Crash while retrieving Results from a Reportquery and query.setEndAtIndex()

[Christoph Hermann]

Hello,

i'm having Problems when retrieving Results with a Reportquery.
I set the max number of results to 10 and on the 9th row my loop crashes 
(because in the database there are only 8 rows).
I would expect ojb to only return 8 Rows.

Code snippet:

var crit = new Packages.org.apache.ojb.broker.query.Criteria();
 crit.addEqualToField(logs.menuLinkId,id);
 var q = new 
Packages.org.apache.ojb.broker.query.ReportQueryByCriteria(Packages.nymphoon.MenuLink,
 
crit);
  
 var attributes = new Array(3);
 attributes[0] = logs.menuLinkId;
 attributes[1] = count(*);
 attributes[2] = name;
 q.setAttributes(attributes);
 
 q.addGroupBy(logs.menuLinkId);
 q.addGroupBy(name);
 q.addOrderByDescending(count(*));
 q.setEndAtIndex(10);
 
 dao.begin();
 var it = dao.getReport (q);
 while ( it.hasNext() ) {
  var o = it.next(); // crash
  suggestions.add(o);
 }
 dao.commit();


The while loop crashes after the 8th Element.
An Iterator of Type broker.accesslayer.PagingIterator (it) is 
instanciated correctly.
I thought that if there are only 8 Rows it.hasNext() would return false?

I could add a try/catch in the inner loop, but i don't think this is a 
good solution.
Can anyone help me with this?

The loop works fine when i set q.setEndAtIndex(5); i.e.

Christoph


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Getting Started With OJB

[Scott Purcell]

 
I found the object/relational bridge from a Struts book I was reading. The book 
suggested this type of technology, but did not give any information on 
configuring the OJB.
 
So I downloaded the binaries for 1.0.1 and began reading the tutorial. Before I 
get too deep, I just want to be able to do some simple selects/joins for some 
data in a simple web app I am writing using struts.
 
Upon following the docs, I clicked the link for '  
http://db.apache.org/ojb/docu/tutorials/odmg-tutorial.html ODMG Tutorial ' 
and created the Product.java file.  Then I moved to the 'Tutorial Mapping' link 
and created the table product in MYSQL. It then talks about a repository.xml 
doc and a user-repository.xml document. It shows some xml, but I do not know if 
it is the user- or the repository.xml.
 
class-descriptor
   class=org.apache.ojb.tutorials.Product
   table=Product

field-descriptor
   name=id
   column=id
   primarykey=true
   autoincrement=true
/
field-descriptor
   name=name
   column=name
/
field-descriptor
   name=price
   column=price
/
field-descriptor
   name=stock
   column=stock
/
/class-descriptor

I do not know which one the above is and where it should live in my webapp?
And then there is the question of the other xml document.
 
Could someone help me just help me create the proper setup, tell me where 
things live, and get me underway with a select and an update of the simple 
product table?
 
Thanks,
Scott
 
 

Re: Crash while retrieving Results from a Reportquery and query.setEndAtIndex()

[Christoph Hermann]

Jakob Braeuchi schrieb:

Hello,

 what do you mean by 'crash' ? could you please post the exception.

hmm of course, sorry that i forgot this :/

The Exception is:

org.apache.cocoon.ProcessingException: Failed to execute pipeline.: 
java.lang.RuntimeException: java.lang.RuntimeException: 
org.apache.avalon.framework.CascadingRuntimeException: 
file:/usr/local/jakarta-tomcat-4.1.31/webapps/cocoon_2.1.6/samples/guschtel/nymphoon/flow/authentication.js,
 
line 318: uncaught JavaScript exception: at displayMenu 
(file:/usr/local/jakarta-tomcat-4.1.31/webapps/cocoon_2.1.6/samples/guschtel/nymphoon/flow/authentication.js,
 
Line 318): 

java.util.NoSuchElementException: Could not obtain next object: inner 
hasNext was false

317: while ( it.hasNext() ) {
318:   var o = it.next(); // crashes here
319:   suggestions.add(o);
320: }

Christoph


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Re: Crash while retrieving Results from a Reportquery and query.setEndAtIndex()

[Christoph Hermann]

Antonio Gallardo schrieb:

Hello,

 Line 318):
  java.util.NoSuchElementException: Could not obtain next object:
  inner

 hasNext was false

  317: while ( it.hasNext() ) {
  318:   var o = it.next(); // crashes here
  319:   suggestions.add(o);
  320: }

 Thanks. This is inside Cocoon Flow. Seems that OJB has nothing to do
 in this case. Please send more code of this Javascript. I would
 recommend to move this business code to a java code and call it from
 your Flow function. There are some small incompatibilities while
 manipulating Java object inside Javascript.

 I have interest in know how is declared it. Which kind of object it
 is.

Same Thing happens when i use it in a java Class.
Javascript is just easier to Debug for me, because i'm not using a java 
IDE.
My workaround is to put a try/catch block into the while-loop.

My Java-Code:

import java.util.ArrayList;
import java.util.Collection;
import java.util.Iterator;

import java.io.*;
import java.text.*;
import java.util.*;

import org.apache.ojb.broker.query.*;

...

  Criteria crit = new Criteria();
  crit.addEqualToField(logs.menuLinkId,id);
  crit.addEqualToField(stylesheet.id,stylesheetId);
  ReportQueryByCriteria q = new 
ReportQueryByCriteria(MenuLink.class,crit);
 
  String[] attributes = new String[4];
  attributes[0] = logs.menuLinkId;
  attributes[1] = count(*);
  attributes[2] = name;
  attributes[3] = stylesheet.type;
  q.setAttributes(attributes);
  
  q.addGroupBy(logs.menuLinkId);
  q.addGroupBy(name);
  q.addGroupBy(stylesheet.type);
  q.addOrderByDescending(count(*));
  // top 10
  q.setEndAtIndex(10);
 
  ArrayList menulinks = new ArrayList();
  dao.begin();
  Iterator it = dao.getReport (q);
  while ( it != null  it.hasNext() ) {
   // Catch Exception
   try {
Object[] o = (Object[]) it.next();
menulinks.add(o);
   } catch (Exception e) {
//nothing
   }
  }
  dao.commit();

Christoph


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