[scala] Add Scalastyle, use scalastyle-config.xml from Spark

.gitignore

 .cache
+scalastyle-output.xml
 .classpath
 .idea
 .metadata

flink-examples/flink-scala-examples/src/main/scala/org/apache/flink/examples/scala/graph/ConnectedComponents.scala

@@ -71,7 +71,8 @@ object ConnectedComponents {
     // assign the initial components (equal to the vertex id)
     val vertices = getVerticesDataSet(env).map { id => (id, id) }
 
-    // undirected edges by emitting for each input edge the input edges itself and an inverted version
+    // undirected edges by emitting for each input edge the input edges itself and an inverted
+    // version
     val edges = getEdgesDataSet(env).flatMap { edge => Seq(edge, (edge._2, edge._1)) }
 
     // open a delta iteration
@@ -113,13 +114,15 @@ object ConnectedComponents {
         outputPath = args(2)
         maxIterations = args(3).toInt
       } else {
-        System.err.println("Usage: ConnectedComponents <vertices path> <edges path> <result path> <max number of iterations>")
+        System.err.println("Usage: ConnectedComponents <vertices path> <edges path> <result path>" +
+          " <max number of iterations>")
         false
       }
     } else {
       System.out.println("Executing Connected Components example with built-in default data.")
       System.out.println("  Provide parameters to read input data from a file.")
-      System.out.println("  Usage: ConnectedComponents <vertices path> <edges path> <result path> <max number of iterations>")
+      System.out.println("  Usage: ConnectedComponents <vertices path> <edges path> <result path>" +
+        " <max number of iterations>")
     }
     true
   }

flink-examples/flink-scala-examples/src/main/scala/org/apache/flink/examples/scala/graph/EnumTrianglesBasic.scala

@@ -110,9 +110,9 @@ object EnumTrianglesBasic {
   // *************************************************************************
 
   /**
-	 *  Builds triads (triples of vertices) from pairs of edges that share a vertex.
-	 *  The first vertex of a triad is the shared vertex, the second and third vertex are ordered by vertexId. 
-	 *  Assumes that input edges share the first vertex and are in ascending order of the second vertex.
+   *  Builds triads (triples of vertices) from pairs of edges that share a vertex. The first vertex
+   *  of a triad is the shared vertex, the second and third vertex are ordered by vertexId. Assumes
+   *  that input edges share the first vertex and are in ascending order of the second vertex.
    */
   class TriadBuilder extends GroupReduceFunction[Edge, Triad] {
 
@@ -162,7 +162,9 @@ object EnumTrianglesBasic {
     if (fileOutput) {
       env.readCsvFile[Edge](edgePath, fieldDelimiter = ' ', includedFields = Array(0, 1))
     } else {
-			val edges = EnumTrianglesData.EDGES.map{ case Array(v1, v2) => new Edge(v1.asInstanceOf[Int], v2.asInstanceOf[Int]) }
+      val edges = EnumTrianglesData.EDGES.map {
+        case Array(v1, v2) => new Edge(v1.asInstanceOf[Int], v2.asInstanceOf[Int])
+      }
       env.fromCollection(edges)
     }
   }

flink-examples/flink-scala-examples/src/main/scala/org/apache/flink/examples/scala/graph/PageRankBasic.scala

@@ -86,7 +86,9 @@ object PageRankBasic {
       // initialize lists
       .map(e => AdjacencyList(e.sourceId, Array(e.targetId)))
       // concatenate lists
-      .groupBy("sourceId").reduce((l1, l2) => AdjacencyList(l1.sourceId, l1.targetIds ++ l2.targetIds))
+      .groupBy("sourceId").reduce {
+      (l1, l2) => AdjacencyList(l1.sourceId, l1.targetIds ++ l2.targetIds)
+      }
 
     // start iteration
     val finalRanks = pagesWithRanks.iterateWithTermination(maxIterations) {

flink-examples/flink-scala-examples/src/main/scala/org/apache/flink/examples/scala/graph/TransitiveClosureNaive.scala

@@ -49,17 +49,17 @@ object TransitiveClosureNaive {
           (prev, next, out: Collector[(Long, Long)]) => {
             val prevPaths = prev.toSet
             for (n <- next)
-							if (!prevPaths.contains(n))
-								out.collect(n)
+              if (!prevPaths.contains(n)) out.collect(n)
           }
       }
       (nextPaths, terminate)
     }
 
-		if (fileOutput)
+    if (fileOutput) {
       paths.writeAsCsv(outputPath, "\n", " ")
-		else
+    } else {
       paths.print()
+    }
 
     env.execute("Scala Transitive Closure Example")
 
@@ -81,15 +81,18 @@ object TransitiveClosureNaive {
         maxIterations = Integer.parseInt(programArguments(2))
       }
       else {
-				System.err.println("Usage: TransitiveClosure <edges path> <result path> <max number of iterations>")
+        System.err.println("Usage: TransitiveClosure <edges path> <result path> <max number of " +
+          "iterations>")
         return false
       }
     }
     else {
-			System.out.println("Executing TransitiveClosure example with default parameters and built-in default data.")
+      System.out.println("Executing TransitiveClosure example with default parameters and " +
+        "built-in default data.")
       System.out.println("  Provide parameters to read input data from files.")
       System.out.println("  See the documentation for the correct format of input files.")
-			System.out.println("  Usage: TransitiveClosure <edges path> <result path> <max number of iterations>")
+      System.out.println("  Usage: TransitiveClosure <edges path> <result path> <max number of " +
+        "iterations>")
     }
     true
   }

flink-examples/flink-scala-examples/src/main/scala/org/apache/flink/examples/scala/misc/PiEstimation.scala

@@ -37,7 +37,7 @@ object PiEstimation {
           val y = Math.random()
           if (x * x + y * y < 1) 1L else 0L
         }
-        .reduce(_+_)
+        .reduce(_ + _)
 
     // ratio of samples in upper right quadrant vs total samples gives surface of upper
     // right quadrant, times 4 gives surface of whole unit circle, i.e. PI

flink-examples/flink-scala-examples/src/main/scala/org/apache/flink/examples/scala/ml/LinearRegression.scala

@@ -104,7 +104,7 @@ object LinearRegression {
       Params(theta0 / a, theta1 / a)
     }
 
-    def +(other: Params) = {
+    def + (other: Params) = {
       Params(theta0 + other.theta0, theta1 + other.theta1)
     }
   }

flink-scala/src/main/scala/org/apache/flink/api/scala/DataSet.scala

@@ -15,7 +15,6 @@
  * See the License for the specific language governing permissions and
  * limitations under the License.
  */
-
 package org.apache.flink.api.scala
 
 import org.apache.commons.lang3.Validate
@@ -825,6 +824,28 @@ class DataSet[T: ClassTag](private[flink] val set: JavaDataSet[T]) {
     wrap(result)
   }
 
+  /**
+   * Creates a new DataSet by performing delta (or workset) iterations using the given step
+   * function. At the beginning `this` DataSet is the solution set and `workset` is the Workset.
+   * The iteration step function gets the current solution set and workset and must output the
+   * delta for the solution set and the workset for the next iteration.
+   *
+   * Note: The syntax of delta iterations are very likely going to change soon.
+   */
+  def iterateDelta[R: ClassTag](workset: DataSet[R], maxIterations: Int, keyFields: Array[String])(
+    stepFunction: (DataSet[T], DataSet[R]) => (DataSet[T], DataSet[R])) = {
+    val fieldIndices = fieldNames2Indices(set.getType, keyFields)
+
+    val key = new FieldPositionKeys[T](fieldIndices, set.getType, false)
+    val iterativeSet = new DeltaIteration[T, R](
+      set.getExecutionEnvironment, set.getType, set, workset.set, key, maxIterations)
+    val (newSolution, newWorkset) = stepFunction(
+      wrap(iterativeSet.getSolutionSet),
+      wrap(iterativeSet.getWorkset))
+    val result = iterativeSet.closeWith(newSolution.set, newWorkset.set)
+    wrap(result)
+  }
+
   // -------------------------------------------------------------------------------------------
   //  Custom Operators
   // -------------------------------------------------------------------------------------------

flink-scala/src/main/scala/org/apache/flink/api/scala/ExecutionEnvironment.scala

@@ -22,7 +22,7 @@ import java.util.UUID
 import org.apache.commons.lang3.Validate
 import org.apache.flink.api.common.JobExecutionResult
 import org.apache.flink.api.java.io._
-import org.apache.flink.api.java.typeutils.{TupleTypeInfoBase, BasicTypeInfo}
+import org.apache.flink.api.java.typeutils.{ValueTypeInfo, TupleTypeInfoBase, BasicTypeInfo}
 import org.apache.flink.api.scala.operators.ScalaCsvInputFormat
 import org.apache.flink.core.fs.Path
 
@@ -30,7 +30,7 @@ import org.apache.flink.api.java.{ExecutionEnvironment => JavaEnv}
 import org.apache.flink.api.common.io.{InputFormat, FileInputFormat}
 
 import org.apache.flink.api.java.operators.DataSource
-import org.apache.flink.types.TypeInformation
+import org.apache.flink.types.{StringValue, TypeInformation}
 import org.apache.flink.util.{NumberSequenceIterator, SplittableIterator}
 
 import scala.collection.JavaConverters._
@@ -104,6 +104,27 @@ class ExecutionEnvironment(javaEnv: JavaEnv) {
     wrap(source)
   }
 
+  /**
+   * Creates a DataSet of Strings produced by reading the given file line wise.
+   * This method is similar to [[readTextFile]], but it produces a DataSet with mutable
+   * [[StringValue]] objects, rather than Java Strings. StringValues can be used to tune
+   * implementations to be less object and garbage collection heavy.
+   *
+   * @param filePath The path of the file, as a URI (e.g., "file:///some/local/file" or
+   *                 "hdfs://host:port/file/path").
+   * @param charsetName The name of the character set used to read the file. Default is UTF-0
+   */
+  def readTextFileWithValue(
+      filePath: String,
+      charsetName: String = "UTF-8"): DataSet[StringValue] = {
+    Validate.notNull(filePath, "The file path may not be null.")
+    val format = new TextValueInputFormat(new Path(filePath))
+    format.setCharsetName(charsetName)
+    val source = new DataSource[StringValue](
+      javaEnv, format, new ValueTypeInfo[StringValue](classOf[StringValue]))
+    wrap(source)
+  }
+
   /**
    * Creates a DataSet by reading the given CSV file. The type parameter must be used to specify
    * a Tuple type that has the same number of fields as there are fields in the CSV file. If the
@@ -337,9 +358,10 @@ class ExecutionEnvironment(javaEnv: JavaEnv) {
   def createProgramPlan(jobName: String = "") = {
     if (jobName.isEmpty) {
       javaEnv.createProgramPlan()
-    } else
+    } else {
       javaEnv.createProgramPlan(jobName)
     }
+  }
 }
 
 object ExecutionEnvironment {
@@ -360,7 +382,8 @@ object ExecutionEnvironment {
    * of parallelism of the local environment is the number of hardware contexts (CPU cores/threads).
    */
   def createLocalEnvironment(
-      degreeOfParallelism: Int = Runtime.getRuntime.availableProcessors()) : ExecutionEnvironment = {
+      degreeOfParallelism: Int = Runtime.getRuntime.availableProcessors())
+      : ExecutionEnvironment = {
     val javaEnv = JavaEnv.createLocalEnvironment()
     javaEnv.setDegreeOfParallelism(degreeOfParallelism)
     new ExecutionEnvironment(javaEnv)

flink-scala/src/main/scala/org/apache/flink/api/scala/coGroupDataSet.scala

@@ -33,8 +33,8 @@ import scala.reflect.ClassTag
 
 
 /**
- * A specific [[DataSet]] that results from a `coGroup` operation. The result of a default coGroup is
- * a tuple containing two arrays of values from the two sides of the coGroup. The result of the
+ * A specific [[DataSet]] that results from a `coGroup` operation. The result of a default coGroup
+ * is a tuple containing two arrays of values from the two sides of the coGroup. The result of the
  * coGroup can be changed by specifying a custom coGroup function using the `apply` method or by
  * providing a [[RichCoGroupFunction]].
  *

flink-scala/src/main/scala/org/apache/flink/api/scala/codegen/Counter.scala

@@ -15,8 +15,6 @@
  * See the License for the specific language governing permissions and
  * limitations under the License.
  */
-
-
 package org.apache.flink.api.scala.codegen
 
 private[flink] class Counter {

flink-scala/src/main/scala/org/apache/flink/api/scala/codegen/TreeGen.scala

@@ -15,8 +15,6 @@
  * See the License for the specific language governing permissions and
  * limitations under the License.
  */
-
-
 package org.apache.flink.api.scala.codegen
 
 import scala.language.implicitConversions
@@ -50,11 +48,12 @@ private[flink] trait TreeGen[C <: Context] { this: MacroContextHolder[C] with Ty
       reify(c.Expr(source).splice.asInstanceOf[T]).tree
 
     def maybeMkAsInstanceOf[S: c.WeakTypeTag, T: c.WeakTypeTag](source: Tree): Tree = {
-      if (weakTypeOf[S] <:< weakTypeOf[T])
+      if (weakTypeOf[S] <:< weakTypeOf[T]) {
         source
-      else
+      } else {
         mkAsInstanceOf[T](source)
       }
+    }
 
 //    def mkIdent(target: Symbol): Tree = Ident(target) setType target.tpe
     def mkSelect(rootModule: String, path: String*): Tree =

flink-scala/src/main/scala/org/apache/flink/api/scala/codegen/TypeAnalyzer.scala

@@ -15,8 +15,6 @@
  * See the License for the specific language governing permissions and
  * limitations under the License.
  */
-
-
 package org.apache.flink.api.scala.codegen
 
 import scala.Option.option2Iterable
@@ -107,11 +105,12 @@ private[flink] trait TypeAnalyzer[C <: Context] { this: MacroContextHolder[C]
             appliedType(d.asType.toType, dArgs)
           }
 
-        if (dTpe <:< tpe)
+        if (dTpe <:< tpe) {
           Some(analyze(dTpe))
-        else
+        } else {
           None
         }
+      }
 
       val errors = subTypes flatMap { _.findByType[UnsupportedDescriptor] }
 
@@ -150,7 +149,11 @@ private[flink] trait TypeAnalyzer[C <: Context] { this: MacroContextHolder[C]
                 case true =>
                   Some(
                     FieldAccessor(
-                      bGetter, bSetter, bTpe, isBaseField = true, analyze(bTpe.termSymbol.asMethod.returnType)))
+                      bGetter,
+                      bSetter,
+                      bTpe,
+                      isBaseField = true,
+                      analyze(bTpe.termSymbol.asMethod.returnType)))
                 case false => None
               }
           }
@@ -167,7 +170,9 @@ private[flink] trait TypeAnalyzer[C <: Context] { this: MacroContextHolder[C]
 
             desc match {
               case desc @ BaseClassDescriptor(_, _, getters, baseSubTypes) =>
-                desc.copy(getters = getters map updateField, subTypes = baseSubTypes map wireBaseFields)
+                desc.copy(
+                  getters = getters map updateField,
+                  subTypes = baseSubTypes map wireBaseFields)
               case desc @ CaseClassDescriptor(_, _, _, _, getters) =>
                 desc.copy(getters = getters map updateField)
               case _ => desc
@@ -221,7 +226,7 @@ private[flink] trait TypeAnalyzer[C <: Context] { this: MacroContextHolder[C]
                 case errs @ _ :: _ =>
                   val msgs = errs flatMap { f =>
                     (f: @unchecked) match {
-                      case FieldAccessor(fgetter, _, _, _, UnsupportedDescriptor(_, fTpe, errors)) =>
+                      case FieldAccessor(fgetter, _,_,_, UnsupportedDescriptor(_, fTpe, errors)) =>
                         errors map { err => "Field " + fgetter.name + ": " + fTpe + " - " + err }
                     }
                   }

flink-scala/src/main/scala/org/apache/flink/api/scala/codegen/TypeDescriptors.scala

@@ -15,8 +15,6 @@
  * See the License for the specific language governing permissions and
  * limitations under the License.
  */
-
-
 package org.apache.flink.api.scala.codegen
 
 import scala.language.postfixOps
@@ -122,7 +120,8 @@ private[flink] trait TypeDescriptors[C <: Context] { this: MacroContextHolder[C]
       id: Int, tpe: Type, override val getters: Seq[FieldAccessor], subTypes: Seq[UDTDescriptor])
     extends UDTDescriptor {
 
-    override def flatten = this +: ((getters flatMap { _.desc.flatten }) ++ (subTypes flatMap { _.flatten }))
+    override def flatten =
+      this +: ((getters flatMap { _.desc.flatten }) ++ (subTypes flatMap { _.flatten }))
     override def canBeKey = flatten forall { f => f.canBeKey }
     
     override def select(path: List[String]): Seq[Option[UDTDescriptor]] = path match {
@@ -151,7 +150,8 @@ private[flink] trait TypeDescriptors[C <: Context] { this: MacroContextHolder[C]
     override def hashCode = (id, tpe, ctor, getters).hashCode
     override def equals(that: Any) = that match {
       case CaseClassDescriptor(thatId, thatTpe, thatMutable, thatCtor, thatGetters) =>
-        (id, tpe, mutable, ctor, getters).equals(thatId, thatTpe, thatMutable, thatCtor, thatGetters)
+        (id, tpe, mutable, ctor, getters).equals(
+          thatId, thatTpe, thatMutable, thatCtor, thatGetters)
       case _ => false
     }
     
@@ -164,7 +164,12 @@ private[flink] trait TypeDescriptors[C <: Context] { this: MacroContextHolder[C]
     }
   }
 
-  case class FieldAccessor(getter: Symbol, setter: Symbol, tpe: Type, isBaseField: Boolean, desc: UDTDescriptor)
+  case class FieldAccessor(
+      getter: Symbol,
+      setter: Symbol,
+      tpe: Type,
+      isBaseField: Boolean,
+      desc: UDTDescriptor)
 
   case class RecursiveDescriptor(id: Int, tpe: Type, refId: Int) extends UDTDescriptor {
     override def flatten = Seq(this)

flink-scala/src/main/scala/org/apache/flink/api/scala/codegen/TypeInformationGen.scala

@@ -15,8 +15,6 @@
  * See the License for the specific language governing permissions and
  * limitations under the License.
  */
-
-
 package org.apache.flink.api.scala.codegen
 
 import org.apache.flink.api.common.typeutils.TypeSerializer
@@ -116,14 +114,16 @@ private[flink] trait TypeInformationGen[C <: Context] {
     }
   }
 
-  def mkValueTypeInfo[T <: Value : c.WeakTypeTag](desc: UDTDescriptor): c.Expr[TypeInformation[T]] = {
+  def mkValueTypeInfo[T <: Value : c.WeakTypeTag](
+      desc: UDTDescriptor): c.Expr[TypeInformation[T]] = {
     val tpeClazz = c.Expr[Class[T]](Literal(Constant(desc.tpe)))
     reify {
       new ValueTypeInfo[T](tpeClazz.splice)
     }
   }
 
-  def mkWritableTypeInfo[T <: Writable : c.WeakTypeTag](desc: UDTDescriptor): c.Expr[TypeInformation[T]] = {
+  def mkWritableTypeInfo[T <: Writable : c.WeakTypeTag](
+      desc: UDTDescriptor): c.Expr[TypeInformation[T]] = {
     val tpeClazz = c.Expr[Class[T]](Literal(Constant(desc.tpe)))
     reify {
       new WritableTypeInfo[T](tpeClazz.splice)
@@ -153,7 +153,8 @@ private[flink] trait TypeInformationGen[C <: Context] {
     c.Expr[T](result)
   }
 
-//    def mkCaseClassTypeInfo[T: c.WeakTypeTag](desc: CaseClassDescriptor): c.Expr[TypeInformation[T]] = {
+//    def mkCaseClassTypeInfo[T: c.WeakTypeTag](
+//        desc: CaseClassDescriptor): c.Expr[TypeInformation[T]] = {
 //      val tpeClazz = c.Expr[Class[_]](Literal(Constant(desc.tpe)))
 //      val caseFields = mkCaseFields(desc)
 //      reify {
@@ -178,10 +179,12 @@ private[flink] trait TypeInformationGen[C <: Context] {
 //    c.Expr(mkMap(fields))
 //  }
 //
-//  protected def getFields(name: String, desc: UDTDescriptor): Seq[(String, UDTDescriptor)] = desc match {
+//  protected def getFields(name: String, desc: UDTDescriptor): Seq[(String, UDTDescriptor)] =
+//  desc match {
 //    // Flatten product types
 //    case CaseClassDescriptor(_, _, _, _, getters) =>
-//      getters filterNot { _.isBaseField } flatMap { f => getFields(name + "." + f.getter.name, f.desc) }
+//      getters filterNot { _.isBaseField } flatMap {
+//        f => getFields(name + "." + f.getter.name, f.desc) }
 //    case _ => Seq((name, desc))
 //  }
 }

flink-scala/src/main/scala/org/apache/flink/api/scala/typeutils/ScalaTupleComparator.scala

@@ -15,7 +15,6 @@
  * See the License for the specific language governing permissions and
  * limitations under the License.
  */
-
 package org.apache.flink.api.scala.typeutils
 
 import org.apache.flink.api.common.typeutils.{TypeComparator, TypeSerializer}

flink-scala/src/main/scala/org/apache/flink/api/scala/typeutils/ScalaTupleSerializer.scala

@@ -15,7 +15,6 @@
  * See the License for the specific language governing permissions and
  * limitations under the License.
  */
-
 package org.apache.flink.api.scala.typeutils
 
 import org.apache.flink.api.common.typeutils.TypeSerializer

flink-scala/src/main/scala/org/apache/flink/api/scala/typeutils/ScalaTupleTypeInfo.scala

@@ -15,7 +15,6 @@
  * See the License for the specific language governing permissions and
  * limitations under the License.
  */
-
 package org.apache.flink.api.scala.typeutils
 
 import org.apache.flink.api.java.typeutils.{AtomicType, TupleTypeInfoBase}
@@ -79,8 +78,8 @@ abstract class ScalaTupleTypeInfo[T <: Product](
   def getFieldIndices(fields: Array[String]): Array[Int] = {
     val result = fields map { x => fieldNames.indexOf(x) }
     if (result.contains(-1)) {
-      throw new IllegalArgumentException("Fields '" + fields.mkString(", ") + "' are not valid for" +
-        " " + tupleClass + " with fields '" + fieldNames.mkString(", ") + "'.")
+      throw new IllegalArgumentException("Fields '" + fields.mkString(", ") +
+        "' are not valid for " + tupleClass + " with fields '" + fieldNames.mkString(", ") + "'.")
     }
     result
   }

flink-scala/src/main/scala/org/apache/flink/api/scala/typeutils/TypeUtils.scala

@@ -15,7 +15,6 @@
  * See the License for the specific language governing permissions and
  * limitations under the License.
  */
-
 package org.apache.flink.api.scala.typeutils
 
 import scala.reflect.macros.Context

flink-scala/src/main/scala/org/apache/flink/api/scala/unfinishedKeyPairOperation.scala

@@ -71,7 +71,9 @@ private[flink] abstract class UnfinishedKeyPairOperation[T, O, R](
    * This only works on a CaseClass [[DataSet]].
    */
   def where(firstLeftField: String, otherLeftFields: String*) = {
-    val fieldIndices = fieldNames2Indices(leftSet.set.getType, firstLeftField +: otherLeftFields.toArray)
+    val fieldIndices = fieldNames2Indices(
+      leftSet.set.getType,
+      firstLeftField +: otherLeftFields.toArray)
 
     val leftKey = new FieldPositionKeys[T](fieldIndices, leftSet.set.getType)
     new HalfUnfinishedKeyPairOperation[T, O, R](this, leftKey)

flink-scala/src/test/scala/org/apache/flink/api/scala/ScalaAPICompletenessTest.scala

-/*
- * Licensed to the Apache Software Foundation (ASF) under one or more
- * contributor license agreements.  See the NOTICE file distributed with
- * this work for additional information regarding copyright ownership.
- * The ASF licenses this file to You under the Apache License, Version 2.0
- * (the "License"); you may not use this file except in compliance with
- * the License.  You may obtain a copy of the License at
+/**
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
  *
  * http://www.apache.org/licenses/LICENSE-2.0
  *
@@ -14,7 +15,6 @@
  * See the License for the specific language governing permissions and
  * limitations under the License.
  */
-
 package org.apache.flink.api.scala
 
 import java.lang.reflect.Method
@@ -149,7 +149,8 @@ class ScalaAPICompletenessTest {
     checkMethods("SingleInputOperator", "DataSet",
       classOf[SingleInputOperator[_, _, _]], classOf[DataSet[_]])
 
-    checkMethods("TwoInputOperator", "DataSet", classOf[TwoInputOperator[_, _, _, _]], classOf[DataSet[_]])
+    checkMethods("TwoInputOperator", "DataSet",
+      classOf[TwoInputOperator[_, _, _, _]], classOf[DataSet[_]])
 
     checkMethods("SingleInputUdfOperator", "DataSet",
       classOf[SingleInputUdfOperator[_, _, _]], classOf[DataSet[_]])

flink-scala/src/test/scala/org/apache/flink/api/scala/functions/SemanticPropertiesTranslationTest.scala

@@ -46,7 +46,7 @@ class SemanticPropertiesTranslationTest {
     try {
       val env = ExecutionEnvironment.getExecutionEnvironment
 
-      val input = env.fromElements((3l, "test", 42))
+      val input = env.fromElements((3L, "test", 42))
       input.map(new WildcardConstantMapper[(Long, String, Int)]).print()
 
       val plan = env.createProgramPlan()
@@ -83,7 +83,7 @@ class SemanticPropertiesTranslationTest {
     try {
       val env = ExecutionEnvironment.getExecutionEnvironment
 
-      val input = env.fromElements((3l, "test", 42))
+      val input = env.fromElements((3L, "test", 42))
       input.map(new IndividualConstantMapper[Long, String, Int]).print()
 
       val plan = env.createProgramPlan()
@@ -120,8 +120,8 @@ class SemanticPropertiesTranslationTest {
     try {
       val env = ExecutionEnvironment.getExecutionEnvironment
 
-      val input1 = env.fromElements((3l, "test"))
-      val input2 = env.fromElements((3l, 3.1415))
+      val input1 = env.fromElements((3L, "test"))
+      val input2 = env.fromElements((3L, 3.1415))
 
       input1.join(input2).where(0).equalTo(0)(
         new ForwardingTupleJoin[Long, String, Long, Double]).print()

flink-scala/src/test/scala/org/apache/flink/api/scala/operators/translation/DeltaIterationTranslationTest.scala

@@ -100,7 +100,9 @@ class DeltaIterationTranslationTest {
       assertEquals(classOf[IdentityMapper[_]], worksetMapper.getUserCodeWrapper.getUserCodeClass)
 
 
-      assertEquals(classOf[NextWorksetMapper], nextWorksetMapper.getUserCodeWrapper.getUserCodeClass)
+      assertEquals(
+        classOf[NextWorksetMapper],
+        nextWorksetMapper.getUserCodeWrapper.getUserCodeClass)
 
 
       if (solutionSetJoin.getUserCodeWrapper.getUserCodeObject.isInstanceOf[WrappingFunction[_]]) {
@@ -203,7 +205,8 @@ class DeltaIterationTranslationTest {
 //      val iteration: DeltaIteration[Tuple3[Double, Long, String], Tuple2[Double,
 //        String]] = initialSolutionSet.iterateDelta(initialWorkSet, 10, 1)
 //      try {
-//        iteration.getWorkset.coGroup(iteration.getSolutionSet).where(1).equalTo(2).`with`(new DeltaIterationTranslationTest.SolutionWorksetCoGroup1)
+//        iteration.getWorkset.coGroup(iteration.getSolutionSet).where(1).equalTo(2).`with`(
+// new DeltaIterationTranslationTest.SolutionWorksetCoGroup1)
 //        fail("Accepted invalid program.")
 //      }
 //      catch {
@@ -211,7 +214,8 @@ class DeltaIterationTranslationTest {
 //        }
 //      }
 //      try {
-//        iteration.getSolutionSet.coGroup(iteration.getWorkset).where(2).equalTo(1).`with`(new DeltaIterationTranslationTest.SolutionWorksetCoGroup2)
+//        iteration.getSolutionSet.coGroup(iteration.getWorkset).where(2).equalTo(1).`with`(
+// new DeltaIterationTranslationTest.SolutionWorksetCoGroup2)
 //        fail("Accepted invalid program.")
 //      }
 //      catch {

flink-scala/src/test/scala/org/apache/flink/api/scala/operators/translation/ReduceTranslationTest.scala

@@ -121,7 +121,9 @@ class ReduceTranslationTest {
       assertEquals(keyValueInfo, reducer.getOperatorInfo.getOutputType)
       assertEquals(keyValueInfo, keyProjector.getOperatorInfo.getInputType)
       assertEquals(initialData.set.getType, keyProjector.getOperatorInfo.getOutputType)
-      assertEquals(classOf[KeyExtractingMapper[_, _]], keyExtractor.getUserCodeWrapper.getUserCodeClass)
+      assertEquals(
+        classOf[KeyExtractingMapper[_, _]],
+        keyExtractor.getUserCodeWrapper.getUserCodeClass)
       assertTrue(keyExtractor.getInput.isInstanceOf[GenericDataSourceBase[_, _]])
     }
     catch {

flink-scala/src/test/scala/org/apache/flink/api/scala/runtime/TupleSerializerTest.scala

@@ -34,8 +34,8 @@ class TupleSerializerTest {
 
   @Test
   def testTuple1Int(): Unit = {
-    val testTuples =
-      Array(Tuple1(42), Tuple1(1), Tuple1(0), Tuple1(-1), Tuple1(Int.MaxValue), Tuple1(Int.MinValue))
+    val testTuples = Array(Tuple1(42), Tuple1(1), Tuple1(0), Tuple1(-1), Tuple1(Int.MaxValue),
+      Tuple1(Int.MinValue))
     runTests(testTuples)
   }
 

pom.xml

@@ -522,8 +522,10 @@ under the License.
 						<exclude>**/*.creole</exclude>
 						<exclude>CONTRIBUTORS</exclude>
 						<exclude>DEPENDENCIES</exclude>
-						<!-- Build fiels -->
+						<!-- Build files -->
 						<exclude>tools/maven/checkstyle.xml</exclude>
+						<exclude>tools/maven/scalastyle-config.xml</exclude>
+						<exclude>**/scalastyle-output.xml</exclude>
 						<exclude>tools/maven/suppressions.xml</exclude>
 						<exclude>**/pom.xml</exclude>
 						<exclude>**/pom.hadoop2.xml</exclude>
@@ -555,6 +557,29 @@ under the License.
 					<configLocation>/tools/maven/checkstyle.xml</configLocation>
 					<logViolationsToConsole>true</logViolationsToConsole>
 				</configuration>
+			</plugin>
+			<plugin>
+            	<groupId>org.scalastyle</groupId>
+           		<artifactId>scalastyle-maven-plugin</artifactId>
+            	<version>0.5.0</version>
+            	<configuration>
+              		<verbose>false</verbose>
+              		<failOnViolation>true</failOnViolation>
+              		<includeTestSourceDirectory>true</includeTestSourceDirectory>
+              		<failOnWarning>false</failOnWarning>
+              		<sourceDirectory>${basedir}/src/main/scala</sourceDirectory>
+              		<testSourceDirectory>${basedir}/src/test/scala</testSourceDirectory>
+              		<configLocation>tools/maven/scalastyle-config.xml</configLocation>
+              		<outputFile>${project.basedir}/scalastyle-output.xml</outputFile>
+              		<outputEncoding>UTF-8</outputEncoding>
+            	</configuration>
+            	<executions>
+              		<execution>
+                		<goals>
+                  			<goal>check</goal>
+                		</goals>
+              		</execution>
+            	</executions>
           </plugin>
 			<plugin>
 				<!-- just define the Java version to be used for compiling and plugins -->

tools/maven/scalastyle-config.xml

+<!--
+  ~ Licensed to the Apache Software Foundation (ASF) under one or more
+  ~ contributor license agreements.  See the NOTICE file distributed with
+  ~ this work for additional information regarding copyright ownership.
+  ~ The ASF licenses this file to You under the Apache License, Version 2.0
+  ~ (the "License"); you may not use this file except in compliance with
+  ~ the License.  You may obtain a copy of the License at
+  ~
+  ~    http://www.apache.org/licenses/LICENSE-2.0
+  ~
+  ~ Unless required by applicable law or agreed to in writing, software
+  ~ distributed under the License is distributed on an "AS IS" BASIS,
+  ~ WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+  ~ See the License for the specific language governing permissions and
+  ~ limitations under the License.
+  -->
+<!-- NOTE: This was taken and adapted from Apache Spark. -->
+
+<!-- If you wish to turn off checking for a section of code, you can put a comment in the source
+ before and after the section, with the following syntax: -->
+<!-- // scalastyle:off -->
+<!-- ... -->
+<!-- // naughty stuff -->
+<!-- ... -->
+<!-- // scalastyle:on -->
+
+<scalastyle>
+ <name>Scalastyle standard configuration</name>
+ <check level="error" class="org.scalastyle.file.FileTabChecker" enabled="true"></check>
+ <!-- <check level="error" class="org.scalastyle.file.FileLengthChecker" enabled="true"> -->
+ <!--  <parameters> -->
+ <!--   <parameter name="maxFileLength"><![CDATA[800]]></parameter> -->
+ <!--  </parameters> -->
+ <!-- </check> -->
+ <check level="error" class="org.scalastyle.file.HeaderMatchesChecker" enabled="true">
+  <parameters>
+      <parameter name="header"><![CDATA[/**
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */]]></parameter>
+  </parameters>
+ </check>
+ <check level="error" class="org.scalastyle.scalariform.SpacesAfterPlusChecker" enabled="true"></check>
+ <check level="error" class="org.scalastyle.file.WhitespaceEndOfLineChecker" enabled="false"></check>
+ <check level="error" class="org.scalastyle.scalariform.SpacesBeforePlusChecker" enabled="true"></check>
+ <check level="error" class="org.scalastyle.file.FileLineLengthChecker" enabled="true">
+  <parameters>
+   <parameter name="maxLineLength"><![CDATA[100]]></parameter>
+   <parameter name="tabSize"><![CDATA[2]]></parameter>
+   <parameter name="ignoreImports">true</parameter>
+  </parameters>
+ </check>
+ <check level="error" class="org.scalastyle.scalariform.ClassNamesChecker" enabled="true">
+  <parameters>
+   <parameter name="regex"><![CDATA[[A-Z][A-Za-z]*]]></parameter>
+  </parameters>
+ </check>
+ <check level="error" class="org.scalastyle.scalariform.ObjectNamesChecker" enabled="true">
+  <parameters>
+   <parameter name="regex"><![CDATA[[A-Z][A-Za-z]*]]></parameter>
+  </parameters>
+ </check>
+ <check level="error" class="org.scalastyle.scalariform.PackageObjectNamesChecker" enabled="true">
+  <parameters>
+   <parameter name="regex"><![CDATA[^[a-z][A-Za-z]*$]]></parameter>
+  </parameters>
+ </check>
+ <check level="error" class="org.scalastyle.scalariform.EqualsHashCodeChecker" enabled="false"></check>
+ <!-- <check level="error" class="org.scalastyle.scalariform.IllegalImportsChecker" enabled="true"> -->
+ <!--  <parameters> -->
+ <!--   <parameter name="illegalImports"><![CDATA[sun._,java.awt._]]></parameter> -->
+ <!--  </parameters> -->
+ <!-- </check> -->
+ <check level="error" class="org.scalastyle.scalariform.ParameterNumberChecker" enabled="true">
+  <parameters>
+   <parameter name="maxParameters"><![CDATA[10]]></parameter>
+  </parameters>
+ </check>
+ <!-- <check level="error" class="org.scalastyle.scalariform.MagicNumberChecker" enabled="true"> -->
+ <!--  <parameters> -->
+ <!--   <parameter name="ignore"><![CDATA[-1,0,1,2,3]]></parameter> -->
+ <!--  </parameters> -->
+ <!-- </check> -->
+ <check level="error" class="org.scalastyle.scalariform.NoWhitespaceBeforeLeftBracketChecker" enabled="false"></check>
+ <check level="error" class="org.scalastyle.scalariform.NoWhitespaceAfterLeftBracketChecker" enabled="false"></check>
+ <!-- <check level="error" class="org.scalastyle.scalariform.ReturnChecker" enabled="true"></check> -->
+ <!-- <check level="error" class="org.scalastyle.scalariform.NullChecker" enabled="true"></check> -->
+ <!-- <check level="error" class="org.scalastyle.scalariform.NoCloneChecker" enabled="true"></check> -->
+ <!-- <check level="error" class="org.scalastyle.scalariform.NoFinalizeChecker" enabled="true"></check> -->
+ <!-- <check level="error" class="org.scalastyle.scalariform.CovariantEqualsChecker" enabled="true"></check> -->
+ <!-- <check level="error" class="org.scalastyle.scalariform.StructuralTypeChecker" enabled="true"></check> -->
+ <!-- <check level="error" class="org.scalastyle.file.RegexChecker" enabled="true"> -->
+ <!--  <parameters> -->
+ <!--   <parameter name="regex"><![CDATA[println]]></parameter> -->
+ <!--  </parameters> -->
+ <!-- </check> -->
+ <!-- <check level="error" class="org.scalastyle.scalariform.NumberOfTypesChecker" enabled="true"> -->
+ <!--  <parameters> -->
+ <!--   <parameter name="maxTypes"><![CDATA[30]]></parameter> -->
+ <!--  </parameters> -->
+ <!-- </check> -->
+ <!-- <check level="error" class="org.scalastyle.scalariform.CyclomaticComplexityChecker" enabled="true"> -->
+ <!--  <parameters> -->
+ <!--   <parameter name="maximum"><![CDATA[10]]></parameter> -->
+ <!--  </parameters> -->
+ <!-- </check> -->
+ <check level="error" class="org.scalastyle.scalariform.UppercaseLChecker" enabled="true"></check>
+ <check level="error" class="org.scalastyle.scalariform.SimplifyBooleanExpressionChecker" enabled="false"></check>
+ <check level="error" class="org.scalastyle.scalariform.IfBraceChecker" enabled="true">
+  <parameters>
+   <parameter name="singleLineAllowed"><![CDATA[true]]></parameter>
+   <parameter name="doubleLineAllowed"><![CDATA[true]]></parameter>
+  </parameters>
+ </check>
+ <!-- <check level="error" class="org.scalastyle.scalariform.MethodLengthChecker" enabled="true"> -->
+ <!--  <parameters> -->
+ <!--   <parameter name="maxLength"><![CDATA[50]]></parameter> -->
+ <!--  </parameters> -->
+ <!-- </check> -->
+ <!-- <check level="error" class="org.scalastyle.scalariform.MethodNamesChecker" enabled="true"> -->
+ <!--  <parameters> -->
+ <!--   <parameter name="regex"><![CDATA[^[a-z][A-Za-z0-9]*$]]></parameter> -->
+ <!--  </parameters> -->
+ <!-- </check> -->
+ <!-- <check level="error" class="org.scalastyle.scalariform.NumberOfMethodsInTypeChecker" enabled="true"> -->
+ <!--  <parameters> -->
+ <!--   <parameter name="maxMethods"><![CDATA[30]]></parameter> -->
+ <!--  </parameters> -->
+ <!-- </check> -->
+ <!-- <check level="error" class="org.scalastyle.scalariform.PublicMethodsHaveTypeChecker" enabled="true"></check> -->
+ <check level="error" class="org.scalastyle.file.NewLineAtEofChecker" enabled="true"></check>
+ <check level="error" class="org.scalastyle.file.NoNewLineAtEofChecker" enabled="false"></check>
+</scalastyle>