Recently, I’ve built the client side of a J2EE Transfer Object pattern implementation and it composes a number of value objects. I was going to shape the VO’s like in Darron Schall’s Book VO used in his “Convert Generic Objects into Class Instances” article (good read I might add). The VO consists of an object with public attributes and nothing else.

public class Book
{
public var title:String;
public var pageCount:int;
public var publishedDate:Date;
public var inLibrary:Boolean;

// Just for kicks...
public var random:*;
} // end class

I was contemplating whether to use getter/setter methods using the get & set keywords. It would allow me to parse information that was coming in as Strings but return it in the type it was needed.

A little bit of net research led me to this nice article that using get methods and set methods can add more flexibility in the future.

1) Get methods can return a default value if it’s undefined/null

2) Get methods can be used to trigger lazy instantiation: Why create instantiate the object of a linked attribute at the time of the VO’s initialization when you can do it at the time you need?

3) Set methods can perform validation: This was the main reason why I considered getter/setters with VO’s.

4) You can have multiple getters for the same private attribute: Very cool, didn’t realize how handy this could be.