JavaTuples - KeyValue Class


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Introduction

The org.javatuples.KeyValue class represents a Tuple with two elements with positions 0 and 1 renamed as "key" and "value", respectively.

Class Declaration

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

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

Class Constructor

Sr.No. Constructor & Description
1

KeyValue(A value0, B value1)

This creates a KeyValue Tuple.

Class Methods

Sr.No. Method & Description
1

static <X> KeyValue<X,X> fromArray(X[] array)

Create tuple from array.

2

static <X> KeyValue<X,X> fromCollection(Collection<X> collection)

Create tuple from collection.

3

static <X> KeyValue<X,X> fromIterable(Iterable<X> iterable)

Create tuple from iterable.

4

static <X> KeyValue<X,X> fromIterable(Iterable<X> iterable, int index)

Create tuple from iterable, starting from the specified index.

5

A getKey()

Return the key.

6

int getSize()

Return the size of the tuple.

7

A getValue()

Returns the value of the tuple.

8

<X> KeyValue<X,B> setKey(X key)

set the label and return the tuple.

9

<X> KeyValue<A,Y> setValue(Y value)

set the value and return the tuple.

10

static <A,B> KeyValue<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 KeyValue 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.KeyValue;
public class TupleTester {
   public static void main(String args[]){
      KeyValue<Integer, Integer> keyValue = KeyValue.with(5,6);
      System.out.println(keyValue);
      List<Integer> list = new ArrayList<>();
      list.add(1);
      list.add(2);
      Integer key = KeyValue.getKey();
      System.out.println(key);
      Integer value = KeyValue.getValue();
      System.out.println(value);
      KeyValue<Integer, Integer> keyValue1 = KeyValue.fromCollection(list);   
      System.out.println(keyValue1);
   }
}

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
6
[1, 2]
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