#region License

/*
 * Copyright © 2002-2008 the original author or authors.
 *
 * Licensed 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.
 */

#endregion

#region Imports

using System.Web.SessionState;
using System.Web.UI;

#endregion

namespace Spring.Web.UI
{
    /// <summary>
    /// <see cref="SessionModelPersistenceMedium"/> implements <see cref="HttpSessionState"/>-based storage for 
    /// UI model management.
    /// </summary>
    /// <author>Erich Eichinger</author>
    public class SessionModelPersistenceMedium : IModelPersistenceMedium
    {
        /// <summary>
        /// Load the model for the specified control context.
        /// </summary>
        /// <remarks>
        /// The key used for loading the model from the session dictionary is obtained by calling <see cref="GetKey"/>
        /// </remarks>
        /// <param name="context">the control context.</param>
        /// <returns>the model for the specified control context.</returns>
        /// <seealso cref="GetKey"/>
        public object LoadFromMedium(Control context)
        {
            return GetItem(context, GetKey(context));
        }

        /// <summary>
        /// Save the specified model object to session.
        /// </summary>
        /// <remarks>
        /// The key used for storing the model into the session dictionary is obtained by calling <see cref="GetKey"/>
        /// </remarks>
        /// <param name="context">the control context.</param>
        /// <param name="modelToSave">the model to save.</param>
        /// <seealso cref="GetKey"/>
        public void SaveToMedium(Control context, object modelToSave)
        {
            SetItem(context, GetKey(context), modelToSave); 
        }

        /// <summary>
        /// Create the key to be used for accessing the <see cref="HttpSessionState"/> dictionary.
        /// </summary>
        /// <param name="context"></param>
        /// <returns></returns>
        protected virtual string GetKey(Control context)
        {
            return context.Page.Request.CurrentExecutionFilePath + context.UniqueID + ".Model";
        }

        /// <summary>
        /// Abstracts session access for unit testing.
        /// </summary>
        protected virtual object GetItem(Control context, string key)
        {
            return context.Page.Session[key];
        }

        /// <summary>
        /// Abstracts session access for unit testing.
        /// </summary>
        protected virtual void SetItem(Control context, string key, object item)
        {
            context.Page.Session[key] = item;
        }
    }
}