bundles/org.eclipse.wst.sse.ui/src/org/eclipse/wst/sse/ui/internal/handlers/AddBlockCommentHandler.java

/*******************************************************************************
 * Copyright (c) 2010 IBM Corporation and others.
 * All rights reserved. This program and the accompanying materials
 * are made available under the terms of the Eclipse Public License v1.0
 * which accompanies this distribution, and is available at
 * http://www.eclipse.org/legal/epl-v10.html
 * 
 * Contributors:
 *     IBM Corporation - initial API and implementation
 *******************************************************************************/
package org.eclipse.wst.sse.ui.internal.handlers;

import org.eclipse.jface.text.BadLocationException;
import org.eclipse.jface.text.DocumentRewriteSession;
import org.eclipse.jface.text.DocumentRewriteSessionType;
import org.eclipse.jface.text.IDocumentExtension4;
import org.eclipse.jface.text.ITextSelection;
import org.eclipse.jface.text.ITypedRegion;
import org.eclipse.ui.texteditor.ITextEditor;
import org.eclipse.wst.sse.core.StructuredModelManager;
import org.eclipse.wst.sse.core.internal.Logger;
import org.eclipse.wst.sse.core.internal.provisional.IStructuredModel;
import org.eclipse.wst.sse.core.internal.provisional.text.IStructuredDocument;
import org.eclipse.wst.sse.ui.internal.SSEUIMessages;
import org.eclipse.wst.sse.ui.internal.comment.CommentingStrategy;
import org.eclipse.wst.sse.ui.internal.comment.CommentingStrategyRegistry;

/**
 * <p>A comment handler to add block comments</p>
 */
public final class AddBlockCommentHandler extends
		AbstractCommentHandler {

	/**
	 * @see org.eclipse.wst.sse.ui.internal.handlers.AbstractCommentHandler#processAction(
	 * 	org.eclipse.ui.texteditor.ITextEditor, org.eclipse.jface.text.IDocument, org.eclipse.jface.text.ITextSelection)
	 */
	protected void processAction(ITextEditor textEditor, IStructuredDocument document, ITextSelection textSelection) {
		IStructuredModel model = null;
		boolean changed = false;
		DocumentRewriteSession session = null;
		
		try {
			model = StructuredModelManager.getModelManager().getModelForEdit(document);
			if(model != null) {
				//makes it so one undo will undo all the edits to the document
				model.beginRecording(this, SSEUIMessages.AddBlockComment_label, SSEUIMessages.AddBlockComment_description);
				
				//keeps listeners from doing anything until updates are all done
				model.aboutToChangeModel();
				if(document instanceof IDocumentExtension4) {
					session = ((IDocumentExtension4)document).startRewriteSession(DocumentRewriteSessionType.UNRESTRICTED);
				}
				changed = true;
				
				ITypedRegion[] typedRegions = document.computePartitioning(textSelection.getOffset(), textSelection.getLength());
				CommentingStrategy commentType = CommentingStrategyRegistry.getDefault().getBlockCommentingStrategy(model.getContentTypeIdentifier(), typedRegions);
				
				if(commentType != null) {
					commentType.apply(document, textSelection.getOffset(), textSelection.getLength());
				}
			}
		} catch (BadLocationException e) {
			Logger.logException("The given selection " + textSelection + " must be invalid", e); //$NON-NLS-1$ //$NON-NLS-2$
		} finally {
			//clean everything up
			if(session != null && document instanceof IDocumentExtension4) {
				((IDocumentExtension4)document).stopRewriteSession(session);
			}
			
			if(model != null) {
				model.endRecording(this);
				if(changed) {
					model.changedModel();
				}
				model.releaseFromEdit();
			}
		}
	}
}