我正在使用Swagger来注释我的API，在我们的API中，我们非常依赖enumeratum。如果我什么都不做，那么昂首阔步就不会认出它而只是称之为object。
例如，我有这个代码有效：
sealed trait Mode extends EnumEntry
object Mode extends Enum[Mode] {
override def values = findValues
case object Initial extends Mode
case object Delta extends Mode
}
@ApiModel
case class Foobar(
@ApiModelProperty(dataType = "string", allowedValues = "Initial,Delta")
mode: Mode
)
但是，我想避免重复这些值，因为我的某些类型比这个例子有更多;我不想手动保持同步。
问题是@ApiModel想要一个常量参考，所以我不能做像reference = Mode.values.mkString(",")这样的事情。
我确实尝试过宏天堂的宏，通常所以我可以写：
@EnumeratumApiModel(Mode)
sealed trait Mode extends EnumEntry
object Mode extends Enum[Mode] {
override def values = findValues
case object Initial extends Mode
case object Delta extends Mode
}
...但它不起作用，因为宏传递无法访问Mode对象。
我有什么解决方案可以避免重复注释中的值？
这包括代码，因此对于评论来说太大了。
我试过，这是行不通的，因为@ApiModel注释想要一个String常量作为值（而不是对常量的引用）
这段代码编译对我来说很好（注意你应该如何避免显式指定类型）：
import io.swagger.annotations._
import enumeratum._
@ApiModel(reference = Mode.reference)
sealed trait Mode extends EnumEntry
object Mode extends Enum[Mode] {
final val reference = "enum(Initial,Delta)" // this works!
//final val reference: String = "enum(Initial,Delta)" // surprisingly this doesn't!
override def values = findValues
case object Initial extends Mode
case object Delta extends Mode
}
所以似乎有足够的另一个宏来生成这样的reference字符串，我假设你已经有一个（或者你可以创建一个基于EnumMacros.findValuesImpl的代码）。
更新
以下是POC的一些代码，它实际上可以正常工作。首先，您从以下macro annotation开始：
import scala.language.experimental.macros
import scala.annotation.{StaticAnnotation, compileTimeOnly}
import scala.reflect.macros.whitebox.Context
import scala.collection.immutable._
@compileTimeOnly("enable macro to expand macro annotations")
class SwaggerEnumContainer extends StaticAnnotation {
def macroTransform(annottees: Any*) = macro SwaggerEnumMacros.genListString
}
@compileTimeOnly("enable macro to expand macro annotations")
class SwaggerEnumValue(val readOnly: Boolean = false, val required: Boolean = false) extends StaticAnnotation {
def macroTransform(annottees: Any*) = macro SwaggerEnumMacros.genParamAnnotation
}
class SwaggerEnumMacros(val c: Context) {
import c.universe._
def genListString(annottees: c.Expr[Any]*): c.Expr[Any] = {
val result = annottees.map(_.tree).toList match {
case (xxx@q"object $name extends ..$parents { ..$body }") :: Nil =>
val enclosingObject = xxx.asInstanceOf[ModuleDef]
val q"${tq"$pname[..$ptargs]"}(...$pargss)" = parents.head
val enumTraitIdent = ptargs.head.asInstanceOf[Ident]
val subclassSymbols: List[TermName] = enclosingObject.impl.body.foldLeft(List.empty[TermName])((list, innerTree) => {
innerTree match {
case innerObj: ModuleDefApi =>
val innerParentIdent = innerObj.impl.parents.head.asInstanceOf[Ident]
if (enumTraitIdent.name.equals(innerParentIdent.name))
innerObj.name :: list
else
list
case _ => list
}
})
val reference = subclassSymbols.map(n => n.encodedName.toString).mkString(",")
q"""
object $name extends ..$parents {
final val allowableValues = $reference
..$body
}
"""
}
c.Expr[Any](result)
}
def genParamAnnotation(annottees: c.Expr[Any]*): c.Expr[Any] = {
val annotationParams: AnnotationParams = extractAnnotationParameters(c.prefix.tree)
val baseSwaggerAnnot =
q""" new ApiModelProperty(
dataType = "string",
allowableValues = Mode.allowableValues
) """.asInstanceOf[Apply] // why I have to force cast?
val swaggerAnnot: c.universe.Apply = annotationParams.addArgsTo(baseSwaggerAnnot)
annottees.map(_.tree).toList match {
// field definition
case List(param: ValDef) => c.Expr[Any](decorateValDef(param, swaggerAnnot))
// field in a case class = constructor param
case (param: ValDef) :: (rest@(_ :: _)) => decorateConstructorVal(param, rest, swaggerAnnot)
case _ => c.abort(c.enclosingPosition, "SwaggerEnumValue is expected to be used for value definitions")
}
}
def decorateValDef(valDef: ValDef, swaggerAnnot: Apply): ValDef = {
val q"$mods val $name: $tpt = $rhs" = valDef
val newMods: Modifiers = mods.mapAnnotations(al => swaggerAnnot :: al)
q"$newMods val $name: $tpt = $rhs"
}
def decorateConstructorVal(annottee: c.universe.ValDef, expandees: List[Tree], swaggerAnnot: Apply): c.Expr[Any] = {
val q"$_ val $tgtName: $_ = $_" = annottee
val outputs = expandees.map {
case q"$mods class $tpname[..$tparams] $ctorMods(...$paramss) extends { ..$earlydefns } with ..$parents { $self => ..$stats }" => {
// paramss is a 2d array so map inside map
val newParams: List[List[ValDef]] = paramss.map(_.map({
case valDef: ValDef if valDef.name == tgtName => decorateValDef(valDef, swaggerAnnot)
case otherParam => otherParam
}))
q"$mods class $tpname[..$tparams] $ctorMods(...$newParams) extends { ..$earlydefns } with ..$parents { $self => ..$stats }"
}
case otherTree => otherTree
}
c.Expr[Any](Block(outputs, Literal(Constant(()))))
}
case class AnnotationParams(readOnly: Boolean, required: Boolean) {
def customCopy(name: String, value: Any) = {
name match {
case "readOnly" => copy(readOnly = value.asInstanceOf[Boolean])
case "required" => copy(required = value.asInstanceOf[Boolean])
case _ => c.abort(c.enclosingPosition, s"Unknown parameter '$name'")
}
}
def addArgsTo(annot: Apply): Apply = {
val additionalArgs: List[AssignOrNamedArg] = List(
AssignOrNamedArg(q"readOnly", q"$readOnly"),
AssignOrNamedArg(q"required", q"$required")
)
Apply(annot.fun, annot.args ++ additionalArgs)
}
}
private def extractAnnotationParameters(tree: Tree): AnnotationParams = tree match {
case ap: Apply =>
val argNames = Array("readOnly", "required")
val defaults = AnnotationParams(readOnly = false, required = false)
ap.args.zipWithIndex.foldLeft(defaults)((acc, argAndIndex) => argAndIndex match {
case (lit: Literal, index: Int) => acc.customCopy(argNames(index), c.eval(c.Expr[Any](lit)))
case (namedArg: AssignOrNamedArg, _: Int) =>
val q"$name = $lit" = namedArg
acc.customCopy(name.asInstanceOf[Ident].name.toString, c.eval(c.Expr[Any](lit)))
case _ => c.abort(c.enclosingPosition, "Failed to parse annotation params: " + argAndIndex)
})
}
}
然后你可以这样做：
sealed trait Mode extends EnumEntry
@SwaggerEnumContainer
object Mode extends Enum[Mode] {
override def values = findValues
case object Initial extends Mode
case object Delta extends Mode
}
@ApiModel
case class Foobar(@ApiModelProperty(dataType = "string", allowableValues = Mode.allowableValues) mode: Mode)
或者你可以这样做，我觉得有点清洁
@ApiModel
case class Foobar2(
@SwaggerEnumValue mode: Mode,
@SwaggerEnumValue(true) mode2: Mode,
@SwaggerEnumValue(required = true) mode3: Mode,
i: Int, s: String = "abc") {
@SwaggerEnumValue
val modeField: Mode = Mode.Delta
}
请注意，这仍然只是一个POC。已知的缺陷包括：
@SwaggerEnumContainer无法处理一些假的allowableValues已经定义了一些假值（这可能对IDE更好）@SwaggerEnumValue仅支持原始@ApiModelProperty中可用范围的两个属性