COM1204 Object-Oriented Design -- Spring 2001
Java source code, three class files, for a simple demonstration project.
Created 3/31/2001 by Professor R. P. Futrelle, Northeastern University.

Course pages at:  http://www.ccs.neu.edu/home/futrelle/teaching/com1204sp2001/

Pages for this demo at: http://www.ccs.neu.edu/home/futrelle/teaching/com1204sp2001/demo1/

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File Phone.java --

/**
 * Class Phone in demo1 <br>
 * Receives a dial from a User.
 *
 * @author RP Futrelle
 * @version 1.0
 */
public class Phone {

    public static void Main(String[] args) {
        // empty for now
    }

    /**
     * Number being dialed
     */
    public int numberDialed = -1;

    /**
     * For now, step() doesn't try to handle calls.
     */
    public void step() {
        System.out.println("Step Phone: My number dialed is " +
                           numberDialed);
    }

    /**
     * Important access function. <br> Phone can be dialed.
     * @param phoneNumber The number dialed by the user.
     */
    public void dial(int phoneNum) {
        numberDialed = phoneNum;
        System.out.println("My owner dialed me with " + phoneNum);
    }
}
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File Simulation.java --

/**
 * Class Simulation
 * Sets up and runs the phone system.
 *
 * @author RP Futrelle
 * @version 1.0
 */
public class Simulation {

    /**
     * This initializes the system and steps it a few times.
     */
    public static void main(String[] args) {
        Simulation mainSim = new Simulation(); // a singleton
        mainSim.init(); // Initialize simulation
        mainSim.run(3); // Step all 3 times.
    }

    /**
     * For now, simply creates one user and one phone.
     * Later there will be collections of users and phones.
     */
    public void init() {
        onlyPhone = new Phone();
        onlyUser = new User();
        onlyUser.giveItPhone(onlyPhone); // user needs a phone
    }

    public Phone onlyPhone;

    public User onlyUser;

    /**
     * Steps all system components multiple times.
     * @param nTimes The number of cycles the system is stepped.
     */
    public void run(int nTimes) {
        for(int i=0; i < nTimes; i++){
            onlyUser.step();
            onlyPhone.step();
        }
    }
}
***********************************************************************

File User.java --

/**
 * Class User in demo1 <br>
 * Will dial a call when stepped. <br>
 * Must be given a phone first.
 *
 * @author RP Futrelle
 * @version 1.0
 */
public class User {

    public static void Main(String[] args) {
        // empty for now
    }

    /**
     * This is the user's phone.
     */
    public Phone myPhone;

    /**
     * Use this to assign a phone to this user.
     */
    public void giveItPhone(Phone p) {
        myPhone = p;
    }

    /**
     * For now, step() just dials a number.
     */
    public void step() {
        System.out.println("Step User: I will dial " + 333);
        myPhone.dial(333);

    }
}