I don't have experience what's the best way in using PB-api in servlets.
But I can give some notes:
- PB instances are pooled and PB.close() close the PB-handle and return the underlying PB instance to pool, thus get a PB instance from the pool (PersistenceBrokerFactory) when you need it and close it immediately after use (with the exception of specific scenarios ;-))
- PB instances are not threadsafe, so make sure that each thread operate on a separate PB instance
Recommend you to ask the user in a new thread about their experience.
regards, Armin
Dirk Manske (Service Respond) wrote:
Hi Armin,
I solved the issue. It was indeed a second broker connection open... (was hard to track...). Anyway, I posted the jdbc connection descriptor settings and the source code. I should mention that we have a PersistenceManagerFactory which will be called on web-app startup and initializes a concrete PersistenceManager (in this case OJB-PB). This object is stored in servlet context and can be retrieved on request. The source code reflects a 1:CN relationship between Activity and Module. Can you advised me, is this the common approach I took or is there a better way? thx, Dirk
<descriptor-repository version="1.0" isolation-level="read-uncommitted" proxy-prefetching-limit="50"> <!-- include all used database connections --> <jdbc-connection-descriptor jcd-alias="default" default-connection="true" platform="Hsqldb" jdbc-level="2.0" driver="org.hsqldb.jdbcDriver" protocol="jdbc" subprotocol="hsqldb:hsql" dbalias="//localhost" username="sa" password="" eager-release="false" batch-mode="false" useAutoCommit="2" ignoreAutoCommitExceptions="false" > <connection-pool maxActive="21" validationQuery="" />
<sequence-manager className="org.apache.ojb.broker.util.sequence.SequenceManagerHighLowImpl"> <attribute attribute-name="grabSize" attribute-value="20"/> <attribute attribute-name="autoNaming" attribute-value="true"/> <attribute attribute-name="globalSequenceId" attribute-value="false"/> <attribute attribute-name="globalSequenceStart" attribute-value="10000"/> </sequence-manager> </jdbc-connection-descriptor>
source:
try{ pm.beginTransaction();
pm.storeObject(activityModel); } catch(Exception e){ //TODO catch-Klausel kommentieren e.printStackTrace();
if(logger.isDebugEnabled()) logger.debug("INSERT Aktivit�t failed."); }
//Attribute f�r TMODUL setzen String moduleId = ((String)PropertyUtils.getSimpleProperty(form, "strModuleId"));
if(moduleId != null && !moduleId.equals("-1")){ try{ //Instanz von ActivityModel mit ActivityId holen object = pm.getObjectId(activityModel); } catch(Exception e){ //TODO catch-Klausel kommentieren e.printStackTrace();
if(logger.isDebugEnabled()) logger.debug("ObjectId could not be retrieved."); }
if(object != null && object instanceof ActivityModel){ activityModel = (ActivityModel)object;
//checkbox auswerten String moduleExclusive = ((String)PropertyUtils.getSimpleProperty(form, "strModuleExclusive"));
if(moduleExclusive == null || moduleExclusive.length()<1) moduleExclusive = "no";
moduleModel = new ModuleModel();
moduleModel.setIntModuleId(Integer.parseInt(moduleId)); moduleModel.setStrModuleExclusive(moduleExclusive); moduleModel.setActivityModel(activityModel); moduleModel.setValidFromTimepoint(activityModel.getValidFromTimepoint()); moduleModel.setVersionNr(0); moduleModel.setValidToTimepoint(activityModel.getValidToTimepoint()); moduleModel.setTimestamp(activityModel.getTimestamp()); moduleModel.setStrUserId(activityModel.getStrUserId()); moduleModel.setStrProgram(Constant.PROGRAM_NAME); } }
try{ if(moduleModel != null){ pm.storeObject(moduleModel); }
pm.commitTransaction();
pm.close(); } catch(Exception e){ //TODO catch-Klausel kommentieren e.printStackTrace();
pm.rollbackTransaction();
if(logger.isDebugEnabled()) logger.debug("INSERT Activity/Module failed. Transaction rolled back.");
return
(mapping.findForward(Constant.DATABASE_ERROR_INSERT));
}
finally{
pm.close();
}
-----Urspr�ngliche Nachricht-----
Von: Armin Waibel [mailto:[EMAIL PROTECTED] Gesendet: Dienstag, 30. Dezember 2003 16:57
An: OJB Users List
Betreff: Re: AW: AW: how can i do multiple operations in one transaction?
more questions:
Armin Waibel wrote:
Hi Dirk,
I can't believe that PB-api is the problem. Can you post a junit test (or a modified test from test suite) to reproduce the problem?
What calculations you are doing, do you use the ConnectionManager? Do you set eager-release 'true' in jdbc-connection-descriptor? Do you use batch mode?
Could it be a multithreaded problem? Do you lookup the PB instance twice in your code?
Armin
regards, Armin
Dirk Manske (Service Respond) wrote:
Hi Armin,
no, as ConnectionFactoryClass I use ConnectionFactoryPooledImpl. While the process runs there is only one OJB object (the pm object, see code
snippet)
and I do not use further data sources. All database operations are only handled by PB.
greets,
Dirk
-----Urspr�ngliche Nachricht-----
Von: Armin Waibel [mailto:[EMAIL PROTECTED] Gesendet: Dienstag, 30. Dezember 2003 16:18
An: OJB Users List
Betreff: Re: AW: how can i do multiple operations in one transaction?
Hi Dirk,
hmm, this shouldn't be a problem. Do you use any connection object from OJB while performing your test?
Do you use ConnectionFactoryManagedImpl in OJB.properties file as ConnectionFactoryClass?
Do you use DataSource?
regards, Armin
Dirk Manske (Service Respond) wrote:
Hi Wally,
auto-commit is set to "2" = off. I still get an
org.apache.ojb.broker.TransactionNotInProgressException: ConnectionManager is NOT in transaction. This exception is thrown after pm.commitTransaction() is executed. However, if I comment this out, it runs well, both objects are stored. I really got stucked on this.
Any idea?
thx, Dirk
-----Urspr�ngliche Nachricht----- Von: Gelhar, Wallace Joseph [mailto:[EMAIL PROTECTED] Gesendet: Dienstag, 30. Dezember 2003 05:07 An: OJB Users List Betreff: RE: how can i do multiple operations in one transaction?
Hi Dirk,
PB transactions are database transactions (as opposed to the object level transactions provided by ODMG, OTM, and JDO). Check your database connection descriptor to make sure you have autocommit turned off. I suspect that the JDBC connection is autocommiting the transaction for you on the store operation.
Wally
-----Original Message----- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] Sent: Monday, December 29, 2003 6:27 PM To: [EMAIL PROTECTED] Subject: how can i do multiple operations in one transaction?
Hi,
I am using the PersistenceBroker (OJB 1.0 rc5) and have some problems to store 2 objects within a single transaction. The problem is, that I want to have the whole transaction comitted if and only if a calculation between these two store operations has been successfull, otherwise the first store operation will be rolled back. Consider the following code
snippet:
try{ pm = PersistenceBrokerFactory.defaultPersistenceBroker();
pm.beginTransaction(); pm.store(object1); } catch ...
followed by some calculations then retrieve the first object to get the id (which was set by OJB via autoincrement) ...
try{ pm.getObjectId(object1); } catch ...
follwed by another operation and if succeeded then store object2 and finish the transaction:
try{ pm.store(object2); pm.comitTransaction(); pm.close(); } catch...
I always get a TransactionNotInProgressException. How can I solve this problem?
thx, Dirk
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