ObjectFilterTest


1   /*******************************************************************************
2    * Copyright (c) 2000, 2006 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  package org.eclipse.ui.internal;
12  
13  import java.util.HashMap  ;
14  import java.util.Iterator  ;
15  
16  import org.eclipse.core.runtime.IConfigurationElement;
17  import org.eclipse.ui.IActionFilter;
18  import org.eclipse.ui.internal.util.Util;
19  
20  /**
21   * An ObjectFilterTest is used to read an object filter from XML,
22   * and evaluate the results for a given object.
23   */
24  public class ObjectFilterTest {
25      private HashMap   filterElements;
26  
27      /**
28       * Create a new object filter. 
29       */
30      public ObjectFilterTest() {
31          // do nothing
32      }
33  
34      /**
35       * Add a filter element to the test.  This element must contain
36       * a name value filter pair, as defined by the 
37       * <code>org.eclipse.ui.actionFilters</code> extension point.
38       */
39      public boolean addFilterElement(IConfigurationElement element) {
40          String   name = element.getAttribute("name");//$NON-NLS-1$
41          if (name == null) {
42              return false;
43          }
44  
45          // Get positive property.
46          String   value = element.getAttribute("value");//$NON-NLS-1$
47          if (value == null) {
48              return false;
49          }
50          if (filterElements == null) {
51              filterElements = new HashMap  ();
52          }
53          filterElements.put(name, value);
54          return true;
55      }
56  
57      /**
58       * Returns whether the object filter correctly matches a
59       * given object.  The results will be <code>true</code> if there is
60       * a filter match.  
61       * <p>
62       * If <code>adaptable is true</code>, the result will also be
63       * <code>rue</code> if the object is a wrapper for a resource, and
64       * the resource produces a filter match.
65       * </p>
66       * 
67       * @param object the object to examine
68       * @returns <code>true</code> if there is a filter match.  
69       */
70      public boolean matches(Object   object, boolean adaptable) {
71          // Optimize it.
72          if (filterElements == null) {
73              return true;
74          }
75  
76          // Try out the object.
77          if (this.preciselyMatches(object)) {
78              return true;
79          }
80          return false;
81      }
82  
83      /**
84       * Returns whether the object filter correctly matches a given object.
85       */
86      private boolean preciselyMatches(Object   object) {
87          // Get the action filter.
88          IActionFilter filter = (IActionFilter)Util.getAdapter(object, IActionFilter.class);
89          if (filter == null) {
90              return false;
91          }
92  
93          // Run the action filter.
94          Iterator   iter = filterElements.keySet().iterator();
95          while (iter.hasNext()) {
96              String   name = (String  ) iter.next();
97              String   value = (String  ) filterElements.get(name);
98              if (!filter.testAttribute(object, name, value)) {
99                  return false;
100             }
101         }
102         return true;
103     }
104 }
105 
106
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