Sure thing, it's quite long though :)
Just one thing, i added the following for it to compile (I want to
return List[User] not List[TagUser] : .map(_.user.obj.open_!)
So in all it looks like this
def getTopUsers(in: Int) :List[User] = {
TagUser.findAll(By(TagUser.tag, this.id), In(TagUser.user, User.id,
OrderBy(User.followers_count, Descending), MaxRows[User](in)))
.map(_.user.obj.open_!)
}
Exception occured while processing /
Message: java.lang.NullPointerException
net.liftweb.mapper.In$$anon$3.<init>(MetaMapper.scala:1206)
net.liftweb.mapper.In$.apply(MetaMapper.scala:1200)
scalableKvidr.model.Tag.getTopUsers(Tag.scala:38)
scalableKvidr.snippet.TagsSnippets$$anonfun$frontpageTags$1.apply
(TagsSnippets.scala:71)
scalableKvidr.snippet.TagsSnippets$$anonfun$frontpageTags$1.apply
(TagsSnippets.scala:68)
scala.List.flatMap(List.scala:1125)
scalableKvidr.snippet.TagsSnippets.frontpageTags(TagsSnippets.scala:
67)
sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
sun.reflect.NativeMethodAccessorImpl.invoke
(NativeMethodAccessorImpl.java:39)
sun.reflect.DelegatingMethodAccessorImpl.invoke
(DelegatingMethodAccessorImpl.java:25)
java.lang.reflect.Method.invoke(Method.java:597)
net.liftweb.util.ClassHelpers$$anonfun$net$liftweb$util$ClassHelpers$
$_invokeMethod$2$$anonfun$apply$7.apply(ClassHelpers.scala:352)
net.liftweb.util.ControlHelpers$class.tryo(ControlHelpers.scala:40)
net.liftweb.util.Helpers$.tryo(Helpers.scala:29)
net.liftweb.util.ControlHelpers$class.tryo(ControlHelpers.scala:55)
net.liftweb.util.Helpers$.tryo(Helpers.scala:29)
net.liftweb.util.ClassHelpers$$anonfun$net$liftweb$util$ClassHelpers$
$_invokeMethod$2.apply(ClassHelpers.scala:352)
net.liftweb.util.ClassHelpers$$anonfun$net$liftweb$util$ClassHelpers$
$_invokeMethod$2.apply(ClassHelpers.scala:352)
scala.Iterator$$anon$14.next(Iterator.scala:267)
scala.Iterator$class.find(Iterator.scala:462)
scala.Iterator$$anon$14.find(Iterator.scala:265)
net.liftweb.util.ClassHelpers$class.net$liftweb$util$ClassHelpers$
$_invokeMethod(ClassHelpers.scala:353)
net.liftweb.util.ClassHelpers$class.invokeMethod(ClassHelpers.scala:
285)
net.liftweb.util.Helpers$.invokeMethod(Helpers.scala:29)
net.liftweb.http.LiftSession$$anonfun$17$$anonfun$apply$33$$anonfun
$apply$36$$anonfun$apply$38.apply(LiftSession.scala:723)
net.liftweb.http.LiftSession$$anonfun$17$$anonfun$apply$33$$anonfun
$apply$36$$anonfun$apply$38.apply(LiftSession.scala:705)
net.liftweb.util.EmptyBox.openOr(Box.scala:372)
net.liftweb.http.LiftSession$$anonfun$17$$anonfun$apply$33$$anonfun
$apply$36.apply(LiftSession.scala:705)
net.liftweb.http.LiftSession$$anonfun$17$$anonfun$apply$33$$anonfun
$apply$36.apply(LiftSession.scala:705)
net.liftweb.util.EmptyBox.openOr(Box.scala:372)
net.liftweb.http.LiftSession$$anonfun$17$$anonfun$apply$33.apply
(LiftSession.scala:704)
net.liftweb.http.LiftSession$$anonfun$17$$anonfun$apply$33.apply
(LiftSession.scala:704)
net.liftweb.http.S$.doSnippet(S.scala:725)
net.liftweb.http.LiftSession$$anonfun$17.apply(LiftSession.scala:702)
net.liftweb.http.LiftSession$$anonfun$17.apply(LiftSession.scala:701)
net.liftweb.util.Full.map(Box.scala:330)
net.liftweb.http.LiftSession.net$liftweb$http$LiftSession$
$processSnippet(LiftSession.scala:701)
net.liftweb.http.LiftSession$$anonfun$_defaultLiftTagProcessing
$1.apply(LiftSession.scala:793)
net.liftweb.http.LiftSession$$anonfun$_defaultLiftTagProcessing
$1.apply(LiftSession.scala:777)
net.liftweb.util.NamedPF.apply(NamedPartialFunction.scala:30)
net.liftweb.util.NamedPF$.apply(NamedPartialFunction.scala:76)
net.liftweb.http.LiftSession$$anonfun$processSurroundAndInclude$1$
$anonfun$apply$49.apply(LiftSession.scala:808)
net.liftweb.http.LiftSession$$anonfun$processSurroundAndInclude$1$
$anonfun$apply$49.apply(LiftSession.scala:808)
net.liftweb.util.ThreadGlobal.doWith(ThreadGlobal.scala:65)
net.liftweb.http.S$.setVars(S.scala:623)
net.liftweb.http.LiftSession$$anonfun$processSurroundAndInclude
$1.apply(LiftSession.scala:808)
net.liftweb.http.LiftSession$$anonfun$processSurroundAndInclude
$1.apply(LiftSession.scala:805)
scala.Seq$class.flatMap(Seq.scala:294)
scala.xml.NodeSeq.flatMap(NodeSeq.scala:34)
net.liftweb.http.LiftSession.processSurroundAndInclude
(LiftSession.scala:804)
net.liftweb.http.LiftSession.net$liftweb$http$LiftSession$
$processSurroundElement(LiftSession.scala:948)
net.liftweb.http.LiftSession$$anonfun$_defaultLiftTagProcessing
$1.apply(LiftSession.scala:784)
net.liftweb.http.LiftSession$$anonfun$_defaultLiftTagProcessing
$1.apply(LiftSession.scala:777)
net.liftweb.util.NamedPF.apply(NamedPartialFunction.scala:30)
net.liftweb.util.NamedPF$.apply(NamedPartialFunction.scala:76)
net.liftweb.http.LiftSession$$anonfun$processSurroundAndInclude$1$
$anonfun$apply$49.apply(LiftSession.scala:808)
net.liftweb.http.LiftSession$$anonfun$processSurroundAndInclude$1$
$anonfun$apply$49.apply(LiftSession.scala:808)
net.liftweb.util.ThreadGlobal.doWith(ThreadGlobal.scala:65)
net.liftweb.http.S$.setVars(S.scala:623)
net.liftweb.http.LiftSession$$anonfun$processSurroundAndInclude
$1.apply(LiftSession.scala:808)
net.liftweb.http.LiftSession$$anonfun$processSurroundAndInclude
$1.apply(LiftSession.scala:805)
scala.Seq$class.flatMap(Seq.scala:294)
scala.xml.NodeSeq.flatMap(NodeSeq.scala:34)
net.liftweb.http.LiftSession.processSurroundAndInclude
(LiftSession.scala:804)
net.liftweb.http.LiftSession$$anonfun$8.apply(LiftSession.scala:462)
net.liftweb.http.LiftSession$$anonfun$8.apply(LiftSession.scala:462)
net.liftweb.util.Full.map(Box.scala:330)
net.liftweb.http.LiftSession.processRequest(LiftSession.scala:462)
net.liftweb.http.LiftServlet.net$liftweb$http$LiftServlet$
$dispatchStatefulRequest(LiftServlet.scala:244)
net.liftweb.http.LiftServlet$$anonfun$2.apply(LiftServlet.scala:176)
net.liftweb.http.LiftServlet$$anonfun$2.apply(LiftServlet.scala:176)
net.liftweb.http.S$.net$liftweb$http$S$$wrapQuery(S.scala:398)
net.liftweb.http.S$$anonfun$net$liftweb$http$S$$_nest2InnerInit$1$
$anonfun$apply$16.apply(S.scala:453)
net.liftweb.http.S$.net$liftweb$http$S$$doAround(S.scala:372)
net.liftweb.http.S$$anonfun$net$liftweb$http$S$$doAround$1.apply
(S.scala:373)
net.liftweb.mapper.DB$$anon$1.net$liftweb$mapper$DB$$anon$$doWith
(DB.scala:117)
net.liftweb.mapper.DB$$anon$1$$anonfun$net$liftweb$mapper$DB$$anon$
$doWith$1.apply(DB.scala:118)
net.liftweb.mapper.DB$$anon$1$$anonfun$net$liftweb$mapper$DB$$anon$
$doWith$1.apply(DB.scala:118)
net.liftweb.mapper.DB$.use(DB.scala:305)
net.liftweb.mapper.DB$$anon$1.net$liftweb$mapper$DB$$anon$$doWith
(DB.scala:118)
net.liftweb.mapper.DB$$anon$1.apply(DB.scala:124)
net.liftweb.http.S$.net$liftweb$http$S$$doAround(S.scala:373)
net.liftweb.http.S$$anonfun$net$liftweb$http$S$$_nest2InnerInit
$1.apply(S.scala:451)
net.liftweb.util.ThreadGlobal.doWith(ThreadGlobal.scala:65)
net.liftweb.http.S$.net$liftweb$http$S$$_nest2InnerInit(S.scala:450)
net.liftweb.http.S$$anonfun$net$liftweb$http$S$$_innerInit$1$$anonfun
$apply$19$$anonfun$apply$20$$anonfun$apply$21$$anonfun$apply$22$
$anonfun$apply$23$$anonfun$apply$24.apply(S.scala:471)
net.liftweb.util.ThreadGlobal.doWith(ThreadGlobal.scala:65)
net.liftweb.http.S$$anonfun$net$liftweb$http$S$$_innerInit$1$$anonfun
$apply$19$$anonfun$apply$20$$anonfun$apply$21$$anonfun$apply$22$
$anonfun$apply$23.apply(S.scala:470)
net.liftweb.util.ThreadGlobal.doWith(ThreadGlobal.scala:65)
net.liftweb.http.S$$anonfun$net$liftweb$http$S$$_innerInit$1$$anonfun
$apply$19$$anonfun$apply$20$$anonfun$apply$21$$anonfun$apply$22.apply
(S.scala:469)
net.liftweb.util.ThreadGlobal.doWith(ThreadGlobal.scala:65)
net.liftweb.http.S$$anonfun$net$liftweb$http$S$$_innerInit$1$$anonfun
$apply$19$$anonfun$apply$20$$anonfun$apply$21.apply(S.scala:468)
net.liftweb.util.ThreadGlobal.doWith(ThreadGlobal.scala:65)
net.liftweb.http.S$$anonfun$net$liftweb$http$S$$_innerInit$1$$anonfun
$apply$19$$anonfun$apply$20.apply(S.scala:467)
net.liftweb.util.ThreadGlobal.doWith(ThreadGlobal.scala:65)
net.liftweb.http.S$$anonfun$net$liftweb$http$S$$_innerInit$1$$anonfun
$apply$19.apply(S.scala:466)
net.liftweb.util.ThreadGlobal.doWith(ThreadGlobal.scala:65)
net.liftweb.http.S$$anonfun$net$liftweb$http$S$$_innerInit$1.apply
(S.scala:465)
net.liftweb.util.ThreadGlobal.doWith(ThreadGlobal.scala:65)
net.liftweb.http.S$.net$liftweb$http$S$$_innerInit(S.scala:464)
net.liftweb.http.S$$anonfun$_init$1$$anonfun$apply$27$$anonfun$apply
$28$$anonfun$apply$29$$anonfun$apply$30.apply(S.scala:495)
net.liftweb.util.ThreadGlobal.doWith(ThreadGlobal.scala:65)
net.liftweb.http.S$$anonfun$_init$1$$anonfun$apply$27$$anonfun$apply
$28$$anonfun$apply$29.apply(S.scala:494)
net.liftweb.http.RequestVarHandler$.apply(Vars.scala:191)
net.liftweb.http.S$$anonfun$_init$1$$anonfun$apply$27$$anonfun$apply
$28.apply(S.scala:493)
net.liftweb.util.ThreadGlobal.doWith(ThreadGlobal.scala:65)
net.liftweb.http.S$$anonfun$_init$1$$anonfun$apply$27.apply(S.scala:
492)
net.liftweb.util.ThreadGlobal.doWith(ThreadGlobal.scala:65)
net.liftweb.http.S$$anonfun$_init$1.apply(S.scala:491)
net.liftweb.util.ThreadGlobal.doWith(ThreadGlobal.scala:65)
net.liftweb.http.S$._init(S.scala:490)
net.liftweb.http.S$.init(S.scala:334)
net.liftweb.http.LiftServlet.doService(LiftServlet.scala:175)
net.liftweb.http.LiftServlet$$anonfun$doIt$1$1.apply
(LiftServlet.scala:104)
net.liftweb.http.LiftServlet$$anonfun$doIt$1$1.apply
(LiftServlet.scala:104)
net.liftweb.util.TimeHelpers$class.calcTime(TimeHelpers.scala:241)
net.liftweb.util.Helpers$.calcTime(Helpers.scala:29)
net.liftweb.util.TimeHelpers$class.logTime(TimeHelpers.scala:250)
net.liftweb.util.Helpers$.logTime(Helpers.scala:29)
net.liftweb.http.LiftServlet.doIt$1(LiftServlet.scala:103)
net.liftweb.http.LiftServlet.service(LiftServlet.scala:112)
net.liftweb.http.LiftFilterTrait$$anonfun$doFilter$1$$anonfun$apply
$22.apply(LiftServlet.scala:525)
net.liftweb.http.LiftFilterTrait$$anonfun$doFilter$1$$anonfun$apply
$22.apply(LiftServlet.scala:525)
net.liftweb.util.ThreadGlobal.doWith(ThreadGlobal.scala:65)
net.liftweb.http.URLRewriter$.doWith(Req.scala:390)
net.liftweb.http.LiftFilterTrait$$anonfun$doFilter$1.apply
(LiftServlet.scala:524)
net.liftweb.http.LiftFilterTrait$$anonfun$doFilter$1.apply
(LiftServlet.scala:518)
net.liftweb.http.RequestVarHandler$$anonfun$apply$3$$anonfun$apply$4$
$anonfun$apply$5$$anonfun$apply$6.apply(Vars.scala:197)
net.liftweb.util.ThreadGlobal.doWith(ThreadGlobal.scala:65)
net.liftweb.http.RequestVarHandler$$anonfun$apply$3$$anonfun$apply$4$
$anonfun$apply$5.apply(Vars.scala:196)
net.liftweb.util.ThreadGlobal.doWith(ThreadGlobal.scala:65)
net.liftweb.http.RequestVarHandler$$anonfun$apply$3$$anonfun$apply
$4.apply(Vars.scala:195)
net.liftweb.util.ThreadGlobal.doWith(ThreadGlobal.scala:65)
net.liftweb.http.RequestVarHandler$$anonfun$apply$3.apply(Vars.scala:
194)
net.liftweb.util.ThreadGlobal.doWith(ThreadGlobal.scala:65)
net.liftweb.http.RequestVarHandler$.apply(Vars.scala:193)
net.liftweb.http.LiftFilterTrait$class.doFilter(LiftServlet.scala:
517)
net.liftweb.http.LiftFilter.doFilter(LiftServlet.scala:536)
org.mortbay.jetty.servlet.ServletHandler$CachedChain.doFilter
(ServletHandler.java:1157)
org.mortbay.jetty.servlet.ServletHandler.handle(ServletHandler.java:
388)
org.mortbay.jetty.security.SecurityHandler.handle
(SecurityHandler.java:216)
org.mortbay.jetty.servlet.SessionHandler.handle(SessionHandler.java:
182)
org.mortbay.jetty.handler.ContextHandler.handle(ContextHandler.java:
765)
org.mortbay.jetty.webapp.WebAppContext.handle(WebAppContext.java:418)
org.mortbay.jetty.handler.ContextHandlerCollection.handle
(ContextHandlerCollection.java:230)
org.mortbay.jetty.handler.HandlerCollection.handle
(HandlerCollection.java:114)
org.mortbay.jetty.handler.HandlerWrapper.handle(HandlerWrapper.java:
152)
org.mortbay.jetty.Server.handle(Server.java:326)
org.mortbay.jetty.HttpConnection.handleRequest(HttpConnection.java:
542)
org.mortbay.jetty.HttpConnection$RequestHandler.headerComplete
(HttpConnection.java:923)
org.mortbay.jetty.HttpParser.parseNext(HttpParser.java:547)
org.mortbay.jetty.HttpParser.parseAvailable(HttpParser.java:212)
org.mortbay.jetty.HttpConnection.handle(HttpConnection.java:404)
org.mortbay.io.nio.SelectChannelEndPoint.run
(SelectChannelEndPoint.java:409)
org.mortbay.thread.QueuedThreadPool$PoolThread.run
(QueuedThreadPool.java:582)
On Jan 5, 8:34 pm, David Pollak <[email protected]> wrote:
> On Tue, Jan 5, 2010 at 11:33 AM, Mads Hartmann <[email protected]> wrote:
> > Thanks David,
> > It compiled just fine but I got a nullpointer exception for some
> > reason.
>
> Please post the stack trace.
>
>
>
>
>
> > For now I'll use the findAllByPreparedStatement method instead
> > so I can play along with my project.
>
> > Thanks for the help though :)
>
> > On Jan 5, 6:01 pm, David Pollak <[email protected]> wrote:
> > > Lift uses the SQL IN statement rather than joins. This has a negative
> > > impact for users of MySQL and Derby.
>
> > > Try:
>
> > > TagUser.findAll(By(TagUser.tag, this), In(TagUser.user, User.id,
> > > OrderBy(User.followers_count, Descending), MaxRows[User](10)))
>
> > > On Mon, Jan 4, 2010 at 11:10 PM, Mads Hartmann <[email protected]>
> > wrote:
> > > > My ultimate goal would be to only pull out the top x users. I'm
> > > > currently using the following code to achieve this:
>
> > > > TagUser.findAll(By(TagUser.tag, this.id)).map(_.user.obj.open_!)
> > > > .sort(_.followers_count.is > _.followers_count.is)
> > > > .take(x)
>
> > > > But im concerned that this creates an instance for each of the users
> > > > in tag tag even though i only need the top x.
>
> > > > Thanks for helping me out :)
>
> > > > On Jan 5, 1:47 am, David Pollak <[email protected]> wrote:
> > > > > On Mon, Jan 4, 2010 at 3:24 PM, Mads Hartmann <[email protected]>
> > wrote:
> > > > > > Hello, I'm having a problem and I'm sure it's an easy fix for
> > someone
> > > > > > with a bit more experience
>
> > > > > > I have 3 model classes: tag, user, tweet and a join class TagUser.
> > A
> > > > > > tag has a list of users.
>
> > > > > > If i want all of the users in a tag i use the following code (which
> > > > > > works):
>
> > > > > > def users = TagUser.findAll(By(TagUser.tag, this.id)).map
> > > > > > (_.user.obj.open_!)
>
> > > > > > my problem is that i can't figure out how to apply queryparams so i
> > > > > > don't pull out all of the users from the DB if i don't need em. I
> > was
> > > > > > thinking something like this (doesn't compile):
>
> > > > > > def getTopUsers(in: Int) :List[User] = {
> > > > > > TagUser.findAll(By(TagUser.tag, this.id),
> > > > > > OrderBy(User.followers_count, Descending),
> > > > > > MaxRows(in))
>
> > > > > There is an issue:
>
> > > > > OrderBy(User.xxxx, Descending) // illegal... you can only order by a
> > > > > TagUser.xxx field
>
> > > > > And a potential issue:
>
> > > > > MaxRows[TagUser](in) // sometimes the Type Inferencer doesn't get it
> > > > right.
>
> > > > > What's your ultimate goal?
>
> > > > > > }
>
> > > > > > I get the following error:
> > > > > > [ERROR] ... error: overloaded method value findAll with
> > alternatives
> > > > > > (net.liftweb.mapper.QueryParam[scalableKvidr.model.TagUser]*)List
> > > > > > [scalableKvidr.model.TagUser] <and> ()List
> > > > > > [scalableKvidr.model.TagUser] cannot be applied to
> > > > > > (net.liftweb.mapper.Cmp
> > > > > > [scalableKvidr.model.TagUser,Long],net.liftweb.mapper.OrderBy
> > > > > > [scalableKvidr.model.User,Int],net.liftweb.mapper.MaxRows[Nothing])
>
> > > > > > --
>
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> > > > > > [email protected]<liftweb%[email protected]
> > > > > > >
> > <liftweb%[email protected]<liftweb%252bunsubscr...@googlegroup
> > s.com>>
> > > > <liftweb%[email protected]<liftweb%252bunsubscr...@googlegroup
> > > > s.com>
> > <liftweb%252bunsubscr...@googlegroup s.com>>
> > > > > > .
> > > > > > For more options, visit this group at
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>
> > > > > --
> > > > > Lift, the simply functional web frameworkhttp://liftweb.net
> > > > > Beginning Scalahttp://www.apress.com/book/view/1430219890
> > > > > Follow me:http://twitter.com/dpp
> > > > > Surf the harmonics
>
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>
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> > s.com>>
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> > > > For more options, visit this group at
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>
> > > --
> > > Lift, the simply functional web frameworkhttp://liftweb.net
> > > Beginning Scalahttp://www.apress.com/book/view/1430219890
> > > Follow me:http://twitter.com/dpp
> > > Surf the harmonics
>
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>
> --
> Lift, the simply functional web frameworkhttp://liftweb.net
> Beginning Scalahttp://www.apress.com/book/view/1430219890
> Follow me:http://twitter.com/dpp
> Surf the harmonics
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