// Two .java files in one.

// Simple connection record for Base example
// By RP Futrelle, 5/11/01

/**
 * Simple record with the connected numbers, mode,
 * and countdown fields. No get/set methods are used
 * since this is a record with advertised, 
 * public instance variables.
 */

public class Connection {

    public int caller, called, mode, countdown;

    Connection(int caller, int called, int mode, int countdown) {
	this.caller = caller;
	this.called = called;
	this.mode = mode;
	this.countdown = countdown;
    }
    
    Connection(int caller, int called, int mode) {
	this.caller = caller;
	this.called = called;
	this.mode = mode;
    }

    public String toString() {
	return "Caller " + caller +
	    "  Called " + called +
	    "  Mode " + mode +
	    "  Countdown " + countdown;

    }

}

// Simple Base example
// By RP Futrelle, 5/11/01


import java.util.*; // includes Iterator (for Vectors)

/** 
 * This class illustrates use of the Connection record,
 * creating and managing a set of such records,
 * accessing, adding and removing items, and modular
 * code using a modular design with various private methods.
 * Uses an iterator.
 */
 
// for Iterator, see here,
// http://java.sun.com/docs/books/tutorial/collections/interfaces/collection.html
 
public class Base {

    Vector  connections;
    Connection c;

    static Connection cn;
    static Base b;

    static int DEAD = 0;
    static int PAGING = 1;

    public static void main(String[] args){

	b = new Base();

	b.connections.add(new Connection(1,2,DEAD,0));
	b.connections.add(new Connection(3,4,DEAD,0));
	b.connections.add(new Connection(5,6,DEAD,0));
	b.connections.add(new Connection(7,8,PAGING,0));

	System.out.println(b.toString());

	b.killConnections();

	System.out.println(b.toString());

	b.handlePage();
    }

    Base() {
	connections = new Vector();
    }

    /**
     * Processes only those connectdion records indicating an
     * attempt to page a phone.
     */
    private void handlePage(){
	for (Iterator cIt = connections.iterator();cIt.hasNext();) {
	    c = (Connection) cIt.next();
	    if ( c.mode == PAGING )
		o("Found a Paging connection record");
	}

    } // handlePage()

    /**
     * For demo purposes:  Remove all "dead" connections.
     */
    private void killConnections() {
	for (Iterator cIt = connections.iterator();cIt.hasNext();) {
	    c = (Connection) cIt.next();
	    if ( c.mode == DEAD ) {
		cIt.remove();
		o("Removed a dead connection record");
	    }
	}

    } // killConnections()
    
    /**
     * Utility for standard output.
     */
    private void o(String s) {
	System.out.println(s);
    }

    public String toString() {
	String s = "";

	for (Iterator cIt = connections.iterator();cIt.hasNext();) {
	    s += ((Connection)cIt.next()).toString() + "\n";
	}
	return s;
    } 
}

/* Output from the above:

Caller 1  Called 2  Mode 0  Countdown 0
Caller 3  Called 4  Mode 0  Countdown 0
Caller 5  Called 6  Mode 0  Countdown 0
Caller 7  Called 8  Mode 1  Countdown 0

Removed a dead connection record
Removed a dead connection record
Removed a dead connection record
Caller 7  Called 8  Mode 1  Countdown 0

Found a Paging connection record

*/