Aggregator.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.namespace.aggregator;


/**
 * An internal interface, that allows us to perform aggregation functions
 * on profiles during merging of profiles.
 *
 * @author Karan Vahi
 * @version $Revision$
 */
public interface Aggregator{

    /**
     * The version number associated with this API of Profile Aggregators.
     */
    public static final String VERSION = "1.0";


    /**
     * Do the aggregation function on the profile values.
     *
     * @param oldValue   the existing value for the profile.
     * @param newValue   the new value being added to the profile.
     * @param dflt       the default value to be used in case the values
     *                   are not of the correct type.
     *
     * @return the computed value as a String.
     */
    public String compute( String oldValue, String newValue, String dflt );
}