org.objectstyle.cayenne.dba.DbAdapterFactoryChain Maven / Gradle / Ivy

Go to download
Show more of this group Show more artifacts with this name
Show all versions of cayenne-nodeps
Cayenne Object Persistence Framework
There is a newer version: 1.2.4
/* ====================================================================
 *
 * The ObjectStyle Group Software License, version 1.1
 * ObjectStyle Group - http://objectstyle.org/
 * 
 * Copyright (c) 2002-2005, Andrei (Andrus) Adamchik and individual authors
 * of the software. All rights reserved.
 * 
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in
 *    the documentation and/or other materials provided with the
 *    distribution.
 * 
 * 3. The end-user documentation included with the redistribution, if any,
 *    must include the following acknowlegement:
 *    "This product includes software developed by independent contributors
 *    and hosted on ObjectStyle Group web site (http://objectstyle.org/)."
 *    Alternately, this acknowlegement may appear in the software itself,
 *    if and wherever such third-party acknowlegements normally appear.
 * 
 * 4. The names "ObjectStyle Group" and "Cayenne" must not be used to endorse
 *    or promote products derived from this software without prior written
 *    permission. For written permission, email
 *    "andrus at objectstyle dot org".
 * 
 * 5. Products derived from this software may not be called "ObjectStyle"
 *    or "Cayenne", nor may "ObjectStyle" or "Cayenne" appear in their
 *    names without prior written permission.
 * 
 * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED
 * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
 * DISCLAIMED.  IN NO EVENT SHALL THE OBJECTSTYLE GROUP OR
 * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
 * USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
 * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
 * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 * ====================================================================
 * 
 * This software consists of voluntary contributions made by many
 * individuals and hosted on ObjectStyle Group web site.  For more
 * information on the ObjectStyle Group, please see
 * .
 */
package org.objectstyle.cayenne.dba;

import java.sql.DatabaseMetaData;
import java.sql.SQLException;
import java.util.ArrayList;
import java.util.Collection;
import java.util.List;

import org.apache.log4j.Logger;

/**
 * A facade for a collection of DbAdapterFactories. Can be configured to autodetect all
 * adapters known to Cayenne or can work with custom factories.
 * 
 * @since 1.2
 * @author Andrus Adamchik
 */
// TODO, Andrus 11/01/2005, how can custom adapters be autodetected? I.e. is there a way
// to plug a custom factory into configuration loading process? Of course users can simply
// specify the adapter class in the modeler, so this may be a non-issue.
class DbAdapterFactoryChain implements DbAdapterFactory {

    private static final Logger logObj = Logger.getLogger(DbAdapterFactoryChain.class);

    List factories;

    DbAdapterFactoryChain(Collection factories) {
        this.factories = new ArrayList();
        this.factories.addAll(factories);
    }

    /**
     * Iterates through predicated factories, stopping when the first one returns non-null
     * DbAdapter. If none of the factories match the database, returns null.
     */
    public DbAdapter createAdapter(DatabaseMetaData md) throws SQLException {

        if (logObj.isInfoEnabled()) {
            logObj.info("DB name: " + md.getDatabaseProductName());
        }

        // match against configured predicated factories

        // iterate in reverse order to allow custom factories to take precedence over the
        // default ones configured in constructor
        for (int i = factories.size() - 1; i >= 0; i--) {
            DbAdapterFactory factory = (DbAdapterFactory) factories.get(i);
            DbAdapter adapter = factory.createAdapter(md);

            if (adapter != null) {
                return adapter;
            }
        }

        return null;
    }

    /**
     * Removes all configured factories.
     */
    void clearFactories() {
        this.factories.clear();
    }

    /**
     * Adds a new DbAdapterFactory to the factory chain.
     */
    void addFactory(DbAdapterFactory factory) {
        this.factories.add(factory);
    }
}