循环,直到RxJava中的条件变为真
我希望我的代码重复某个异步操作,直到该操作成功(即,直到返回循环,直到RxJava中的条件变为真,java,rx-java,Java,Rx Java,我希望我的代码重复某个异步操作,直到该操作成功(即,直到返回true) 目前,我正在使用以下解决方法: Supplier<Observable<Boolean>> myOperation = () -> { // do something useful and return 'true' if it was successful // NOTE: GENERATING A RANDOM NUMBER IS JUST AN EXAMPLE HERE //
true
)
目前,我正在使用以下解决方法:
Supplier<Observable<Boolean>> myOperation = () -> {
// do something useful and return 'true' if it was successful
// NOTE: GENERATING A RANDOM NUMBER IS JUST AN EXAMPLE HERE
// I WANT TO RUN AN ASYNCHRONOUS OPERATION (LIKE PINGING A SERVER
// OR THE LIKE) AND RETRY IT UNTIL IT SUCCEEDS.
System.out.println("Try");
return Observable.just(Math.random() > 0.9);
};
final Throwable retry = new IllegalStateException();
Observable.<Boolean>create(subscriber -> {
myOperation.get().subscribe(subscriber);
}).flatMap(b -> b ? Observable.just(b) : Observable.error(retry))
.retryWhen(exceptions -> exceptions.flatMap(exception -> {
if (exception == retry) {
return Observable.timer(1, TimeUnit.SECONDS);
}
return Observable.error(exception);
}))
.toBlocking()
.forEach(b -> {
System.out.println("Connected.");
});
代码符合我的要求,但看起来不太优雅。我相信一定有更好的办法。可能通过使用自定义的运算符
有人知道如何在RxJava中实现同样的功能,但要以更可读的方式实现,而且不需要人工的可丢弃的?时间不够,所以这将是通过内存实现的
public class Randomizer implements Iterable<Double>, Iterator<Double> {
public Iterator<Double> getIterator() {return this;}
public boolean hasNext() {return true;}
public Double next() {return Math.random();}
}
...
Observable.from(new Randomizer())
.takeWhile(value -> value < 0.99);
// or takeUntil(value -> value > 0.99); can't remember their differences.
请记住,如果使用改型,则不需要延迟(),因为改型将在新订阅发生时重新启动呼叫。谢谢。我很难将你的解决方案映射到我的问题上。我想重试异步操作,直到它成功。生成随机数只是这里的一个例子。
public class Randomizer implements Iterable<Double>, Iterator<Double> {
public Iterator<Double> getIterator() {return this;}
public boolean hasNext() {return true;}
public Double next() {return Math.random();}
}
...
Observable.from(new Randomizer())
.takeWhile(value -> value < 0.99);
// or takeUntil(value -> value > 0.99); can't remember their differences.
Observable.defer(() -> createConnectionObservable())
.retry((count, err) -> {
if(count>9) return false;
if(!(err instanceof IOException)) return false;
return true;
})