new helper object to serialize the models to pmml format

mllib/src/main/scala/org/apache/spark/mllib/export/ModelExporter.scala

@@ -0,0 +1,45 @@
+/*
+ * 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.
+ */
+
+package org.apache.spark.mllib.export
+
+import java.io.File
+import javax.xml.transform.stream.StreamResult
+
+import org.jpmml.model.JAXBUtil
+
+import org.apache.spark.mllib.export.pmml.PMMLModelExport
+
+object ModelExporter {
+
+  /**
+  * Export the input model to the stream result in PMML format 
+  */
+  def toPMML(inputModel: Any, streamResult: StreamResult): Unit = {
+    val modelExport = ModelExportFactory.createModelExport(inputModel, ModelExportType.PMML)
+    val pmml = modelExport.asInstanceOf[PMMLModelExport].getPmml()
+    JAXBUtil.marshalPMML(pmml, streamResult)
+  }
+
+  /**
+  * Export the input model to a local path in PMML format 
+  */
+  def toPMML(inputModel: Any, localPath: String): Unit = {
+    toPMML(inputModel, new StreamResult(new File(localPath)))
+  }
+
+}