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Java > Open Source Codes > org > eclipse > jdt > internal > core > JavaCorePreferenceModifyListener


1 /*******************************************************************************
2  * Copyright (c) 2000, 2005 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.jdt.internal.core;
12
13 import org.eclipse.core.runtime.preferences.IEclipsePreferences;
14 import org.eclipse.core.runtime.preferences.InstanceScope;
15 import org.eclipse.core.runtime.preferences.PreferenceModifyListener;
16 import org.eclipse.jdt.core.*;
17 import org.osgi.service.prefs.BackingStoreException;
18 import org.osgi.service.prefs.Preferences;
19
20 public class JavaCorePreferenceModifyListener extends PreferenceModifyListener {
21     
22     static int PREFIX_LENGTH = JavaModelManager.CP_CONTAINER_PREFERENCES_PREFIX.length();
23     JavaModel javaModel = JavaModelManager.getJavaModelManager().getJavaModel();
24
25     /* (non-Javadoc)
26      * @see org.eclipse.core.runtime.preferences.PreferenceModifyListener#preApply(org.eclipse.core.runtime.preferences.IEclipsePreferences)
27      */
28     public IEclipsePreferences preApply(IEclipsePreferences node) {
29         Preferences instance = node.node(InstanceScope.SCOPE);
30         cleanJavaCore(instance.node(JavaCore.PLUGIN_ID));
31         return super.preApply(node);
32     }
33     
34     /**
35      * Clean imported preferences from obsolete keys.
36      *
37      * @param preferences JavaCore preferences.
38      */
39     void cleanJavaCore(Preferences preferences) {
40         try {
41             String JavaDoc[] keys = preferences.keys();
42             for (int k = 0, kl= keys.length; k<kl; k++) {
43                 String JavaDoc key = keys[k];
44                 if (key.startsWith(JavaModelManager.CP_CONTAINER_PREFERENCES_PREFIX) && !isJavaProjectAccessible(key)) {
45                     preferences.remove(key);
46                 }
47             }
48         } catch (BackingStoreException e) {
49             // do nothing
50 }
51     }
52
53     /**
54      * Returns whether a java project referenced in property key
55      * is still longer accessible or not.
56      *
57      * @param propertyName
58      * @return true if a project is referenced in given key and this project
59      * is still accessible, false otherwise.
60      */
61     boolean isJavaProjectAccessible(String JavaDoc propertyName) {
62         int index = propertyName.indexOf('|', PREFIX_LENGTH);
63         if (index > 0) {
64             final String JavaDoc projectName = propertyName.substring(PREFIX_LENGTH, index).trim();
65             JavaProject project = (JavaProject) javaModel.getJavaProject(projectName);
66             if (project.getProject().isAccessible()) {
67                 return true;
68             }
69         }
70         return false;
71     }
72
73 }
74
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