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 */
017package org.apache.camel.model;
018
019import java.util.Map;
020
021import javax.xml.bind.annotation.XmlAccessType;
022import javax.xml.bind.annotation.XmlAccessorType;
023import javax.xml.bind.annotation.XmlAnyAttribute;
024import javax.xml.bind.annotation.XmlTransient;
025import javax.xml.bind.annotation.XmlType;
026import javax.xml.namespace.QName;
027
028import org.apache.camel.processor.loadbalancer.LoadBalancer;
029import org.apache.camel.spi.Metadata;
030import org.apache.camel.spi.RouteContext;
031import org.apache.camel.util.IntrospectionSupport;
032import org.apache.camel.util.StringHelper;
033
034/**
035 * Balances message processing among a number of nodes
036 */
037@Metadata(label = "eip,routing")
038@XmlType(name = "loadBalancer")
039@XmlAccessorType(XmlAccessType.FIELD)
040public class LoadBalancerDefinition extends IdentifiedType implements OtherAttributesAware {
041    @XmlTransient
042    private LoadBalancer loadBalancer;
043    @XmlTransient
044    private String loadBalancerTypeName;
045    // use xs:any to support optional property placeholders
046    @XmlAnyAttribute
047    private Map<QName, Object> otherAttributes;
048
049    public LoadBalancerDefinition() {
050    }
051
052    public LoadBalancerDefinition(LoadBalancer loadBalancer) {
053        this.loadBalancer = loadBalancer;
054    }
055
056    protected LoadBalancerDefinition(String loadBalancerTypeName) {
057        this.loadBalancerTypeName = loadBalancerTypeName;
058    }
059
060    /**
061     * Sets a named property on the data format instance using introspection
062     */
063    protected void setProperty(Object bean, String name, Object value) {
064        try {
065            IntrospectionSupport.setProperty(bean, name, value);
066        } catch (Exception e) {
067            throw new IllegalArgumentException("Failed to set property " + name + " on " + bean + ". Reason: " + e, e);
068        }
069    }
070
071    /**
072     * Maximum number of outputs, as some load balancers only support 1 processor
073     */
074    protected int getMaximumNumberOfOutputs() {
075        return Integer.MAX_VALUE;
076    }
077
078    /**
079     * Allows derived classes to customize the load balancer
080     */
081    protected void configureLoadBalancer(LoadBalancer loadBalancer) {
082    }
083
084    public LoadBalancer getLoadBalancer(RouteContext routeContext) {
085        return loadBalancer;
086    }
087
088    public void setLoadBalancer(LoadBalancer loadBalancer) {
089        this.loadBalancer = loadBalancer;
090    }
091
092    @Override
093    public Map<QName, Object> getOtherAttributes() {
094        return otherAttributes;
095    }
096
097    @Override
098    public void setOtherAttributes(Map<QName, Object> otherAttributes) {
099        this.otherAttributes = otherAttributes;
100    }
101
102    /**
103     * Factory method to create the load balancer from the loadBalancerTypeName
104     */
105    protected LoadBalancer createLoadBalancer(RouteContext routeContext) {
106        StringHelper.notEmpty(loadBalancerTypeName, "loadBalancerTypeName", this);
107
108        LoadBalancer answer = null;
109        if (loadBalancerTypeName != null) {
110            Class<?> type = routeContext.getCamelContext().getClassResolver().resolveClass(loadBalancerTypeName, LoadBalancer.class);
111            if (type == null) {
112                throw new IllegalArgumentException("Cannot find class: " + loadBalancerTypeName + " in the classpath");
113            }
114            answer = (LoadBalancer) routeContext.getCamelContext().getInjector().newInstance(type);
115            configureLoadBalancer(answer);
116        }
117
118        return answer;
119    }
120
121    @Override
122    public String toString() {
123        if (loadBalancer != null) {
124            return loadBalancer.toString();
125        } else {
126            return loadBalancerTypeName;
127        }
128    }
129}