straightseeding.java

源码为科学出版社出版的英文<java设计模式>(影印版)所用的所有例子程序

import java.util.*;

public class StraightSeeding
    extends Seeding {

  protected Vector Swimmers;
  protected Swimmer[] asw;
  protected int numLanes;
  protected int[] lanes;
  protected int count;
  protected int numHeats;

  public StraightSeeding(Vector sw, int lanes) {
    Swimmers = sw;
    numLanes = lanes;
    count = sw.size();
    calcLaneOrder();
    seed();
  }

  //--------------------------------
  protected void seed() {
    //loads the asw array and sorts it
    sortUpwards();

    int lastHeat = count % numLanes;
    if (lastHeat < 3) {
      lastHeat = 3; //last heat must have 3 or more
    }
    int lastLanes = count - lastHeat;
    numHeats = count / numLanes;
    if (lastLanes > 0) {
      numHeats++;
    }
    int heats = numHeats;

    //place heat and lane in each swimmer's object
    int j = 0;

    for (int i = 0; i < lastLanes; i++) {
      Swimmer sw = asw[i];

      sw.setLane(lanes[j++]);
      sw.setHeat(heats);
      if (j >= numLanes) {
        heats--;
        j = 0;
      }
    }

    //Add in last partial heat
    if (j < numLanes) {
      heats--;
    }
    j = 0;
    for (int i = lastLanes - 1; i < count; i++) {

      Swimmer sw = asw[i];
      sw.setLane(lanes[j++]);
      sw.setHeat(heats);
    }
    //copy from array back into Vector

    Swimmers = new Vector();
    for (int i = 0; i < count; i++) {
      Swimmers.addElement(asw[i]);

    }
  }

  //--------------------------------
  private void calcLaneOrder() {
    lanes = new int[numLanes];
    int mid = numLanes / 2;
    if (odd(numLanes)) {
      mid = mid + 1; //start in middle lane
    }
    int incr = 1;
    int ln = mid;
    for (int i = 0; i < numLanes; i++) {
      lanes[i] = ln;

      ln = mid + incr;
      incr = -incr;
      if (incr > 0) {
        incr = incr + 1;
      }
    }
  }

  //--------------------------------
  private boolean odd(int x) {
    return ( ( (x / 2) * 2) != x);
  }

  //--------------------------------
  protected void sortUpwards() {
    asw = new Swimmer[count];
    for (int i = 0; i < count; i++) {
      asw[i] = (Swimmer) Swimmers.elementAt(i);
    }
    for (int i = 0; i < count; i++) {
      for (int j = i; j < count; j++) {
        if (asw[i].getTime() > asw[j].getTime()) {
          Swimmer swtemp = asw[i];
          asw[i] = asw[j];
          asw[j] = swtemp;
        }
      }
    }
  }

  //--------------------------------
  public int getCount() {
    return Swimmers.size();
  }

  public Enumeration getSwimmers() {
    return Swimmers.elements();
  }

  //----------------------------------
  public int getHeats() {
    return numHeats;
  }
}