/*
* Copyright 2011 sunli [sunli1223@gmail.com][weibo.com@sunli1223]
*
* 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.google.code.fqueue.log;
import java.io.File;
import java.io.IOException;
import java.io.RandomAccessFile;
import java.lang.reflect.Method;
import java.nio.MappedByteBuffer;
import java.nio.channels.FileChannel;
import java.nio.channels.FileChannel.MapMode;
import java.security.AccessController;
import java.security.PrivilegedAction;
import java.util.concurrent.Executor;
import java.util.concurrent.Executors;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import com.google.code.fqueue.exception.FileEOFException;
import com.google.code.fqueue.exception.FileFormatException;
/**
*@author sunli
*@date 2011-5-18
*@version $Id: LogEntity.java 2 2011-07-31 12:25:36Z sunli1223@gmail.com $
*/
public class LogEntity {
private final Logger log = LoggerFactory.getLogger(LogEntity.class);
public static final byte WRITESUCCESS = 1;
public static final byte WRITEFAILURE = 2;
public static final byte WRITEFULL = 3;
public static final String MAGIC = "FQueuefs";
public static int messageStartPosition = 20;
private final Executor executor = Executors.newSingleThreadExecutor();
private File file;
private RandomAccessFile raFile;
private FileChannel fc;
public MappedByteBuffer mappedByteBuffer;
private int fileLimitLength = 1024 * 1024 * 40;
private LogIndex db = null;
/**
* 文件操作位置信息
*/
private String magicString = null;
private int version = -1;
private int readerPosition = -1;
private int writerPosition = -1;
private int nextFile = -1;
private int endPosition = -1;
private int currentFileNumber = -1;
public LogEntity(String path, LogIndex db, int fileNumber,
int fileLimitLength) throws IOException, FileFormatException {
this.currentFileNumber = fileNumber;
this.fileLimitLength = fileLimitLength;
this.db = db;
file = new File(path);
// 文件不存在，创建文件
if (file.exists() == false) {
createLogEntity();
FileRunner.addCreateFile(Integer.toString(fileNumber + 1));
} else {
raFile = new RandomAccessFile(file, "rwd");
if (raFile.length() < LogEntity.messageStartPosition) {
throw new FileFormatException("file format error");
}
fc = raFile.getChannel();
mappedByteBuffer = fc.map(MapMode.READ_WRITE, 0,
this.fileLimitLength);
// magicString
byte[] b = new byte[8];
mappedByteBuffer.get(b);
magicString = new String(b);
if (magicString.equals(MAGIC) == false) {
throw new FileFormatException("file format error");
}
// version
version = mappedByteBuffer.getInt();
// nextfile
nextFile = mappedByteBuffer.getInt();
endPosition = mappedByteBuffer.getInt();
// 未写满
if (endPosition == -1) {
this.writerPosition = db.getWriterPosition();
} else if (endPosition == -2) {// 预分配的文件
this.writerPosition = LogEntity.messageStartPosition;
db.putWriterPosition(this.writerPosition);
mappedByteBuffer.position(16);
mappedByteBuffer.putInt(-1);
this.endPosition = -1;
} else {
this.writerPosition = endPosition;
}
if (db.getReaderIndex() == this.currentFileNumber) {
this.readerPosition = db.getReaderPosition();
} else {
this.readerPosition = LogEntity.messageStartPosition;
}
}
executor.execute(new Sync());
}
public class Sync implements Runnable {
@Override
public void run() {
while (true) {
if (mappedByteBuffer != null) {
try {
mappedByteBuffer.force();
} catch (Exception e) {
break;
}
try {
Thread.sleep(10);
} catch (InterruptedException e) {
break;
}
} else {
break;
}
}
}
}
public int getCurrentFileNumber() {
return this.currentFileNumber;
}
public int getNextFile() {
return this.nextFile;
}
private boolean createLogEntity() throws IOException {
if (file.createNewFile() == false) {
return false;
}
raFile = new RandomAccessFile(file, "rwd");
fc = raFile.getChannel();
mappedByteBuffer = fc.map(MapMode.READ_WRITE, 0, this.fileLimitLength);
mappedByteBuffer.put(MAGIC.getBytes());
mappedByteBuffer.putInt(version);// 8 version
mappedByteBuffer.putInt(nextFile);// 12next fileindex
mappedByteBuffer.putInt(endPosition);// 16
mappedByteBuffer.force();
this.magicString = MAGIC;
this.writerPosition = LogEntity.messageStartPosition;
this.readerPosition = LogEntity.messageStartPosition;
db.putWriterPosition(this.writerPosition);
return true;
}
/**
* 记录写位置
*
* @param pos
*/
private void putWriterPosition(int pos) {
db.putWriterPosition(pos);
}
private void putReaderPosition(int pos) {
db.putReaderPosition(pos);
}
/**
* write next File number id.
*
* @param number
*/
public void putNextFile(int number) {
mappedByteBuffer.position(12);
mappedByteBuffer.putInt(number);
this.nextFile = number;
}
public boolean isFull(int increment) {
// confirm if the file is full
if (this.fileLimitLength < this.writerPosition + increment) {
return true;
}
return false;
}
public byte write(byte[] log) {
int increment = log.length + 4;
if (isFull(increment)) {
mappedByteBuffer.position(16);
mappedByteBuffer.putInt(this.writerPosition);
this.endPosition = this.writerPosition;
return WRITEFULL;
}
mappedByteBuffer.position(this.writerPosition);
mappedByteBuffer.putInt(log.length);
mappedByteBuffer.put(log);
this.writerPosition += increment;
putWriterPosition(this.writerPosition);
return WRITESUCCESS;
}
public byte[] readNextAndRemove() throws FileEOFException {
if (this.endPosition != -1 && this.readerPosition >= this.endPosition) {
throw new FileEOFException("file eof");
}
// readerPosition must be less than writerPosition
if (this.readerPosition >= this.writerPosition) {
return null;
}
mappedByteBuffer.position(this.readerPosition);
int length = mappedByteBuffer.getInt();
byte[] b = new byte[length];
this.readerPosition += length + 4;
mappedByteBuffer.get(b);
putReaderPosition(this.readerPosition);
return b;
}
public void close() {
try {
if(mappedByteBuffer==null){
return;
}
mappedByteBuffer.force();
AccessController.doPrivileged(new PrivilegedAction<Object>() {
public Object run() {
try {
Method getCleanerMethod = mappedByteBuffer.getClass()
.getMethod("cleaner", new Class[0]);
getCleanerMethod.setAccessible(true);
sun.misc.Cleaner cleaner = (sun.misc.Cleaner) getCleanerMethod
.invoke(mappedByteBuffer, new Object[0]);
cleaner.clean();
} catch (Exception e) {
e.printStackTrace();
}
return null;
}
});
mappedByteBuffer = null;
fc.close();
raFile.close();
} catch (IOException e) {
log.error("close logentity file error:", e);
}
}
public String headerInfo() {
StringBuilder sb = new StringBuilder();
sb.append(" magicString:");
sb.append(magicString);
sb.append(" version:");
sb.append(version);
sb.append(" readerPosition:");
sb.append(readerPosition);
sb.append(" writerPosition:");
sb.append(writerPosition);
sb.append(" nextFile:");
sb.append(nextFile);
sb.append(" endPosition:");
sb.append(endPosition);
sb.append(" currentFileNumber:");
sb.append(currentFileNumber);
return sb.toString();
}
}