/**********************************************************************
Copyright (c) 2000, 2002 IBM Corp. and others.
All rights reserved. This program and the accompanying materials
are made available under the terms of the Common Public License v0.5
which accompanies this distribution, and is available at
http://www.eclipse.org/legal/cpl-v05.html

Contributors:
    IBM Corporation - Initial API and implementation
**********************************************************************/
package org.eclipse.ui.texteditor;


/**
 * Extension interface for actions. Actions implementing this interface not
 * only manage an enable/disable state but also manage a "hypothetical"
 * enable state, depending on whether the target they work on is writable
 * or read-only.
 */
public interface IReadOnlyDependent {

	/**
	 * Returns whether the actions would be enabled if its target
	 * would be enabled given the writable state described by <code>isWritable</code>.
	 * <code>isEnabled()</code> and <code>isEnabled(boolean)</code> holds the following
	 * invariants:
	 * 	isEnabled() == false, iff isEnabled(true) == false || isEnabled(false) == false
	 * 	isEnabled() == true, iff isEnabled(true) == true || isEnabled(false) == true
	 * 
	 * @param isWritable
	 * @return the hypothetical enable state of the action
	 */
	boolean isEnabled(boolean isWritable);
}