try/catch/FINALLY

On Wed, 2003-08-06 at 09:14, Marcus Börger wrote:

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Well, consider: function foo() { try { // ... } catch (Exception $e) { // ...handle it... return false; } finally { // ...clean up... } // ...continue doing whatever... return true; } The cleanup code is always to be executed, the method should of course not continue in case an exception was caught. OK, I could write: function foo() { try { // ... } catch (Exception $e) { // ...handle it... } // ...clean up ... if ($e) return false; // ...continue doing whatever... return true; } so all it boils down to is, I guess, syntactic sugar. Evil programming language sourcecode below:) ---------------------------------------------------------------------------- thekid@thekid:~ > cat FinallyTest.java class FinallyTest { public static void main(String[] args) { boolean success= FinallyTest.test(args.length > 0); System.out.println("Success? " + success); } public static boolean test(boolean dothrow) { try { if (dothrow) { throw new Exception("Test"); } } catch (Exception e) { e.printStackTrace(); return false; } finally { System.out.println("<<< In finally >>>"); } System.out.println("OK"); return true; } } thekid@thekid:~ > CLASSPATH="." java FinallyTest <<< In finally >>> OK Success? true thekid@thekid:~ > CLASSPATH="." java FinallyTest 1 java.lang.Exception: Test at FinallyTest.test(FinallyTest.java:10) at FinallyTest.main(FinallyTest.java:3) <<< In finally >>> Success? false - Timm

Hello Marcus, Wednesday, August 6, 2003, 1:14:10 PM, you wrote: CD>> What about finally ? MB> There's absolute no need for finally: MB> try { MB> } MB> catch (...) { MB> } MB> // here's you're finally code try { $this->allocateSomeResources(); throw new SomeException(); } catch( AnotherException $e ) { } finally { $this->freeSomeResource(); } This code will call freeSomeResource() -- that's why one may want to have finally. But I agree that there's no need for finally. If uncaught exception is thrown -- it's bad application design or malicious component( you cannot declare throws in function definition so some evil component can do something like " throw new ExceptionThatNobodyHandles(); // har-har-har!" . You need to refactor in first case and can do nothing in second -- if you'll start to free resources in finally after each try-catch or always catch Exception, your code will become garbage soon IMHO.

The most important thing missing from this is that you cannot rethrow the exception from the point where you suggest to place the finally code :-) --Wez.

On Wednesday, August 6, 2003, at 03:14 AM, Marcus Börger wrote:

PHP doesn't necessarily control every resources you might want to deallocate. mysql_query('LOCK ...'); try { ... do stuff } finally { mysql_query('UNLOCK...'); } .. do more stuff