115 lines
4.3 KiB
C#
115 lines
4.3 KiB
C#
#region Apache License 2.0
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/*
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Nuclex .NET Framework
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Copyright (C) 2002-2024 Markus Ewald / Nuclex Development Labs
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Licensed under the Apache License, Version 2.0 (the "License");
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you may not use this file except in compliance with the License.
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You may obtain a copy of the License at
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http://www.apache.org/licenses/LICENSE-2.0
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Unless required by applicable law or agreed to in writing, software
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distributed under the License is distributed on an "AS IS" BASIS,
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WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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See the License for the specific language governing permissions and
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limitations under the License.
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*/
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#endregion // Apache License 2.0
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using System;
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using System.Collections.ObjectModel;
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namespace Nuclex.Support.Collections {
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/// <summary>Collection that automatically assigns an owner to all its elements</summary>
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/// <remarks>
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/// This collection automatically assigns a parent object to elements that
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/// are managed in it. The elements have to derive from the Parentable<>
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/// base class.
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/// </remarks>
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/// <typeparam name="TParent">Type of the parent object to assign to items</typeparam>
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/// <typeparam name="TItem">Type of the items being managed in the collection</typeparam>
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public class ParentingCollection<TParent, TItem> : Collection<TItem>
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where TItem : Parentable<TParent> {
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/// <summary>Reparents all elements in the collection</summary>
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/// <param name="parent">New parent to take ownership of the items</param>
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protected void Reparent(TParent parent) {
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this.parent = parent;
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for(int index = 0; index < Count; ++index)
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base[index].SetParent(parent);
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}
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/// <summary>Clears all elements from the collection</summary>
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protected override void ClearItems() {
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for(int index = 0; index < Count; ++index)
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base[index].SetParent(default(TParent));
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base.ClearItems();
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}
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/// <summary>Inserts a new element into the collection</summary>
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/// <param name="index">Index at which to insert the element</param>
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/// <param name="item">Item to be inserted</param>
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protected override void InsertItem(int index, TItem item) {
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base.InsertItem(index, item);
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item.SetParent(this.parent);
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}
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/// <summary>Removes an element from the collection</summary>
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/// <param name="index">Index of the element to remove</param>
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protected override void RemoveItem(int index) {
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base[index].SetParent(default(TParent));
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base.RemoveItem(index);
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}
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/// <summary>Takes over a new element that is directly assigned</summary>
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/// <param name="index">Index of the element that was assigned</param>
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/// <param name="item">New item</param>
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protected override void SetItem(int index, TItem item) {
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base[index].SetParent(default(TParent));
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base.SetItem(index, item);
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item.SetParent(this.parent);
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}
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/// <summary>Disposes all items contained in the collection</summary>
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/// <remarks>
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/// <para>
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/// This method is intended to support collections that need to dispose their
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/// items. It will unparent all of the collection's items and call Dispose()
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/// on any item that implements IDisposable.
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/// </para>
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/// <para>
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/// Do not call this method from your destructor as it will access the
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/// contained items in order to unparent and to Dispose() them, which leads
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/// to undefined behavior since the object might have already been collected
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/// by the GC. Call it only if your object is being manually disposed.
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/// </para>
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/// </remarks>
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protected void DisposeItems() {
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// Dispose all the items in the collection that implement IDisposable,
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// starting from the last item in the assumption that this is the fastest
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// way to empty a list without causing excessive shiftings in the array.
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for(int index = base.Count - 1; index >= 0; --index) {
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IDisposable disposable = base[index] as IDisposable;
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// If the item is disposable, destroy it now
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if(disposable != null) {
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disposable.Dispose();
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}
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}
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base.ClearItems();
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}
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/// <summary>Parent this collection currently belongs to</summary>
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private TParent parent;
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}
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} // namespace Nuclex.Support.Collections
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