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| topmahajan |
 Posted: Thu Mar 02, 2017 2:30 pm Post subject: Catching Java Exception in Esql |
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Newbie
Joined: 18 Dec 2012
Posts: 7
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Hi,
All I am trying to find out if below scenario is possible (I am using IIB 9.0.0.2 version):
1. I am calling a Java Function from esql code
2. If I throw a user exception in Java Function (MbUserException), is it possible to pass this exception back to esql code so that it is treated as exception in esql code ?
Note: Currently we are passing all the exception details from java function in the Environment . (Reference to Environment is passed as a argument while calling Java function from esql). So, I do have the exception details in esql but then I need to check environment and act accordingly. |
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| fjb_saper |
| Posted: Thu Mar 02, 2017 3:24 pm Post subject: Re: Catching Java Exception in Esql |
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Grand High Poobah
Joined: 18 Nov 2003
Posts: 20729
Location: LI,NY
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| topmahajan wrote: |
Hi,
All I am trying to find out if below scenario is possible (I am using IIB 9.0.0.2 version):
1. I am calling a Java Function from esql code
2. If I throw a user exception in Java Function (MbUserException), is it possible to pass this exception back to esql code so that it is treated as exception in esql code ?
Note: Currently we are passing all the exception details from java function in the Environment . (Reference to Environment is passed as a argument while calling Java function from esql). So, I do have the exception details in esql but then I need to check environment and act accordingly. |
If I remember correctly, you're not allowed an exception for a Java method being called from ESQL... 
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| topmahajan |
| Posted: Sun Mar 05, 2017 2:42 pm Post subject: Re: Catching Java Exception in Esql |
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Newbie
Joined: 18 Dec 2012
Posts: 7
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| fjb_saper wrote: |
If I remember correctly, you're not allowed an exception for a Java method being called from ESQL... |
Thanks for reply. I am not able to find any details about this scenario anywhere. So, was not sure and thought to ask in the forum. |
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| mqjeff |
| Posted: Mon Mar 06, 2017 6:29 am Post subject: |
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Grand Master
Joined: 25 Jun 2008
Posts: 17447
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You should be able to catch this exception using the ESQL normal try/catch (which isn't named try/catch).
You might have to convert your Java Exception into an MBUserException in your java code.
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| topmahajan |
| Posted: Mon Mar 06, 2017 6:48 pm Post subject: |
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Newbie
Joined: 18 Dec 2012
Posts: 7
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Sorry, didn't get you exactly what do u mean by using the ESQL normal try/catch (which isn't named try/catch).
Regarding Java Exception, yes I am converting the Java exception to MBUserException. But not able to find, if I throw MBUserExcption in Java function, how I will catch it in ESQL from where I am calling the Java function? |
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| mqjeff |
| Posted: Tue Mar 07, 2017 5:04 am Post subject: |
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Grand Master
Joined: 25 Jun 2008
Posts: 17447
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| topmahajan wrote: |
| Sorry, didn't get you exactly what do u mean by using the ESQL normal try/catch (which isn't named try/catch). |
I mean that ESQL has a try/catch structure, where you can wrap a set of one or more statements in a block, and if one of those statements throws an exception, you can catch it and process it.
But ESQL doesn't call the block of statements that you wan;t to try with the word "Try", and it doesn't call the exception handling block "catch".
Please refer to the Knowledge Center for more information on how ESQL handles this.
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| topmahajan |
| Posted: Thu Mar 09, 2017 4:01 pm Post subject: |
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Newbie
Joined: 18 Dec 2012
Posts: 7
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Thanks for the reply, I think you are referring to use Handlers in esql, which we can use for catching the exceptions in esql.
But while trying to implement to throw the exception back from Java to esql, I found that we can't throw the exception back from the Java function because I had to add throws MbUserException statement in Java function definition like: public static String getValue(String s1) throws MbUserException.
And this is not allowed and IIB throws below exception if we do this:
File:CHARACTER:F:\build\slot1\S900_P\src\DataFlowEngine\ImbRdl\ImbRdlExternalJava.cpp
Line:INTEGER:1138
Function:CHARACTER:ESQL2JavaMethodResolver::decodeReturnStatus
Type:CHARACTER:
Name:CHARACTER:
Label:CHARACTER:
Catalog:CHARACTER:BIPmsgs
Severity:INTEGER:3
Number:INTEGER:2927
Text:CHARACTER:The Java method has a throws clause
So, I don't think that this scenario can be implemented. |
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| mqjeff |
| Posted: Fri Mar 10, 2017 4:58 am Post subject: |
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Grand Master
Joined: 25 Jun 2008
Posts: 17447
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https://www.ibm.com/support/knowledgecenter/en/SSMKHH_9.0.0/com.ibm.etools.mft.doc/ac30495_.htm
So change your java throws clause to MbException, not MbUserException.
https://www.ibm.com/support/knowledgecenter/SSMKHH_9.0.0/com.ibm.etools.mft.doc/ak20700_.htm
So wrap your Java procedure call in a handler block.
If the selected exception is a user exception (that is, it originated in a THROW statement), the SQL code, state, native error, and error text are taken from the first four inserts of the exception, in order. The resulting state value is taken as is (not prefixed by a letter such as "U"). The letter "U" is not used by the broker as an origin indicator. If you want to define a unique SQL state rather than to imitate an existing one, use SQL states starting with the letter "U". If you use SQL states that start with the letter "U", you can write an error handler to match all user-defined and thrown exceptions with a LIKE'U%' operator.
So declare your handler to catch the SQLSTATE that you populate in your MBUserException, per the above rules.
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| mgk |
| Posted: Sat Mar 11, 2017 2:21 am Post subject: |
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Padawan
Joined: 31 Jul 2003
Posts: 1639
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The above will not work for ESQL calling Java as currently no Java exceptions can be thrown back from Java to ESQL. This scenario would work for ESQL calling .NET where exceptions are automatically turned back into IIB Exceptions and can therefore be caught in ESQL Handlers. If you need this functionality for ESQL calling Java, you should raise a requirement. In the meantime, you can put an extra String "Out" parameter on your function, catch the exception on the Java side and return a "toString()" of the exception in the additional parameter.
Kind regards.
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The postings I make on this site are my own and don't necessarily represent IBM's positions, strategies or opinions. |
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