InternalFutures.java
/*
* Copyright 2019 The Android Open Source Project
*
* 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 androidx.camera.core.impl.utils.futures.internal;
import androidx.annotation.RestrictTo;
/**
* Cloned from concurrent-futures package in Guava to AndroidX namespace since we would need
* ListenableFuture related implementation but not want to include whole Guava library.
*
* Static utilities for {@link InternalFutureFailureAccess}. Most users will never need to use this
* class.
*
* <p>This class is GWT-compatible.
*
* @since {@code com.google.guava:failureaccess:1.0}, which was added as a dependency of Guava in
* Guava 27.0
* @hide
*/
@RestrictTo(RestrictTo.Scope.LIBRARY_GROUP)
public final class InternalFutures {
/**
* Usually returns {@code null} but, if the given {@code Future} has failed, may
* <i>optionally</i> return the cause of the failure. "Failure" means specifically "completed
* with an exception"; it does not include "was cancelled." To be explicit: If this method
* returns a non-null value, then:
*
* <ul>
* <li>{@code isDone()} must return {@code true}
* <li>{@code isCancelled()} must return {@code false}
* <li>{@code get()} must not block, and it must throw an {@code ExecutionException} with the
* return value of this method as its cause
* </ul>
*/
public static Throwable tryInternalFastPathGetFailure(InternalFutureFailureAccess future) {
return future.tryInternalFastPathGetFailure();
}
private InternalFutures() {}
}