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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 net.dv8tion.jda.internal.utils.Checks;
import javax.annotation.Nonnull;
import java.time.Duration;
import java.util.concurrent.TimeUnit;
import java.util.function.Consumer;
/**
* Represents an asynchronous task.
*
Note: The underlying task may already be started.
*
* @param
* The result type
*/
public interface Task
{
/**
* Whether this task has started.
*
* @return True, if this task has already started.
*/
boolean isStarted();
/**
* Provide a callback for exception handling.
*
This is an asynchronous operation.
*
* The error will be logged regardless of your callback, this only exists to handle
* failures for other purposes.
*
* @param callback
* The error callback
*
* @throws IllegalArgumentException
* If null is provided
*
* @return The current Task instance for chaining
*/
@Nonnull
Task onError(@Nonnull Consumer callback);
/**
* Provide a callback for success handling.
*
This is an asynchronous operation.
*
* @param callback
* The success callback
*
* @throws IllegalArgumentException
* If null is provided
*
* @return The current Task instance for chaining
*/
@Nonnull
Task onSuccess(@Nonnull Consumer callback);
/**
* Change the timeout duration for this task.
*
This may be ignored for certain operations.
*
* The provided timeout is relative to the start time of the task.
* If the time has already passed, this will immediately cancel the task.
*
* @param timeout
* The new timeout duration
*
* @throws IllegalArgumentException
* If null is provided or the timeout is not positive
*
* @return The current Task instance for chaining
*/
@Nonnull
Task setTimeout(@Nonnull Duration timeout);
/**
* Change the timeout duration for this task.
*
This may be ignored for certain operations.
*
* The provided timeout is relative to the start time of the task.
* If the time has already passed, this will immediately cancel the task.
*
* @param timeout
* The new timeout duration
* @param unit
* The time unit of the timeout
*
* @throws IllegalArgumentException
* If null is provided or the timeout is not positive
*
* @return The current Task instance for chaining
*/
@Nonnull
default Task setTimeout(long timeout, TimeUnit unit)
{
Checks.notNull(unit, "TimeUnit");
return setTimeout(Duration.ofMillis(unit.toMillis(timeout)));
}
/**
* Blocks the current thread until the result is ready.
*
This will not work on the default JDA event thread because it might depend on other events to be processed,
* which could lead to a deadlock.
*
* @throws UnsupportedOperationException
* If this is called on the default JDA event thread
* @throws java.util.concurrent.CompletionException
* If some exception occurred (such as {@link java.util.concurrent.TimeoutException}).
* @throws java.util.concurrent.CancellationException
* If the request was cancelled
*
* @return The result value
*/
@Nonnull
T get();
/**
* Cancels the task and will emit a {@link java.util.concurrent.CancellationException CancellationException}.
*/
void cancel();
}