1 /*
2 * Licensed to the Apache Software Foundation (ASF) under one or more
3 * contributor license agreements. See the NOTICE file distributed with
4 * this work for additional information regarding copyright ownership.
5 * The ASF licenses this file to You under the Apache License, Version 2.0
6 * (the "License"); you may not use this file except in compliance with
7 * the License. You may obtain a copy of the License at
8 *
9 * http://www.apache.org/licenses/LICENSE-2.0
10 *
11 * Unless required by applicable law or agreed to in writing, software
12 * distributed under the License is distributed on an "AS IS" BASIS,
13 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
14 * See the License for the specific language governing permissions and
15 * limitations under the License.
16 */
17 package org.apache.commons.math.genetics;
18
19 import java.util.ArrayList;
20 import java.util.Iterator;
21 import java.util.List;
22
23 /**
24 * Population of chromosomes represented by a {@link List}.
25 *
26 * @since 2.0
27 * @version $Revision: 799857 $ $Date: 2009-08-01 09:07:12 -0400 (Sat, 01 Aug 2009) $
28 */
29 public abstract class ListPopulation implements Population {
30
31 /** List of chromosomes */
32 private List<Chromosome> chromosomes;
33
34 /** maximial size of the population */
35 private int populationLimit;
36
37
38 /**
39 * Creates a new ListPopulation instance.
40 *
41 * @param chromosomes list of chromosomes in the population
42 * @param populationLimit maximal size of the population
43 */
44 public ListPopulation (List<Chromosome> chromosomes, int populationLimit) {
45 if (chromosomes.size() > populationLimit) {
46 throw new IllegalArgumentException("List of chromosomes bigger than maxPopulationSize.");
47 }
48 if (populationLimit < 0) {
49 throw new IllegalArgumentException("Population limit has to be >= 0");
50 }
51
52 this.chromosomes = chromosomes;
53 this.populationLimit = populationLimit;
54 }
55
56 /**
57 * Creates a new ListPopulation instance and initializes its inner
58 * chromosome list.
59 *
60 * @param populationLimit maximal size of the population
61 */
62 public ListPopulation (int populationLimit) {
63 if (populationLimit < 0) {
64 throw new IllegalArgumentException("Population limit has to be >= 0");
65 }
66 this.populationLimit = populationLimit;
67 this.chromosomes = new ArrayList<Chromosome>(populationLimit);
68 }
69
70 /**
71 * Sets the list of chromosomes.
72 * @param chromosomes the list of chromosomes
73 */
74 public void setChromosomes(List<Chromosome> chromosomes) {
75 this.chromosomes = chromosomes;
76 }
77
78 /**
79 * Access the list of chromosomes.
80 * @return the list of chromosomes
81 */
82 public List<Chromosome> getChromosomes() {
83 return chromosomes;
84 }
85
86 /**
87 * Add the given chromosome to the population.
88 * @param chromosome the chromosome to add.
89 */
90 public void addChromosome(Chromosome chromosome) {
91 this.chromosomes.add(chromosome);
92 }
93
94 /**
95 * Access the fittest chromosome in this population.
96 * @return the fittest chromosome.
97 */
98 public Chromosome getFittestChromosome() {
99 // best so far
100 Chromosome bestChromosome = this.chromosomes.get(0);
101 for (Chromosome chromosome : this.chromosomes) {
102 if (chromosome.compareTo(bestChromosome) > 0) {
103 // better chromosome found
104 bestChromosome = chromosome;
105 }
106 }
107 return bestChromosome;
108 }
109
110 /**
111 * Access the maximum population size.
112 * @return the maximum population size.
113 */
114 public int getPopulationLimit() {
115 return this.populationLimit;
116 }
117
118 /**
119 * Sets the maximal population size.
120 * @param populationLimit maximal population size.
121 */
122 public void setPopulationLimit(int populationLimit) {
123 this.populationLimit = populationLimit;
124 }
125
126 /**
127 * Access the current population size.
128 * @return the current population size.
129 */
130 public int getPopulationSize() {
131 return this.chromosomes.size();
132 }
133
134 /**
135 * {@inheritDoc}
136 */
137 @Override
138 public String toString() {
139 return this.chromosomes.toString();
140 }
141
142 /**
143 * Chromosome list iterator
144 *
145 * @return chromosome iterator
146 */
147 public Iterator<Chromosome> iterator() {
148 return chromosomes.iterator();
149 }
150 }