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// Copyright (c) 2003-present, Jodd Team (http://jodd.org)
// All rights reserved.
//
// Redistribution and use in source and binary forms, with or without
// modification, are permitted provided that the following conditions are met:
//
// 1. Redistributions of source code must retain the above copyright notice,
// this list of conditions and the following disclaimer.
//
// 2. Redistributions in binary form must reproduce the above copyright
// notice, this list of conditions and the following disclaimer in the
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//
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// ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
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package jodd.jtx;
import jodd.log.Logger;
import jodd.log.LoggerFactory;
import java.util.HashSet;
import java.util.Iterator;
import java.util.Set;
import static jodd.jtx.JtxStatus.STATUS_ACTIVE;
import static jodd.jtx.JtxStatus.STATUS_COMMITTED;
import static jodd.jtx.JtxStatus.STATUS_COMMITTING;
import static jodd.jtx.JtxStatus.STATUS_MARKED_ROLLBACK;
import static jodd.jtx.JtxStatus.STATUS_NO_TRANSACTION;
import static jodd.jtx.JtxStatus.STATUS_ROLLEDBACK;
import static jodd.jtx.JtxStatus.STATUS_ROLLING_BACK;
import static jodd.jtx.JtxStatus.STATUS_UNKNOWN;
import static jodd.jtx.JtxTransactionMode.DEFAULT_TIMEOUT;
/**
* Transaction is an unit of work that is performed by one or more resources.
* Created and controlled by {@link JtxTransactionManager transaction manager}.
*
* Transaction is associated to a thread from where it was created.
* Transaction may have more than one resource attached.
*
* Committing and rolling back transaction actually performs commit/rollback on
* all attached resources. Therefore, it may happens that committing of one resource
* fails, what actually breaks the atomicity of the transaction. If transaction is
* attached just to one resource, atomicity is saved.
*
* Only one resource of some type may exists in the transaction. There is no way to have
* two resources of the same type in one transaction.
*
* This class is responsible for transaction life-cycle. It can be consider that all
* work is scoped to associated thread.
*/
public class JtxTransaction {
private static final Logger log = LoggerFactory.getLogger(JtxTransaction.class);
// ---------------------------------------------------------------- init
protected final JtxTransactionManager txManager;
protected final JtxTransactionMode mode;
protected final Set resources;
protected final Object scope;
protected final long deadline;
protected final boolean startAsActive;
protected Throwable rollbackCause;
protected JtxStatus status;
/**
* Creates new transaction. Should be invoked by {@link jodd.jtx.JtxTransactionManager}.
* If transaction is set as active, it will be actually created, meaning
* that it is the first transaction on this connection i.e. in this session.
* If transaction is not active, transaction object will be created,
* but the real transaction not, and it is expected that one is already created before.
*
* @param txManager jtx manager
* @param mode transaction mode
* @param scope transaction live scope within the other transaction requests are ignored
* @param active if true it is an active transaction, otherwise it's not
*/
public JtxTransaction(final JtxTransactionManager txManager, final JtxTransactionMode mode, final Object scope, final boolean active) {
this.txManager = txManager;
this.mode = mode;
this.scope = scope;
this.resources = new HashSet<>();
this.deadline = mode.getTransactionTimeout() == DEFAULT_TIMEOUT ?
DEFAULT_TIMEOUT :
System.currentTimeMillis() + (mode.getTransactionTimeout() * 1000L);
this.status = active ? STATUS_ACTIVE : STATUS_NO_TRANSACTION;
this.startAsActive = active;
txManager.associateTransaction(this);
if (log.isDebugEnabled()) {
log.debug("New JTX {status:" + this.status + ", mode:" + this.mode + '}');
}
}
/**
* Returns transaction mode.
*/
public JtxTransactionMode getTransactionMode() {
return mode;
}
/**
* Returns transaction manager that owns this transaction.
*/
public JtxTransactionManager getTransactionManager() {
return txManager;
}
/**
* Returns transaction scope if exist, or null.
*/
public Object getScope() {
return scope;
}
// ---------------------------------------------------------------- status
/**
* Returns current transaction status.
*/
public JtxStatus getStatus() {
return status;
}
/**
* Returns true if transaction started as active one.
* This value is never changed, while {@link #getStatus() status}
* changes during the execution.
*/
public boolean isStartAsActive() {
return startAsActive;
}
/**
* Returns true if transaction is active.
* This status changes during the transaction flow.
*/
public boolean isActive() {
return status == STATUS_ACTIVE;
}
/**
* Returns true if transaction is explicitly forbidden, i.e.
* session is in auto-commit mode.
*/
public boolean isNoTransaction() {
return status == STATUS_NO_TRANSACTION;
}
/**
* Returns true if transaction and all its resources are committed successfully.
*/
public boolean isCommitted() {
return status == STATUS_COMMITTED;
}
/**
* Returns true if transaction and all its resources are rolled-back successfully.
*/
public boolean isRolledback() {
return status == STATUS_ROLLEDBACK;
}
/**
* Returns true if transaction is either committed or rolled back.
*/
public boolean isCompleted() {
return status == STATUS_COMMITTED || status == STATUS_ROLLEDBACK;
}
// ---------------------------------------------------------------- rollback
/**
* Modify the transaction associated with the target object such that the only possible outcome
* of the transaction is to roll back the transaction.
*/
public void setRollbackOnly() {
setRollbackOnly(null);
}
/**
* Modify the transaction associated with the target object such that the only possible outcome
* of the transaction is to roll back the transaction.
*/
public void setRollbackOnly(final Throwable th) {
if (!isNoTransaction()) {
if ((status != STATUS_MARKED_ROLLBACK) && (status != STATUS_ACTIVE)) {
throw new JtxException("TNo active TX that can be marked as rollback only");
}
}
rollbackCause = th;
status = STATUS_MARKED_ROLLBACK;
}
/**
* Returns true if transaction is marked as rollback only.
*/
public boolean isRollbackOnly() {
return status == STATUS_MARKED_ROLLBACK;
}
// ---------------------------------------------------------------- timeout
/**
* Sets the rollback-only if the deadline has been reached and throws an exception.
*/
protected void checkTimeout() {
if (deadline == DEFAULT_TIMEOUT) {
return;
}
if (this.deadline - System.currentTimeMillis() < 0) {
setRollbackOnly();
throw new JtxException("TX timed out, marked as rollback only");
}
}
// ---------------------------------------------------------------- core
/**
* Commit and completes current transaction. Transaction is committed on all attached resources. After, resources
* are detached from the transaction. When this method completes,transaction is no longer
* associated with current thread.
*/
public void commit() {
checkTimeout();
commitOrRollback(true);
}
/**
* Roll back and completes current transaction. Transaction is rolled back on all attached resources.
* Resource are then detached from the transaction. When this method completes, transaction is no
* longer associated with current thread.
*/
public void rollback() {
commitOrRollback(false);
}
/**
* Performs either commit or rollback on all transaction resources.
*/
protected void commitOrRollback(boolean doCommit) {
if (log.isDebugEnabled()) {
if (doCommit) {
log.debug("Commit JTX");
} else {
log.debug("Rollback JTX");
}
}
boolean forcedRollback = false;
if (!isNoTransaction()) {
if (isRollbackOnly()) {
if (doCommit) {
doCommit = false;
forcedRollback = true;
}
} else if (!isActive()) {
if (isCompleted()) {
throw new JtxException("TX is already completed, commit or rollback should be called once per TX");
}
throw new JtxException("No active TX to " + (doCommit ? "commit" : "rollback"));
}
}
if (doCommit) {
commitAllResources();
} else {
rollbackAllResources(forcedRollback);
}
}
// ---------------------------------------------------------------- resources
/**
* Commits all attached resources. On successful commit, resource will be closed
* and detached from this transaction. On exception, resource remains attached
* to transaction.
*
* All resources will be committed, even if commit fails on some in that process.
* If there was at least one failed commit, its exception will be re-thrown after finishing
* committing all resources, and transaction will be marked as rollback only.
*/
protected void commitAllResources() throws JtxException {
status = STATUS_COMMITTING;
Exception lastException = null;
Iterator it = resources.iterator();
while (it.hasNext()) {
JtxResource resource = it.next();
try {
resource.commitTransaction();
it.remove();
} catch (Exception ex) {
lastException = ex;
}
}
if (lastException != null) {
setRollbackOnly(lastException);
throw new JtxException("Commit failed: one or more TX resources couldn't commit a TX", lastException);
}
txManager.removeTransaction(this);
status = STATUS_COMMITTED;
}
/**
* Rollbacks all attached resources. Resource will be closed. and detached from this transaction.
* If exception occurs, it will be rethrown at the end.
*/
protected void rollbackAllResources(final boolean wasForced) {
status = STATUS_ROLLING_BACK;
Exception lastException = null;
Iterator it = resources.iterator();
while (it.hasNext()) {
JtxResource resource = it.next();
try {
resource.rollbackTransaction();
} catch (Exception ex) {
lastException = ex;
} finally {
it.remove();
}
}
txManager.removeTransaction(this);
status = STATUS_ROLLEDBACK;
if (lastException != null) {
status = STATUS_UNKNOWN;
throw new JtxException("Rollback failed: one or more TX resources couldn't rollback a TX", lastException);
}
if (wasForced) {
throw new JtxException("TX rolled back because it has been marked as rollback-only", rollbackCause);
}
}
// ---------------------------------------------------------------- resources
/**
* Requests a resource. If resource is not found, it will be created and new transaction will be started on it.
*/
public E requestResource(final Class resourceType) {
if (isCompleted()) {
throw new JtxException("TX is already completed, resource are not available after commit or rollback");
}
if (isRollbackOnly()) {
throw new JtxException("TX is marked as rollback only, resource are not available", rollbackCause);
}
if (!isNoTransaction() && !isActive()) {
throw new JtxException("Resources are not available since TX is not active");
}
checkTimeout();
E resource = lookupResource(resourceType);
if (resource == null) {
int maxResources = txManager.getMaxResourcesPerTransaction();
if ((maxResources != -1) && (resources.size() >= maxResources)) {
throw new JtxException("TX already has attached max. number of resources");
}
JtxResourceManager resourceManager = txManager.lookupResourceManager(resourceType);
resource = resourceManager.beginTransaction(mode, isActive());
resources.add(new JtxResource<>(this, resourceManager, resource));
}
return resource;
}
/**
* Lookups for open resource. Returns null if resource not found.
* Only open resources can be found.
*/
protected E lookupResource(final Class resourceType) {
for (JtxResource jtxResource : resources) {
if (jtxResource.isSameTypeAsResource(resourceType)) {
//noinspection unchecked
return (E) jtxResource.getResource();
}
}
return null;
}
}