Scala example source code file (GenAndroid.scala)

This example Scala source code file (GenAndroid.scala) is included in the DevDaily.com "Java Source Code Warehouse" project. The intent of this project is to help you "Learn Java by Example" ^TM.

Java - Scala tags/keywords

androidcreatorclass, androidparcelableinterface, androidparcelableinterface, bytecodegenerator, bytecodegenerator, call_method, creator, creator, jobjecttype, nosymbol, nosymbol, static, store_field, symbol

The Scala GenAndroid.scala source code

/* NSC -- new Scala compiler
 * Copyright 2005-2011 LAMP/EPFL
 * @author  Stephane Micheloud
 */


package scala.tools.nsc
package backend.jvm

import ch.epfl.lamp.fjbg._
import symtab.Flags

trait GenAndroid {
  self: GenJVM =>

  import global._
  import icodes._
  import opcodes._

  /** From the reference documentation of the Android SDK:
   *  The `Parcelable` interface identifies classes whose instances can be
   *  written to and restored from a `Parcel`. Classes implementing the
   *  `Parcelable` interface must also have a static field called `CREATOR`,
   *  which is an object implementing the `Parcelable.Creator` interface.
   */
  private val fieldName = "CREATOR"

  private lazy val AndroidParcelableInterface =
    try definitions.getClass("android.os.Parcelable")
    catch { case _: FatalError => NoSymbol }

  private lazy val AndroidCreatorClass =
    if (AndroidParcelableInterface == NoSymbol) NoSymbol
    else definitions.getClass("android.os.Parcelable$Creator")

  def isAndroidParcelableClass(sym: Symbol) =
    (AndroidParcelableInterface != NoSymbol) &&
    (sym.info.parents contains AndroidParcelableInterface.tpe)

  def addCreatorCode(codegen: BytecodeGenerator, block: BasicBlock) {
    import codegen._
    val fieldSymbol = clasz.symbol.newValue(NoPosition, newTermName(fieldName))
                        .setFlag(Flags.STATIC | Flags.FINAL)
                        .setInfo(AndroidCreatorClass.tpe)
    val methodSymbol = definitions.getMember(clasz.symbol.companionModule, fieldName)
    clasz addField new IField(fieldSymbol)
    block emit CALL_METHOD(methodSymbol, Static(false))
    block emit STORE_FIELD(fieldSymbol, true)
  }

  def legacyAddCreatorCode(codegen: BytecodeGenerator, clinit: JExtendedCode) {
    import codegen._
    val creatorType = javaType(AndroidCreatorClass)
    jclass.addNewField(PublicStaticFinal,
                       fieldName,
                       creatorType)
    val moduleName = javaName(clasz.symbol)+"$"
    clinit.emitGETSTATIC(moduleName,
                         nme.MODULE_INSTANCE_FIELD.toString,
                         new JObjectType(moduleName))
    clinit.emitINVOKEVIRTUAL(moduleName, fieldName,
                             new JMethodType(creatorType, Array()))
    clinit.emitPUTSTATIC(jclass.getName(), fieldName, creatorType)
  }

}