org.eclipse.gmf.runtime.emf.ui/src/org/eclipse/gmf/runtime/emf/ui/action/AbstractModelActionDelegate.java

/******************************************************************************
 * Copyright (c) 2002, 2006 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.gmf.runtime.emf.ui.action;

import org.eclipse.core.commands.ExecutionException;
import org.eclipse.core.commands.operations.IUndoableOperation;
import org.eclipse.core.runtime.IAdaptable;
import org.eclipse.core.runtime.IProgressMonitor;
import org.eclipse.core.runtime.IStatus;
import org.eclipse.core.runtime.NullProgressMonitor;
import org.eclipse.core.runtime.Status;
import org.eclipse.emf.transaction.TransactionalEditingDomain;
import org.eclipse.gmf.runtime.common.core.util.Log;
import org.eclipse.gmf.runtime.common.core.util.Trace;
import org.eclipse.gmf.runtime.common.ui.action.AbstractActionDelegate;
import org.eclipse.gmf.runtime.common.ui.action.IActionWithProgress;
import org.eclipse.gmf.runtime.emf.ui.internal.MslUIDebugOptions;
import org.eclipse.gmf.runtime.emf.ui.internal.MslUIPlugin;
import org.eclipse.gmf.runtime.emf.ui.internal.MslUIStatusCodes;

/**
 * The abstract parent of all concrete action delegates that execute model
 * commands. Concrete subclasses must provide a definition of the
 * <code>doRun()</code> method to gather any required input and execute a
 * model command.
 * <P>
 * Subclasses that execute a command must return <code>false</code>from
 * {@link #isReadOnly()}. The superclass performs the
 * {@link #doRun(IProgressMonitor)} method in an EMF operation executed on the
 * operation history. Subclasses should set the action delegate status using
 * {@link #setStatus(IStatus)} to their command execution status.
 * <P>
 * Subclasses that only want to read from the model must return
 * <code>true</code> from {@link #isReadOnly()}.
 * 
 * @author khussey
 * @auther ldamus
 */
public abstract class AbstractModelActionDelegate
	extends AbstractActionDelegate {
    
    private IStatus status;
    
    /**
     * Intializes me with the singleton editing domain.
     */
    protected AbstractModelActionDelegate() {
        super();
    }

	/**
     * Runs this model action delegate as a read action.
     * 
     * @see IActionWithProgress#run(IProgressMonitor)
     */
    public final void run(final IProgressMonitor progressMonitor) {

        if (isReadOnly()) {
            // run exclusive so that subclasses can only read from the model
            try {
                getEditingDomain().runExclusive(new Runnable() {

                    public void run() {
                        AbstractModelActionDelegate.super.run(progressMonitor);
                    }
                });
            } catch (InterruptedException e) {
                Trace
                    .catching(MslUIPlugin.getDefault(),
                        MslUIDebugOptions.EXCEPTIONS_CATCHING, getClass(),
                        "run", e); //$NON-NLS-1$
            }

        } else {
            // Run in a composite transactional operation so that subclasses can
			// both read and write to the model. Commands executed by subclasses
			// to modify the model will be appended to this composite
			// transactional operation.
        	
        	Runnable runnable = new Runnable() {
				public void run() {
					AbstractModelActionDelegate.super
							.run(progressMonitor);
				}
			};
			
        	WriteCommand write = new WriteCommand(getEditingDomain(),
					getLabel(), getActionManager().getOperationHistory(),
					runnable) {
        		
				public IStatus getStatus() {
					return AbstractModelActionDelegate.this.getStatus();
				}
			};

            execute(write, new NullProgressMonitor(), null);
        }
    }
    
    /**
     * Gets my editing domain. Can be <code>null</code> if I don't modify
     * model resources.
     * 
     * @return my editing domain.
     */
    protected abstract TransactionalEditingDomain getEditingDomain();
    
    /**
     * Answers whether or not I am a read-only action. Returns
     * <code>false</code> by default. Subclasses may override.
     * 
     * @return <code>false</code>
     */
    protected boolean isReadOnly() {
        return false;
    }
    
    /**
     * Gets the status of running this action delegate.
     * 
     * @return my status
     */
    protected IStatus getStatus() {
        if (status == null) {
            return Status.OK_STATUS;
        }
        return status;
    }
    
    /**
     * Sets the action delegate status. Subclasses should set the status when they
     * execute a command.
     * 
     * @param status
     *            the new status
     */
    protected void setStatus(IStatus status) {
        this.status = status;
    }
    
    /**
	 * Convenience method for subclasses to execute an undoable operation on the
	 * action manager's operation history. Sets my status to the status of the
	 * operation execution, and returns that status.
	 * 
	 * @param operation
	 *            the operation to be executed
	 * @param progressMonitor
	 *            the progress monitor
	 * @param info
	 *            the adaptable info, may be <code>null</code>
	 * @return the status of the operation execution.
	 */
	protected IStatus execute(IUndoableOperation operation,
			IProgressMonitor progressMonitor, IAdaptable info) {

		try {
			setStatus(getActionManager().getOperationHistory().execute(
					operation, progressMonitor, info));

		} catch (ExecutionException e) {
			setStatus(new Status(Status.ERROR, MslUIPlugin.getPluginId(),
					MslUIStatusCodes.IGNORED_EXCEPTION_WARNING, e
							.getLocalizedMessage(), e));
			Trace
					.catching(MslUIPlugin.getDefault(),
							MslUIDebugOptions.EXCEPTIONS_CATCHING, getClass(),
							"run", e); //$NON-NLS-1$
			Log.error(MslUIPlugin.getDefault(),
					MslUIStatusCodes.IGNORED_EXCEPTION_WARNING, e
							.getLocalizedMessage(), e);
		}
		return getStatus();
	}
}