multiple Databases with ODMG

[Jens Kr�mer]

Hi all,

I'm trying to use the ODMG API with multiple repositories/Databases.
Since OJB.java can only hold one open database per thread I always 
have to call 

((OJB) odmg).setCurrentDatabase (dbIWantToUseNext);

before getting a new Transaction with 
tx = odmg.newTransaction ();

Is there any "best practice" for what I'm trying and/or is it ok the way
I do it at the moment ?

The testcase I've written (see attachment) works so far, but next step
is to get it working with multiple threads...

thanks for any response,

Jens

-- 
Jens Kr�mer
[EMAIL PROTECTED]

package org.apache.ojb.odmg;

import junit.framework.TestCase;

import org.odmg.*;

import org.apache.ojb.broker.PersistenceBrokerFactory;
import org.apache.ojb.broker.singlevm.PersistenceBrokerConfiguration;
import org.apache.ojb.broker.FarAwayClass;

import java.util.List;

/**
 * Test to check support for multiple DB in the ODMG API.
 *
 * @author Jens Kraemer, [EMAIL PROTECTED]
 */
public class MultipleDBTest extends TestCase
{
    private String secondRepository = "repositoryFarAway.xml";
    private String repository;

    protected static String NAME = "ODMG MultipleDBTest";

    public MultipleDBTest(String s)
    {
        super(s);
    }

    protected void setUp() throws Exception
    {
        repository =
                ((PersistenceBrokerConfiguration) PersistenceBrokerFactory
                .getConfigurator()
                .getConfigurationFor(null))
                .getRepositoryFilename();
    }

    protected void tearDown() throws Exception
    {
        super.tearDown();
    }
    
    /**
     * tries to open two databases at the same time
     */
    public void testOpenTwoDatabases () throws Exception
    {
    Implementation odmg = OJB.getInstance ();
    DatabaseImpl db = (DatabaseImpl) odmg.newDatabase ();
    DatabaseImpl dbFarAway = (DatabaseImpl) odmg.newDatabase ();

    try {
        db.open (repository, Database.OPEN_READ_WRITE);
        
        assertTrue ("Database " + db + " could not be opened.", db.isOpen ());
        System.out.println ("opened database " + db + " for repository " + 
repository);
        
        dbFarAway.open (secondRepository, Database.OPEN_READ_WRITE);
        assertTrue ("Database " + dbFarAway + " could not be opened.", 
dbFarAway.isOpen ());
        System.out.println ("opened database " + dbFarAway + " for repository " + 
secondRepository);

        // check if db opened before is still open
        assertTrue ("Database " + db + " not open any more.", db.isOpen ());
    }
    finally {
        if (db != null) {
        db.close ();
        } // end of if (db != null)
        if (dbFarAway != null) {
        dbFarAway.close ();
        } // end of if (db != null)
    } // end of finally
    }

    public void testUseTwoDatabases () throws Exception
    {
    Implementation odmg = OJB.getInstance ();
    DatabaseImpl db = (DatabaseImpl) odmg.newDatabase ();
    DatabaseImpl dbFarAway = (DatabaseImpl) odmg.newDatabase ();

    try {
        dbFarAway.open (secondRepository, Database.OPEN_READ_WRITE);
        db.open (repository, Database.OPEN_READ_WRITE);

        ((OJB) odmg).setCurrentDatabase (dbFarAway);
        Transaction tx = odmg.newTransaction ();
        tx.begin ();
        FarAwayClass fac = getNewFarAwayClass ();
        tx.lock (fac, tx.WRITE);
        tx.commit ();

        ((OJB) odmg).setCurrentDatabase (db);
        tx = odmg.newTransaction ();
        tx.begin ();
        Article article = getNewArticle ();
        tx.lock (article, tx.WRITE);
        tx.commit ();

        ((OJB) odmg).setCurrentDatabase (dbFarAway);
        tx = odmg.newTransaction ();
        tx.begin ();
        OQLQuery q = odmg.newOQLQuery ();
        q.create ("select x from " + FarAwayClass.class.getName () + " where 
name=$1");
        q.bind (NAME);
        List results = (List) q.execute ();
        assertEquals ("expected one instance of FarAwayClass:", 1, results.size ());
        tx.commit ();

        ((OJB) odmg).setCurrentDatabase (db);
        tx = odmg.newTransaction ();
        tx.begin ();
        q = odmg.newOQLQuery ();
        q.create ("select x from " + Article.class.getName () + " where 
articleName=$1");
        q.bind (NAME);
        results = (List) q.execute ();
        assertEquals ("expected one instance of Article:", 1, results.size ());
        tx.commit ();
    }
    finally {
        if (db != null) {
        db.close ();
        } // end of if (db != null)
        if (dbFarAway != null) {
        dbFarAway.close ();
        } // end of if (db != null)
    } // end of finally
    
    }

    protected FarAwayClass getNewFarAwayClass ()
    {
    FarAwayClass retval = new FarAwayClass ();
    retval.setName (NAME);
    return retval;
    }

    protected Article getNewArticle ()
    {
    Article retval = new Article ();
    retval.setArticleName (NAME);
    return retval;
    }
}


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