chapter21n2.java

JAVA源代码程序aashjkjhkjhkjhjkhkj

/**
 *
 * demonstration of Hashtable
 *
 * Written by: Roger Garside
 *
 * First Written: 5/Feb/97
 * Last Rewritten: 5/Feb/97
 *
 */

import java.io.* ;
import java.util.* ;

class PersonDates
    {
    private int birth, death ;

    /**
     *
     * constructor
     *
     */

    public PersonDates (int b, int d)
	{
	birth = b ;
	death = d ;
	} // end of constructor method

    public int getBirthDate()
	{
	return birth ;
	} // end of method getBirthDate

    public int getDeathDate()
	{
	return death ;
	} // end of method getDeathDate
    } // end of class PersonDates

public class Chapter21n2
    {
    public static void main(String[] args) throws Exception
	{
	Hashtable t = new Hashtable() ;
	t.put("shakespeare", new PersonDates(1564, 1616)) ;
	t.put("austen", new PersonDates(1775, 1817)) ;
	t.put("dickens", new PersonDates(1812, 1870)) ;
	t.put("trollope", new PersonDates(1815, 1882)) ;
	t.put("bronte", new PersonDates(1818, 1848)) ;
	t.put("eliot", new PersonDates(1819, 1880)) ;
	PersonDates result = (PersonDates) t.put("bronte",
				new PersonDates(1816, 1855)) ;
	if (result != null)
	    System.err.println("duplicate information") ;
	System.err.println() ;

	System.err.print("type author's name ") ;
	System.err.flush() ;
	BufferedReader din = new BufferedReader(new
				InputStreamReader(System.in)) ;
	String name = din.readLine().trim() ;
	PersonDates p = (PersonDates) t.get(name) ;
	if (p == null)
	    System.err.println("I have no information about " + name) ;
        else
	    System.err.println(name + " was born in " + p.getBirthDate() +
			" and died in " + p.getDeathDate()) ;
	System.err.println() ;

        Enumeration hashElements = t.elements() ;
        Enumeration hashKeys = t.keys() ;
	while (hashKeys.hasMoreElements())
	    {
	    System.err.print(hashKeys.nextElement()) ;
	    PersonDates p1 = (PersonDates) hashElements.nextElement() ;
	    System.err.println(" was born in " + p1.getBirthDate()
	    		+ " and died in " + p1.getDeathDate()) ;
	    }
	} // end of method main
    } // end of class Chapter21n2