XMLProducerFactory.java

/**
 *  Copyright 2007-2008 University Of Southern California
 *
 *  Licensed under the Apache License, Version 2.0 (the "License");
 *  you may not use this file except in compliance with the License.
 *  You may obtain a copy of the License at
 *
 *  http://www.apache.org/licenses/LICENSE-2.0
 *
 *  Unless required by applicable law or agreed to in writing,
 *  software distributed under the License is distributed on an "AS IS" BASIS,
 *  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 *  See the License for the specific language governing permissions and
 *  limitations under the License.
 */


package edu.isi.pegasus.planner.provenance.pasoa.producer;

import edu.isi.pegasus.planner.common.PegasusProperties;
import edu.isi.pegasus.common.util.DynamicLoader;


import edu.isi.pegasus.planner.provenance.pasoa.XMLProducer;

/**
 *
 * The factory for instantiating an XMLProducer.
 *
 * @author Karan Vahi
 * @version $Revision$
 */
public class XMLProducerFactory {
    /**
     * The default package where all the implementations reside.
     */
    public static final String DEFAULT_PACKAGE_NAME = "edu.isi.pegasus.planner.provenance.pasoa.producer";


    /**
     * The default XML producer implementation to be used.
     */
    public static final String DEFAULT_XML_PRODUCER = "InMemory";


    /**
     * Loads the appropriate XMLProducer on the basis of the property set in the
     * properties.
     *
     *
     * @param properties the <code>PegasusProperties</code> object containing all
     *                   the properties required by Pegasus.
     *
     * @return the instance of the appropriate XML Producer.
     *
     * @throws XMLProducerFactoryException that nests any error that
     *         might occur during the instantiation
     *
     * @see #DEFAULT_PACKAGE_NAME
     */
    public static XMLProducer loadXMLProducer( PegasusProperties properties )
                                              throws XMLProducerFactoryException{


        //sanity check

        String className = DEFAULT_XML_PRODUCER;
        XMLProducer producer = null;
        try{

            //prepend the package name if required
            className = ( className.indexOf('.') == -1 )?
                        //pick up from the default package
                        DEFAULT_PACKAGE_NAME + "." + className:
                        //load directly
                        className;

            //try loading the class dynamically
            DynamicLoader dl = new DynamicLoader( className );
            producer = ( XMLProducer ) dl.instantiate( new Object[0] );
        }
        catch ( Exception e ){
            throw new XMLProducerFactoryException( " Unable to instantiate XMLProducer ",
                                                 className,
                                                 e );
        }
        return producer;
    }


}