Java - 如何正确结合抽象工厂和工厂方法？

Question

我查看了使用抽象工厂和工厂方法的示例。但是我怎样才能正确地将两者结合起来，所以抽象工厂会选择需要哪个具体工厂，然后工厂方法会选择在给定工厂中创建什么。 我试图让自己成为一个使用这些模式的程序，但陷入了死胡同。无法弄清楚如何正确组合这两种模式以使我的程序正常工作。我的程序非常简单。它只会创建家具 - 桌子或椅子，具体取决于所选的混凝土工厂。

如果选择了 Table Factory，它将创建圆桌或方桌（也是书写类型，圆形或方形）。如果选择该工厂，那么对于椅子工厂也是如此。

所以我的代码看起来像这样（某些部分可能不正确，这就是我问这个问题的原因）：

package pack1;
//abstract product
public abstract class Table {
    protected final String name;
    public Table(String name) { 
        this.name = name;
    }
}

package pack1;
//concrete product
public class SquareTable extends Table {
    public SquareTable(String name) { 
        super(name);
    }

}

package pack1;
//concrete product
public class RoundTable extends Table {
    public RoundTable(String name) { 
        super(name);
    }
}

package pack1;
//abstract product
public abstract class Chair {
     protected final String name;
        public Chair(String name) { 
            this.name = name;
        }
}

package pack1;
//concrete product
public class WoodenChair extends Chair {
    public WoodenChair(String name) { 
        super(name);
    }
}

package pack1;
//concrete product
public class MetalChair extends Chair {
    public MetalChair(String name) { 
        super(name);
    }

}

package pack1;
//Abstract Factory
public interface AbstractFurnitureFactory {
    public Table createTable(String type, String name);
    //not finished. How to use different create methods for different factories,
    //so it wouldn't require to use this method in concrete factories or
    //do I need 2 concrete factories for this to work?..
}

package pack1;
//concrete factory
public class TableFactory implements AbstractFurnitureFactory {
    public Table createTable(String type, String name){ 
    if(type.equals("square"))                       
    { 
        SquareTable sq_table=new SquareTable(name);
        return sq_table;
     }
     else
    {
        RoundTable rn_table=new RoundTable(name);
        return rn_table;
    }
}

}

package pack1;
//concrete factory
public class ChairFactory {
    public Chair createChair(String type, String name){ 
        if(type.equals("wood"))                       
        { 
            WoodenChair wd_chair=new WoodenChair(name);
            return wd_chair;
         }
         else
        {
            MetalChair mt_chair=new MetalChair(name);
            return mt_chair;
        }
    }
}

package pack1;
//client
public class FurnitureBuilder {
    public void buildTable(AbstractFurnitureFactory tf)
       {
          //Table table = tf.createTable();   
          //table.name = "New table";
          //not Finished. Java won't let me set arguments in createTable 
          //method for example. It gives error - 'The method 
          //createTable(String, String) in the type 
          //AbstractFurnitureFactory is not applicable for the arguments ()'
       }

}

package pack1;

public class Main {
    public static void main(String[] args)   
    {
        //FurnitureBuilder builder = new FurnitureBuilder();
        //AbstractFurnitureFactory TableFactory = null;
        //Not finished as some parts are missing.

    }
}

因此，如果有人能指出和/或纠正我做错了什么，我将非常感激。

Answer 1

我认为您混淆了哪些工厂应该从哪个抽象工厂继承。

更好的Factory 设计是让同一家工厂生产不同种类的Tables 或Chairs。这使得 AbstractFurnitureFactory 不需要。

例如：

  public interface TableFactory{

    Table createTable(String name);
  }


public class SquareTableFactory implements TableFactory{
    @Override
    Table createTable(String name){
          return new SquareTable(name);
    }
}

public class RoundTableFactory implements TableFactory{
    @Override
    Table createTable(String name){
          return new RoundTable(name);
    }
}

然后

public class FurnitureBuilder {
    private final TableFactory tf;
    private final ChairFactory cf;

    ...

   public void buildTable(String name){
      Table table = tf.createTable(name);
      ...
   }

}

希望这能让事情更清楚。