PDAXCallbackFactory.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.parser.pdax;

import edu.isi.pegasus.planner.classes.PlannerOptions;

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

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




/**
 * A factory class to load the appropriate DAX callback implementations that need
 * to be passed to the DAX Parser.
 *
 * @author Karan Vahi
 * @version $Revision$
 */
public class PDAXCallbackFactory {

    /**
     * Package to prefix "just" class names with.
     */
    public static final String DEFAULT_PACKAGE_NAME =
                                             "edu.isi.pegasus.planner.parser.pdax";

    /**
     * Loads the implementing class corresponding to the type specified by the user.
     * The properties object passed should not be null. The callback that is
     * loaded, is the one referred to in the properties by the user.
     *
     * @param directory  the base level directory in which the output files are
     *                   to be generated.
     * @param properties the <code>PegasusProperties</code> object containing all
     *                   the properties required by Pegasus.
     *
     * @return the instance of the class implementing this interface.
     *
     * @exception PDAXCallbackFactoryException that nests any error that
     *            might occur during the instantiation
     *
     * @see #DEFAULT_PACKAGE_NAME
     * @see org.griphyn.cPlanner.common.PegasusProperties#getPartitionerDAXCallback() 
     */
    public static Callback loadInstance(PegasusProperties properties,
                                        PlannerOptions options,
                                        String directory)
        throws PDAXCallbackFactoryException{

        String mode = options.getMegaDAGMode();
        if(mode == null || mode.equalsIgnoreCase("dag")){
            //load the default one
            mode = "PDAX2MDAG";
        }
        else if(mode.equalsIgnoreCase("noop")){
            mode =  "PDAX2NOOP";
        }
        else if(mode.equalsIgnoreCase("daglite")){
            mode =  "PDAX2DAGLite";
        }
        //load the class stored in the mode
        return loadInstance(properties,options,directory,mode);
    }


    /**
     * Loads the implementing class corresponding to the type specified by the user.
     * The properties object passed should not be null. The callback that is
     * loaded, is the one referred to by the className parameter passed.
     *
     * @param properties the <code>PegasusProperties</code> object containing all
     *                   the properties required by Pegasus.
     *                   dag|noop|daglite.
     * @param options    the <code>PlannerOptions</code> object containing the
     *                   options passed to gencdag.
     * @param directory  the directory where the pdax file and parititioned daxes
     *                   reside.
     * @param className  the name of the implementing class.
     *
     * @return the instance of the class implementing this interface.
     *
     * @exception PDAXCallbackFactoryException that nests any error that
     *            might occur during the instantiation
     *
     * @see #DEFAULT_PACKAGE_NAME
     */
    public static  Callback loadInstance(PegasusProperties properties,
                                         PlannerOptions options,
                                         String directory,
                                         String className)
        throws PDAXCallbackFactoryException{

        Callback callback = null;

        try{

            //sanity check
            if(properties == null){
                throw new RuntimeException("Invalid properties passed");
            }
            if(className == null){
                return loadInstance(properties,options,directory);
            }

            //prepend the package name
            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);
            Object argList[] = new Object[3];
            argList[0] = directory;
            argList[1] = properties;
            argList[2] = options;
            callback = (Callback) dl.instantiate(argList);
        }
        catch( Exception e ){
            throw new PDAXCallbackFactoryException("Instantiating PDAXCallback ",
                                                    className,
                                                    e);
        }

        return callback;
    }


}