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Extend Future#compose to allow remapping errors - closes #3144

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Julien Viet
2019-10-02 22:23:50 +02:00
parent 9391ea39bd
commit 95f82b52bd
1 changed files with 34 additions and 3 deletions
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37
src/main/java/io/vertx/core/Future.java
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@@ -166,7 +166,31 @@ public interface Future<T> extends AsyncResult<T> {
* @return the composed future
*/
default <U> Future<U> compose(Function<T, Future<U>> mapper) {
if (mapper == null) {
return compose(mapper, Future::failedFuture);
}
/**
* Compose this future with a {@code successMapper} and {@code failureMapper} functions.<p>
*
* When this future (the one on which {@code compose} is called) succeeds, the {@code successMapper} will be called with
* the completed value and this mapper returns another future object. This returned future completion will complete
* the future returned by this method call.<p>
*
* When this future (the one on which {@code compose} is called) fails, the {@code failureMapper} will be called with
* the failure and this mapper returns another future object. This returned future completion will complete
* the future returned by this method call.<p>
*
* If any mapper function throws an exception, the returned future will be failed with this exception.<p>
*
* @param successMapper the function mapping the success
* @param failureMapper the function mapping the failure
* @return the composed future
*/
default <U> Future<U> compose(Function<T, Future<U>> successMapper, Function<Throwable, Future<U>> failureMapper) {
if (successMapper == null) {
throw new NullPointerException();
}
if (failureMapper == null) {
throw new NullPointerException();
}
Promise<U> ret = Promise.promise();
@@ -174,14 +198,21 @@ public interface Future<T> extends AsyncResult<T> {
if (ar.succeeded()) {
Future<U> apply;
try {
apply = mapper.apply(ar.result());
apply = successMapper.apply(ar.result());
} catch (Throwable e) {
ret.fail(e);
return;
}
apply.setHandler(ret);
} else {
ret.fail(ar.cause());
Future<U> apply;
try {
apply = failureMapper.apply(ar.cause());
} catch (Throwable e) {
ret.fail(e);
return;
}
apply.setHandler(ret);
}
});
return ret.future();