cashdispenser.java

来自「含有uml的多个实例及实例的java源码。」· Java 代码 · 共 75 行

/*
 * ATM Example system - file CashDispenser.java
 *
 * copyright (c) 2001 - Russell C. Bjork
 *
 */
 
package atm.physical;

import banking.Money;
import simulation.Simulation;

/** Manager for the ATM's cash dispenser.  In a real ATM, this would 
 *  manage a physical device; in this simulation,  it uses classes 
 *  in package simulation to simulate the device.
 */
 
public class CashDispenser
{
    /** Constructor
     *
     *  @param log the log in which to record dispensing cash
     */
    public CashDispenser(Log log)
    {
        this.log = log;
        
        cashOnHand = new Money(0);
    }
    
    /** Set the amount of cash initially on hand 
     *
     *  @param initialCash the amount of money in the dispenser
     */
    public void setInitialCash(Money initialCash)
    {
        cashOnHand = initialCash;
    }
    
    /** See if there is enough cash on hand to satisfy a request
     *
     *  @param amount the amount of cash the customer wants
     *  @return true if at least this amount of money is available
     */
    public boolean checkCashOnHand(Money amount)
    {
        return amount.lessEqual(cashOnHand);
    }
    
    /** Dispense cash to a customer
     *
     *  @param amount the amount of cash to dispense
     *
     *  Precondition: amount is <= cash on hand
     */
    public void dispenseCash(Money amount)
    {
        cashOnHand.subtract(amount);
        
        Simulation.getInstance().dispenseCash(amount);
        
        // Log cash having been dispensed
        
        log.logCashDispensed(amount);
    }

    /** Log into which cash amounts dispensed will be recorded
     */ 
    private Log log;
    
    /** Current cash on hand
     */
    private Money cashOnHand;
}