Posted by
Joachim Wesner on
Nov 08, 2009; 11:13pm
URL: http://imagej.273.s1.nabble.com/Return-On-Error-tp3690523p3690525.html
Hmm,
IMHO this seems not very Java-like as it also would require to augment all
calls to lower
level routines with error checking, just what one would like to avoid (Or
did I get something wrong?)
Wouldn´t it be better to use to use a user-defined exception to throw at
the intended point
of premature return and use try-catch in the run method (which
unfortunatelly also would not leave the
remaining source code totally unchanged, as one would need to declare all
intermediate routines
as "throws xxx", which however would only be required at the top of each
method, not on each call..
Just my ideas...
I hhink some time ago we already had this topic somewhere in this forum!?
Joachim
Michael Doube
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GOV> Re: Return On Error
06.11.2009 21:11
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Hi David
In a PlugIn the run() method returns void so you can just
return;
If one of the other methods that run() calls finds an error it could
return an error value to run(), which run() then uses to decide whether
or not to return, or do something else.
A common use is to call a showDialog() method in the run() method, which
shows a dialog for user input and returns false if the dialog is
cancelled. When the dialog method returns false then run() returns and
the plugin terminates.
public void run(String arg){
if (!showDialog()){
return;
}
//otherwise keep executing run()
}
If you hit OK, showDialog() returns true and the plugin continues.
Michael
David William Webster wrote:
> Is there any way to return to ImageJ from a plugin when a potential error
> is detected (e.g. if n input parameter has a bad value.) System.exit()
> kicks me all the way out of ImageJ.
>
> David Webster
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