src/aco/environment/Environment.java

   1 package aco.environment;
   2
   3 import java.lang.Runtime;
   4 import java.util.SortedMap;
   5 import java.util.Observable;
   6
   7 import aco.ant.*;
   8 import aco.misc.*;
   9 import aco.mediator.*;
  10 import aco.environment.data.*;
  11
  12 public abstract class Environment
  13   extends Observable
  14   implements Runnable {
  15
  16   protected Ant[] ants;
  17   protected ACOMediator acom;
  18   protected EnvironmentData ed;
  19
  20   public Environment(ACOMediator acom) {
  21     this.acom = acom;
  22
  23     this.ants = new Ant[acom.getNumOfAnts()];
  24
  25     for (int i = 0; i < acom.getNumOfAnts(); i++)
  26       ants[i] = new Ant(acom);
  27
  28     this.ed = new EnvironmentData(acom);
  29
  30     /* add a shutdown hook to print out the last best solution */
  31     Runtime.getRuntime().addShutdownHook(new EnvironmentShutdownHook(this));
  32
  33     /* run the garbage collector after all the initialization is done */
  34     System.gc();
  35   }
  36
  37   /* d'tor */
  38   protected void finalize() {
  39     deleteObservers();
  40   }
  41
  42   protected abstract void constructSolutions();
  43
  44   protected abstract boolean terminateCondition(int iteration);
  45
  46   public void run() {
  47     int i = 0;
  48     while ( !terminateCondition(i++) &&
  49         !interruptCondition() ) {
  50       constructSolutions();
  51       updateStatistics(i);
  52       acom.pheromoneUpdate(ants);
  53     }
  54   }
  55
  56   protected boolean interruptCondition() {
  57     return Thread.interrupted();
  58   }
  59
  60   protected void updateStatistics(int iteration) {
  61     for (Ant ant : ants) {
  62
  63       if (ant.getTourLength() < acom.getGlobalBestTourLength()) {
  64         acom.setGlobalBestTourLength(ant.getTourLength());
  65         acom.setGlobalBestTourIteration(iteration);
  66
  67         for (int i = 0; i < acom.getNumOfCities() + 1; i++) {
  68           acom.setGlobalBestTour(i, ant.getTour(i));
  69         }
  70
  71         acom.addGlobalBestTour((Integer)acom.getGlobalBestTourLength(),
  72             acom.getGlobalBestTour());
  73
  74         this.setChanged();
  75         this.notifyObservers();
  76
  77         /* since we are already at it.. run the garbage collector */
  78         System.gc();
  79       }
  80
  81     }
  82   }
  83
  84   public int[] getGlobalBestTour() {
  85     return ed.getGlobalBestTour();
  86   }
  87
  88   public int getGlobalBestTour(int index) {
  89     return ed.getGlobalBestTour(index);
  90   }
  91
  92   public void setGlobalBestTour(int[] GlobalBestTour) {
  93     ed.setGlobalBestTour(GlobalBestTour);
  94   }
  95
  96   public void setGlobalBestTour(int index, int GlobalBestTour) {
  97     ed.setGlobalBestTour(index, GlobalBestTour);
  98   }
  99
 100   public int getGlobalBestTourLength() {
 101     return ed.getGlobalBestTourLength();
 102   }
 103
 104   public void setGlobalBestTourLength(int GlobalBestTourLength) {
 105     ed.setGlobalBestTourLength(GlobalBestTourLength);
 106   }
 107
 108   public int getGlobalBestTourIteration() {
 109     return ed.getGlobalBestTourIteration();
 110   }
 111
 112   public void setGlobalBestTourIteration(int GlobalBestTourIteration) {
 113     ed.setGlobalBestTourIteration(GlobalBestTourIteration);
 114   }
 115
 116   public SortedMap<Integer, int[]> getGlobalBestTourMap() {
 117     return ed.getGlobalBestTourMap();
 118   }
 119
 120   public void addGlobalBestTour(Integer TourLength, int[] Tour) {
 121     ed.addGlobalBestTour(TourLength, Tour);
 122   }
 123
 124   @Override
 125     public String toString() {
 126       StringBuilder result = new StringBuilder();
 127
 128       result.append("Shortest tour at iteration " +
 129           acom.getGlobalBestTourIteration() +
 130           " with length " +
 131           acom.getGlobalBestTourLength() +
 132           "\n");
 133
 134       for (int t : acom.getGlobalBestTour())
 135         result.append(t + " -- ");
 136
 137       result.delete(result.lastIndexOf(" -- "), result.length());
 138
 139       int i = 0;
 140       for (int t : acom.getGlobalBestTour()) {
 141         i = 0;
 142         /* necessary for loop so that we don't check the last city
 143          * which is equal to the first one */
 144         for (int c = 0; c < acom.getNumOfCities(); c++)
 145           if (acom.getGlobalBestTour(c) == t && i++ > 0)
 146             result.append("\n" + "crossed " + c + " more than once!");
 147       }
 148
 149       return result.toString();
 150     }
 151
 152 }