Design Patterns Java™ Workbook

Appendix B. Solutions

SOLUTION 17.2....................................................................................................................................

Here is one solution:

package com.oozinoz.check.canada;
import com.oozinoz.check.*;
public class CheckFactoryCanada extends CheckFactory
{
public BillingCheck createBillingCheck()
{
return new BillingCheckCanada();
}

public CreditCheck createCreditCheck()
{
if (isAgencyUp())
{
return new CreditCheckCanadaOnline();
}
else
{
return new CreditCheckOffline();
}
}

public ShippingCheck createShippingCheck()
{
return new ShippingCheckCanada();
}
}

Your solution should

• Have create- methods for each interface in com.oozinoz.check


• Have the proper interface for the return type of each create- method


• Return a CreditCheckOffline object if the agency is down

SOLUTION 17.3....................................................................................................................................

A version of CheckFactory.java that makes U.S. and Canada factories readily available
is:

package com.oozinoz.check;

import com.oozinoz.check.us.CheckFactoryUS;
import com.oozinoz.check.canada.CheckFactoryCanada;

public abstract class CheckFactory {
public static final CheckFactory US =
new CheckFactoryUS();

public static final CheckFactory CANADA =
new CheckFactoryCanada();

public abstract BillingCheck createBillingCheck();