Digester selecting wrong property setter method

["YAWN,MIKE (HP-PaloAlto,ex1)" <mi...@hp.com>]

Digester gurus,

I have certain properties within a bean which are represented as numeric
values.  However, these numeric values are an internal implementation detail
I don't really want to expose to users, so I'd rather have the bean
configured using meaningful text strings.

For example, consider a field indicating how to contact someone:

    private int preferredContact;
    public final static int PHONE = 1;
    public final static int EMAIL = 2;
    public int getPreferredContact() { return preferredContact; }
    public void setPreferredContact(int pc) { preferredContact = pc; }

Now, I would have expected that digester could not have set this field even
if I wanted to expose the numeric values, simply because XML contains text,
not integers.  So I altered this class to work with Digester by adding the
following method:

	public void setPreferredContact(String pc) {
		if (pc.equals("phone"))
			preferredContact = PHONE;
		else if (pc.equals("email"))
			preferredContact = EMAIL;
		else
			// log an error
	}

And XML input file contains (vastly simplified):
	<personInfo preferredContact="email" />

Now, when I run digester, my nice String-based setPreferredContact method is
ignored in favor of the one taking an int.  The int value comes in as zero,
not a legal value for the field and thus causing problems later.

Given that the parsed XML is a string value that doesn't even resemble an
int, and a setter method taking a String is provided, I would really expect
Digester to use the String variant, rather than go through ConvertUtils and
come up with a (seemingly random) integer value.  How can I force Digester
to select the interface I created specifically for its use?

Thanks,
Mike Yawn

Re: Digester selecting wrong property setter method

[robert burrell donkin <ro...@blueyonder.co.uk>]

(as has been pointed out by the previous posted, the reasons why the 
standard digester rules don't work is that java beans are not supposed to 
have overloaded setters.)

a more elegant solution to this problem might be to create a custom Rule 
which knows about your enums. if string-to-int enums are a common enough 
pattern, then maybe someone will volunteer to contribute a general 
implementation.

(i might even do so myself if there's enough demand from users...)

- robert

On Wednesday, December 11, 2002, at 07:25 PM, YAWN,MIKE (HP-PaloAlto,ex1) 
wrote:

> Digester gurus,
>
> I have certain properties within a bean which are represented as numeric
> values.  However, these numeric values are an internal implementation 
> detail
> I don't really want to expose to users, so I'd rather have the bean
> configured using meaningful text strings.
>
> For example, consider a field indicating how to contact someone:
>
>     private int preferredContact;
>     public final static int PHONE = 1;
>     public final static int EMAIL = 2;
>     public int getPreferredContact() { return preferredContact; }
>     public void setPreferredContact(int pc) { preferredContact = pc; }
>
> Now, I would have expected that digester could not have set this field 
> even
> if I wanted to expose the numeric values, simply because XML contains 
> text,
> not integers.  So I altered this class to work with Digester by adding the
> following method:
>
> 	public void setPreferredContact(String pc) {
> 		if (pc.equals("phone"))
> 			preferredContact = PHONE;
> 		else if (pc.equals("email"))
> 			preferredContact = EMAIL;
> 		else
> 			// log an error
> 	}
>
> And XML input file contains (vastly simplified):
> 	<personInfo preferredContact="email" />
>
> Now, when I run digester, my nice String-based setPreferredContact method 
> is
> ignored in favor of the one taking an int.  The int value comes in as 
> zero,
> not a legal value for the field and thus causing problems later.
>
> Given that the parsed XML is a string value that doesn't even resemble an
> int, and a setter method taking a String is provided, I would really 
> expect
> Digester to use the String variant, rather than go through ConvertUtils 
> and
> come up with a (seemingly random) integer value.  How can I force Digester
> to select the interface I created specifically for its use?
>
> Thanks,
> Mike Yawn
>
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