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/*
* Copyright 2015 Austin Keener, Michael Ritter, Florian Spieß, and the JDA contributors
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package net.dv8tion.jda.api.utils.concurrent;
import javax.annotation.Nonnull;
import java.util.concurrent.*;
import java.util.function.Function;
/**
* Specialized {@link CompletableFuture} used in combination with a scheduler.
*
* @param
* The result type
*
* @since 4.0.0
*
* @see CompletableFuture
* @see Delayed
*/
public class DelayedCompletableFuture extends CompletableFuture implements ScheduledFuture
{
private ScheduledFuture future;
private DelayedCompletableFuture() {}
/**
* Creates a new DelayedCompletableFuture scheduled on the supplied executor.
*
* @param executor
* The {@link ScheduledExecutorService} to use for scheduling
* @param delay
* The delay of the task
* @param unit
* Conversion {@link TimeUnit} for the delay
* @param mapping
* Conversion function which calls {@link #complete(Object)} of the future it receives
* @param
* The result type of the scheduled task
*
* @return DelayedCompletableFuture for the specified runnable
*/
@Nonnull
public static DelayedCompletableFuture make(@Nonnull ScheduledExecutorService executor, long delay, @Nonnull TimeUnit unit, @Nonnull Function, ? extends Runnable> mapping)
{
DelayedCompletableFuture handle = new DelayedCompletableFuture<>();
ScheduledFuture future = executor.schedule(mapping.apply(handle), delay, unit);
handle.initProxy(future);
return handle;
}
/**
* Initializes the backing scheduled task for this promise.
*
* The provided future will be cancelled when {@link #cancel(boolean)} is invoked
* and is used as provider for {@link #getDelay(TimeUnit)}.
*
* @param future
* The future that should be cancelled when this task is cancelled
*
* @throws IllegalStateException
* If this was already initialized
*/
private void initProxy(ScheduledFuture future)
{
if (this.future == null)
this.future = future;
else
throw new IllegalStateException("Cannot initialize twice");
}
@Override
public boolean cancel(boolean mayInterruptIfRunning)
{
if (future != null && !future.isDone())
future.cancel(mayInterruptIfRunning);
return super.cancel(mayInterruptIfRunning);
}
@Override
public long getDelay(@Nonnull TimeUnit unit)
{
return future.getDelay(unit);
}
@Override
public int compareTo(@Nonnull Delayed o)
{
return future.compareTo(o);
}
}