source: trunk/EventBenchConsole/src/de/ugoe/cs/eventbench/efg/EFGModelGenerator.java

package de.ugoe.cs.eventbench.efg;

import java.util.ArrayList;
import java.util.Collection;
import java.util.LinkedList;
import java.util.List;
import java.util.Random;

import de.ugoe.cs.eventbench.commands.CMDupdateModel;
import de.ugoe.cs.eventbench.data.Event;
import de.ugoe.cs.eventbench.efg.data.EFGEvent;
import de.ugoe.cs.eventbench.models.DeterministicFiniteAutomaton;
import de.ugoe.cs.eventbench.models.FirstOrderMarkovModel;
import edu.umd.cs.guitar.model.GUITARConstants;
import edu.umd.cs.guitar.model.IO;
import edu.umd.cs.guitar.model.data.EFG;
import edu.umd.cs.guitar.model.data.EventGraphType;
import edu.umd.cs.guitar.model.data.EventType;

/**
 * <p>
 * Provides functionality to generates models defined in the package
 * de.ugoe.cs.eventbench.models from EFGs.
 * </p>
 * 
 * @author Steffen Herbold
 * @version 1.0
 */
public class EFGModelGenerator {

        /**
         * <p>
         * Generates a {@link FirstOrderMarkovModel} from an EFG. In the generated
         * model, all following events are equally possible, i.e., the model is
         * equal to a {@link DeterministicFiniteAutomaton}. However, through further
         * training (e.g., {@link CMDupdateModel}) this can be changed.
         * </p>
         * 
         * @param efgFileName
         *            name of the EFG file
         * @return model generated from the EFG
         */
        public FirstOrderMarkovModel efgToFirstOrderMarkovModel(String efgFileName) {
                EFG efg = (EFG) IO.readObjFromFile(efgFileName, EFG.class);

                Collection<List<? extends Event<?>>> subsequences = generateEdgeSequences(efg);
                FirstOrderMarkovModel model = new FirstOrderMarkovModel(new Random());
                model.train(subsequences);
                return model;
        }

        /**
         * <p>
         * Generates a {@link DeterministicFiniteAutomaton} from an EFG.
         * </p>
         * 
         * @param efgFileName
         *            name of the EFG file
         * @return model generated from the EFG
         */
        public DeterministicFiniteAutomaton efgToDeterministicFiniteAutomaton(
                        String efgFileName) {
                EFG efg = (EFG) IO.readObjFromFile(efgFileName, EFG.class);

                Collection<List<? extends Event<?>>> subsequences = generateEdgeSequences(efg);
                DeterministicFiniteAutomaton model = new DeterministicFiniteAutomaton(
                                new Random());
                model.train(subsequences);
                return model;
        }

        /**
         * <p>
         * Extracts the graph structure from the EFG. The result is a set of
         * sequences, where each sequence has length two and represents an edge in
         * the EFG.
         * </p>
         * 
         * @param efg
         *            EFG for which the edge sequence set is generated
         * @return edge sequence set
         */
        private Collection<List<? extends Event<?>>> generateEdgeSequences(EFG efg) {
                List<Event<?>> events = createEvents(efg);
                /*
                 * getEventGraph returns an adjacency matrix, i.e., a square matrix of
                 * efgEvents.size(), where a 1 in row i, column j means an edge
                 * efgEvents.get(i)->efgEvents.get(j) exists.
                 */
                EventGraphType efgGraph = efg.getEventGraph();
                Collection<List<? extends Event<?>>> subsequences = new LinkedList<List<? extends Event<?>>>();

                int efgSize = events.size();
                for (int row = 0; row < efgSize; row++) {
                        for (int col = 0; col < efgSize; col++) {
                                int relation = efgGraph.getRow().get(row).getE().get(col);
                                // otherEvent is followed by currentEvent
                                if (relation != GUITARConstants.NO_EDGE) {
                                        List<Event<?>> edge = new LinkedList<Event<?>>();
                                        edge.add(events.get(row));
                                        edge.add(events.get(col));
                                        subsequences.add(edge);
                                }
                        }
                }
                return subsequences;
        }

        /**
         * <p>
         * Extracts creates {@link EFGEvent} for every event contained in the EFG.
         * </p>
         * 
         * @param efg
         *            EFG for which the events are created
         * @return list of events
         */
        private List<Event<?>> createEvents(EFG efg) {
                List<EventType> efgEvents = efg.getEvents().getEvent();
                List<Event<?>> myEvents = new ArrayList<Event<?>>(efgEvents.size());
                for (EventType event : efgEvents) {
                        /*
                         * the widgetId and eventId are only hash values, the
                         * "interpretation" is found in the GUI file.
                         */
                        Event<?> myEvent = new EFGEvent(event.getEventId());
                        myEvent.setTarget(event.getWidgetId());
                        myEvents.add(myEvent);
                }
                return myEvents;
        }
}