source: branches/PersistenceOverhaul/HeuristicLab.ExtLibs/HeuristicLab.NRefactory/5.5.0/NRefactory-5.5.0/Utils/EmptyList.cs

// Copyright (c) 2010-2013 AlphaSierraPapa for the SharpDevelop Team
// 
// Permission is hereby granted, free of charge, to any person obtaining a copy of this
// software and associated documentation files (the "Software"), to deal in the Software
// without restriction, including without limitation the rights to use, copy, modify, merge,
// publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons
// to whom the Software is furnished to do so, subject to the following conditions:
// 
// The above copyright notice and this permission notice shall be included in all copies or
// substantial portions of the Software.
// 
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED,
// INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR
// PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE
// FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR
// OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
// DEALINGS IN THE SOFTWARE.

using System;
using System.Collections;
using System.Collections.Generic;
using System.Collections.ObjectModel;

namespace ICSharpCode.NRefactory
{
  [Serializable]
  public sealed class EmptyList<T> : IList<T>, IEnumerator<T>
    #if NET_4_5
    , IReadOnlyList<T>
    #endif
  {
    public static readonly EmptyList<T> Instance = new EmptyList<T>();
    
    private EmptyList() {}
    
    public T this[int index] {
      get { throw new ArgumentOutOfRangeException("index"); }
      set { throw new ArgumentOutOfRangeException("index"); }
    }
    
    public int Count {
      get { return 0; }
    }
    
    bool ICollection<T>.IsReadOnly {
      get { return true; }
    }
    
    int IList<T>.IndexOf(T item)
    {
      return -1;
    }
    
    void IList<T>.Insert(int index, T item)
    {
      throw new NotSupportedException();
    }
    
    void IList<T>.RemoveAt(int index)
    {
      throw new NotSupportedException();
    }
    
    void ICollection<T>.Add(T item)
    {
      throw new NotSupportedException();
    }
    
    void ICollection<T>.Clear()
    {
    }
    
    bool ICollection<T>.Contains(T item)
    {
      return false;
    }
    
    void ICollection<T>.CopyTo(T[] array, int arrayIndex)
    {
    }
    
    bool ICollection<T>.Remove(T item)
    {
      return false;
    }
    
    IEnumerator<T> IEnumerable<T>.GetEnumerator()
    {
      return this;
    }
    
    System.Collections.IEnumerator System.Collections.IEnumerable.GetEnumerator()
    {
      return this;
    }
    
    T IEnumerator<T>.Current {
      get { return default(T); }
    }
    
    object IEnumerator.Current {
      get { return default(T); }
    }
    
    void IDisposable.Dispose()
    {
    }
    
    bool IEnumerator.MoveNext()
    {
      return false;
    }
    
    void IEnumerator.Reset()
    {
    }
  }
}