added solution for completionstage

VL03-04-01/build.gradle

@@ -0,0 +1,26 @@
+apply plugin: 'java'
+
+apply plugin: 'eclipse'
+// Run 'gradlew eclipse' for the eclipse project
+
+apply plugin: 'idea'
+// Run 'gradle idea' for the IntelliJ idea project (no longer necessary in idea 13)
+
+// Netbeans: See http://plugins.netbeans.org/plugin/44510/gradle-support
+
+
+apply plugin:'application'
+// Rung 'gradle run' to execute main program
+
+mainClassName = "de.dhbw.parprog.DirSize"
+
+
+repositories {
+	mavenCentral()
+}
+
+dependencies {
+	implementation 'commons-lang:commons-lang:2.6'
+	testImplementation 'junit:junit:4.11'
+	testImplementation 'org.easytesting:fest-assert:1.4'
+}

VL03-04-01/gradle/wrapper/gradle-wrapper.properties

@@ -0,0 +1,6 @@
+#Sun Mar 15 22:48:49 CET 2015
+distributionBase=GRADLE_USER_HOME
+distributionPath=wrapper/dists
+zipStoreBase=GRADLE_USER_HOME
+zipStorePath=wrapper/dists
+distributionUrl=https\://services.gradle.org/distributions/gradle-8.4-bin.zip

VL03-04-01/gradlew

@@ -0,0 +1,164 @@
+#!/usr/bin/env bash
+
+##############################################################################
+##
+##  Gradle start up script for UN*X
+##
+##############################################################################
+
+# Add default JVM options here. You can also use JAVA_OPTS and GRADLE_OPTS to pass JVM options to this script.
+DEFAULT_JVM_OPTS=""
+
+APP_NAME="Gradle"
+APP_BASE_NAME=`basename "$0"`
+
+# Use the maximum available, or set MAX_FD != -1 to use that value.
+MAX_FD="maximum"
+
+warn ( ) {
+    echo "$*"
+}
+
+die ( ) {
+    echo
+    echo "$*"
+    echo
+    exit 1
+}
+
+# OS specific support (must be 'true' or 'false').
+cygwin=false
+msys=false
+darwin=false
+case "`uname`" in
+  CYGWIN* )
+    cygwin=true
+    ;;
+  Darwin* )
+    darwin=true
+    ;;
+  MINGW* )
+    msys=true
+    ;;
+esac
+
+# For Cygwin, ensure paths are in UNIX format before anything is touched.
+if $cygwin ; then
+    [ -n "$JAVA_HOME" ] && JAVA_HOME=`cygpath --unix "$JAVA_HOME"`
+fi
+
+# Attempt to set APP_HOME
+# Resolve links: $0 may be a link
+PRG="$0"
+# Need this for relative symlinks.
+while [ -h "$PRG" ] ; do
+    ls=`ls -ld "$PRG"`
+    link=`expr "$ls" : '.*-> \(.*\)$'`
+    if expr "$link" : '/.*' > /dev/null; then
+        PRG="$link"
+    else
+        PRG=`dirname "$PRG"`"/$link"
+    fi
+done
+SAVED="`pwd`"
+cd "`dirname \"$PRG\"`/" >&-
+APP_HOME="`pwd -P`"
+cd "$SAVED" >&-
+
+CLASSPATH=$APP_HOME/gradle/wrapper/gradle-wrapper.jar
+
+# Determine the Java command to use to start the JVM.
+if [ -n "$JAVA_HOME" ] ; then
+    if [ -x "$JAVA_HOME/jre/sh/java" ] ; then
+        # IBM's JDK on AIX uses strange locations for the executables
+        JAVACMD="$JAVA_HOME/jre/sh/java"
+    else
+        JAVACMD="$JAVA_HOME/bin/java"
+    fi
+    if [ ! -x "$JAVACMD" ] ; then
+        die "ERROR: JAVA_HOME is set to an invalid directory: $JAVA_HOME
+
+Please set the JAVA_HOME variable in your environment to match the
+location of your Java installation."
+    fi
+else
+    JAVACMD="java"
+    which java >/dev/null 2>&1 || die "ERROR: JAVA_HOME is not set and no 'java' command could be found in your PATH.
+
+Please set the JAVA_HOME variable in your environment to match the
+location of your Java installation."
+fi
+
+# Increase the maximum file descriptors if we can.
+if [ "$cygwin" = "false" -a "$darwin" = "false" ] ; then
+    MAX_FD_LIMIT=`ulimit -H -n`
+    if [ $? -eq 0 ] ; then
+        if [ "$MAX_FD" = "maximum" -o "$MAX_FD" = "max" ] ; then
+            MAX_FD="$MAX_FD_LIMIT"
+        fi
+        ulimit -n $MAX_FD
+        if [ $? -ne 0 ] ; then
+            warn "Could not set maximum file descriptor limit: $MAX_FD"
+        fi
+    else
+        warn "Could not query maximum file descriptor limit: $MAX_FD_LIMIT"
+    fi
+fi
+
+# For Darwin, add options to specify how the application appears in the dock
+if $darwin; then
+    GRADLE_OPTS="$GRADLE_OPTS \"-Xdock:name=$APP_NAME\" \"-Xdock:icon=$APP_HOME/media/gradle.icns\""
+fi
+
+# For Cygwin, switch paths to Windows format before running java
+if $cygwin ; then
+    APP_HOME=`cygpath --path --mixed "$APP_HOME"`
+    CLASSPATH=`cygpath --path --mixed "$CLASSPATH"`
+
+    # We build the pattern for arguments to be converted via cygpath
+    ROOTDIRSRAW=`find -L / -maxdepth 1 -mindepth 1 -type d 2>/dev/null`
+    SEP=""
+    for dir in $ROOTDIRSRAW ; do
+        ROOTDIRS="$ROOTDIRS$SEP$dir"
+        SEP="|"
+    done
+    OURCYGPATTERN="(^($ROOTDIRS))"
+    # Add a user-defined pattern to the cygpath arguments
+    if [ "$GRADLE_CYGPATTERN" != "" ] ; then
+        OURCYGPATTERN="$OURCYGPATTERN|($GRADLE_CYGPATTERN)"
+    fi
+    # Now convert the arguments - kludge to limit ourselves to /bin/sh
+    i=0
+    for arg in "$@" ; do
+        CHECK=`echo "$arg"|egrep -c "$OURCYGPATTERN" -`
+        CHECK2=`echo "$arg"|egrep -c "^-"`                                 ### Determine if an option
+
+        if [ $CHECK -ne 0 ] && [ $CHECK2 -eq 0 ] ; then                    ### Added a condition
+            eval `echo args$i`=`cygpath --path --ignore --mixed "$arg"`
+        else
+            eval `echo args$i`="\"$arg\""
+        fi
+        i=$((i+1))
+    done
+    case $i in
+        (0) set -- ;;
+        (1) set -- "$args0" ;;
+        (2) set -- "$args0" "$args1" ;;
+        (3) set -- "$args0" "$args1" "$args2" ;;
+        (4) set -- "$args0" "$args1" "$args2" "$args3" ;;
+        (5) set -- "$args0" "$args1" "$args2" "$args3" "$args4" ;;
+        (6) set -- "$args0" "$args1" "$args2" "$args3" "$args4" "$args5" ;;
+        (7) set -- "$args0" "$args1" "$args2" "$args3" "$args4" "$args5" "$args6" ;;
+        (8) set -- "$args0" "$args1" "$args2" "$args3" "$args4" "$args5" "$args6" "$args7" ;;
+        (9) set -- "$args0" "$args1" "$args2" "$args3" "$args4" "$args5" "$args6" "$args7" "$args8" ;;
+    esac
+fi
+
+# Split up the JVM_OPTS And GRADLE_OPTS values into an array, following the shell quoting and substitution rules
+function splitJvmOpts() {
+    JVM_OPTS=("$@")
+}
+eval splitJvmOpts $DEFAULT_JVM_OPTS $JAVA_OPTS $GRADLE_OPTS
+JVM_OPTS[${#JVM_OPTS[*]}]="-Dorg.gradle.appname=$APP_BASE_NAME"
+
+exec "$JAVACMD" "${JVM_OPTS[@]}" -classpath "$CLASSPATH" org.gradle.wrapper.GradleWrapperMain "$@"

VL03-04-01/gradlew.bat

@@ -0,0 +1,90 @@
+@if "%DEBUG%" == "" @echo off
+@rem ##########################################################################
+@rem
+@rem  Gradle startup script for Windows
+@rem
+@rem ##########################################################################
+
+@rem Set local scope for the variables with windows NT shell
+if "%OS%"=="Windows_NT" setlocal
+
+@rem Add default JVM options here. You can also use JAVA_OPTS and GRADLE_OPTS to pass JVM options to this script.
+set DEFAULT_JVM_OPTS=
+
+set DIRNAME=%~dp0
+if "%DIRNAME%" == "" set DIRNAME=.
+set APP_BASE_NAME=%~n0
+set APP_HOME=%DIRNAME%
+
+@rem Find java.exe
+if defined JAVA_HOME goto findJavaFromJavaHome
+
+set JAVA_EXE=java.exe
+%JAVA_EXE% -version >NUL 2>&1
+if "%ERRORLEVEL%" == "0" goto init
+
+echo.
+echo ERROR: JAVA_HOME is not set and no 'java' command could be found in your PATH.
+echo.
+echo Please set the JAVA_HOME variable in your environment to match the
+echo location of your Java installation.
+
+goto fail
+
+:findJavaFromJavaHome
+set JAVA_HOME=%JAVA_HOME:"=%
+set JAVA_EXE=%JAVA_HOME%/bin/java.exe
+
+if exist "%JAVA_EXE%" goto init
+
+echo.
+echo ERROR: JAVA_HOME is set to an invalid directory: %JAVA_HOME%
+echo.
+echo Please set the JAVA_HOME variable in your environment to match the
+echo location of your Java installation.
+
+goto fail
+
+:init
+@rem Get command-line arguments, handling Windowz variants
+
+if not "%OS%" == "Windows_NT" goto win9xME_args
+if "%@eval[2+2]" == "4" goto 4NT_args
+
+:win9xME_args
+@rem Slurp the command line arguments.
+set CMD_LINE_ARGS=
+set _SKIP=2
+
+:win9xME_args_slurp
+if "x%~1" == "x" goto execute
+
+set CMD_LINE_ARGS=%*
+goto execute
+
+:4NT_args
+@rem Get arguments from the 4NT Shell from JP Software
+set CMD_LINE_ARGS=%$
+
+:execute
+@rem Setup the command line
+
+set CLASSPATH=%APP_HOME%\gradle\wrapper\gradle-wrapper.jar
+
+@rem Execute Gradle
+"%JAVA_EXE%" %DEFAULT_JVM_OPTS% %JAVA_OPTS% %GRADLE_OPTS% "-Dorg.gradle.appname=%APP_BASE_NAME%" -classpath "%CLASSPATH%" org.gradle.wrapper.GradleWrapperMain %CMD_LINE_ARGS%
+
+:end
+@rem End local scope for the variables with windows NT shell
+if "%ERRORLEVEL%"=="0" goto mainEnd
+
+:fail
+rem Set variable GRADLE_EXIT_CONSOLE if you need the _script_ return code instead of
+rem the _cmd.exe /c_ return code!
+if  not "" == "%GRADLE_EXIT_CONSOLE%" exit 1
+exit /b 1
+
+:mainEnd
+if "%OS%"=="Windows_NT" endlocal
+
+:omega

VL03-04-01/src/main/java/de/dhbw/parprog/DirSize.java

@@ -0,0 +1,93 @@
+package de.dhbw.parprog;
+
+import java.io.File;
+import java.util.ArrayList;
+import java.util.List;
+import java.util.concurrent.CompletableFuture;
+import java.util.stream.Collectors;
+
+/**
+ * Class to get the directory size and file count using Completion Stages.
+ */
+public class DirSize {
+
+  /**
+   * This is a helper method to convert a list of future to a future of list using
+   * the same type.
+   * 
+   * @param <T>     The type of list and future.
+   * @param futures The list of futures to be converted.
+   * @return The future of list.
+   */
+  public static <T> CompletableFuture<List<T>> sequence(List<CompletableFuture<T>> futures) {
+    CompletableFuture<Void> allDoneFuture = CompletableFuture
+        .allOf(futures.toArray(new CompletableFuture[futures.size()]));
+    return allDoneFuture.thenApply(v -> futures.stream()
+        .map(future -> future.join())
+        .collect(Collectors.<T>toList()));
+  }
+
+  /**
+   * Method to get stats of a directory.
+   * 
+   * @param dir The directory to get the stats of.
+   * @return A future with stats of the directory.
+   */
+  public CompletableFuture<DirStats> dirStats(File dir) {
+    CompletableFuture<List<CompletableFuture<DirStats>>> folder = CompletableFuture.supplyAsync(() -> {
+      DirStats folderStats = new DirStats();
+      List<CompletableFuture<DirStats>> listDirStats = new ArrayList<>();
+      File[] contents = dir.listFiles();
+
+      if (contents != null) {
+        for (File file : contents) {
+          if (file.isDirectory()) {
+            if (!file.getName().equals(".")) {
+              listDirStats.add(dirStats(file));
+            }
+          } else {
+            folderStats.fileCount++;
+            folderStats.totalSize += file.length();
+          }
+        }
+      }
+
+      listDirStats.add(CompletableFuture.completedFuture(folderStats));
+      return listDirStats;
+    });
+
+    CompletableFuture<List<DirStats>> flattened = folder.thenCompose(future -> {
+      return sequence(future);
+    });
+
+    return flattened.thenApply(list -> {
+      DirStats sum = new DirStats();
+
+      for (DirStats stats : list) {
+        sum.fileCount += stats.fileCount;
+        sum.totalSize += stats.totalSize;
+      }
+
+      return sum;
+    });
+  }
+
+  public static void main(String[] args) throws Exception {
+
+    if (args.length < 1) {
+      System.out.println("Benötigter Parameter: Startverzeichnis");
+      System.exit(1);
+    }
+
+    File startDir = new File(args[0]);
+
+    if (!startDir.isDirectory()) {
+      System.out.println("Dies ist kein Verzeichnis!");
+      System.exit(1);
+    }
+
+    DirSize test = new DirSize();
+    DirStats result = test.dirStats(startDir).get();
+    System.out.println(result.fileCount + " Dateien, " + result.totalSize + " Bytes.");
+  }
+}

VL03-04-01/src/main/java/de/dhbw/parprog/DirStats.java

@@ -0,0 +1,44 @@
+package de.dhbw.parprog;
+
+/**
+ * Class representing stats for a directory.
+ */
+public class DirStats {
+
+  /**
+   * The count of files.
+   */
+	int fileCount;
+
+  /**
+   * The total size of all files.
+   */
+	long totalSize;
+	
+  /**
+   * Creates a new instance for stats.
+   */
+	public DirStats() {
+		fileCount = 0;
+		totalSize = 0;
+	}
+
+  /**
+   * Creates a new instance for stats with values.
+   * @param fileCount The count of files.
+   * @param totalSize The size of all files.
+   */
+	public DirStats(int fileCount, long totalSize) {
+		this.fileCount = fileCount;
+		this.totalSize = totalSize;
+	}
+	
+  /**
+   * Gets the string representation of the stats.
+   * @return The string with stats of directory.
+   */
+	@Override
+	public String toString() {
+		return "DirStats(fileCount=" + fileCount + ", totalSize=" + totalSize + ")";
+	}
+}

VL03-04-01/src/test/java/de/dhbw/parprog/DirStatTests.java

@@ -0,0 +1,22 @@
+package de.dhbw.parprog;
+
+import static org.fest.assertions.Assertions.assertThat;
+
+import java.io.File;
+import org.junit.Test;
+import org.junit.runner.RunWith;
+import org.junit.runners.JUnit4;
+
+@RunWith(JUnit4.class)
+public class DirStatTests {
+  @Test
+  public void correctStatsInTestdir() throws Exception {
+    File testDir = new File("src/test/resources/testdir");
+    assertThat(testDir.isDirectory()).isTrue();
+
+    DirSize test = new DirSize();
+    DirStats stats = test.dirStats(testDir).get();
+    assertThat(stats.fileCount).isEqualTo(38);
+    assertThat(stats.totalSize).isEqualTo(3230);
+  }
+}