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The Core Camel Java DSL based router
/**
* 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.Iterator;
import java.util.List;
import org.apache.camel.AsyncCallback;
import org.apache.camel.AsyncProcessor;
import org.apache.camel.Exchange;
import org.apache.camel.Navigate;
import org.apache.camel.Processor;
import org.apache.camel.Traceable;
import org.apache.camel.spi.IdAware;
import org.apache.camel.support.ServiceSupport;
import org.apache.camel.util.AsyncProcessorConverterHelper;
import org.apache.camel.util.AsyncProcessorHelper;
import org.apache.camel.util.ServiceHelper;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import static org.apache.camel.processor.PipelineHelper.continueProcessing;
/**
* Implements a Choice structure where one or more predicates are used which if
* they are true their processors are used, with a default otherwise clause used
* if none match.
*
* @version
*/
public class ChoiceProcessor extends ServiceSupport implements AsyncProcessor, Navigate, Traceable, IdAware {
private static final Logger LOG = LoggerFactory.getLogger(ChoiceProcessor.class);
private String id;
private final List filters;
private final Processor otherwise;
private transient long notFiltered;
public ChoiceProcessor(List filters, Processor otherwise) {
this.filters = filters;
this.otherwise = otherwise;
}
public void process(Exchange exchange) throws Exception {
AsyncProcessorHelper.process(this, exchange);
}
public boolean process(final Exchange exchange, final AsyncCallback callback) {
Iterator processors = next().iterator();
// callback to restore existing FILTER_MATCHED property on the Exchange
final Object existing = exchange.getProperty(Exchange.FILTER_MATCHED);
final AsyncCallback choiceCallback = new AsyncCallback() {
@Override
public void done(boolean doneSync) {
if (existing != null) {
exchange.setProperty(Exchange.FILTER_MATCHED, existing);
} else {
exchange.removeProperty(Exchange.FILTER_MATCHED);
}
callback.done(doneSync);
}
};
// as we only pick one processor to process, then no need to have async callback that has a while loop as well
// as this should not happen, eg we pick the first filter processor that matches, or the otherwise (if present)
// and if not, we just continue without using any processor
while (processors.hasNext()) {
// get the next processor
Processor processor = processors.next();
// evaluate the predicate on filter predicate early to be faster
// and avoid issues when having nested choices
// as we should only pick one processor
boolean matches = false;
if (processor instanceof FilterProcessor) {
FilterProcessor filter = (FilterProcessor) processor;
try {
matches = filter.matches(exchange);
// as we have pre evaluated the predicate then use its processor directly when routing
processor = filter.getProcessor();
} catch (Throwable e) {
exchange.setException(e);
}
} else {
// its the otherwise processor, so its a match
notFiltered++;
matches = true;
}
// check for error if so we should break out
if (!continueProcessing(exchange, "so breaking out of choice", LOG)) {
break;
}
// if we did not match then continue to next filter
if (!matches) {
continue;
}
// okay we found a filter or its the otherwise we are processing
AsyncProcessor async = AsyncProcessorConverterHelper.convert(processor);
return async.process(exchange, choiceCallback);
}
// when no filter matches and there is no otherwise, then just continue
choiceCallback.done(true);
return true;
}
@Override
public String toString() {
StringBuilder builder = new StringBuilder("choice{");
boolean first = true;
for (Processor processor : filters) {
if (first) {
first = false;
} else {
builder.append(", ");
}
builder.append("when ");
builder.append(processor);
}
if (otherwise != null) {
builder.append(", otherwise: ");
builder.append(otherwise);
}
builder.append("}");
return builder.toString();
}
public String getTraceLabel() {
return "choice";
}
public List getFilters() {
return filters;
}
public Processor getOtherwise() {
return otherwise;
}
/**
* Gets the number of Exchanges that did not match any predicate and are routed using otherwise
*/
public long getNotFilteredCount() {
return notFiltered;
}
/**
* Reset counters.
*/
public void reset() {
for (FilterProcessor filter : getFilters()) {
filter.reset();
}
notFiltered = 0;
}
public List next() {
if (!hasNext()) {
return null;
}
List answer = new ArrayList<>();
if (filters != null) {
answer.addAll(filters);
}
if (otherwise != null) {
answer.add(otherwise);
}
return answer;
}
public boolean hasNext() {
return otherwise != null || (filters != null && !filters.isEmpty());
}
public String getId() {
return id;
}
public void setId(String id) {
this.id = id;
}
protected void doStart() throws Exception {
ServiceHelper.startServices(filters, otherwise);
}
protected void doStop() throws Exception {
ServiceHelper.stopServices(otherwise, filters);
}
}