家具和测试的OOAD设计

Question

这个问题是在一次采访中提出的。

家具可以由一种或多种材料制成。家具种类繁多，如椅子、桌子、沙发等。

家具测试取决于材料和家具类型。很少有测试是可选的，耐火的，WithStands100KgWeight的等等。

在OOAD中设计这个。该设计应遵循开放关闭原则，并应乐观，以便在未来如果增加新家具，它不应该需要更多的代码改变。

最初建议

class Furniture{
List<Material> materials;
boolean supportsTest(Test test);
}

class Chair extends Furniture{
boolean supportsTest(Test test){
// check material and based on type return true/false
}

面试官说，家具是家具，不应该说它支持不支持这个测试。有其他解决办法吗？谢谢。

Answer 1

根据你的描述和面试官的评论，这就是我所想到的：

// An interface so that it's separate from Furniture class
interface FurnitureTest {
   bool IsSupportedBy(Furniture furniture);
}

// Sample test, can add as many as you like
class FireResistable : FurnitureTest {
   public bool IsSupportedBy(Furniture furniture) {
       return furniture.Type.Name == ! "Mirror" && /* just to use the Type property */
              !furniture.HasMaterial(x => x == "Wood");
   }
}

///
/// Other class definitions.
///

// Open to extension
class Chair : Furniture { /* additional properties */ }
class Table : Furniture { /* additional properties */ }

// Closed to modification
class Furniture {
   public FurnitureType FurnitureType { get; private set; }
   private IList<Material> materials;

   public Furniture(FurnitureType type, IList<Material> materials) {
      this.materials = materials;
   }

   public bool HasMaterial(string materialName) {
      return materials.Any(x => x.Name == materialName);
   }
}

class FurnitureType {
   public string Name { get; set; }
   // ...other properties
}

class Material {
   public string Name { get; set; }
   // other properties..
}