source: liacs/TOOS2010/assignment2/src/Census.java@ 250

package nl.rickvanderzwet.toos.assignment1;

import java.util.Calendar;
import java.util.HashSet;
import java.util.Enumeration;

import nl.rickvanderzwet.toos.assignment1.Voter;

import org.apache.log4j.BasicConfigurator;
import org.apache.log4j.Logger;

public class Census {
  static Logger logger = Logger.getLogger(Census.class);
  public static void main(String[] args) {
  }
  /**
   * Calculates the end-vote for a list of voters, given a certain set of
   * creteria's 
   * @pre-conditions:
   *   - All voters present needs to have a vote set.
   *   - Voter.getVote() needs to be of type Boolean
   * @post-conditions:
   *   - No voter is allowed more than one time on the list.
   * 
   * @return boolean with conjuction of voters or null on error.
   */
  public Boolean census(HashSet<Voter> voters) {
    logger.debug("Starting new comparison");

    /* Nobody likes voting on Tuesday don't they? */
    Calendar rightNow = Calendar.getInstance();
    if (rightNow.get(Calendar.DAY_OF_WEEK) == Calendar.WEDNESDAY) {
      logger.debug("Sorry not today");
      return false;
    }

    /* No voters return error as result cannot be conclusive */
    if (voters == null) {
      return null;
    }

    /* Check all votes to make it a fair voting system */
    for (Voter v: voters) {
      /* Some vote is not set correctly or of wrong return value */
      if (v == null || v.getVote() == null || (!(v.getVote() instanceof Boolean))) { 
        return null;
      }

      logger.debug(v.getVote());
      /* All has to be in agreement */
      if (v.getVote() == false) {
        return false;
      }
    }

    return true;
  }
}