use ParamValidators

Author: mgaido91

mllib/src/main/scala/org/apache/spark/ml/feature/Bucketizer.scala

@@ -140,13 +140,12 @@ final class Bucketizer @Since("1.4.0") (@Since("1.4.0") override val uid: String
    * by `inputCol`. An exception will be thrown if both are set.
    */
   private[feature] def isBucketizeMultipleColumns(): Boolean = {
-    inputColsSanityCheck()
-    outputColsSanityCheck()
+    ParamValidators.assertColOrCols(this)
     if (isSet(inputCol) && isSet(splitsArray)) {
-      raiseIncompatibleParamsException("inputCol", "splitsArray")
+      ParamValidators.raiseIncompatibleParamsException("inputCol", "splitsArray")
     }
     if (isSet(inputCols) && isSet(splits)) {
-      raiseIncompatibleParamsException("inputCols", "splits")
+      ParamValidators.raiseIncompatibleParamsException("inputCols", "splits")
     }
     isSet(inputCols)
   }

mllib/src/main/scala/org/apache/spark/ml/param/params.scala

@@ -31,6 +31,7 @@ import org.json4s.jackson.JsonMethods._
 import org.apache.spark.SparkException
 import org.apache.spark.annotation.{DeveloperApi, Since}
 import org.apache.spark.ml.linalg.{JsonMatrixConverter, JsonVectorConverter, Matrix, Vector}
+import org.apache.spark.ml.param.shared._
 import org.apache.spark.ml.util.Identifiable
 
 /**
@@ -249,6 +250,29 @@ object ParamValidators {
   def arrayLengthGt[T](lowerBound: Double): Array[T] => Boolean = { (value: Array[T]) =>
     value.length > lowerBound
   }
+
+  /**
+   * Checks that either inputCols and outputCols are set or inputCol and outputCol are set. If
+   * this is not true, an `IllegalArgumentException` is raised.
+   * @param model
+   */
+  def assertColOrCols(model: Params): Unit = {
+    model match {
+      case m: HasInputCols with HasInputCol if m.isSet(m.inputCols) && m.isSet(m.inputCol) =>
+        raiseIncompatibleParamsException("inputCols", "inputCol")
+      case m: HasOutputCols with HasInputCol if m.isSet(m.outputCols) && m.isSet(m.inputCol) =>
+        raiseIncompatibleParamsException("outputCols", "inputCol")
+      case m: HasInputCols with HasOutputCol if m.isSet(m.inputCols) && m.isSet(m.outputCol) =>
+        raiseIncompatibleParamsException("inputCols", "outputCol")
+      case m: HasOutputCols with HasOutputCol if m.isSet(m.outputCols) && m.isSet(m.outputCol) =>
+        raiseIncompatibleParamsException("outputCols", "outputCol")
+      case _ =>
+    }
+  }
+
+  def raiseIncompatibleParamsException(paramName1: String, paramName2: String): Unit = {
+    throw new IllegalArgumentException(s"Both `$paramName1` and `$paramName2` are set.")
+  }
 }
 
 // specialize primitive-typed params because Java doesn't recognize scala.Double, scala.Int, ...
@@ -834,14 +858,6 @@ trait Params extends Identifiable with Serializable {
     }
     to
   }
-
-  protected def raiseIncompatibleParamsException(paramName1: String, paramName2: String): Unit = {
-    throw new IllegalArgumentException(
-      s"""
-         |Both `$paramName1` and `$paramName2` are set, `${this.getClass.getName}` only supports
-         |setting either `$paramName1` or `$paramName2`.
-          """.stripMargin)
-  }
 }
 
 /**

mllib/src/main/scala/org/apache/spark/ml/param/shared/sharedParams.scala

@@ -236,16 +236,6 @@ trait HasInputCols extends Params {
 
   /** @group getParam */
   final def getInputCols: Array[String] = $(inputCols)
-
-  final def inputColsSanityCheck(): Unit = {
-    this match {
-      case model: HasInputCol if isSet(inputCols) && isSet(model.inputCol) =>
-        raiseIncompatibleParamsException("inputCols", "inputCol")
-      case model: HasOutputCol if isSet(inputCols) && isSet(model.outputCol) =>
-        raiseIncompatibleParamsException("inputCols", "outputCol")
-      case _ =>
-    }
-  }
 }
 
 /**
@@ -282,16 +272,6 @@ trait HasOutputCols extends Params {
 
   /** @group getParam */
   final def getOutputCols: Array[String] = $(outputCols)
-
-  final def outputColsSanityCheck(): Unit = {
-    this match {
-      case model: HasInputCol if isSet(outputCols) && isSet(model.inputCol) =>
-        raiseIncompatibleParamsException("outputCols", "inputCol")
-      case model: HasOutputCol if isSet(outputCols) && isSet(model.outputCol) =>
-        raiseIncompatibleParamsException("outputCols", "outputCol")
-      case _ =>
-    }
-  }
 }
 
 /**