【发布时间】：2011-05-17 10:56:21
【问题描述】：
我正在尝试本着 ConcurrentDictionary 的精神实现一个 ConcurrentHashSet， 采取的方法是使用内部支持 ConcurrentDictionary 并编写小型委托方法，这就是我得到的，但是我坚持使用集合理论方法，尤其是。我不确定我是否可以使用 foreach 并且仍然不会违反并发
public class ConcurrentHashSet<TElement> : ISet<TElement>
{
private readonly ConcurrentDictionary<TElement, object> _internal;
public ConcurrentHashSet(IEnumerable<TElement> elements = null)
{
_internal = new ConcurrentDictionary<TElement, object>();
if (elements != null)
UnionWith(elements);
}
public void UnionWith(IEnumerable<TElement> other)
{
if (other == null) throw new ArgumentNullException("other");
foreach (var otherElement in other)
Add(otherElement);
}
public void IntersectWith(IEnumerable<TElement> other)
{
throw new NotImplementedException();
}
public void ExceptWith(IEnumerable<TElement> other)
{
throw new NotImplementedException();
}
public void SymmetricExceptWith(IEnumerable<TElement> other)
{
throw new NotImplementedException();
}
public bool IsSubsetOf(IEnumerable<TElement> other)
{
throw new NotImplementedException();
}
public bool IsSupersetOf(IEnumerable<TElement> other)
{
throw new NotImplementedException();
}
public bool IsProperSupersetOf(IEnumerable<TElement> other)
{
throw new NotImplementedException();
}
public bool IsProperSubsetOf(IEnumerable<TElement> other)
{
throw new NotImplementedException();
}
public bool Overlaps(IEnumerable<TElement> other)
{
return other.Any(otherElement => _internal.ContainsKey(otherElement));
}
public bool SetEquals(IEnumerable<TElement> other)
{
int otherCount = 0;
int thisCount = Count;
foreach (var otherElement in other)
{
otherCount++;
if (!_internal.ContainsKey(otherElement))
return false;
}
return otherCount == thisCount;
}
public bool Add(TElement item)
{
return _internal.TryAdd(item, null);
}
public void Clear()
{
_internal.Clear();
}
// I am not sure here if that fullfills contract correctly
void ICollection<TElement>.Add(TElement item)
{
Add(item);
}
public bool Contains(TElement item)
{
return _internal.ContainsKey(item);
}
public void CopyTo(TElement[] array, int arrayIndex)
{
_internal.Keys.CopyTo(array, arrayIndex);
}
public bool Remove(TElement item)
{
object ignore;
return _internal.TryRemove(item, out ignore);
}
public int Count
{
get { return _internal.Count; }
}
public bool IsReadOnly
{
get { return false; }
}
public IEnumerator<TElement> GetEnumerator()
{
return _internal.Keys.GetEnumerator();
}
IEnumerator IEnumerable.GetEnumerator()
{
return GetEnumerator();
}
}
【问题讨论】：
-
尝试购买轻微的并发改进并丢弃 HashSet 的性能是没有意义的。
-
@Hans，我是否也失去了添加、删除、包含的性能？ , 另外我认为我可以在其他线程添加时轻松迭代 Set
标签： c# .net concurrency dictionary hashset