package com.tutorialspoint;

import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;

public class GenericsTester {
   public static void main(String[] args) {
      Box box = new Box();
      box.add(Integer.valueOf(10),"Hello World");
      System.out.printf("Integer Value :%d\n", box.getFirst());
      System.out.printf("String Value :%s\n", box.getSecond());

      Pair pair = new Pair(); 
      pair.addKeyValue("1", Integer.valueOf(10));
      System.out.printf("(Pair)Integer Value :%d\n", pair.getValue("1"));

      CustomList list = new CustomList();
      list.addItem(box);
      System.out.printf("(CustomList)Integer Value :%d\n", list.getItem(0).getFirst());
   }
}

class Box {
   private T t;
   private S s;

   public void add(T t, S s) {
      this.t = t;
      this.s = s;
   }

   public T getFirst() {
      return t;
   } 

   public S getSecond() {
      return s;
   } 
}

class Pair{
   private Map map = new HashMap();

   public void addKeyValue(K key, V value) {
      map.put(key, value);
   }

   public V getValue(K key) {
      return map.get(key);
   }
}

class CustomList{
   private List list = new ArrayList();

   public void addItem(E value) {
      list.add(value);
   }

   public E getItem(int index) {
      return list.get(index);
   }
}

Integer Value :10
String Value :Hello World
(Pair)Integer Value :10
(CustomList)Integer Value :10