命令对象和hasmany

Question

我试图在提交表单时使用commandObject来验证我的数据。我可以验证commandObject中的hasMany关系吗？我的纪念日是这样的。

拖车简单classes蒙山的hasMany关系：

class Book{ 
    String nameBook 
} 

class Author{ 
    String nameAuthor 
    static hasMany = [books:Book]  
} 

简单commandObject与我想验证提交表单时的hasMany。

@grails.validation.Validateable 
class MyValidateCommand{ 

    String nameAuthor 
    static hasMany = [books:Book] 


    static constraints = { 
     nameAuthor nullable:false 
     books nullable:false 
    } 

} 

ps：我知道这个commandObject是错误的，它不会编译。但我可以做这样的事吗？

Answer 1

hasMany在GORM中用于关联域对象。在命令对象的情况下，这将是一个清晰的方法来为每个域不同的命令对象（例如：AuthorCommand和BookCommand）和命令对象将是这样的：

import org.apache.commons.collections.list.LazyList 
import org.apache.commons.collections.functors.InstantiateFactory 

//Dont need this annotation if command object 
//is in the same location as the controller 
//By default its validateable 
@grails.validation.Validateable 
class AuthorCommand{ 
    String nameAuthor 
    //static hasMany = [books:Book] 

    //Lazily initialized list for BookCommand 
    //which will be efficient based on the form submission. 
    List<BookCommand> books = 
      LazyList.decorate(new ArrayList(), 
           new InstantiateFactory(BookCommand.class)) 

    static constraints = { 
     nameAuthor nullable:false 
     books nullable:false 

     //Let BookCommand do its validation, 
     //although you can have a custom validator to do some 
     //validation here. 
    } 
} 

Answer 2

不知道为什么没有，你可以尝试像（正常休眠的hasMany声明）

class MyValidateCommand{ 

    String nameAuthor 
    Set<Book> books= new HashSet<Book>(); 


    static constraints = { 
     nameAuthor nullable:false 
     books nullable:false 
    } 

}