net.sourceforge.phpeclipse.ui/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  * Common block comment code.
  39  *
  40  * @since 3.0
  41  */
  42 public abstract class BlockCommentAction extends TextEditorAction {
  43
  44         /**
  45          * Creates a new instance.
  46          *
  47          * @param bundle
  48          * @param prefix
  49          * @param editor
  50          */
  51         public BlockCommentAction(ResourceBundle bundle, String prefix,
  52                         ITextEditor editor) {
  53                 super(bundle, prefix, editor);
  54         }
  55
  56         /**
  57          * An edit is a kind of <code>DocumentEvent</code>, in this case an edit
  58          * instruction, that is affilitated with a <code>Position</code> on a
  59          * document. The offset of the document event is not stored statically, but
  60          * taken from the affiliated <code>Position</code>, which gets updated
  61          * when other edits occurr.
  62          */
  63         static class Edit extends DocumentEvent {
  64
  65                 /**
  66                  * Factory for edits which manages the creation, installation and
  67                  * destruction of position categories, position updaters etc. on a
  68                  * certain document. Once a factory has been obtained, <code>Edit</code>
  69                  * objects can be obtained from it which will be linked to the document
  70                  * by positions of one position category.
  71                  * <p>
  72                  * Clients are required to call <code>release</code> once the
  73                  * <code>Edit</code>s are not used any more, so the positions can be
  74                  * discarded.
  75                  * </p>
  76                  */
  77                 public static class EditFactory {
  78
  79                         /** The position category basename for this edits. */
  80                         private static final String CATEGORY = "__positionalEditPositionCategory"; //$NON-NLS-1$
  81
  82                         /** The count of factories. */
  83                         private static int fgCount = 0;
  84
  85                         /** This factory's category. */
  86                         private final String fCategory;
  87
  88                         private IDocument fDocument;
  89
  90                         private IPositionUpdater fUpdater;
  91
  92                         /**
  93                          * Creates a new <code>EditFactory</code> with an unambiguous
  94                          * position category name.
  95                          *
  96                          * @param document
  97                          *            the document that is being edited.
  98                          */
  99                         public EditFactory(IDocument document) {
 100                                 fCategory = CATEGORY + fgCount++;
 101                                 fDocument = document;
 102                         }
 103
 104                         /**
 105                          * Creates a new edition on the document of this factory.
 106                          *
 107                          * @param offset
 108                          *            the offset of the edition at the point when is
 109                          *            created.
 110                          * @param length
 111                          *            the length of the edition (not updated via the
 112                          *            position update mechanism)
 113                          * @param text
 114                          *            the text to be replaced on the document
 115                          * @return an <code>Edit</code> reflecting the edition on the
 116                          *         document
 117                          */
 118                         public Edit createEdit(int offset, int length, String text)
 119                                         throws BadLocationException {
 120
 121                                 if (!fDocument.containsPositionCategory(fCategory)) {
 122                                         fDocument.addPositionCategory(fCategory);
 123                                         fUpdater = new DefaultPositionUpdater(fCategory);
 124                                         fDocument.addPositionUpdater(fUpdater);
 125                                 }
 126
 127                                 Position position = new Position(offset);
 128                                 try {
 129                                         fDocument.addPosition(fCategory, position);
 130                                 } catch (BadPositionCategoryException e) {
 131                                         Assert.isTrue(false);
 132                                 }
 133                                 return new Edit(fDocument, length, text, position);
 134                         }
 135
 136                         /**
 137                          * Releases the position category on the document and uninstalls the
 138                          * position updater. <code>Edit</code>s managed by this factory
 139                          * are not updated after this call.
 140                          */
 141                         public void release() {
 142                                 if (fDocument != null
 143                                                 && fDocument.containsPositionCategory(fCategory)) {
 144                                         fDocument.removePositionUpdater(fUpdater);
 145                                         try {
 146                                                 fDocument.removePositionCategory(fCategory);
 147                                         } catch (BadPositionCategoryException e) {
 148                                                 Assert.isTrue(false);
 149                                         }
 150                                         fDocument = null;
 151                                         fUpdater = null;
 152                                 }
 153                         }
 154                 }
 155
 156                 /** The position in the document where this edit be executed. */
 157                 private Position fPosition;
 158
 159                 /**
 160                  * Creates a new edition on <code>document</code>, taking its offset
 161                  * from <code>position</code>.
 162                  *
 163                  * @param document
 164                  *            the document being edited
 165                  * @param length
 166                  *            the length of the edition
 167                  * @param text
 168                  *            the replacement text of the edition
 169                  * @param position
 170                  *            the position keeping the edition's offset
 171                  */
 172                 protected Edit(IDocument document, int length, String text,
 173                                 Position position) {
 174                         super(document, 0, length, text);
 175                         fPosition = position;
 176                 }
 177
 178                 /*
 179                  * @see org.eclipse.jface.text.DocumentEvent#getOffset()
 180                  */
 181                 public int getOffset() {
 182                         return fPosition.getOffset();
 183                 }
 184
 185                 /**
 186                  * Executes the edition on document. The offset is taken from the
 187                  * position.
 188                  *
 189                  * @throws BadLocationException
 190                  *             if the execution of the document fails.
 191                  */
 192                 public void perform() throws BadLocationException {
 193                         getDocument().replace(getOffset(), getLength(), getText());
 194                 }
 195
 196         }
 197
 198         public void run() {
 199                 if (!isEnabled())
 200                         return;
 201
 202                 ITextEditor editor = getTextEditor();
 203                 if (editor == null || !ensureEditable(editor))
 204                         return;
 205
 206                 ITextSelection selection = getCurrentSelection();
 207                 if (!isValidSelection(selection))
 208                         return;
 209
 210                 if (!validateEditorInputState())
 211                         return;
 212
 213                 IDocumentProvider docProvider = editor.getDocumentProvider();
 214                 IEditorInput input = editor.getEditorInput();
 215                 if (docProvider == null || input == null)
 216                         return;
 217
 218                 IDocument document = docProvider.getDocument(input);
 219                 if (document == null)
 220                         return;
 221
 222                 IDocumentExtension3 docExtension;
 223                 if (document instanceof IDocumentExtension3)
 224                         docExtension = (IDocumentExtension3) document;
 225                 else
 226                         return;
 227
 228                 IRewriteTarget target = (IRewriteTarget) editor
 229                                 .getAdapter(IRewriteTarget.class);
 230                 if (target != null) {
 231                         target.beginCompoundChange();
 232                 }
 233
 234                 Edit.EditFactory factory = new Edit.EditFactory(document);
 235
 236                 try {
 237                         runInternal(selection, docExtension, factory);
 238
 239                 } catch (BadLocationException e) {
 240                         // can happen on concurrent modification, deletion etc. of the
 241                         // document
 242                         // -> don't complain, just bail out
 243                 } catch (BadPartitioningException e) {
 244                         // should not happen
 245                         Assert.isTrue(false, "bad partitioning"); //$NON-NLS-1$
 246                 } finally {
 247                         factory.release();
 248
 249                         if (target != null) {
 250                                 target.endCompoundChange();
 251                         }
 252                 }
 253         }
 254
 255         /**
 256          * Calls <code>perform</code> on all <code>Edit</code>s in
 257          * <code>edits</code>.
 258          *
 259          * @param edits
 260          *            a list of <code>Edit</code>s
 261          * @throws BadLocationException
 262          *             if an <code>Edit</code> threw such an exception.
 263          */
 264         protected void executeEdits(List edits) throws BadLocationException {
 265                 for (Iterator it = edits.iterator(); it.hasNext();) {
 266                         Edit edit = (Edit) it.next();
 267                         edit.perform();
 268                 }
 269         }
 270
 271         /**
 272          * Ensures that the editor is modifyable. If the editor is an instance of
 273          * <code>ITextEditorExtension2</code>, its
 274          * <code>validateEditorInputState</code> method is called, otherwise, the
 275          * result of <code>isEditable</code> is returned.
 276          *
 277          * @param editor
 278          *            the editor to be checked
 279          * @return <code>true</code> if the editor is editable, <code>false</code>
 280          *         otherwise
 281          */
 282         protected boolean ensureEditable(ITextEditor editor) {
 283                 Assert.isNotNull(editor);
 284
 285                 if (editor instanceof ITextEditorExtension2) {
 286                         ITextEditorExtension2 ext = (ITextEditorExtension2) editor;
 287                         return ext.validateEditorInputState();
 288                 }
 289
 290                 return editor.isEditable();
 291         }
 292
 293         /*
 294          * @see org.eclipse.ui.texteditor.IUpdate#update()
 295          */
 296         public void update() {
 297                 super.update();
 298
 299                 if (isEnabled()) {
 300                         if (!canModifyEditor() || !isValidSelection(getCurrentSelection()))
 301                                 setEnabled(false);
 302                 }
 303         }
 304
 305         /**
 306          * Returns the editor's selection, or <code>null</code> if no selection
 307          * can be obtained or the editor is <code>null</code>.
 308          *
 309          * @return the selection of the action's editor, or <code>null</code>
 310          */
 311         protected ITextSelection getCurrentSelection() {
 312                 ITextEditor editor = getTextEditor();
 313                 if (editor != null) {
 314                         ISelectionProvider provider = editor.getSelectionProvider();
 315                         if (provider != null) {
 316                                 ISelection selection = provider.getSelection();
 317                                 if (selection instanceof ITextSelection)
 318                                         return (ITextSelection) selection;
 319                         }
 320                 }
 321                 return null;
 322         }
 323
 324         /**
 325          * Runs the real command once all the editor, document, and selection checks
 326          * have succeeded.
 327          *
 328          * @param selection
 329          *            the current selection we are being called for
 330          * @param docExtension
 331          *            the document extension where we get the partitioning from
 332          * @param factory
 333          *            the edit factory we can use to create <code>Edit</code>s
 334          * @throws BadLocationException
 335          *             if an edition fails
 336          * @throws BadPartitioningException
 337          *             if a partitioning call fails
 338          */
 339         protected abstract void runInternal(ITextSelection selection,
 340                         IDocumentExtension3 docExtension, Edit.EditFactory factory)
 341                         throws BadLocationException, BadPartitioningException;
 342
 343         /**
 344          * Checks whether <code>selection</code> is valid.
 345          *
 346          * @param selection
 347          *            the selection to check
 348          * @return <code>true</code> if the selection is valid, <code>false</code>
 349          *         otherwise
 350          */
 351         protected abstract boolean isValidSelection(ITextSelection selection);
 352
 353         /**
 354          * Returns the text to be inserted at the selection start.
 355          *
 356          * @return the text to be inserted at the selection start
 357          */
 358         protected String getCommentStart() {
 359                 // for now: no space story
 360                 return "/*"; //$NON-NLS-1$
 361         }
 362
 363         /**
 364          * Returns the text to be inserted at the selection end.
 365          *
 366          * @return the text to be inserted at the selection end
 367          */
 368         protected String getCommentEnd() {
 369                 // for now: no space story
 370                 return "*/"; //$NON-NLS-1$
 371         }
 372
 373 }