doc/released/examples/telecom/Connection.java

/*

Copyright (c) Xerox Corporation 1998-2002.  All rights reserved.

Use and copying of this software and preparation of derivative works based
upon this software are permitted.  Any distribution of this software or
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laws.
 
This software is made available AS IS, and Xerox Corporation makes no warranty
about the software, its performance or its conformity to any specification.

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*/
package telecom;

/**
 * Connections are circuits between customers
 * There are two kinds: local and long distance
 * see subclasses at the end of this file.
 */
public abstract class Connection {

    public static final int PENDING = 0;
    public static final int COMPLETE = 1;
    public static final int DROPPED = 2;

    Customer caller, receiver;
    private int state = PENDING;

    /**
     * Creatte a new Connection between a and b
     */
    Connection(Customer a, Customer b) {
        this.caller = a;
        this.receiver = b;
    }

    /**
     * what is the state of the connection?
     */
    public int getState(){
	return state;
    }

    /**
     * get the customer who initiated this connection
     */
    public Customer getCaller() { return caller; }

    /**
     * get the customer who received this connection
     */
    public Customer getReceiver() { return receiver; }

    /**
     * Called when a call is picked up.  This means the b side has picked up
     * and the connection should now complete itself and start passing data.
     */
    void complete() {
        state = COMPLETE;
        System.out.println("connection completed");
    }

    /**
     * Called when the connection is dropped from a call.  Is intended to
     * free up any resources the connection was consuming.
     */
    void drop() {
	state = DROPPED;
        System.out.println("connection dropped");
    }

    /**
     * Is customer c connected by this connection?
     */
    public boolean connects(Customer c){
	return (caller == c || receiver == c);
    }

}