de.quantummaid.mapmaid.collections.BiMap Maven / Gradle / Ivy
/*
* Copyright (c) 2020 Richard Hauswald - https://quantummaid.de/.
*
* Licensed to the Apache Software Foundation (ASF) under one
* or more contributor license agreements. See the NOTICE file
* distributed with this work for additional information
* regarding copyright ownership. The ASF licenses this file
* to you 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 de.quantummaid.mapmaid.collections;
import lombok.AccessLevel;
import lombok.EqualsAndHashCode;
import lombok.RequiredArgsConstructor;
import lombok.ToString;
import java.util.ArrayList;
import java.util.List;
import java.util.Map;
import java.util.Map.Entry;
import java.util.Optional;
import java.util.function.BiConsumer;
import static java.util.stream.Collectors.toMap;
@ToString
@EqualsAndHashCode
@RequiredArgsConstructor(access = AccessLevel.PRIVATE)
public final class BiMap {
private final Map byA;
private final Map byB;
public static BiMap biMap(final Map map) {
final Map byB = map.entrySet()
.stream()
.collect(toMap(Entry::getValue, Entry::getKey));
return new BiMap<>(map, byB);
}
public Optional lookup(final A key) {
return Optional.ofNullable(byA.get(key));
}
public Optional reverseLookup(final B key) {
return Optional.ofNullable(byB.get(key));
}
public int size() {
return byA.size();
}
public void forEach(final BiConsumer super A, ? super B> action) {
byA.forEach(action);
}
public List values() {
return new ArrayList<>(byA.values());
}
public List keys() {
return new ArrayList<>(byA.keySet());
}
}
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