bundles/org.eclipse.emf.emfstore.client.transaction/src/org/eclipse/emf/emfstore/internal/client/transaction/EMFStoreTransactionalCommandStack.java

/*******************************************************************************
 * Copyright (c) 2008-2011 Chair for Applied Software Engineering,
 * Technische Universitaet Muenchen.
 * 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:
 * Maximilian Koegel - initial API and implementation
 ******************************************************************************/
package org.eclipse.emf.emfstore.internal.client.transaction;

import java.util.Iterator;

import org.eclipse.core.runtime.OperationCanceledException;
import org.eclipse.emf.common.command.Command;
import org.eclipse.emf.emfstore.client.changetracking.ESCommandObserver;
import org.eclipse.emf.emfstore.client.changetracking.ESCommandStack;
import org.eclipse.emf.emfstore.internal.client.model.ESWorkspaceProviderImpl;
import org.eclipse.emf.emfstore.internal.client.model.changeTracking.commands.EMFStoreCommandNotifier;
import org.eclipse.emf.emfstore.internal.client.model.util.AbstractEMFStoreCommand;
import org.eclipse.emf.transaction.RecordingCommand;
import org.eclipse.emf.transaction.RollbackException;
import org.eclipse.emf.transaction.TransactionalEditingDomain;

/**
 * Command Stack with additional support for command listing.
 *
 * @author koegel
 */
public class EMFStoreTransactionalCommandStack extends AbstractEMFStoreTransactionalCommandStackImpl implements
	ESCommandStack {

	private Command currentCommand;
	private final EMFStoreCommandNotifier notifier;

	/**
	 * Default Constructor.
	 */
	public EMFStoreTransactionalCommandStack() {
		notifier = new EMFStoreCommandNotifier();
	}

	@Override
	public void execute(final Command command) {
		// handle EMFStore commands
		if (command instanceof AbstractEMFStoreCommand) {
			runEMFStoreCommand((AbstractEMFStoreCommand) command);
			return;
		}
		super.execute(command);
	}

	private void runEMFStoreCommand(final AbstractEMFStoreCommand cmd) {
		// wrap EMFStoreCommands in RecordingCommands
		final RecordingCommand recordingCommand = new RecordingCommand(
			(TransactionalEditingDomain) ESWorkspaceProviderImpl.getInstance().getEditingDomain()) {
			@Override
			protected void doExecute() {
				cmd.execute();
			}
		};
		super.execute(recordingCommand);

		// rethrow runtime exceptions if neccessary
		if (!cmd.shouldIgnoreExceptions() && cmd.getRuntimeException() != null) {
			throw cmd.getRuntimeException();
		}
	}

	@Override
	protected void basicRedo() {
		notifier.notifiyListenersAboutStart(mostRecentCommand);
		redoOfBasicCommandStack();
		rethrowComamndInCaseOfError(mostRecentCommand);
		notifier.notifiyListenersAboutCommandCompleted(mostRecentCommand);
	}

	@Override
	protected void basicUndo() {
		notifier.notifiyListenersAboutStart(mostRecentCommand);
		undoOfBasicCommandStack();
		rethrowComamndInCaseOfError(mostRecentCommand);
		notifier.notifiyListenersAboutCommandCompleted(mostRecentCommand);
	}

	private void redoOfBasicCommandStack() {
		final Command command = commandList.get(++top);

		try {
			command.redo();
			mostRecentCommand = command;
			// BEGIN SUPRESS CATCH EXCEPTION
		} catch (final RuntimeException exception)
		// END SUPRESS CATCH EXCEPTION
		{
			handleError(exception);

			mostRecentCommand = null;

			// Clear the list past the top.
			//
			for (final Iterator<Command> commands = commandList.listIterator(top--); commands.hasNext(); commands
				.remove()) {
				final Command otherCommand = commands.next();
				otherCommand.dispose();
			}
		}

		notifyListeners();
	}

	private void undoOfBasicCommandStack() {
		final Command command = commandList.get(top--);
		try {
			command.undo();
			mostRecentCommand = command;
			// BEGIN SUPRESS CATCH EXCEPTION
		} catch (final RuntimeException exception)
		// END SUPRESS CATCH EXCEPTION
		{
			handleError(exception);

			mostRecentCommand = null;
			flush();
		}

		notifyListeners();
		// ((BasicCommandStack) this).undo();
	}

	private void rethrowComamndInCaseOfError(Command command) {
		// handle EMFStore commands
		if (command instanceof AbstractEMFStoreCommand) {
			final AbstractEMFStoreCommand emfStoreCmd = (AbstractEMFStoreCommand) command;

			// rethrow runtime exceptions if neccessary
			if (!emfStoreCmd.shouldIgnoreExceptions() && emfStoreCmd.getRuntimeException() != null) {
				throw emfStoreCmd.getRuntimeException();
			}
		}
	}

	/**
	 * {@inheritDoc}
	 *
	 * @see org.eclipse.emf.transaction.impl.AbstractTransactionalCommandStack#basicExecute(org.eclipse.emf.common.command.Command)
	 */
	@Override
	protected void basicExecute(Command command) {
		// Notify about the command started!
		// check if we are already inside of a command, if not then notify.
		if (currentCommand == null) {
			currentCommand = command;
			notifier.notifiyListenersAboutStart(command);
		}

		try {
			super.basicExecute(command);
		} catch (final OperationCanceledException e) {
			notifier.notifiyListenersAboutCommandFailed(command, e);
			currentCommand = null;
			throw e;
		}

		// Notify someone that the command is done.
		// Check if we are really at the end of the most outer command.
		if (currentCommand == command) {
			// check again if command was really completed.
			if (mostRecentCommand == command) {
				notifier.notifiyListenersAboutCommandCompleted(command);
			}
			currentCommand = null;
		}
	}

	/**
	 * {@inheritDoc}
	 *
	 * @see org.eclipse.emf.transaction.impl.TransactionalCommandStackImpl#handleRollback(org.eclipse.emf.common.command.Command,
	 *      org.eclipse.emf.transaction.RollbackException)
	 */
	@Override
	protected void handleRollback(Command command, RollbackException rbe) {
		super.handleRollback(command, rbe);
		Exception exception = null;
		if (rbe != null) {
			if (rbe.getCause() != null && rbe.getCause() instanceof Exception) {
				exception = (Exception) rbe.getCause();
			} else {
				exception = rbe;
			}
		}
		notifier.notifiyListenersAboutCommandFailed(command, exception);

		if (currentCommand == command) {
			currentCommand = null;
		}
	}

	/**
	 * {@inheritDoc}
	 *
	 * @see org.eclipse.emf.emfstore.client.changetracking.ESCommandStack#addCommandStackObserver(org.eclipse.emf.emfstore.client.changetracking.ESCommandObserver)
	 */
	public void addCommandStackObserver(ESCommandObserver observer) {
		notifier.addCommandStackObserver(observer);
	}

	/**
	 * {@inheritDoc}
	 *
	 * @see org.eclipse.emf.emfstore.client.changetracking.ESCommandStack#removeCommandStackObserver(org.eclipse.emf.emfstore.client.changetracking.ESCommandObserver)
	 */
	public void removeCommandStackObserver(ESCommandObserver observer) {
		notifier.removeCommandStackObserver(observer);
	}
}