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.reifier.loadbalancer;
018
019import java.util.HashMap;
020import java.util.Map;
021import java.util.function.Function;
022
023import org.apache.camel.model.LoadBalancerDefinition;
024import org.apache.camel.model.loadbalancer.CustomLoadBalancerDefinition;
025import org.apache.camel.model.loadbalancer.FailoverLoadBalancerDefinition;
026import org.apache.camel.model.loadbalancer.RandomLoadBalancerDefinition;
027import org.apache.camel.model.loadbalancer.RoundRobinLoadBalancerDefinition;
028import org.apache.camel.model.loadbalancer.StickyLoadBalancerDefinition;
029import org.apache.camel.model.loadbalancer.TopicLoadBalancerDefinition;
030import org.apache.camel.model.loadbalancer.WeightedLoadBalancerDefinition;
031import org.apache.camel.processor.loadbalancer.LoadBalancer;
032import org.apache.camel.spi.RouteContext;
033import org.apache.camel.util.StringHelper;
034
035public class LoadBalancerReifier<T extends LoadBalancerDefinition> {
036
037    private static final Map<Class<?>, Function<LoadBalancerDefinition, LoadBalancerReifier<? extends LoadBalancerDefinition>>> LOAD_BALANCERS;
038    static {
039        Map<Class<?>, Function<LoadBalancerDefinition, LoadBalancerReifier<? extends LoadBalancerDefinition>>> map = new HashMap<>();
040        map.put(LoadBalancerDefinition.class, LoadBalancerReifier::new);
041        map.put(CustomLoadBalancerDefinition.class, CustomLoadBalancerReifier::new);
042        map.put(FailoverLoadBalancerDefinition.class, FailoverLoadBalancerReifier::new);
043        map.put(RandomLoadBalancerDefinition.class, RandomLoadBalancerReifier::new);
044        map.put(RoundRobinLoadBalancerDefinition.class, RoundRobinLoadBalancerReifier::new);
045        map.put(StickyLoadBalancerDefinition.class, StickyLoadBalancerReifier::new);
046        map.put(TopicLoadBalancerDefinition.class, TopicLoadBalancerReifier::new);
047        map.put(WeightedLoadBalancerDefinition.class, WeightedLoadBalancerReifier::new);
048        LOAD_BALANCERS = map;
049    }
050
051    protected final T definition;
052
053    public LoadBalancerReifier(T definition) {
054        this.definition = definition;
055    }
056
057    public static LoadBalancerReifier<? extends LoadBalancerDefinition> reifier(LoadBalancerDefinition definition) {
058        Function<LoadBalancerDefinition, LoadBalancerReifier<? extends LoadBalancerDefinition>> reifier = LOAD_BALANCERS.get(definition.getClass());
059        if (reifier != null) {
060            return reifier.apply(definition);
061        }
062        throw new IllegalStateException("Unsupported definition: " + definition);
063    }
064
065    /**
066     * Factory method to create the load balancer from the loadBalancerTypeName
067     */
068    public LoadBalancer createLoadBalancer(RouteContext routeContext) {
069        String loadBalancerTypeName = definition.getLoadBalancerTypeName();
070        StringHelper.notEmpty(loadBalancerTypeName, "loadBalancerTypeName", this);
071
072        LoadBalancer answer = null;
073        if (loadBalancerTypeName != null) {
074            Class<?> type = routeContext.getCamelContext().getClassResolver().resolveClass(loadBalancerTypeName, LoadBalancer.class);
075            if (type == null) {
076                throw new IllegalArgumentException("Cannot find class: " + loadBalancerTypeName + " in the classpath");
077            }
078            answer = (LoadBalancer)routeContext.getCamelContext().getInjector().newInstance(type, false);
079            definition.configureLoadBalancer(answer);
080        }
081
082        return answer;
083    }
084
085}