grails - 命令对象和 hasman

Question

我在提交表单时尝试使用 commandObject 来验证我的数据。我可以验证 commandObject 中的 hasMany 关系吗？我的场景是这样的。

两个简单的类，其中有很多关系:

class Book{
    String nameBook
}

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

简单的commandObject与hasMany，我想在提交表单时进行验证。

@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，它无法编译。但我可以做这样的事情吗？？？

Answer 1

GORM 中的

hasMany 用于 Domain 对象中的关联。对于命令对象，为每个域使用不同的命令对象(例如:AuthorCommand 和 BookCommand)将是一种清晰的方法，命令对象如下所示:

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.
    }
}