001    /**
002     * Licensed to the Apache Software Foundation (ASF) under one or more
003     * contributor license agreements.  See the NOTICE file distributed with
004     * this work for additional information regarding copyright ownership.
005     * The ASF licenses this file to You under the Apache License, Version 2.0
006     * (the "License"); you may not use this file except in compliance with
007     * the License.  You may obtain a copy of the License at
008     *
009     *      http://www.apache.org/licenses/LICENSE-2.0
010     *
011     * Unless required by applicable law or agreed to in writing, software
012     * distributed under the License is distributed on an "AS IS" BASIS,
013     * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
014     * See the License for the specific language governing permissions and
015     * limitations under the License.
016     */
017    package org.apache.camel.model;
018    
019    import java.util.ArrayList;
020    import java.util.Collection;
021    import java.util.List;
022    
023    import javax.xml.bind.annotation.XmlAccessType;
024    import javax.xml.bind.annotation.XmlAccessorType;
025    import javax.xml.bind.annotation.XmlAttribute;
026    import javax.xml.bind.annotation.XmlElement;
027    import javax.xml.bind.annotation.XmlElementRef;
028    import javax.xml.bind.annotation.XmlElements;
029    import javax.xml.bind.annotation.XmlRootElement;
030    
031    import org.apache.camel.Expression;
032    import org.apache.camel.Processor;
033    import org.apache.camel.model.loadbalancer.FailOverLoadBalanceStrategy;
034    import org.apache.camel.model.loadbalancer.LoadBalancerDefinition;
035    import org.apache.camel.model.loadbalancer.RandomLoadBalanceStrategy;
036    import org.apache.camel.model.loadbalancer.RoundRobinLoadBalanceStrategy;
037    import org.apache.camel.model.loadbalancer.StickyLoadBalanceStrategy;
038    import org.apache.camel.model.loadbalancer.TopicLoadBalanceStrategy;
039    import org.apache.camel.processor.SendProcessor;
040    import org.apache.camel.processor.loadbalancer.FailOverLoadBalancer;
041    import org.apache.camel.processor.loadbalancer.LoadBalancer;
042    import org.apache.camel.processor.loadbalancer.RandomLoadBalancer;
043    import org.apache.camel.processor.loadbalancer.RoundRobinLoadBalancer;
044    import org.apache.camel.processor.loadbalancer.StickyLoadBalancer;
045    import org.apache.camel.processor.loadbalancer.TopicLoadBalancer;
046    import org.apache.camel.spi.RouteContext;
047    import org.apache.camel.util.CollectionStringBuffer;
048    
049    /**
050     * Represents an XML <loadBalance/> element
051     */
052    @XmlRootElement(name = "loadBalance")
053    @XmlAccessorType(XmlAccessType.FIELD)
054    public class LoadBalanceDefinition extends ProcessorDefinition<LoadBalanceDefinition> {
055        @XmlAttribute(required = false)
056        private String ref;
057    
058        @XmlElements({
059            @XmlElement(required = false, name = "failOver", type = FailOverLoadBalanceStrategy.class),
060            @XmlElement(required = false, name = "roundRobin", type = RoundRobinLoadBalanceStrategy.class),
061            @XmlElement(required = false, name = "random", type = RandomLoadBalanceStrategy.class),
062            @XmlElement(required = false, name = "sticky", type = StickyLoadBalanceStrategy.class),
063            @XmlElement(required = false, name = "topic", type = TopicLoadBalanceStrategy.class)}
064            )
065        private LoadBalancerDefinition loadBalancerType;
066    
067        @XmlElementRef
068        private List<ProcessorDefinition> outputs = new ArrayList<ProcessorDefinition>();
069    
070        public LoadBalanceDefinition() {
071        }
072    
073        @Override
074        public String getShortName() {
075            return "loadbalance";
076        }
077    
078        public List<ProcessorDefinition> getOutputs() {
079            return outputs;
080        }
081    
082        public void setOutputs(List<ProcessorDefinition> outputs) {
083            this.outputs = outputs;
084            if (outputs != null) {
085                for (ProcessorDefinition output : outputs) {
086                    configureChild(output);
087                }
088            }
089        }
090    
091    
092        @Override
093        protected void configureChild(ProcessorDefinition output) {
094            super.configureChild(output);
095            if (isInheritErrorHandler()) {
096                output.setErrorHandlerBuilder(getErrorHandlerBuilder());
097            }
098        }
099    
100        public String getRef() {
101            return ref;
102        }
103    
104        public void setRef(String ref) {
105            this.ref = ref;
106        }
107    
108        public LoadBalancerDefinition getLoadBalancerType() {
109            return loadBalancerType;
110        }
111    
112        public void setLoadBalancerType(LoadBalancerDefinition loadbalancer) {
113            loadBalancerType = loadbalancer;
114        }
115    
116        protected Processor createOutputsProcessor(RouteContext routeContext, Collection<ProcessorDefinition> outputs)
117            throws Exception {
118            LoadBalancer loadBalancer = LoadBalancerDefinition.getLoadBalancer(routeContext, loadBalancerType, ref);
119            for (ProcessorDefinition processorType : outputs) {
120                // The outputs should be the SendProcessor
121                SendProcessor processor = (SendProcessor) processorType.createProcessor(routeContext);
122                loadBalancer.addProcessor(processor);
123            }
124            return loadBalancer;
125        }
126        
127        @Override
128        public Processor createProcessor(RouteContext routeContext) throws Exception {
129            LoadBalancer loadBalancer = LoadBalancerDefinition.getLoadBalancer(routeContext, loadBalancerType, ref);
130            for (ProcessorDefinition processorType : getOutputs()) {            
131                Processor processor = processorType.createProcessor(routeContext);
132                processor = processorType.wrapProcessorInInterceptors(routeContext, processor);
133                loadBalancer.addProcessor(processor);
134            }
135    
136            return loadBalancer;
137        }
138        
139        // Fluent API
140        // -------------------------------------------------------------------------
141        /**
142         * Sets the load balancer to use
143         *
144         * @param loadBalancer  the load balancer
145         * @return the builder
146         */
147        public LoadBalanceDefinition setLoadBalancer(LoadBalancer loadBalancer) {
148            loadBalancerType = new LoadBalancerDefinition(loadBalancer);
149            return this;
150        }
151        
152        /**
153         * Uses fail over load balancer
154         * 
155         * @return the builder
156         */
157        public LoadBalanceDefinition failOver() {
158            loadBalancerType = new LoadBalancerDefinition(new FailOverLoadBalancer());
159            return this;
160        }
161        
162        /**
163         * Uses fail over load balancer
164         * 
165         * @param throwable exception Class which we want to catch
166         * @return the builder
167         */
168        public LoadBalanceDefinition failOver(Class throwable) {
169            loadBalancerType = new LoadBalancerDefinition(new FailOverLoadBalancer(throwable));
170            return this;
171        }
172    
173        /**
174         * Uses round robin load balancer
175         *
176         * @return the builder
177         */
178        public LoadBalanceDefinition roundRobin() {
179            loadBalancerType = new LoadBalancerDefinition(new RoundRobinLoadBalancer());
180            return this;
181        }
182    
183        /**
184         * Uses random load balancer
185         * @return the builder
186         */
187        public LoadBalanceDefinition random() {
188            loadBalancerType = new LoadBalancerDefinition(new RandomLoadBalancer());
189            return this;
190        }
191    
192        /**
193         * Uses sticky load balancer
194         *
195         * @param correlationExpression  the expression for correlation
196         * @return  the builder
197         */
198        public LoadBalanceDefinition sticky(Expression correlationExpression) {
199            loadBalancerType = new LoadBalancerDefinition(new StickyLoadBalancer(correlationExpression));
200            return this;
201        }
202    
203        /**
204         * Uses topic load balancer
205         * 
206         * @return the builder
207         */
208        public LoadBalanceDefinition topic() {
209            loadBalancerType = new LoadBalancerDefinition(new TopicLoadBalancer());
210            return this;
211        }
212    
213        @Override
214        public String getLabel() {
215            CollectionStringBuffer buffer = new CollectionStringBuffer();
216            List<ProcessorDefinition> list = getOutputs();
217            for (ProcessorDefinition processorType : list) {
218                buffer.append(processorType.getLabel());
219            }
220            return buffer.toString();
221        }
222    
223        @Override
224        public String toString() {
225            if (loadBalancerType != null) {
226                return "LoadBalanceType[" + loadBalancerType + ", " + getOutputs() + "]";
227            } else {
228                return "LoadBalanceType[ref: " + ref + ", " + getOutputs() + "]";
229            }
230        }
231    
232    }