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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.model.loadbalancer;
import java.util.ArrayList;
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.XmlRootElement;
import javax.xml.bind.annotation.XmlTransient;
import org.apache.camel.model.LoadBalancerDefinition;
import org.apache.camel.processor.loadbalancer.FailOverLoadBalancer;
import org.apache.camel.processor.loadbalancer.LoadBalancer;
import org.apache.camel.spi.Metadata;
import org.apache.camel.spi.RouteContext;
import org.apache.camel.util.ObjectHelper;
/**
* Failover load balancer
*
* The failover load balancer is capable of trying the next processor in case an Exchange failed with an exception during processing.
* You can constrain the failover to activate only when one exception of a list you specify occurs.
* If you do not specify a list any exception will cause fail over to occur.
* This balancer uses the same strategy for matching exceptions as the Exception Clause does for the onException.
*/
@Metadata(label = "eip,routing,loadbalance")
@XmlRootElement(name = "failover")
@XmlAccessorType(XmlAccessType.FIELD)
public class FailoverLoadBalancerDefinition extends LoadBalancerDefinition {
@XmlTransient
private List> exceptionTypes = new ArrayList<>();
@XmlElement(name = "exception")
private List exceptions = new ArrayList<>();
@XmlAttribute
private Boolean roundRobin;
@XmlAttribute
private Boolean sticky;
@XmlAttribute @Metadata(defaultValue = "-1")
private Integer maximumFailoverAttempts;
public FailoverLoadBalancerDefinition() {
}
@Override
protected LoadBalancer createLoadBalancer(RouteContext routeContext) {
FailOverLoadBalancer answer;
List> classes = new ArrayList<>();
if (!exceptionTypes.isEmpty()) {
classes.addAll(exceptionTypes);
} else if (!exceptions.isEmpty()) {
for (String name : exceptions) {
Class type = routeContext.getCamelContext().getClassResolver().resolveClass(name);
if (type == null) {
throw new IllegalArgumentException("Cannot find class: " + name + " in the classpath");
}
if (!ObjectHelper.isAssignableFrom(Throwable.class, type)) {
throw new IllegalArgumentException("Class is not an instance of Throwable: " + type);
}
classes.add(type);
}
}
if (classes.isEmpty()) {
answer = new FailOverLoadBalancer();
} else {
answer = new FailOverLoadBalancer(classes);
}
if (getMaximumFailoverAttempts() != null) {
answer.setMaximumFailoverAttempts(getMaximumFailoverAttempts());
}
if (roundRobin != null) {
answer.setRoundRobin(roundRobin);
}
if (sticky != null) {
answer.setSticky(sticky);
}
return answer;
}
public List getExceptions() {
return exceptions;
}
/**
* A list of class names for specific exceptions to monitor.
* If no exceptions is configured then all exceptions is monitored
*/
public void setExceptions(List exceptions) {
this.exceptions = exceptions;
}
public List> getExceptionTypes() {
return exceptionTypes;
}
/**
* A list of specific exceptions to monitor.
* If no exceptions is configured then all exceptions is monitored
*/
public void setExceptionTypes(List> exceptionTypes) {
this.exceptionTypes = exceptionTypes;
}
public Boolean getRoundRobin() {
return roundRobin;
}
/**
* Whether or not the failover load balancer should operate in round robin mode or not.
* If not, then it will always start from the first endpoint when a new message is to be processed.
* In other words it restart from the top for every message.
* If round robin is enabled, then it keeps state and will continue with the next endpoint in a round robin fashion.
*
* You can also enable sticky mode together with round robin, if so then it will pick the last known good endpoint
* to use when starting the load balancing (instead of using the next when starting).
*/
public void setRoundRobin(Boolean roundRobin) {
this.roundRobin = roundRobin;
}
public Boolean getSticky() {
return sticky;
}
/**
* Whether or not the failover load balancer should operate in sticky mode or not.
* If not, then it will always start from the first endpoint when a new message is to be processed.
* In other words it restart from the top for every message.
* If sticky is enabled, then it keeps state and will continue with the last known good endpoint.
*
* You can also enable sticky mode together with round robin, if so then it will pick the last known good endpoint
* to use when starting the load balancing (instead of using the next when starting).
*/
public void setSticky(Boolean sticky) {
this.sticky = sticky;
}
public Integer getMaximumFailoverAttempts() {
return maximumFailoverAttempts;
}
/**
* A value to indicate after X failover attempts we should exhaust (give up).
* Use -1 to indicate never give up and continuously try to failover. Use 0 to never failover.
* And use e.g. 3 to failover at most 3 times before giving up.
* his option can be used whether or not roundRobin is enabled or not.
*/
public void setMaximumFailoverAttempts(Integer maximumFailoverAttempts) {
this.maximumFailoverAttempts = maximumFailoverAttempts;
}
@Override
public String toString() {
return "FailoverLoadBalancer";
}
}