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Guava is a suite of core and expanded libraries that include
utility classes, Google's collections, I/O classes, and
much more.
This project includes GWT-friendly sources.
/*
* 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 com.google.common.annotations.GwtCompatible;
import java.util.Collections;
import java.util.Set;
import javax.annotation.CheckForNull;
/** Implementation of an {@link Optional} containing a reference. */
@GwtCompatible
@ElementTypesAreNonnullByDefault
final class Present extends Optional {
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 or(Optional secondChoice) {
checkNotNull(secondChoice);
return this;
}
@Override
public T or(Supplier supplier) {
checkNotNull(supplier);
return reference;
}
@Override
public T orNull() {
return reference;
}
@Override
public Set asSet() {
return Collections.singleton(reference);
}
@Override
public Optional transform(Function function) {
return new Present(
checkNotNull(
function.apply(reference),
"the Function passed to Optional.transform() must not return null."));
}
@Override
public boolean equals(@CheckForNull 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;
}