java - Retry logic with CompletableFuture -

i need submit task in async framework i'm working on, need catch exceptions, , retry same task multiple times before "aborting".

the code i'm working is:

int retries = 0; public completablefuture<result> executeactionasync() {      // execute action async , future     completablefuture<result> f = executemycustomactionhere();      // if future completes exception:     f.exceptionally(ex -> {         retries++; // increment retry count         if (retries < max_retries)             return executeactionasync();  // <--- submit 1 more time          // abort null value         return null;     });      // return future         return f; } 

this doesn't compile because return type of lambda wrong: expects result, executeactionasync returns completablefuture<result>.

how can implement async retry logic?

i solved similar problem using guava-retrying library.

callable<result> callable = new callable<result>() {     public result call() throws exception {         return executemycustomactionhere();     } };  retryer<boolean> retryer = retryerbuilder.<result>newbuilder()         .retryifresult(predicates.<result>isnull())         .retryifexceptionoftype(ioexception.class)         .retryifruntimeexception()         .withstopstrategy(stopstrategies.stopafterattempt(max_retries))         .build();  completablefuture.supplyasync( () -> {     try {         retryer.call(callable);     } catch (retryexception e) {         e.printstacktrace();     } catch (executionexception e) {        e.printstacktrace();     } });