Question

我已经实现了一个基于mongodb记录的模型，我正在尝试编写表单来将数据（事件记录）存储到数据库中。

要存储的对象的片段是：

class eventSnippet extends StatefulSnippet with PaginatorSnippet[event] {

  var dispatch: DispatchIt = {
    case "editForm" => editForm _
  }

  var editingevent = event.createRecord


  def editForm(xhtml: NodeSeq): NodeSeq = {
        ("#editName" #> editingevent.title.toForm &
         "#editDescription" #> editingevent.description.toForm &
         "#editDT" #> editingevent.date_time.toForm &
         "#editCat" #> editingevent.category.toForm &
         "#editPrivacy" #> editingevent.privacy.toForm &
          "type=submit" #> SHtml.submit(?("Save"), () => save )).apply(xhtml)
  }

  def save = {
    editingevent.save
    redirectToHome
  }}

错误是：

class eventSnippet needs to be abstract, since:
[error] method page in trait Paginator of type => Seq[code.model.event] is not defined
[error] method count in trait Paginator of type => Long is not defined

当我将类更改为abstract时，它会编译，但我在浏览器上出错：

Message: java.lang.InstantiationException
sun.reflect.InstantiationExceptionConstructorAccessorImpl.newInstance(InstantiationExceptionConstructorAccessorImpl.java:30)
java.lang.reflect.Constructor.newInstance(Constructor.java:513)

我使用的是sbt 0.7.5和Scala 2.9.1。

Answer 1

Lift需要创建代码段的实例，因此它不能是抽象的。

我的代码段中没有任何内容需要分页。您只需删除with PaginatorSnippet[event]，而不要使类抽象。

如果确实需要分页，则必须提供page和count方法的实现。

class eventSnippet extends StatefulSnippet with PaginatorSnippet[event] {
  def page: Seq[event] = // return itemsPerPage events, starting at curPage*itemsPerPage

  def count: Long = // return total count of events.

  // ...
}

mongodb lift class Snippet需要抽象

1 个答案: