Re: [wtp-dev] java.lang.NoSuchMethodError: org.eclipse.wst.common.framew

[Arthur Ryman <ryman@xxxxxxxxxx>]

Jason,

You changed the signature so the existing
class files think the original method is missing. However, you're on the
right track. The way to evolve a return type is to keep the signature but
return an object that extends the return type. Then new clients of the
API can do an instanceof check on the returned object and typecast it safely
to the extended interface. That way old clients still work and new clients
can take advantage of the new extended interface.

The code for new clients is something
like this:

IDataModelOperation operation = model.getDefaultOperation(..);

if (operation instanceof IDataModelPlausibleOperation)
{

        IDataModelPlausibleOperation
plausible = (IDataModelPlausibleOperation) operation;
        ...

}

We are "morally" obligated
to revert the signature to "unbreak" Geronimo. Any new WTP 1.5
code that uses the new signature should revert and do the typesafe typecast.


Arthur Ryman,
IBM Software Group, Rational Division

blog: http://ryman.eclipsedevelopersjournal.com/
phone: +1-905-413-3077, TL 969-3077
assistant: +1-905-413-2411, TL 969-2411
fax: +1-905-413-4920, TL 969-4920
mobile: +1-416-939-5063, text: 4169395063@xxxxxxx

Jason A Sholl <jsholl@xxxxxxxxxx>
Sent by: wtp-dev-bounces@xxxxxxxxxxx

05/15/2006 03:20 PM

Please respond to
"General discussion of project-wide or architectural issues." <wtp-dev@xxxxxxxxxxx>

To	"General discussion of project-wide or architectural issues." <wtp-dev@xxxxxxxxxxx>
cc	wtp-dev@xxxxxxxxxxx, wtp-dev-bounces@xxxxxxxxxxx
Subject	Re: [wtp-dev] java.lang.NoSuchMethodError:        org.eclipse.wst.common.frameworks.datamodel.IDataModel.getDefaultOperation()Lorg/eclipse/wst/common/frameworks/datamodel/IDataModelOperation;

I did change this back in March, but am not sure why this is broken.  The
change was to return an IDataModelPausibleOperation
instead of IDataModelOperation,
however, IDataModelPausibleOperation
extends IDataModelOperation..
 Why would that cause breakage? 

Thank you,

Jason A. Sholl
jsholl@xxxxxxxxxx
919-543-0011 (t/l 441-0011)

Arthur Ryman <ryman@xxxxxxxxxx>
Sent by: wtp-dev-bounces@xxxxxxxxxxx

05/15/2006 03:07 PM

Please respond to
"General discussion of project-wide or architectural issues." <wtp-dev@xxxxxxxxxxx>

To	wtp-dev@xxxxxxxxxxx
cc
Subject	[wtp-dev]         java.lang.NoSuchMethodError: org.eclipse.wst.common.frameworks.datamodel.IDataModel.getDefaultOperation()Lorg/eclipse/wst/common/frameworks/datamodel/IDataModelOperation;

Did someone delete a method from this interface? This was reported at Geronimo.
I opened a bug to track it [1] 

[1] https://bugs.eclipse.org/bugs/show_bug.cgi?id=141850

Arthur Ryman,
IBM Software Group, Rational Division

blog: http://ryman.eclipsedevelopersjournal.com/
phone: +1-905-413-3077, TL 969-3077
assistant: +1-905-413-2411, TL 969-2411
fax: +1-905-413-4920, TL 969-4920
mobile: +1-416-939-5063, text: 4169395063@xxxxxxx_______________________________________________
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