Added support for Scala to CPD.

The Scala tokenizer was extracted from the Sonar Scala plugin.
(https://github.com/SonarCommunity/sonar-scala) I copied the code
because the Sonar Scala plugin has a lot of unwanted dependencies. I
tried to keep the changes to the Scala Sonar plugin as minimal as
possible.

To tokenize the source files the official Scala compiler is used.

pmd-scala/pom.xml

@@ -0,0 +1,92 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
+    <modelVersion>4.0.0</modelVersion>
+    <artifactId>pmd-scala</artifactId>
+    <name>PMD Scala</name>
+
+    <parent>
+        <groupId>net.sourceforge.pmd</groupId>
+        <artifactId>pmd</artifactId>
+        <version>5.2.4-SNAPSHOT</version>
+    </parent>
+
+    <properties>
+        <scala.version>2.10.4</scala.version>
+    </properties>
+
+    <build>
+        <pluginManagement>
+            <plugins>
+                <plugin>
+                    <groupId>net.alchim31.maven</groupId>
+                    <artifactId>scala-maven-plugin</artifactId>
+                    <version>3.2.0</version>
+                </plugin>
+            </plugins>
+        </pluginManagement>
+
+        <plugins>
+            <plugin>
+                <artifactId>maven-resources-plugin</artifactId>
+                <configuration>
+                    <useDefaultDelimiters>false</useDefaultDelimiters>
+                    <delimiters>
+                        <delimiter>${*}</delimiter>
+                    </delimiters>
+                </configuration>
+            </plugin>
+
+            <plugin>
+                <groupId>net.alchim31.maven</groupId>
+                <artifactId>scala-maven-plugin</artifactId>
+                <executions>
+                    <execution>
+                        <id>scala-compile-first</id>
+                        <phase>process-resources</phase>
+                        <goals>
+                            <goal>add-source</goal>
+                            <goal>compile</goal>
+                        </goals>
+                    </execution>
+                </executions>
+            </plugin>
+
+            <plugin>
+                <groupId>org.apache.maven.plugins</groupId>
+                <artifactId>maven-site-plugin</artifactId>
+                <configuration>
+                    <xdocDirectory>${project.build.directory}/generated-xdocs</xdocDirectory>
+                </configuration>
+            </plugin>
+
+        </plugins>
+    </build>
+
+    <dependencies>
+        <dependency>
+            <groupId>org.scala-lang</groupId>
+            <artifactId>scala-library</artifactId>
+            <version>${scala.version}</version>
+        </dependency>
+        <dependency>
+            <groupId>org.scala-lang</groupId>
+            <artifactId>scala-compiler</artifactId>
+            <version>${scala.version}</version>
+        </dependency>
+        <dependency>
+            <groupId>net.sourceforge.pmd</groupId>
+            <artifactId>pmd-core</artifactId>
+        </dependency>
+
+        <dependency>
+            <groupId>junit</groupId>
+            <artifactId>junit</artifactId>
+            <scope>test</scope>
+        </dependency>
+        <dependency>
+            <groupId>net.sourceforge.pmd</groupId>
+            <artifactId>pmd-test</artifactId>
+            <scope>test</scope>
+        </dependency>
+    </dependencies>
+</project>

pmd-scala/src/main/java/net/sourceforge/pmd/cpd/ScalaLanguage.java

@@ -0,0 +1,19 @@
+/**
+ * BSD-style license; for more info see http://pmd.sourceforge.net/license.html
+ */
+package net.sourceforge.pmd.cpd;
+
+import org.sonar.plugins.scala.cpd.ScalaTokenizer;
+
+/**
+ * Language implementation for Scala
+ */
+public class ScalaLanguage extends AbstractLanguage {
+
+    /**
+     * Creates a new Scala Language instance.
+     */
+    public ScalaLanguage() {
+        super("Scala", "scala", new ScalaTokenizer(), ".scala");
+    }
+}

pmd-scala/src/main/java/net/sourceforge/pmd/lang/scala/ScalaLanguageModule.java

@@ -0,0 +1,25 @@
+/**
+ * BSD-style license; for more info see http://pmd.sourceforge.net/license.html
+ */
+package net.sourceforge.pmd.lang.scala;
+
+import net.sourceforge.pmd.lang.BaseLanguageModule;
+
+/**
+ * Language Module for Scala
+ */
+public class ScalaLanguageModule extends BaseLanguageModule {
+
+    /** The name. */
+    public static final String NAME = "Scala";
+    /** The terse name. */
+    public static final String TERSE_NAME = "scala";
+
+    /**
+     * Create a new instance of Scala Language Module.
+     */
+    public ScalaLanguageModule() {
+        super(NAME, null, TERSE_NAME, null, "scala");
+        addVersion("", null, true);
+    }
+}

pmd-scala/src/main/java/org/sonar/plugins/scala/cpd/ScalaTokenizer.java

@@ -0,0 +1,55 @@
+/*
+ * Sonar Scala Plugin
+ * Copyright (C) 2011 - 2014 All contributors
+ * dev@sonar.codehaus.org
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 3 of the License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02
+ */
+package org.sonar.plugins.scala.cpd;
+
+import java.util.List;
+
+import net.sourceforge.pmd.cpd.SourceCode;
+import net.sourceforge.pmd.cpd.TokenEntry;
+import net.sourceforge.pmd.cpd.Tokenizer;
+import net.sourceforge.pmd.cpd.Tokens;
+
+import org.sonar.plugins.scala.compiler.Lexer;
+import org.sonar.plugins.scala.compiler.Token;
+
+/**
+ * Scala tokenizer for PMD CPD.
+ *
+ * @since 0.1
+ */
+public final class ScalaTokenizer implements Tokenizer {
+
+  public void tokenize(SourceCode source, Tokens cpdTokens) {
+    String filename = source.getFileName();
+
+    Lexer lexer = new Lexer();
+    List<Token> tokens =  lexer.getTokensOfFile(filename);
+    for (Token token : tokens) {
+      String tokenVal =
+        token.tokenVal() != null ? token.tokenVal()  : Integer.toString(token.tokenType());
+
+      TokenEntry cpdToken = new TokenEntry(tokenVal, filename, token.line());
+      cpdTokens.add(cpdToken);
+    }
+
+    cpdTokens.add(TokenEntry.getEOF());
+  }
+
+}

pmd-scala/src/main/java/org/sonar/plugins/scala/language/Comment.java

@@ -0,0 +1,119 @@
+/*
+ * Sonar Scala Plugin
+ * Copyright (C) 2011 - 2014 All contributors
+ * dev@sonar.codehaus.org
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 3 of the License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02
+ */
+package org.sonar.plugins.scala.language;
+
+import java.io.IOException;
+import java.util.List;
+
+import org.apache.commons.lang3.builder.EqualsBuilder;
+import org.apache.commons.lang3.builder.HashCodeBuilder;
+import org.apache.commons.lang3.builder.ToStringBuilder;
+import org.sonar.plugins.scala.util.StringUtils;
+
+/**
+ * This class implements a Scala comment and the computation
+ * of several base metrics for a comment.
+ *
+ * @author Felix Müller
+ * @since 0.1
+ */
+public class Comment {
+
+  private final CommentType type;
+  private final List<String> lines;
+
+  public Comment(String content, CommentType type) throws IOException {
+    lines = StringUtils.convertStringToListOfLines(content);
+    this.type = type;
+  }
+
+  public int getNumberOfLines() {
+    return lines.size() - getNumberOfBlankLines() - getNumberOfCommentedOutLinesOfCode();
+  }
+
+  public int getNumberOfBlankLines() {
+    int numberOfBlankLines = 0;
+    for (String comment : lines) {
+      boolean isBlank = true;
+
+      for (int i = 0; isBlank && i < comment.length(); i++) {
+        char character = comment.charAt(i);
+        if (!Character.isWhitespace(character) && character != '*' && character != '/') {
+          isBlank = false;
+        }
+      }
+
+      if (isBlank) {
+        numberOfBlankLines++;
+      }
+    }
+    return numberOfBlankLines;
+  }
+
+  public int getNumberOfCommentedOutLinesOfCode() {
+    if (isDocComment()) {
+      return 0;
+    }
+
+    int numberOfCommentedOutLinesOfCode = 0;
+    for (String line : lines) {
+      String strippedLine = org.apache.commons.lang3.StringUtils.strip(line, " /*");
+      if (CodeDetector.hasDetectedCode(strippedLine)) {
+        numberOfCommentedOutLinesOfCode++;
+      }
+    }
+    return numberOfCommentedOutLinesOfCode;
+  }
+
+  public boolean isDocComment() {
+    return type == CommentType.DOC;
+  }
+
+  public boolean isHeaderComment() {
+    return type == CommentType.HEADER;
+  }
+
+  @Override
+  public int hashCode() {
+    return new HashCodeBuilder().append(type).append(lines).toHashCode();
+  }
+
+  @Override
+  public boolean equals(Object obj) {
+    if (!(obj instanceof Comment)) {
+      return false;
+    }
+
+    Comment other = (Comment) obj;
+    return new EqualsBuilder().append(type, other.type).append(lines, other.lines).isEquals();
+  }
+
+  @Override
+  public String toString() {
+    final String firstLine = lines.isEmpty() ? "" : lines.get(0);
+    final String lastLine = lines.isEmpty() ? "" : lines.get(lines.size() - 1);
+    return new ToStringBuilder(this).append("type", type)
+        .append("firstLine", firstLine)
+        .append("lastLine", lastLine)
+        .append("numberOfLines", getNumberOfLines())
+        .append("numberOfCommentedOutLinesOfCode", getNumberOfCommentedOutLinesOfCode())
+        .toString();
+  }
+}

pmd-scala/src/main/java/org/sonar/plugins/scala/language/CommentType.java

@@ -0,0 +1,34 @@
+/*
+ * Sonar Scala Plugin
+ * Copyright (C) 2011 - 2014 All contributors
+ * dev@sonar.codehaus.org
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 3 of the License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02
+ */
+package org.sonar.plugins.scala.language;
+
+/**
+ * This enum is a helper to distinguish between the
+ * different types of comments in Sonar.
+ *
+ * @author Felix Müller
+ * @since 0.1
+ */
+public enum CommentType {
+
+  NORMAL,
+  DOC,
+  HEADER;
+}

pmd-scala/src/main/java/org/sonar/plugins/scala/util/StringUtils.java

@@ -0,0 +1,51 @@
+/*
+ * Sonar Scala Plugin
+ * Copyright (C) 2011 - 2014 All contributors
+ * dev@sonar.codehaus.org
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 3 of the License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02
+ */
+package org.sonar.plugins.scala.util;
+
+import java.io.BufferedReader;
+import java.io.IOException;
+import java.io.StringReader;
+import java.util.ArrayList;
+import java.util.List;
+
+import org.apache.commons.io.IOUtils;
+
+public final class StringUtils {
+  private StringUtils() {
+    // to prevent instantiation
+  }
+
+  public static List<String> convertStringToListOfLines(String string) throws IOException {
+    final List<String> lines = new ArrayList<String>();
+    BufferedReader reader = null;
+    try {
+      reader = new BufferedReader(new StringReader(string));
+      String line = null;
+      while ((line = reader.readLine()) != null) {
+        lines.add(line);
+      }
+    } catch (IOException ioe) {
+      throw ioe;
+    } finally {
+      IOUtils.closeQuietly(reader);
+    }
+    return lines;
+  }
+}

pmd-scala/src/main/resources/META-INF/services/net.sourceforge.pmd.cpd.Language

@@ -0,0 +1 @@
+net.sourceforge.pmd.cpd.ScalaLanguage

pmd-scala/src/main/resources/META-INF/services/net.sourceforge.pmd.lang.Language

@@ -0,0 +1 @@
+net.sourceforge.pmd.lang.scala.ScalaLanguageModule

pmd-scala/src/main/scala/org/sonar/plugins/scala/compiler/Compiler.scala

@@ -0,0 +1,33 @@
+/*
+ * Sonar Scala Plugin
+ * Copyright (C) 2011 - 2014 All contributors
+ * dev@sonar.codehaus.org
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 3 of the License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02
+ */
+package org.sonar.plugins.scala.compiler
+
+import scala.tools.nsc.{Settings, Global}
+
+/**
+ * This is a wrapper for the Scala compiler. It is used to access
+ * the compiler in a more convenient way.
+ *
+ * @author Felix Müller
+ * @since 0.1
+ */
+object Compiler extends Global(new Settings()) {
+  override def forScaladoc = true
+}

pmd-scala/src/main/scala/org/sonar/plugins/scala/compiler/Lexer.scala

@@ -0,0 +1,128 @@
+/*
+ * Sonar Scala Plugin
+ * Copyright (C) 2011 - 2014 All contributors
+ * dev@sonar.codehaus.org
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 3 of the License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02
+ */
+package org.sonar.plugins.scala.compiler
+
+import collection.mutable.ListBuffer
+
+import org.sonar.plugins.scala.language.{Comment, CommentType}
+import scala.reflect.io.AbstractFile
+import scala.reflect.internal.util.BatchSourceFile
+
+/**
+ * This class is a wrapper for accessing the lexer of the Scala compiler
+ * from Java in a more convenient way.
+ *
+ * @author Felix Müller
+ * @since 0.1
+ */
+class Lexer {
+
+  import scala.collection.JavaConversions._
+  import Compiler._
+
+  def getTokens(code: String): java.util.List[Token] = {
+    val unit = new CompilationUnit(new BatchSourceFile("", code.toCharArray))
+    tokenize(unit)
+  }
+
+  def getTokensOfFile(path: String): java.util.List[Token] = {
+    val unit = new CompilationUnit(new BatchSourceFile(AbstractFile.getFile(path)))
+    tokenize(unit)
+  }
+
+  private def tokenize(unit: CompilationUnit): java.util.List[Token] = {
+    val scanner = new syntaxAnalyzer.UnitScanner(unit)
+    val tokens = ListBuffer[Token]()
+
+    scanner.init()
+    while (scanner.token != scala.tools.nsc.ast.parser.Tokens.EOF) {
+      val tokenVal =
+        if (scala.tools.nsc.ast.parser.Tokens.isIdentifier(scanner.token)) scanner.name.toString() else null
+      val linenr = scanner.parensAnalyzer.line(scanner.offset) + 1
+
+      tokens += Token(scanner.token, linenr, tokenVal)
+      scanner.nextToken()
+    }
+    tokens
+  }
+
+  def getComments(code: String): java.util.List[Comment] = {
+    val unit = new CompilationUnit(new BatchSourceFile("", code.toCharArray))
+    tokenizeComments(unit)
+  }
+
+  def getCommentsOfFile(path: String): java.util.List[Comment] = {
+    val unit = new CompilationUnit(new BatchSourceFile(AbstractFile.getFile(path)))
+    tokenizeComments(unit)
+  }
+
+  private def tokenizeComments(unit: CompilationUnit): java.util.List[Comment] = {
+    val comments = ListBuffer[Comment]()
+    val scanner = new syntaxAnalyzer.UnitScanner(unit) {
+
+      private var lastDocCommentRange: Option[Range] = None
+
+      private var foundToken = false
+
+      override def nextToken() {
+        super.nextToken()
+        foundToken = token != 0
+      }
+
+      override def foundComment(value: String, start: Int, end: Int) = {
+        super.foundComment(value, start, end)
+
+        def isHeaderComment(value: String) = {
+          !foundToken && comments.isEmpty && value.trim().startsWith("/*")
+        }
+
+        lastDocCommentRange match {
+
+          case Some(r: Range) => {
+            if (r.start != start || r.end != end) {
+              comments += new Comment(value, CommentType.NORMAL)
+            }
+          }
+
+          case None => {
+            if (isHeaderComment(value)) {
+              comments += new Comment(value, CommentType.HEADER)
+            } else {
+              comments += new Comment(value, CommentType.NORMAL)
+            }
+          }
+        }
+      }
+
+      override def foundDocComment(value: String, start: Int, end: Int) = {
+        super.foundDocComment(value, start, end)
+        comments += new Comment(value, CommentType.DOC)
+        lastDocCommentRange = Some(Range(start, end))
+      }
+    }
+
+    scanner.init()
+    while (scanner.token != scala.tools.nsc.ast.parser.Tokens.EOF) {
+      scanner.nextToken()
+    }
+
+    comments
+  }
+}

pmd-scala/src/main/scala/org/sonar/plugins/scala/compiler/Parser.scala

@@ -0,0 +1,61 @@
+/*
+ * Sonar Scala Plugin
+ * Copyright (C) 2011 - 2014 All contributors
+ * dev@sonar.codehaus.org
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 3 of the License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02
+ */
+package org.sonar.plugins.scala.compiler
+
+import scala.reflect.internal.util.{ScriptSourceFile, BatchSourceFile}
+import scala.reflect.io.AbstractFile
+
+/**
+ * This class is a wrapper for accessing the parser of the Scala compiler
+ * from Java in a more convenient way.
+ *
+ * @author Felix Müller
+ * @since 0.1
+ */
+class Parser {
+
+  import Compiler._
+
+  def parse(code: String): Tree = {
+    val batchSourceFile = new BatchSourceFile("", code.toCharArray)
+    parse(batchSourceFile, code.toCharArray)
+  }
+
+  def parseFile(path: String): Tree = {
+    val batchSourceFile = new BatchSourceFile(AbstractFile.getFile(path))
+    parse(batchSourceFile, batchSourceFile.content.array)
+  }
+
+  private def parse(batchSourceFile: BatchSourceFile, code: Array[Char]): Tree = {
+    try {
+      val parser = new syntaxAnalyzer.SourceFileParser(new ScriptSourceFile(batchSourceFile, code, 0))
+      val tree = parser.templateStatSeq(false)._2
+      parser.makePackaging(0, parser.atPos(0, 0, 0)(Ident(nme.EMPTY_PACKAGE_NAME)), tree)
+    } catch {
+      case _: Throwable => {
+        val unit = new CompilationUnit(batchSourceFile)
+        val unitParser = new syntaxAnalyzer.UnitParser(unit) {
+          override def showSyntaxErrors() {}
+        }
+        unitParser.smartParse()
+      }
+    }
+  }
+}

pmd-scala/src/main/scala/org/sonar/plugins/scala/compiler/Token.scala

@@ -0,0 +1,27 @@
+/*
+ * Sonar Scala Plugin
+ * Copyright (C) 2011 - 2014 All contributors
+ * dev@sonar.codehaus.org
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 3 of the License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02
+ */
+package org.sonar.plugins.scala.compiler
+
+/**
+ * Represent a token. Lines must start at 1.
+ *
+ * @since 0.1
+ */
+case class Token(tokenType: Int, line: Int, tokenVal: String)

pmd-scala/src/main/scala/org/sonar/plugins/scala/language/CodeDetector.scala

@@ -0,0 +1,66 @@
+/*
+ * Sonar Scala Plugin
+ * Copyright (C) 2011 - 2014 All contributors
+ * dev@sonar.codehaus.org
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 3 of the License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02
+ */
+package org.sonar.plugins.scala.language
+
+import org.sonar.plugins.scala.compiler.{ Compiler, Parser }
+
+/**
+ * This object is a helper object for detecting valid Scala code
+ * in a given piece of source code.
+ *
+ * @author Felix Müller
+ * @since 0.1
+ */
+object CodeDetector {
+
+  import Compiler._
+
+  private lazy val parser = new Parser()
+
+  def hasDetectedCode(code: String) = {
+
+    def lookingForSyntaxTreesWithCode(tree: Tree) : Boolean = tree match {
+
+      case PackageDef(identifier: RefTree, content) =>
+        if (!identifier.name.equals(nme.EMPTY_PACKAGE_NAME)) {
+          true
+        } else {
+          content.exists(lookingForSyntaxTreesWithCode)
+        }
+
+      case Apply(function, args) =>
+        args.exists(lookingForSyntaxTreesWithCode)
+
+      case ClassDef(_, _, _, _)
+        | ModuleDef(_, _, _)
+        | ValDef(_, _, _, _)
+        | DefDef(_, _, _, _, _, _)
+        | Function(_ , _)
+        | Assign(_, _)
+        | LabelDef(_, _, _) =>
+          true
+
+      case _ =>
+        false
+    }
+
+    lookingForSyntaxTreesWithCode(parser.parse(code))
+  }
+}

pmd-scala/src/site/markdown/index.md

@@ -0,0 +1,3 @@
+# PMD Scala
+
+Only CPD is supported. There are no PMD rules for Scala.

pmd-scala/src/site/site.xml

@@ -0,0 +1,12 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<project
+  xmlns="http://maven.apache.org/DECORATION/1.1.0"
+  xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+  xsi:schemaLocation="http://maven.apache.org/DECORATION/1.1.0 http://maven.apache.org/xsd/decoration-1.1.0.xsd"
+  name="PMD Scala">
+
+  <body>
+    <menu ref="parent"/>
+    <menu ref="reports"/>
+  </body>
+</project>

pmd-scala/src/test/java/net/sourceforge/pmd/LanguageVersionTest.java

@@ -0,0 +1,27 @@
+/**
+ * BSD-style license; for more info see http://pmd.sourceforge.net/license.html
+ */
+package net.sourceforge.pmd;
+
+import java.util.Arrays;
+import java.util.Collection;
+
+import net.sourceforge.pmd.lang.LanguageRegistry;
+import net.sourceforge.pmd.lang.LanguageVersion;
+import net.sourceforge.pmd.lang.scala.ScalaLanguageModule;
+
+import org.junit.runners.Parameterized.Parameters;
+
+public class LanguageVersionTest extends AbstractLanguageVersionTest {
+
+    public LanguageVersionTest(String name, String terseName, String version, LanguageVersion expected) {
+        super(name, terseName, version, expected);
+    }
+
+    @Parameters
+    public static Collection<Object[]> data() {
+        return Arrays.asList(new Object[][] {
+                { ScalaLanguageModule.NAME, ScalaLanguageModule.TERSE_NAME, "", LanguageRegistry.getLanguage(ScalaLanguageModule.NAME).getDefaultVersion() }
+            });
+    }
+}

pmd-scala/src/test/java/net/sourceforge/pmd/cpd/ScalaTokenizerTest.java

@@ -0,0 +1,64 @@
+/**
+ * BSD-style license; for more info see http://pmd.sourceforge.net/license.html
+ */
+package net.sourceforge.pmd.cpd;
+
+import java.io.File;
+import java.io.IOException;
+
+import net.sourceforge.pmd.testframework.AbstractTokenizerTest;
+import net.sourceforge.pmd.testframework.StreamUtil;
+
+import org.apache.commons.io.FileUtils;
+import org.junit.After;
+import org.junit.Before;
+import org.junit.Test;
+import org.sonar.plugins.scala.cpd.ScalaTokenizer;
+
+
+public class ScalaTokenizerTest extends AbstractTokenizerTest {
+
+    private static final String FILENAME = "sample-LiftActor.scala";
+
+    private File tempFile;
+
+    @Before
+    @Override
+    public void buildTokenizer() {
+        createTempFileOnDisk();
+
+        this.tokenizer = new ScalaTokenizer();
+        this.sourceCode = new SourceCode(new SourceCode.FileCodeLoader(tempFile, "UTF-8"));
+    }
+
+    private void createTempFileOnDisk() {
+        try {
+            this.tempFile = File.createTempFile("scala-tokenizer-test-", ".scala");
+
+            FileUtils.writeStringToFile(tempFile, getSampleCode(), "UTF-8");
+        } catch (IOException e) {
+            throw new RuntimeException("Unable to create temporary file on disk for Scala tokenizer test", e);
+        }
+    }
+
+    @Override
+    public String getSampleCode() {
+        return StreamUtil.toString(ScalaTokenizer.class.getResourceAsStream(FILENAME));
+    }
+
+    @Test
+    public void tokenizeTest() throws IOException {
+        this.expectedTokenCount = 2591;
+        super.tokenizeTest();
+    }
+
+    @After
+    public void cleanUp() {
+        FileUtils.deleteQuietly(this.tempFile);
+        this.tempFile = null;
+    }
+
+    public static junit.framework.Test suite() {
+        return new junit.framework.JUnit4TestAdapter(ScalaTokenizerTest.class);
+    }
+}

pom.xml

@@ -867,6 +867,7 @@
         <module>pmd-php</module>
         <module>pmd-plsql</module>
         <module>pmd-ruby</module>
+        <module>pmd-scala</module>
         <module>pmd-test</module>
         <module>pmd-vm</module>
         <module>pmd-xml</module>