001    package ifs.termination;
002    
003    import ifs.solution.Solution;
004    import ifs.util.DataProperties;
005    
006    /**
007     * General implementation of termination condition.
008     * <br><br>
009     * Solver stops when the solution is complete (all varaibles are assigned) or when a timeout
010     * is reached (expressed either by the number of iterations or by a time).
011     * <br><br>
012     * Parameters:
013     * <br>
014     * <table border='1'><tr><th>Parameter</th><th>Type</th><th>Comment</th></tr>
015     * <tr><td>Termination.StopWhenComplete</td><td>{@link Double}</td><td>if true, solver stops when a complete solution is found</td></tr>
016     * <tr><td>Termination.MaxIters</td><td>{@link Integer}</td><td>if zero or positive, solver stops when the given number of iteration is reached</td></tr>
017     * <tr><td>Termination.TimeOut</td><td>{@link Double}</td><td>if zero or positive, solver stops when the given timeout (given in seconds) is reached</td></tr>
018     * </table>
019     *
020     * @see ifs.solver.Solver
021     *
022     * @author <a href="mailto:muller@ktiml.mff.cuni.cz">Tomáš Müller</a>
023     * @version 1.0
024     **/
025    public class GeneralTerminationCondition implements TerminationCondition {
026        protected static org.apache.log4j.Logger sLogger = org.apache.log4j.Logger.getLogger(GeneralTerminationCondition.class);
027        private int iMaxIter;
028        private double iTimeOut;
029        private boolean iStopWhenComplete;
030        
031        public GeneralTerminationCondition(DataProperties properties) {
032            iMaxIter = properties.getPropertyInt("Termination.MaxIters",-1);
033            iTimeOut = properties.getPropertyDouble("Termination.TimeOut",  -1.0);
034            iStopWhenComplete = properties.getPropertyBoolean("Termination.StopWhenComplete", false);
035        }
036        
037        public boolean canContinue(Solution currentSolution) {
038            if (iMaxIter>=0 && currentSolution.getIteration()>=iMaxIter) {
039                sLogger.info("Maximum number of iteration reached.");
040                return false;
041            }
042            if (iTimeOut>=0 && currentSolution.getTime()>iTimeOut) {
043                sLogger.info("Timeout reached.");
044                return false;
045            }
046            if (iStopWhenComplete || (iMaxIter<0 && iTimeOut<0)) {
047                boolean ret = (!currentSolution.getModel().unassignedVariables().isEmpty());
048                if (!ret) sLogger.info("Complete solution found.");
049                return ret;
050            }
051            return true;
052        }
053    }