tech.mlsql.common.ScalaReflect.scala Maven / Gradle / Ivy

Go to download
Show more of this group Show more artifacts with this name
Show all versions of delta-plus_2.11 Show documentation
A library based on delta for Spark and [MLSQL](http://www.mlsql.tech).
The newest version!
package tech.mlsql.common

import scala.reflect.ClassTag
import scala.reflect.runtime.{universe => ru}

/**
  * 2019-05-01 WilliamZhu([email protected])
  */

class ScalaReflect {}

object ScalaReflect {
  private def mirror = {
    ru.runtimeMirror(getClass.getClassLoader)
  }

  def fromInstance[T: ClassTag](obj: T) = {
    val x = mirror.reflect[T](obj)
    new ScalaMethodReflect(x)
  }

  def fromObject[T: ru.TypeTag]() = {
    new ScalaModuleReflect(ru.typeOf[T].typeSymbol.companion.asModule)
  }

  def fromObjectStr(str: String) = {
    val module = mirror.staticModule(str)
    new ScalaModuleReflect(module)
  }

  //def getClass[T: ru.TypeTag](obj: T) = ru.typeTag[T].tpe.typeSymbol.asClass


}

class ScalaModuleReflect(x: ru.ModuleSymbol) {

  private var methodName: Option[ru.MethodSymbol] = None
  private var fieldName: Option[ru.TermSymbol] = None

  def method(name: String) = {
    methodName = Option(x.typeSignature.member(ru.TermName(name)).asMethod)
    this
  }

  def field(name: String) = {
    fieldName = Option(x.typeSignature.member(ru.TermName(name)).asTerm)
    this
  }

  private def mirror = {
    ru.runtimeMirror(getClass.getClassLoader)
  }

  def invoke(objs: Any*) = {

    if (methodName.isDefined) {
      val instance = mirror.reflectModule(x).instance
      mirror.reflect(instance).reflectMethod(methodName.get.asMethod)(objs)
    } else if (fieldName.isDefined) {
      val instance = mirror.reflectModule(x).instance
      val fieldMirror = mirror.reflect(instance).reflectField(fieldName.get)
      if (objs.size > 0) {
        fieldMirror.set(objs.toSeq(0))
      }
      fieldMirror.get

    } else {
      throw new IllegalArgumentException("Can not invoke `invoke` without call method or field function")
    }

  }
}

class ScalaMethodReflect(x: ru.InstanceMirror) {

  private var methodName: Option[ru.MethodSymbol] = None
  private var fieldName: Option[ru.TermSymbol] = None

  def method(name: String) = {
    methodName = Option(x.symbol.typeSignature.member(ru.TermName(name)).asMethod)
    this
  }

  def field(name: String) = {
    fieldName = Option(x.symbol.typeSignature.member(ru.TermName(name)).asTerm)
    this
  }

  def invoke(objs: Any*) = {

    if (methodName.isDefined) {
      x.reflectMethod(methodName.get.asMethod)(objs: _*)
    } else if (fieldName.isDefined) {
      val fieldMirror = x.reflectField(fieldName.get)
      if (objs.size > 0) {
        fieldMirror.set(objs.toSeq(0))
      }
      fieldMirror.get

    } else {
      throw new IllegalArgumentException("Can not invoke `invoke` without call method or field function")
    }


  }
}