Async Operations

As another addition of Hazelcast ICache over the normal JCache specification, Hazelcast provides asynchronous versions of almost all methods, returning a com.hazelcast.core.ICompletableFuture. By using these methods and the returned future objects, you can use JCache in a reactive way by registering zero or more callbacks on the future to prevent blocking the current thread.

Name of the asynchronous versions of the methods append the phrase Async to the method name. Sample code is shown below using the method putAsync().

ICache<Integer, String> unwrappedCache = cache.unwrap( ICache.class );
ICompletableFuture<String> future = unwrappedCache.putAsync( 1, "value" );
future.andThen( new ExecutionCallback<String>() {
  public void onResponse( String response ) {
    System.out.println( "Previous value: " + response );

  public void onFailure( Throwable t ) {
} );

Following methods are available in asynchronous versions:

  • get(key):
    • getAsync(key)
    • getAsync(key, expiryPolicy)
  • put(key, value):
    • putAsync(key, value)
    • putAsync(key, value, expiryPolicy)
  • putIfAbsent(key, value):
    • putIfAbsentAsync(key, value)
    • putIfAbsentAsync(key, value, expiryPolicy)
  • getAndPut(key, value):
    • getAndPutAsync(key, value)
    • getAndPutAsync(key, value, expiryPolicy)
  • remove(key):
    • removeAsync(key)
  • remove(key, value):
    • removeAsync(key, value)
  • getAndRemove(key):
    • getAndRemoveAsync(key)
  • replace(key, value):
    • replaceAsync(key, value)
    • replaceAsync(key, value, expiryPolicy)
  • replace(key, oldValue, newValue):
    • replaceAsync(key, oldValue, newValue)
    • replaceAsync(key, oldValue, newValue, expiryPolicy)
  • getAndReplace(key, value):
    • getAndReplaceAsync(key, value)
    • getAndReplaceAsync(key, value, expiryPolicy)

The methods with a given javax.cache.expiry.ExpiryPolicy are further discussed in the Custom ExpiryPolicy section.

image NOTE: Asynchronous versions of the methods are not compatible with synchronous events.