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From Matt Kendall <matt_kend...@iname.com>
Subject Re: [betwixt][SOLVED] Array of java.io.File objects.
Date Thu, 17 Nov 2005 16:08:58 GMT
It's always a good idea to take breaks during problem solving, I found
this solution in about thirty minutes this morning. The answer wound
up being quite simple (as I knew it should be). Posting for posterity:

For output, use a .betwixt file to suppress the majority of the File
object's properties:

<info>
	<element name="File">
		<attribute name="absolutePath" property="absolutePath"/>
	</element>
</info>

For input, add a custom creator the the BeanCreationChain (I did so by
using a BeanCreationList) that uses the absolutePath attribute to
return a file object, like so:

public class FileCreator implements ChainedBeanCreator {
	public Object create(ElementMapping mapping, ReadContext context,
			BeanCreationChain chain) {
		if (File.class.equals(mapping.getType())) {
			return new File(mapping.getAttributes().getValue("absolutePath"));
		}
		return chain.create(mapping, context);
	}
}

This kind of pattern *should* work for any complex object that you can
easily construct using one or more of its properties.

Matt

On 11/16/05, Matt Kendall <matt_kendall@iname.com> wrote:
> I've been tearing my hair out on this all afternoon. I've tried
> configuring Betwixt in way too many different ways to list them all
> here, so instead I'll just ask: what's the best way to handle the File
> object, specifically an array of file objects? I would like the
> following code to print out "2 == 2".
>
> public class FileTest {
>         private File[] files;
>
>         public File[] getFiles() {
>                 return files;
>         }
>
>         public void setFiles(File[] files) {
>                 this.files = files;
>         }
>
>         public static void main(String[] args) {
>                 FileTest test = new FileTest();
>
>                 test.setFiles(new File[] { new File("a.txt"), new File("b.txt") });
>
>                 try {
>                         BeanWriter writer = new BeanWriter(new FileWriter("ftout.xml"));
>                         writer.enablePrettyPrint();
>                         writer.write(test);
>                         writer.flush();
>                         writer.close();
>
>                         BeanReader reader = new BeanReader();
>                         reader.registerBeanClass(FileTest.class);
>                         test = (FileTest) reader.parse("ftout.xml");
>
>                         System.out.println("2 == " + test.getFiles().length);
>                 } catch (Exception e) {
>                         e.printStackTrace();
>                 }
>
>         }
>
> }
>
> I apologize if this question is too vague, but I've created so many
> mappers, converters, chains, etc. that enumerating all of them is much
> more complicated than simply understanding what I want from the
> following code.
>
> Oh, and the one solution I cannot employ is to rewrite the bean that I
> need to convert to XML. I didn't write it so I cannot change it.
>
> Thanks!
> Matt
>

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