97 lines
3.5 KiB
Java
97 lines
3.5 KiB
Java
/*
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* Copyright 2021 The Netty Project
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*
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* The Netty Project licenses this file to you under the Apache License,
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* version 2.0 (the "License"); you may not use this file except in compliance
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* with the License. You may obtain a copy of the License at:
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*
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* https://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
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* WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
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* License for the specific language governing permissions and limitations
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* under the License.
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*/
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package io.netty.util.concurrent;
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import java.util.concurrent.CancellationException;
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/**
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* A result of an asynchronous operation.
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* <p>
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* This interface is used as the super-interface of {@link Promise} and {@link Future}, and these should generally be
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* used instead.
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*/
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interface AsynchronousResult<V> {
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/**
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* Cancel this asynchronous operation, unless it has already been completed.
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* <p>
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* A cancelled operation is considered to be {@linkplain #isFailed() failed}.
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* <p>
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* If the cancellation was successful, the result of this operation will be that it has failed with a
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* {@link CancellationException}.
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* <p>
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* Cancellation will not cause any threads working on the operation to be {@linkplain Thread#interrupt()
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* interrupted}.
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*
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* @return {@code true} if the operation was cancelled by this call, otherwise {@code false}.
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*/
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boolean cancel();
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/**
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* Returns {@code true} if and only if the operation was completed successfully.
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*/
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boolean isSuccess();
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/**
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* Returns {@code true} if and only if the operation was completed and failed.
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*/
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boolean isFailed();
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/**
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* Return {@code true} if this operation has been {@linkplain #cancel() cancelled}.
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*
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* @return {@code true} if this operation has been cancelled, otherwise {@code false}.
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*/
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boolean isCancelled();
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/**
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* Return {@code true} if this operation has been completed either {@linkplain Promise#setSuccess(Object)
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* successfully}, {@linkplain Promise#setFailure(Throwable) unsuccessfully}, or through
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* {@linkplain #cancel() cancellation}.
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*
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* @return {@code true} if this operation has completed, otherwise {@code false}.
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*/
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boolean isDone();
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/**
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* returns {@code true} if and only if the operation can be cancelled via {@link #cancel()}.
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*/
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boolean isCancellable();
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/**
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* Return the successful result of this asynchronous operation, if any.
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* If the operation has not yet been completed, then this will throw {@link IllegalStateException}.
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* If the operation has been cancelled or failed with an exception, then this returns {@code null}.
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* Note that asynchronous operations can also be completed successfully with a {@code null} result.
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*
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* @return the result of this operation, if completed successfully.
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* @throws IllegalStateException if this {@code Future} or {@link Promise} has not completed yet.
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*/
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V getNow();
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/**
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* Returns the cause of the failed operation if the operation has failed.
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*
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* @return The cause of the failure, if any. Otherwise {@code null} if succeeded.
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* @throws IllegalStateException if this {@code Promise} has not completed yet.
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*/
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Throwable cause();
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/**
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* Returns the {@link EventExecutor} that is tied to this {@link Promise} or {@link Future}.
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*/
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EventExecutor executor();
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}
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