Hi Brad,
are you able to extract this into simple test program without dependencies to
your application? that would be great.
regards
marcel
Fitzgibbons, Brad wrote:
Yes, it's threadsafe. Each visit to the URL invokes the
resourceQueryAndPrint() method. This method is wrapped in a JTA transaction,
and results in the following actions:
(1) Execute a new SQL query on the JCR session (using spring-modules to
provide session).
(2) Create a new instance of PropertyIterator which wraps the RowIterator
from the query.
(3) Perform the loop as shown and print some of the metadata from each
element in the result set.
(a) Each call to PropertyIterator.hasNext() delegates to
RowIterator.hasNext().
(a) Each call to PropertyIterator.next() will marshall data from the
Row returned by RowIterator.next() into a DTO.
Here's an example of the SQL query (with actual property names and node primary
type changed):
select A,B,C,D from custom_type where (A='A1' or A='A2' or A='A3') and
(contains(B, 'XXX') or contains(C, 'XXX')) order by D
Changing the properties in the select clause or the order by clause (but
leaving the where clause as-is) will sometimes produce iterators that do not
have the hasNext/next behavior I've described.
-----Original Message-----
From: Marcel Reutegger [mailto:[EMAIL PROTECTED]
Sent: Monday, July 14, 2008 8:40 AM
To: [email protected]
Subject: Re: RowIterator.next() fails when hasNext() returns true
Hi,
hmm, let's check something else... what about your class ProfileController, is
it thread-safe? is it possible that two threads concurrently call hasNext/next?
is PropertyIterator in ProfileController an instance variable?
regards
marcel
Fitzgibbons, Brad wrote:
Yes. My loop breaks down to this:
while (iterator.hasNext()) {
Object obj = iterator.next();
...
}
However, if I do this instead I get (what appears to be) "normal" behavior
(except that getSize() is often much less than the actual result set size):
while (iterator.hasNext()) {
try {
Object obj = iterator.next();
} catch (NoSuchElementException excp) { /* masked */ } }
Thanks!
brad
-----Original Message-----
From: Marcel Reutegger [mailto:[EMAIL PROTECTED]
Sent: Monday, July 14, 2008 4:35 AM
To: [email protected]
Subject: Re: RowIterator.next() fails when hasNext() returns true
Hi,
this seems very strange because LazyScoreNodeIterator always pre-fetches the
next node. so whenever you call hasNext() and it returns true
LazyScoreNodeIterator already has the next node and does not have to fetch it
on nextRow().
Can you please double check that you always call hasNext() before you
call
nextRow() ?
regards
marcel
Fitzgibbons, Brad wrote:
I'm running into this problem occasionally resulting in the exception
below. I'm using Jackrabbit 1.4 (with core at 1.4.2). I'm using the
H2PersistenceManager and almost all configuration values are set to
their released default. Document order is turned off so the query is
using a LazyScoreNodeIterator. I'm running in a transactional
environment, and my entire execution flow is contained by a single,
read-only, JTA transaction. The single transaction includes
executing the query and all interactions with the returned
RowIterator. If I ignore the NoSuchElementException's and continue
using the iterator then there are often good results subsequent to
the error. I've noticed that when these errors occur there are often
far more results than are returned by RowIterator.getSize(). I
realize that getSize() is not meant to be an accurate count of all
results, but in most other cases getSize() is greater than the size
of the result set (this may not be helpful). I'm using
a SQL query that involves the CONTAINS constraint (so lucene) and ordering by
jcr:score. Does this warrant a bug submission? Is there any additional
information which might help?
org.springframework.web.util.NestedServletException: Request processing failed;
nested exception is java.util.NoSuchElementException
at
org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:535)
at
org.springframework.web.servlet.FrameworkServlet.doGet(FrameworkServlet.java:453)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:114)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:91)
at
com.caucho.server.dispatch.ServletFilterChain.doFilter(ServletFilterChain.java:103)
at
com.caucho.server.webapp.WebAppFilterChain.doFilter(WebAppFilterChain.java:181)
at
com.caucho.server.dispatch.ServletInvocation.service(ServletInvocation.java:266)
at
com.caucho.server.http.HttpRequest.handleRequest(HttpRequest.java:269)
at com.caucho.server.port.TcpConnection.run(TcpConnection.java:603)
at com.caucho.util.ThreadPool$Item.runTasks(ThreadPool.java:721)
at com.caucho.util.ThreadPool$Item.run(ThreadPool.java:643)
at java.lang.Thread.run(Thread.java:619)
Caused by: java.util.NoSuchElementException
at
org.apache.jackrabbit.core.query.lucene.QueryResultImpl$LazyScoreNodeIterator.getScore(QueryResultImpl.java:351)
at
org.apache.jackrabbit.core.query.lucene.RowIteratorImpl.nextRow(RowIteratorImpl.java:153)
at
com.techtarget.content.data.jcr1.ElementDaoImpl.nextElement(ElementDaoImpl.java:722)
at
com.techtarget.content.data.jcr1.PropertyIterator.next(PropertyIterator.java:47)
at
com.techtarget.content.data.jcr1.PropertyIterator.next(PropertyIterator.java:21)
at
com.techtarget.content.web.controller.ProfileController.resourceQueryAndPrint(ProfileController.java:125)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at
sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
at
sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
at java.lang.reflect.Method.invoke(Method.java:597)
at
org.springframework.web.bind.annotation.support.HandlerMethodInvoker.doInvokeMethod(HandlerMethodInvoker.java:305)
at
org.springframework.web.bind.annotation.support.HandlerMethodInvoker.invokeHandlerMethod(HandlerMethodInvoker.java:131)
at
org.springframework.web.servlet.mvc.annotation.AnnotationMethodHandlerAdapter.invokeHandlerMethod(AnnotationMethodHandlerAdapter.java:308)
at
org.springframework.web.servlet.mvc.annotation.AnnotationMethodHandlerAdapter.handle(AnnotationMethodHandlerAdapter.java:295)
at
org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:874)
at
org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:808)
at
org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:523)
at
org.springframework.web.servlet.FrameworkServlet.doGet(FrameworkServlet.java:453)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:114)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:91)
at
com.caucho.server.dispatch.ServletFilterChain.doFilter(ServletFilterChain.java:103)
at
com.caucho.server.webapp.WebAppFilterChain.doFilter(WebAppFilterChain.java:181)
at
com.caucho.server.dispatch.ServletInvocation.service(ServletInvocation.java:266)
at
com.caucho.server.http.HttpRequest.handleRequest(HttpRequest.java:269)
at com.caucho.server.port.TcpConnection.run(TcpConnection.java:603)
at com.caucho.util.ThreadPool$Item.runTasks(ThreadPool.java:721)
at com.caucho.util.ThreadPool$Item.run(ThreadPool.java:643)
at java.lang.Thread.run(Thread.java:619)
Brad Fitzgibbons
Senior Software Engineer
Tech Target
The Most Targeted IT Media
http://www.techtarget.com/
