如何在PlayFrameworkJavaAPI中将可观察转换为承诺
我的默认承诺实现如下所示:如何在PlayFrameworkJavaAPI中将可观察转换为承诺,playframework,promise,reactive-programming,rx-java,Playframework,Promise,Reactive Programming,Rx Java,我的默认承诺实现如下所示: public F.Promise<Result> index() { return F.Promise.promise(() -> intensiveComputationSync()) .map(result -> ok(String.valueOf(result))); } public F.Promise index(){ 返回F.Promise.Promise(()->intensiveComputationSyn
public F.Promise<Result> index() {
return F.Promise.promise(() -> intensiveComputationSync())
.map(result -> ok(String.valueOf(result)));
}
public F.Promise index(){
返回F.Promise.Promise(()->intensiveComputationSync())
.map(结果->确定(字符串.valueOf(结果));
}
但现在我有了rx api:
private Observable<Integer> intensiveComputationObservable() {
return Observable.create(subscriber -> {
try {
subscriber.onNext(intensiveComputationSync());
} catch (Exception e) {
subscriber.onError(e);
}
subscriber.onCompleted();
});
}
私有可观察强度计算可观察(){
返回可观察。创建(订户->{
试一试{
subscriber.onNext(intensiveComputationSync());
}捕获(例外e){
认股人。认股人(e);
}
subscriber.onCompleted();
});
}
我如何在承诺中使用我的rx api?对正确的错误处理特别感兴趣。似乎我找到了解决方案 用承诺包装可观察的功能:
public static <T> F.Promise<T> observableToPromise(Observable<T> obs) {
scala.concurrent.Promise<T> scalaPromise = scala.concurrent.Promise$.MODULE$.<T>apply();
obs.subscribe(
result -> scalaPromise.success(result),
throwable -> scalaPromise.failure(throwable)
);
return F.Promise.wrap(scalaPromise.future());
}
公共静态F.承诺可观察承诺(可观察obs){
scala.concurrent.Promise scalaPromise=scala.concurrent.Promise$.MODULE$.apply();
订阅(
结果->缩放成功(结果),
可丢弃->缩放预览失败(可丢弃)
);
返回F.Promise.wrap(scalaPromise.future());
}
现在我的行动:
public F.Promise<Result> index() {
//convert observable to promise then map computation result to F.Promise<Result>
F.Promise<Result> succeedPromise =
observableToPromise(
//computation on another thread
intensiveComputationObservable().subscribeOn(Schedulers.newThread())
).map(result -> ok(String.valueOf(result)));
//if exception while computation thrown, we returns another status
return succeedPromise
.recoverWith(throwable -> F.Promise.pure(internalServerError("error")));
}
public F.Promise index(){
//将可观测值转换为promise,然后将计算结果映射到F.promise
承诺成功的承诺=
可观察的承诺(
//另一个线程上的计算
intensiveComputationObservable().subscribeOn(Schedulers.newThread())
).map(结果->确定(字符串.valueOf(结果));
//如果计算时抛出异常,则返回另一个状态
回报成功的承诺
.recoverWith(throwable->F.Promise.pure(internalServerError(“error”));
}
在游戏2.5中,有一种方法可以做到这一点:
public CompletableFuture<Result> callRPC() {
Observable<Object> result = <create observable>
CompletableFuture<Object> completableFuture = new CompletableFuture<>();
result.subscribe((active) -> completableFuture.complete(active),
(err) -> completableFuture.completeExceptionally(err));
return completableFuture.thenApply( i -> ok(Json.toJson(i)));
}
public CompletableFuture callRPC(){
可观察结果=
CompletableFuture CompletableFuture=新的CompletableFuture();
结果。订阅((活动)->completableFuture.complete(活动),
(err)->completableFuture.completeeexceptionaly(err));
返回completableFuture.thenApply(i->ok(Json.toJson(i));
}