
@Override
public synchronized void close() throws IOException {
this.fc.force(true);
this.fc.close();
}
public void write(final Object obj) throws Exception {
if (!this.fc.isOpen()) {
return;
}
if (obj == null) {
return;
}
final byte[] result = this.serializer.encodeObject(obj);
final ByteBuffer buf = ByteBuffer.wrap(result);
synchronized (this) {
while (buf.hasRemaining()) {
this.fc.write(buf, 0);
}
this.fc.truncate(result.length);
}
}
public Object read() throws Exception {
byte[] data = null;
synchronized (this) {
final long size = this.fc.size();
if (size == 0) {
return null;
}
final ByteBuffer buf = ByteBuffer.allocate((int) size);
this.fc.position(0);
while (buf.hasRemaining()) {
this.fc.read(buf);
}
buf.flip();
data = new byte[buf.remaining()];
buf.get(data);
}
if (data != null) {
return this.deserializer.decodeObject(data);
}
else {
return null;
}
}
}