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1   /*** 
2    * 
3    * Copyright 2004 Protique Ltd
4    * 
5    * Licensed under the Apache License, Version 2.0 (the "License"); 
6    * you may not use this file except in compliance with the License. 
7    * You may obtain a copy of the License at 
8    * 
9    * http://www.apache.org/licenses/LICENSE-2.0
10   * 
11   * Unless required by applicable law or agreed to in writing, software
12   * distributed under the License is distributed on an "AS IS" BASIS, 
13   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 
14   * See the License for the specific language governing permissions and 
15   * limitations under the License. 
16   * 
17   **/
18  
19  package org.codehaus.activecluster.election.impl;
20  
21  import org.codehaus.activecluster.Cluster;
22  import org.codehaus.activecluster.Node;
23  import org.codehaus.activecluster.election.ElectionStrategy;
24  
25  import javax.jms.JMSException;
26  import java.util.Iterator;
27  import java.util.Map;
28  
29  /***
30   * <p><code>BullyElectionStrategy</code> Use a simple bully algorithm to elect a coordinator.
31   * the member with the lowest lexicographical name is choosen</p>
32   *
33   * @version $Revision: 1.2 $
34   */
35  public class BullyElectionStrategy implements ElectionStrategy {
36  
37      /***
38       * Elect a coordinator.
39       *
40       * @param cluster
41       * @return the elected Node
42       * @throws JMSException
43       */
44      public Node doElection(Cluster cluster) throws JMSException {
45          Node elect = cluster.getLocalNode();
46  
47          Map nodes = cluster.getNodes();
48          for (Iterator i = nodes.values().iterator(); i.hasNext();) {
49              Node node = (Node) i.next();
50              if (elect.getName().compareTo(node.getName()) < 0) {
51                  elect = node;
52              }
53          }
54  
55          return elect;
56      }
57  
58  }