UpdateXtextResourceTextCommand.java

/*******************************************************************************
 * Copyright (c) 2009 itemis AG (http://www.itemis.eu) 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
 *******************************************************************************/
package org.eclipse.xtext.gmf.glue.editingdomain;

import org.eclipse.core.commands.ExecutionException;
import org.eclipse.core.runtime.IAdaptable;
import org.eclipse.core.runtime.IProgressMonitor;
import org.eclipse.emf.common.command.Command;
import org.eclipse.emf.ecore.resource.ResourceSet;
import org.eclipse.emf.ecore.util.EcoreUtil;
import org.eclipse.emf.transaction.RecordingCommand;
import org.eclipse.emf.transaction.TransactionalEditingDomain;
import org.eclipse.emf.transaction.util.TransactionUtil;
import org.eclipse.gmf.runtime.common.core.command.CommandResult;
import org.eclipse.gmf.runtime.common.core.command.ICommand;
import org.eclipse.gmf.runtime.emf.commands.core.command.AbstractTransactionalCommand;
import org.eclipse.xtext.resource.XtextResource;

/**
 * A Command that deactivates the {@link ChangeAggregatorAdapter} and updates a textual section of an Xtext model in an
 * Xtext resource. Used to avoid cycles in the change aggregation.
 * 
 * @author koehnlein
 */
public class UpdateXtextResourceTextCommand {

	/**
	 * This element comes from the XText/GMF integration example, and was not originally documented.
	 * @param xtextResource 
	 * @param offset 
	 * @param length 
	 * @param newText 
	 * @return Command
	 */
	public static Command createEMFCommand(final XtextResource xtextResource, final int offset, final int length,
			final String newText) {
		final TransactionalEditingDomain editingDomain = TransactionUtil.getEditingDomain(xtextResource);
		if (editingDomain == null) {
			return null;
		}
		ResourceSet resourceSet = editingDomain.getResourceSet();
		final ChangeAggregatorAdapter changeAggregator = (ChangeAggregatorAdapter) EcoreUtil.getAdapter(resourceSet
				.eAdapters(), ChangeAggregatorAdapter.class);
		return new RecordingCommand(editingDomain, "update xtext resource") {
			@Override
			protected void doExecute() {
				try {
					if (changeAggregator != null) {
						changeAggregator.setSuspended(true);
					}
					xtextResource.update(offset, length, newText);
					xtextResource.setModified(true);
				} finally {
					if (changeAggregator != null) {
						changeAggregator.setSuspended(false);
					}
				}

			}
		};
	}

	/**
	 * This element comes from the XText/GMF integration example, and was not originally documented.
	 * @param xtextResource 
	 * @param offset 
	 * @param length 
	 * @param newText 
	 * @return ICommand
	 */
	public static ICommand createUpdateCommand(final XtextResource xtextResource, final int offset, final int length,
			final String newText) {
		final TransactionalEditingDomain editingDomain = TransactionUtil.getEditingDomain(xtextResource);
		if (editingDomain == null) {
			return null;
		}
		ResourceSet resourceSet = editingDomain.getResourceSet();
		final ChangeAggregatorAdapter changeAggregator = (ChangeAggregatorAdapter) EcoreUtil.getAdapter(resourceSet
				.eAdapters(), ChangeAggregatorAdapter.class);
		return new AbstractTransactionalCommand(editingDomain, "update xtext resource", null) {
			@Override
			protected CommandResult doExecuteWithResult(IProgressMonitor monitor, IAdaptable info)
					throws ExecutionException {
				try {
					if (changeAggregator != null) {
						changeAggregator.setSuspended(true);
					}
					xtextResource.update(offset, length, newText);
					xtextResource.setModified(true);
					return CommandResult.newOKCommandResult();
				} catch (Exception exc) {
					return CommandResult.newErrorCommandResult(exc);
				} finally {
					if (changeAggregator != null) {
						changeAggregator.setSuspended(false);
					}
				}
			}
		};
	}

}