title: Lock on a key in a hazelcast cluster
body: <p>I am writing a distributed application using Hazelcast(JCache standard) for caching.</p>
  
  <p>I have an use case where I should put a lock on specific key in a cluster to prevent from calls during updating.</p>
  
  <ol>
  <li>thread1: get item1 for a config change(put a lock)</li>
  <li>thread2: get item1 for an update.</li>
  <li>thread2: put item1 with update and a new timestamp.</li>
  <li>thread1: put item1 with an old value and timestamp</li>
  </ol>
  
  <p>I know EhCache has something very similar, it's called acquireReadLockOnKey(Object key). </p>
  
  <p>How can I achieve that kind of lock using JCache and/or Hazelcast?</p>