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Java > Open Source Codes > examples > gp > anttrail > IfFoodAheadRight


1 /*
2  * This file is part of JGAP.
3  *
4  * JGAP offers a dual license model containing the LGPL as well as the MPL.
5  *
6  * For licencing information please see the file license.txt included with JGAP
7  * or have a look at the top of class org.jgap.Chromosome which representatively
8  * includes the JGAP license policy applicable for any file delivered with JGAP.
9  */
10 package examples.gp.anttrail;
11
12 import org.jgap.*;
13 import org.jgap.gp.*;
14 import org.jgap.gp.impl.*;
15
16 /**
17  * If food-ahead to the right then execute <child 0> else execute <child 1>.
18  *
19  * @author Klaus Meffert
20  * @since 3.01
21  */
22 public class IfFoodAheadRight
23     extends AntCommand {
24   /** String containing the CVS revision. Read out via reflection!*/
25   private final static String JavaDoc CVS_REVISION = "$Revision: 1.3 $";
26
27   private int m_lookAheadFields;
28
29   /**
30    * Looks ahead 1 field to the right.
31    *
32    * @param a_conf the configuration to use
33    * @throws InvalidConfigurationException
34    *
35    * @author Klaus Meffert
36    * @since 3.01
37    */
38   public IfFoodAheadRight(final GPConfiguration a_conf)
39       throws InvalidConfigurationException {
40     this(a_conf, 1);
41   }
42
43   /**
44    * Allows to specify how many fields to look ahead to the right.
45    *
46    * @param a_conf the configuration to use
47    * @param a_lookAheadFields look ahead n fields
48    *
49    * @throws InvalidConfigurationException
50    *
51    * @author Klaus Meffert
52    * @since 3.01
53    */
54   public IfFoodAheadRight(final GPConfiguration a_conf, int a_lookAheadFields)
55       throws InvalidConfigurationException {
56     super(a_conf, 2, CommandGene.VoidClass);
57     m_lookAheadFields = a_lookAheadFields;
58   }
59
60   public CommandGene applyMutation(int index, double a_percentage)
61       throws InvalidConfigurationException {
62     IfFoodAheadLeft mutant = new IfFoodAheadLeft(getGPConfiguration(),
63         m_lookAheadFields);
64     return mutant;
65   }
66
67   public void execute_void(ProgramChromosome a_chrom, int a_n, Object JavaDoc[] a_args) {
68     AntMap map = getMap(a_chrom);
69     int x = map.getPosX();
70     int y = map.getPosY();
71     int orient = map.getOrientation();
72     int cell = AntMap.ERROR;
73     switch (orient) {
74       case AntMap.O_DOWN:
75         if (y >= map.getHeight() - m_lookAheadFields || x < m_lookAheadFields) {
76           cell = AntMap.EMPTY;
77         }
78         else {
79           cell = map.getFromMap(x - m_lookAheadFields, y + m_lookAheadFields);
80         }
81         break;
82       case AntMap.O_LEFT:
83         if (x < m_lookAheadFields || y < m_lookAheadFields) {
84           cell = AntMap.EMPTY;
85         }
86         else {
87           cell = map.getFromMap(x - m_lookAheadFields, y - m_lookAheadFields);
88         }
89         break;
90       case AntMap.O_RIGHT:
91         if (x >= map.getWidth() - m_lookAheadFields ||
92             y >= map.getHeight() - m_lookAheadFields) {
93           cell = AntMap.EMPTY;
94         }
95         else {
96           cell = map.getFromMap(x + m_lookAheadFields, y + m_lookAheadFields);
97         }
98         break;
99       case AntMap.O_UP:
100         if (y < m_lookAheadFields || x >= map.getWidth() - m_lookAheadFields) {
101           cell = AntMap.EMPTY;
102         }
103         else {
104           cell = map.getFromMap(x + m_lookAheadFields, y - m_lookAheadFields);
105         }
106         break;
107     }
108     if (cell == AntMap.ERROR) {
109       throw new IllegalStateException JavaDoc("IfFoodAheadRight: illegal cell content");
110     }
111     if (cell == AntMap.FOOD) {
112       a_chrom.execute_void(a_n, 0, a_args);
113     }
114     else {
115       a_chrom.execute_void(a_n, 1, a_args);
116     }
117   }
118
119   public String JavaDoc toString() {
120     if (m_lookAheadFields == 1) {
121       return "if-food-ahead-right (&1) else (&2)";
122     }
123     else {
124       return "if-food-ahead-right(" + m_lookAheadFields + ") (&1) else (&2)";
125     }
126   }
127 }
128
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