On Sun, Oct 27, 2013 at 1:51 AM, Damjan Jovanovic <damjan....@gmail.com>wrote:
> an > > On Fri, Oct 25, 2013 at 5:24 PM, Jörg Schaible <joerg.schai...@gmx.de> > wrote: > > Hi Damjan, > > > > Damjan Jovanovic wrote: > > > >> On Fri, Oct 25, 2013 at 12:36 PM, Jörg Schaible > >> <joerg.schai...@scalaris.com> wrote: > >>> Hi Damjan, > >>> > >>> Damjan Jovanovic wrote: > >>> > >>> [snip] > >>> > >>> Thanks for explanation. > >>> > >>>> We would be able to adapt that for Java < 1.7 by swallowing the close > >>>> exception instead of calling addSuppressed() on the primary exception, > >>>> but the show stopper is catching and rethrowing the primary exception > >>>> (Throwable), which javac < 1.7 refuses to compile because it doesn't > >>>> do "Rethrowing Exceptions with More Inclusive Type Checking" > >>>> ( > http://docs.oracle.com/javase/7/docs/technotes/guides/language/catch-multiple.html > ). > >>>> > >>>> But this would work and always sets succeeded correctly without > >>>> catch/re-throw: > >>>> > >>>> final InputStream is = factoryMethodThatCanThrow(); > >>>> boolean succeeded = false; > >>>> try { > >>>> try { > >>>> is.methodThatCanThrow(); > >>>> } finally { > >>>> } > >>>> succeeded = true; > >>>> } finally { > >>>> closeSafely(!succeeded, is); > >>>> } > >>> > >>> I guess the nested try was unintentionally ;-) > >>> > >>> Cheers, > >>> Jörg > >> > >> Well that actually won't work, because the "succeeded = true;" will be > >> skipped if there is a "return;" in the inner try. > > > > Well, but this has to be done in our code, so we can either change it or > set > > "succedded = true" before the return as well. > > > > To mimic Java 7, we could also implement: > > > > ============= %< =============== > > Throwable t = null; > > try { > > } (catch IOException e) { t = e; throw e; } > > // ... another line for each checked exception > > } (catch RuntimeException e) { t = e; throw e; } > > } (catch Error e) { t = e; throw e; } > > } finally { > > closeSafely(t != null, is); > > } > > ============= %< =============== > > > > but as commented, we have to add a catch for every checked exception, > > anotehr one for RuntimeException and one for Error. The approach with the > > succeeded flag seems easier ... > > > >> Other than a custom Java compiler, I guess there's no clean way of > >> doing this in Java < 1.7. There's really only option 2 - with being > >> careful to always set succeeded correctly on all paths out of the try > >> block. Almost like releasing memory in C. > > > > Yep. > > > > Cheers, > > Jörg > > > > One thing that amuses me to no end, is that while it's at least a > solved problem in Java 7, exceptions thrown from C#'s Dispose() method > in a using() block always swallow the original exception, just like an > uncaught close() exception in Java's finally :) > ( > http://blogs.infosupport.com/the-c-using-statement-and-suppressed-exceptions-compared-to-java-7-try-with/ > ). > > Anyway I now think the way forward is Java 7. Java 5 was EOL since 3 > November 2009, and Java 6 was EOL since February 2013 (with a last > update on 6 March 2013). There are ways of getting Java 7 features > like try-with-resources on Android > (https://github.com/yareally/Java7-on-Android) and besides Imaging's > use of java.awt.* packages is a bigger barrier there. Applications and > JVMs will eventually support Java 7 anyway, and even if they don't, a > special compiler could produce binaries for earlier versions of Java. > > Can I just go change the POM to Java 7 or do we need a vote? > I do not think you need a vote. Since the 0.x version is used in the wild, you might want to poll the user base as to their JRE requirements. For me, moving to Java 6 is fine. Java 7 is a little more adventurous, a good thing in general since no [commons] component has made Java 7 a minimum yet. Might as well test the waters. Gary > > Damjan > > --------------------------------------------------------------------- > To unsubscribe, e-mail: dev-unsubscr...@commons.apache.org > For additional commands, e-mail: dev-h...@commons.apache.org > > -- E-Mail: garydgreg...@gmail.com | ggreg...@apache.org Java Persistence with Hibernate, Second Edition<http://www.manning.com/bauer3/> JUnit in Action, Second Edition <http://www.manning.com/tahchiev/> Spring Batch in Action <http://www.manning.com/templier/> Blog: http://garygregory.wordpress.com Home: http://garygregory.com/ Tweet! http://twitter.com/GaryGregory
