Scala example source code file (Same.scala)

This example Scala source code file (Same.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

array, boolean, file, file, filenamemapper, io, mandatory, mapper, none, none, option, option, some, some, string

The Scala Same.scala source code

/*                     __                                               *\
**     ________ ___   / /  ___     Scala Ant Tasks                      **
**    / __/ __// _ | / /  / _ |    (c) 2005-2011, LAMP/EPFL             **
**  __\ \/ /__/ __ |/ /__/ __ |    http://scala-lang.org/               **
** /____/\___/_/ |_/____/_/ | |                                         **
**                          |/                                          **
\*                                                                      */


package scala.tools.ant

import java.io.{File, FileInputStream}

import org.apache.tools.ant.{BuildException, Project}
import org.apache.tools.ant.util.{FileNameMapper, IdentityMapper}

import org.apache.tools.ant.types.Mapper

/** <p>
 *    An Ant task that, for a set of files, tests them for byte-to-byte
 *    equality with one or more other files.
 *    This task supports the following parameters as attributes:
 *  </p>

 *  <li>dir
 *  <li>todir
 *  <li>resultproperty (a property to be set when all tested files pairs are equal, if not set, the task will fail instead),
 *  <li>failing (whether to stop if all files are not equal).
 *  <p>It also support the following nested elements:

 *  <li>mapper (a mapper from original files to test files).
 *  <p>This task itself defines a fileset that represents the set of original files.

 *
 * @author  Gilles Dubochet
 * @version 1.0 */
class Same extends ScalaMatchingTask {
/*============================================================================*\
**                             Ant user-properties                            **
\*============================================================================*/
  
  private var origin: Option[File] = None
  private var destination: Option[File] = None
  
  private var resultProperty: Option[String] = None
  private var failing: Boolean = false
  
  private var mapperElement: Option[Mapper] = None

/*============================================================================*\
**                             Properties setters                             **
\*============================================================================*/
  
  def setDir(input: File) =
    origin = Some(input)
  
  def setTodir(input: File) =
    destination = Some(input)
  
  def setResultproperty(input: String) =
    resultProperty = Some(input)
  
  def setFailondifferent(input: Boolean) =
    failing = input
  
  def createMapper(): Mapper =
    if (mapperElement.isEmpty) {
      val mapper = new Mapper(getProject)
      mapperElement = Some(mapper)
      mapper
    }
    else throw new BuildException("Cannot define more than one mapper", getLocation)
  
  def add(fileNameMapper: FileNameMapper) =
    createMapper().add(fileNameMapper)

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

  private def getMapper: FileNameMapper = mapperElement match {
    case None =>
      new IdentityMapper()
    case Some(me) =>
      me.getImplementation
  }

/*============================================================================*\
**                               Support methods                              **
\*============================================================================*/
  
  private var allEqualNow = true
  
  /** Tests if all mandatory attributes are set and valid. */
  private def validateAttributes() = {
    if (origin.isEmpty) sys.error("Mandatory attribute 'dir' is not set.")
    if (destination.isEmpty) sys.error("Mandatory attribute 'todir' is not set.")
  }
  
  private def reportDiff(f1: File, f2: File) = {
    allEqualNow = false
    log("File '" + f1 + "' is different from correspondant.")
  }
  
  private def reportMissing(f1: File) = {
    allEqualNow = false
    log("File '" + f1 + "' has no correspondant.")
  }

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

  override def execute() = {
    validateAttributes
    val mapper = getMapper
    allEqualNow = true
    val originNames: Array[String] = getDirectoryScanner(origin.get).getIncludedFiles
    val bufferSize = 1024
    val originBuffer = new Array[Byte](bufferSize)
    val destBuffer = new Array[Byte](bufferSize)
    for (
      originName: String <- originNames; 
      destName: String <- mapper.mapFileName(originName)
    ) {
      //println("originName="+originName)
      //println("destName  ="+destName)
      var equalNow = true
      val originFile = new File(origin.get, originName)
      val destFile = new File(destination.get, destName)
      if (originFile.canRead && destFile.canRead) {
        val originStream = new FileInputStream(originFile)
        val destStream = new FileInputStream(destFile)
        var originRemaining = originStream.read(originBuffer)
        var destRemaining = destStream.read(destBuffer)
        while (originRemaining > 0 && equalNow) {
          if (originRemaining == destRemaining)
            for (idx <- 0 until originRemaining)
              equalNow = equalNow && (originBuffer(idx) == destBuffer(idx))
          else
            equalNow = false
          originRemaining = originStream.read(originBuffer)
          destRemaining = destStream.read(destBuffer)
        }
        if (destRemaining > 0)
          equalNow = false
        if (!equalNow)
          reportDiff(originFile, destFile)
        originStream.close
        destStream.close
      }
      else reportMissing(originFile)
    }
    if (!allEqualNow)
      if (failing)
        sys.error("There were differences between '" + origin.get + "' and '" + destination.get + "'")
      else
        log("There were differences between '" + origin.get + "' and '" + destination.get + "'")
    else {
      if (!resultProperty.isEmpty)
        getProject.setProperty(resultProperty.get, "yes")
      log("All files in '" + origin.get + "' and '" + destination.get + "' are equal", Project.MSG_VERBOSE)
    }
  }

}