# GraphDAO.java

    /*
     * Copyright 2011 Marc Grue.
     *
     * 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 org.qi4j.sample.dcicargo.pathfinder_b.internal;

    import java.util.ArrayList;
    import java.util.Arrays;
    import java.util.Collections;
    import java.util.Date;
    import java.util.List;
    import java.util.Random;
    import org.qi4j.sample.dcicargo.pathfinder_b.api.TransitEdge;
    import org.qi4j.sample.dcicargo.pathfinder_b.api.TransitPath;

    public class GraphDAO
    {

        private static final Random random = new Random();
        private static final long ONE_MIN_MS = 1000 * 60;
        private static final long ONE_HOUR_MS = ONE_MIN_MS * 60;
        private static final long ONE_DAY_MS = ONE_HOUR_MS * 24;

        private List<TransitPath> voyages = new ArrayList<TransitPath>();

        public List<String> listLocations()
        {
            return new ArrayList<String>( Arrays.asList(
                "CNHKG", "AUMEL", "SESTO", "FIHEL", "USCHI", "JNTKO", "DEHAM", "CNSHA", "NLRTM", "SEGOT", "CNHGH", "SOMGQ", "USNYC", "USDAL"
            ) );
        }

        public List<TransitPath> voyages()
        {
            if( voyages.size() > 0 )
            {
                return voyages;
            }

            Date departureDate = new Date();
            for( int i = 0; i < 50; i++ )
            {
                List<String> locations = getRandomChunkOfLocations( listLocations() );
                final List<TransitEdge> transitEdges = new ArrayList<TransitEdge>( locations.size() - 1 );
                final String voyageNumber = "V" + ( 101 + i );

                // Origin and destination of voyage schedule
                String from = locations.remove( 0 );
                String destination = locations.remove( 0 );

                Date date = nextDate( departureDate );
                Date fromDate;
                Date toDate;

                // Carrier movements
                for( final String to : locations )
                {
                    fromDate = nextDate( date );
                    toDate = nextDate( fromDate );
                    date = nextDate( toDate );
                    transitEdges.add( new TransitEdge( voyageNumber, from, to, fromDate, toDate ) );

                    // Arrival location of last carrier movement becomes departure location of next
                    from = to;
                }

                // Final carrier movement
                fromDate = nextDate( date );
                toDate = nextDate( fromDate );
                transitEdges.add( new TransitEdge( voyageNumber, from, destination, fromDate, toDate ) );

                voyages.add( new TransitPath( transitEdges ) );
            }

            return voyages;
        }

        private Date nextDate( Date date )
        {
            return new Date( date.getTime() + ONE_DAY_MS + ( random.nextInt( 1000 ) - 500 ) * ONE_MIN_MS );
        }

        private List<String> getRandomChunkOfLocations( List<String> allLocations )
        {
            Collections.shuffle( allLocations );
            final int total = allLocations.size();
            // Including origin and destination
            final int chunk = total > 6 ? 3 + new Random().nextInt( 5 ) : total;
            return allLocations.subList( 0, chunk );
        }
    }