Naftoli,
While your working on this issue, there seems to be another. Here's
what's happening:
If I make a coding mistake, and code User as follows:
class User extends MegaProtoUser[User] with ManyToMany[Long,Role]{
def getSingleton = User // what's the "meta" server
object roles
extends MappedManyToMany(UserRole, UserRole.user, UserRole.role,
Role)
}
instead of
class User extends MegaProtoUser[User] with ManyToMany[LongUser]{ ...
I don't get a compiler error (I'm using Eclipse with the Scala
plugin). Instead,
I get a stack overflow error and my IDE crashes.
Glenn...
On Aug 5, 3:39 pm, Naftoli Gugenheim <naftoli...@gmail.com> wrote:
> Oh, I think I know what the problem is. I think I should classify it as a bug.
> Since you're adding a Role that isn't saved yet, and ManyToMany tracks the
> children via the join table, it can't access the child. As a workaround save
> the Role before adding it, although the need to do so is against the idea of
> ManyToMany and OneToMany. I will see what I can do, G-d willing.
>
> -------------------------------------
>
> glenn<gl...@exmbly.com> wrote:
>
> Naftoli,
>
> Hate to do this to you, but I'm getting the following error using
> ManyToMany for Users to Roles:
>
> Message: java.lang.RuntimeException: Broken join
> scala.Predef$.error(Predef.scala:76)
> net.liftweb.mapper.ManyToMany$MappedManyToMany$$anonfun$children$1$
> $anonfun$apply$1.apply(ManyToMany.scala:54)
> net.liftweb.mapper.ManyToMany$MappedManyToMany$$anonfun$children$1$
> $anonfun$apply$1.apply(ManyToMany.scala:54)
> net.liftweb.util.EmptyBox.openOr(Box.scala:372)
> net.liftweb.mapper.ManyToMany$MappedManyToMany$$anonfun$children
> $1.apply(ManyToMany.scala:54)
> net.liftweb.mapper.ManyToMany$MappedManyToMany$$anonfun$children
> $1.apply(ManyToMany.scala:54)
> scala.List.map(List.scala:812)
> net.liftweb.mapper.ManyToMany$MappedManyToMany.children
> (ManyToMany.scala:54)
> net.liftweb.mapper.ManyToMany$MappedManyToMany.elements
> (ManyToMany.scala:96)
> scala.Seq$class.flatMap(Seq.scala:293)
> net.liftweb.mapper.ManyToMany$MappedManyToMany.flatMap
> (ManyToMany.scala:44)
>
> def edit(ns: NodeSeq): NodeSeq = {
> val theUser = view.entity
> val addRole = TheBindParam("insert", view.snippet.link("edit", ()
> => theUser.roles += new Role, Text(S?("Add Role"))))
>
> bind("user", ns,
> "firstname" -> text(theUser.firstName.is, theUser.firstName
> (_), ("size","20")),
> "lastname" -> text(theUser.lastName.is,theUser.lastName(_),
> ("size", "30")),
> "roles" -> theUser.roles.flatMap{role =>
> bind("role", ns,
> "name" -> role.name.toForm,
> "remove" -> SHtml.submit(S?("Remove"), ()=>
> theUser.roles -= role)
> )
> },
> addRole,
> "submit" -> SHtml.submit(S?("Save"), ()=>view.save)
> )
> }
>
> The offending code seems to be the line: "roles" ->
> theUser.roles.flatMap{....
> in the above bind method when I click on the addRole link.
>
> Here's my User class:
>
> class User extends MegaProtoUser[User] with ManyToMany[Long,User]{
> def getSingleton = User // what's the "meta" server
>
> object roles
> extends MappedManyToMany(UserRole, UserRole.user, UserRole.role,
> Role)
>
> }
>
> What am I doing wrong? You can see how difficult it is to slog through
> this code, let alone just
> trying to explain the problem so I can get help.
>
> On Aug 5, 9:57 am, Naftoli Gugenheim <naftoli...@gmail.com> wrote:
>
> > I'll try.
> > By the way, as per my correction, you can implement list the regular way
> > without ModelView, and just use ModelSnippet's load function in your edit
> > link or button, passing it the User instance.
>
> > -------------------------------------
>
> > glenn<gl...@exmbly.com> wrote:
>
> > Naftoli,
>
> > I fixed my code per your comments and now I can edit and remove users
> > from a list, as long as I populate the list with
> > ModelView instances, as you said. As for the docs, this step was not
> > clear to me at all. I just assumed that the list was
> > just populated with User entities and the view in the ModelSnippet was
> > instantiated with the selected User on each request.
>
> > It sounds like your plate is pretty full, so I won't expect much, but
> > sometime soon, could you provide an example, or improved
> > docs, for using TableEditor and its related ItemsList trait.
>
> > Thanks for all.
>
> > Glenn...
>
> > On Aug 5, 9:18 am, Naftoli Gugenheim <naftoli...@gmail.com> wrote:
>
> > > Correction: ModelSnippet.load takes the actual Mapper instance, not the
> > > ModelView wrapper.
>
> > > -------------------------------------
>
> > > Naftoli Gugenheim<naftoli...@gmail.com> wrote:
>
> > > To answer your immediate question, the listing should not refer to the
> > > snippet's view but new ModelView instances for each entity. Then
> > > editAction is shorthand for the snippet's link method with a callback to
> > > call load on the ModelView. To set the snippet's view's entity, either
> > > call load on the snippet with the other ModelView, or call load on the
> > > other ModelView (or just set its entity directly).
> > > As far as documentation, please tell me what scaladocs need what
> > > clarification. Thanks.
>
> > > -------------------------------------
>
> > > glenn<gl...@exmbly.com> wrote:
>
> > > Naftoli,
>
> > > Functional programming systems are notoriously difficult to document.
> > > The only way to really know what's going on is to meticulously trace
> > > through the source. But that requires
> > > time-consuming trial and error coding. So, without clear examples
> > > demonstrating exactly what you have in mind, I and others in the same
> > > boat, could spend days and still not
> > > get it right.
>
> > > For example, I tried this:
>
> > > var theUser:User = null
> > > val view = new ModelView(theUser, this)
>
> > > def list(ns: NodeSeq): NodeSeq = User.currentUser.map({user =>
> > > User.findAll.flatMap({u =>
> > > bind("user", chooseTemplate("user", "entry", ns),
> > > "firstname" -> Text(u.firstName.is),
> > > "lastname" -> Text(u.lastName.is),
> > > "email" -> Text(u.email.is),
> > > "roles" -> u.roles.map(_.name.toString).mkString(",
> > > "),
> > > view.editAction,
> > > view.removeAction
> > > )
> > > })
> > > }) openOr Text("You're not logged in")
>
> > > and, I get a null value exception when I try to remove a user in the
> > > list. Simply using
> > > val view = new ModelView(new User, this), doesn't work either,
> > > although I don't get an
> > > exception. Now, where should I be calling load in all of this?
>
> > > Glenn...
>
> > > On Aug 3, 6:22 pm, Naftoli Gugenheim <naftoli...@gmail.com> wrote:
>
> > > > Your snippet should extend ModelSnippet (which extends StatefulSnippet).
> > > > Then write:
> > > > val view = new ModelView(new User, this) {}
> > > > Calling load on another ModelView that references the snippet will load
> > > > its entity into that view val. It has a number of methods of possible
> > > > interest, like save which checks validity.
> > > > Also see Util.
> > > > Are you seeing the scaladocs?
>
> > > > -------------------------------------
>
> > > > glenn<gl...@exmbly.com> wrote:
>
> > > > Just to add to what I just wrote, I don't see how your ModelView can
> > > > be applied to
> > > > User, which already extends a class, MegaProtoUser. Maybe I'm not
> > > > comprehending this correctly.
>
> > > > Glenn...
>
> > > > On Aug 3, 3:48 pm, glenn <gl...@exmbly.com> wrote:
>
> > > > > Naftoli,
>
> > > > > Liked your OneToMany article, but not sure how the new
> > > > > ModelView and ModelSnippet code can be applied to ManyToMany.
> > > > > Can you provide a sample?
>
> > > > > Glenn...
>
> > > > > On Aug 2, 1:21 pm, Naftoli Gugenheim <naftoli...@gmail.com> wrote:
>
> > > > > > I put an article on the wiki about OneToMany
> > > > > > --http://wiki.github.com/dpp/liftweb/how-to-work-with-one-to-many-relat...
> > > > > > .
>
> > > > > > On Sun, Aug 2, 2009 at 11:20 AM, Naftoli Gugenheim
> > > > > > <naftoli...@gmail.com>wrote:
>
> > > > > > > Glad to hear. Also see mapper.view.ItemsList (anyone have a
> > > > > > > better name?),
> > > > > > > which is used byTableEditor. It's a similar idea without
> > > > > > > relationships.
> > > > > > > Should MappedOne/ManyToMany be based on ItemsList?
> > > > > > > Also should I take Mapped out of those names? After all, they're
> > > > > > > not
> > > > > > > MappedFields and they don't correspond to a table column.
>
> > > > > > > -------------------------------------
> > > > > > > Magnus Alvestad<magnus.alves...@gmail.com> wrote:
>
> > > > > > > This work that you've done in Mapper fits in very well with
> > > > > > > something
> > > > > > > I've been planning to do. In a Java project some time ago we
> > > > > > > implemented a 'change engine'. We were loading big pension
> > > > > > > agreements,
> > > > > > > manipulating them in a web interface and finally saving them back
> > > > > > > to
> > > > > > > the database. While the user was working on the agreement, we
> > > > > > > generated a list of changes, containing enough information to
> > > > > > > replay
> > > > > > > or unroll the change. We could use this to implement undo and some
> > > > > > > semi-intelligent merging when two users were trying to commit
> > > > > > > changes
> > > > > > > to the same agreement. We also let the user review his changes
> > > > > > > before
> > > > > > > saving, and we indicated changed fields visually. We were even
> > > > > > > thinking of implementing some kind of macro or replay
> > > > > > > functionality,
> > > > > > > but never got that far.
>
> > > > > > > I've been trying to implement something similar as a lift
> > > > > > > component,
> > > > > > > but with the old relationship handling it wasn't practical. With
> > > > > > > your
> > > > > > > changes it should be. Thanks!
>
> > > > > > > -Magnus
>
> > > > > > > On Jul 27, 9:57 pm, Naftoli Gugenheim <naftoli...@gmail.com>
> > > > > > > wrote:
> > > > > > > > I committed some code last night, which can help building
> > > > > > > > mapper-based
> > > > > > > view snippets, with G-d's help. It includes the following classes:
> > > > > > > > (1-2) net.liftweb.mapper.OneToMany, ManyToMany: Gives a more
> > > > > > > object-oriented approach to managing related entites. You can
> > > > > > > manage the
> > > > > > > many side of a 1-n and n-n as a mutable collection of children,
> > > > > > > and the
> > > > > > > parent of a child can be set directly, instead of via its id. And
> > > > > > > the
> > > > > > > children are not saved to the database when you add them until
> > > > > > > you call save
> > > > > > > on it or its parent, nor deleted when you remove tem until you
> > > > > > > call
> > > > > > > delete_!, which is very helpful when you
>
> ...
>
> read more »
--~--~---------~--~----~------------~-------~--~----~
You received this message because you are subscribed to the Google Groups
"Lift" group.
To post to this group, send email to liftweb@googlegroups.com
To unsubscribe from this group, send email to
liftweb+unsubscr...@googlegroups.com
For more options, visit this group at
http://groups.google.com/group/liftweb?hl=en
-~----------~----~----~----~------~----~------~--~---
