Exception Handling In BPEL By using Catch Blocks or Fault Policies Or Both

I have a confusion regarding
Exception handling :
When Should i go for 1)Catch Block (Remote , or binding ) in bpel for exception handling .
2)Fault Policy , Fault binding.xml
Currently iam using catch blocks , but even fault policy is good , but can i use both...
Currently in My bpel ,when any error occurs i have to send a error notification by Email .
Currently i have exposed the email service which shuts emails and write a file with errored Message.
Hence if any error i will catch i in a parent BPEL, i will just invoke the above email, service .
So anybody can help me by giving the suggestion how to go for the best approach
Edited by: anantwag on Mar 23, 2011 6:31 AM

Currently in My bpel ,when any error occurs i have to send a error notification by Email .
Currently i have exposed the email service which shuts emails and write a file with errored Message.Seeing your use case I will suggest you to use fault handling framework (fault policy). Fault handling framework should be used where you need generic error handling framework which handles all the faults occured in any composite component. Generally BPEL catch block should be used to propagate error info/fault back to the client/to fault handling framework or to consume an error
Regards,
Anuj

Similar Messages

Fault Handling in BPEL - Continue after Catch Block

Hi,
I have a catch block in my BPEL process.
On exception, the catch block catches the error and terminates the BPEL Process.
Is it possible to loop back the flow after the catch sequence?
Thanks,
Venkat

Hi,
Thanks for your reply
Sorry, I was not clear with my question.
I have a infinite loop in my process. Inside the loop I have an invoke operation(Invokes another BPEL process) and a wait operation. If any exception occurs, my BPEL process terminates. However, I wanted my BPEL process to just continue in the loop.
I solved the issue with the help of this How to handle fault when BPEL process is polling a FTP server which is down
i.e, using the Scope activity. Place my invoke operation inside a scope and put a catchAll block only for that scope. Its working fine
Thanks,
Venkat

Best Practice for Implementing Exception Handling in BPEL

Hi All,
what is the best practice and the approach to follow Exception Handling in BPEL.
1) Do we need to implement Exception Handling in BPEL as we do in Java, means
     method 3 throws error to method 2 (if any) and
     method 2 throws error to method 1 (if any) and
     finally method 1 throws error to the main Class.
If we replicate the above scenario to BPEL
In BPEL main Scope have Custom Fault, Catch ALL
     Each Invoke is surrounded by a Scope Activity with Remote Fault, Binding Fault & Custom Fault
and follow the paradigm of Java, assuming we have Inner Scopes
     [ OR ]
2) In BPEL main Scope have all exceptions defined like
     Remote Fault,
     Binding Fault,
     anyOther System Fault (selectionFailure / forcedTermination),
     Custom Fault (if required) and
     CatchALL
     and also
     each Invoke is surrounded by a Scopes Acitivity with Custom Fault (business fault) exception Handling
I feel 1st one may not be a good practice, may be i am wrong...
Any Suggestions from experts.
Thanks in Advance
anvv sharma

Hi-
In you can create different scope and use catch branch to catch binding, remote, custom faults, business faults etc. If an error happens in a scope it will not move to the next scope( eg: you have 3 scope, error occured in 2nd scope then it will not propogate to the 3rd scope. One thing to be noticed here is your transaction in the 1st scope doesnt gets commited when an error happens in 2d scope).
You can have a catch all to catch error which are not being caught at catch level. So if any error happens which is not defined in catch block then then it will be caught in catch all branch.
Edited by: 333333 on Apr 12, 2011 9:39 AM

Use catch block to do something other than handling exception?

Hello,
I have always been under the impression that the catch block should only handle the exception thrown by the try block?
But now I'm reading a class where it's more or less used as an else if. Of course this works well, but I don't like it.
What is your view of this? A little example:
FileReader fR = null;
try{
      fR = new FileReader("file1")
catch (Exception e){
     //If file1 didn't exist try if file2 exists
     try{
         fR = new FileReader("file2")
     catch (Exception ee){
}I think it should be rewritten not using this technique?

Farmor wrote:
Hello,
I have always been under the impression that the catch block should only handle the exception thrown by the try block?
But now I'm reading a class where it's more or less used as an else if. Of course this works well, but I don't like it.
What is your view of this? A little example:
FileReader fR = null;
try{
fR = new FileReader("file1")
catch (Exception e){
//If file1 didn't exist try if file2 exists
try{
fR = new FileReader("file2")
catch (Exception ee){
}I think it should be rewritten not using this technique?There's nothing really wrong with the code you posted, but I find it ugly to write additional non-error-handling code inside nested try-catches. What happens if you want to extend this logic to 3 or 4 files? If the code could be written to avoid it, as someone else showed, I'd prefer the other way.
I'd put the file names in an array, and loop over the array until I found one I could open.

Exception Handling in BPEL

Guys,
I have exposed the following class as Web-Service, using Axis.
public class ExceptionCreator {
public ExceptionCreator(){
public ReturnObject generate(boolean flag) throws CustomException{
if(flag){
throw new CustomException("This is a custom exception");
}else{
return new ReturnObject(1,"NO EXCEPTION");
where ReturnObject is a simple JavaClass with two member variables id & name and CustomException is a class extended from Exception superclass in Java.
Using axis, writing appropriate serializers in wsdd, I created a web-service out of this and imported the WSDL from Axis as a Partner Link in BPEL.
If I pass true as Input and if I specify "{http://schemas.oracle.com/bpel/extension}remoteFault as faultName in the catch, the exception does get caught. However, I am unable to access the details of the same which looks like below:
[2005/09/26 18:44:11] "{http://schemas.oracle.com/bpel/extension}remoteFault" has been thrown.
<remoteFault xmlns="http://schemas.oracle.com/bpel/extension">
<part name="code">
<code>Server.userException</code>
</part>
<part name="summary">
<summary>when invoking endpointAddress 'http://kingfisher:9080/axis/services/ExceptionCreatorSewrvice', com.misys.equationcore.tutorials.CustomException: This is a custom exception</summary>
</part>
<part name="detail">
<detail>AxisFault faultCode: {http://schemas.xmlsoap.org/soap/envelope/}Server.userException faultSubcode: faultString: com.misys.equationcore.tutorials.CustomException: This is a custom exception faultActor: faultNode: faultDetail: {http://kingfisher:9080/axis/services/ExceptionCreatorSewrvice}fault:<exceptionMessage type="soapenc:string">String CustomException Constructor</exceptionMessage> {http://xml.apache.org/axis/}hostname:kingfisher</detail>
</part>
</remoteFault>
I am trying to access the contents of this fault in a Assign activity where I want to display the actual java exception as output.
Any clues as to how I can access the same?
Thanks in advance,
~Soumen.

Currently in My bpel ,when any error occurs i have to send a error notification by Email .
Currently i have exposed the email service which shuts emails and write a file with errored Message.Seeing your use case I will suggest you to use fault handling framework (fault policy). Fault handling framework should be used where you need generic error handling framework which handles all the faults occured in any composite component. Generally BPEL catch block should be used to propagate error info/fault back to the client/to fault handling framework or to consume an error
Regards,
Anuj

Exception handling with try/catch in acrobat

Hi
I have a problem using a try/catch block in my acrobat document-script. Try to enter the following into the debugger-console:
try{nonexistentFunction();}catch(e){console.println('\nacrobat can't catch')}
and run it. The output will be:
nonexistentFunction is not defined
1:Console:Exec
acrobat can't catch
true
The whole point of a rty/catch block is for the application NOT to throw an exception, but instead execute the catch-part of the statement. However, acrobat does both: It throws an exception AND executes the catch-block.
Is there another way to suppress the exception, or to make the try/catch-block work as it's supposed to?

> Also Adobe provides for free the JS or compiled file for Acrobat Reader to support the JS console.
Where is that file located ? How to install it or where to place it ?
What is the method referred by try67 on his site where he sells a product ?
Is that the same as the compiled file you refer to ? or did he sell his solution to adobe ?
It is helpful if people can get an idea of the nature of choices available and make informed decisions, than a cloak and dagger approach.
For some jobs that we have, I have been very frustrated by a consultant who wont even give basic info for transparent billing despite all assurances for privacy, as a result we are forced to do the job ourselves.
Dying Vet

Embedded Java in BPEL and exception handling

Hello everybody,
i want to use some embedded java code in my BPEL process (bpelx:exec). This code would sometimes throw exceptions. How can i deal with these exceptions to control my BPEL process? I would like, in a sense, to do some catching of java exceptions but at the BPEL level... for example, my java code would throw an exception, that my BPEL process would "catch" and react the way i want. Is it possible to do that?
Thanks for your help!
Nicolas

you need to throw a com.oracle.bpel.client.BPELFault ..
from the code
* This class represents a standard fault that may be thrown by the server
* during run-time. A BPEL fault has defined, minimally, a QName that
* corresponds to the fault name (there are several standard faults that
* are supported, please refer to Appendix A - Standard Faults in the BPEL
* 1.1 specification for a complete list).
* <p>
* This class can only be used from within a <code>bpelx:exec</code> activity;
* the <code>throw</code> activity can be used from BPEL code.
* <p>
* Additional information (such as a fault variable) can be passed through
* as a part. Currently, internal system errors populate error codes and
* summary messages via parts.
hth clemens

Catch exceptions out of catch block

Hello,
Here in my job we was using Log4J , but since some of our logs need complex things like replication for
some databases analise log t see where we will send in and lots of emails too , so we are developing our own log framework, my question is , there is a way to caught exceptions not declared in a try catch block?
Example: IndexOutOfBound some time are not cought in a try catch block, or some files sometimes came null and throws uncauht exceptions some times, there is a way to me listen to all execptions wich was throwed to the system and have a no catch block??
Thank You
Ricardo

When an uncaught exception occurs, the JAVA runtime system determins the ThreadGroup of the current thread and calls "uncaughtException" on that ThreadGroup object. However, the java.lang.ThreadGroup object performs the printing of the stack trace, which you will normally see in such cases.
If you want to modify this behaviour, you could write your own ThreadGroup class, which extends java.lang.ThreadGroup and provides a different implementation of uncaughtException. E.g. you could write a log message to your own log file or whatever you want.
Now you must guarantee, that all threads in your system are childs of that customized ThreadGroup. I did this in my main class:
public class Application implements Runnable {
    private String[] argv;
    public static void main(String[] argv) {
        this.argv = argv; // save this for use in the run method
        ThreadGroup tg = new MyThreadGroup();
        // start a thread in the new thread group and terminate the original main thread
        new Thread(tg, this, "main").start();
    public void run() {
        // perform all other tasks here
public class MyThreadGroup extends ThreadGroup {
    public MyThreadGroup() {
        super("MyThreadGroup");
    public void uncaughtException(Thread thread, Throwable exception) {
        // ignore death of thread
        if (exception instanceof ThreadDeath)
            return;
        // ---- perform your actions here ----
}All other threads, which are created later, are also in the new thread group, because they inherit the group from their creator.

Exception handling in IDOC using workflows

exeception handling in idoc using workflows
i. what will be the trigerring event in case of idoc ?
ii.will it be BOR -- IDOC<message_type >?
thanks in advance
naval bhatt

Hi Naval Bhatt,
it depends on what you would like to do, but there is an object IDOCAPPL, more information you find Objekttyp IDOC<MSGTYP>:
http://help.sap.com/saphelp_47x200/helpdata/en/04/92725546f311d189470000e829fbbd/frameset.htm
General how it works:
Objects, Events and Tasks to be Created
http://help.sap.com/saphelp_47x200/helpdata/en/78/2176d251ce11d189570000e829fbbd/frameset.htm
This is an example how the application should implement the exception handling in IDOC by using workflows.
Events for example:
- inputErrorOccurred
- inputFinished
Regards
Tibor

Generalised Event Exception Handler

Hi all experts,
Can anybody plz tell how to create a generalised Exception Handler , so that wenever a exception is generated in the main method the Exception Event Handler shud be initialised to catch the exception for all the exceptions generated at runtime.
I want the Exception Event Handler to catch the exceptions for RFC BAPI,EJB Webservice,etc..as i am using this in my application to give general message at runtime if any exceptions is generated from the try-catch block.
Waiting for the reply.
Regards:
SK

Hi SK,
There is a general Exception that you can use for all exceptions thrown.
just add this code for any exception you want to catch.
try
// try anything
catch(Exception e)
// catch any exception
Regards,
Marshall.

Exception handling - general concepts

ok, well i skipped the chapter on exception handling :=)
Correct me if im wrong, but lets say im writing some code and im not sure how to handle some of the exceptions that might get thrown or what exceptions will get thrown for that matter. How does one go about handling every possible exception that is "required".
I guess what im trying to ask is that if a certain block of code is calling methods that throw specific exceptions, then you will need to handle those exceptions. So that means you need to be aware of, or know to go lookup the possible exceptions that those methods can throw.
Im skipping around in Beginning Java 2, from wronx press jdk 1.4 edition

This is quite a hard one to be specific on as I think most of us learned this with a bit of trial and error.
1. IO always requires the method to be thrown ie
public void writeContents() throws IOException {
// methods
2. The compiler will tell you when you need a try /catch block
3. I often code this with;-
try {
// my methods here;
catch (Exception ignore) {}
and have empty braces with a general catch all Exception on the first run
4. Then if there are problems such as the code won't work I fill in the blanks ie;-
catch (Exception e) {System.out.println(e);}
// or e.getMessage() );
// or printStackTrace();
depending on what the first message is
5. Correct the exception now that you know what it is. Really this is a form of 'divide and conquer' as you eliminate the problems as they occur through javas exception handling abilities.
6. With a bit more practice you will implement things like finally and know when to put the handler back to 'catch (Exception ignore) {}' and when to leave it in.
7. Exception handling can also be used to instruct the client in useful ways too eg;-
try {
myTextfield.setText("Enter Your Age");
myInt = parse ...(myTextfield.getText(etc ...
catch (NumberFormatException nfe) {
myTextfield.setText("Enter Number Values Only");
// or something like
catch (NullPointerException nfe) {
myTextfield.setText("Oops you forgot to enter a value");
This has been my experience anyway + I trust I have assisted

Exception handling - Common exception handling framework

Hi,
I need to come up with a common exception handling framework in an environment where ESB and ODI are being used for interfacing and ELT operations. I am of the opinion that
1. A generic exception handling framework can be built using BPEL and can be invoked from ESB. Is my understanding correct?
2. Are there any ways that we can build this framework using ESB itself? I opinion that it's not possible as there is no concept of try-catch?
3. I am not able to find any documentation wrt exception handling when ODI is used? Can some one help me with some pointers?
4, When I come up with a common exception handling framework, will I be able to invoke the same from ODI.
Thanks,
Mahesh

Thanks for the reply Allan. I haven't used BusinessWorks.
I did go through this thread before and here's my understanding.
1. ESB provides the ability of error handling (client management API) but not the exception handling i.e. I can't redirect the flow in case there is an exception in my primary flow. Am I right with my understanding?
2. Error handling ability of ESB is limited to retryable exceptions viz-a-viz asynchrounous ESB processes (e.g. database listener not up) where in the process can be retried. Am I right here?
Thanks,
Mahesh

PL/SQL 101 : Exception Handling

Frequently I see questions and issues around the use of Exception/Error Handling in PL/SQL. More often than not the issue comes from the questioners misunderstanding about how PL/SQL is constructed and executed, so I thought I'd write a small article covering the key concepts to give a clear picture of how it all hangs together. (Note: the examples are just showing examples of the exception handling structure, and should not be taken as truly valid code for ways of handling things)
Exception Handling
Contents
1. Understanding Execution Blocks (part 1)
2. Execution of the Execution Block
3. Exceptions
4. Understanding Execution Blocks (part 2)
5. How to continue exection of statements after an exception
6. User defined exceptions
7. Line number of exception
8. Exceptions within code within the exception block
1. Understanding Execution Blocks (part 1)
The first thing that one needs to understand is almost taking us back to the basics of PL/SQL... how a PL/SQL execution block is constructed.
Essentially an execution block is made of 3 sections...
+---------------------------+
|    Declaration Section    |
+---------------------------+
|    Statements Section    |
+---------------------------+
|     Exception Section     |
+---------------------------+
The Declaration section is the part defined between the PROCEDURE/FUNCTION header or the DECLARE keyword (for anonymous blocks) and the BEGIN keyword. (Optional section)
The Statements section is where your code goes and lies between the BEGIN keyword and the EXCEPTION keyword (or END keyword if there is no EXCEPTION section). (Mandatory section)
The Exception section is where any exception handling goes and lies between the EXCEPTION keyword at the END keyword. (Optional section)
Example of an anonymous block...
DECLARE
.. declarative statements go here ..
BEGIN
.. code statements go here ..
EXCEPTION
.. exception handlers go here ..
END;
Example of a procedure/function block...
[CREATE OR REPLACE] (PROCEDURE|FUNCTION) <proc or fn name> [(<parameters>)] [RETURN <datatype>] (IS|AS)
.. declarative statements go here ..
BEGIN
.. code statements go here ..
EXCEPTION
.. exception handlers go here ..
END;
(Note: The same can also be done for packages, but let's keep it simple)
2. Execution of the Execution Block
This may seem a simple concept, but it's surprising how many people have issues showing they haven't grasped it. When an Execution block is entered, the declaration section is processed, creating a scope of variables, types , cursors, etc. to be visible to the execution block and then execution enters into the Statements section. Each statment in the statements section is executed in turn and when the execution completes the last statment the execution block is exited back to whatever called it.
3. Exceptions
Exceptions generally happen during the execution of statements in the Statements section. When an exception happens the execution of statements jumps immediately into the exception section. In this section we can specify what exceptions we wish to 'capture' or 'trap' and do one of the two following things...
(Note: The exception section still has access to all the declared items in the declaration section)
3.i) Handle the exception
We do this when we recognise what the exception is (most likely it's something we expect to happen) and we have a means of dealing with it so that our application can continue on.
Example...
(without the exception handler the exception is passed back to the calling code, in this case SQL*Plus)
SQL> ed
Wrote file afiedt.buf
1 declare
2    v_name VARCHAR2(20);
3 begin
4    select ename
5    into   v_name
6    from   emp
7    where empno = &empno;
8    dbms_output.put_line(v_name);
9* end;
SQL> /
Enter value for empno: 123
old   7:   where empno = &empno;
new   7:   where empno = 123;
declare
ERROR at line 1:
ORA-01403: no data found
ORA-06512: at line 4
(with an exception handler, we capture the exception, handle it how we want to, and the calling code is happy that there is no error for it to report)
SQL> ed
Wrote file afiedt.buf
1 declare
2    v_name VARCHAR2(20);
3 begin
4    select ename
5    into   v_name
6    from   emp
7    where empno = &empno;
8    dbms_output.put_line(v_name);
9 exception
10    when no_data_found then
11      dbms_output.put_line('There is no employee with this employee number.');
12* end;
SQL> /
Enter value for empno: 123
old   7:   where empno = &empno;
new   7:   where empno = 123;
There is no employee with this employee number.
PL/SQL procedure successfully completed.
3.ii) Raise the exception
We do this when:-
a) we recognise the exception, handle it but still want to let the calling code know that it happened
b) we recognise the exception, wish to log it happened and then let the calling code deal with it
c) we don't recognise the exception and we want the calling code to deal with it
Example of b)
SQL> ed
Wrote file afiedt.buf
1 declare
2    v_name VARCHAR2(20);
3    v_empno NUMBER := &empno;
4 begin
5    select ename
6    into   v_name
7    from   emp
8    where empno = v_empno;
9    dbms_output.put_line(v_name);
10 EXCEPTION
11    WHEN no_data_found THEN
12      INSERT INTO sql_errors (txt)
13      VALUES ('Search for '||v_empno||' failed.');
14      COMMIT;
15      RAISE;
16* end;
SQL> /
Enter value for empno: 123
old   3:   v_empno NUMBER := &empno;
new   3:   v_empno NUMBER := 123;
declare
ERROR at line 1:
ORA-01403: no data found
ORA-06512: at line 15
SQL> select * from sql_errors;
TXT
Search for 123 failed.
SQL>
Example of c)
SQL> ed
Wrote file afiedt.buf
1 declare
2    v_name VARCHAR2(20);
3    v_empno NUMBER := &empno;
4 begin
5    select ename
6    into   v_name
7    from   emp
8    where empno = v_empno;
9    dbms_output.put_line(v_name);
10 EXCEPTION
11    WHEN no_data_found THEN
12      INSERT INTO sql_errors (txt)
13      VALUES ('Search for '||v_empno||' failed.');
14      COMMIT;
15      RAISE;
16    WHEN others THEN
17      RAISE;
18* end;
SQL> /
Enter value for empno: 'ABC'
old   3:   v_empno NUMBER := &empno;
new   3:   v_empno NUMBER := 'ABC';
declare
ERROR at line 1:
ORA-06502: PL/SQL: numeric or value error: character to number conversion error
ORA-06512: at line 3
SQL> select * from sql_errors;
TXT
Search for 123 failed.
SQL>
As you can see from the sql_errors log table, no log was written so the WHEN others exception was the exception that raised the error to the calling code (SQL*Plus)
4. Understanding Execution Blocks (part 2)
Ok, so now we understand the very basics of an execution block and what happens when an exception happens. Let's take it a step further...
Execution blocks are not just a single simple block in most cases. Often, during our statements section we have a need to call some reusable code and we do that by calling a procedure or function. Effectively this nests the procedure or function's code as another execution block within the current statement section so, in terms of execution, we end up with something like...
+---------------------------------+
|    Declaration Section          |
+---------------------------------+
|    Statements Section          |
|            .                    |
| +---------------------------+ |
| |    Declaration Section    | |
| +---------------------------+ |
| |    Statements Section    | |
| +---------------------------+ |
| |     Exception Section     | |
| +---------------------------+ |
|            .                    |
+---------------------------------+
|     Exception Section           |
+---------------------------------+
Example... (Note: log_trace just writes some text to a table for tracing)
SQL> create or replace procedure a as
2    v_dummy NUMBER := log_trace('Procedure A''s Declaration Section');
3 begin
4    v_dummy := log_trace('Procedure A''s Statement Section');
5    v_dummy := 1/0; -- cause an exception
6 exception
7    when others then
8      v_dummy := log_trace('Procedure A''s Exception Section');
9      raise;
10 end;
11 /
Procedure created.
SQL> create or replace procedure b as
2    v_dummy NUMBER := log_trace('Procedure B''s Declaration Section');
3 begin
4    v_dummy := log_trace('Procedure B''s Statement Section');
5    a; -- HERE the execution passes to the declare/statement/exception sections of A
6 exception
7    when others then
8      v_dummy := log_trace('Procedure B''s Exception Section');
9      raise;
10 end;
11 /
Procedure created.
SQL> exec b;
BEGIN b; END;
ERROR at line 1:
ORA-01476: divisor is equal to zero
ORA-06512: at "SCOTT.B", line 9
ORA-06512: at line 1
SQL> select * from code_trace;
TXT
Procedure B's Declaration Section
Procedure B's Statement Section
Procedure A's Declaration Section
Procedure A's Statement Section
Procedure A's Exception Section
Procedure B's Exception Section
6 rows selected.
SQL>
Likewise, execution blocks can be nested deeper and deeper.
5. How to continue exection of statements after an exception
One of the common questions asked is how to return execution to the statement after the one that created the exception and continue on.
Well, firstly, you can only do this for statements you expect to raise an exception, such as when you want to check if there is no data found in a query.
If you consider what's been shown above you could put any statement you expect to cause an exception inside it's own procedure or function with it's own exception section to handle the exception without raising it back to the calling code. However, the nature of procedures and functions is really to provide a means of re-using code, so if it's a statement you only use once it seems a little silly to go creating individual procedures for these.
Instead, you nest execution blocks directly, to give the same result as shown in the diagram at the start of part 4 of this article.
SQL> ed
Wrote file afiedt.buf
1 create or replace procedure b (p_empno IN VARCHAR2) as
2    v_dummy NUMBER := log_trace('Procedure B''s Declaration Section');
3 begin
4    v_dummy := log_trace('Procedure B''s Statement Section');
5    -- Here we start another execution block nested in the first one...
6    declare
7      v_dummy NUMBER := log_trace('Nested Block Declaration Section');
8    begin
9      v_dummy := log_trace('Nested Block Statement Section');
10      select empno
11        into   v_dummy
12        from   emp
13       where empno = p_empno; -- Note: the parameters and variables from
                                     parent execution block are available to use!
14    exception
15      when no_data_found then
16        -- This is an exception we can handle so we don't raise it
17        v_dummy := log_trace('No employee was found');
18        v_dummy := log_trace('Nested Block Exception Section - Exception Handled');
19      when others then
20        -- Other exceptions we can't handle so we raise them
21        v_dummy := log_trace('Nested Block Exception Section - Exception Raised');
22        raise;
23    end;
24    -- ...Here endeth the nested execution block
25    -- As the nested block handled it's exception we come back to here...
26    v_dummy := log_trace('Procedure B''s Statement Section Continued');
27 exception
28    when others then
29      -- We'll only get to here if an unhandled exception was raised
30      -- either in the nested block or in procedure b's statement section
31      v_dummy := log_trace('Procedure B''s Exception Section');
32      raise;
33* end;
SQL> /
Procedure created.
SQL> exec b(123);
PL/SQL procedure successfully completed.
SQL> select * from code_trace;
TXT
Procedure B's Declaration Section
Procedure B's Statement Section
Nested Block Declaration Section
Nested Block Statement Section
No employee was found
Nested Block Exception Section - Exception Handled
Procedure B's Statement Section Continued
7 rows selected.
SQL> truncate table code_trace;
Table truncated.
SQL> exec b('ABC');
BEGIN b('ABC'); END;
ERROR at line 1:
ORA-01722: invalid number
ORA-06512: at "SCOTT.B", line 32
ORA-06512: at line 1
SQL> select * from code_trace;
TXT
Procedure B's Declaration Section
Procedure B's Statement Section
Nested Block Declaration Section
Nested Block Statement Section
Nested Block Exception Section - Exception Raised
Procedure B's Exception Section
6 rows selected.
SQL>
You can see from this that, very simply, the code that we expected may have an exception was able to either handle the exception and return to the outer execution block to continue execution, or if an unexpected exception occurred then it was able to be raised up to the outer exception section.
6. User defined exceptions
There are three sorts of 'User Defined' exceptions. There are logical situations (e.g. business logic) where, for example, certain criteria are not met to complete a task, and there are existing Oracle errors that you wish to give a name to in order to capture them in the exception section. The third is raising your own exception messages with our own exception numbers. Let's look at the first one...
Let's say I have tables which detail stock availablility and reorder levels...
SQL> select * from reorder_level;
   ITEM_ID STOCK_LEVEL
         1          20
         2          20
         3          10
         4           2
         5           2
SQL> select * from stock;
   ITEM_ID ITEM_DESC STOCK_LEVEL
         1 Pencils             10
         2 Pens                 2
         3 Notepads            25
         4 Stapler              5
         5 Hole Punch           3
SQL>
Now, our Business has told the administrative clerk to check stock levels and re-order anything that is below the re-order level, but not to hold stock of more than 4 times the re-order level for any particular item. As an IT department we've been asked to put together an application that will automatically produce the re-order documents upon the clerks request and, because our company is so tight-ar*ed about money, they don't want to waste any paper with incorrect printouts so we have to ensure the clerk can't order things they shouldn't.
SQL> ed
Wrote file afiedt.buf
1 create or replace procedure re_order(p_item_id NUMBER, p_quantity NUMBER) is
2    cursor cur_stock_reorder is
3      select s.stock_level
4            ,r.stock_level as reorder_level
5            ,(r.stock_level*4) as reorder_limit
6      from stock s join reorder_level r on (s.item_id = r.item_id)
7      where s.item_id = p_item_id;
8    --
9    v_stock cur_stock_reorder%ROWTYPE;
10 begin
11    OPEN cur_stock_reorder;
12    FETCH cur_stock_reorder INTO v_stock;
13    IF cur_stock_reorder%NOTFOUND THEN
14      RAISE no_data_found;
15    END IF;
16    CLOSE cur_stock_reorder;
17    --
18    IF v_stock.stock_level >= v_stock.reorder_level THEN
19      -- Stock is not low enough to warrant an order
20      DBMS_OUTPUT.PUT_LINE('Stock has not reached re-order level yet!');
21    ELSE
22      IF v_stock.stock_level + p_quantity > v_stock.reorder_limit THEN
23        -- Required amount is over-ordering
24        DBMS_OUTPUT.PUT_LINE('Quantity specified is too much. Max for this item: '
                                 ||to_char(v_stock.reorder_limit-v_stock.stock_level));
25      ELSE
26        DBMS_OUTPUT.PUT_LINE('Order OK. Printing Order...');
27        -- Here goes our code to print the order
28      END IF;
29    END IF;
30    --
31 exception
32    WHEN no_data_found THEN
33      CLOSE cur_stock_reorder;
34      DBMS_OUTPUT.PUT_LINE('Invalid Item ID.');
35* end;
SQL> /
Procedure created.
SQL> exec re_order(10,100);
Invalid Item ID.
PL/SQL procedure successfully completed.
SQL> exec re_order(3,40);
Stock has not reached re-order level yet!
PL/SQL procedure successfully completed.
SQL> exec re_order(1,100);
Quantity specified is too much. Max for this item: 70
PL/SQL procedure successfully completed.
SQL> exec re_order(2,50);
Order OK. Printing Order...
PL/SQL procedure successfully completed.
SQL>
Ok, so that code works, but it's a bit messy with all those nested IF statements. Is there a cleaner way perhaps? Wouldn't it be nice if we could set up our own exceptions...
SQL> ed
Wrote file afiedt.buf
1 create or replace procedure re_order(p_item_id NUMBER, p_quantity NUMBER) is
2    cursor cur_stock_reorder is
3      select s.stock_level
4            ,r.stock_level as reorder_level
5            ,(r.stock_level*4) as reorder_limit
6      from stock s join reorder_level r on (s.item_id = r.item_id)
7      where s.item_id = p_item_id;
8    --
9    v_stock cur_stock_reorder%ROWTYPE;
10    --
11    -- Let's declare our own exceptions for business logic...
12    exc_not_warranted EXCEPTION;
13    exc_too_much      EXCEPTION;
14 begin
15    OPEN cur_stock_reorder;
16    FETCH cur_stock_reorder INTO v_stock;
17    IF cur_stock_reorder%NOTFOUND THEN
18      RAISE no_data_found;
19    END IF;
20    CLOSE cur_stock_reorder;
21    --
22    IF v_stock.stock_level >= v_stock.reorder_level THEN
23      -- Stock is not low enough to warrant an order
24      RAISE exc_not_warranted;
25    END IF;
26    --
27    IF v_stock.stock_level + p_quantity > v_stock.reorder_limit THEN
28      -- Required amount is over-ordering
29      RAISE exc_too_much;
30    END IF;
31    --
32    DBMS_OUTPUT.PUT_LINE('Order OK. Printing Order...');
33    -- Here goes our code to print the order
34    --
35 exception
36    WHEN no_data_found THEN
37      CLOSE cur_stock_reorder;
38      DBMS_OUTPUT.PUT_LINE('Invalid Item ID.');
39    WHEN exc_not_warranted THEN
40      DBMS_OUTPUT.PUT_LINE('Stock has not reached re-order level yet!');
41    WHEN exc_too_much THEN
42      DBMS_OUTPUT.PUT_LINE('Quantity specified is too much. Max for this item: '
                              ||to_char(v_stock.reorder_limit-v_stock.stock_level));
43* end;
SQL> /
Procedure created.
SQL> exec re_order(10,100);
Invalid Item ID.
PL/SQL procedure successfully completed.
SQL> exec re_order(3,40);
Stock has not reached re-order level yet!
PL/SQL procedure successfully completed.
SQL> exec re_order(1,100);
Quantity specified is too much. Max for this item: 70
PL/SQL procedure successfully completed.
SQL> exec re_order(2,50);
Order OK. Printing Order...
PL/SQL procedure successfully completed.
SQL>
That's better. And now we don't have to use all those nested IF statements and worry about it accidently getting to code that will print the order out as, once one of our user defined exceptions is raised, execution goes from the Statements section into the Exception section and all handling of errors is done in one place.
Now for the second sort of user defined exception...
A new requirement has come in from the Finance department who want to have details shown on the order that show a re-order 'indicator' based on the formula ((maximum allowed stock - current stock)/re-order quantity), so this needs calculating and passing to the report...
SQL> ed
Wrote file afiedt.buf
1 create or replace procedure re_order(p_item_id NUMBER, p_quantity NUMBER) is
2    cursor cur_stock_reorder is
3      select s.stock_level
4            ,r.stock_level as reorder_level
5            ,(r.stock_level*4) as reorder_limit
6            ,(((r.stock_level*4)-s.stock_level)/p_quantity) as finance_factor
7      from stock s join reorder_level r on (s.item_id = r.item_id)
8      where s.item_id = p_item_id;
9    --
10    v_stock cur_stock_reorder%ROWTYPE;
11    --
12    -- Let's declare our own exceptions for business logic...
13    exc_not_warranted EXCEPTION;
14    exc_too_much      EXCEPTION;
15 begin
16    OPEN cur_stock_reorder;
17    FETCH cur_stock_reorder INTO v_stock;
18    IF cur_stock_reorder%NOTFOUND THEN
19      RAISE no_data_found;
20    END IF;
21    CLOSE cur_stock_reorder;
22    --
23    IF v_stock.stock_level >= v_stock.reorder_level THEN
24      -- Stock is not low enough to warrant an order
25      RAISE exc_not_warranted;
26    END IF;
27    --
28    IF v_stock.stock_level + p_quantity > v_stock.reorder_limit THEN
29      -- Required amount is over-ordering
30      RAISE exc_too_much;
31    END IF;
32    --
33    DBMS_OUTPUT.PUT_LINE('Order OK. Printing Order...');
34    -- Here goes our code to print the order, passing the finance_factor
35    --
36 exception
37    WHEN no_data_found THEN
38      CLOSE cur_stock_reorder;
39      DBMS_OUTPUT.PUT_LINE('Invalid Item ID.');
40    WHEN exc_not_warranted THEN
41      DBMS_OUTPUT.PUT_LINE('Stock has not reached re-order level yet!');
42    WHEN exc_too_much THEN
43      DBMS_OUTPUT.PUT_LINE('Quantity specified is too much. Max for this item: '
                              ||to_char(v_stock.reorder_limit-v_stock.stock_level));
44* end;
SQL> /
Procedure created.
SQL> exec re_order(2,40);
Order OK. Printing Order...
PL/SQL procedure successfully completed.
SQL> exec re_order(2,0);
BEGIN re_order(2,0); END;
ERROR at line 1:
ORA-01476: divisor is equal to zero
ORA-06512: at "SCOTT.RE_ORDER", line 17
ORA-06512: at line 1
SQL>
Hmm, there's a problem if the person specifies a re-order quantity of zero. It raises an unhandled exception.
Well, we could put a condition/check into our code to make sure the parameter is not zero, but again we would be wrapping our code in an IF statement and not dealing with the exception in the exception handler.
We could do as we did before and just include a simple IF statement to check the value and raise our own user defined exception but, in this instance the error is standard Oracle error (ORA-01476) so we should be able to capture it inside the exception handler anyway... however...
EXCEPTION
WHEN ORA-01476 THEN
... is not valid. What we need is to give this Oracle error a name.
This is done by declaring a user defined exception as we did before and then associating that name with the error number using the PRAGMA EXCEPTION_INIT statement in the declaration section.
SQL> ed
Wrote file afiedt.buf
1 create or replace procedure re_order(p_item_id NUMBER, p_quantity NUMBER) is
2    cursor cur_stock_reorder is
3      select s.stock_level
4            ,r.stock_level as reorder_level
5            ,(r.stock_level*4) as reorder_limit
6            ,(((r.stock_level*4)-s.stock_level)/p_quantity) as finance_factor
7      from stock s join reorder_level r on (s.item_id = r.item_id)
8      where s.item_id = p_item_id;
9    --
10    v_stock cur_stock_reorder%ROWTYPE;
11    --
12    -- Let's declare our own exceptions for business logic...
13    exc_not_warranted EXCEPTION;
14    exc_too_much      EXCEPTION;
15    --
16    exc_zero_quantity EXCEPTION;
17    PRAGMA EXCEPTION_INIT(exc_zero_quantity, -1476);
18 begin
19    OPEN cur_stock_reorder;
20    FETCH cur_stock_reorder INTO v_stock;
21    IF cur_stock_reorder%NOTFOUND THEN
22      RAISE no_data_found;
23    END IF;
24    CLOSE cur_stock_reorder;
25    --
26    IF v_stock.stock_level >= v_stock.reorder_level THEN
27      -- Stock is not low enough to warrant an order
28      RAISE exc_not_warranted;
29    END IF;
30    --
31    IF v_stock.stock_level + p_quantity > v_stock.reorder_limit THEN
32      -- Required amount is over-ordering
33      RAISE exc_too_much;
34    END IF;
35    --
36    DBMS_OUTPUT.PUT_LINE('Order OK. Printing Order...');
37    -- Here goes our code to print the order, passing the finance_factor
38    --
39 exception
40    WHEN exc_zero_quantity THEN
41      DBMS_OUTPUT.PUT_LINE('Quantity of 0 (zero) is invalid.');
42    WHEN no_data_found THEN
43      CLOSE cur_stock_reorder;
44      DBMS_OUTPUT.PUT_LINE('Invalid Item ID.');
45    WHEN exc_not_warranted THEN
46      DBMS_OUTPUT.PUT_LINE('Stock has not reached re-order level yet!');
47    WHEN exc_too_much THEN
48      DBMS_OUTPUT.PUT_LINE('Quantity specified is too much. Max for this item: '
                              ||to_char(v_stock.reorder_limit-v_stock.stock_level));
49* end;
SQL> /
Procedure created.
SQL> exec re_order(2,0);
Quantity of 0 (zero) is invalid.
PL/SQL procedure successfully completed.
SQL>
Lastly, let's look at raising our own exceptions with our own exception numbers...
SQL> ed
Wrote file afiedt.buf
1 create or replace procedure re_order(p_item_id NUMBER, p_quantity NUMBER) is
2    cursor cur_stock_reorder is
3      select s.stock_level
4            ,r.stock_level as reorder_level
5            ,(r.stock_level*4) as reorder_limit
6            ,(((r.stock_level*4)-s.stock_level)/p_quantity) as finance_factor
7      from stock s join reorder_level r on (s.item_id = r.item_id)
8      where s.item_id = p_item_id;
9    --
10    v_stock cur_stock_reorder%ROWTYPE;
11    --
12    exc_zero_quantity EXCEPTION;
13    PRAGMA EXCEPTION_INIT(exc_zero_quantity, -1476);
14 begin
15    OPEN cur_stock_reorder;
16    FETCH cur_stock_reorder INTO v_stock;
17    IF cur_stock_reorder%NOTFOUND THEN
18      RAISE no_data_found;
19    END IF;
20    CLOSE cur_stock_reorder;
21    --
22    IF v_stock.stock_level >= v_stock.reorder_level THEN
23      -- Stock is not low enough to warrant an order
24      [b]RAISE_APPLICATION_ERROR(-20000, 'Stock has not reached re-order level yet!');[/b]
25    END IF;
26    --
27    IF v_stock.stock_level + p_quantity > v_stock.reorder_limit THEN
28      -- Required amount is over-ordering
29

its nice article, have put up this one the blog
site,Nah, I don't have time to blog, but if one of the other Ace's/Experts wants to copy it to a blog with reference back to here (and all due credit given ;)) then that's fine by me.
I'd go for a book like "Selected articles by OTN members" or something. Does anybody have a list of links of all those mentioned articles?Just these ones I've bookmarked...
Introduction to regular expressions ... by CD
When your query takes too long ... by Rob van Wijk
How to pipeline a function with a dynamic number of columns? by ascheffer
PL/SQL 101 : Exception Handling by BluShadow

Exception Handling Standards -The exception Exception should never been thrown. Always Subclass Exception and throw the subclassed Classes.

In the current project my exception handling implementation is as follows :
Exception Handling Layer wise :
DL layer :
catch (Exception ex)
bool rethrow = ExceptionPolicy.HandleException(ex, "Ui Policy");
if (rethrow)
throw;
BL Layer
catch (Exception ex)
bool rethrow = ExceptionPolicy.HandleException(ex, "Ui Policy");
if (rethrow)
throw;
UI Layer
catch (Exception ex)
bool rethrow = ExceptionPolicy.HandleException(ex, "Ui Policy");
if (rethrow)
Response.Redirect("ErrorPage.aspx", false);
We have a tool to check the standards. And tool output is as follows :
The exception Exception should never been thrown. Always Subclass Exception and throw the subclassed Classes.
I need suggestions on how to implement the same according to standards.

Your tool is wrong if it says to never throw Exception. This was a common recommendation back in the .NET v1 days but has long since been thrown out. It is perfectly fine to use Exception when you have a general exception that provides no information
that an application can use to make an informed opinion.
The general rules of exception throwing is to throw the most specific exception that makes sense. If there is no specific exception that applies and it would be useful for the caller to handle the exception differently than other exceptions then creating
a custom exception type is warranted. Otherwise throwing Exception is reasonable. As an example you might have an application that pulls back product data given an ID. There is no built in exception that says the ID is invalid. However an invalid ID
is something that an application may want to handle differently than, say, an exception about the product being discontinued. Therefore it might make sense to create an ItemNotFoundException exception that the application can react to.
Conversely there is no benefit in having different exception types for disk full and disk quota met. The application will respond the same in either case.
Michael Taylor
http://blogs.msmvps.com/p3net

Exception handling in ODI - common exception handling framework

Hi,
I need to come up with a common exception handling framework in an environment where ESB and ODI are being used for interfacing and ELT operations. I am of the opinion that
1. I am not able to find any documentation wrt exception handling when ODI is used? Can some one help me with some pointers?
2, When I come up with a common exception handling framework using BPEL, will I be able to invoke the same from ODI.
Thanks,
Mahesh

Thanks for the reply Allan. I haven't used BusinessWorks.
I did go through this thread before and here's my understanding.
1. ESB provides the ability of error handling (client management API) but not the exception handling i.e. I can't redirect the flow in case there is an exception in my primary flow. Am I right with my understanding?
2. Error handling ability of ESB is limited to retryable exceptions viz-a-viz asynchrounous ESB processes (e.g. database listener not up) where in the process can be retried. Am I right here?
Thanks,
Mahesh

Exception Handling In BPEL By using Catch Blocks or Fault Policies Or Both

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