AbstractValueElement.cs

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// SmartAPI - .Net programmatic access to RedDot servers
//  
// Copyright (C) 2013 erminas GbR
// 
// This program is free software: you can redistribute it and/or modify it 
// under the terms of the GNU General Public License as published by the Free Software Foundation,
// either version 3 of the License, or (at your option) any later version.
// This program is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
// See the GNU General Public License for more details.
// 
// You should have received a copy of the GNU General Public License along with this program.
// If not, see <http://www.gnu.org/licenses/>.

using System;
using System.Web;
using System.Xml;
using erminas.SmartAPI.Exceptions;
using erminas.SmartAPI.Utils;

namespace erminas.SmartAPI.CMS.Project.Pages.Elements
{
    internal abstract class AbstractValueElement<T> : PageElement, IValueElement<T>
    {
        protected const string SAVE_VALUE =
            @"<ELEMENTS action=""save""><ELT guid=""{0}"" value=""{1}"" type=""{2}""></ELT></ELEMENTS>";

        protected T _value;

        protected AbstractValueElement(IProject project, Guid guid, ILanguageVariant languageVariant)
            : base(project, guid, languageVariant)
        {
        }

        protected AbstractValueElement(IProject project, XmlElement xmlElement) : base(project, xmlElement)
        {
            LoadXml();
        }

        public virtual void Commit()
        {
            //TODO bei null/"" SESSIONKEY setzen??
            string xmlNodeValue = GetXmlNodeValue();
            string htmlEncode = string.IsNullOrEmpty(xmlNodeValue)
                                    ? RQL.SESSIONKEY_PLACEHOLDER
                                    : HttpUtility.HtmlEncode(xmlNodeValue);
            ExecuteCommit(htmlEncode);
        }

        public void DeleteValue()
        {
            Value = default(T);
        }

        public void SetValueFromString(string value)
        {
            Value = string.IsNullOrEmpty(value) ? default(T) : FromString(value);
        }

        public virtual T Value
        {
            get { return LazyLoad(ref _value); }
            set { _value = value; }
        }

        protected void ExecuteCommit(string valueToSave)
        {
            using (new LanguageContext(LanguageVariant))
            {
                XmlDocument xmlDoc =
                    Project.ExecuteRQL(string.Format(SAVE_VALUE, Guid.ToRQLString(), valueToSave, (int) ElementType));
                if (xmlDoc.GetElementsByTagName("ELT").Count != 1 && !xmlDoc.InnerXml.Contains(Guid.ToRQLString()))
                {
                    throw new SmartAPIException(Session.ServerLogin,
                                                String.Format("Could not save element {0}", Guid.ToRQLString()));
                }
            }
        }

        protected abstract T FromString(string value);
        protected abstract T FromXmlNodeValue(string arg);

        protected virtual string GetXmlNodeValue()
        {
            return Equals(Value, null) ? null : Value.ToString();
        }

        protected override sealed void LoadWholePageElement()
        {
            LoadXml();
            LoadWholeValueElement();
        }

        protected abstract void LoadWholeValueElement();

        private void LoadXml()
        {
            InitIfPresent(ref _value, "value", FromXmlNodeValue);
        }
    }
}