I have a working example of ManyToMany that adds roles to users. I would be happy to share my work but I have an aversion to github. I don't like it, It's a slower-than- molasses interface. It's buggy and user-hostile in my opinion. I'm looking for an alternative to make it public. Any suggestions would be appreciated.
Glenn... On Aug 25, 7:08 am, Naftoli Gugenheim <[email protected]> wrote: > "This" meaning the problem, or meaning ManyToMany? > It's pretty simple to use. You're mapper should extend ManyToMany, and you > should have a "field": > object m2m extends MappedManyToMany(.../*the two MetaMappers and foreign > keys, see the docs/source*/) > Then you can treat m2m as a Buffer, adding and deleting children. Call save > on the mapper or m2m to propogate the adding/deleting to the database, and > refresh to reset its contents to reflect the database. > However, as noted currently the children must be saved before they are added. > This is not the case for OneToMany, and for ManyToMany it should not be a > problem because usually the children exist independently of the > parent--that's why they can have 0 or 1 or more "parents." > > ------------------------------------- > > Randinn<[email protected]> wrote: > > Anyone have code showing this in action as it were? > > On Aug 6, 8:39 am, Naftoli Gugenheim <[email protected]> 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<[email protected]> 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 <[email protected]> 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<[email protected]> 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 <[email protected]> wrote: > > > > > Correction: ModelSnippet.load takes the actual Mapper instance, not the > > > > ModelView wrapper. > > > > > ------------------------------------- > > > > > Naftoli Gugenheim<[email protected]> 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<[email protected]> 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 <[email protected]> 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<[email protected]> 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 <[email protected]> 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 <[email protected]> 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 > > > > > > > <[email protected]>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<[email protected]> 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 > > ... > > read more » --~--~---------~--~----~------------~-------~--~----~ You received this message because you are subscribed to the Google Groups "Lift" group. To post to this group, send email to [email protected] To unsubscribe from this group, send email to [email protected] For more options, visit this group at http://groups.google.com/group/liftweb?hl=en -~----------~----~----~----~------~----~------~--~---
