模型约束验证

发布于 2024-11-29 22:26:46 字数 454 浏览 2 评论 0原文

给定一个基于通用树（Java）的数据模型。假设

abstract class XModel {
  long id;
  XModel parent;
}

class ProjectModel extends XModel {
  String customer;
}

class FileModel extends XModel {
  String name;
}

class FolderModel extends XModel {
  String name;
  String attributes;
}

我的挑战是确保 FileModel 只在 FolderModels（或 ProjectModels）中使用，FolderModels 只在 ProjectModels 中使用。由于模型应该是可扩展的 - 是否有任何通用方法可以执行此约束验证（如 XML 模式），而无需在验证方法中对父子关系进行硬编码？

原文

Given a generic tree based (Java) data model. Let's say

abstract class XModel {
  long id;
  XModel parent;
}

class ProjectModel extends XModel {
  String customer;
}

class FileModel extends XModel {
  String name;
}

class FolderModel extends XModel {
  String name;
  String attributes;
}

My challenge is to make sure that FileModels are only used in FolderModels (or PrjectModels) and FolderModels are only used in ProjectModels.
Since the model should be extensible - is there any generic way to do this constraint validation (like XML Schema does) without hardcoding the parent-child-realtions in a validation method?

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空心↖ 2024-12-06 22:26:46

我不确定它有多大用处 - 取决于您如何创建树，但这可能有效：

abstract class XModel<T extends XModel> {
    long id;
    T parent;
}

class ProjectModel extends XModel { ... }

class FolderModel extends XModel<ProjectModel> { ... }

class FileModel extends XModel<FolderModel> { ... }

更新

要将验证逻辑与模型本身分开，您可以使用一些运行时验证器，例如 Hibernate 或 Spring 验证器。

I'm not sure how useful it would be - depends on how you create the tree, but this might work:

abstract class XModel<T extends XModel> {
    long id;
    T parent;
}

class ProjectModel extends XModel { ... }

class FolderModel extends XModel<ProjectModel> { ... }

class FileModel extends XModel<FolderModel> { ... }

UPDATE

To separate validation logic from model itself you could use some runtime validators like Hibernate or Spring validators.

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篱下浅笙歌 2024-12-06 22:26:46

我将使用描述限制的泛型和接口

  interface Model {

  }

  abstract class AbstractModel<P extends Model> implements Model {

    Long id;
    P    parent;
  }

  class ProjectModel extends AbstractModel implements HasFileModel,
      HasFolderModel {

  }

  interface HasFileModel extends Model {
  }

  static class FileModel extends AbstractModel<HasFileModel> {

  }

  interface HasFolderModel extends Model {

  }

  class FolderModel extends AbstractModel<HasFolderModel> implements
      HasFileModel {

  }

这样，子级仅将父级限制为接口而不是具体类型

I would use generics and interfaces that describe the restrictions

  interface Model {

  }

  abstract class AbstractModel<P extends Model> implements Model {

    Long id;
    P    parent;
  }

  class ProjectModel extends AbstractModel implements HasFileModel,
      HasFolderModel {

  }

  interface HasFileModel extends Model {
  }

  static class FileModel extends AbstractModel<HasFileModel> {

  }

  interface HasFolderModel extends Model {

  }

  class FolderModel extends AbstractModel<HasFolderModel> implements
      HasFileModel {

  }

This way the child only restricts the parent to an interface not a concrete type

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