software/webapp/src/main/java/org/apache/brooklyn/entity/proxy/LoadBalancerClusterImpl.java

/*
 * Licensed to the Apache Software Foundation (ASF) under one
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 * 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,
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package org.apache.brooklyn.entity.proxy;

import java.util.Map;

import org.apache.brooklyn.api.entity.Entity;
import org.apache.brooklyn.api.entity.Group;
import org.apache.brooklyn.entity.group.DynamicClusterImpl;

/**
 * A cluster of load balancers, where configuring the cluster (through the LoadBalancer interface)
 * will configure all load balancers in the cluster.
 * 
 * Config keys (such as LoadBalancer.serverPool and LoadBalancer.urlMappings) are automatically
 * inherited by the children of the load balancer cluster. It is through that mechanism that
 * configuration changes on the cluster will be applied to all child load balancers (i.e. by
 * them all sharing the same serverPool and urlMappings etc).
 *  
 * @author aled
 */
public class LoadBalancerClusterImpl extends DynamicClusterImpl implements LoadBalancerCluster {

    // TODO I suspect there are races with reconfiguring the load-balancers while
    // the cluster is growing: there is no synchronization around the calls to reload
    // and the resize, so presumably there's a race where a newly added load-balancer 
    // could miss the most recent reload call?

    public LoadBalancerClusterImpl() {
        super();
    }

    /* NOTE The following methods come from {@link LoadBalancer} but are probably safe to ignore */
    
    @Override
    public void reload() {
        for (Entity member : getMembers()) {
            if (member instanceof LoadBalancer) {
                ((LoadBalancer)member).reload();
            }
        }
    }

    @Override
    public void update() {
        for (Entity member : getMembers()) {
            if (member instanceof LoadBalancer) {
                ((LoadBalancer)member).update();
            }
        }
    }

    @Override
    public void bind(Map<?,?> flags) {
        for (Entity member : getMembers()) {
            if (member instanceof LoadBalancer) {
                ((LoadBalancer)member).bind(flags);
            }
        }
    }
    
    @Override
    public void changeServerPool(String groupId) {
        Group newGroup = (Group) getManagementContext().getEntityManager().getEntity(groupId);
        if (newGroup == null) {
            throw new IllegalArgumentException("Group '"+groupId+"' not found");
        }
        
        for (Entity member : getMembers()) {
            if (member instanceof LoadBalancer) {
                ((LoadBalancer)member).changeServerPool(groupId);
            }
        }
    }
}