populationhistory.java

java实现的遗传算法

/*
 * This file is part of JGAP.
 *
 * JGAP offers a dual license model containing the LGPL as well as the MPL.
 *
 * For licencing information please see the file license.txt included with JGAP
 * or have a look at the top of class org.jgap.Chromosome which representatively
 * includes the JGAP license policy applicable for any file delivered with JGAP.
 */
package org.jgap.eval;

import java.util.*;
import org.jgap.*;

/**
 * Container for holding a given number of populations. Serves as a history
 * object for later evaluation
 *
 * @author Klaus Meffert
 * @since 2.0
 */
public class PopulationHistory {
  /** String containing the CVS revision. Read out via reflection!*/
  private final static String CVS_REVISION = "$Revision: 1.3 $";

  private List populations;

  private int m_maxSize;

  /**
   * Constructor.
   * @param a_maxSize the maximum number of Population objects to hold, or
   * zero if there is no limit.
   * @author Klaus Meffert
   * @since 2.0
   */
  public PopulationHistory(int a_maxSize) {
    populations = new Vector();
    if (a_maxSize < 0) {
      throw new IllegalArgumentException("Maximum size must be greater"
                                         + " or equal to zero!");
    }
    m_maxSize = a_maxSize;
  }

  public Population getPopulation(int count) {
    return count >= populations.size() ? null :
        (Population) populations.get(count);
  }

  /**
   * Adds a population to the history. If the maximum size of this container
   * is exceeded after that then the oldest population added is removed
   * @param pop the population to be added
   *
   * @author Klaus Meffert
   * @since 2.0
   */
  public void addPopulation(Population pop) {
    populations.add(0, pop);
    int popSize = populations.size();
    if (m_maxSize != 0 && popSize > m_maxSize) {
      populations.remove(popSize - 1);
    }
  }

  /**
   * @author Klaus Meffert
   * @since 2.0
   */
  public void removeAllPopulations() {
    populations.removeAll(populations);
  }

  public int size() {
    return populations.size();
  }

  public List getPopulations() {
    return populations;
  }

  /**
   * Sets the list of populations to the list provided.
   * @param populations list of populations to be set
   *
   * @author Klaus Meffert
   * @since 2.0
   */
  public void setPopulations(List populations) {
    this.populations = populations;
    int popSize = populations.size();
    if (m_maxSize != 0 && popSize > m_maxSize) {
      for (int i = m_maxSize; i < popSize; i++) {
        populations.remove(m_maxSize);
      }
    }
  }
}