hitime.java

《深入java虚拟机》一书的光盘

/*
* Copyright (c) 1997-1999 Bill Venners. All rights reserved.
*
* Source code file from the book "Inside the Java 2 Virtual Machine,"
* by Bill Venners, published by McGraw-Hill, 1999, ISBN: 0-07-135093-4. 
*
* This source file may not be copied, modified, or redistributed
* EXCEPT as allowed by the following statements: You may freely use
* this file for your own work, including modifications and distribution
* in compiled (class files, native executable, etc.) form only. You may
* not copy and distribute this file. You may not remove this copyright
* notice. You may not distribute modified versions of this source file.
* You may not use this file in printed media without the express
* permission of Bill Venners. 
*
* BILL VENNERS MAKES NO REPRESENTATIONS OR WARRANTIES ABOUT THE
* SUITABILITY OF THIS SOFTWARE, EITHER EXPRESS OR IMPLIED, INCLUDING
* BUT NOT LIMITED TO THE IMPLIED WARRANTIES OF MERCHANTABILITY, FITNESS
* FOR PARTICULAR PURPOSE, OR NON-INFRINGEMENT. BILL VENNERS SHALL NOT
* BE LIABLE FOR ANY DAMAGES SUFFERED BY A LICENSEE AS A RESULT OF
* USING, MODIFYING OR DISTRIBUTING THIS SOFTWARE OR ITS DERIVATIVES.
*/

// On CD-ROM in file linking/ex6/greeters/HiTime.java
import COM.artima.greeter.Greeter;
import java.util.Date;

public class HiTime implements Greeter {

    public void greet() {

        // Date's no-arg constructor initializes itself to the
        // current date and time
        Date date = new Date();
        int hours = date.getHours();

        // Some hours: midnight, 0; noon, 12; 11PM, 23;
        if (hours >= 4 && hours <= 11) {
            System.out.println("Good morning, world!");
        }
        else if (hours >= 12 && hours <= 16) {
            System.out.println("Good afternoon, world!");
        } 
        else if (hours >= 17 && hours <= 21) {
            System.out.println("Good evening, world!");
        } 
        else if (hours >= 22 || hours <= 3) {
            System.out.println("Good night, world!");
        }
        else {
            // This should never happen.
            System.out.println("Oh oh, the clock is broken, world!");
        }
    }
}