Present.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;
import androidx.annotation.NonNull;
import androidx.annotation.Nullable;
import androidx.annotation.RequiresApi;
import androidx.core.util.Preconditions;
import androidx.core.util.Supplier;
/**
* Implementation of an {@link Optional} containing a reference.
*
* <p>Copied and adapted from Guava.
*/
@RequiresApi(21) // TODO(b/200306659): Remove and replace with annotation on package-info.java
final class Present<T> extends Optional<T> {
private final T mReference;
Present(T reference) {
mReference = reference;
}
@Override
public boolean isPresent() {
return true;
}
@NonNull
@Override
public T get() {
return mReference;
}
@NonNull
@Override
public T or(@NonNull T defaultValue) {
Preconditions.checkNotNull(defaultValue,
"use Optional.orNull() instead of Optional.or(null)");
return mReference;
}
@Override
public @NonNull Optional<T> or(@NonNull Optional<? extends T> secondChoice) {
Preconditions.checkNotNull(secondChoice);
return this;
}
@NonNull
@Override
public T or(@NonNull Supplier<? extends T> supplier) {
Preconditions.checkNotNull(supplier);
return mReference;
}
@Override
public T orNull() {
return mReference;
}
@Override
public boolean equals(@Nullable Object object) {
if (object instanceof Present) {
Present<?> other = (Present<?>) object;
return mReference.equals(other.mReference);
}
return false;
}
@Override
public int hashCode() {
return 0x598df91c + mReference.hashCode();
}
@NonNull
@Override
public String toString() {
return "Optional.of(" + mReference + ")";
}
private static final long serialVersionUID = 0;
}