//******************************************************************************************************
//  ObjectState.cs - Gbtc
//
//  Copyright © 2012, Grid Protection Alliance.  All Rights Reserved.
//
//  Licensed to the Grid Protection Alliance (GPA) under one or more contributor license agreements. See
//  the NOTICE file distributed with this work for additional information regarding copyright ownership.
//  The GPA licenses this file to you under the Eclipse Public License -v 1.0 (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.opensource.org/licenses/eclipse-1.0.php
//
//  Unless agreed to in writing, the subject software distributed under the License is distributed on an
//  "AS-IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. Refer to the
//  License for the specific language governing permissions and limitations.
//
//  Code Modification History:
//  ----------------------------------------------------------------------------------------------------
//  05/23/2007 - Pinal C. Patel
//       Generated original version of source code.
//  09/09/2008 - J. Ritchie Carroll
//       Converted to C#.
//  11/05/2008 - Pinal C. Patel
//       Edited code comments.
//  09/14/2009 - Stephen C. Wills
//       Added new header and license agreement.
//  12/14/2012 - Starlynn Danyelle Gilliam
//       Modified Header.
//
//******************************************************************************************************

using System;

namespace GSF
{
    /// <summary>
    /// A serializable class that can be used to track the current and previous state of an object.
    /// </summary>
    /// <typeparam name="TState">Type of the state to track.</typeparam>
    [Serializable]
    public class ObjectState<TState>
    {
        #region [ Members ]

        // Fields
        private string m_objectName;
        private TState m_currentState;
        private TState m_previousState;

        #endregion

        #region [ Constructors ]

        /// <summary>
        /// Initializes a new instance of the <see cref="ObjectState{TState}"/> class.
        /// </summary>
        /// <param name="objectName">The text label for the object whose state is being tracked.</param>
        public ObjectState(string objectName)
            : this(objectName, default(TState))
        {
        }

        /// <summary>
        /// Initializes a new instance of the <see cref="ObjectState{TState}"/> class.
        /// </summary>
        /// <param name="objectName">The text label for the object whose state is being tracked.</param>
        /// <param name="currentState">The current state of the object.</param>
        public ObjectState(string objectName, TState currentState)
            : this(objectName, currentState, default(TState))
        {
        }

        /// <summary>
        /// Initializes a new instance of the <see cref="ObjectState{TState}"/> class.
        /// </summary>
        /// <param name="objectName">The text label for the object whose state is being tracked.</param>
        /// <param name="currentState">The current state of the object.</param>
        /// <param name="previousState">The previous state of the object.</param>
        public ObjectState(string objectName, TState currentState, TState previousState)
        {
            this.ObjectName = objectName;
            this.CurrentState = currentState;
            this.PreviousState = previousState;
        }

        #endregion

        #region [ Properties ]

        /// <summary>
        /// Gets or sets a text label for the object whose state is being tracked.
        /// </summary>
        /// <exception cref="ArgumentNullException">The value being assigned is a null or empty string.</exception>
        public string ObjectName
        {
            get
            {
                return m_objectName;
            }
            set
            {
                if (string.IsNullOrEmpty(value))
                    throw new ArgumentNullException("value");

                m_objectName = value;
            }
        }

        /// <summary>
        /// Gets or sets the current state of the object.
        /// </summary>
        public TState CurrentState
        {
            get
            {
                return m_currentState;
            }
            set
            {
                m_currentState = value;
            }
        }

        /// <summary>
        /// Gets or sets the previous state of the object.
        /// </summary>
        public TState PreviousState
        {
            get
            {
                return m_previousState;
            }
            set
            {
                m_previousState = value;
            }
        }

        #endregion
    }
}