The Vehicle Registration Redone�

With this new framework component in place, our Vehicle registration configuration file will have a new look. Listing 3 presents the new form bean configurations.

<form-bean name=" vehicleCommonForm " type="org.apache.struts.action.DynaActionForm">
     <form-property name="registrationNumber" type="java.lang.String"/>
     <form-property name="maker" type="java.lang.String"/>
     <form-property name="modelNumber" type="java.lang.Integer"/>
</form-bean>

<form-bean name="CarForm" type=" custom.struts. CustomDynaForm ">

     <form-property name="engineSize" type="java.lang.Integer"/>
     <form-property name="noOfDoors" type="java.lang.Integer"/>
     <form-property name="insuranceGroup" type="java.lang.String"/>

     <form-property name="includes" type="java.lang.String" initial=”vehicleCommonForm”/>

 </form-bean>

 <form-bean name="ShipForm" type=" custom.struts. CustomDynaForm ">

     <form-property name="tonnage" type="java.lang.Integer"/>
     <form-property name="numberOfBoilers" type="java.lang.Integer"/>
     <form-property name="shipUsedAs" type="java.lang.String"/>

     <form-property name="includes" type="java.lang.String" initial=”vehicleCommonForm”/>

 </form-bean>

Listing 3: The changed form bean configuration file

In this new model, we have reduced the duplication of the data across form beans. Next we tested this new model against our application and voila it worked fine!

Conclusion�

This new model helped us model the inheritance relationship that exists in the domain model of the Struts layer. This definitely is more manageable and a more flexible solution. If the super class in the domain model needs to hold some additional data, it is only in one place that we need to add it to. For a large scale system where we are defining hundreds of different types of Vehicles, this could be a serious maintenance gain. Also to us the solution looked cleaner. To achieve the best out of it, it will be a wise idea to also use composite pattern in declaring the JSP. One can think of writing a single vehicleCommon.jsp and include it in carForm.jsp and shipForm.jsp. Hope this article will help you, if you are facing similar problems. Please feel free to write to me with your ideas. Happy Struts !

Samudra Gupta has six years of Java related application development experience. He has been involved in various research based projects in Java including e-commerece based and application design and development projects. He is based in the United Kingdom. In his free time, he is a columnist in different Java Magazines and Journals and loves to play contract bridge.

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