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Java > Open Source Codes > org > lateralnz > messaging > AbstractMessageHandler


1 /* ====================================================================
2  * The LateralNZ Software License, Version 1.0
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55 package org.lateralnz.messaging;
56
57 import java.io.Serializable JavaDoc;
58 import java.net.InetAddress JavaDoc;
59 import java.util.HashMap JavaDoc;
60 import java.util.Iterator JavaDoc;
61 import java.util.LinkedList JavaDoc;
62 import java.util.List JavaDoc;
63 import java.util.Map JavaDoc;
64
65 import org.apache.log4j.Logger;
66
67 import org.lateralnz.common.util.Constants;
68 import org.lateralnz.common.util.StringUtils;
69
70 /**
71  * an abstract message handler that implements the supporting regex methods
72  *
73  * @author J R Briggs
74  */
75 public abstract class AbstractMessageHandler implements MessageHandler, Constants, Serializable JavaDoc {
76   private static final Logger log = Logger.getLogger(AbstractMessageHandler.class.getName());
77   
78   protected Map JavaDoc listeners = new HashMap JavaDoc(); // a map of listeners (who want to receive events)
79
80   protected InetAddress JavaDoc addr = null;
81   protected int port;
82   private String JavaDoc allowedRegex = null;
83   private String JavaDoc disallowedRegex = null;
84   private int allowedPriority = 1;
85   private int disallowedPriority = 0;
86   private boolean allowed = true;
87
88   public synchronized void addListener(String JavaDoc group, MessageListener listener) {
89     List JavaDoc l = (List JavaDoc)listeners.get(group);
90     if (l == null) {
91       l = new LinkedList JavaDoc();
92       listeners.put(group, l);
93     }
94     l.add(listener);
95   }
96
97   public void notifyListeners(final Message msg) {
98     // if there are listeners registered for the group,
99 // send the event to them
100 if (listeners.containsKey(msg.getGroup())) {
101       Thread JavaDoc t = new Thread JavaDoc() {
102         public void run() {
103           List JavaDoc l = (List JavaDoc)listeners.get(msg.getGroup());
104           Iterator JavaDoc iter = l.iterator();
105           while (iter.hasNext()) {
106             MessageListener list = (MessageListener)iter.next();
107             list.handle(msg);
108           }
109         }
110       };
111       t.start();
112     }
113   }
114   
115  /**
116   * the inet address this handler is running against
117   */
118   public void setAddress(InetAddress JavaDoc addr, int port) {
119     this.addr = addr;
120     this.port = port;
121   }
122     
123   public void setAllowedGroupRegex(String JavaDoc regex, int priority) {
124     this.allowedRegex = regex;
125     this.allowedPriority = priority;
126     
127     if (this.allowedPriority > this.disallowedPriority) {
128       allowed = true;
129     }
130   }
131   
132   public void setDisallowedGroupRegex(String JavaDoc regex, int priority) {
133     this.disallowedRegex = regex;
134     this.disallowedPriority = priority;
135     
136     if (this.disallowedPriority > this.allowedPriority) {
137       allowed = false;
138     }
139   }
140
141   public boolean willTransmit(String JavaDoc group) {
142     // if allowed has a higher priority
143 if (allowed && allowedRegex != null && StringUtils.matches(group, allowedRegex)) {
144       return true;
145     }
146     // disallowed must have a higher priority, so that is checked
147 // first
148 else if (disallowedRegex != null && StringUtils.matches(group, disallowedRegex)) {
149       return false;
150     }
151     else {
152       // for everything else return true
153 return true;
154     }
155   }
156 }
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