XOM API for Processing XML with Java

[jcowan AT reutershealth.com]

Elliotte Harold - java FAQ scripsit:

> public Document build(String systemID);
> public Document build(String document, String baseURI);
> 
> Yesterday it occurred to me that the second one is backwards. In keeping 
> with the general principle of overloading methods by adding successive 
> arguments (Does anyone have a reference on that?)

I think nobody has documented the design pattern "Argument Order" before,
but the idea is to push optional arguments to the right.  Overloading is how
Java does optional arguments.

> I think these should be:
> 
> public Document build(String systemID);
> public Document build(String baseURI, String document);

No, I think you have it correct already.  Conceptually, the build()
multimethod takes two arguments, a source and an optional base URI.
Currently, the source can be a File, an InputStream, a Reader, a system
ID (represented as a String), or a String.  Since the last two have
the same representation, you're forced to make the base URI prohibited
when the source is a system ID (which is reasonable) and required when
the source is a String (which is also reasonable, as there is no way to
deduce the base URI of a String).  There is no obvious reason, though,
why a base URI can't be set when the source is a File.

That said, it's not very clear to me why you want to support File
or String as sources anyhow; it's soooo trivial to wrap the File in
a FileInputStream and the String in a StringReader.  It seems to me
like clutter.  If you want, mention FileInputStream and StringReader in the
documentation.

> Then, maybe one of the arguments should be renamed; e.g.

System IDs aren't base URIs, though they have the same syntax.

-- 
John Cowan  www.ccil.org/~cowan  www.reutershealth.com  
jcowan AT reutershealth.com
[T]here is a Darwinian explanation for the refusal to accept Darwin.
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