PartialCooperator.java

import java.util.Random;
import java.security.SecureRandom;

/**
 * A subclass of organism that cooperates
 * half of the time.
 * A random field has been added.
 * The methods are changed to suit.
 */
public class PartialCooperator extends Organism {
  //fields--------------------------------------------

  private Random rand; 

  //Constructor---------------------------------------

  public PartialCooperator() {
    super();
    rand = new SecureRandom();
  }

  //Methods-------------------------------------------

  @Override
  public String getType() {
    return "PartialCooperator";
  }

  @Override
  public Organism reproduce() {
    //Check to see whether mutation to Cooperator or Defector occurs
    int mut = rand.nextInt(100);
    if (mut == 0) {
      return new Cooperator();
    } else if (mut == 999) {
      return new Defector();
    } 
    return new PartialCooperator();
  }

  @Override
  public double getCooperationProbability() {
    return .5;
  }

  @Override
  public boolean cooperates() {
    return rand.nextBoolean();
  }
}