Bug 125420 [Commands] parameters: allow commands to specify return type
bundles/org.eclipse.core.commands/src/org/eclipse/core/commands/CommandEvent.java
*            <code>true</code>, iff the handled property changed.
	 * @param nameChanged
	 *            <code>true</code>, iff the name property changed.
	 * @param parametersChanged
	 *            <code>true</code> if the parameters have changed;
	 *            <code>false</code> otherwise.
	 */
	public CommandEvent(final Command command, final boolean categoryChanged,
			final boolean definedChanged, final boolean descriptionChanged,
			final boolean handledChanged, final boolean nameChanged,
			final boolean parametersChanged) {
		super(definedChanged, descriptionChanged, nameChanged);
		if (command == null)
			throw new NullPointerException();
		this.command = command;
		if (categoryChanged) {
			changedValues |= CHANGED_CATEGORY;
		}
		if (handledChanged) {
			changedValues |= CHANGED_HANDLED;
		}
		if (parametersChanged) {
			changedValues |= CHANGED_PARAMETERS;
		}
	}
	/**
	 * Returns the instance of the interface that changed.
	 * 
	 * @return the instance of the interface that changed. Guaranteed not to be
	 *         <code>null</code>.