[jdom-interest] Converting Java Objects to XML

[Frank Sauer]

but you mentioned this:

> into an application that doesn't have access to the original classes.

So what you tell me is, that with just an XML file I get from you
and no classes that are being represented by your data, I can get
instances of the objects represented in your XML with the same
behavior they had when you created the XML representation?
how does that work? 

The only way that might work is by including a Base64 encoded 
bytearray with all the bytecodes and a custom class loader.....


Frank

-----Original Message-----
From: Jeff Martin [mailto:jeff at reportmill.com]
Sent: Friday, October 11, 2002 6:06 PM
To: Frank Sauer
Cc: jdom-interest at jdom.org
Subject: Re: [jdom-interest] Converting Java Objects to XML


Well the Caster guys are doing the whole Object-Relational mapping 
thing, which is a much more ambitious project. However, in my research 
over the last few weeks I couldn't find a standard convention or 
library for writing out an object representation for an object graph 
(the JSX library came the closest, but it writes out only "settable" 
attributes - and blew my data up by an order of magnitude). I was 
surprised, because this seems crucial to using XML as an interchange 
format, rather than a persistence format (where the consumer could 
count on having the archived classes available).

My class provides a convention and implementation of writing out an 
object graph in a concise, but fully descriptive way (including 
circular references, value typing, etc.). The RMSchema element is a 
simple list of Entities (with their properties). I have an RMXMLReader 
class that easily reads this file and constructs a simple hierarchy of 
Maps/Lists/Strings/Numbers/Dates, but right now it depends on a bit of 
code from the rest of my project. It will take about a day to make it 
stand-alone, like RMXMLWriter. I'll have to see if there's any interest 
in this before I spend the time.

Re: Your last question about a public method which calls a private 
method: this isn't an obstacle - my class uses basic Java Reflection - 
if they chain a call like that, it has no bearning. My object sees only 
the result from the top-level public method, and represents that 
member/value.

jeff

On Friday, October 11, 2002, at 04:47  PM, Frank Sauer wrote:

> You call that less grand???
> How do you plan on representing the public behavior in a way
> that it can be reconstructed in a runnable fashion? What if
> a public methods calls a private method that's not included?
>
> Frank
>
> -----Original Message-----
> From: Jeff Martin [mailto:jeff at reportmill.com]
> Sent: Friday, October 11, 2002 4:27 PM
> To: Grinvald, Edward
> Cc: jdom-interest at jdom.org
> Subject: Re: [jdom-interest] Converting Java Objects to XML
>
>
> Well my goal is much less grand and slightly different. This class
> doesn't create an "archive" of an object graph, it creates a
> "representation" - which includes all public methods (including any
> derived business logic methods), not just values from getter/setter
> methods. This is great for importing a description of an object graph
> into an application that doesn't have access to the original classes.
>
> Also, it's a single class file - no setup and configuration necessary.
> It just turns objects to XML in fell swoop.
>
> jeff