Guava - BiMap Interface

A BiMap is a special kind of map which maintains an inverse view of the map while ensuring that no duplicate values are present in the map and a value can be used safely to get the key back.

Interface Declaration

Following is the declaration for com.google.common.collect.Bimap<K,V> interface −

@GwtCompatible
public interface BiMap<K,V>
   extends Map<K,V>

Interface Methods

Sr.No	Method & Description
1	V forcePut(K key, V value) An alternate form of 'put' that silently removes any existing entry with the value before proceeding with the put(K, V) operation.
2	BiMap<V,K> inverse() Returns the inverse view of this bimap, which maps each of this bimap's values to its associated key.
3	V put(K key, V value) Associates the specified value with the specified key in this map (optional operation).
4	void putAll(Map<? extends K,? extends V> map) Copies all of the mappings from the specified map to this map (optional operation).
5	Set<V> values() Returns a Collection view of the values contained in this map.

Methods Inherited

This class inherits methods from the following interface −

• java.util.Map

Example - Adding values to a BiMap

GuavaTester.java

package com.tutorialspoint;

import com.google.common.collect.BiMap;
import com.google.common.collect.HashBiMap;

public class GuavaTester {

   public static void main(String args[]) {
      BiMap<Integer, String> empIDNameMap = HashBiMap.create();

      empIDNameMap.put(Integer.valueOf(101), "Mahesh");
      empIDNameMap.put(Integer.valueOf(102), "Sohan");
      empIDNameMap.put(Integer.valueOf(103), "Ramesh");

      // Get Name of Employee with Emp Id 101
      System.out.println(empIDNameMap.get(Integer.valueOf(101)));
   }	
}

Output

Run the GuavaTester and verify the output −

Mahesh

Example - Getting Key based on Value from a BiMap

GuavaTester.java

package com.tutorialspoint;

import com.google.common.collect.BiMap;
import com.google.common.collect.HashBiMap;

public class GuavaTester {

   public static void main(String args[]) {
      BiMap<Integer, String> empIDNameMap = HashBiMap.create();

      empIDNameMap.put(Integer.valueOf(101), "Mahesh");
      empIDNameMap.put(Integer.valueOf(102), "Sohan");
      empIDNameMap.put(Integer.valueOf(103), "Ramesh");
      
      //Emp Id of Employee "Mahesh"
      System.out.println(empIDNameMap.inverse().get("Mahesh"));
   }	
}

Output

Run the GuavaTester and verify the output −

101

Example - Getting values of a BiMap

GuavaTester.java

package com.tutorialspoint;

import java.util.Collection;

import com.google.common.collect.BiMap;
import com.google.common.collect.HashBiMap;

public class GuavaTester {

   public static void main(String args[]) {
      BiMap<Integer, String> empIDNameMap = HashBiMap.create();

      empIDNameMap.put(Integer.valueOf(101), "Mahesh");
      empIDNameMap.put(Integer.valueOf(102), "Sohan");
      empIDNameMap.put(Integer.valueOf(103), "Ramesh");
      
      System.out.println("Values of Bimap");
      Collection<String> values = empIDNameMap.values();
      System.out.println(values);
   }	
}

Output

Run the GuavaTester and verify the output −

Values of Bimap
[Mahesh, Sohan, Ramesh]