User-Defined Key Generator

[ojb ojb]

Hi everybody,

I'm just playing around with a user-defined key generator. I'm having a query, and 
since there is a value "0" (zero) for some key, the OJB key generator starts to 
trigger (well, actually this is not nice, but it helps me testing my generator anyhow).

So, here's the question:
(1) during my query, I see several of these:

[org.apache.ojb.broker.ta.PersistenceBrokerFactoryDefaultImpl] INFO: Already created 
persistence broker instances: 1

[org.apache.ojb.broker.ta.PersistenceBrokerFactoryDefaultImpl] INFO: Already created 
persistence broker instances: 2

[org.apache.ojb.broker.ta.PersistenceBrokerFactoryDefaultImpl] INFO: Already created 
persistence broker instances: 3

Why? Can't he use just one PB instance? I'm using the ODMG interfaces, just creating 
one implementation, one database, one transaction and one query...

implementation = OJB.getInstance();
database = implementation.newDatabase();
try
{
        database.open(configuration, Database.OPEN_READ_WRITE);
} catch (ODMGException ex)
{
        ...
}
... tx open ...
impl.newTransaction()
EnhancedOQLQuery query = db.getImplementation().newOQLQuery();
query.create("select p from a.b.c.DEF");
DList result = (DList) query.execute();

(2) Inside my Key Generator, I am always getting a different PBroker than the one that 
read the query. This causes a second database to be opened. Why/can I configure to use 
the same connection?

Here's the generator:

import org.apache.ojb.broker.util.sequence.SequenceManager;
import org.apache.ojb.broker.util.configuration.Configurable;
import org.apache.ojb.broker.util.configuration.Configuration;
import org.apache.ojb.broker.PersistenceBroker;
import java.sql.Statement;
import org.apache.ojb.broker.metadata.ClassDescriptor;
import org.apache.ojb.broker.query.Query;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.util.logging.Level;
import java.util.logging.Logger;
import org.apache.ojb.broker.util.sequence.SequenceConfiguration;
import org.apache.ojb.broker.PBKey;
import org.apache.ojb.broker.PersistenceBrokerFactory;

public class OJBHiLoSequenceImpl implements SequenceManager, Configurable {

    private static final String STMT_SELECT_1 = "SELECT MAX(";
    private static final String STMT_SELECT_2 = ") FROM ";

        protected static Logger logger = Logger.getLogger("plexx.testsuite");

    private PBKey pbKey;
    private PersistenceBroker brokerForClass;

    public OJBHiLoSequenceImpl(PersistenceBroker broker)
    {
        logger.log(Level.FINEST, "<init> with broker " + broker);
        this.brokerForClass = broker;
    }

    public int getUniqueId(Class par1, String par2) {
        ClassDescriptor cld = brokerForClass.getClassDescriptor(par1);
        // [TP] 2002-11-18 TODO care about multiple table mappings and inheritance 
mappings
                String tableName = cld.getFullTableName();
                String fieldName = cld.getFieldDescriptorByName(par2).getColumnName();
        Statement stmt = null;
        ResultSet set = null;
        try
        {
            PersistenceBroker brokerForSeq = null;
                        // [TP] 2002-11-14 if we have a so-called extra broker key, we 
should
            // [TP] 2002-11-14 use this instance to ask for a connection (key
            // [TP] 2002-11-14 passed during config)
            if (pbKey == null)
            {
                brokerForSeq = PersistenceBrokerFactory.defaultPersistenceBroker();
            } else
            {
                brokerForSeq = PersistenceBrokerFactory.createPersistenceBroker(pbKey);
            }
            logger.log(Level.FINEST, "getUniqueId: using broker " + brokerForSeq);
                        stmt = 
brokerForSeq.getStatementManager().getGenericStatement(cld, Query.NOT_SCROLLABLE);
            set = stmt.executeQuery( STMT_SELECT_1 + fieldName + STMT_SELECT_2 + 
tableName);
                        if (set.next())
            {
                return set.getInt(1);
            } else
            {
                throw new SQLException("Empty result set for table " + tableName + " 
and field " + fieldName);
            }
        } catch (SQLException ex)
        {
            // [TP] 2002-11-18 TODO EX
            throw new RuntimeException(ex);
        }
    }

    public long getUniqueLong(Class par1, String par2){
        return new Long(getUniqueId(par1, par2)).longValue();
    }

    public String getUniqueString(Class par1, String par2){
        return Integer.toString(getUniqueId(par1, par2));
    }

    public Object getUniqueObject(Class par1, String par2){
        return new Integer(getUniqueId(par1, par2));
    }

    public void configure(Configuration par1){
        SequenceConfiguration conf = (SequenceConfiguration) par1;
        this.pbKey = conf.getSeparatePBKey();
    }
}




I know this is a lot of code, but if anybody has a glue - I would be happy.

Thanks for all,

Thomas


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