Scala example source code file (Pack200Task.scala)

This example Scala source code file (Pack200Task.scala) is included in my "Source Code Warehouse" project. The intent of this project is to help you more easily find Scala source code examples by using tags.

All credit for the original source code belongs to scala-lang.org; I'm just trying to make examples easier to find. (For my Scala work, see my Scala examples and tutorials.)

Scala tags/keywords

ant, boolean, file, int, jarfile, list, no, none, option, some, the

The Pack200Task.scala Scala example source code

/*                     __                                               *\
**     ________ ___   / /  ___     Scala Ant Tasks                      **
**    / __/ __// _ | / /  / _ |    (c) 2005-2013, LAMP/EPFL             **
**  __\ \/ /__/ __ |/ /__/ __ |    http://scala-lang.org/               **
** /____/\___/_/ |_/____/_/ | |                                         **
**                          |/                                          **
\*                                                                      */

package scala.tools.ant

import java.io.{BufferedOutputStream, File, FileInputStream,
       FileOutputStream, PipedInputStream, PipedOutputStream}
import java.util.jar.{JarFile, JarInputStream, JarOutputStream, Pack200}
import java.util.jar.Pack200.Packer._

import org.apache.tools.ant.{BuildException, DirectoryScanner}
import org.apache.tools.ant.types.FileSet

/** An [[http://ant.apache.org Ant]] task that applies the pack200 encoding
 *  to a JAR file.
 *
 *  - `destdir` (mandatory),
 *  - `dir` (defaults to project's basedir),
 *  - `effort` (default 9),
 *  - `keepFileOrder` (default `'''false'''`),
 *  - `keepModificationTime` (default `'''false'''`),
 *  - `repack` (default false),
 *  - `segmentLimit` (default `-1` for no limit),
 *  - `suffix` (default ".pack")
 *
 * @author  James Matlik
 */
class Pack200Task extends ScalaMatchingTask {

/*============================================================================*\
**                             Ant user-properties                            **
\*============================================================================*/

  var destdir: Option[File] = None
  var srcdir: Option[File] = None

  var effort = 9
  var keepFileOrder = false
  var keepModificationTime = false
  var repack = false
  var segmentLimit = -1

  var packFileSuffix = ".pack"


/*============================================================================*\
**                             Properties setters                             **
\*============================================================================*/

  def setDir(dir: File) {
    if (dir.exists && dir.isDirectory) srcdir = Some(dir)
    else buildError("Please specify a valid directory with Jar files for packing.")
  }

  /** A level from 0 (none) to 9 (max) of effort for applying Pack200 */
  def setEffort(x: Int) {
    if (effort < 10 && effort > -1) effort = x
    else buildError("The effort level must be a value from 0 to 9")
  }

  /** Set the flag to specify if file reordering should be performed. Reordering
    * is used to remove empty packages and improve pack200 optimization.
    * @param x
    *         `'''true'''` to retain file ordering.
    *         `'''false'''` to optimize directory structure (DEFAULT).  */
  def setKeepFileOrder(x: Boolean) { keepFileOrder = x }

  /** If false, a single modification time is used for all contained files */
  def setKeepModificationTime(x: Boolean) { keepModificationTime = x }

  /** A flag that tells the task to pack and then unpack the source JAR file
    * into another JAR file.  This resulting JAR file can then be signed,
    * packed again, compressed and distributed for securely distributed code.
    */
  def setRepack(r: Boolean) { repack = r }


  def setSegmentLimit(size: Int) { segmentLimit = size }

  /** Set the output directory */
  def setDestdir(file: File) {
    if (file != null && file.exists && file.isDirectory) destdir = Some(file)
    else buildError("The destination directory is invalid: " + file.getAbsolutePath)
  }

  def setSuffix(s: String) { packFileSuffix = s }

/*============================================================================*\
**                             Properties getters                             **
\*============================================================================*/

  /** Gets the list of individual JAR files for processing.
    * @return The list of JAR files */
  private def getFileList: List[File] = {
    var files: List[File] = Nil
    val fs = getImplicitFileSet
    val ds = fs.getDirectoryScanner(getProject())
    val dir = fs.getDir(getProject())
    for (filename <- ds.getIncludedFiles()
         if filename.toLowerCase.endsWith(".jar")) {
      val file = new File(dir, filename)
      if(files.exists(file.equals(_)) == false) files = file :: files
    }
    files.reverse
  }

/*============================================================================*\
**                       Compilation and support methods                      **
\*============================================================================*/

  private def makeJarOutputStream(file: File) =
    new JarOutputStream(makeOutputStream(file))

  private def makeOutputStream(file: File) =
    new BufferedOutputStream(new FileOutputStream(file))

/*============================================================================*\
**                           The big execute method                           **
\*============================================================================*/

  /** Performs the tool creation. */
  override def execute() = {
    // Audits
    val packDir = destdir.getOrElse(buildError("No output directory specified"))

    // Setup the inherited fileset for further processing
    fileset.setDir(srcdir.getOrElse(getProject.getBaseDir))

    val files = getFileList
    if (files.isEmpty) buildError("No JAR files were selected for packing.")

    // Setup the packer
    val packer = Pack200.newPacker
    val p = packer.properties
    p.put(EFFORT, effort.toString)
    p.put(SEGMENT_LIMIT, segmentLimit.toString)
    p.put(KEEP_FILE_ORDER, if(keepFileOrder) TRUE else FALSE)
    p.put(MODIFICATION_TIME, if(keepModificationTime) LATEST else KEEP)

    for (file <- files) {
      if (repack) {
        val repackedFile = new File(packDir, file.getName)
        if (file.lastModified > repackedFile.lastModified) {
          println("Repacking " + file.toString + " to " + repackedFile.toString)
          val tmpFile = new File(packDir, file.getName + ".tmp")
          val os = makeOutputStream(tmpFile)
          packer.pack(new JarFile(file), os)
          os.close()
          val jos = makeJarOutputStream(repackedFile)
          Pack200.newUnpacker.unpack(tmpFile, jos)
          jos.close()
          tmpFile.delete()
        }
      }
      else {
        val packFile: File = {
          val name = file.getName.substring(0, file.getName.lastIndexOf("."))
          new File(packDir, name + packFileSuffix)
        }
        if(file.lastModified > packFile.lastModified) {
          println("Packing " + file.toString + " to " + packFile.toString)
          val os = makeOutputStream(packFile)
          packer.pack(new JarFile(file), os)
        }
      }
    }
  }
}