If you just have to read properties on the return object, you may try
treating it as JSONObject.
Alternatively you could call a method of your Java object in the resolver function of the promise to check conditions to decide if you want to resolve/reject.
p.then() could be called with onFulfilled/onRejected functions just wrapping Java method calls to handle the result.
Example:
public class PromiseWrapper {
boolean evaluate(String value) {
return value != null ? true : false;
}
void onFulfilled(String value) {
// use value
}
void onRejected(Strin reason) {
// use reason
}
public native void doSomethingAynchronously() /*-{
var p = new Promise(
function(resolve, reject) {
var value = null; // Get value from somewhere
if([email protected]::evaluate(Ljava/lang/String;)(value)) {
resolve(value);
}
else {
reject("Because");
}
}
);
p.then(function(value) {
[email protected]::onFulfilled(Ljava/lang/String;)(value);
},
function(reason) {
[email protected]::onRejected(Ljava/lang/String;)(reason);
}
);
}-*/;
}
This is an untested example.