A framework for comprehensive validation of user input

// Copyright (c) 2005 - 2012, Andreas Ganzer. All Rights reserved.

using System;
using System.Collections.Generic;
using System.Diagnostics;
using System.Globalization;
using System.Text;
using Ganzer.Properties;

namespace Ganzer.Validation
{
	//############################################################################
	/// <summary>
	/// The ListValidator class defines a validator that compares a string with
	/// a list of valid strings.
	/// </summary>
	/// 
	[Serializable]
	public class ListValidator : Validator
	{
		#region fields

		private bool __ignoreCase;
		private List<string> __valids;

		#endregion

		#region properties

		/// <summary>
		/// Gets/sets a value indicating whether the validation is case sensitive.
		/// </summary>
		/// 
		public bool IgnoreCase
		{
			get
			{
				return __ignoreCase;
			}
			set
			{
				__ignoreCase = value;
			}
		}

		/// <summary>
		/// Returns a collection that contains the valid texts.
		/// </summary>
		/// 
		public IList<string> ValidInputs
		{
			get
			{
				return __valids;
			}
		}

		#endregion

		#region ctor/dtor

		/// <summary>
		/// Creates a new instance of the validator.
		/// </summary>
		/// 
		/// <remarks>
		/// The options are set to <see cref="ValidatorOptions.AutoFill"/> and the
		/// list that contains the valid  strings is set to an empty list.
		/// <see cref="IgnoreCase"/> is set to <c>false</c>.
		/// </remarks>
		/// 
		public ListValidator()
			: base(ValidatorOptions.AutoFill)
		{
			__valids = new List<string>();
		}

		/// <summary>
		/// Initializes this object with the given arguments. The options are set to
		/// <see cref="ValidatorOptions.AutoFill"/> and the list that contains the
		/// valid  strings is set to an empty list.
		/// </summary>
		/// 
		/// <param name="ignoreCase">If this is <c>true</c>, the validated text is
		///   searched case insensitive, otherwise the validated text is searched case
		///   sensitive.</param>
		/// 
		public ListValidator( bool ignoreCase )
			: base(ValidatorOptions.AutoFill)
		{
			__ignoreCase = ignoreCase;
			__valids = new List<string>();
		}

		/// <summary>
		/// Initializes this object with the given arguments. The list that contains 
		/// the valid strings is set to an empty list.
		/// </summary>
		/// 
		/// <param name="ignoreCase">If this is <c>true</c>, the validated text is searched
		///   case insensitive, otherwise the validated text is searched case sensitive.</param>
		/// <param name="options">The options to set.</param>
		/// 
		public ListValidator( bool ignoreCase, ValidatorOptions options )
			: base(options)
		{
			__ignoreCase = ignoreCase;
			__valids = new List<string>();
		}

		/// <summary>
		/// Initializes this object with the given arguments. The options are set to
		/// <see cref="ValidatorOptions.AutoFill"/>.
		/// </summary>
		/// 
		/// <param name="valids">A list that contains valid strings.</param>
		/// <param name="ignoreCase">If this is <c>true</c>, the validated text is
		///   searched case insensitive, otherwise the validated text is searched case
		///   sensitive.</param>
		///   
		/// <exception cref="ArgumentNullException"><paramref name="valids"/> is <c>null</c>.</exception>
		/// 
		public ListValidator( IEnumerable<string> valids, bool ignoreCase )
			: base(ValidatorOptions.AutoFill)
		{
			Debug.Assert(valids != null);

			if( valids == null )
				throw new ArgumentNullException("valids");

			__ignoreCase = ignoreCase;
			__valids = new List<string>();
			__valids.AddRange(valids);
		}

		/// <summary>
		/// Initializes this object with the given arguments.
		/// </summary>
		/// 
		/// <param name="valids">A list that contains valid strings.</param>
		/// <param name="ignoreCase">If this is <c>true</c>, the validated text is
		///   searched case insensitive, otherwise the validated text is searched case
		///   sensitive.</param>
		/// <param name="options">The options to set.</param>
		/// 
		/// <exception cref="ArgumentNullException"><paramref name="valids"/> is <c>null</c>.</exception>
		/// 
		public ListValidator( IEnumerable<string> valids, bool ignoreCase, ValidatorOptions options )
			: base(options)
		{
			Debug.Assert(valids != null);

			if( valids == null )
				throw new ArgumentNullException("valids");

			__ignoreCase = ignoreCase;
			__valids = new List<string>();
			__valids.AddRange(valids);
		}

		#endregion

		#region methods

		/// <summary>
		/// Trys to find the given text in the list that contains the valid values.
		/// </summary>
		/// 
		/// <param name="text">The text to validate.</param>
		/// <param name="autoFill">If this is <c>true</c>, <paramref name="text"/> is
		///   filled up if possible. If this is <c>false</c>, the text is not filled up.
		///   This is independent of the option <see cref="ValidatorOptions.AutoFill"/>.</param>
		/// <param name="culture">Specifies the culture to use for interpreting the specified
		///   text.</param>
		///   
		/// <returns><c>true</c> if <paramref name="text"/> is valid.</returns>
		/// 
		protected override bool DoInputValidation( StringBuilder text, bool autoFill, CultureInfo culture )
		{
			if( !base.DoInputValidation(text, autoFill, culture) )
				return false;

			if( text.Length == 0 )
				return true;

			foreach( string s in __valids )
				if( string.Compare(text.ToString(), 0, s, 0, text.Length, IgnoreCase, culture) == 0 )
				{
					if( autoFill )
					{
						text.Length = 0;
						text.Append(s);
					}

					return true;
				}

			return false;
		}

		/// <summary>
		/// Validates the given text.
		/// </summary>
		/// 
		/// <param name="text">The text to validate.</param>
		/// <param name="culture">Specifies the culture to use for interpreting the specified
		///   text.</param>
		/// <param name="x">If the text is valid, this is set to <c>null</c>. Otherwise,
		///   this is set to a created <see cref="ValidatorException"/> instance.</param>
		/// 
		/// <returns><c>true</c> if <paramref name="text"/> is valid.</returns>
		/// 
		/// <remarks>
		/// If the option <see cref="ValidatorOptions.NeedsInput"/> is set, an empty
		/// text is applied to be invalid.
		/// </remarks>
		/// 
		protected override bool DoValidation( string text, CultureInfo culture, out ValidatorException x )
		{
			if( !base.DoValidation(text, culture, out x) )
				return false;

			if( text.Length == 0 )
				return true;

			foreach( string s in __valids )
				if( string.Compare(text, s, IgnoreCase, culture) == 0 )
					return true;

			x = new ValidatorException(String.IsNullOrEmpty(ErrorMessage) ? Resources.StrNotInList : ErrorMessage);

			return false;
		}

		#endregion
	}
}