StatusHandlerDescriptorsMap


1   /*******************************************************************************
2    * Copyright (c) 2007 IBM Corporation and others.
3    * All rights reserved. This program and the accompanying materials
4    * are made available under the terms of the Eclipse Public License v1.0
5    * which accompanies this distribution, and is available at
6    * http://www.eclipse.org/legal/epl-v10.html
7    *
8    * Contributors:
9    *     IBM Corporation - initial API and implementation
10   ******************************************************************************/
11  
12  package org.eclipse.ui.internal.statushandlers;
13  
14  import java.util.ArrayList  ;
15  import java.util.HashMap  ;
16  import java.util.List  ;
17  import java.util.Map  ;
18  
19  /**
20   * Helper class supporting the prefix based status handling policy.
21   * 
22   * @since 3.3
23   */
24  class StatusHandlerDescriptorsMap {
25  
26      private final String   ASTERISK = "*"; //$NON-NLS-1$
27  
28      private HashMap   map;
29  
30      /**
31       * Creates a new instance of the class
32       */
33      public StatusHandlerDescriptorsMap() {
34          map = new HashMap  ();
35      }
36  
37      /**
38       * Adds a new handler descriptor to the prefix tree
39       * 
40       * @param handlerDescriptor
41       *            the handler descriptor to add
42       */
43      public void addHandlerDescriptor(StatusHandlerDescriptor handlerDescriptor) {
44          add(this.map, handlerDescriptor.getPrefix(), handlerDescriptor);
45      }
46  
47      /*
48       * Recursively searches the tree for the best place for the handler
49       * descriptor
50       */
51      private void add(Map   map, String   prefix,
52              StatusHandlerDescriptor handlerDescriptor) {
53          if (prefix == null) {
54              if (map.get(ASTERISK) == null) {
55                  map.put(ASTERISK, new ArrayList  ());
56              }
57  
58              ((List  ) map.get(ASTERISK)).add(handlerDescriptor);
59          } else {
60              int delimIndex = prefix.indexOf("."); //$NON-NLS-1$
61  
62              String   pre = null;
63              String   post = null;
64  
65              if (delimIndex != -1) {
66                  pre = prefix.substring(0, delimIndex);
67  
68                  if (delimIndex < prefix.length() - 1) {
69                      post = prefix.substring(delimIndex + 1);
70                  }
71              } else {
72                  pre = prefix;
73              }
74  
75              if (map.get(pre) == null) {
76                  map.put(pre, new HashMap  ());
77              }
78  
79              add((Map  ) map.get(pre), post, handlerDescriptor);
80          }
81      }
82  
83      public void clear() {
84          map.clear();
85      }
86  
87      /**
88       * Returns status handler descriptors whose prefixes are the most specific
89       * for given pluginId.
90       * 
91       * @param pluginId
92       * @return handler descriptors list
93       */
94      public List   getHandlerDescriptors(String   pluginId) {
95          return get(pluginId, this.map);
96      }
97  
98      /*
99       * Recursively searches the prefix tree for the most specific handler
100      * descriptor for the given pluginId.
101      */
102     private List   get(String   pluginId, Map   map) {
103         if (pluginId == null) {
104             return getAsteriskList(map);
105         }
106 
107         int delimIndex = pluginId.indexOf("."); //$NON-NLS-1$
108 
109         String   pre = null;
110         String   post = null;
111 
112         if (delimIndex != -1) {
113             pre = pluginId.substring(0, delimIndex);
114 
115             if (delimIndex < pluginId.length() - 1) {
116                 post = pluginId.substring(delimIndex + 1);
117             }
118         } else {
119             pre = pluginId;
120         }
121 
122         if (map.get(pre) == null) {
123             return getAsteriskList(map);
124         }
125 
126         return get(post, (Map  ) map.get(pre));
127     }
128 
129     private List   getAsteriskList(Map   map) {
130         Object   list = map.get(ASTERISK);
131         if (list != null) {
132             return (List  ) list;
133         }
134 
135         return null;
136     }
137 }
138
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