Java Program to implement Associate Array

This is a Java Program to implement Associate Array. An associative array, map, symbol table, or dictionary is an abstract data type composed of a collection of (key, value) pairs, such that each possible key appears at most once in the collection.

Here is the source code of the Java Program to implement Associate Array. The Java program is successfully compiled and run on a Windows system. The program output is also shown below.

/**
 ** Java Program to implement Associate Array
 **/
 
import java.util.Scanner;
import java.util.HashMap;
 
/** class AssociateArray */
class AssociateArray
{
    private HashMap<String, String> keyVal;   
 
    /** constructor **/
    public AssociateArray()
    {
        keyVal = new HashMap<String, String>();        
    }    
    /** function to clear **/
    public void clear()
    {
        keyVal.clear();        
    }
    /** function to get size **/
    public int size()
    {
        return keyVal.size();
    }   
    /** function to insert element **/
    public void insert(String key, String val)
    {
        keyVal.put(key, val);        
    }    
    /** function to get element **/
    public String get(String ele)
    {
        return keyVal.get(ele);        
    }      
    /** function to remove element **/
    public void remove(String key)
    {
        keyVal.remove(key);              
    } 
    /** function to modify **/
    public void modify(String key, String val)
    {
        keyVal.put(key, val);        
    }        
}
 
/** Class AssociateArrayTest **/
public class AssociateArrayTest
{
    public static void main(String[] args)
    {
        Scanner scan = new Scanner(System.in);
        System.out.println("Associate Array Test\n");   
 
        AssociateArray aa = new AssociateArray();
 
        char ch;
        /*  Perform Associate Array operations */
        do    
        {
            System.out.println("\nAssociate Array <String, String> Operations\n");
            System.out.println("1. put ");
            System.out.println("2. get");
            System.out.println("3. remove");
            System.out.println("4. modify");
            System.out.println("5. clear");
            System.out.println("6. size");
 
            int choice = scan.nextInt();            
            switch (choice) 
            {
            case 1 : 
                System.out.println("Enter key and value");
                aa.insert(scan.next(), scan.next() );                     
                break;                          
            case 2 : 
                System.out.println("Enter element");
                String ele = scan.next();
                String str = aa.get(ele);
                if (str != null)
                    System.out.println("Result : "+ str);
                else
                    System.out.println("\nError : Not found\n");  
                break;        
            case 3 : 
                System.out.println("\nEnter key to be removed");
                aa.remove(scan.next() );
                break; 
            case 4 : 
                System.out.println("\nEnter key, value to be modified");
                aa.modify(scan.next(), scan.next() );  
                break;                                                        
            case 5 : 
                System.out.println("\nAssociate Array Cleared");
                aa.clear();
                break;    
            case 6 : 
                System.out.println("\nSize = "+ aa.size() );
                break;         
            default : 
                System.out.println("Wrong Entry \n ");
                break;   
            }    
 
            System.out.println("\nDo you want to continue (Type y or n) \n");
            ch = scan.next().charAt(0);                        
        } while (ch == 'Y'|| ch == 'y');            
    }
}

Associate Array Test
 
 
Associate Array <String, String> Operations
 
1. put
2. get
3. remove
4. modify
5. clear
6. size
1
Enter key and value
fruit mango
 
Do you want to continue (Type y or n)
 
y
 
Associate Array <String, String> Operations
 
1. put
2. get
3. remove
4. modify
5. clear
6. size
1
Enter key and value
vegetable tomato
 
Do you want to continue (Type y or n)
 
y
 
Associate Array <String, String> Operations
 
1. put
2. get
3. remove
4. modify
5. clear
6. size
1
Enter key and value
drink water
 
Do you want to continue (Type y or n)
 
y
 
Associate Array <String, String> Operations
 
1. put
2. get
3. remove
4. modify
5. clear
6. size
2
Enter element
drink
Result : water
 
Do you want to continue (Type y or n)
 
y
 
Associate Array <String, String> Operations
 
1. put
2. get
3. remove
4. modify
5. clear
6. size
2
Enter element
fruit
Result : mango
 
Do you want to continue (Type y or n)
 
y
 
Associate Array <String, String> Operations
 
1. put
2. get
3. remove
4. modify
5. clear
6. size
4
 
Enter key, value to be modified
fruit apple
 
Do you want to continue (Type y or n)
 
y
 
Associate Array <String, String> Operations
 
1. put
2. get
3. remove
4. modify
5. clear
6. size
2
Enter element
fruit
Result : apple
 
Do you want to continue (Type y or n)
 
y
 
Associate Array <String, String> Operations
 
1. put
2. get
3. remove
4. modify
5. clear
6. size
6
 
Size = 3
 
Do you want to continue (Type y or n)
 
y
 
Associate Array <String, String> Operations
 
1. put
2. get
3. remove
4. modify
5. clear
6. size
3
 
Enter key to be removed
fruit
 
Do you want to continue (Type y or n)
 
y
 
Associate Array <String, String> Operations
 
1. put
2. get
3. remove
4. modify
5. clear
6. size
2
Enter element
fruit
 
Error : Not found
 
 
Do you want to continue (Type y or n)
 
y
 
Associate Array <String, String> Operations
 
1. put
2. get
3. remove
4. modify
5. clear
6. size
5
 
Associate Array Cleared
 
Do you want to continue (Type y or n)
 
y
 
Associate Array <String, String> Operations
 
1. put
2. get
3. remove
4. modify
5. clear
6. size
6
 
Size = 0
 
Do you want to continue (Type y or n)
 
n