eaglercraft-1.8/sources/main/java/com/google/common/collect/SingletonImmutableBiMap.java

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2022-12-25 01:12:28 -08:00
/*
* Copyright (C) 2008 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.collect;
import static com.google.common.collect.CollectPreconditions.checkEntryNotNull;
import javax.annotation.Nullable;
import com.google.common.annotations.GwtCompatible;
/**
* Implementation of {@link ImmutableMap} with exactly one entry.
*
* @author Jesse Wilson
* @author Kevin Bourrillion
*/
@GwtCompatible(serializable = true, emulated = true)
@SuppressWarnings("serial") // uses writeReplace(), not default serialization
final class SingletonImmutableBiMap<K, V> extends ImmutableBiMap<K, V> {
final transient K singleKey;
final transient V singleValue;
SingletonImmutableBiMap(K singleKey, V singleValue) {
checkEntryNotNull(singleKey, singleValue);
this.singleKey = singleKey;
this.singleValue = singleValue;
}
private SingletonImmutableBiMap(K singleKey, V singleValue, ImmutableBiMap<V, K> inverse) {
this.singleKey = singleKey;
this.singleValue = singleValue;
this.inverse = inverse;
}
SingletonImmutableBiMap(Entry<? extends K, ? extends V> entry) {
this(entry.getKey(), entry.getValue());
}
@Override
public V get(@Nullable Object key) {
return singleKey.equals(key) ? singleValue : null;
}
@Override
public int size() {
return 1;
}
@Override
public boolean containsKey(@Nullable Object key) {
return singleKey.equals(key);
}
@Override
public boolean containsValue(@Nullable Object value) {
return singleValue.equals(value);
}
@Override
boolean isPartialView() {
return false;
}
@Override
ImmutableSet<Entry<K, V>> createEntrySet() {
return ImmutableSet.of(Maps.immutableEntry(singleKey, singleValue));
}
@Override
ImmutableSet<K> createKeySet() {
return ImmutableSet.of(singleKey);
}
transient ImmutableBiMap<V, K> inverse;
@Override
public ImmutableBiMap<V, K> inverse() {
// racy single-check idiom
ImmutableBiMap<V, K> result = inverse;
if (result == null) {
return inverse = new SingletonImmutableBiMap<V, K>(singleValue, singleKey, this);
} else {
return result;
}
}
}