Java Tutorial/Design Pattern/Builder Pattern

Builder pattern: build a house

import java.util.LinkedList;
import java.util.List;
public class BuilderDemo {
  public static void main(String[] args) {
    HouseBuilder builder = new SimpleHouseBuilder();
    HouseBuildingCompany houseBuildingCompany = new HouseBuildingCompany();
    House house = houseBuildingCompany.build(builder);
    System.out.println(house);
  }
}
interface HouseBuilder {
  void buildBasement();
  void buildWalls();
  void buildRoof();
  House getHouse();
}
class HouseBuildingCompany {
  public House build(HouseBuilder builder) {
    builder.buildBasement();
    builder.buildWalls();
    builder.buildRoof();
    return builder.getHouse();
  }
}
class SimpleHouseBuilder implements HouseBuilder {
  private House house;
  public SimpleHouseBuilder() {
    this.house = new House();
  }
  public void buildBasement() {
    this.house.setBasement(new Basement());
  }
  public void buildWalls() {
    for (int i = 0; i < 4; i++)
      this.house.addWall(new Wall());
  }
  public void buildRoof() {
    this.house.setRoot(new Roof());
  }
  public House getHouse() {
    return this.house;
  }
}
class Basement {
  @Override
  public String toString() {
    return "Basement";
  }
}
class Wall {
  @Override
  public String toString() {
    return "Wall";
  }
}
class Roof {
  @Override
  public String toString() {
    return "Roof";
  }
}
class House {
  private Basement basement;
  private List<Wall> walls;
  private Roof roof;
  public House() {
    this.walls = new LinkedList<Wall>();
  }
  public void addWall(Wall wall) {
    this.walls.add(wall);
  }
  public void setRoot(Roof roof) {
    this.roof = roof;
  }
  public void setBasement(Basement basement) {
    this.basement = basement;
  }
  @Override
  public String toString() {
    return "House {" + this.basement + ", " + this.walls + ", " + this.roof + "}";
  }
}

Builder pattern with interface

import java.util.ArrayList;
import java.util.Iterator;
public class TestRobotBuilder {
  public static void main(String args[]) {
    Machine builder;
    RobotBuildable robot;
    String response = "a";
    builder = new Cooker();
    // builder = new AutomotiveRobotBuilder();
    // Start the construction process.
    builder.addStart();
    builder.addTest();
    builder.addAssemble();
    builder.addStop();
    robot = builder.getRobot();
    robot.go();
  }
}
interface Machine {
  public void addStart();
  public void addGetParts();
  public void addAssemble();
  public void addTest();
  public void addStop();
  public RobotBuildable getRobot();
}
interface RobotBuildable {
  public void go();
}
class Cooker implements Machine {
  CookerBuildable robot;
  ArrayList<Integer> actions;
  public Cooker() {
    robot = new CookerBuildable();
    actions = new ArrayList<Integer>();
  }
  public void addStart() {
    actions.add(new Integer(1));
  }
  public void addGetParts() {
    actions.add(new Integer(2));
  }
  public void addAssemble() {
    actions.add(new Integer(3));
  }
  public void addTest() {
    actions.add(new Integer(4));
  }
  public void addStop() {
    actions.add(new Integer(5));
  }
  public RobotBuildable getRobot() {
    robot.loadActions(actions);
    return robot;
  }
}
class Car implements Machine {
  CarBuildable robot;
  ArrayList<Integer> actions;
  public Car() {
    robot = new CarBuildable();
    actions = new ArrayList<Integer>();
  }
  public void addStart() {
    actions.add(new Integer(1));
  }
  public void addGetParts() {
    actions.add(new Integer(2));
  }
  public void addAssemble() {
    actions.add(new Integer(3));
  }
  public void addTest() {
    actions.add(new Integer(4));
  }
  public void addStop() {
    actions.add(new Integer(5));
  }
  public RobotBuildable getRobot() {
    robot.loadActions(actions);
    return robot;
  }
}
class CookerBuildable implements RobotBuildable {
  ArrayList<Integer> actions;
  public CookerBuildable() {
  }
  public final void go() {
    Iterator itr = actions.iterator();
    while (itr.hasNext()) {
      switch ((Integer) itr.next()) {
      case 1:
        start();
        break;
      case 2:
        getParts();
        break;
      case 3:
        assemble();
        break;
      case 4:
        test();
        break;
      case 5:
        stop();
        break;
      }
    }
  }
  public void start() {
    System.out.println("Starting....");
  }
  public void getParts() {
    System.out.println("Getting flour and sugar....");
  }
  public void assemble() {
    System.out.println("Baking a cookie....");
  }
  public void test() {
    System.out.println("Crunching a cookie....");
  }
  public void stop() {
    System.out.println("Stopping....");
  }
  public void loadActions(ArrayList<Integer> a) {
    actions = a;
  }
}
class CarBuildable implements RobotBuildable {
  ArrayList<Integer> actions;
  public CarBuildable() {
  }
  public final void go() {
    Iterator itr = actions.iterator();
    while (itr.hasNext()) {
      switch ((Integer) itr.next()) {
      case 1:
        start();
        break;
      case 2:
        getParts();
        break;
      case 3:
        assemble();
        break;
      case 4:
        test();
        break;
      case 5:
        stop();
        break;
      }
    }
  }
  public void start() {
    System.out.println("Starting....");
  }
  public void getParts() {
    System.out.println("Getting a carburetor....");
  }
  public void assemble() {
    System.out.println("Installing the carburetor....");
  }
  public void test() {
    System.out.println("Revving the engine....");
  }
  public void stop() {
    System.out.println("Stopping....");
  }
  public void loadActions(ArrayList<Integer> a) {
    actions = a;
  }
}

Example of the Builder pattern

import java.util.ArrayList;
import java.util.Arrays;
import java.util.Iterator;
import java.util.List;
class Office extends ArrayList<OfficeUnit> {
}
class Word extends Office {
}
class PPT extends Office {
}
class Excel extends Office {
}
class OfficeUnit {
  private String s;
  public OfficeUnit(String s) {
    this.s = s;
  }
  public String toString() {
    return s;
  }
}
class DocumentPage extends OfficeUnit {
  public DocumentPage(String s) {
    super(s);
  }
}
class PPTSlide extends OfficeUnit {
  public PPTSlide(String s) {
    super(s);
  }
}
class ExcelWorkbook extends OfficeUnit {
  public ExcelWorkbook(String s) {
    super(s);
  }
}
class OfficeBuilder {
  public void buildBase() {
  }
  public void addOfficeUnit(OfficeUnit item) {
  }
  public Office getFinishedMedia() {
    return null;
  }
}
class WordBuilder extends OfficeBuilder {
  private Word b;
  public void buildBase() {
    System.out.println("Building word framework");
    b = new Word();
  }
  public void addOfficeUnit(OfficeUnit chapter) {
    System.out.println("Adding word page " + chapter);
    b.add(chapter);
  }
  public Office getFinishedMedia() {
    return b;
  }
}
class PPTBuilder extends OfficeBuilder {
  private PPT m;
  public void buildBase() {
    System.out.println("Building PPT");
    m = new PPT();
  }
  public void addOfficeUnit(OfficeUnit article) {
    System.out.println("Adding slide" + article);
    m.add(article);
  }
  public Office getFinishedMedia() {
    return m;
  }
}
class ExcelBuilder extends OfficeBuilder {
  private Excel w;
  public void buildBase() {
    System.out.println("Building Excel");
    w = new Excel();
  }
  public void addOfficeUnit(OfficeUnit webItem) {
    System.out.println("Adding workbook" + webItem);
    w.add(webItem);
  }
  public Office getFinishedMedia() {
    return w;
  }
}
class OfficeDirector {
  private OfficeBuilder mb;
  public OfficeDirector(OfficeBuilder mb) {
    this.mb = mb; 
  }
  public Office produceMedia(List input) {
    mb.buildBase();
    for (Iterator it = input.iterator(); it.hasNext();)
      mb.addOfficeUnit((OfficeUnit) it.next());
    return mb.getFinishedMedia();
  }
};
public class BuildOfficeDemo {
  public static void main(String[] args) {
    List input = Arrays.asList(new OfficeUnit[] { new OfficeUnit("item1"), new OfficeUnit("item2"),
        new OfficeUnit("item3"), new OfficeUnit("item4"), });
    OfficeDirector buildBook = new OfficeDirector(new WordBuilder());
    Office word = buildBook.produceMedia(input);
    String result = "word: " + word;
    System.out.println(result);
    OfficeDirector buildMagazine = new OfficeDirector(new PPTBuilder());
    Office ppt = buildMagazine.produceMedia(input);
    result = "PPT: " + ppt;
    System.out.println(result);
    OfficeDirector buildWebSite = new OfficeDirector(new ExcelBuilder());
    Office excel = buildWebSite.produceMedia(input);
    result = "Excel: " + excel;
    System.out.println(result);
  }
}