By default the map allows immutable keys and values. Custom keys and values should implement \io\vertx\jphp\core\shareddata\io.vertx.core.shareddata.Shareable interface. The map returns their copies.

This ensures there is no shared access to mutable state from different threads (e.g. different event loops) in the Vert.x instance, and means you don't have to protect access to that state using synchronization or locks.

Since the version 3.4, this class extends the interface. However some methods are only accessible in Java.

When the lock is obtained, no-one else in the cluster can obtain the lock with the same name until the lock is released.

Shared data provides:

• synchronous shared maps (local)
• asynchronous maps (local or cluster-wide)
• asynchronous locks (local or cluster-wide)
• asynchronous counters (local or cluster-wide)

WARNING: In clustered mode, asynchronous maps/locks/counters rely on distributed data structures provided by the cluster manager. Beware that the latency relative to asynchronous maps/locks/counters operations can be much higher in clustered than in local mode.