com.google.common.collect.HashBiMap.java Source code

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Here is the source code for com.google.common.collect.HashBiMap.java

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/*
 * Copyright (C) 2007 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 java.util.HashMap;
import java.util.Map;

import javax.annotation.Nullable;

/**
 * GWT emulation of {@code HashBiMap} that just delegates to two HashMaps.
 *
 * @author Mike Bostock
 */
public final class HashBiMap<K, V> extends AbstractBiMap<K, V> {

    /**
     * Returns a new, empty {@code HashBiMap} with the default initial capacity
     * (16).
     */
    public static <K, V> HashBiMap<K, V> create() {
        return new HashBiMap<K, V>();
    }

    /**
     * Constructs a new, empty bimap with the specified expected size.
     *
     * @param expectedSize the expected number of entries
     * @throws IllegalArgumentException if the specified expected size is
     *     negative
     */
    public static <K, V> HashBiMap<K, V> create(int expectedSize) {
        return new HashBiMap<K, V>(expectedSize);
    }

    /**
     * Constructs a new bimap containing initial values from {@code map}. The
     * bimap is created with an initial capacity sufficient to hold the mappings
     * in the specified map.
     */
    public static <K, V> HashBiMap<K, V> create(Map<? extends K, ? extends V> map) {
        HashBiMap<K, V> bimap = create(map.size());
        bimap.putAll(map);
        return bimap;
    }

    private HashBiMap() {
        super(new HashMap<K, V>(), new HashMap<V, K>());
    }

    private HashBiMap(int expectedSize) {
        super(Maps.<K, V>newHashMapWithExpectedSize(expectedSize),
                Maps.<V, K>newHashMapWithExpectedSize(expectedSize));
    }

    // Override these two methods to show that keys and values may be null

    @Override
    public V put(@Nullable K key, @Nullable V value) {
        return super.put(key, value);
    }

    @Override
    public V forcePut(@Nullable K key, @Nullable V value) {
        return super.forcePut(key, value);
    }
}