I thought Naftoli's suggestion to make it a mixin so that it could be
added to MappedDates or MappedDateTimes was a reasonable one. Do you
think this just complicates things?
Peter
On Aug 7, 5:19 pm, David Pollak <feeder.of.the.be...@gmail.com> wrote:
> Why are you trying to make this a mixin? Why not just create a
> MappedTimestamp field?
>
> On Tue, Aug 4, 2009 at 2:27 PM, Peter Robinett <pe...@bubblefoundry.com>wrote:
>
>
>
>
>
> > Ahh, good idea. The compile errors all had to do with the the type
> > parameters. I don't know much about Scala's type system yet, so I was
> > defining the trait incorrectly based upon code I had copied and
> > pasted.
>
> > I'm now trying to have MappedTimestamp extend MappedField[Date, T]
> > instead and I am this much closer to getting it to work. Here are the
> > compile errors:
> > /Users/peter/Sites/liftstringprimary/src/main/scala/com/liftcode/model/
> > Cat.scala:38: error: illegal inheritance;
> > object ts inherits different type instances of trait MappedField:
> > net.liftweb.mapper.MappedField
> > [java.util.Date,net.liftweb.mapper.MappedDateTime[java.util.Date]] and
> > net.liftweb.mapper.MappedField[java.util.Date,com.liftcode.model.Cat]
> > object ts extends MappedDateTime(this) with MappedTimestamp
> > [MappedDateTime[Date]]
> > ^
> > /Users/peter/Sites/liftstringprimary/src/main/scala/com/liftcode/model/
> > Cat.scala:38: error: type arguments [net.liftweb.mapper.MappedDateTime
> > [java.util.Date]] do not conform to trait MappedTimestamp's type
> > parameter bounds [T <: net.liftweb.mapper.Mapper[T]]
> > object ts extends MappedDateTime(this) with MappedTimestamp
> > [MappedDateTime[Date]]
> > ^
> > two errors found
>
> > The relevant lines, I believe, are:
> > Cat.scala: object ts extends MappedDateTime(this) with MappedTimestamp
> > [MappedDateTime[Date]]
> > MappedTimstamp.scala: trait MappedTimestamp[T<:Mapper[T]] extends
> > MappedField[Date, T] {
>
> > And the code on GitHub:
> >http://github.com/pr1001/lift_1_1_sample/tree/master
>
> > As for all the overrides, looking at it again I see that I didn't need
> > to override all those build methods. The others are still needed to
> > have millisecond Longs where appropriate.
>
> > Peter
>
> > Peter
>
> > On Aug 4, 1:17 pm, Naftoli Gugenheim <naftoli...@gmail.com> wrote:
> > > Didn't look very closely, but if you extend MappedDate you lock yourself
> > out of MappedDatTime and vice versa. However both of them extend
> > MappedField[Date, T] which is a trait not a class, so if you extend that it
> > should be mixable in to both.
> > > What was the compile error?
> > > Aren't you writing a lot of functionality that is in MappedDate(Time)?
> > Define your mixin as a delta to MappedDate(Time); it should only have the
> > aspects that differentiate it.
>
> > > -------------------------------------
>
> > > Peter Robinett<pe...@bubblefoundry.com> wrote:
>
> > > Not at all, I just thought it would be hard to read. Here it is:
>
> > > Peter
>
> > > import _root_.java.sql.{ResultSet, Types}
> > > import _root_.java.util.Date
> > > import _root_.java.lang.reflect.Method
>
> > > import _root_.net.liftweb._
> > > import util._
> > > import Helpers._
> > > import http._
> > > import S._
> > > import js._
>
> > > import _root_.scala.xml.{NodeSeq}
>
> > > import net.liftweb.mapper.Mapper
> > > import net.liftweb.mapper.MappedDateTime
>
> > > trait MappedTimestamp[T<:Mapper[T]] extends MappedDateTime[Date] {
> > > this: T with MappedTimestamp[T] =>
>
> > > override def toLong: Long = is match {
> > > case null => 0L
> > > case d: Date => d.getTime
> > > }
>
> > > /**
> > > * Get the JDBC SQL Type for this field
> > > */
> > > override def targetSQLType = Types.BIGINT
>
> > > /**
> > > * Create an input field for the item
> > > */
> > > override def _toForm: Box[NodeSeq] =
> > > S.fmapFunc({s: List[String] => this.setFromAny(s)}){funcName =>
> > > Full(<input type='text' id={fieldId}
> > > name={funcName} lift:gc={funcName}
> > > value={is match {case null => "" case s => s}}/>)
> > > }
>
> > > override def jdbcFriendly(field : String) : Object = is match {
> > > case null => null
> > > case d => new _root_.java.sql.Date(d.getTime)
> > > }
>
> > > override def real_convertToJDBCFriendly(value: Date): Object = if
> > > (value == null) null else new _root_.java.lang.Long(value.getTime)
>
> > > override def buildSetActualValue(accessor: Method, v: AnyRef,
> > > columnName: String): (T, AnyRef) => Unit =
> > > (inst, v) => doField(inst, accessor, {case f: MappedTimestamp[T] =>
> > > f.st(toDate(v))})
>
> > > override def buildSetLongValue(accessor: Method, columnName:
> > > String): (T, Long, Boolean) => Unit =
> > > (inst, v, isNull) => doField(inst, accessor, {case f: MappedTimestamp
> > > [T] => f.st(if (isNull) Empty else Full(new Date(v)))})
>
> > > override def buildSetStringValue(accessor: Method, columnName:
> > > String): (T, String) => Unit =
> > > (inst, v) => doField(inst, accessor, {case f: MappedTimestamp[T] =>
> > > f.st(toDate(v))})
>
> > > override def buildSetDateValue(accessor: Method, columnName:
> > > String): (T, Date) => Unit =
> > > (inst, v) => doField(inst, accessor, {case f: MappedTimestamp[T] =>
> > > f.st(Full(v))})
>
> > > override def buildSetBooleanValue(accessor: Method, columnName:
> > > String): (T, Boolean, Boolean) => Unit =
> > > (inst, v, isNull) => doField(inst, accessor, {case f: MappedTimestamp
> > > [T] => f.st(Empty)})
>
> > > /**
> > > * Given the driver type, return the string required to create the
> > > column in the database
> > > */
> > > override def fieldCreatorString(dbType: DriverType, colName:
> > > String): String = colName + " " + dbType.longColumnType
>
> > > }
>
> > > On Aug 3, 6:59 pm, Naftoli Gugenheim <naftoli...@gmail.com> wrote:
>
> > > > Do you mind pasting it to the list?
>
> > > > -------------------------------------
>
> > > > Peter Robinett<pe...@bubblefoundry.com> wrote:
>
> > > > Naftoli, that's a great suggestion. I've taken a first, very bad stab
> > > > at such a trait:
> >http://github.com/pr1001/lift_1_1_sample/blob/ab945ba4960e6fc32c8f04c....
>
> > > > As the commit message says, the code is horrible and doesn't compile
> > > > because my Scala knowledge is quite limited. I'd appreciate advice on
> > > > how to correct my copy-and-paste job.
>
> > > > Peter
>
> > > > On Jul 30, 9:31 pm, Naftoli Gugenheim <naftoli...@gmail.com> wrote:
>
> > > > > Maybe I'm missing something that was said, but why can't
> > MappedTimestamp extend MappedDate(Time)? Or better yet, provide a trait to
> > mix in with either of the above?
>
> > > > > -------------------------------------
>
> > > > > Peter Robinett<pe...@bubblefoundry.com> wrote:
>
> > > > > Hi all,
>
> > > > > As some of you may have noticed, I have been playing around with
> > > > > timestamps[1] and mac addresses[2] in my models. I really like
> > > > > Mapper's specialized fields, both to make it easier for people to
> > read
> > > > > model definitions and to better ensure that only valid values are
> > used
> > > > > along all levels of the service, from the persistence to the
> > > > > presentation layers.
>
> > > > > So, I would like to propose an effort to develop more specialized
> > > > > fields, starting with MappedTimestamp and MappedMac. I talked to
> > David
> > > > > today and he is willing to provide some advice. Hopefully this will
> > > > > prove a useful way for me to improve my Scala knowledge and
> > contribute
> > > > > to Lift.
>
> > > > > Focusing just on the two mapped fields I mentioned, do you have any
> > > > > comments how that should be implemented? My thinking is that
> > > > > MappedTimestamp would be stored as a java.util.date and MappedMac as
> > > > > a String, converting both of them to Longs for the database in the
> > > > > interest of saving space.
>
> > > > > Are there any other mapped fields you'd like to see? I'll add that I
> > > > > think using the units compiler plugin[3] looks cool[4] but probably
> > > > > would be considered to create an unacceptable dependency.
>
> > > > > Peter Robinett
>
> > > > > [1]:
> >http://groups.google.com/group/liftweb/browse_thread/thread/b4bdedfb7...
> > > > > [2]:
> >http://groups.google.com/group/liftweb/browse_thread/thread/41650fc1e...
> > > > > [3]:
> >https://lampsvn.epfl.ch/trac/scala/browser/compiler-plugins/units/trunk
> > > > > [4]:
> >http://www.michaelnygard.com/blog/2009/05/units_of_measure_in_scala.html
>
> --
> Lift, the simply functional web frameworkhttp://liftweb.net
> Beginning Scalahttp://www.apress.com/book/view/1430219890
> Follow me:http://twitter.com/dpp
> Git some:http://github.com/dpp
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