Request for howto - error processing best practise

Question

Hi JDev Team. Something I would like to see in a future HOWTO would be error handling in a BC4J/JSP application. What is best practise? How do we make sure that when a database error occurs, we can trap the error and provide a friendly error message, or failing that, at least ensure the standard error is usable by a maintenance programmer. For eg. the following error occurs if a referential constraint restricts the delete:
javax.servlet.jsp.JspException: JBO-26041: Failed to post data to database during "Delete": SQL Statement " DELETE FROM TECHTRANSFER.TTSITES Sites WHERE SITEID=:1".
in fact the same error message is displayed for almost any database error - the programmer can't fix the problem when he has no idea what it is!! (same with update and insert)
I wasn't going to request this until I had read all of the help available on error processing but the way this project is going I won't get time. If you think that it is adequately covered in the help, then fine, just let me know where.
Thanks,
Simon

Answer 1

You can enclose your bc4j/jsp code with a try / catch expression. That way if a failure occurs, you can trap it, display a friendy error, and do whatever you want with the exception.
What I have been doing for develpment purposes, is send via email a modified errorpage.jsp. Here is what gets emailed to me (*'s in potentially sensitive data) and displayed to the screen (I'm eventually going to replace all the displayed garbage with something friendly):
An error occured in application PDC User Administration
User Session Properties:
Sesion ID: *********
App ID: *********
User Name: *********
User ID: *********
Priv Role: *********
Password: *********
Org No: *********
First Name: skunitzer
Last Name: ANALYST
App Title : PDC User Administration
Current Url: insertNewUser.jsp
Specific error is javax.servlet.jsp.JspException: JBO-25013: Too many objects match the primary key oracle.jbo.Key[1423 ].
Parameters:
LastName
Kunitzer
EmailAddress
[email protected]
FirstName
SteveLiveTest
OrgNo
PhoneWorkNo
I have no phone #
ExpireDate
2001-04-26
ExpireDateString
jRQiIsFGANIbrGlihGTl[epofZmSNgEkGqbHN@iErHNPRi
UserID
UserPrivs
Exception:
javax.servlet.jsp.JspException: JBO-25013: Too many objects match the primary key oracle.jbo.Key[1423 ].
Message:
JBO-25013: Too many objects match the primary key oracle.jbo.Key[1423 ].
Localized Message:
JBO-25013: Too many objects match the primary key oracle.jbo.Key[1423 ].
Stack Trace:
javax.servlet.jsp.JspException: JBO-25013: Too many objects match the primary key oracle.jbo.Key[1423 ].
at java.lang.Throwable.fillInStackTrace(Native Method)
at java.lang.Throwable.fillInStackTrace(Compiled Code)
at java.lang.Throwable.<init>(Compiled Code)
at java.lang.Exception.<init>(Compiled Code)
...Stack Trace goes on but I won't bother with it anymore...
While not always as specific as I would like, I have not had too much trouble hunting down the errors.
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