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Date: Fri, 18 Aug 2006 15:46:49 -0400
From: David Gagnon <dgagnon@siunik.com>
Subject: Re: Updating from ibatis 1.3.1 to 2.1.7 .. should I?
 NullPointerException.  It look like a bug ... (More info on the bug) Please
 confirm:-)
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Hi Christian,

  In fact I don`t want to close them.  Here is the generic code used to 
get the info of a User:

 public Object getObject(DbConnection dbCon, String mapKey, Object 
param, boolean mustFind) throws DatabaseException, SQLException {

        Object result = null;
        boolean handleTransactionLocally = false;
        try {
            if (dbCon == null) {
                handleTransactionLocally = true;
                dbCon = connectionFactory.getConnection();
            }

            sqlMap.setUserConnection(dbCon.getConnection());
            result = sqlMap.queryForObject(mapKey, param);

            if ((result == null) && (mustFind)) {
                throw new DataNotFoundException("Object not found for 
param: (" + param.toString() + ")");
            }
        } catch (SQLException e) {
            if (handleTransactionLocally) {
                
ExceptionAdaptor.instance(exceptionAdaptorKey).getMappedException(e, 
"Unable to get: " + e.getMessage(), true, 
ExceptionAdaptor.ACTION_SEARCH, param);
            } else {
                throw e;
            }
        } finally {
            sqlMap.setUserConnection(null);
            if (dbCon != null)
            dbCon.closeAll(handleTransactionLocally);
        }
        return result;

    }

 The only thing I do is supply the connection to use to ibatis.  This 
way I can enclose the call in a transaction or not.  From what I got 
from Clinton it`s the way to do it.  But if you trace with the debugger 
into the sqlMap.setUserConnection(null) method you will see that the 
state of the object is not OK at the end. 

In fact since a single http request can imply the use of lot of 
different DAOs I will have this method called more than once...

I read what you post but it seems to refer to a ping to test that the 
connection to the db is up.  I'm not sure I understand how it`s related 
to my problem.  If I'm wrong please tell me.  I just want to find an 
answer to my current problem!

Best regars
/David

Poitras Christian wrote:
> I don't think you should try setting and ressetting connection manually.
>
> If you want to reset connections (close/open), use these settings in
> sql-map-config file (under <transactionManager><dataSource>).
>             <property value="${pingquery}" name="Pool.PingQuery"/>
>             <property value="${pingenable}" name="Pool.PingEnabled"/>
>             <property value="${pingoldertime}"
> name="Pool.PingConnectionsOlderThan"/>
> Then set these properties in the properties file referenced by this tag
> in sql-map-config file.
> <properties resource="database.properties"/>
>
> Unless iBatis does something really nasty (probably due to JDBC driver
> and not iBatis) or against what your database expects, you should not
> use these objects.
> I run iBatis from version 2.1 and I have never seen the use of these
> objects.
>
> Christian 
>
> -----Original Message-----
> From: David Gagnon [mailto:dgagnon@siunik.com] 
> Sent: Friday, 18 August 2006 15:06
> To: user-java@ibatis.apache.org
> Subject: Re: Updating from ibatis 1.3.1 to 2.1.7 .. should I?
> NullPointerException. It look like a bug ... (More info on the bug)
> Please confirm:-)
>
> Hi all
>
> Since I haven't hear from you .. I dig more trying to find what wrong or
> what I did wrong and I just get more evidence that is a bug and it seems
> to be a major one?  Since it`s the first time I use this version of
> ibatis and since it`s really basic I do think it`s because I'm missing
> something obvious but I have no idea.  Please look at what I have found:
>
> on the 1 call the following constructor is called: public
> SqlMapSessionImpl(ExtendedSqlMapClient client).  This initialize the
> SessionScope object i.e: setting the sqlMapExecutor, etc.. 
>
> When my code calls: sqlMap.setUserConnection(null); this method should
> reset the connection.  But in fact the state of the SqlMapSessionImpl
> associated with the current thread is compromised because this
> setUserConnection has reseted the sessionScope object (See
> SqlMapExecutorDelegate.setUserProvidedTransaction()) associated with
> this SqlMapSessionImpl and put It back into the pool.  BUT the
> sessionScope is still into the SqlMapSessionImpl (and the
> SqlMapSessionImpl is still Not closed).
>
> When I another call the SqlMapSessionImpl will be reused with the
> sessionScope object that have been reseted: I can see the sqlMapExecutor
> set to null witch is not the case with the first call.
>
>  From there the bug will occurs only if the sqlMapExecutor is involved.
>
> In fact this is still unclear to me but I tried calling 2 times the same
> line of code that calls sqlMap.queryForObject(mapKey, param); But
> without error.  Is the sqlMapExecutor is involved?  Does another
> sqlMapExecutor is used?  I have no Idea.
>
> To reproduce the bug you must use the sqlMap.queryForPaginatedList
> method the second time.  You will get the NullPointerException because
> theSessionScope.sqlMapExecutor is NULL.
>
> In fact if you use the debugger an trace the SqlMapClientImpl object
>
>  private SqlMapSessionImpl getLocalSqlMapSession() {
>     SqlMapSessionImpl sqlMapSession = (SqlMapSessionImpl)
> localSqlMapSession.get();
>     if (sqlMapSession == null || sqlMapSession.isClosed()) {
>       sqlMapSession = new SqlMapSessionImpl(this);
>       localSqlMapSession.set(sqlMapSession);
>     }
>     return sqlMapSession;
>   }
>
>  between the 1 and second call you will that the SessionScope object is
> not consistent.
>
> Hope that help.  Like I said since I'm upgrading and don`t know well
> this version of ibatis I don`t really know what is the best approch to
> fix my problem.  Any help is welcome.
>
> Best Regards
> /David
>
> David Gagnon wrote:
>   
>> Hi all,
>>
>>  I'm pretty sure this is a session problem.  But there is an obscur 
>> point that look to me like a bug.  It's surely not one though.
>>
>> Trying to make the problem simple:
>>
>> On the same http request (so same thread) the following function #1 is
>>     
>
>   
>> called followed by another.  When the fynally is excuted from Function
>>     
>
>   
>> #1.  The sessionScope get reseted and put back into the pool!  But 
>> it's not removed from SqlMapSessionImpl!!
>> When function #2 is called it grab the same SqlMapSessionImpl with the
>>     
>
>   
>> reseted SessionScope and that lead me to a NullPointerException.
>>
>> I suppose my problem is simple to fix .. tanks for your help!  That 
>> will bring me one step far in my upgrade process!
>> Best Regards
>>
>>
>> /David
>>
>>
>>
>>
>>
>> Function #1
>> ------------
>> public Object getObject(DbConnection dbCon, String mapKey, Object 
>> param, boolean mustFind) throws DatabaseException, SQLException {
>>
>>        Object result = null;
>>        boolean handleTransactionLocally = false;
>>        try {
>>            if (dbCon == null) {
>>                handleTransactionLocally = true;
>>                dbCon = connectionFactory.getConnection();
>>                // TODO: check if that really usefull
>>                dbCon.setReadOnlyConnection(true);
>>            }
>>
>> //            MappedStatement statement = 
>> sqlMap.getMappedStatement(mapKey);
>> //            result = 
>> statement.executeQueryForObject(dbCon.getConnection(), param);
>>
>>            sqlMap.setUserConnection(dbCon.getConnection());
>>            result = sqlMap.queryForObject(mapKey, param);
>>
>>            if ((result == null) && (mustFind)) {
>>                throw new DataNotFoundException("Object not found for
>> param: (" + param.toString() + ")");
>>            }
>>        } catch (SQLException e) {
>>            if (handleTransactionLocally) {
>>                
>> ExceptionAdaptor.instance(exceptionAdaptorKey).getMappedException(e,
>> "Unable to get: " + e.getMessage(), true, 
>> ExceptionAdaptor.ACTION_SEARCH, param);
>>            } else {
>>                throw e;
>>            }
>>        } finally {
>>            sqlMap.setUserConnection(null);
>>            if (dbCon != null)
>>            dbCon.closeAll(handleTransactionLocally);
>>        }
>>        return result;
>>
>>    }
>> #Function 2
>> -------
>> public final SearchResult getListDynamicWithRowCount(String mapKey, 
>> String rowCountMapKey, Map param) throws DatabaseException {
>>        PaginatedList paginatedList = null;
>>        Integer nbRows = new Integer(-1);
>>        Integer pageSize = null;
>>        try {
>>            paginatedList = sqlMap.queryForPaginatedList(mapKey, param,
>>     
>
>   
>> pageSize.intValue());
>>
>>
>>        } catch (SQLException e) {
>> //            log.error("Error during sql: " + e.getMessage(), e);
>>            
>> ExceptionAdaptor.instance(exceptionAdaptorKey).getMappedException(e,
>> "getList: " + e.getMessage(), true, ExceptionAdaptor.ACTION_SEARCH, 
>> param);
>>        }
>>
>>        return new SearchResult(paginatedList, nbRows.intValue());
>>    }
>>
>>
>> Exception:
>> java.lang.NullPointerException
>>    at
>> com.ibatis.sqlmap.engine.mapping.statement.PaginatedDataList.getList(P
>> aginatedDataList.java:138)
>>
>>    at
>> com.ibatis.sqlmap.engine.mapping.statement.PaginatedDataList.pageTo(Pa
>> ginatedDataList.java:98)
>>
>>    at
>> com.ibatis.sqlmap.engine.mapping.statement.PaginatedDataList.<init>(Pa
>> ginatedDataList.java:46)
>>
>>    at
>> com.ibatis.sqlmap.engine.impl.SqlMapExecutorDelegate.queryForPaginated
>> List(SqlMapExecutorDelegate.java:667)
>>
>>    at
>> com.ibatis.sqlmap.engine.impl.SqlMapSessionImpl.queryForPaginatedList(
>> SqlMapSessionImpl.java:109)
>>
>>    at
>> com.ibatis.sqlmap.engine.impl.SqlMapClientImpl.queryForPaginatedList(S
>> qlMapClientImpl.java:86)
>>
>>    at
>> com.davecorp.webos.dao.DaoSupport.getListDynamicWithRowCount(DaoSuppor
>> t.java:205)
>>
>>    at
>> com.davecorp.webos.dao.DaoSupport.getListDynamicWithRowCount(DaoSuppor
>> t.java:189)
>>
>>    at
>> com.unik.unikommerce.dao.resource.UkResourceDaoImpl.getResourceListDyn
>> amic(UkResourceDaoImpl.java:585)
>>
>>    at
>> com.unik.unikommerce.dao.resource.UkResourceDaoCachedImpl.getResourceL
>> istDynamic(UkResourceDaoCachedImpl.java:315)
>>
>>    at
>> com.unik.unikommerce.managers.InitUnikommerceApplicationManagerImpl.co
>> nfigureUserSession(InitUnikommerceApplicationManagerImpl.java:50)
>>
>>    at
>> com.davecorp.webos.struts.WindowEnabledRequestProcessor.processRequest
>> Setup(WindowEnabledRequestProcessor.java:265)
>>
>>    at
>> com.davecorp.webos.struts.WindowEnabledRequestProcessor.process(Window
>> EnabledRequestProcessor.java:113)
>>
>>    at
>>
>>     
> org.apache.struts.action.ActionServlet.process(ActionServlet.java:1482)
>   
>>    at
>> org.apache.struts.action.ActionServlet.doPost(ActionServlet.java:525)
>>    at javax.servlet.http.HttpServlet.service(HttpServlet.java:709)
>>    at javax.servlet.http.HttpServlet.service(HttpServlet.java:802)
>>    at
>> org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(Appli
>> cationFilterChain.java:252)
>>
>>    at
>> org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFi
>> lterChain.java:173)
>>
>>    at
>> com.davecorp.webos.servlet.SetCharacterEncodingFilter.doFilter(SetChar
>> acterEncodingFilter.java:141)
>>
>>    at
>> org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(Appli
>> cationFilterChain.java:202)
>>
>>    at
>> org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFi
>> lterChain.java:173)
>>
>>    at
>> org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperVa
>> lve.java:213)
>>
>>    at
>> org.apache.catalina.core.StandardContextValve.invoke(StandardContextVa
>> lve.java:178)
>>
>>    at
>> org.apache.catalina.authenticator.AuthenticatorBase.invoke(Authenticat
>> orBase.java:524)
>>
>>    at
>> org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.ja
>> va:126)
>>
>>    at
>> org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.ja
>> va:105)
>>
>>    at
>> org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValv
>> e.java:107)
>>
>>    at
>> org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java
>> :148)
>>
>>    at
>> org.apache.coyote.http11.Http11Processor.process(Http11Processor.java:
>> 869)
>>
>>    at
>> org.apache.coyote.http11.Http11BaseProtocol$Http11ConnectionHandler.pr
>> ocessConnection(Http11BaseProtocol.java:664)
>>
>>    at
>> org.apache.tomcat.util.net.PoolTcpEndpoint.processSocket(PoolTcpEndpoi
>> nt.java:527)
>>
>>    at
>> org.apache.tomcat.util.net.LeaderFollowerWorkerThread.runIt(LeaderFoll
>> owerWorkerThread.java:80)
>>
>>    at
>> org.apache.tomcat.util.threads.ThreadPool$ControlRunnable.run(ThreadPo
>> ol.java:684)
>>
>>    at java.lang.Thread.run(Unknown Source)
>>
>>
>>
>> #Function from SqlMapSessionImpl
>>
>> private SqlMapSessionImpl getLocalSqlMapSession() {
>>    SqlMapSessionImpl sqlMapSession = (SqlMapSessionImpl) 
>> localSqlMapSession.get();
>>    if (sqlMapSession == null || sqlMapSession.isClosed()) {
>>      sqlMapSession = new SqlMapSessionImpl(this);
>>      localSqlMapSession.set(sqlMapSession);
>>    }
>>    return sqlMapSession;
>>  }
>>
>>
>>
>>
>>
>>
>>
>>
>>     
>
>
>
>
>
>
>