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Java > Open Source Codes > org > eclipse > jdt > internal > ui > text > folding > JavaFoldingStructureProviderDescriptor


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.jdt.internal.ui.text.folding;
12
13 import org.eclipse.core.runtime.Assert;
14 import org.eclipse.core.runtime.CoreException;
15 import org.eclipse.core.runtime.IConfigurationElement;
16
17
18 import org.eclipse.jdt.ui.text.folding.IJavaFoldingPreferenceBlock;
19 import org.eclipse.jdt.ui.text.folding.IJavaFoldingStructureProvider;
20
21 /**
22  * Describes a contribution to the folding provider extension point.
23  *
24  * @since 3.0
25  */
26 public final class JavaFoldingStructureProviderDescriptor {
27
28     /* extension point attribute names */
29
30     private static final String JavaDoc PREFERENCES_CLASS= "preferencesClass"; //$NON-NLS-1$
31 private static final String JavaDoc CLASS= "class"; //$NON-NLS-1$
32 private static final String JavaDoc NAME= "name"; //$NON-NLS-1$
33 private static final String JavaDoc ID= "id"; //$NON-NLS-1$
34
35     /** The identifier of the extension. */
36     private String JavaDoc fId;
37     /** The name of the extension. */
38     private String JavaDoc fName;
39     /** The class name of the provided <code>IJavaFoldingStructureProvider</code>. */
40     private String JavaDoc fClass;
41     /**
42      * <code>true</code> if the extension specifies a custom
43      * <code>IJavaFoldingPreferenceBlock</code>.
44      */
45     private boolean fHasPreferences;
46     /** The configuration element of this extension. */
47     private IConfigurationElement fElement;
48
49     /**
50      * Creates a new descriptor.
51      *
52      * @param element the configuration element to read
53      */
54     JavaFoldingStructureProviderDescriptor(IConfigurationElement element) {
55         fElement= element;
56         fId= element.getAttribute(ID);
57         Assert.isLegal(fId != null);
58
59         fName= element.getAttribute(NAME);
60         if (fName == null)
61             fName= fId;
62
63         fClass= element.getAttribute(CLASS);
64         Assert.isLegal(fClass != null);
65
66         if (element.getAttribute(PREFERENCES_CLASS) == null)
67             fHasPreferences= false;
68         else
69             fHasPreferences= true;
70     }
71
72     /**
73      * Creates a folding provider as described in the extension's xml.
74      *
75      * @return a new instance of the folding provider described by this
76      * descriptor
77      * @throws CoreException if creation fails
78      */
79     public IJavaFoldingStructureProvider createProvider() throws CoreException {
80         IJavaFoldingStructureProvider prov= (IJavaFoldingStructureProvider) fElement.createExecutableExtension(CLASS);
81         return prov;
82     }
83
84     /**
85      * Creates a preferences object as described in the extension's xml.
86      *
87      * @return a new instance of the reference provider described by this
88      * descriptor
89      * @throws CoreException if creation fails
90      */
91     public IJavaFoldingPreferenceBlock createPreferences() throws CoreException {
92         if (fHasPreferences) {
93             IJavaFoldingPreferenceBlock prefs= (IJavaFoldingPreferenceBlock) fElement.createExecutableExtension(PREFERENCES_CLASS);
94             return prefs;
95         } else {
96             return new EmptyJavaFoldingPreferenceBlock();
97         }
98     }
99
100     /**
101      * Returns the identifier of the described extension.
102      *
103      * @return Returns the id
104      */
105     public String JavaDoc getId() {
106         return fId;
107     }
108
109     /**
110      * Returns the name of the described extension.
111      *
112      * @return Returns the name
113      */
114     public String JavaDoc getName() {
115         return fName;
116     }
117 }
118
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