Factory Pattern

AbstractFactory.java

package com.example.factory;

public interface CarFactory {
  Car createCar();
}

public FordCarFactory implements CarFactory {
  
  @Override
  public Car createCar() {
    return new FordCar();
  }
}

public ToyotaCarFactory implements CarFactory {
  
  @Override
  public Car createCar() {
    return new ToyotaCar();
  }
}

public Application {
  
  public static void main(String[] args) {
    final CarFactory carFactory = createFactoryFromProperty();
    final Car car = carFactory.createCar();
    System.out.println("I got a new car ! My car model is " + car.getModel());
  }
}

Factory.java

package com.example.factory;

public final class DressFactory {

  public static Dress createDress() {
    if ( isPassedMidnight() ) {
      return new DirtyDress();
    }
    return new PrincessDress();
  }
}

FactoryMethod.java

package com.example.factory;

/**
 * Based on Java's java.util.regex.Pattern implementation
 */
public final class Pattern {

  public enum Flag {
    UNIX_LINES(0x01), 
    CASE_INSENSITIVE(0x02),
    // ... some more constants
    CANON_EQ(0x80);
    
    // methods & fields
  }
  
  public static Pattern compile(String regex, Flag ... flags) {
    int internalFlag = 0;
    for (flag : flags) {
      internalFlag |= flag.value();
    }
    return new Pattern(regex, internalFlag);
  }
    
  private Pattern(String regex, int flag) {
    // initialization code
  }  
  
  /*
   *  rest of class method and members
   */
}