com.google.common.collect.HashBiMap Maven / Gradle / Ivy
/*
* Copyright (C) 2007 Google Inc.
*
* 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 com.google.common.annotations.GwtCompatible;
import java.io.IOException;
import java.io.ObjectInputStream;
import java.io.ObjectOutputStream;
import java.util.HashMap;
import java.util.Map;
import javax.annotation.Nullable;
/**
* A {@link BiMap} backed by two {@link HashMap} instances. This implementation
* allows null keys and values. A {@code HashBiMap} and its inverse are both
* serializable.
*
* @author Mike Bostock
* @since 2 (imported from Google Collections Library)
*/
@GwtCompatible
public final class HashBiMap extends AbstractBiMap {
/**
* Returns a new, empty {@code HashBiMap} with the default initial capacity
* (16).
*/
public static HashBiMap create() {
return new HashBiMap();
}
/**
* 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 HashBiMap create(int expectedSize) {
return new HashBiMap(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 HashBiMap create(
Map map) {
HashBiMap bimap = create(map.size());
bimap.putAll(map);
return bimap;
}
private HashBiMap() {
super(new HashMap(), new HashMap());
}
private HashBiMap(int expectedSize) {
super(new HashMap(Maps.capacity(expectedSize)),
new HashMap(Maps.capacity(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);
}
/**
* @serialData the number of entries, first key, first value, second key,
* second value, and so on.
*/
private void writeObject(ObjectOutputStream stream) throws IOException {
stream.defaultWriteObject();
Serialization.writeMap(this, stream);
}
private void readObject(ObjectInputStream stream)
throws IOException, ClassNotFoundException {
stream.defaultReadObject();
int size = Serialization.readCount(stream);
setDelegates(Maps.newHashMapWithExpectedSize(size),
Maps.newHashMapWithExpectedSize(size));
Serialization.populateMap(this, stream, size);
}
private static final long serialVersionUID = 0;
}