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https://issues.apache.org/jira/browse/LUCENE-3334?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Uwe Schindler updated LUCENE-3334:
----------------------------------
Summary: IOUtils.closeSafely should log suppressed Exceptions in stack
trace of original Exception (a new feature of Java 7) (was:
IOUtils.closeSafely should use log suppressed Exceptions in stack trace of
original Exception (a new feature of Java 7))
> IOUtils.closeSafely should log suppressed Exceptions in stack trace of
> original Exception (a new feature of Java 7)
> -------------------------------------------------------------------------------------------------------------------
>
> Key: LUCENE-3334
> URL: https://issues.apache.org/jira/browse/LUCENE-3334
> Project: Lucene - Java
> Issue Type: Improvement
> Components: core/other
> Reporter: Uwe Schindler
> Assignee: Uwe Schindler
> Priority: Minor
> Attachments: LUCENE-3334.patch
>
>
> I was always against Java 6 support, as it brings no really helpful new
> features into Lucene. But there are several things that make life easier in
> coming Java 7 (hopefully on July 28th, 2011). One of those is simplier
> Exception handling and suppression on Closeable, called "Try-With-Resources"
> (see http://docs.google.com/View?id=ddv8ts74_3fs7483dp, by the way all Lucene
> classes support these semantics in Java 7 automatically, the cool try-code
> below would work e.g. for IndexWriter, TokenStreams,...).
> We already have this functionality in Lucene since adding the
> IOUtils.closeSafely() utility (which can be removed when Java 7 is the
> minimum requirement of Lucene - maybe in 10 years):
> {code:java}
> try (Closeable a = new ...; Closeable b = new ...) {
> ... use Closeables ...
> } catch (Exception e) {
> dosomething;
> throw e;
> }
> {code}
> This code will close a and b in an autogenerated finally block and supress
> any exception. This is identical to our IOUtils.closeSafely:
> {code:java}
> Exception priorException = null;
> Closeable a,b;
> try (Closeable a = new ...; Closeable b = new ...) {
> a = new ...;
> b = new ...
> ... use Closeables ...
> } catch (Exception e) {
> priorException = e;
> dosomething;
> } finally {
> IOUtils.closeSafely(priorException, a, b);
> }
> {code}
> So this means we have the same functionality without Java 7, but there is one
> thing that makes logging/debugging much nicer:
> The above Java 7 code also adds maybe suppressed Exceptions in those
> Closeables to the priorException, so when you print the stacktrace, it not
> only shows the stacktrace of the original Exception, it also prints all
> Exceptions that were suppressed to throw this Exception (all
> Closeable.close() failures):
> {noformat}
> org.apache.lucene.util.TestIOUtils$TestException: BASE-EXCEPTION
> at
> org.apache.lucene.util.TestIOUtils.testSuppressedExceptions(TestIOUtils.java:61)
> at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
> at
> sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)
> at
> sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
> at java.lang.reflect.Method.invoke(Method.java:601)
> at
> org.junit.runners.model.FrameworkMethod$1.runReflectiveCall(FrameworkMethod.java:44)
> at
> org.junit.internal.runners.model.ReflectiveCallable.run(ReflectiveCallable.java:15)
> at
> org.junit.runners.model.FrameworkMethod.invokeExplosively(FrameworkMethod.java:41)
> at
> org.junit.internal.runners.statements.InvokeMethod.evaluate(InvokeMethod.java:20)
> at org.junit.rules.TestWatchman$1.evaluate(TestWatchman.java:48)
> at
> org.junit.internal.runners.statements.RunBefores.evaluate(RunBefores.java:28)
> at
> org.junit.internal.runners.statements.RunAfters.evaluate(RunAfters.java:31)
> at
> org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:76)
> at
> org.apache.lucene.util.LuceneTestCase$LuceneTestCaseRunner.runChild(LuceneTestCase.java:1486)
> at
> org.apache.lucene.util.LuceneTestCase$LuceneTestCaseRunner.runChild(LuceneTestCase.java:1404)
> at org.junit.runners.ParentRunner$3.run(ParentRunner.java:193)
> at org.junit.runners.ParentRunner$1.schedule(ParentRunner.java:52)
> at org.junit.runners.ParentRunner.runChildren(ParentRunner.java:191)
> at org.junit.runners.ParentRunner.access$000(ParentRunner.java:42)
> at org.junit.runners.ParentRunner$2.evaluate(ParentRunner.java:184)
> at
> org.junit.internal.runners.statements.RunBefores.evaluate(RunBefores.java:28)
> at
> org.junit.internal.runners.statements.RunAfters.evaluate(RunAfters.java:31)
> at org.junit.runners.ParentRunner.run(ParentRunner.java:236)
> at junit.framework.JUnit4TestAdapter.run(JUnit4TestAdapter.java:39)
> at
> org.apache.tools.ant.taskdefs.optional.junit.JUnitTestRunner.run(JUnitTestRunner.java:420)
> at
> org.apache.tools.ant.taskdefs.optional.junit.JUnitTestRunner.launch(JUnitTestRunner.java:911)
> at
> org.apache.tools.ant.taskdefs.optional.junit.JUnitTestRunner.main(JUnitTestRunner.java:768)
> Suppressed: java.io.IOException: TEST-IO-EXCEPTION-1
> at
> org.apache.lucene.util.TestIOUtils$BrokenCloseable.close(TestIOUtils.java:36)
> at org.apache.lucene.util.IOUtils.closeSafely(IOUtils.java:58)
> at
> org.apache.lucene.util.TestIOUtils.testSuppressedExceptions(TestIOUtils.java:62)
> ... 26 more
> Suppressed: java.io.IOException: TEST-IO-EXCEPTION-2
> at
> org.apache.lucene.util.TestIOUtils$BrokenCloseable.close(TestIOUtils.java:36)
> at org.apache.lucene.util.IOUtils.closeSafely(IOUtils.java:58)
> at
> org.apache.lucene.util.TestIOUtils.testSuppressedExceptions(TestIOUtils.java:62)
> ... 26 more
> {noformat}
> For this in Java 7 a new method was added to Throwable, that allows logging
> such suppressed Exceptions (it is called automatically by the synthetic
> bytecode emitted by javac). This patch simply adds this functionality
> conditionally to IOUtils, so it "registers" all suppressed Exceptions, if
> running on Java 7. This is done by reflection: once it looks for this method
> in Throwable.class and if found, it invokes it in closeSafely, so the
> exceptions thrown on Closeable.close() don't get lost.
> This makes debugging much easier and logs all problems that may occur.
> This patch does *not* change functionality or behaviour, it just adds more
> nformation to the stack trace in a Java-7-way (similar to the way how Java
> 1.4 added causes). It works here locally on Java 6 and Java 7, but only Java
> 7 gets the additional stack traces. For Java 6 nothing changes. Same for Java
> 5 (if we backport to 3.x).
> This would be our first Java 7 improvement (a minor one). Next would be
> NIO2... - but thats not easy to do with reflection only, so we have to wait
> 10 years :-)
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