trunk/workflowmodel-impl/src/main/java/net/sf/taverna/t2/annotation/AddAnnotationAssertionEdit.java

/*******************************************************************************
 * Copyright (C) 2007 The University of Manchester   
 * 
 *  Modifications to the initial code base are copyright of their
 *  respective authors, or their employers as appropriate.
 * 
 *  This program is free software; you can redistribute it and/or
 *  modify it under the terms of the GNU Lesser General Public License
 *  as published by the Free Software Foundation; either version 2.1 of
 *  the License, or (at your option) any later version.
 *    
 *  This program is distributed in the hope that it will be useful, but
 *  WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 *  Lesser General Public License for more details.
 *    
 *  You should have received a copy of the GNU Lesser General Public
 *  License along with this program; if not, write to the Free Software
 *  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307
 ******************************************************************************/
package net.sf.taverna.t2.annotation;

import net.sf.taverna.t2.workflowmodel.Edit;
import net.sf.taverna.t2.workflowmodel.EditException;

public class AddAnnotationAssertionEdit implements Edit<AnnotationChain> {

	private boolean applied;

	@SuppressWarnings("unchecked")
	private AnnotationAssertion annotationAssertion;
	private AnnotationChain annotationChain;

	@SuppressWarnings("unchecked")
	public AddAnnotationAssertionEdit(AnnotationChain annotationChain,
			AnnotationAssertion annotationAssertion) {
		this.annotationChain = annotationChain;
		this.annotationAssertion = annotationAssertion;
	}

	public AnnotationChain doEdit() throws EditException {
		if (applied) {
			throw new EditException("Edit has already been applied");
		}
		if (!(annotationChain instanceof AnnotationChainImpl)) {
			throw new EditException(
					"Object being edited must be instance of AnnotationChainImpl");
		}

		try {
			synchronized (annotationChain) {
				((AnnotationChainImpl) annotationChain)
						.addAnnotationAssertion(annotationAssertion);
				applied = true;
				return this.annotationChain;
			}
		} catch (Exception e) {
			applied = false;
			throw new EditException("There was a problem with the edit", e);
		}

	}

	public Object getSubject() {
		return annotationChain;
	}

	public boolean isApplied() {
		return applied;
	}

	public void undo() {
		if (!applied) {
			throw new RuntimeException(
					"Attempt to undo edit that was never applied");
		}
		((AnnotationChainImpl)annotationChain).removeAnnotationAssertion(annotationAssertion);
		applied = false;
	}

}