104 lines
2.3 KiB
Java
104 lines
2.3 KiB
Java
/*
|
|
* Copyright (C) 2011 The Guava Authors
|
|
*
|
|
* 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 com.google.common.base;
|
|
|
|
import static com.google.common.base.Preconditions.checkNotNull;
|
|
|
|
import java.util.Collections;
|
|
import java.util.Set;
|
|
|
|
import javax.annotation.Nullable;
|
|
|
|
import com.google.common.annotations.GwtCompatible;
|
|
|
|
/**
|
|
* Implementation of an {@link Optional} containing a reference.
|
|
*/
|
|
@GwtCompatible
|
|
final class Present<T> extends Optional<T> {
|
|
private final T reference;
|
|
|
|
Present(T reference) {
|
|
this.reference = reference;
|
|
}
|
|
|
|
@Override
|
|
public boolean isPresent() {
|
|
return true;
|
|
}
|
|
|
|
@Override
|
|
public T get() {
|
|
return reference;
|
|
}
|
|
|
|
@Override
|
|
public T or(T defaultValue) {
|
|
checkNotNull(defaultValue, "use Optional.orNull() instead of Optional.or(null)");
|
|
return reference;
|
|
}
|
|
|
|
@Override
|
|
public Optional<T> or(Optional<? extends T> secondChoice) {
|
|
checkNotNull(secondChoice);
|
|
return this;
|
|
}
|
|
|
|
@Override
|
|
public T or(Supplier<? extends T> supplier) {
|
|
checkNotNull(supplier);
|
|
return reference;
|
|
}
|
|
|
|
@Override
|
|
public T orNull() {
|
|
return reference;
|
|
}
|
|
|
|
@Override
|
|
public Set<T> asSet() {
|
|
return Collections.singleton(reference);
|
|
}
|
|
|
|
@Override
|
|
public <V> Optional<V> transform(Function<? super T, V> function) {
|
|
return new Present<V>(checkNotNull(function.apply(reference),
|
|
"the Function passed to Optional.transform() must not return null."));
|
|
}
|
|
|
|
@Override
|
|
public boolean equals(@Nullable Object object) {
|
|
if (object instanceof Present) {
|
|
Present<?> other = (Present<?>) object;
|
|
return reference.equals(other.reference);
|
|
}
|
|
return false;
|
|
}
|
|
|
|
@Override
|
|
public int hashCode() {
|
|
return 0x598df91c + reference.hashCode();
|
|
}
|
|
|
|
@Override
|
|
public String toString() {
|
|
return "Optional.of(" + reference + ")";
|
|
}
|
|
|
|
private static final long serialVersionUID = 0;
|
|
}
|