Describes an object that acts as a proxy for a result that is initially unknown.
A Promise is returned as the result of a remote method invocation on a RemoteReference. Because remote method invocations are processed asynchronously (i.e. non blocking), a promise object is returned while awaiting for the return value. When this value is eventually returned, the Promise object is said to be resolved.
A Promise object accepts one or more PromiseListeners that are triggered when the promise is resolved.
Returns a string representation of a Promise object.
Install a PromiseListener to obtain the return value when the promise is resolved.
listener - used to trigger a callback method when the promise is resolved.
a string representation of the promise.