Java EnumMap get() Method

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Description

The Java EnumMap get(Object key) method returns the value to which the specified key is mapped, or null if this map contains no mapping for the key.

Declaration

Following is the declaration for java.util.EnumMap.get() method

public V get(Object key)

Parameters

key − the key whose associated value is to be returned

Return Value

This method returns the value to which the specified key is mapped, or null if this map contains no mapping for the key.

Exception

NA

Getting a Value based on Key From an EnumMap of Enum, Integer Pairs Example

The following example shows the usage of Java EnumMap get(Object) method to get a value from the EnumMap instance based on a key passed. We've created a enum Numbers. Then EnumMap is created of enum Numbers and Integer. Few entries are added and enumMap is printed. Using get() method, a value of enumMap is printed.

package com.tutorialspoint;

import java.util.EnumMap;

public class EnumMapDemo {
   
   // create an enum
   public enum Numbers{ONE, TWO, THREE, FOUR, FIVE}; 

   public static void main(String[] args) {
      
      EnumMap<Numbers,Integer> map = 
         new EnumMap<>(Numbers.class);

      // associate values in map
      map.put(Numbers.ONE, 1);
      map.put(Numbers.TWO, 2);
      map.put(Numbers.THREE,3);
      map.put(Numbers.FOUR, 4);

      // print the whole map
      System.out.println(map); 

      // get a value based on a key
      System.out.println(map.get(Numbers.TWO));
   }
}

Output

Let us compile and run the above program, this will produce the following result −

{ONE=1, TWO=2, THREE=3, FOUR=4}
2

Getting a Value based on Key From an EnumMap of Enum, String Pairs Example

The following example shows the usage of Java EnumMap get(Object) method to get a value from the EnumMap instance based on a key passed. We've created a enum Numbers. Then EnumMap is created of enum Numbers and String. Few entries are added and enumMap is printed. Using get() method, a value of enumMap is printed.

package com.tutorialspoint;

import java.util.EnumMap;

public class EnumMapDemo {
   
   // create an enum
   public enum Numbers{ONE, TWO, THREE, FOUR, FIVE}; 

   public static void main(String[] args) {
      
      EnumMap<Numbers,String> map = 
         new EnumMap<>(Numbers.class);

      // associate values in map
      map.put(Numbers.ONE, "1");
      map.put(Numbers.TWO, "2");
      map.put(Numbers.THREE,"3");
      map.put(Numbers.FOUR, "4");

      // print the whole map
      System.out.println(map); 

      // get a value based on a key
      System.out.println(map.get(Numbers.TWO));
   }
}

Output

Let us compile and run the above program, this will produce the following result −

{ONE=1, TWO=2, THREE=3, FOUR=4}
2

Getting a Value based on Key From an EnumMap of Enum, Object Pairs Example

The following example shows the usage of Java EnumMap get(Object) method to get a value from the EnumMap instance based on a key passed. We've created a enum Numbers. Then EnumMap is created of enum Numbers and Student objects. Few entries are added and enumMap is printed. Using get() method, a value of enumMap is printed.

package com.tutorialspoint;

import java.util.EnumMap;

public class EnumMapDemo {
   
   // create an enum
   public enum Numbers{ONE, TWO, THREE, FOUR, FIVE}; 

   public static void main(String[] args) {
      
      EnumMap<Numbers,Student> map = 
         new EnumMap<>(Numbers.class);

      // associate values in map
      map.put(Numbers.ONE, new Student(1, "Julie"));
      map.put(Numbers.TWO, new Student(2, "Robert"));
      map.put(Numbers.THREE,new Student(3, "Adam"));
      map.put(Numbers.FOUR, new Student(4, "Jene"));

      // print the whole map
      System.out.println(map); 

      // get a value based on a key
      System.out.println(map.get(Numbers.TWO)); 
   }
}
class Student {
   int rollNo;
   String name;

   Student(int rollNo, String name){
      this.rollNo = rollNo;
      this.name = name;
   }

   @Override
   public String toString() {
      return "[ " + this.rollNo + ", " + this.name + " ]";
   }
}

Output

Let us compile and run the above program, this will produce the following result −

{ONE=[ 1, Julie ], TWO=[ 2, Robert ], THREE=[ 3, Adam ], FOUR=[ 4, Jene ]}
[ 2, Robert ]