Finally block to behave differently

Question

I have a condition like this

String str = null;

try{
  ...
  str = "condition2";
}catch (ApplicationException ae) {
  str = "condition3";
}catch (IllegalStateException ise) {
  str = "condition3";
}catch (Exception e) {
  str = "condition3";
}

if(str == null){
  str = "none";
}

Now I want to sum up all str = "condition3"; in one line. As finally block runs always so that will not fulfill my needs. What else can be done.

I'm not sure what benefit you're looking for... if you want the error string to be the same for all 3 exceptions, then use the below answers. If not, and there's more code in each of the exception blocks we're not seeing, then I don't see that repeating one line is all that bad. — billjamesdev, May 29 '12 at 05:27
what does it mean "all str="condition3"? if you want to sum up all str, it will be consist from cond2 and one from three exceptions. — Dmitry Zagorulkin, May 29 '12 at 05:29
@ Bill James: After all this. Only "I don't see that repeating one line is all that bad" idea will work for me. — Muhammad Imran Tariq, May 29 '12 at 05:37
Dont you think that there should be a block like catchFinally.... — Muhammad Imran Tariq, May 29 '12 at 05:52
Suppose you have a `catchFinally`, show us how it would work. — weston, May 29 '12 at 08:11
I suggest that this 'requirement' is evidence of a much bigger problem. More probably you should be letting the exception propogate, rather than assigning special values based on whether or not you got an exception. And how exactly is `str` ever going to be null? — user207421, May 29 '12 at 10:16

Asaph · Accepted Answer · 2012-05-29T05:34:20.653

6

Beginning in Java 7, you can catch multiple exception types in a single catch block. The code looks something like this:

String str = null;

try {
    ...
    str = "condition2";
} catch (ApplicationException|IllegalStateException|Exception ex) {
    str = "condition3";
}

BTW: The code you've posted, as well as my Java 7 code could all be collapsed into simply catch (Exception e), because Exception is a superclass of both ApplicationException and IllegalStateException.

edited May 29 '12 at 05:34

answered May 29 '12 at 05:22

Asaph

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3

But isn't that pointless since the first two extend `Exception`? He should just catch `Exception` as long as he's doing that anyway. – Paul Bellora May 29 '12 at 05:25
I'm guessing he's not showing all the code there, so grouping them like this probably won't work. – billjamesdev May 29 '12 at 05:25
@PaulBellora: Yes. But the same is true of the OP's equivalent Java 6 code. I'm just demonstrating the syntax. Nevertheless, I'll add a note about that. – Asaph May 29 '12 at 05:26
Catch (ApplicationException|IllegalStateException|Exception) : is that necessary to keep Exception there........ as it is super class, i mean Exception alone is sufficient – Maddy May 29 '12 at 05:29
They are subclasses but I want to print different message for each sub exception. – Muhammad Imran Tariq May 29 '12 at 05:30
2

If you want to print a different message for each exception type, you need to do the three different blocks you posted in your original question. – Louis Wasserman May 29 '12 at 05:50

score 2 · Answer 2 · answered May 29 '12 at 05:26

2

You can use Java 7 exception handling syntax. Java 7 supports multiple Exception handling in one catch block. Exp -

String str = null;

try{
  ...
  str = "condition2";
}catch (ApplicationException | IllegalStateException | Exception  ae) {
  str = "condition3";
}

answered May 29 '12 at 05:26

Pramod Kumar

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I dont want grouping exception as each exception will have a seperate message etc – Muhammad Imran Tariq May 29 '12 at 05:28
In this case you will have to follow traditional try catch block. try{ ... str = "condition2"; }catch (ApplicationException ae) { str = "condition3"; }catch (IllegalStateException ise) { str = "condition3"; }catch (Exception e) { str = "condition3"; } – Pramod Kumar May 29 '12 at 06:37

Chandra Sekhar · Answer 3 · 2012-05-29T05:52:54.470

1

try{
  ...
  str = "condition2";
}catch (Exception ae) {
 str = "condition3";
}

As all others are subclasses of Exception. If you want to show different messages, then can try as follow

try{
   ...
   str = "condition2";
}catch(ApplicationException | IllegalStateException e){
if(e instanceof ApplicationException)
    //your specfic message
    else if(e instanceof IllegalStateException)
    //your specific message
    else
        //your specific message
    str = "condition3";
}

edited May 29 '12 at 05:52

answered May 29 '12 at 05:26

Chandra Sekhar

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yes they are subclasses but I want to print different message for each sub exception. – Muhammad Imran Tariq May 29 '12 at 05:29

score 1 · Answer 4 · answered May 29 '12 at 05:34

1

You must add "final" keyword if you are using Java 7 feature of catching multiple exception in single catch block

catch (final ApplicationException|IllegalStateException|Exception ex) {

answered May 29 '12 at 05:34

Kumar Vivek Mitra

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score 0 · Answer 5 · answered May 29 '12 at 05:29

0

As you are doing same thing in ApplicationException and IllegalStateException catch blocks and in general exception Exception catch block, then you can remove ApplicationException and IllegalStateException blocks.

answered May 29 '12 at 05:29

Pokuri

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george_h · Answer 6 · 2012-05-31T14:34:34.557

0

I'm going to go out on a limb here and provide this:

String str = null;

 try{
     ...
     str = "condition2";
 }catch (Throwable e) {
    str = "condition3";
 }
 finally {
     if(str == null){
         str = "none";
     }
 }

If this is not what you mean by "sum up" then please clarify.

Please read

http://www.tutorialspoint.com/java/java_exceptions.htm http://docs.oracle.com/javase/tutorial/essential/exceptions/

edited May 31 '12 at 14:34

answered May 29 '12 at 05:31

george_h

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catchFinally will be a block that will execute only after catch statement(s). – Muhammad Imran Tariq May 31 '12 at 12:07

Finally block to behave differently

6 Answers6