/**
* 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.processor;
import java.util.ArrayList;
import java.util.Collections;
import java.util.List;
import java.util.Map;
import org.apache.camel.AsyncCallback;
import org.apache.camel.AsyncProcessor;
import org.apache.camel.CamelContext;
import org.apache.camel.CamelContextAware;
import org.apache.camel.Channel;
import org.apache.camel.Exchange;
import org.apache.camel.Processor;
import org.apache.camel.Service;
import org.apache.camel.impl.ServiceSupport;
import org.apache.camel.impl.converter.AsyncProcessorTypeConverter;
import org.apache.camel.model.ProcessorDefinition;
import org.apache.camel.processor.interceptor.StreamCaching;
import org.apache.camel.processor.interceptor.TraceFormatter;
import org.apache.camel.processor.interceptor.TraceInterceptor;
import org.apache.camel.processor.interceptor.Tracer;
import org.apache.camel.spi.InterceptStrategy;
import org.apache.camel.spi.LifecycleStrategy;
import org.apache.camel.spi.RouteContext;
import org.apache.camel.util.AsyncProcessorHelper;
import org.apache.camel.util.OrderedComparator;
import org.apache.camel.util.ServiceHelper;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
/**
* DefaultChannel is the default {@link Channel}.
* <p/>
* The current implementation is just a composite containing the interceptors and error handler
* that beforehand was added to the route graph directly.
* <br/>
* With this {@link Channel} we can in the future implement better strategies for routing the
* {@link Exchange} in the route graph, as we have a {@link Channel} between each and every node
* in the graph.
*
* @version
*/
public class DefaultChannel extends ServiceSupport implements Channel {
private static final transient Logger LOG = LoggerFactory.getLogger(DefaultChannel.class);
private final List<InterceptStrategy> interceptors = new ArrayList<InterceptStrategy>();
private Processor errorHandler;
// the next processor (non wrapped)
private Processor nextProcessor;
// the real output to invoke that has been wrapped
private Processor output;
private ProcessorDefinition<?> definition;
private ProcessorDefinition<?> childDefinition;
private CamelContext camelContext;
private RouteContext routeContext;
public List<Processor> next() {
List<Processor> answer = new ArrayList<Processor>(1);
answer.add(nextProcessor);
return answer;
}
public boolean hasNext() {
return nextProcessor != null;
}
public void setNextProcessor(Processor next) {
this.nextProcessor = next;
}
public Processor getOutput() {
// the errorHandler is already decorated with interceptors
// so it contain the entire chain of processors, so we can safely use it directly as output
// if no error handler provided we use the output
// TODO: Camel 3.0 we should determine the output dynamically at runtime instead of having the
// the error handlers, interceptors, etc. woven in at design time
return errorHandler != null ? errorHandler : output;
}
public void setOutput(Processor output) {
this.output = output;
}
public Processor getNextProcessor() {
return nextProcessor;
}
public boolean hasInterceptorStrategy(Class<?> type) {
for (InterceptStrategy strategy : interceptors) {
if (type.isInstance(strategy)) {
return true;
}
}
return false;
}
public void setErrorHandler(Processor errorHandler) {
this.errorHandler = errorHandler;
}
public Processor getErrorHandler() {
return errorHandler;
}
public void addInterceptStrategy(InterceptStrategy strategy) {
interceptors.add(strategy);
}
public void addInterceptStrategies(List<InterceptStrategy> strategies) {
interceptors.addAll(strategies);
}
public List<InterceptStrategy> getInterceptStrategies() {
return interceptors;
}
public ProcessorDefinition<?> getProcessorDefinition() {
return definition;
}
public void setChildDefinition(ProcessorDefinition<?> childDefinition) {
this.childDefinition = childDefinition;
}
public RouteContext getRouteContext() {
return routeContext;
}
@Override
protected void doStart() throws Exception {
ServiceHelper.startServices(errorHandler, output);
}
@Override
protected void doStop() throws Exception {
ServiceHelper.stopServices(output, errorHandler);
}
@SuppressWarnings("unchecked")
public void initChannel(ProcessorDefinition<?> outputDefinition, RouteContext routeContext) throws Exception {
this.routeContext = routeContext;
this.definition = outputDefinition;
this.camelContext = routeContext.getCamelContext();
Processor target = nextProcessor;
Processor next;
// init CamelContextAware as early as possible on target
if (target instanceof CamelContextAware) {
((CamelContextAware) target).setCamelContext(camelContext);
}
// the definition to wrap should be the fine grained,
// so if a child is set then use it, if not then its the original output used
ProcessorDefinition<?> targetOutputDef = childDefinition != null ? childDefinition : outputDefinition;
LOG.debug("Initialize channel for target: '{}'", targetOutputDef);
// fix parent/child relationship. This will be the case of the routes has been
// defined using XML DSL or end user may have manually assembled a route from the model.
// Background note: parent/child relationship is assembled on-the-fly when using Java DSL (fluent builders)
// where as when using XML DSL (JAXB) then it fixed after, but if people are using custom interceptors
// then we need to fix the parent/child relationship beforehand, and thus we can do it here
// ideally we need the design time route -> runtime route to be a 2-phase pass (scheduled work for Camel 3.0)
if (childDefinition != null && outputDefinition != childDefinition) {
childDefinition.setParent(outputDefinition);
}
// first wrap the output with the managed strategy if any
InterceptStrategy managed = routeContext.getManagedInterceptStrategy();
if (managed != null) {
next = target == nextProcessor ? null : nextProcessor;
target = managed.wrapProcessorInInterceptors(routeContext.getCamelContext(), targetOutputDef, target, next);
}
// then wrap the output with the tracer
TraceInterceptor trace = (TraceInterceptor) getOrCreateTracer().wrapProcessorInInterceptors(routeContext.getCamelContext(), targetOutputDef, target, null);
// trace interceptor need to have a reference to route context so we at runtime can enable/disable tracing on-the-fly
trace.setRouteContext(routeContext);
target = trace;
// sort interceptors according to ordered
Collections.sort(interceptors, new OrderedComparator());
// then reverse list so the first will be wrapped last, as it would then be first being invoked
Collections.reverse(interceptors);
// wrap the output with the configured interceptors
for (InterceptStrategy strategy : interceptors) {
next = target == nextProcessor ? null : nextProcessor;
// skip tracer as we did the specially beforehand and it could potentially be added as an interceptor strategy
if (strategy instanceof Tracer) {
continue;
}
// skip stream caching as it must be wrapped as outer most, which we do later
if (strategy instanceof StreamCaching) {
continue;
}
// use the fine grained definition (eg the child if available). Its always possible to get back to the parent
Processor wrapped = strategy.wrapProcessorInInterceptors(routeContext.getCamelContext(), targetOutputDef, target, next);
if (!(wrapped instanceof AsyncProcessor)) {
LOG.warn("Interceptor: " + strategy + " at: " + outputDefinition + " does not return an AsyncProcessor instance."
+ " This causes the asynchronous routing engine to not work as optimal as possible."
+ " See more details at the InterceptStrategy javadoc."
+ " Camel will use a bridge to adapt the interceptor to the asynchronous routing engine,"
+ " but its not the most optimal solution. Please consider changing your interceptor to comply.");
// use a bridge and wrap again which allows us to adapt and leverage the asynchronous routing engine anyway
// however its not the most optimal solution, but we can still run.
InterceptorToAsyncProcessorBridge bridge = new InterceptorToAsyncProcessorBridge(target);
wrapped = strategy.wrapProcessorInInterceptors(routeContext.getCamelContext(), targetOutputDef, bridge, next);
bridge.setTarget(wrapped);
wrapped = bridge;
}
target = wrapped;
}
// sets the delegate to our wrapped output
output = target;
}
@Override
public void postInitChannel(ProcessorDefinition<?> outputDefinition, RouteContext routeContext) throws Exception {
for (InterceptStrategy strategy : interceptors) {
// apply stream caching at the end as it should be outer most
if (strategy instanceof StreamCaching) {
if (errorHandler != null) {
errorHandler = strategy.wrapProcessorInInterceptors(routeContext.getCamelContext(), outputDefinition, errorHandler, null);
} else {
output = strategy.wrapProcessorInInterceptors(routeContext.getCamelContext(), outputDefinition, output, null);
}
break;
}
}
}
private InterceptStrategy getOrCreateTracer() {
InterceptStrategy tracer = Tracer.getTracer(camelContext);
if (tracer == null) {
if (camelContext.getRegistry() != null) {
// lookup in registry
Map<String, Tracer> map = camelContext.getRegistry().lookupByType(Tracer.class);
if (map.size() == 1) {
tracer = map.values().iterator().next();
}
}
if (tracer == null) {
// fallback to use the default tracer
tracer = camelContext.getDefaultTracer();
// configure and use any trace formatter if any exists
Map<String, TraceFormatter> formatters = camelContext.getRegistry().lookupByType(TraceFormatter.class);
if (formatters.size() == 1) {
TraceFormatter formatter = formatters.values().iterator().next();
if (tracer instanceof Tracer) {
((Tracer) tracer).setFormatter(formatter);
}
}
}
}
// which we must manage as well
for (LifecycleStrategy strategy : camelContext.getLifecycleStrategies()) {
if (tracer instanceof Service) {
strategy.onServiceAdd(camelContext, (Service) tracer, null);
}
}
return tracer;
}
public void process(Exchange exchange) throws Exception {
AsyncProcessorHelper.process(this, exchange);
}
public boolean process(final Exchange exchange, final AsyncCallback callback) {
Processor processor = getOutput();
if (processor == null || !continueProcessing(exchange)) {
// we should not continue routing so we are done
callback.done(true);
return true;
}
// push the current route context
if (exchange.getUnitOfWork() != null) {
exchange.getUnitOfWork().pushRouteContext(routeContext);
}
AsyncProcessor async = AsyncProcessorTypeConverter.convert(processor);
boolean sync = async.process(exchange, new AsyncCallback() {
public void done(boolean doneSync) {
// pop the route context we just used
if (exchange.getUnitOfWork() != null) {
exchange.getUnitOfWork().popRouteContext();
}
callback.done(doneSync);
}
});
return sync;
}
/**
* Strategy to determine if we should continue processing the {@link Exchange}.
*/
protected boolean continueProcessing(Exchange exchange) {
Object stop = exchange.getProperty(Exchange.ROUTE_STOP);
if (stop != null) {
boolean doStop = exchange.getContext().getTypeConverter().convertTo(Boolean.class, stop);
if (doStop) {
LOG.debug("Exchange is marked to stop routing: {}", exchange);
return false;
}
}
return true;
}
@Override
public String toString() {
// just output the next processor as all the interceptors and error handler is just too verbose
return "Channel[" + nextProcessor + "]";
}
}