Scala example source code file (Comparator.scala)

This example Scala source code file (Comparator.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, array, comparator, comparing, file, file, fileinputstream, fileinputstream, io, logger, none, path, path, pathfinder, some

The Scala Comparator.scala source code

import sbt._
import java.io.{File, FileInputStream}

// Based on scala.tools.ant.Same
object Comparator {

    private def getMappedPath(path: Path, baseDirectory: Path): Path = {
      Path.fromString(baseDirectory, path.relativePath)
    }


    def compare(origin: Path, dest: Path, filter: Path => PathFinder, log: Logger): Option[String] = {
      log.info("Comparing the contents of "+origin.absolutePath+ " with "+dest.absolutePath)
      var allEqualNow = true

      def reportDiff(f1: File, f2: File) = {
        allEqualNow = false
        log.error("File '" + f1 + "' is different from correspondant.")
      }

      def reportMissing(f1: File) = {
        allEqualNow = false
        log.error("File '" + f1 + "' has no correspondant.")
      }



      val originPaths = filter(origin).get
      
      val bufferSize = 1024
      val originBuffer = new Array[Byte](bufferSize)
      val destBuffer = new Array[Byte](bufferSize)
      
      for (originPath <- originPaths.filter(! _.isDirectory)){
        log.debug("origin :" + originPath.absolutePath)
        val destPath = getMappedPath(originPath, dest)
        log.debug("dest   :" + destPath.absolutePath)
        var equalNow = true      
        val originFile = originPath.asFile
        val destFile = destPath.asFile

        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) None else Some("There were differences between "+origin.absolutePath+ " and "+ dest.absolutePath)
    }


}