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//
//  Licensed to the Apache Software Foundation (ASF) under one or more
//  contributor license agreements.  See the NOTICE file distributed with
//  this work for additional information regarding copyright ownership.
//  The ASF licenses this file to You under the Apache License, Version 2.0
//  (the "License"); you may not use this file except in compliance with
//  the License.  You may obtain a copy of the License at
//
//      http://www.apache.org/licenses/LICENSE-2.0
//
//  Unless required by applicable law or agreed to in writing, software
//  distributed under the License is distributed on an "AS IS" BASIS,
//  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
//  See the License for the specific language governing permissions and
//  limitations under the License.
//
////////////////////////////////////////////////////////////////////////////////
package flashx.undo
{	
	/**
	 * IUndoManager defines the interface for managing the undo and redo stacks.
	 * 
	 * <p>An undo manager maintains a stack of operations that can be undone and redone.</p>
	 * 
	 * @playerversion Flash 10
	 * @playerversion AIR 1.5
 	 * @langversion 3.0
	 */
	public interface IUndoManager 
	{	
		/**
		 * Clears both the undo and the redo histories.
		 * 
		 * @playerversion Flash 10
		 * @playerversion AIR 1.5
 	 	 * @langversion 3.0
		 */	
		function clearAll():void;
		
		/**
		 * The maximum number of undoable or redoable operations to track.
		 * 
		 * <p>To disable the undo function, set this value to 0.</p> 
		 * 
		 * @playerversion Flash 10
		 * @playerversion AIR 1.5
 	 	 * @langversion 3.0
		 */
		function get undoAndRedoItemLimit():int;
		function set undoAndRedoItemLimit(value:int):void;

		/**
		 * Indicates whether there is currently an operation that can be undone.
		 * 
		 * @return Boolean <code>true</code>, if there is an operation on the undo stack that can be reversed.
		 * Otherwise, <code>false</code>.
		 * 
		 * @playerversion Flash 10
		 * @playerversion AIR 1.5
 	 	 * @langversion 3.0
		 */
		function canUndo():Boolean;
		
		/**
		 * Returns the next operation to be undone.
		 * 
		 * @return IOperation The undoable IOperation object, or <code>null</code>, if no undoable operation
		 * is on the stack.
		 * 
		 * @playerversion Flash 10
		 * @playerversion AIR 1.5
 	 	 * @langversion 3.0
		 */
		function peekUndo():IOperation;
		
		/**
		 * Removes the next operation to be undone from the undo stack, and returns it.
		 * 
		 * @return IOperation The undoable IOperation object, or <code>null</code>, if no undoable operation
		 * is on the stack.
		 * 
		 * @playerversion Flash 10
		 * @playerversion AIR 1.5
 	 	 * @langversion 3.0
		 */
		function popUndo():IOperation;

		/**
		 * Adds an undoable operation to the undo stack.
		 * 
		 * @playerversion Flash 10
		 * @playerversion AIR 1.5
 	 	 * @langversion 3.0
		 */
		function pushUndo(operation:IOperation):void;
		
		/**
		 * Clears the redo stack.
		 * 
		 * @playerversion Flash 10
		 * @playerversion AIR 1.5
 	 	 * @langversion 3.0
		 */
		function clearRedo():void;

		/**
		 * Indicates whether there is currently an operation that can be redone.
		 * 
		 * @return Boolean <code>true</code>, if there is an operation on the redo stack that can be redone.
		 * Otherwise, <code>false</code>.
		 * 
		 * @playerversion Flash 10
		 * @playerversion AIR 1.5
 	 	 * @langversion 3.0
		 */
		function canRedo():Boolean;

		/**
		 * Returns the next operation to be redone.
		 * 
		 * @return IOperation The redoable IOperation object, or <code>null</code>, if no redoable operation
		 * is on the stack.
		 * 
		 * @playerversion Flash 10
		 * @playerversion AIR 1.5
 	 	 * @langversion 3.0
		 */
		function peekRedo():IOperation;
		
		/**
		 * Removes the next operation to be redone from the redo stack, and returns it.
		 * 
		 * @return IOperation The redoable IOperation object, or <code>null</code>, if no redoable operation
		 * is on the stack.
		 * @playerversion Flash 10
		 * @playerversion AIR 1.5
 	 	 * @langversion 3.0
		 */
		function popRedo():IOperation;

		/**
		 * Adds a redoable operation to the redo stack.
		 * 
		 * @playerversion Flash 10
		 * @playerversion AIR 1.5
 	 	 * @langversion 3.0
		 */
		function pushRedo(operation:IOperation):void;

		/** 
		 * Removes the next IOperation object from the undo stack and calls the performUndo() 
		 * function of that object.
		 * 
		 * @see flashx.textLayout.edit.IEditManager#undo()
		 * @see flashx.undo.IUndoManager#canUndo()
		 * @see flashx.undo.IUndoManager#clearUndo()
		 * @see flashx.undo.IUndoManager#peekUndo()
		 * @see flashx.undo.IUndoManager#pushUndo()
		 * @see flashx.undo.IUndoManager#popUndo()
		 */
		function undo():void;
		
		/** 
		 * Removes the next IOperation object from the redo stack and calls the performRedo() 
		 * function of that object.
		 * 
		 * @see flashx.textLayout.edit.IEditManager#redo()
		 * @see flashx.undo.IUndoManager#canRedo()
		 * @see flashx.undo.IUndoManager#clearRedo()
		 * @see flashx.undo.IUndoManager#peekRedo()
		 * @see flashx.undo.IUndoManager#pushRedo()
		 * @see flashx.undo.IUndoManager#popRedo()
		 */
		function redo():void;						
	}
}