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Java > Open Source Codes > org > eclipse > jface > text > DefaultTextHover


1 /*******************************************************************************
2  * Copyright (c) 2005, 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.jface.text;
12
13 import java.util.Iterator JavaDoc;
14
15 import org.eclipse.core.runtime.Assert;
16
17 import org.eclipse.jface.text.source.Annotation;
18 import org.eclipse.jface.text.source.IAnnotationModel;
19 import org.eclipse.jface.text.source.ISourceViewer;
20 import org.eclipse.jface.text.source.ISourceViewerExtension2;
21
22 /**
23  * Standard implementation of {@link org.eclipse.jface.text.ITextHover}.
24  *
25  * @since 3.2
26  */
27 public class DefaultTextHover implements ITextHover {
28
29     /** This hover's source viewer */
30     private ISourceViewer fSourceViewer;
31
32     /**
33      * Creates a new annotation hover.
34      *
35      * @param sourceViewer this hover's annotation model
36      */
37     public DefaultTextHover(ISourceViewer sourceViewer) {
38         Assert.isNotNull(sourceViewer);
39         fSourceViewer= sourceViewer;
40     }
41     
42     /*
43      * @see org.eclipse.jface.text.ITextHover#getHoverInfo(org.eclipse.jface.text.ITextViewer, org.eclipse.jface.text.IRegion)
44      */
45     public String JavaDoc getHoverInfo(ITextViewer textViewer, IRegion hoverRegion) {
46         IAnnotationModel model= getAnnotationModel(fSourceViewer);
47         if (model == null)
48             return null;
49         
50         Iterator JavaDoc e= model.getAnnotationIterator();
51         while (e.hasNext()) {
52             Annotation a= (Annotation) e.next();
53             if (isIncluded(a)) {
54                 Position p= model.getPosition(a);
55                 if (p != null && p.overlapsWith(hoverRegion.getOffset(), hoverRegion.getLength())) {
56                     String JavaDoc msg= a.getText();
57                     if (msg != null && msg.trim().length() > 0)
58                         return msg;
59                 }
60             }
61         }
62         
63         return null;
64     }
65
66     /*
67      * @see org.eclipse.jface.text.ITextHover#getHoverRegion(org.eclipse.jface.text.ITextViewer, int)
68      */
69     public IRegion getHoverRegion(ITextViewer textViewer, int offset) {
70         return findWord(textViewer.getDocument(), offset);
71     }
72     
73     /**
74      * Tells whether the annotation should be included in
75      * the computation.
76      *
77      * @param annotation the annotation to test
78      * @return <code>true</code> if the annotation is included in the computation
79      */
80     protected boolean isIncluded(Annotation annotation) {
81         return true;
82     }
83     
84     private IAnnotationModel getAnnotationModel(ISourceViewer viewer) {
85         if (viewer instanceof ISourceViewerExtension2) {
86             ISourceViewerExtension2 extension= (ISourceViewerExtension2) viewer;
87             return extension.getVisualAnnotationModel();
88         }
89         return viewer.getAnnotationModel();
90     }
91     
92     private IRegion findWord(IDocument document, int offset) {
93         int start= -1;
94         int end= -1;
95
96         try {
97
98             int pos= offset;
99             char c;
100
101             while (pos >= 0) {
102                 c= document.getChar(pos);
103                 if (!Character.isUnicodeIdentifierPart(c))
104                     break;
105                 --pos;
106             }
107
108             start= pos;
109
110             pos= offset;
111             int length= document.getLength();
112
113             while (pos < length) {
114                 c= document.getChar(pos);
115                 if (!Character.isUnicodeIdentifierPart(c))
116                     break;
117                 ++pos;
118             }
119
120             end= pos;
121
122         } catch (BadLocationException x) {
123         }
124
125         if (start > -1 && end > -1) {
126             if (start == offset && end == offset)
127                 return new Region(offset, 0);
128             else if (start == offset)
129                 return new Region(start, end - start);
130             else
131                 return new Region(start + 1, end - start - 1);
132         }
133
134         return null;
135     }
136 }
137
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