Pair
Function
JavaFX 2.2 has the javafx.util.Pair class which can be used to store a pair.
<Key, Value> simply refers to a pair of values that are stored together.
Pairs provide a convenient way of handling simple key to value association and are particularly useful when we want to return two values from a method.
NOTE!- You need to have Java 8 installed on your machine in order to run the below program.
Syntax
//This returns an object of Pair class with key of Type T1 and Value of Type T2
Pair <T1, T2> p = new Pair <> (val1, val2);
Parameters
val1 : Key of type T1
val2 : Value for key val1, of type T2
Methods of Pair Class
Method | Description |
---|---|
Pair (K key, V value) | Creates a new pair |
boolean equals() | It is used to compare two pair objects. It compares on the basic of the values (<Key, Value>) which are stored in the pair objects. |
String toString() | It returns the String representation of the Pair. |
K getKey() | It returns key for the pair. |
V getValue() | It returns value for the pair. |
int hashCode() | Generates a hash code for the Pair. |
Example
import javafx.util.Pair;
public class Main
{
public static void main(String args[])
{
Pair <String, Integer> p1 =new Pair<>("Mumbai",6);
Pair <String, Integer> p2 =new Pair<>("Chennai",7);
Pair <String, Integer> p3 =new Pair<>("Bombay",6);
Pair <String, Integer> p4 =new Pair<>("Mumbai",6);
//equals method example
System.out.println(p1.equals(p2));
System.out.println(p1.equals(p3));
System.out.println(p1.equals(p4));
//toString example
System.out.println(p1.toString());
//getKey and getValue example
System.out.println("Number of alphabets in "+p1.getKey()+" is "+p1.getValue());
}
}
Output
false
false
true
Mumbai=6
Number of alphabets in Mumbai is 6