com.ciphertool.genetics.algorithms.mutation.cipherkey.RandomValueMutationAlgorithm.java Source code

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Here is the source code for com.ciphertool.genetics.algorithms.mutation.cipherkey.RandomValueMutationAlgorithm.java

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/**
 * Copyright 2015 George Belden
 * 
 * This file is part of ZodiacGenetics.
 * 
 * ZodiacGenetics is free software: you can redistribute it and/or modify it
 * under the terms of the GNU General Public License as published by the Free
 * Software Foundation, either version 3 of the License, or (at your option) any
 * later version.
 * 
 * ZodiacGenetics is distributed in the hope that it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
 * FOR A PARTICULAR PURPOSE. See the GNU General Public License for more
 * details.
 * 
 * You should have received a copy of the GNU General Public License along with
 * ZodiacGenetics. If not, see <http://www.gnu.org/licenses/>.
 */

package com.ciphertool.genetics.algorithms.mutation.cipherkey;

import java.util.Random;
import java.util.Set;

import org.apache.log4j.Logger;
import org.springframework.beans.factory.annotation.Required;

import com.ciphertool.genetics.algorithms.mutation.NonUniformMutationAlgorithm;
import com.ciphertool.genetics.dao.GeneDao;
import com.ciphertool.genetics.entities.KeyedChromosome;

public class RandomValueMutationAlgorithm implements NonUniformMutationAlgorithm<KeyedChromosome<Object>> {
    private static Logger log = Logger.getLogger(RandomValueMutationAlgorithm.class);

    private GeneDao geneDao;
    private Integer maxMutationsPerChromosome;

    @Override
    public void mutateChromosome(KeyedChromosome<Object> chromosome) {
        if (maxMutationsPerChromosome == null) {
            throw new IllegalStateException("The maxMutationsPerChromosome cannot be null.");
        }

        /*
         * Choose a random number of mutations constrained by the configurable
         * max and the total number of genes
         */
        int numMutations = (int) (Math.random() * Math.min(maxMutationsPerChromosome, chromosome.getGenes().size()))
                + 1;

        Set<Object> availableKeys = chromosome.getGenes().keySet();

        for (int i = 0; i < numMutations; i++) {
            // Keep track of the mutated keys
            mutateRandomGene(chromosome, availableKeys);
        }
    }

    /**
     * Performs a genetic mutation of a random Gene of the supplied Chromosome
     * 
     * @param chromosome
     *            the Chromosome to mutate
     * @param availableIndices
     *            the Set of available indices to mutate
     */
    protected void mutateRandomGene(KeyedChromosome<Object> chromosome, Set<Object> availableIndices) {
        if (availableIndices == null || availableIndices.isEmpty()) {
            log.warn(
                    "List of available indices is null or empty.  Unable to find a Gene to mutate.  Returning null.");

            return;
        }

        Random generator = new Random();
        Object[] keys = availableIndices.toArray();

        // Get a random map key
        Object randomKey = keys[generator.nextInt(keys.length)];

        // Replace that map value with a randomly generated Gene
        chromosome.getGenes().put((Object) randomKey, geneDao.findRandomGene(chromosome));

        // Remove the key so that it is not used for mutation again
        availableIndices.remove(randomKey);
    }

    /**
     * @param geneDao
     *            the geneDao to set
     */
    @Required
    public void setGeneDao(GeneDao geneDao) {
        this.geneDao = geneDao;
    }

    @Override
    public void setMaxMutationsPerChromosome(Integer maxMutationsPerChromosome) {
        this.maxMutationsPerChromosome = maxMutationsPerChromosome;
    }
}