net.sourceforge.phpeclipse/src/net/sourceforge/phpdt/internal/ui/actions/BlockCommentAction.java

   1 /*******************************************************************************
   2  * Copyright (c) 2000, 2004 IBM Corporation 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  *     IBM Corporation - initial API and implementation
  10  *******************************************************************************/
  11 package net.sourceforge.phpdt.internal.ui.actions;
  12
  13 import java.util.Iterator;
  14 import java.util.List;
  15 import java.util.ResourceBundle;
  16
  17 import org.eclipse.jface.text.Assert;
  18 import org.eclipse.jface.text.BadLocationException;
  19 import org.eclipse.jface.text.BadPartitioningException;
  20 import org.eclipse.jface.text.BadPositionCategoryException;
  21 import org.eclipse.jface.text.DefaultPositionUpdater;
  22 import org.eclipse.jface.text.DocumentEvent;
  23 import org.eclipse.jface.text.IDocument;
  24 import org.eclipse.jface.text.IDocumentExtension3;
  25 import org.eclipse.jface.text.IPositionUpdater;
  26 import org.eclipse.jface.text.IRewriteTarget;
  27 import org.eclipse.jface.text.ITextSelection;
  28 import org.eclipse.jface.text.Position;
  29 import org.eclipse.jface.viewers.ISelection;
  30 import org.eclipse.jface.viewers.ISelectionProvider;
  31 import org.eclipse.ui.IEditorInput;
  32 import org.eclipse.ui.texteditor.IDocumentProvider;
  33 import org.eclipse.ui.texteditor.ITextEditor;
  34 import org.eclipse.ui.texteditor.ITextEditorExtension2;
  35 import org.eclipse.ui.texteditor.TextEditorAction;
  36
  37
  38 /**
  39  * Common block comment code.
  40  *
  41  * @since 3.0
  42  */
  43 public abstract class BlockCommentAction extends TextEditorAction {
  44
  45         /**
  46          * Creates a new instance.
  47          * @param bundle
  48          * @param prefix
  49          * @param editor
  50          */
  51         public BlockCommentAction(ResourceBundle bundle, String prefix, ITextEditor editor) {
  52                 super(bundle, prefix, editor);
  53         }
  54
  55         /**
  56          * An edit is a kind of <code>DocumentEvent</code>, in this case an edit instruction, that is
  57          * affilitated with a <code>Position</code> on a document. The offset of the document event is
  58          * not stored statically, but taken from the affiliated <code>Position</code>, which gets
  59          * updated when other edits occurr.
  60          */
  61         static class Edit extends DocumentEvent {
  62
  63                 /**
  64                  * Factory for edits which manages the creation, installation and destruction of
  65                  * position categories, position updaters etc. on a certain document. Once a factory has
  66                  * been obtained, <code>Edit</code> objects can be obtained from it which will be linked to
  67                  * the document by positions of one position category.
  68                  * <p>Clients are required to call <code>release</code> once the <code>Edit</code>s are not
  69                  * used any more, so the positions can be discarded.</p>
  70                  */
  71                 public static class EditFactory {
  72
  73                         /** The position category basename for this edits. */
  74                         private static final String CATEGORY= "__positionalEditPositionCategory"; //$NON-NLS-1$
  75
  76                         /** The count of factories. */
  77                         private static int fgCount= 0;
  78
  79                         /** This factory's category. */
  80                         private final String fCategory;
  81                         private IDocument fDocument;
  82                         private IPositionUpdater fUpdater;
  83
  84                         /**
  85                          * Creates a new <code>EditFactory</code> with an unambiguous position category name.
  86                          * @param document the document that is being edited.
  87                          */
  88                         public EditFactory(IDocument document) {
  89                                 fCategory= CATEGORY + fgCount++;
  90                                 fDocument= document;
  91                         }
  92
  93                         /**
  94                          * Creates a new edition on the document of this factory.
  95                          *
  96                          * @param offset the offset of the edition at the point when is created.
  97                          * @param length the length of the edition (not updated via the position update mechanism)
  98                          * @param text the text to be replaced on the document
  99                          * @return an <code>Edit</code> reflecting the edition on the document
 100                          */
 101                         public Edit createEdit(int offset, int length, String text) throws BadLocationException {
 102
 103                                 if (!fDocument.containsPositionCategory(fCategory)) {
 104                                         fDocument.addPositionCategory(fCategory);
 105                                         fUpdater= new DefaultPositionUpdater(fCategory);
 106                                         fDocument.addPositionUpdater(fUpdater);
 107                                 }
 108
 109                                 Position position= new Position(offset);
 110                                 try {
 111                                         fDocument.addPosition(fCategory, position);
 112                                 } catch (BadPositionCategoryException e) {
 113                                         Assert.isTrue(false);
 114                                 }
 115                                 return new Edit(fDocument, length, text, position);
 116                         }
 117
 118                         /**
 119                          * Releases the position category on the document and uninstalls the position updater.
 120                          * <code>Edit</code>s managed by this factory are not updated after this call.
 121                          */
 122                         public void release() {
 123                                 if (fDocument != null && fDocument.containsPositionCategory(fCategory)) {
 124                                         fDocument.removePositionUpdater(fUpdater);
 125                                         try {
 126                                                 fDocument.removePositionCategory(fCategory);
 127                                         } catch (BadPositionCategoryException e) {
 128                                                 Assert.isTrue(false);
 129                                         }
 130                                         fDocument= null;
 131                                         fUpdater= null;
 132                                 }
 133                         }
 134                 }
 135
 136                 /** The position in the document where this edit be executed. */
 137                 private Position fPosition;
 138
 139                 /**
 140                  * Creates a new edition on <code>document</code>, taking its offset from <code>position</code>.
 141                  *
 142                  * @param document the document being edited
 143                  * @param length the length of the edition
 144                  * @param text the replacement text of the edition
 145                  * @param position the position keeping the edition's offset
 146                  */
 147                 protected Edit(IDocument document, int length, String text, Position position) {
 148                         super(document, 0, length, text);
 149                         fPosition= position;
 150                 }
 151
 152                 /*
 153                  * @see org.eclipse.jface.text.DocumentEvent#getOffset()
 154                  */
 155                 public int getOffset() {
 156                         return fPosition.getOffset();
 157                 }
 158
 159                 /**
 160                  * Executes the edition on document. The offset is taken from the position.
 161                  *
 162                  * @throws BadLocationException if the execution of the document fails.
 163                  */
 164                 public void perform() throws BadLocationException {
 165                         getDocument().replace(getOffset(), getLength(), getText());
 166                 }
 167
 168         }
 169
 170         public void run() {
 171                 if (!isEnabled())
 172                         return;
 173
 174                 ITextEditor editor= getTextEditor();
 175                 if (editor == null || !ensureEditable(editor))
 176                         return;
 177
 178                 ITextSelection selection= getCurrentSelection();
 179                 if (!isValidSelection(selection))
 180                         return;
 181
 182                 if (!validateEditorInputState())
 183                         return;
 184
 185                 IDocumentProvider docProvider= editor.getDocumentProvider();
 186                 IEditorInput input= editor.getEditorInput();
 187                 if (docProvider == null || input == null)
 188                         return;
 189
 190                 IDocument document= docProvider.getDocument(input);
 191                 if (document == null)
 192                         return;
 193
 194                 IDocumentExtension3 docExtension;
 195                 if (document instanceof IDocumentExtension3)
 196                         docExtension= (IDocumentExtension3) document;
 197                 else
 198                         return;
 199
 200                 IRewriteTarget target= (IRewriteTarget)editor.getAdapter(IRewriteTarget.class);
 201                 if (target != null) {
 202                         target.beginCompoundChange();
 203                 }
 204
 205                 Edit.EditFactory factory= new Edit.EditFactory(document);
 206
 207                 try {
 208                         runInternal(selection, docExtension, factory);
 209
 210                 } catch (BadLocationException e) {
 211                         // can happen on concurrent modification, deletion etc. of the document
 212                         // -> don't complain, just bail out
 213                 } catch (BadPartitioningException e) {
 214                         // should not happen
 215                         Assert.isTrue(false, "bad partitioning");  //$NON-NLS-1$
 216                 } finally {
 217                         factory.release();
 218
 219                         if (target != null) {
 220                                 target.endCompoundChange();
 221                         }
 222                 }
 223         }
 224
 225         /**
 226          * Calls <code>perform</code> on all <code>Edit</code>s in <code>edits</code>.
 227          *
 228          * @param edits a list of <code>Edit</code>s
 229          * @throws BadLocationException if an <code>Edit</code> threw such an exception.
 230          */
 231         protected void executeEdits(List edits) throws BadLocationException {
 232                 for (Iterator it= edits.iterator(); it.hasNext();) {
 233                         Edit edit= (Edit) it.next();
 234                         edit.perform();
 235                 }
 236         }
 237
 238         /**
 239          * Ensures that the editor is modifyable. If the editor is an instance of
 240          * <code>ITextEditorExtension2</code>, its <code>validateEditorInputState</code> method
 241          * is called, otherwise, the result of <code>isEditable</code> is returned.
 242          *
 243          * @param editor the editor to be checked
 244          * @return <code>true</code> if the editor is editable, <code>false</code> otherwise
 245          */
 246         protected boolean ensureEditable(ITextEditor editor) {
 247                 Assert.isNotNull(editor);
 248
 249                 if (editor instanceof ITextEditorExtension2) {
 250                         ITextEditorExtension2 ext= (ITextEditorExtension2) editor;
 251                         return ext.validateEditorInputState();
 252                 }
 253
 254                 return editor.isEditable();
 255         }
 256
 257         /*
 258          * @see org.eclipse.ui.texteditor.IUpdate#update()
 259          */
 260         public void update() {
 261                 super.update();
 262
 263                 if (isEnabled()) {
 264                         if (!canModifyEditor() || !isValidSelection(getCurrentSelection()))
 265                                 setEnabled(false);
 266                 }
 267         }
 268
 269         /**
 270          * Returns the editor's selection, or <code>null</code> if no selection can be obtained or the
 271          * editor is <code>null</code>.
 272          *
 273          * @return the selection of the action's editor, or <code>null</code>
 274          */
 275         protected ITextSelection getCurrentSelection() {
 276                 ITextEditor editor= getTextEditor();
 277                 if (editor != null) {
 278                         ISelectionProvider provider= editor.getSelectionProvider();
 279                         if (provider != null) {
 280                                 ISelection selection= provider.getSelection();
 281                                 if (selection instanceof ITextSelection)
 282                                         return (ITextSelection) selection;
 283                         }
 284                 }
 285                 return null;
 286         }
 287
 288         /**
 289          * Runs the real command once all the editor, document, and selection checks have succeeded.
 290          *
 291          * @param selection the current selection we are being called for
 292          * @param docExtension the document extension where we get the partitioning from
 293          * @param factory the edit factory we can use to create <code>Edit</code>s
 294          * @throws BadLocationException if an edition fails
 295          * @throws BadPartitioningException if a partitioning call fails
 296          */
 297         protected abstract void runInternal(ITextSelection selection, IDocumentExtension3 docExtension, Edit.EditFactory factory) throws BadLocationException, BadPartitioningException;
 298
 299         /**
 300          * Checks whether <code>selection</code> is valid.
 301          *
 302          * @param selection the selection to check
 303          * @return <code>true</code> if the selection is valid, <code>false</code> otherwise
 304          */
 305         protected abstract boolean isValidSelection(ITextSelection selection);
 306
 307         /**
 308          * Returns the text to be inserted at the selection start.
 309          *
 310          * @return the text to be inserted at the selection start
 311          */
 312         protected String getCommentStart() {
 313                 // for now: no space story
 314                 return "/*"; //$NON-NLS-1$
 315         }
 316
 317         /**
 318          * Returns the text to be inserted at the selection end.
 319          *
 320          * @return the text to be inserted at the selection end
 321          */
 322         protected String getCommentEnd() {
 323                 // for now: no space story
 324                 return "*/"; //$NON-NLS-1$
 325         }
 326
 327 }