Table of Contents

JavaTuples – Pair Class

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Introduction

The org.javatuples.Pair class represents a Tuple with two elements.

Class Declaration

Following is the declaration for org.javatuples.Pair class −

public final class Pair<A,B>
   extends Tuple
      implements IValue0<A>, IValue1<B>

Class Constructor

Sr.No.	Constructor & Description
1	Pair(A value0, B value1) This creates a Pair Tuple.

Class Methods

Similarly setAt1() set the value at index 1.

Sr.No.	Method & Description
1	Triplet add(Unit tuple) This method returns a Triplet tuple. Similarly other methods to add tuples are available e.g. add(Pair tuple) returns Quartet and upto add(Octet tuple) returns Decade tuple.
2	Triplet add(X0 value) This method add a value to the tuple and returns a Triplet tuple. Similarly other methods to add values are available e.g. add(X0 value0, X1 value1) returns Quartet and so on upto add() with eight parameters.
3	Triplet addAt0(Unit value) This method add a Unit tuple at index 0 and returns a Triplet tuple. Similarly other methods to add tuples are available e.g. addAt0(Pair value) returns Quartet and so on upto addAt0(Octet). Other similar method are addAt1(Unit value) which add a unit at index0 and have similar methods upto addAt2(Octet).
4	Triplet addAt0(X0 value) This method add a value at index 0 and returns a Triplet tuple. Similarly other methods to add values are available e.g. addAt0(X0 value0, X1 value1) returns Quartet and so on upto addAt0() with eight parameters. Other similar method are addAt1(X0 value) which add a value at index0 and have similar methods upto addAt2() with eight parameters.
5	static <X> Pair<X,X> fromArray(X[] array) Create tuple from array.
6	static <X> Pair<X,X> fromCollection(Collection<X> collection) Create tuple from collection.
7	static <X> Pair<X,X> fromIterable(Iterable<X> iterable) Create tuple from iterable.
8	static <X> Pair<X,X> fromIterable(Iterable<X> iterable, int index) Create tuple from iterable, starting from the specified index.
9	int getSize() Return the size of the tuple.
10	A getValue0() Returns the value of the tuple at index 0. Similarly getValue1() returns the value at index 1.
11	Unit<B> removeFrom0() Return the tuple after removing value of the tuple at index 0. Similarly removeFrom1() returns the tuple after removing value of the tuple at index 1.
12	<X> Pair<X,B> setAt0(X value) Set the value of the tuple at index 0.
13	static <A,B> Pair<A,B> with(A value0, B value1) Create the tuple using given value.

Methods inherite

This class inherits methods from the following classes −

org.javatuples.Tuple
Object

Example

Let”s see Pair Class in action. Here we”ll see how to use various methods.

Create a java class file named TupleTester in C:>JavaTuples.

File: TupleTester.java

package com.tutorialspoint;
import java.util.ArrayList;
import java.util.List;
import org.javatuples.Pair;
import org.javatuples.Triplet;
import org.javatuples.Unit;

public class TupleTester {
   public static void main(String args[]){
      Pair<Integer, Integer> pair = Pair.with(5,6);
      System.out.println(pair);
      boolean isPresent = pair.contains(5);
      System.out.println("5 is present: " + isPresent);
      List<Integer> list = new ArrayList<>();
      list.add(1);
      list.add(2);
      Triplet<Integer,Integer, String> triplet = pair.add("Test");
      System.out.println(triplet);
      Integer value = pair.getValue0();
      System.out.println(value);
      Unit<Integer> unit = pair.removeFrom0();
      System.out.println(unit);
      Pair<Integer, Integer> pair1 = Pair.fromCollection(list);   
      System.out.println(pair1);
   }
}

Verify the result

Compile the classes using javac compiler as follows −

C:JavaTuples>javac -cp javatuples-1.2.jar ./com/tutorialspoint/TupleTester.java

Now run the TupleTester to see the result −

C:JavaTuples>java  -cp .;javatuples-1.2.jar com.tutorialspoint.TupleTester

Output

Verify the Output

[5, 6]
5 is present: true
[5, 6, Test]
5
[6]
[1, 2]

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