/**
* 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.model;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.Collection;
import java.util.List;
import javax.xml.bind.annotation.XmlAccessType;
import javax.xml.bind.annotation.XmlAccessorType;
import javax.xml.bind.annotation.XmlAttribute;
import javax.xml.bind.annotation.XmlElement;
import javax.xml.bind.annotation.XmlElementRef;
import javax.xml.bind.annotation.XmlElements;
import javax.xml.bind.annotation.XmlRootElement;
import org.apache.camel.Expression;
import org.apache.camel.Processor;
import org.apache.camel.model.loadbalancer.CircuitBreakerLoadBalancerDefinition;
import org.apache.camel.model.loadbalancer.CustomLoadBalancerDefinition;
import org.apache.camel.model.loadbalancer.FailoverLoadBalancerDefinition;
import org.apache.camel.model.loadbalancer.RandomLoadBalancerDefinition;
import org.apache.camel.model.loadbalancer.RoundRobinLoadBalancerDefinition;
import org.apache.camel.model.loadbalancer.StickyLoadBalancerDefinition;
import org.apache.camel.model.loadbalancer.TopicLoadBalancerDefinition;
import org.apache.camel.model.loadbalancer.WeightedLoadBalancerDefinition;
import org.apache.camel.processor.loadbalancer.CircuitBreakerLoadBalancer;
import org.apache.camel.processor.loadbalancer.FailOverLoadBalancer;
import org.apache.camel.processor.loadbalancer.LoadBalancer;
import org.apache.camel.processor.loadbalancer.RandomLoadBalancer;
import org.apache.camel.processor.loadbalancer.RoundRobinLoadBalancer;
import org.apache.camel.processor.loadbalancer.StickyLoadBalancer;
import org.apache.camel.processor.loadbalancer.TopicLoadBalancer;
import org.apache.camel.processor.loadbalancer.WeightedLoadBalancer;
import org.apache.camel.processor.loadbalancer.WeightedRandomLoadBalancer;
import org.apache.camel.processor.loadbalancer.WeightedRoundRobinLoadBalancer;
import org.apache.camel.spi.RouteContext;
import org.apache.camel.util.CollectionStringBuffer;
/**
* Represents an XML <loadBalance/> element
*/
@XmlRootElement(name = "loadBalance")
@XmlAccessorType(XmlAccessType.FIELD)
public class LoadBalanceDefinition extends ProcessorDefinition<LoadBalanceDefinition> {
@XmlAttribute
@Deprecated
private String ref;
@XmlElements({
@XmlElement(required = false, name = "failover", type = FailoverLoadBalancerDefinition.class),
@XmlElement(required = false, name = "random", type = RandomLoadBalancerDefinition.class),
@XmlElement(required = false, name = "custom", type = CustomLoadBalancerDefinition.class),
@XmlElement(required = false, name = "roundRobin", type = RoundRobinLoadBalancerDefinition.class),
@XmlElement(required = false, name = "sticky", type = StickyLoadBalancerDefinition.class),
@XmlElement(required = false, name = "topic", type = TopicLoadBalancerDefinition.class),
@XmlElement(required = false, name = "weighted", type = WeightedLoadBalancerDefinition.class),
@XmlElement(required = false, name = "circuitBreaker", type = CircuitBreakerLoadBalancerDefinition.class)}
)
private LoadBalancerDefinition loadBalancerType;
@XmlElementRef
private List<ProcessorDefinition<?>> outputs = new ArrayList<ProcessorDefinition<?>>();
public LoadBalanceDefinition() {
}
@Override
public String getShortName() {
return "loadbalance";
}
@Override
public List<ProcessorDefinition<?>> getOutputs() {
return outputs;
}
public void setOutputs(List<ProcessorDefinition<?>> outputs) {
this.outputs = outputs;
if (outputs != null) {
for (ProcessorDefinition<?> output : outputs) {
configureChild(output);
}
}
}
public boolean isOutputSupported() {
return true;
}
public String getRef() {
return ref;
}
public void setRef(String ref) {
this.ref = ref;
}
public LoadBalancerDefinition getLoadBalancerType() {
return loadBalancerType;
}
public void setLoadBalancerType(LoadBalancerDefinition loadbalancer) {
if (loadBalancerType != null) {
throw new IllegalArgumentException("Loadbalancer already configured to: " + loadBalancerType + ". Cannot set it to: " + loadbalancer);
}
loadBalancerType = loadbalancer;
}
protected Processor createOutputsProcessor(RouteContext routeContext,
Collection<ProcessorDefinition<?>> outputs) throws Exception {
LoadBalancer loadBalancer = LoadBalancerDefinition.getLoadBalancer(routeContext, loadBalancerType, ref);
for (ProcessorDefinition<?> processorType : outputs) {
Processor processor = createProcessor(routeContext, processorType);
loadBalancer.addProcessor(processor);
}
return loadBalancer;
}
@Override
public Processor createProcessor(RouteContext routeContext) throws Exception {
LoadBalancer loadBalancer = LoadBalancerDefinition.getLoadBalancer(routeContext, loadBalancerType, ref);
for (ProcessorDefinition<?> processorType : getOutputs()) {
// output must not be another load balancer
// check for instanceof as the code below as there is compilation errors on earlier versions of JDK6
// on Windows boxes or with IBM JDKs etc.
if (LoadBalanceDefinition.class.isInstance(processorType)) {
throw new IllegalArgumentException("Loadbalancer already configured to: " + loadBalancerType + ". Cannot set it to: " + processorType);
}
Processor processor = createProcessor(routeContext, processorType);
processor = wrapChannel(routeContext, processor, processorType);
loadBalancer.addProcessor(processor);
}
return loadBalancer;
}
// Fluent API
// -------------------------------------------------------------------------
/**
* Uses a custom load balancer
*
* @param loadBalancer the load balancer
* @return the builder
*/
public LoadBalanceDefinition loadBalance(LoadBalancer loadBalancer) {
setLoadBalancerType(new LoadBalancerDefinition(loadBalancer));
return this;
}
/**
* Uses fail over load balancer
* <p/>
* Will not round robin and inherit the error handler.
*
* @return the builder
*/
public LoadBalanceDefinition failover() {
return failover(-1, true, false);
}
/**
* Uses fail over load balancer
* <p/>
* Will not round robin and inherit the error handler.
*
* @param exceptions exception classes which we want to failover if one of them was thrown
* @return the builder
*/
public LoadBalanceDefinition failover(Class<?>... exceptions) {
return failover(-1, true, false, exceptions);
}
/**
* Uses fail over load balancer
*
* @param maximumFailoverAttempts maximum number of failover attempts before exhausting.
* Use -1 to newer exhaust when round robin is also enabled.
* If round robin is disabled then it will exhaust when there are no more endpoints to failover
* @param inheritErrorHandler whether or not to inherit error handler.
* If <tt>false</tt> then it will failover immediately in case of an exception
* @param roundRobin whether or not to use round robin (which keeps state)
* @param exceptions exception classes which we want to failover if one of them was thrown
* @return the builder
*/
public LoadBalanceDefinition failover(int maximumFailoverAttempts, boolean inheritErrorHandler, boolean roundRobin, Class<?>... exceptions) {
FailOverLoadBalancer failover = new FailOverLoadBalancer(Arrays.asList(exceptions));
failover.setMaximumFailoverAttempts(maximumFailoverAttempts);
failover.setRoundRobin(roundRobin);
setLoadBalancerType(new LoadBalancerDefinition(failover));
this.setInheritErrorHandler(inheritErrorHandler);
return this;
}
/**
* Uses weighted load balancer
*
* @param roundRobin used to set the processor selection algorithm.
* @param distributionRatio String of weighted ratios for distribution of messages.
* @return the builder
*/
public LoadBalanceDefinition weighted(boolean roundRobin, String distributionRatio) {
return weighted(roundRobin, distributionRatio, ",");
}
/**
* Uses circuitBreaker load balancer
*
* @param threshold number of errors before failure.
* @param halfOpenAfter time interval in milliseconds for half open state.
* @param exceptions exception classes which we want to break if one of them was thrown
* @return the builder
*/
public LoadBalanceDefinition circuitBreaker(int threshold, long halfOpenAfter, Class<?>... exceptions) {
CircuitBreakerLoadBalancer breakerLoadBalancer = new CircuitBreakerLoadBalancer(Arrays.asList(exceptions));
breakerLoadBalancer.setThreshold(threshold);
breakerLoadBalancer.setHalfOpenAfter(halfOpenAfter);
setLoadBalancerType(new LoadBalancerDefinition(breakerLoadBalancer));
return this;
}
/**
* Uses weighted load balancer
*
* @param roundRobin used to set the processor selection algorithm.
* @param distributionRatio String of weighted ratios for distribution of messages.
* @param distributionRatioDelimiter String containing delimiter to be used for ratios
* @return the builder
*/
public LoadBalanceDefinition weighted(boolean roundRobin, String distributionRatio, String distributionRatioDelimiter) {
WeightedLoadBalancer weighted;
List<Integer> distributionRatioList = new ArrayList<Integer>();
String[] ratios = distributionRatio.split(distributionRatioDelimiter);
for (String ratio : ratios) {
distributionRatioList.add(new Integer(ratio.trim()));
}
if (!roundRobin) {
weighted = new WeightedRandomLoadBalancer(distributionRatioList);
} else {
weighted = new WeightedRoundRobinLoadBalancer(distributionRatioList);
}
setLoadBalancerType(new LoadBalancerDefinition(weighted));
return this;
}
/**
* Uses round robin load balancer
*
* @return the builder
*/
public LoadBalanceDefinition roundRobin() {
setLoadBalancerType(new LoadBalancerDefinition(new RoundRobinLoadBalancer()));
return this;
}
/**
* Uses random load balancer
*
* @return the builder
*/
public LoadBalanceDefinition random() {
setLoadBalancerType(new LoadBalancerDefinition(new RandomLoadBalancer()));
return this;
}
/**
* Uses the custom load balancer
*
* @param ref reference to lookup a custom load balancer from the {@link org.apache.camel.spi.Registry} to be used.
* @return the builder
*/
public LoadBalanceDefinition custom(String ref) {
CustomLoadBalancerDefinition balancer = new CustomLoadBalancerDefinition();
balancer.setRef(ref);
setLoadBalancerType(balancer);
return this;
}
/**
* Uses sticky load balancer
*
* @param correlationExpression the expression for correlation
* @return the builder
*/
public LoadBalanceDefinition sticky(Expression correlationExpression) {
setLoadBalancerType(new LoadBalancerDefinition(new StickyLoadBalancer(correlationExpression)));
return this;
}
/**
* Uses topic load balancer
*
* @return the builder
*/
public LoadBalanceDefinition topic() {
setLoadBalancerType(new LoadBalancerDefinition(new TopicLoadBalancer()));
return this;
}
@Override
public String getLabel() {
CollectionStringBuffer buffer = new CollectionStringBuffer("loadBalance[");
List<ProcessorDefinition<?>> list = getOutputs();
for (ProcessorDefinition<?> processorType : list) {
buffer.append(processorType.getLabel());
}
buffer.append("]");
return buffer.toString();
}
@Override
public String toString() {
if (loadBalancerType != null) {
return "LoadBalanceType[" + loadBalancerType + ", " + getOutputs() + "]";
} else {
return "LoadBalanceType[ref:" + ref + ", " + getOutputs() + "]";
}
}
}