C:/Private/OSS/n2cms/github/n2cms/src/Framework/N2/Collections/ItemFilter.cs

Go to the documentation of this file.

using System;
using System.Collections.Generic;
using System.Text;

namespace N2.Collections
{
        public abstract class ItemFilter : IPipeline, IDisposable
        {
                public abstract bool Match(ContentItem item);
                
                public virtual void Filter(IList<ContentItem> items)
                {
                        using (this)
                        {
                                for (int i = items.Count - 1; i >= 0; i--)
                                        if (!Match(items[i]))
                                                items.RemoveAt(i);
                        }
                }

        public virtual IEnumerable<T> Pipe<T>(IEnumerable<T> items)
            where T : ContentItem
        {
                        using (this)
                        {
                                foreach (T item in items)
                                        if (Match(item))
                                                yield return item;
                        }
        }

                public virtual IEnumerable<ContentItem> Pipe(IEnumerable<ContentItem> items)
                {
                        return Pipe<ContentItem>(items);
                }
        
                public static void Filter(IList<ContentItem> items, ItemFilter filter)
                {
                        filter.Filter(items);
        }

                #region IDisposable Members

                public virtual void Dispose()
                {
                        // do nothing
                }

                #endregion
        }
}