Nuclex.Support/Source/Collections/ParentingCollection.cs

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#region CPL License
/*
Nuclex Framework
Copyright (C) 2002-2007 Nuclex Development Labs
This library is free software; you can redistribute it and/or
modify it under the terms of the IBM Common Public License as
published by the IBM Corporation; either version 1.0 of the
License, or (at your option) any later version.
This library is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
IBM Common Public License for more details.
You should have received a copy of the IBM Common Public
License along with this library
*/
#endregion
using System;
using System.Collections.Generic;
using System.Collections.ObjectModel;
using System.IO;
using System.Reflection;
namespace Nuclex.Support.Collections {
/// <summary>Collection that automatically assigns an owner to all its elements</summary>
/// <remarks>
/// This collection automatically assigns a parent object to elements that
/// are managed in it. The elements have to derive from the Parentable&lt;&gt;
/// base class.
/// </remarks>
/// <typeparam name="ParentType">Type of the parent object to assign to items</typeparam>
/// <typeparam name="ItemType">Type of the items being managed in the collection</typeparam>
public class ParentingCollection<ParentType, ItemType> : Collection<ItemType>
where ItemType : Parentable<ParentType> {
/// <summary>Reparents all elements in the collection</summary>
/// <param name="parent">New parent to take ownership of the items</param>
protected void Reparent(ParentType parent) {
this.parent = parent;
for(int index = 0; index < Count; ++index)
base[index].SetParent(parent);
}
/// <summary>Clears all elements from the collection</summary>
protected override void ClearItems() {
for(int index = 0; index < Count; ++index)
base[index].SetParent(default(ParentType));
base.ClearItems();
}
/// <summary>Inserts a new element into the collection</summary>
/// <param name="index">Index at which to insert the element</param>
/// <param name="item">Item to be inserted</param>
protected override void InsertItem(int index, ItemType item) {
base.InsertItem(index, item);
item.SetParent(this.parent);
}
/// <summary>Removes an element from the collection</summary>
/// <param name="index">Index of the element to remove</param>
protected override void RemoveItem(int index) {
base[index].SetParent(default(ParentType));
base.RemoveItem(index);
}
/// <summary>Takes over a new element that is directly assigned</summary>
/// <param name="index">Index of the element that was assigned</param>
/// <param name="item">New item</param>
protected override void SetItem(int index, ItemType item) {
base.SetItem(index, item);
item.SetParent(this.parent);
}
/// <summary>Disposes the collection and optionally all items contained therein</summary>
/// <param name="disposeItems">Whether to try calling Dispose() on all items</param>
/// <remarks>
/// <para>
/// This method is intended to support collections that need to dispose of their
/// items. The ParentingCollection will first detach all items from the parent
/// object and then call Dispose() on any item that implements IDisposable.
/// </para>
/// <para>
/// The items contained in the collection are not disconnected from their parent
/// (eg. Reparent()ed to null) because this is out of the scope for the
/// ParentingCollection&lt;&gt; class to decide and provokes the potentially
/// risky situation that an item, when it is Dispose()d, might try to disconnect
/// some events or perform other maintenance work on its parent object that
/// would then be no longer available. If you wish to disconnect the items from
/// their parent prior to disposing them, add a Reparent(null); call before the
/// line with InternalDispose(true); in your custom Dispose() method.
/// </para>
/// </remarks>
protected void InternalDispose(bool disposeItems) {
if(disposeItems) {
// Dispose of all the items in the collection that implement IDisposable
foreach(ItemType item in this) {
IDisposable disposable = item as IDisposable;
// If the item is disposable, we get rid of it
if(disposable != null)
disposable.Dispose();
}
}
// Remove all items from the collection
base.ClearItems();
}
/// <summary>Parent this collection currently belongs to</summary>
private ParentType parent;
}
} // namespace Nuclex.Support.Collections