Thread-safe HashSet with Guava Collections

Question

Like the title says, i would like to get a thread-safe HashSet using Guava Collections.
Are any available?

Answer 1

Google Collections had a factory method named Sets.newConcurrentHashSet() for a while.

Its implementation was similar to Chris's suggestion:

public static <E> Set<E> newConcurrentHashSet() {
  return newSetFromMap(new ConcurrentHashMap<E, Boolean>());
}

They had a newSetFromMap() method inside the com.google.common.collect.Sets class (written by Doug Lea with assistance from members of JCP JSR-166). That method was added to java.util.Collections in java 1.6.

It was withdrawn in Google Collections 1.0rc1, since there are plans to better support concurrent sets in Guava (more information here).

This post expands on the use of the "newSetFromMap" method to construct concurrent sets.

Answer 2

Set<K> set = Collections.newSetFromMap(new ConcurrentHashMap<K, Boolean>());

Answer 3

Java 8 introduces new way to create concurrent hash set - ConcurrentHashMap.newKeySet()

Set<K> set = ConcurrentHashMap.newKeySet();

It's shorter than wrapping in Collections.newSetFromMap

Answer 4

This would be the right answer, Using the Sets class from Guava. Anyway the answer from @crhis was good intended.

Sets.newSetFromMap(new ConcurrentHashMap<V, Boolean>());