java - spring async rest client orchestrate few calls -

i have following problem in service building object x in order build need make few http calls in order required data fill (each rest fills part of object.) in order keep performance high thought nice make call async , after calls done return object caller. looks this

listenablefuture<responseentity<string>> future1 = asyctemp.exchange(url, method, requestentity, responsetype); future1.addcallback({     //process response , set fields     complexobject.field1 = "parserd response" },{     //in case of fail fill default or take ather actions }) 

i don't know how wait features done. guess standard spring ways of solving kind of issue. in advance suggestions. spring version - 4.2.4.release best regards

adapted waiting callback multiple futures.

this example requests google , microsoft homepages. when response received in callback, , i've done processing, decrement countdownlatch. await countdownlatch, "blocking" current thread until countdownlatch reaches 0.

it's important decrement if call fails or succeeds, must hit 0 continue method!

public static void main(string[] args) throws exception {     string googleurl = "http://www.google.com";     string microsofturl = "http://www.microsoft.com";     asyncresttemplate asyncresttemplate = new asyncresttemplate();     listenablefuture<responseentity<string>> googlefuture = asyncresttemplate.exchange(googleurl, httpmethod.get, null, string.class);     listenablefuture<responseentity<string>> microsoftfuture = asyncresttemplate.exchange(microsofturl, httpmethod.get, null, string.class);     final countdownlatch countdownlatch = new countdownlatch(2);     listenablefuturecallback<responseentity<java.lang.string>> listenablefuturecallback = new listenablefuturecallback<responseentity<string>>() {          public void onsuccess(responseentity<string> stringresponseentity) {             system.out.println(string.format("[thread %d] status code: %d. body size: %d",                     thread.currentthread().getid(),                     stringresponseentity.getstatuscode().value(),                     stringresponseentity.getbody().length()             ));             countdownlatch.countdown();         }          public void onfailure(throwable throwable) {             system.err.println(throwable.getmessage());             countdownlatch.countdown();         }     };     googlefuture.addcallback(listenablefuturecallback);     microsoftfuture.addcallback(listenablefuturecallback);     system.out.println(string.format("[thread %d] line executed immediately.", thread.currentthread().getid()));     countdownlatch.await();     system.out.println(string.format("[thread %d] responses received.", thread.currentthread().getid()));  } 

the output console:

[thread 1] line executed immediately. [thread 14] status code: 200. body size: 112654 [thread 13] status code: 200. body size: 19087 [thread 1] responses received.