Question

To recap for those .NET gurus who might not know the Java API:

ConcurrentHashMap in Java has atomic methods (i.e. require no external locking) for common Map modification operations such as:

putIfAbsent(K key, V value) remove(Object key, Object value) replace(K key, V value) 

It also allows iteration over the keyset without locking (it takes a copy at the start of iteration) and get() operations can generally be interleaved with calls to put() without blocking (it uses fine grained lock striping IIRC).

Anyway, my question is: does .NET have an equivalent Dictionary implementation?

I guess more generally, I’d be keen to know if .NET has a more general set of thread safe collection libraries. Or concurrency utilities in general – equivalent to Doug Lea‘s java.util.concurrent libraries.

Answer 1

Not that I know of. The closest thing to what you’re looking for would probably be the Synchronized method of the Hashtable, which returns a (sort of) thread-safe wrapper around the hashtable. It’s only thread-safe for multiple writers or multiple readers, though. If I recall correctly, a mixture of writers and readers will not be thread-safe.