archive/net.sourceforge.phpeclipse.css.ui/src/net/sourceforge/phpeclipse/css/ui/internal/editor/CommentAction.java

   1 /*
   2  * Copyright (c) 2003-2004 Christopher Lenz and others.
   3  * All rights reserved. This program and the accompanying materials
   4  * are made available under the terms of the Common Public License v1.0
   5  * which accompanies this distribution, and is available at
   6  * http://www.eclipse.org/legal/cpl-v10.html
   7  *
   8  * Contributors:
   9  *     Christopher Lenz - initial API and implementation
  10  *
  11  * $Id: CommentAction.java,v 1.1 2004-09-02 18:11:50 jsurfer Exp $
  12  */
  13
  14 package net.sourceforge.phpeclipse.css.ui.internal.editor;
  15
  16 import java.util.ResourceBundle;
  17
  18 import org.eclipse.jface.text.BadLocationException;
  19 import org.eclipse.jface.text.IDocument;
  20 import org.eclipse.jface.text.IRewriteTarget;
  21 import org.eclipse.jface.text.ITextSelection;
  22 import org.eclipse.jface.viewers.ISelection;
  23 import org.eclipse.jface.viewers.ISelectionProvider;
  24 import org.eclipse.ui.IEditorInput;
  25 import org.eclipse.ui.texteditor.IDocumentProvider;
  26 import org.eclipse.ui.texteditor.ITextEditor;
  27 import org.eclipse.ui.texteditor.ITextEditorExtension2;
  28 import org.eclipse.ui.texteditor.TextEditorAction;
  29
  30 /**
  31  * (Heavily inspired by the AddBlockComment class in JDT-UI)
  32  */
  33 public class CommentAction extends TextEditorAction {
  34
  35         // Constructors ------------------------------------------------------------
  36
  37         /**
  38          * Constructor.
  39          *
  40          * @param bundle the resource bundle
  41          * @param prefix a prefix to be prepended to the various resource keys
  42          *        (described in <code>ResourceAction</code> constructor), or
  43          *        <code>null</code> if none
  44          * @param editor the text editor
  45          */
  46         public CommentAction(ResourceBundle bundle, String prefix,
  47                 ITextEditor editor) {
  48                 super(bundle, prefix, editor);
  49         }
  50
  51         // TextEditorAction Implementation -----------------------------------------
  52
  53         /**
  54          * @see org.eclipse.jface.action.Action#run()
  55          */
  56         public void run() {
  57                 if (!isEnabled()) {
  58                         return;
  59                 }
  60                 ITextEditor editor = getTextEditor();
  61                 if ((editor == null) || !ensureEditable(editor)) {
  62                         return;
  63                 }
  64                 ITextSelection selection = getCurrentSelection();
  65                 if (!validSelection(selection)) {
  66                         return;
  67                 }
  68                 IDocumentProvider docProvider = editor.getDocumentProvider();
  69                 IEditorInput input = editor.getEditorInput();
  70                 if (docProvider == null || input == null) {
  71                         return;
  72                 }
  73                 IDocument document = docProvider.getDocument(input);
  74                 if (document == null) {
  75                         return;
  76                 }
  77                 IRewriteTarget target = (IRewriteTarget)
  78                         editor.getAdapter(IRewriteTarget.class);
  79                 if (target != null) {
  80                         target.beginCompoundChange();
  81                 }
  82                 try {
  83                         int offset = selection.getOffset();
  84                         String start = "/*"; //$NON-NLS-1$
  85                         document.replace(offset, 0, start);
  86                         document.replace(offset + selection.getLength() + start.length(), 0,
  87                                 "*/"); //$NON-NLS-1$
  88                 } catch (BadLocationException e) {
  89                         // ignore
  90                 } finally {
  91                         if (target != null) {
  92                                 target.endCompoundChange();
  93                         }
  94                 }
  95         }
  96
  97         /**
  98          * @see org.eclipse.ui.texteditor.TextEditorAction#update()
  99          */
 100         public void update() {
 101                 super.update();
 102                 if (isEnabled()) {
 103                         if (!validSelection(getCurrentSelection())) {
 104                                 setEnabled(false);
 105                         }
 106                 }
 107         }
 108
 109         // Private Methods ---------------------------------------------------------
 110
 111         /**
 112          * Ensures that the editor is modifyable. If the editor is an instance of
 113          * <code>ITextEditorExtension2</code>, its
 114          * <code>validateEditorInputState</code> method is called, otherwise, the
 115          * result of <code>isEditable</code> is returned.
 116          *
 117          * @param editor the editor to be checked
 118          * @return <code>true</code> if the editor is editable, <code>false</code>
 119          *         otherwise
 120          */
 121         private boolean ensureEditable(ITextEditor editor) {
 122                 if (editor instanceof ITextEditorExtension2) {
 123                         ITextEditorExtension2 extension = (ITextEditorExtension2) editor;
 124                         return extension.validateEditorInputState();
 125                 }
 126                 return editor.isEditable();
 127         }
 128
 129         /**
 130          * Returns the editor's selection, or <code>null</code> if no selection can
 131          * be obtained or the editor is <code>null</code>.
 132          *
 133          * @return the selection of the action's editor, or <code>null</code>
 134          */
 135         private ITextSelection getCurrentSelection() {
 136                 ITextEditor editor = getTextEditor();
 137                 if (editor != null) {
 138                         ISelectionProvider provider = editor.getSelectionProvider();
 139                         if (provider != null) {
 140                                 ISelection selection = provider.getSelection();
 141                                 if (selection instanceof ITextSelection) {
 142                                         return (ITextSelection) selection;
 143                                 }
 144                         }
 145                 }
 146                 return null;
 147         }
 148
 149         /**
 150          * Checks whether <code>selection</code> is valid, i.e. neither
 151          * <code>null</code> or empty.
 152          *
 153          * @param selection the selection to check
 154          * @return <code>true</code> if the selection is valid, <code>false</code>
 155          *         otherwise
 156          */
 157         private boolean validSelection(ITextSelection selection) {
 158                 if (selection != null) {
 159                         return (!selection.isEmpty() && (selection.getLength() > 0));
 160                 }
 161                 return false;
 162         }
 163
 164 }