Web User Forms for ASP.NET

// -- FILE ------------------------------------------------------------------
// name       : IVariableSet.cs
// project    : Itenso Web User Forms
// created    : Jani Giannoudis - 2008.10.30
// language   : c#
// environment: .NET 2.0
// copyright  : (c) 2008-2012 by Itenso GmbH, Switzerland
// --------------------------------------------------------------------------
using System;
using System.Text;
using System.Reflection;
using System.Globalization;
using System.Collections.Generic;

namespace Itenso.WebUserForms.Data.Variable
{

	// ------------------------------------------------------------------------
	public enum ObjectMappingMode
	{
		AnyValue,
		DefinedValue,
	} // enum ObjectMappingMode

	// ------------------------------------------------------------------------
	public sealed class VariableSet : IVariableSet
	{

		// ----------------------------------------------------------------------
		public int Count
		{
			get { return contentMap.Count; }
		} // Count

		// ----------------------------------------------------------------------
		public IEnumerable<string> VariableNames
		{
			get { return contentMap.Keys; }
		} // VariableNames

		// ----------------------------------------------------------------------
		public string this[ string variableName ]
		{
			get { return contentMap[ variableName ]; }
		} // this[]

		// ----------------------------------------------------------------------
		public string GetVariableContent( string variableName )
		{
			return contentMap.ContainsKey( variableName ) ? contentMap[ variableName ] : null;
		} // GetVariableContent

		// ----------------------------------------------------------------------
		public void MapContentToVariable( string variableName, string content )
		{
			if ( string.IsNullOrEmpty( variableName ) )
			{
				throw new ArgumentNullException( "variableName" );
			}
			if ( content == null )
			{
				throw new ArgumentNullException( "content" );
			}

			if ( contentMap.ContainsKey( variableName ) )
			{
				contentMap[ variableName ] = content;
			}
			else
			{
				contentMap.Add( variableName, content );
			}
		} // MapContentToVariable

		// ----------------------------------------------------------------------
		public void MapObjectPropertiesToVariables( object variableObject )
		{
			MapObjectPropertiesToVariables( variableObject, ObjectMappingMode.AnyValue );
		} // MapObjectPropertiesToVariables

		// ----------------------------------------------------------------------
		public void MapObjectPropertiesToVariables( object variableObject, ObjectMappingMode objectMappingMode )
		{
			if ( variableObject == null )
			{
				throw new ArgumentNullException( "variableObject" );
			}

			PropertyInfo[] propertyInfos = variableObject.GetType().GetProperties(
				BindingFlags.Instance | BindingFlags.Public | BindingFlags.NonPublic );
			foreach ( PropertyInfo propertyInfo in propertyInfos )
			{
				if ( propertyInfo.PropertyType.BaseType == null )
				{
					continue; // do not allow classes and interfaces
				}

				object variableValue = propertyInfo.GetValue( variableObject, null );
				if ( objectMappingMode == ObjectMappingMode.DefinedValue && variableValue == null )
				{
					continue;
				}

				if ( variableValue == null )
				{
					variableValue = string.Empty;
				}
				MapContentToVariable( propertyInfo.Name, variableValue.ToString() );
			}
		} // MapObjectPropertiesToVariables

		// ----------------------------------------------------------------------
		public void RemoveVariable( string variableName )
		{
			if ( string.IsNullOrEmpty( variableName ) )
			{
				throw new ArgumentNullException( "variableName" );
			}
			contentMap.Remove( variableName );
		} // RemoveVariable

		// ----------------------------------------------------------------------
		public string Expand( string textToExpand )
		{
			StringBuilder output = new StringBuilder();
			ExpandVariablesRecursive( textToExpand, startDelimiter, endDelimiter, new Stack<string>(), output );
			return output.ToString();
		} // Expand

		// ----------------------------------------------------------------------
		public void Clear()
		{
			contentMap.Clear();
		} // Clear

		// ----------------------------------------------------------------------
		public void CopyTo( IVariableSet destination )
		{
			CopyTo( destination, null );
		} // CopyTo

		// ----------------------------------------------------------------------
		public void CopyTo( IVariableSet destination, string nameFormat )
		{
			if ( destination == null )
			{
				throw new ArgumentNullException( "destination" );
			}

			foreach ( string variableName in VariableNames )
			{
				string destinationVariableName = variableName;
				if ( !string.IsNullOrEmpty( nameFormat ) )
				{
					destinationVariableName = string.Format(
						CultureInfo.InvariantCulture,
						nameFormat,
						destinationVariableName );
				}
				destination.MapContentToVariable( destinationVariableName, this[ variableName ] );
			}
		} // CopyTo

		// ----------------------------------------------------------------------
		private void ExpandVariablesRecursive(
			string textToExpand,
			string variablePrefix,
			string variablePostfix,
			Stack<string> replacementStack,
			StringBuilder output
		)
		{
			if ( !string.IsNullOrEmpty( textToExpand ) )
			{
				int remainderBegin = 0;
				int totalLen = textToExpand.Length;
				int varPrefixLen = variablePrefix.Length;
				int varStartPos = textToExpand.IndexOf( variablePrefix, StringComparison.Ordinal );
				while ( varStartPos >= remainderBegin )
				{
					if ( remainderBegin < varStartPos )
					{
						output.Append( textToExpand.Substring( remainderBegin, varStartPos - remainderBegin ) );
						remainderBegin = varStartPos;
					}
					int varNameBegin = varStartPos + varPrefixLen;
					int varEndPos = textToExpand.IndexOf( variablePostfix, varNameBegin, StringComparison.Ordinal );
					int nextSearchBegin = varEndPos + variablePostfix.Length;
					if ( varEndPos >= varNameBegin )
					{
						int varNameLen = varEndPos - varNameBegin;
						string variableName = textToExpand.Substring( varNameBegin, varNameLen );
						string replacement = GetVariableContent( variableName );
						if ( replacement != null )
						{
							if ( replacementStack.Contains( variableName ) )
							{
							}
							else
							{
								replacementStack.Push( variableName );
								ExpandVariablesRecursive( replacement, variablePrefix, variablePostfix, replacementStack, output );
								replacementStack.Pop();
								remainderBegin = nextSearchBegin;
							}
						}
						else
						{
							nextSearchBegin = varStartPos + 1;
						}
					}
					else
					{
						break;
					}
					varStartPos = textToExpand.IndexOf( variablePrefix, nextSearchBegin, StringComparison.Ordinal );
				}
				if ( remainderBegin < totalLen )
				{
					output.Append( textToExpand.Substring( remainderBegin ) );
				}
			}
		} // ExpandVariablesRecursive

		// ----------------------------------------------------------------------
		// members
		private readonly SortedDictionary<string, string> contentMap = new SortedDictionary<string, string>();

		private const string startDelimiter = "${";
		private const string endDelimiter = "}";

	} // class VariableSet

} // namespace Itenso.WebUserForms.Data.Variable
// -- EOF -------------------------------------------------------------------