org.jgroups.util.CompletableFutures Maven / Gradle / Ivy
package org.jgroups.util;
import java.util.concurrent.CompletableFuture;
import java.util.concurrent.CompletionException;
import java.util.concurrent.CompletionStage;
import java.util.function.Consumer;
import java.util.function.Function;
/**
* Utility class with {@link CompletableFuture} and {@link CompletionStage} useful methods.
*
* @author Pedro Ruivo
* @since 5.2
*/
public enum CompletableFutures {
INSTANCE;
private static final CompletableFuture NULL = CompletableFuture.completedFuture(null);
private static final CompletableFuture TRUE_CF = CompletableFuture.completedFuture(Boolean.TRUE);
private static final CompletableFuture FALSE_CF = CompletableFuture.completedFuture(Boolean.FALSE);
private static final Consumer VOID_CONSUMER = o -> {
};
private static final Function NULL_FUNCTION = o -> null;
/**
* Same as {@link #join(CompletableFuture)} but it receives a {@link CompletionStage} as parameter.
*
* @see #join(CompletableFuture)
*/
public static T join(CompletionStage cs) {
return join(cs.toCompletableFuture());
}
/**
* Waits for the {@link CompletableFuture} to complete.
*
* Any non {@link RuntimeException} thrown is converted to a {@link RuntimeException}.
*
* @param cf The {@link CompletableFuture}
* @param The value type.
* @return The value of the completed {@link CompletableFuture}.
*/
public static T join(CompletableFuture cf) {
try {
return cf.join();
} catch (CompletionException e) {
if (e.getCause() instanceof RuntimeException) {
throw (RuntimeException) e.getCause();
}
throw new RuntimeException(e.getCause());
}
}
/**
* A {@code null} completed {@link CompletableFuture}.
*
* @param The value type.
* @return The {@link CompletableFuture}.
*/
public static CompletableFuture completedNull() {
//noinspection unchecked
return (CompletableFuture) NULL;
}
/**
* Consumes any value and return a {@link Void}.
*
* @param The value type.
* @return The {@link Consumer}.
*/
public static Consumer voidConsumer() {
//noinspection unchecked
return (Consumer) VOID_CONSUMER;
}
/**
* Wraps the {@code throwable} into {@link CompletionException}.
*
* @param throwable The {@link Throwable} to wrap.
* @return The {@link CompletionException} with {@code throwable}.
*/
public static CompletionException wrapAsCompletionException(Throwable throwable) {
return throwable instanceof CompletionException ?
(CompletionException) throwable :
new CompletionException(throwable);
}
/**
* @param The value's type.
* @return A {@link Function} that converts any value to {@link Void}.
*/
public static Function toVoidFunction() {
//noinspection unchecked
return (Function) NULL_FUNCTION;
}
/**
* @return A {@link CompletableFuture} completed with value {@link Boolean#TRUE}
*/
public static CompletableFuture completedTrue() {
return TRUE_CF;
}
/**
* @return A {@link CompletableFuture} completed with value {@link Boolean#FALSE}
*/
public static CompletableFuture completedFalse() {
return FALSE_CF;
}
}