package com.example.google.guava.demo.collection;

import com.google.common.collect.BiMap;

import com.google.common.collect.HashBiMap;

import java.util.HashMap;

import java.util.Map;

import java.util.Set;

/**

 * <p>

 * <code>BimapTest</code>

 * </p>

 * Description:

 * 1.Bimap 的值唯一；

 *

 * @author Mcchu

 * @date 2017/10/19 16:45

 */

public class BimapTest {

    public static void main(String[] args) {

        BiMap<Integer, String> idMap = HashBiMap.create();

        idMap.put(101, "Mahesh");

        idMap.put(102, "Sohan");

        idMap.put(103, "Ramesh");

        // 1. 关联键的值

        Integer maheshId = idMap.inverse().get("Mahesh");

        System.out.println("1.名字为Mehesh的id："+maheshId);

        // 2. 空值

        idMap.put(null,"Jack");

        idMap.put(null,"Kite"); //BiMap 继承 Map，固键唯一，值覆盖

        idMap.put(104,null);

        //idMap.put (105,null);  // 抛 java.lang.IllegalArgumentException: value already present: null

        Set<String> values = idMap.values();

        System.out.print("2.输出所有值：");

        for ( String value:values ){

            System.out.print(value);

            System.out.print(",");

        }

        System.out.println();

        // 3. 包容另一个 map

        Map<Integer,String> anotherIdMap = new HashMap<>();

        anotherIdMap.put(105,"Jermy");

        anotherIdMap.put(106,"Mercy");

        anotherIdMap.put(107,"Abely");

        anotherIdMap.put(108,"Jalen");

        idMap.putAll(anotherIdMap);

        System.out.println("3.输出添加新Map过后的所有值：");

        for ( Integer id:idMap.keySet() ){

            System.out.println( "  key："+ id + ", value：" + idMap.get(id) );

        }

        System.out.println();

        // 4. 强制添加元素

        idMap.forcePut(109,null); // 强制添加 null，不会因已存在 null 而抛异常，但会覆盖，Bimap 始终允许一个值为 null

        Set<String> values1 = idMap.values();

        System.out.print("4.输出所有值：");

        for ( String value:values1 ){

            System.out.print(value);

            System.out.print(",");

        }

        System.out.println();

    }

}

package com.google.common.collect;

import com.google.common.annotations.GwtCompatible;

import com.google.errorprone.annotations.CanIgnoreReturnValue;

import java.util.Map;

import java.util.Set;

import javax.annotation.Nullable;

/**

 * A bimap (or "bidirectional map") is a map that preserves the uniqueness of

 * its values as well as that of its keys. This constraint enables bimaps to

 * support an "inverse view", which is another bimap containing the same entries

 * as this bimap but with reversed keys and values.

 *

 * <p>See the Guava User Guide article on <a href=

 * "https://github.com/google/guava/wiki/NewCollectionTypesExplained#bimap">

 * {@code BiMap}</a>.

 *

 * @author Kevin Bourrillion

 * @since 2.0

 */

@GwtCompatible

public interface BiMap<K, V> extends Map<K, V> {

  // Modification Operations

  /**

   * {@inheritDoc}

   *

   * @throws IllegalArgumentException if the given value is already bound to a

   *     different key in this bimap. The bimap will remain unmodified in this

   *     event. To avoid this exception, call {@link #forcePut} instead.

   */

  @CanIgnoreReturnValue

  @Override

  @Nullable

  V put(@Nullable K key, @Nullable V value);

  /**

   * An alternate form of {@code put} that silently removes any existing entry

   * with the value {@code value} before proceeding with the {@link #put}

   * operation. If the bimap previously contained the provided key-value

   * mapping, this method has no effect.

   *

   * <p>Note that a successful call to this method could cause the size of the

   * bimap to increase by one, stay the same, or even decrease by one.

   *

   * <p><b>Warning:</b> If an existing entry with this value is removed, the key

   * for that entry is discarded and not returned.

   *

   * @param key the key with which the specified value is to be associated

   * @param value the value to be associated with the specified key

   * @return the value which was previously associated with the key, which may

   *     be {@code null}, or {@code null} if there was no previous entry

   */

  @CanIgnoreReturnValue

  @Nullable

  V forcePut(@Nullable K key, @Nullable V value);

  // Bulk Operations

  /**

   * {@inheritDoc}

   *

   * <p><b>Warning:</b> the results of calling this method may vary depending on

   * the iteration order of {@code map}.

   *

   * @throws IllegalArgumentException if an attempt to {@code put} any

   *     entry fails. Note that some map entries may have been added to the

   *     bimap before the exception was thrown.

   */

  @Override

  void putAll(Map<? extends K, ? extends V> map);

  // Views

  /**

   * {@inheritDoc}

   *

   * <p>Because a bimap has unique values, this method returns a {@link Set},

   * instead of the {@link java.util.Collection} specified in the {@link Map}

   * interface.

   */

  @Override

  Set<V> values();

  /**

   * Returns the inverse view of this bimap, which maps each of this bimap's

   * values to its associated key. The two bimaps are backed by the same data;

   * any changes to one will appear in the other.

   *

   * <p><b>Note:</b>There is no guaranteed correspondence between the iteration

   * order of a bimap and that of its inverse.

   *

   * @return the inverse view of this bimap

   */

  BiMap<V, K> inverse();

}