Mailing-List: contact commons-dev-help@jakarta.apache.org; run by ezmlm
Precedence: bulk
Reply-To: "Jakarta Commons Developers List" <commons-dev@jakarta.apache.org>
Date: 27 Aug 2004 09:37:55 -0000
Message-ID: <20040827093755.14193.qmail@nagoya.betaversion.org>
From: bugzilla@apache.org
To: commons-dev@jakarta.apache.org
Cc: 
Subject: DO NOT REPLY [Bug 30545]  -
    [configuration] ConfigurationDynaBean

DO NOT REPLY TO THIS EMAIL, BUT PLEASE POST YOUR BUG 
RELATED COMMENTS THROUGH THE WEB INTERFACE AVAILABLE AT
<http://issues.apache.org/bugzilla/show_bug.cgi?id=30545>.
ANY REPLY MADE TO THIS MESSAGE WILL NOT BE COLLECTED AND 
INSERTED IN THE BUG DATABASE.

http://issues.apache.org/bugzilla/show_bug.cgi?id=30545

[configuration] ConfigurationDynaBean


------- Additional Comments From ricardo.gladwell@btinternet.com  2004-08-27 09:37 -------
I have a question about the behavior of ConfigurationDynaBean.
I'm not sure what the intended behavior should be, but looking at the
code in the CVS repository makes me think the intent is different from
the current behavior. However, it appears this is fairly new code, so
I don't know if the problem is in the code behavior or if I am just
misinterpreting the intent from the code.

In looking at the code, it appears the intent was for the get method
to throw an IllegalArgumentException in the case where the desired
property does not exist in the backing Configuration instance. This
would cause the method to meet the specification of get in the
DynaBean interface. However, get only throws the exception if the
specified name is null. If the name is non-null but does not exist,
then an empty ConfigurationDynaBean is returned.

The reason for this is in the call to configuration.subset in the get
method. The relevant code is shown below (this is version 1.2 from the
CVS repository):

        // get configuration property
        Object result = configuration.getProperty(name);
        if(result == null && name != null) {
            // otherwise attempt to create bean from configuration subset
            Configuration subset = configuration.subset(name);
            if(subset != null)
                result = new ConfigurationDynaBean(configuration.subset(name));
        }

If the extracted subset is not null, then a new ConfigurationDynaBean
is constructed from that subset. However, I don't think
Configuration.subset ever returns null. If no properties from the
configuration begin with the specified prefix, then the return value
from subset is an empty Configuration, not null (this is true even if
the prefix argument is null). Therefore, the "if(subset != null)" test
always succeeds in the above code, and result is always set to a new
ConfigurationDynaBean.

The only way result will remain null is if it is set to null in the
initial configuration.getProperty() call, and then if it bypasses the
if-clause by having (name == null). Therefore, that is the only case
where the exception is thrown.

I didn't notice any JUnit test cases for checking the behavior when
accessing a non-existing property name (although there is a case for a
null name).

So, my question is: should the get method throw an exception when
called with a non-existent property name? If so, then the get method
needs to be changed. If not, I might recommend documenting this
difference from the DynaBean interface in some way, and perhaps
changing the above code to remove the superfluous if-test. I'd be
happy to assist if needed.

--
Bill Vollers

---------------------------------------------------------------------
To unsubscribe, e-mail: commons-dev-unsubscribe@jakarta.apache.org
For additional commands, e-mail: commons-dev-help@jakarta.apache.org