fr.dyade.aaa.util.AbstractTransaction Maven / Gradle / Ivy
/*
* Copyright (C) 2009 - 2012 ScalAgent Distributed Technologies
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2.1 of the License, or any later version.
*
* This library is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this library; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307
* USA.
*/
package fr.dyade.aaa.util;
import java.io.ByteArrayInputStream;
import java.io.ByteArrayOutputStream;
import java.io.DataOutputStream;
import java.io.File;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.ObjectInputStream;
import java.io.ObjectOutputStream;
import java.io.ObjectStreamConstants;
import java.io.Serializable;
import java.nio.ByteBuffer;
import java.util.Hashtable;
import org.objectweb.util.monolog.api.BasicLevel;
import fr.dyade.aaa.common.encoding.ByteBufferDecoder;
import fr.dyade.aaa.common.encoding.ByteBufferEncoder;
import fr.dyade.aaa.common.encoding.Encodable;
import fr.dyade.aaa.common.encoding.EncodableFactory;
import fr.dyade.aaa.common.encoding.EncodableFactoryRepository;
import fr.dyade.aaa.common.encoding.SerializableWrapper;
/**
* The AbstractTransaction class implements the common part of the Transaction
* Transaction interface. A transaction implementation only needs to define several
* methods: saveInLog, loadByteArray, delete and commit.
*
* @see Transaction
*/
public abstract class AbstractTransaction extends BaseTransaction {
private static final byte JAVA_SERIALIZATION_TAG = 0x0;
private static final byte ENCODING_TAG = 0x1;
private boolean onlyUseJavaSerialization;
protected long startTime = 0L;
/**
* Returns the starting time.
*
* @return The starting time.
*/
public long getStartTime() {
return startTime;
}
public AbstractTransaction() {}
// State of the transaction monitor.
protected int phase;
/**
* Returns the transaction state.
* @return the transaction state.
*
* @see fr.dyade.aaa.util.Transaction#getPhase()
*/
public final int getPhase() {
return phase;
}
/**
* Returns a string representation of the transaction state.
* @return the string representation of the transaction state.
*
* @see fr.dyade.aaa.util.Transaction#getPhaseInfo()
*/
public final String getPhaseInfo() {
return PhaseInfo[phase];
}
/**
* Changes the transaction state.
*
* @param newPhase the new transaction state.
* @throws IOException
*/
protected abstract void setPhase(int newPhase) throws IOException;
protected File dir = null;
/**
* ThreadLocal variable used to get the log to associate state with each
* thread. The log contains all operations do by the current thread since
* the last commit. On commit, its content is added to current
* log (clog, memory + disk), then it is freed.
*/
protected ThreadLocal perThreadContext = null;
public abstract void initRepository() throws IOException;
public final void init(String path) throws IOException {
phase = INIT;
if (logmon.isLoggable(BasicLevel.INFO))
logmon.log(BasicLevel.INFO, "Transaction, init():");
dir = new File(path);
if (!dir.exists()) dir.mkdirs();
if (!dir.isDirectory())
throw new FileNotFoundException(path + " is not a directory.");
// Saves the transaction classname in order to prevent use of a
// different one after restart (see AgentServer.init).
DataOutputStream ldos = null;
try {
File tfc = new File(dir, "TFC");
if (! tfc.exists()) {
ldos = new DataOutputStream(new FileOutputStream(tfc));
ldos.writeUTF(getClass().getName());
ldos.flush();
}
} finally {
if (ldos != null) ldos.close();
}
loadProperties(dir);
onlyUseJavaSerialization = getBoolean("Transaction.OnlyUseJavaSerialization");
initRepository();
saveProperties(dir);
perThreadContext = new ThreadLocal() {
protected synchronized Context initialValue() {
return new Context();
}
};
startTime = System.currentTimeMillis();
if (logmon.isLoggable(BasicLevel.INFO))
logmon.log(BasicLevel.INFO, "Transaction, initialized " + startTime);
/* The Transaction subsystem is ready */
setPhase(FREE);
}
/**
* Start a transaction validation, the validation phase needs 3 phases: begin, commit
* and release. The begin ensure the mutual exclusion of the current transaction.
*
* @see fr.dyade.aaa.util.Transaction#begin()
*/
public final synchronized void begin() throws IOException {
while (phase != FREE) {
try {
wait();
} catch (InterruptedException exc) {
}
}
// Change the transaction state.
setPhase(RUN);
}
public class Context {
private Hashtable log = null;
private ByteArrayOutputStream bos = null;
private ObjectOutputStream oos = null;
public final Hashtable getLog() {
return log;
}
Context() {
log = new Hashtable(15);
bos = new ByteArrayOutputStream(256);
}
}
/**
* The OOS_STREAM_HEADER allows to reset an ObjectOutputStream built on top of
* a ByteArrayOutputStream.
*/
static protected final byte[] OOS_STREAM_HEADER = {
(byte)((ObjectStreamConstants.STREAM_MAGIC >>> 8) & 0xFF),
(byte)((ObjectStreamConstants.STREAM_MAGIC >>> 0) & 0xFF),
(byte)((ObjectStreamConstants.STREAM_VERSION >>> 8) & 0xFF),
(byte)((ObjectStreamConstants.STREAM_VERSION >>> 0) & 0xFF)
};
/**
* Register the state of a newly created object in the current transaction.
*
* @param obj the object to store.
* @param name the name of the object.
*
* @see fr.dyade.aaa.util.Transaction#create(java.io.Serializable, java.lang.String)
*/
public final void create(Serializable obj, String name) throws IOException {
save(obj, null, name, true);
}
/**
* Register the state of a newly created object in the current transaction.
*
* @param obj the object to store.
* @param dirName the directory name of the object.
* @param name the name of the object.
*
* @see fr.dyade.aaa.util.Transaction#create(java.io.Serializable, java.lang.String, java.lang.String)
*/
public final void create(Serializable obj,
String dirName, String name) throws IOException {
save(obj, dirName, name, true);
}
/**
* Register the modified state of an object in the current transaction.
*
* @param obj the object to store.
* @param name the name of the object.
*
* @see fr.dyade.aaa.util.Transaction#save(java.io.Serializable, java.lang.String)
*/
public final void save(Serializable obj, String name) throws IOException {
save(obj, null, name, false);
}
/**
* Register the modified state of an object in the current transaction.
*
* @param obj the object to store.
* @param dirName the directory name of the object.
* @param name the name of the object.
*
* @see fr.dyade.aaa.util.Transaction#save(java.io.Serializable, java.lang.String, java.lang.String)
*/
public final void save(Serializable obj,
String dirName, String name) throws IOException {
save(obj, dirName, name, false);
}
private Encodable isEncodable(Object object) {
if (object instanceof Encodable) {
Encodable encodable = (Encodable) object;
if (encodable.getEncodableClassId() >= 0) {
return encodable;
} else {
return null;
}
} else {
return null;
}
}
private byte[] serialize(Serializable obj, Context ctx) throws IOException {
if (ctx.oos == null) {
ctx.bos.reset();
if (! onlyUseJavaSerialization) {
ctx.bos.write(JAVA_SERIALIZATION_TAG);
}
ctx.oos = new ObjectOutputStream(ctx.bos);
} else {
ctx.oos.reset();
ctx.bos.reset();
if (! onlyUseJavaSerialization) {
ctx.bos.write(JAVA_SERIALIZATION_TAG);
}
ctx.bos.write(OOS_STREAM_HEADER, 0, 4);
}
ctx.oos.writeObject(obj);
ctx.oos.flush();
return ctx.bos.toByteArray();
}
/**
* Register the state of an object in the current transaction.
*
* @param obj the object to store.
* @param dirName the directory name of the object.
* @param name the name of the object.
* @param first the object is a new one.
*
* @see fr.dyade.aaa.util.Transaction#save(java.io.Serializable, java.lang.String, java.lang.String, boolean)
*/
public final void save(Serializable obj,
String dirName, String name,
boolean first) throws IOException {
Context ctx = perThreadContext.get();
byte[] encodedObject;
if (onlyUseJavaSerialization) {
encodedObject = serialize(obj, ctx);
} else {
Encodable encodable = isEncodable(obj);
if (encodable == null) {
encodedObject = serialize(obj, ctx);
} else {
try {
encodedObject = new byte[Encodable.BYTE_ENCODED_SIZE
+ Encodable.INT_ENCODED_SIZE + encodable.getEncodedSize()];
ByteBuffer buf = ByteBuffer.wrap(encodedObject);
ByteBufferEncoder encoder = new ByteBufferEncoder(buf);
encoder.encodeByte(ENCODING_TAG);
encoder.encode32(encodable.getEncodableClassId());
encodable.encode(encoder);
} catch (Exception exc) {
throw new IOException(exc);
}
}
}
saveInLog(encodedObject, dirName, name, ctx.log, false, first);
}
/**
* Register a new byte array in the current transaction.
*
* @param buf the byte array to store.
* @param name the name of the object.
*
* @see fr.dyade.aaa.util.Transaction#createByteArray(byte[], java.lang.String)
*/
public final void createByteArray(byte[] buf, String name) throws IOException {
saveByteArray(buf, null, name, true, true);
}
/**
* Register a new byte array in the current transaction.
*
* @param buf the byte array to store.
* @param dirName the directory name of the object.
* @param name the name of the object.
*
* @see fr.dyade.aaa.util.Transaction#createByteArray(byte[], java.lang.String, java.lang.String)
*/
public final void createByteArray(byte[] buf,
String dirName, String name) throws IOException {
saveByteArray(buf, dirName, name, true, true);
}
/**
* Register a modified byte array in the current transaction.
*
* @param buf the byte array to store.
* @param name the name of the object.
*
* @see fr.dyade.aaa.util.Transaction#saveByteArray(byte[], java.lang.String)
*/
public final void saveByteArray(byte[] buf, String name) throws IOException {
saveByteArray(buf, null, name, true, false);
}
/**
* Register a modified byte array in the current transaction.
*
* @param buf the byte array to store.
* @param dirName the directory name of the object.
* @param name the name of the object.
*
* @see fr.dyade.aaa.util.Transaction#saveByteArray(byte[], java.lang.String, java.lang.String)
*/
public final void saveByteArray(byte[] buf,
String dirName, String name) throws IOException {
saveByteArray(buf, dirName, name, true, false);
}
/**
* Register a modified byte array in the current transaction.
*
* @param buf the byte array to store.
* @param dirName the directory name of the object.
* @param name the name of the object.
* @param copy the byte array can be modified, copy it.
* @param first the object is a new one.
*
* @see fr.dyade.aaa.util.Transaction#saveByteArray(byte[], java.lang.String, java.lang.String, boolean, boolean)
*/
public final void saveByteArray(byte[] buf,
String dirName, String name,
boolean copy,
boolean first) throws IOException {
saveInLog(buf, dirName, name, perThreadContext.get().log, copy, first);
}
/**
* Register the specified object in transaction log.
*
* @param buf the byte array containing the state of the object.
* @param dirName the directory name of the object.
* @param name the name of the object.
* @param log the log to use.
* @param copy the byte array can be modified, copy it.
* @param first the object is a new one.
* @throws IOException
*/
protected abstract void saveInLog(byte[] buf,
String dirName, String name,
Hashtable log,
boolean copy,
boolean first) throws IOException;
/**
* Load the specified object.
*
* @param name the name of the object.
* @return the loaded object.
*
* @see fr.dyade.aaa.util.Transaction#load(java.lang.String)
*/
public final Object load(String name) throws IOException, ClassNotFoundException {
return load(null, name);
}
/**
* Load the specified object.
*
* @param dirName the directory name of the object.
* @param name the name of the object.
* @return the loaded object.
*
* @see fr.dyade.aaa.util.Transaction#load(java.lang.String, java.lang.String)
*/
public final Object load(String dirName, String name) throws IOException, ClassNotFoundException {
byte[] buf = loadByteArray(dirName, name);
if (buf != null) {
if (onlyUseJavaSerialization) {
return deserialize(buf, 0);
} else if (buf.length > 0) {
byte tag = buf[0];
switch (tag) {
case JAVA_SERIALIZATION_TAG:
return deserialize(buf, 1);
case ENCODING_TAG:
return decode(buf, 1);
default:
throw new IOException("Unexpected tag: " + tag);
}
} else {
throw new IOException("Unexpected empty byte array");
}
} else {
return null;
}
}
private Object deserialize(byte[] buf, int offset) throws IOException, ClassNotFoundException {
ByteArrayInputStream bis = new ByteArrayInputStream(buf, offset, buf.length - offset);
ObjectInputStream ois = new ObjectInputStream(bis);
try {
return ois.readObject();
} finally {
ois.close();
bis.close();
}
}
private Object decode(byte[] buf, int offset) throws IOException {
ByteBuffer byteBuffer = ByteBuffer.wrap(buf, offset, buf.length - offset);
ByteBufferDecoder decoder = new ByteBufferDecoder(byteBuffer);
try {
int classId = decoder.decode32();
EncodableFactory factory = EncodableFactoryRepository.getFactory(classId);
if (factory == null) throw new Exception("Unknown factory: " + classId);
Encodable encodable = factory.createEncodable();
encodable.decode(decoder);
return encodable;
} catch (Exception exc) {
throw new IOException(exc);
}
}
/**
* Load the specified byte array.
*
* @param name the name of the object.
* @return the loaded byte array.
*
* @see fr.dyade.aaa.util.Transaction#loadByteArray(java.lang.String)
*/
public final byte[] loadByteArray(String name) throws IOException {
return loadByteArray(null, name);
}
/**
* Deletes the specified object.
*
* @param name the name of the object.
*
* @see fr.dyade.aaa.util.Transaction#delete(java.lang.String)
*/
public final void delete(String name) {
delete(null, name);
}
/**
* Release the mutual exclusion.
* @see fr.dyade.aaa.util.Transaction#release()
*/
public synchronized void release() throws IOException {
if ((phase != RUN) && (phase != COMMIT) && (phase != ROLLBACK))
throw new IllegalStateException("Can not release transaction: " + getPhaseInfo() + '.');
// Change the transaction state.
setPhase(FREE);
// wake-up an eventually user's thread in begin
notify();
}
/**
* Indicates whether some operations have been done in
* this transaction.
*/
public boolean containsOperations() {
return (perThreadContext.get().getLog().size() > 0);
}
/**
* Returns the number of operations to be committed.
* @return the number of operations to be committed.
*/
public int getOperationCount() {
return perThreadContext.get().getLog().size();
}
}
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