HashMap forEach(BiConsumer) method in Java with Examples
The forEach(BiConsumer) method of HashMap class perform the BiConsumer operation on each entry of hashmap until all entries have been processed or the action throws an exception. The BiConsumer operation is a function operation of the key-value pair of hashtable performed in the order of iteration. Method traverses each element of Hashtable until all elements have been processed by the method or an exception occurs. Exceptions thrown by the Operation are passed to the caller.
Syntax:
public void forEach(BiConsumer action)
Parameters: This method accepts a parameter action of BiConsumer type that represents what action are to be performed on the HashMap elements.
Returns: This method do not return anything.
Exceptions: This method throws NullPointerException if the action is null.
Below programs illustrate the forEach(BiConsumer) method:
Program 1: to traverse a hashmap using action
import java.util.HashMap;
import java.util.Map;
import java.util.function.BiConsumer;
public class GFG {
public static void main(String[] args)
{
Map<String, Integer> map
= new HashMap<>();
map.put( "geeks" , 55 );
map.put( "for" , 13 );
map.put( "geeks" , 22 );
map.put( "is" , 11 );
map.put( "heaven" , 90 );
map.put( "for" , 100 );
map.put( "geekies like us" , 96 );
BiConsumer<String, Integer> action
= new MyBiConsumer();
map.forEach(action);
}
}
class MyBiConsumer implements BiConsumer<String, Integer> {
public void accept(String k, Integer v)
{
System.out.print( "Key = " + k);
System.out.print( "\t Value = " + v);
System.out.println();
}
}
|
Output:
Key = geeks Value = 22
Key = for Value = 100
Key = is Value = 11
Key = heaven Value = 90
Key = geekies like us Value = 96
Program 2:
import java.util.HashMap;
import java.util.Map;
import java.util.function.BiConsumer;
public class GFG {
public static void main(String[] args)
{
Map<String, Integer> map
= new HashMap<>();
map.put( "geeks" , 55 );
map.put( "for" , 13 );
map.put( "geeks" , 22 );
map.put( "is" , 11 );
map.put( "heaven" , 90 );
map.put( "for" , 100 );
map.put( "geekies like us" , 96 );
BiConsumer<String, Integer> action
= new MyBiConsumer();
map.forEach(action);
}
}
class MyBiConsumer implements BiConsumer<String, Integer> {
public void accept(String k, Integer v)
{
System.out.println( "Key: " + k
+ "\tValue: " + v);
if ( "for" .equals(k)) {
System.out.println( "Its the "
+ "highest value\n" );
}
}
}
|
Output:
Key: geeks Value: 22
Key: for Value: 100
Its the highest value
Key: is Value: 11
Key: heaven Value: 90
Key: geekies like us Value: 96
Reference: https://docs.oracle.com/javase/8/docs/api/java/util/HashMap.html#forEach-java.util.function.BiConsumer-
Last Updated :
11 Oct, 2019
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