Scala example source code file (AbstractFileClassLoader.scala)

This example Scala source code file (AbstractFileClassLoader.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

abstractfile, abstractfile, abstractfileclassloader, array, array, classloader, classloader, classnotfoundexception, jclass, net, network, scalaclassloader, string, string

The Scala AbstractFileClassLoader.scala source code

/* NSC -- new Scala compiler
 * Copyright 2005-2011 LAMP/EPFL
 */

package scala.tools.nsc
package interpreter

import scala.tools.nsc.io.{ File, AbstractFile }
import util.ScalaClassLoader
import java.net.URL

/**
 * A class loader that loads files from a {@link scala.tools.nsc.io.AbstractFile}.
 * 
 * @author Lex Spoon
 */
class AbstractFileClassLoader(root: AbstractFile, parent: ClassLoader)
    extends ClassLoader(parent)
    with ScalaClassLoader
{
  protected def classNameToPath(name: String): String =
    if (name endsWith ".class") name
    else name.replace('.', '/') + ".class"

  protected def findAbstractFile(name: String): AbstractFile = {
    var file: AbstractFile = root
    val pathParts          = classNameToPath(name) split '/'

    for (dirPart <- pathParts.init) {
      file = file.lookupName(dirPart, true)
      if (file == null)
        return null
    }
      
    file.lookupName(pathParts.last, false) match {
      case null   => null
      case file   => file
    }
  }

  override def getResourceAsStream(name: String) = findAbstractFile(name) match {
    case null => super.getResourceAsStream(name)
    case file => file.input
  }  
  override def classBytes(name: String): Array[Byte] = findAbstractFile(name) match {
    case null => super.classBytes(name)
    case file => file.toByteArray
  }
  override def findClass(name: String): JClass = {
    val bytes = classBytes(name)
    if (bytes.isEmpty) throw new ClassNotFoundException(name)
    else defineClass(name, bytes, 0, bytes.length)
  }
  // Don't know how to construct an URL for something which exists only in memory
  // override def getResource(name: String): URL = findAbstractFile(name) match {
  //   case null   => super.getResource(name)
  //   case file   => new URL(...)
  // }
}