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


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 left then execute <child 0> else execute <child 1>.
18  *
19  * @author Klaus Meffert
20  * @since 3.01
21  */
22 public class IfFoodAheadLeft
23     extends AntCommand implements IMutateable {
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 left.
31    *
32    * @param a_conf the configuration to use
33    * @throws InvalidConfigurationException
34    *
35    * @author Klaus Meffert
36    * @since 3.01
37    */
38   public IfFoodAheadLeft(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 left.
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 IfFoodAheadLeft(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     IfFoodAheadRight mutant = new IfFoodAheadRight(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 ||
76             x >= map.getWidth() - m_lookAheadFields) {
77           cell = AntMap.EMPTY;
78         }
79         else {
80           cell = map.getFromMap(x + m_lookAheadFields, y + m_lookAheadFields);
81         }
82         break;
83       case AntMap.O_LEFT:
84         if (x < m_lookAheadFields || y >= map.getHeight() - m_lookAheadFields) {
85           cell = AntMap.EMPTY;
86         }
87         else {
88           cell = map.getFromMap(x - m_lookAheadFields, y + m_lookAheadFields);
89         }
90         break;
91       case AntMap.O_RIGHT:
92         if (x >= map.getWidth() - m_lookAheadFields ||
93             y < m_lookAheadFields) {
94           cell = AntMap.EMPTY;
95         }
96         else {
97           cell = map.getFromMap(x + m_lookAheadFields, y - m_lookAheadFields);
98         }
99         break;
100       case AntMap.O_UP:
101         if (y < m_lookAheadFields || x < m_lookAheadFields) {
102           cell = AntMap.EMPTY;
103         }
104         else {
105           cell = map.getFromMap(x - m_lookAheadFields, y - m_lookAheadFields);
106         }
107         break;
108     }
109     if (cell == AntMap.ERROR) {
110       throw new IllegalStateException JavaDoc("IfFoodAheadLeft: illegal cell content");
111     }
112     if (cell == AntMap.FOOD) {
113       a_chrom.execute_void(a_n, 0, a_args);
114     }
115     else {
116       a_chrom.execute_void(a_n, 1, a_args);
117     }
118   }
119
120   public String JavaDoc toString() {
121     if (m_lookAheadFields == 1) {
122       return "if-food-ahead-left (&1) else (&2)";
123     }
124     else {
125       return "if-food-ahead-left(" + m_lookAheadFields + ") (&1) else (&2)";
126     }
127   }
128 }
129
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