//---------------------------------------------------------------------------
//
// <copyright file=IUndoUnit.cs company=Microsoft>
//    Copyright (C) Microsoft Corporation.  All rights reserved.
// </copyright>
// 
//
// Description: 
//
//              See spec at http://avalon/uis/Stock%20Services/Undo%20spec.htm 
// 
// History:  
//  07/21/2003 : psarrett   ported to WCP tree
//
//---------------------------------------------------------------------------
 
using System;
 
namespace MS.Internal.Documents
{
    /// <summary>
    /// IUndoUnit interface
    /// </summary>
    /// 
    internal interface IUndoUnit
    {
        //------------------------------------------------------
        //
        //  Constructors
        //
        //------------------------------------------------------
 
        //------------------------------------------------------
        //
        //  Public Methods
        //
        //------------------------------------------------------
 
        #region Public Methods
 
        /// <summary>
        /// Perform the appropriate action for this unit.  If this is a parent undo unit, the
        /// parent must create an appropriate parent undo unit to contain the redo units.
        /// </summary>
        void Do();
 
        /// <summary>
        /// Attempt to merge the given undo unit with this unit.
        /// Merge is typically called by a ParentUndoUnit's Add() method.  If the merge
        /// succeeds, the parent should not add the merged unit.
        /// </summary>
        /// <param name="unit">Unit to merge into this one</param>
        /// <returns>
        /// true if unit was merged.
        /// false otherwise
        /// </returns>
        bool Merge(IUndoUnit unit);
 
        #endregion Public Methods        
 
        //------------------------------------------------------
        //
        //  Public Properties
        //
        //------------------------------------------------------
 
        //------------------------------------------------------
        //
        //  Public Events
        //
        //------------------------------------------------------
 
        //------------------------------------------------------
        //
        //  Protected Methods
        //
        //------------------------------------------------------
 
        //------------------------------------------------------
        //
        //  Protected Properties
        //
        //------------------------------------------------------
 
        //------------------------------------------------------
        //
        //  Internal Methods
        //
        //------------------------------------------------------
 
        //------------------------------------------------------
        //
        //  Internal Properties
        //
        //------------------------------------------------------
 
        //------------------------------------------------------
        //
        //  Internal Events
        //
        //------------------------------------------------------
 
        //------------------------------------------------------
        //
        //  Private Methods
        //
        //------------------------------------------------------
 
        //------------------------------------------------------
        //
        //  Private Properties
        //
        //------------------------------------------------------
 
        //------------------------------------------------------
        //
        //  Private Fields
        //
        //------------------------------------------------------
 
    }
}