Setting up a MultiTenantConnectionProvider using Hibernate 4.2 and Spring 3.1.1

Question

I am currently trying to set up Hibernate for multi tenancy using the seperate Schema aproach.
After working on it for about 2 days now and browsing nearly every source

Answer 1

Ok to wrap this up, here is what I ended up with the following. I use a simple CurrentTenantIdentifierResolver. And Instead of trying to inject the DataSource from somewhere else to my MultiTenantConnectionProviderImpl I create the DataSource (c3p0 ComboPooledDatasource) in the ConnectionProvider and started using only the connections provided by the my ConnectionProvider. So I eliminated the extra DataSource. To make the properties of the DataSource easily configurable I opted to get the configuration data from a properties file.

CurrentTenantIdentifierResolverImpl:

public class CurrentTenantIdentifierResolverImpl implements CurrentTenantIdentifierResolver {


    /**
     * The method returns the RequestServerName as tenantidentifier.
     * If no FacesContext is available null is returned.
     * 
     * @return String tenantIdentifier
     */
    @Override
    public String resolveCurrentTenantIdentifier() {
        if (FacesContext.getCurrentInstance() != null){
            return FacesContext.getCurrentInstance().getExternalContext().getRequestServerName();
        } else {
            return null;
        }
    }

    @Override
    public boolean validateExistingCurrentSessions() {
        return true;
    }

}

MultiTenantConnectionProviderImpl:

Note that the PropertyUtil is just a simple local helper class to fetch my properties. Since it is nothing special I won't include it to not clutter the answer.

public class MultiTenantConnectionProviderImpl implements MultiTenantConnectionProvider  {


    private static final long serialVersionUID = 8074002161278796379L;


    private static Logger log = LoggerFactory.getLogger(MultiTenantConnectionProviderImpl.class );

    private ComboPooledDataSource cpds;

    private Properties properties;

    /**
     * 
     * Constructor. Initializes the ComboPooledDataSource based on the config.properties.
     * 
     * @throws PropertyVetoException
     */
    public MultiTenantConnectionProviderImpl() throws PropertyVetoException {
        log.info("Initializing Connection Pool!");
        properties = new Properties();
        try {
            properties.load(Thread.currentThread().getContextClassLoader().getResourceAsStream("config.properties"));
        } catch (IOException e) {
            throw new RuntimeException(e);
        }
        cpds = new ComboPooledDataSource("Example");
        cpds.setDriverClass(properties.getProperty("jdbc.driver"));
        cpds.setJdbcUrl(properties.getProperty("jdbc.url"));
        cpds.setUser(properties.getProperty("jdbc.user"));
        cpds.setPassword(PropertyUtil.getCredential("jdbc.password"));
        log.info("Connection Pool initialised!");
    }


    @Override
    public Connection getAnyConnection() throws SQLException {
        log.debug("Get Default Connection:::Number of connections (max: busy - idle): {} : {} - {}",new int[]{cpds.getMaxPoolSize(),cpds.getNumBusyConnectionsAllUsers(),cpds.getNumIdleConnectionsAllUsers()});
        if (cpds.getNumConnectionsAllUsers() == cpds.getMaxPoolSize()){
            log.warn("Maximum number of connections opened");
        }
        if (cpds.getNumConnectionsAllUsers() == cpds.getMaxPoolSize() && cpds.getNumIdleConnectionsAllUsers()==0){
            log.error("Connection pool empty!");
        }
        return cpds.getConnection();
    }

    @Override
    public Connection getConnection(String tenantIdentifier) throws SQLException {
        log.debug("Get {} Connection:::Number of connections (max: busy - idle): {} : {} - {}",new Object[]{tenantIdentifier, cpds.getMaxPoolSize(),cpds.getNumBusyConnectionsAllUsers(),cpds.getNumIdleConnectionsAllUsers()});
        if (cpds.getNumConnectionsAllUsers() == cpds.getMaxPoolSize()){
            log.warn("Maximum number of connections opened");
        }
        if (cpds.getNumConnectionsAllUsers() == cpds.getMaxPoolSize() && cpds.getNumIdleConnectionsAllUsers()==0){
            log.error("Connection pool empty!");
        }
        return cpds.getConnection(tenantIdentifier, PropertyUtil.getCredential(tenantIdentifier));
    }

    @Override
    public void releaseAnyConnection(Connection connection) throws SQLException {
        connection.close();
    }

    @Override
    public void releaseConnection(String tenantIdentifier, Connection connection){
        try {
            this.releaseAnyConnection(connection);
        } catch (SQLException e) {
            throw new RuntimeException(e);
        }
    }

    @Override
    public boolean supportsAggressiveRelease() {
        return false;
    }

    @SuppressWarnings("rawtypes")
    @Override
    public boolean isUnwrappableAs(Class unwrapType) {
        return ConnectionProvider.class.equals( unwrapType ) || MultiTenantConnectionProvider.class.equals( unwrapType ) || MultiTenantConnectionProviderImpl.class.isAssignableFrom( unwrapType );
    }

    @SuppressWarnings("unchecked")
    @Override
    public  T unwrap(Class unwrapType) {
        if ( isUnwrappableAs( unwrapType ) ) {
            return (T) this;
        }
        else {
            throw new UnknownUnwrapTypeException( unwrapType );
        }
    }
}

The c3p0 specific config is taken from the c3p0-config.xml:

    
        3
        SELECT 1
        2000
        30
        1
        18000
        30
        1
        50
        true
    

And the db specific properties are provided by a config.properties file:

jdbc.url=
jdbc.driver=
jdbc.dbName=
jdbc.dbowner=
jdbc.username=
jdbc.password=

hibernate.dialect=
hibernate.debug=false

The credentials are fetched in a similar fashion from another file.

Any feedback providing improvements is appreciated.