/
Task.java
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/
Task.java
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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.function.Consumer;
/**
* Represents an asynchronous task.
* <br>Note: The underlying task may already be started.
*
* @param <T>
* The result type
*/
public interface Task<T>
{
/**
* Whether this task has started.
*
* @return True, if this task has already started.
*/
boolean isStarted();
/**
* Provide a callback for exception handling.
* <br>This is an asynchronous operation.
*
* <p>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<T> onError(@Nonnull Consumer<? super Throwable> callback);
/**
* Provide a callback for success handling.
* <br>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<T> onSuccess(@Nonnull Consumer<? super T> callback);
/**
* Blocks the current thread until the result is ready.
* <br>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();
}