/**
* 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.camel.impl;
import java.util.ArrayList;
import java.util.Date;
import java.util.Iterator;
import java.util.LinkedHashSet;
import java.util.List;
import java.util.Set;
import java.util.Stack;
import org.apache.camel.AsyncCallback;
import org.apache.camel.CamelContext;
import org.apache.camel.CamelUnitOfWorkException;
import org.apache.camel.Exchange;
import org.apache.camel.Message;
import org.apache.camel.Processor;
import org.apache.camel.Service;
import org.apache.camel.spi.RouteContext;
import org.apache.camel.spi.SubUnitOfWork;
import org.apache.camel.spi.SubUnitOfWorkCallback;
import org.apache.camel.spi.Synchronization;
import org.apache.camel.spi.SynchronizationVetoable;
import org.apache.camel.spi.TracedRouteNodes;
import org.apache.camel.spi.UnitOfWork;
import org.apache.camel.util.EventHelper;
import org.apache.camel.util.UnitOfWorkHelper;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
/**
* The default implementation of {@link org.apache.camel.spi.UnitOfWork}
*/
public class DefaultUnitOfWork implements UnitOfWork, Service {
private static final Logger LOG = LoggerFactory.getLogger(DefaultUnitOfWork.class);
// TODO: This implementation seems to have transformed itself into a to broad concern
// where unit of work is doing a bit more work than the transactional aspect that ties
// to its name. Maybe this implementation should be named ExchangeContext and we can
// introduce a simpler UnitOfWork concept. This would also allow us to refactor the
// SubUnitOfWork into a general parent/child unit of work concept. However this
// requires API changes and thus is best kept for Camel 3.0
private UnitOfWork parent;
private String id;
private CamelContext context;
private List<Synchronization> synchronizations;
private Message originalInMessage;
private final TracedRouteNodes tracedRouteNodes;
private Set<Object> transactedBy;
private final Stack<RouteContext> routeContextStack = new Stack<RouteContext>();
private Stack<DefaultSubUnitOfWork> subUnitOfWorks;
private final transient Logger log;
public DefaultUnitOfWork(Exchange exchange) {
this(exchange, LOG);
}
protected DefaultUnitOfWork(Exchange exchange, Logger logger) {
log = logger;
if (log.isTraceEnabled()) {
log.trace("UnitOfWork created for ExchangeId: {} with {}", exchange.getExchangeId(), exchange);
}
tracedRouteNodes = new DefaultTracedRouteNodes();
context = exchange.getContext();
if (context.isAllowUseOriginalMessage()) {
// TODO: Camel 3.0: the copy on facade strategy will help us here in the future
// TODO: optimize to only copy original message if enabled to do so in the route
// special for JmsMessage as it can cause it to loose headers later.
// This will be resolved when we get the message facade with copy on write implemented
if (exchange.getIn().getClass().getName().equals("org.apache.camel.component.jms.JmsMessage")) {
this.originalInMessage = new DefaultMessage();
this.originalInMessage.setBody(exchange.getIn().getBody());
this.originalInMessage.getHeaders().putAll(exchange.getIn().getHeaders());
} else {
this.originalInMessage = exchange.getIn().copy();
}
}
// TODO: Optimize to only copy if useOriginalMessage has been enabled
// mark the creation time when this Exchange was created
if (exchange.getProperty(Exchange.CREATED_TIMESTAMP) == null) {
exchange.setProperty(Exchange.CREATED_TIMESTAMP, new Date());
}
// inject breadcrumb header if enabled
if (exchange.getContext().isUseBreadcrumb()) {
// create or use existing breadcrumb
String breadcrumbId = exchange.getIn().getHeader(Exchange.BREADCRUMB_ID, String.class);
if (breadcrumbId == null) {
// no existing breadcrumb, so create a new one based on the message id
breadcrumbId = exchange.getIn().getMessageId();
exchange.getIn().setHeader(Exchange.BREADCRUMB_ID, breadcrumbId);
}
}
// setup whether the exchange is externally redelivered or not (if not initialized before)
// store as property so we know that the origin exchange was redelivered
if (exchange.getProperty(Exchange.EXTERNAL_REDELIVERED) == null) {
exchange.setProperty(Exchange.EXTERNAL_REDELIVERED, exchange.isExternalRedelivered());
}
// fire event
try {
EventHelper.notifyExchangeCreated(exchange.getContext(), exchange);
} catch (Throwable e) {
// must catch exceptions to ensure the exchange is not failing due to notification event failed
log.warn("Exception occurred during event notification. This exception will be ignored.", e);
}
// register to inflight registry
if (exchange.getContext() != null) {
exchange.getContext().getInflightRepository().add(exchange);
}
}
UnitOfWork newInstance(Exchange exchange) {
return new DefaultUnitOfWork(exchange);
}
@Override
public void setParentUnitOfWork(UnitOfWork parentUnitOfWork) {
this.parent = parentUnitOfWork;
}
public UnitOfWork createChildUnitOfWork(Exchange childExchange) {
// create a new child unit of work, and mark me as its parent
UnitOfWork answer = newInstance(childExchange);
answer.setParentUnitOfWork(this);
return answer;
}
public void start() throws Exception {
id = null;
}
public void stop() throws Exception {
// need to clean up when we are stopping to not leak memory
if (synchronizations != null) {
synchronizations.clear();
}
if (tracedRouteNodes != null) {
tracedRouteNodes.clear();
}
if (transactedBy != null) {
transactedBy.clear();
}
synchronized (routeContextStack) {
if (!routeContextStack.isEmpty()) {
routeContextStack.clear();
}
}
if (subUnitOfWorks != null) {
subUnitOfWorks.clear();
}
originalInMessage = null;
parent = null;
id = null;
}
public synchronized void addSynchronization(Synchronization synchronization) {
if (synchronizations == null) {
synchronizations = new ArrayList<Synchronization>();
}
log.trace("Adding synchronization {}", synchronization);
synchronizations.add(synchronization);
}
public synchronized void removeSynchronization(Synchronization synchronization) {
if (synchronizations != null) {
synchronizations.remove(synchronization);
}
}
public synchronized boolean containsSynchronization(Synchronization synchronization) {
return synchronizations != null && synchronizations.contains(synchronization);
}
public void handoverSynchronization(Exchange target) {
if (synchronizations == null || synchronizations.isEmpty()) {
return;
}
Iterator<Synchronization> it = synchronizations.iterator();
while (it.hasNext()) {
Synchronization synchronization = it.next();
boolean handover = true;
if (synchronization instanceof SynchronizationVetoable) {
SynchronizationVetoable veto = (SynchronizationVetoable) synchronization;
handover = veto.allowHandover();
}
if (handover) {
log.trace("Handover synchronization {} to: {}", synchronization, target);
target.addOnCompletion(synchronization);
// remove it if its handed over
it.remove();
} else {
log.trace("Handover not allow for synchronization {}", synchronization);
}
}
}
public void done(Exchange exchange) {
log.trace("UnitOfWork done for ExchangeId: {} with {}", exchange.getExchangeId(), exchange);
boolean failed = exchange.isFailed();
// at first done the synchronizations
UnitOfWorkHelper.doneSynchronizations(exchange, synchronizations, log);
// notify uow callback if in use
try {
SubUnitOfWorkCallback uowCallback = getSubUnitOfWorkCallback();
if (uowCallback != null) {
uowCallback.onDone(exchange);
}
} catch (Throwable e) {
// must catch exceptions to ensure synchronizations is also invoked
log.warn("Exception occurred during savepoint onDone. This exception will be ignored.", e);
}
// unregister from inflight registry, before signalling we are done
if (exchange.getContext() != null) {
exchange.getContext().getInflightRepository().remove(exchange);
}
// then fire event to signal the exchange is done
try {
if (failed) {
EventHelper.notifyExchangeFailed(exchange.getContext(), exchange);
} else {
EventHelper.notifyExchangeDone(exchange.getContext(), exchange);
}
} catch (Throwable e) {
// must catch exceptions to ensure synchronizations is also invoked
log.warn("Exception occurred during event notification. This exception will be ignored.", e);
}
}
public String getId() {
if (id == null) {
id = context.getUuidGenerator().generateUuid();
}
return id;
}
public Message getOriginalInMessage() {
return originalInMessage;
}
public TracedRouteNodes getTracedRouteNodes() {
return tracedRouteNodes;
}
public boolean isTransacted() {
return transactedBy != null && !transactedBy.isEmpty();
}
public boolean isTransactedBy(Object key) {
return getTransactedBy().contains(key);
}
public void beginTransactedBy(Object key) {
getTransactedBy().add(key);
}
public void endTransactedBy(Object key) {
getTransactedBy().remove(key);
}
public RouteContext getRouteContext() {
synchronized (routeContextStack) {
if (routeContextStack.isEmpty()) {
return null;
}
return routeContextStack.peek();
}
}
public void pushRouteContext(RouteContext routeContext) {
synchronized (routeContextStack) {
routeContextStack.add(routeContext);
}
}
public RouteContext popRouteContext() {
synchronized (routeContextStack) {
if (routeContextStack.isEmpty()) {
return null;
}
return routeContextStack.pop();
}
}
public AsyncCallback beforeProcess(Processor processor, Exchange exchange, AsyncCallback callback) {
// no wrapping needed
return callback;
}
public void afterProcess(Processor processor, Exchange exchange, AsyncCallback callback, boolean doneSync) {
}
@Override
public void beginSubUnitOfWork(Exchange exchange) {
if (log.isTraceEnabled()) {
log.trace("beginSubUnitOfWork exchangeId: {}", exchange.getExchangeId());
}
if (subUnitOfWorks == null) {
subUnitOfWorks = new Stack<DefaultSubUnitOfWork>();
}
subUnitOfWorks.push(new DefaultSubUnitOfWork());
}
@Override
public void endSubUnitOfWork(Exchange exchange) {
if (log.isTraceEnabled()) {
log.trace("endSubUnitOfWork exchangeId: {}", exchange.getExchangeId());
}
if (subUnitOfWorks == null || subUnitOfWorks.isEmpty()) {
return;
}
// pop last sub unit of work as its now ended
SubUnitOfWork subUoW = subUnitOfWorks.pop();
if (subUoW.isFailed()) {
// the sub unit of work failed so set an exception containing all the caused exceptions
// and mark the exchange for rollback only
// if there are multiple exceptions then wrap those into another exception with them all
Exception cause;
List<Exception> list = subUoW.getExceptions();
if (list != null) {
if (list.size() == 1) {
cause = list.get(0);
} else {
cause = new CamelUnitOfWorkException(exchange, list);
}
exchange.setException(cause);
}
// mark it as rollback and that the unit of work is exhausted. This ensures that we do not try
// to redeliver this exception (again)
exchange.setProperty(Exchange.ROLLBACK_ONLY, true);
exchange.setProperty(Exchange.UNIT_OF_WORK_EXHAUSTED, true);
// and remove any indications of error handled which will prevent this exception to be noticed
// by the error handler which we want to react with the result of the sub unit of work
exchange.setProperty(Exchange.ERRORHANDLER_HANDLED, null);
exchange.setProperty(Exchange.FAILURE_HANDLED, null);
if (log.isTraceEnabled()) {
log.trace("endSubUnitOfWork exchangeId: {} with {} caused exceptions.", exchange.getExchangeId(), list != null ? list.size() : 0);
}
}
}
@Override
public SubUnitOfWorkCallback getSubUnitOfWorkCallback() {
// if there is a parent-child relationship between unit of works
// then we should use the callback strategies from the parent
if (parent != null) {
return parent.getSubUnitOfWorkCallback();
}
if (subUnitOfWorks == null || subUnitOfWorks.isEmpty()) {
return null;
}
return subUnitOfWorks.peek();
}
private Set<Object> getTransactedBy() {
if (transactedBy == null) {
transactedBy = new LinkedHashSet<Object>();
}
return transactedBy;
}
@Override
public String toString() {
return "DefaultUnitOfWork";
}
}