import java.io.ioexception;

import java.io.printstream;

import java.util.hashmap;

import java.util.iterator;

import java.util.linkedlist;

import java.util.list;

import java.util.map;

public class genericstester {

  public void testtypesafemaps(printstream out) throws ioexception {

    map<integer, integer> squares = new hashmap<integer, integer>();

    for (int i=0; i<100; i++) {

      squares.put(i, i*i);

    }

    for (int i=0; i<10; i++) {

      int n = i*3;

      out.println(n + "的平方是" + squares.get(n));

    }

  }

//测试安全的链表

  public void testtypesafelists(printstream out) throws ioexception {

    list listofstrings = getlistofstrings();

    for (iterator i = listofstrings.iterator(); i.hasnext(); ) {

      string item = (string)i.next();

    }

    list<string> onlystrings = new linkedlist<string>();

    onlystrings.add("legal addition");

    /**

     * uncomment these two lines for an error

    onlystrings.add(new stringbuilder("illegal addition"));

    onlystrings.add(25);

     */

  }

  public void testtypesafeiterators(printstream out) throws ioexception {   //初始化迭代

    list<string> listofstrings = new linkedlist<string>();

    listofstrings.add("happy");

    listofstrings.add("birthday");

    listofstrings.add("to");

    listofstrings.add("you");

    for (iterator<string> i = listofstrings.iterator(); i.hasnext();) {

      string s = i.next();

      out.println(s);

    }

    printlistofstrings(getlistofstrings(), out);

  }

//得到普通链表

  private list getlist() {

    list list = new linkedlist();

    list.add(3);

    list.add("blind");

    list.add("mice");

    return list;

  } 

  //得到安全的链表

  private list<string> getlistofstrings() {

    list<string> list = new linkedlist<string>();

    list.add("hello");

    list.add("world");

    list.add("how");

    list.add("are");

    list.add("you?");

    return list;

  }

  public void testtypesafereturnvalues(printstream out) throws ioexception {

    list<string> strings = getlistofstrings();

    for (string s : strings) {

      out.println(s);

    }

  } //接受参数化类型的链表

  private void printlistofstrings(list<string> list, printstream out)

    throws ioexception {

    for (iterator<string> i = list.iterator(); i.hasnext(); ) {

      out.println(i.next());

    }

  }

  public void printlist(list<?> list, printstream out) throws ioexception {    for (iterator<?> i = list.iterator(); i.hasnext(); ) {

      out.println(i.next().tostring());

    }

  }

  public static void main(string[] args) {

    genericstester tester = new genericstester();

    try {

      tester.testtypesafelists(system.out);

      tester.testtypesafemaps(system.out);

      tester.testtypesafeiterators(system.out);

      tester.testtypesafereturnvalues(system.out);

      list<integer> ints = new linkedlist<integer>();

      ints.add(1);

      ints.add(2);

      ints.add(3);

      tester.printlist(ints, system.out);

    } catch (exception e) {

      e.printstacktrace();

    }

  }

}