JavaTuples - KeyValue Class-alljchome-开发者的教程家园

JavaTuples Tutorial

Selected Reading

JavaTuples - KeyValue Class

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 −

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