/Lyrics/Lyrics.App/WPH/WPH/Utils/AppErrorList.cs

using System;

using System.Collections;

using System.Linq;



namespace WPH.Utils

{

	/// <summary>

	/// AppErrorList is a collection of <see cref="AppError">AppError</see> objects.

	/// The AppErrorList is useful when you have a batch process that may trigger

	/// a number of exceptions or business rule violations, and you would prefer to 

	/// gather the complete list of errors before returning information to the user,

	/// as opposed to stopping at the first error.  Input validation is an example 

	/// situation when this might be used. 

	/// <seealso cref="AppError"/>

	/// <seealso cref="AppErrorFilter"/>

	/// <seealso cref="IErrorProvider"/>

	/// </summary>

	/// <remarks>

	/// For convenience, the <see cref="WPH.Utils.AppErrorList.Add(string, string)">Add</see> method is overloaded to take 

	/// the same parameters as the <see cref="AppError">AppError</see> constructors,

	/// so it is not necessary to build the AppError is a separate call.  

	/// <para>In imitation of the <see cref="ArrayList">ArrayList</see> class, AppErrorList

	/// has an <see cref="WPH.Utils.AppErrorList.AddRange">AddRange</see> method that will apppend another

	/// AppErrorList to the current instance.</para>

	/// </remarks>

	[Serializable]

	public class AppErrorList : CollectionBase

	{

		/// <summary>

		/// Defines the protected Type _containedType as a "WPH.Utils.AppError" type.

		/// </summary>

		protected Type _containedType = Type.GetType("WPH.Utils.AppError");



		#region Extensions



		/// <summary>

		/// Creates a new <see cref="AppError">AppError</see> instance and adds it to the collection.

		/// </summary>

		/// <param name="errorId"></param>

		/// <param name="errorMessage"></param>

		/// <returns></returns>

		public int Add(string errorId, string errorMessage)

		{

			return Add( new AppError(errorId, errorMessage) );

		}

		

		/// <summary>

		/// Creates a new <see cref="AppError">AppError</see> instance and adds it to the collection.

		/// </summary>

		/// <param name="errorId"></param>

		/// <param name="errorMessage"></param>

		/// <param name="severity"></param>

		/// <returns></returns>

		public int Add(string errorId, string errorMessage, ErrorSeverity severity)

		{

			return Add( new AppError(errorId, errorMessage, severity) );

		}

		

		/// <summary>

		/// Creates a new <see cref="AppError">AppError</see> instance and adds it to the collection.

		/// </summary>

		/// <param name="ex"></param>

		/// <returns></returns>

		public int Add(Exception ex)

		{

			int retval = Add( new AppError(ex) );

			

			if(ex.InnerException != null)

			{   Add(ex.InnerException); // Recursive...

			}

			

			return retval;

		}

		

		/// <summary>

		/// Appends the elements of another AppErrorList to this instance.

		/// </summary>

		/// <param name="list"></param>

		public void AddRange(AppErrorList list)

		{

			InnerList.AddRange(list);

		}

		

		/// <summary>

		/// Returns true if the collection has an error whose severity equals or exceeds

		/// the given ErrorSeverity value. 

		/// </summary>

		/// <param name="severity"></param>

		/// <returns></returns>

		public bool ContainsSeverity(ErrorSeverity severity)

		{

			var sev = (int) severity;



			return this.Cast<AppError>().Any(err => (int) err.Severity >= sev);

			/*

			foreach( AppError err in this ) {

				if( (int)err.Severity >= sev ) { return true; }

			}

			*/

		}

		

		/// <summary>

		/// Returns the combined output of each AppError item's ToString() method,

		/// joined with newline characters.

		/// </summary>

		/// <returns></returns>

		public override string ToString() {

			return ToString("G");

		}



		/// <summary>

		/// Overloads the ToString override method which returns the AppError item's ToString() method.

		/// "G" or no parameter at all returns the entire AppError item's set of information.

		/// "M" returns only the error messages.

		/// </summary>

		/// <param name="fmt"></param>

		/// <returns></returns>

		public string ToString(string fmt)

		{

			var buf = new System.Text.StringBuilder(InnerList.Count * 200);

			foreach(AppError err in this)

			{	

				switch (fmt.ToUpper()) {

					case "G" :

						buf.Append(err.ToString());

						break;

					case "M" :

						buf.Append(err.Message);

						break;

					default :

						buf.Append(err.ToString());

						break;

				}

				buf.Append("\r\n");

			}

			return buf.ToString();

		}

		

        #endregion

	

		#region CollectionBase method overrides



		/// <summary>

		/// Adds the specified value.

		/// </summary>

		/// <param name="value">The value.</param>

		/// <returns></returns>

		public int Add(AppError value)

		{

			return List.Add(value);

		}



		/// <summary>

		/// Determines whether [contains] [the specified value].

		/// </summary>

		/// <param name="value">The value.</param>

		/// <returns>

		/// 	<c>true</c> if [contains] [the specified value]; otherwise, <c>false</c>.

		/// </returns>

		public bool Contains(AppError value)

		{

			return List.Contains(value);

		}



		/// <summary>

		/// Indexes the of.

		/// </summary>

		/// <param name="value">The value.</param>

		/// <returns></returns>

		public int IndexOf(AppError value)

		{

			return List.IndexOf(value);

		}



		/// <summary>

		/// Inserts the specified index.

		/// </summary>

		/// <param name="index">The index.</param>

		/// <param name="value">The value.</param>

		public void Insert(int index, AppError value)

		{

			List.Insert(index, value);

		}



		/// <summary>

		/// Removes the specified value.

		/// </summary>

		/// <param name="value">The value.</param>

		public void Remove(AppError value)

		{

			List.Remove(value);

		}



		/// <summary>

		/// Gets or sets the <see cref="WPH.Utils.AppError"/> at the specified index.

		/// </summary>

		/// <value></value>

		public AppError this[int index]

		{

			get { return (AppError)List[index]; }

			set { List[index] = value; }

		}



		/// <summary>

		/// Performs additional custom processes before inserting a new element into the <see cref="T:System.Collections.CollectionBase"></see> instance.

		/// </summary>

		/// <param name="index">The zero-based index at which to insert value.</param>

		/// <param name="value">The new value of the element at index.</param>

		protected override void OnInsert(int index, object value)

		{

			base.OnInsert (index, value);

			

			if( (value as AppError) == null )

				throw new ArgumentException("value must be of type AppError.", "value");

		}



		/// <summary>

		/// Performs additional custom processes when removing an element from the <see cref="T:System.Collections.CollectionBase"></see> instance.

		/// </summary>

		/// <param name="index">The zero-based index at which value can be found.</param>

		/// <param name="value">The value of the element to remove from index.</param>

		protected override void OnRemove(int index, object value)

		{

			base.OnRemove (index, value);

			

			if( (value as AppError) == null )

				throw new ArgumentException("value must be of type AppError.", "value");

		}



		/// <summary>

		/// Performs additional custom processes before setting a value in the <see cref="T:System.Collections.CollectionBase"></see> instance.

		/// </summary>

		/// <param name="index">The zero-based index at which oldValue can be found.</param>

		/// <param name="oldValue">The value to replace with newValue.</param>

		/// <param name="newValue">The new value of the element at index.</param>

		protected override void OnSet(int index, object oldValue, object newValue)

		{

			base.OnSet (index, oldValue, newValue);

			

			if( (newValue as AppError) == null )

				throw new ArgumentException("newValue must be of type AppError.", "newValue");

		}



		/// <summary>

		/// Performs additional custom processes when validating a value.

		/// </summary>

		/// <param name="value">The object to validate.</param>

		protected override void OnValidate(object value)

		{

			base.OnValidate (value);

			

			if( (value as AppError) == null )

				throw new ArgumentException("value must be of type AppError.", "value");

		}

		

		#endregion



		/// <summary>

		/// Returns an enumerator that iterates through the <see cref="T:System.Collections.CollectionBase"></see> instance.

		/// </summary>

		/// <returns>

		/// An <see cref="T:System.Collections.IEnumerator"></see> for the <see cref="T:System.Collections.CollectionBase"></see> instance.

		/// </returns>

		public new IEnumerator GetEnumerator()

		{

			return new AppErrorListEnumerator(this);

		}

		



		#region inner class AppErrorListEnumerator

		

		/// <summary>

		/// Inter-class Enumerator for the AppErrorList object

		/// </summary>

		class AppErrorListEnumerator : IEnumerator

		{

			private int          _index = -1;

			private readonly AppErrorList _list;



			/// <summary>

			/// Initializes a new instance of the <see cref="AppErrorListEnumerator"/> class.

			/// </summary>

			/// <param name="list">The list.</param>

			public AppErrorListEnumerator(AppErrorList list)

			{

				_list = list;	

			}

			

			#region IEnumerator Members



			/// <summary>

			/// Sets the enumerator to its initial position, which is before the first element in the collection.

			/// </summary>

			/// <exception cref="T:System.InvalidOperationException">The collection was modified after the enumerator was created. </exception>

			public void Reset()

			{

				_index = -1;

			}



			/// <summary>

			/// Gets the current element in the collection.

			/// </summary>

			/// <value></value>

			/// <returns>The current element in the collection.</returns>

			/// <exception cref="T:System.InvalidOperationException">The enumerator is positioned before the first element of the collection or after the last element. </exception>

			public object Current

			{

				get 

				{ 

					if( _index == -1 )

						throw new InvalidOperationException();

			

					return _list[_index]; 

				}

			}



			/// <summary>

			/// Advances the enumerator to the next element of the collection.

			/// </summary>

			/// <returns>

			/// true if the enumerator was successfully advanced to the next element; false if the enumerator has passed the end of the collection.

			/// </returns>

			/// <exception cref="T:System.InvalidOperationException">The collection was modified after the enumerator was created. </exception>

			public bool MoveNext()

			{

				_index++;



				if (_index < _list.Count) {

					return true;

				}

				Reset();

				return false;

			}



			#endregion

		}

		

		#endregion

	}

}