I've tinkered with this, but there are definite limitations. I saw in Chuck Cavaness' book where he put a value or domain object as the sole property inside a form. In the JSPs he references it as form.bean.blahblahblah. I thought this meant I wouldn't have to dumb-down my forms. Well, as you've seen, BeanUtils.copyProperties() won't copy when it doesn't recognize the target class. You can create a Converter to handle some of these situations. I created an AbstractConverter class that has abstract getToClass() and getFromClass() methods. My convert() implementation just uses getToClass() to create an approriate target object (using Class.newInstance()), then calls BeanUtils.copyProperties on it. For simple situations, this works really well. However, there are some limitations. First, you can't have circular references because there's no mechanism in place to note whether the copying of a given object is already in progress. You'll get a StackOverflowError. I think I know how to get around this but it's pretty invasive. Second, you can't copy properties that are of the same type as the containing object easily. You'd have to duplicate a lot (all?) of the functionality of copyProperties(). Third, the contents of collections are a problem because you won't know what type the contents of the new collectin should be, unless you add some other facility for figuring this out (like "given value object type X, convert to domain object type Y." This is the opposite of how the Converters work now.) Finally, if you're copying from a persistent object that uses some form of pointer swizzling to a value object, you've opened a whole new can of worms.
I don't know what my fallabck solution is exactly. I think I might pick a few limitations and live with them for now. john -----Original Message----- From: Molitor, Stephen [mailto:[EMAIL PROTECTED]] Sent: Tuesday, January 28, 2003 8:30 AM To: 'Struts Users Mailing List' Cc: Ramarao, Nagaraj; Nair, Pramod Subject: Copying 'nested' properties from Dyna form to beans What's the best way to copy 'nested' form property values to Java beans? For example, let's say I a 'Person' bean, which contains a nested 'Name' bean, like this: class Name { String getFirstName() {...} void setFirstName(String firstName) {...} String getLastName() {...} void setLastName(String lastName) {...} } class Person { Name getName() {...} void setName(Name name) {...} String getZip() {...} void setZip(String zip) {...} } In the Person class, 'zip' is a top level property, but firstName and lastName are nested properties of the name property. I'd like to set up my validation.xml form element something like this: <form name="personForm"> <field property="name.firstName"/> <field property="name.lastName"/> <field property="zip"/> </form> Or, can I / should I nest form elements? Finally, what I'd like to do is use BeanUtils.copyProperties, or whatever, to copy from the dyna bean to the Person bean: BeanUtils.copyProperties(person, form); It would be cool if copyProperties would know to copy the name.firstName form element to person.getName().setFirstName(...). What's the best way to do something like this, to copy 'nested' properties transparently in one method call? Thanks! Steve --------------------------------------------------------------------- To unsubscribe, e-mail: [EMAIL PROTECTED] For additional commands, e-mail: [EMAIL PROTECTED]
