java - Defining and referencing a generic type bound in Play template signature -

java - Defining and referencing a generic type bound in Play template signature -

i have number of sorted maps, keyed time , value of some type. illustration, consider have 3 maps (in java):

sortedmap<offsetdatetime, foo> foo; sortedmap<offsetdatetime, boo> bar; sortedmap<offsetdatetime, baz> baz;

i wish write generic play template accepts map, , renderer function, , outputs each pair.

within template, can define local function next signature:

@rendertrace[t <: any](trace: immutablesortedmap[offsetdatetime, option[t]], renderer: (t) => html) = {

however, utilize function in multiple templates, not want define locally. rather, had hoped define own template (in rendertrace.scala.html).

unfortunately, don't seem able able specify type construction [t <: any] in template signature.

how can define re-usable, generically typed function?

to flesh out @ashalynd's suggestion, template compiler doesn't appear smart plenty handle type parameters. can utilize underscore type parameter (only when don't care type is), isn't 1 of cases.

a play (now called twirl) template function produces result of type play.twirl.api.html (or play.api.templates.html play 2.2). templates compiler needs worked around, define helper bundle containing function:

package viewhelpers import play.twirl.api.html // play.api.templates.html 2.2 object viewextension { def rendertrace[t <: any](trace: immutablesortedmap[offsetdatetime, option[t]], renderer: (t) => html): html = ... }

the implementation of rendertrace might not nice in view template, @ to the lowest degree can work now.

then in view:

@(someparams: ....) @import viewhelpers.viewextension @{viewextension.rendertrace(...)}

java scala templates generics playframework-2.2