Dispatcher


1   /*
2    * ====================================================================
3    * This software is subject to the terms of the Common Public License
4    * Agreement, available at the following URL:
5    *   http://www.opensource.org/licenses/cpl.html .
6    * Copyright (C) 2003-2004 TONBELLER AG.
7    * All Rights Reserved.
8    * You must accept the terms of that agreement to use this software.
9    * ====================================================================
10   *
11   * 
12   */
13  package com.tonbeller.wcf.controller;
14  
15  import java.util.List  ;
16  import java.util.Map  ;
17  
18  /**
19   * Fires events to listeners depending on parameters in the HttpServletRequest.
20   * <ul>
21   * <li>If a listener is registered with name <em>and</em> value, it receives the event
22   * if the request contains a paramter with that name and value.
23   * <li>If a listener is registered with name only, it receives the event if the request
24   * contains a parameter with that name and any value.
25   * <li>If a listener is registered with value only, it receives the event if the request
26   * contains a parameter with that value and any name.
27   * <li>If a listener is registered with no name and no value, it receives every request.
28   * </ul>
29   */
30  public interface Dispatcher extends RequestListener {
31  
32    /**
33     * Adds a listener. A listener can only be registered once.
34     * If its registered more than once, the last name/value
35     * pair will be used.
36     *
37     * @param name name of the request parameter or null
38     * @param value of the request parameter or null
39     * @param listener the listener to register
40     */
41    void addRequestListener(String   name, String   value, RequestListener listener);
42  
43    /**
44     * removes a listener.
45     * @param listener the listener to remove
46     */
47    void removeRequestListener(RequestListener listener);
48  
49    /**
50     * removes all listeners
51     */
52    void clear();
53  
54    /**
55     * fires an event to all matching RequestListeners
56     * @param context the current request
57     * @throws Exception the exception from listeners
58     */
59    void request(RequestContext context) throws Exception  ;
60  
61    /**
62     * returns the list of leaf RequestListeners that would be
63     * invoked for a request with the given parameters.
64     */
65    List   findMatchingListeners(Map   httpParams);
66    
67  }
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