WeakHashMap containsValue() Method in Java
Last Updated :
19 Jul, 2018
The java.util.WeakHashMap.containsValue() method is used to check whether a particular value is being mapped by a single or more than one key in the WeakHashMap. It takes the Value as a parameter and returns True if that value is mapped by any of the key in the map.
Syntax:
Weak_Hash_Map.containsValue(Object Value)
Parameters: The method takes just one parameter Value of Object type and refers to the value whose mapping is supposed to be checked by any key inside the map.
Return Value: The method returns boolean true if the mapping of the value is detected else false.
Below programs illustrate the java.util.WeakHashMap.containsValue() Method:
Program 1: Mapping String Values to Integer Keys.
import java.util.*;
public class Weak_Hash_Map_Demo {
public static void main(String[] args)
{
Map<Integer, String> weak_hash = new WeakHashMap<Integer, String>();
weak_hash.put( 10 , "Geeks" );
weak_hash.put( 15 , "4" );
weak_hash.put( 20 , "Geeks" );
weak_hash.put( 25 , "Welcomes" );
weak_hash.put( 30 , "You" );
System.out.println( "Initial Mappings are: " + weak_hash);
System.out.println( "Is the value 'Geeks' present? " +
weak_hash.containsValue( "Geeks" ));
System.out.println( "Is the value 'World' present? " +
weak_hash.containsValue( "World" ));
}
}
|
Output:
Initial Mappings are: {30=You, 15=4, 10=Geeks, 25=Welcomes, 20=Geeks}
Is the value 'Geeks' present? true
Is the value 'World' present? false
Program 2: Mapping Integer Values to String Keys.
import java.util.*;
public class Weak_Hash_Map_Demo {
public static void main(String[] args)
{
Map<String, Integer> weak_hash = new WeakHashMap<String, Integer>();
weak_hash.put( "Geeks" , 10 );
weak_hash.put( "4" , 15 );
weak_hash.put( "Geeks" , 20 );
weak_hash.put( "Welcomes" , 25 );
weak_hash.put( "You" , 30 );
System.out.println( "Initial Mappings are: " + weak_hash);
System.out.println( "Is the value '10' present? " +
weak_hash.containsValue( 10 ));
System.out.println( "Is the value '30' present? " +
weak_hash.containsValue( 30 ));
System.out.println( "Is the value '40' present? " +
weak_hash.containsValue( 40 ));
}
}
|
Output:
Initial Mappings are: {Welcomes=25, 4=15, You=30, Geeks=20}
Is the value '10' present? false
Is the value '30' present? true
Is the value '40' present? false
Note: The same operation can be performed with any type of Mappings with variation and combination of different data types.
Like Article
Suggest improvement
Share your thoughts in the comments
Please Login to comment...