GORM关系中的抽象类 [英] Abstract Classes in GORM Relationships

问题描述

Grails GORM不会将抽象域类持久化到数据库，从而导致多态关系中断。例如：

pre $ 抽象类用户{
字符串电子邮件
字符串密码
静态约束= {
email（空白：假，可空：false，电子邮件：真）
密码（空白：假，密码：真）
}

static hasMany = [会员：GroupMembership]
}

类RegularEmployee延伸用户{}

类经理扩展用户{
工作组managed_Group
}

类文档{
字符串名称
字符串描述
文件大小
字符串fileExtension
用户所有者
创建日期时间
日期lastModifiedTime
DocumentData myData
boolean isCheckedOut
enum灵敏度{LOW，MEDIUM，HIGH}
def documentImportance = Sensitivity.LOW

static constraints = {
名称（可空：假，空：假）
描述（可空：false，空：假）
fileSize（可空：false）
fileExtension（可为空）：
所有者（可空值：false）
myData（可空值：false）
}
}


原因

引起：org.hibernate.MappingException：
表文档引用一个未映射的类：User
... 25更多2009-11-11 23:52:58,933 [main]错误mortbay.log - 嵌套在org.springframework.beans.factory .BeanCreationException：创建名为'messageSource'的bean时出错：bean
的初始化失败;嵌套的异常是
org.springframework.beans.factory.BeanCreationException：错误
创建名为'transactionManager'的bean：在设置bean属性'sessionFactory'时无法将引用
解析为bean'sessionFactory';
嵌套异常是
org.springframework.beans.factory.BeanCreationException：错误
创建名为'sessionFactory'的bean：调用init方法
失败;嵌套异常是org.hibernate.MappingException：表格文档中的
关联指的是一个未映射的类：User：
org.hibernate.MappingException：来自表文档
的关联指的是一个未映射的类：用户

但在这种情况下，我希望允许任何用户拥有文档的多态效应，同时强制每个用户该系统适合其中一个定义的角色。因此，用户不应该被直接实例化并被抽象化。

我不想在非抽象User类中使用enum作为角色，因为我希望能够为不同角色添加额外属性，在某些情况下可能没有意义（我不希望有一个单一的用户角色设置为RegularEmployee，以某种方式获取非空的managedGroup）。

这是一个bug在Grails中？我错过了什么吗？

解决方案

您可能希望查看Shiro，Nimble（使用Shiro）和/或Spring Security插件的域模型。他们创建一个具体的用户域和一个具体的角色域。特别是Shiro为多对多的映射创建了一个UserRole域。

然后在你的Role域上，你可以添加你想要的任何属性。如果需要，您可以创建一个单独的域以允许任意属性，如下所示：

 类角色{
 //一些属性
 static hasMany = [roleProperties：RoleProperty，...] 
} 
 $ b $ class RoleProperty {
字符串名称
字符串值
静态belongsTo = [角色：作用] 
} 
  

我认为你不会尽管可以在当前的域映射中获得您想要的内容。

Grails GORM does not persist abstract domain classes to the database, causing a break in polymorphic relationships. For example:

abstract class User {
    String email
    String password
    static constraints = {
        email(blank:false, nullable:false,email:true)
        password(blank:false, password:true)
    }

    static hasMany = [membership:GroupMembership]
}

class RegularEmployee extends User {}

class Manager extends User {
    Workgroup managedGroup
}

class Document {
    String name
    String description
    int fileSize
    String fileExtension
    User owner
    Date creationTime
    Date lastModifiedTime
    DocumentData myData
    boolean isCheckedOut
    enum Sensitivity {LOW,MEDIUM,HIGH}
    def documentImportance = Sensitivity.LOW

    static constraints = {
        name(nullable:false, blank:false)
        description(nullable:false, blank:false)
        fileSize(nullable:false)
        fileExtension(nullable:false)
        owner(nullable:false)
        myData(nullable:false)
    }
}

causes

Caused by: org.hibernate.MappingException: An association from the table document refers to an unmapped class: User ... 25 more 2009-11-11 23:52:58,933 [main] ERROR mortbay.log - Nested in org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'messageSource': Initialization of bean failed; nested exception is org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'transactionManager': Cannot resolve reference to bean 'sessionFactory' while setting bean property 'sessionFactory'; nested exception is org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'sessionFactory': Invocation of init method failed; nested exception is org.hibernate.MappingException: An association from the table document refers to an unmapped class: User: org.hibernate.MappingException: An association from the table document refers to an unmapped class: User

But in this scenario, I want the polymorphic effects of allowing any user to own a document, while forcing every user of the system to fit into one of the defined roles. Hence, User should not be directly instantiated and is made abstract.

I don't want to use an enum for roles in a non-abstract User class, because I want to be able to add extra properties to the different roles, which may not make sense in certain contexts (I don't wanna have a single User with role set to RegularEmployee that somehow gets a not null managedGroup).

Is this a bug in Grails? Am I missing something?

解决方案

You might like to view the domain models for the Shiro, Nimble (uses Shiro), and/or Spring Security plugins. They create a concrete User domain and a concrete Role domain. Shiro in particular creates a UserRole domain for the many-to-many mapping.

Then on your Role domain, you can add whatever properties you want. If necessary, you can create a separate domain to allow for arbitrary properties like so:

class Role {
    //some properties
    static hasMany = [roleProperties:RoleProperty, ...]
}

class RoleProperty {
    String name
    String value
    static belongsTo = [role:Role]
}

I don't think you'll get what you're looking for in your current domain mapping though.

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