1 files changed, 45 insertions, 0 deletions
diff --git a/mllib/src/main/scala/org/apache/spark/ml/r/RWrappers.scala b/mllib/src/main/scala/org/apache/spark/ml/r/RWrappers.scala
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+++ b/mllib/src/main/scala/org/apache/spark/ml/r/RWrappers.scala
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+/*
+ * 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.ml.r
+
+import org.apache.hadoop.fs.Path
+import org.json4s.DefaultFormats
+import org.json4s.jackson.JsonMethods._
+
+import org.apache.spark.SparkException
+import org.apache.spark.ml.util.MLReader
+
+/**
+ * This is the Scala stub of SparkR ml.load. It will dispatch the call to corresponding
+ * model wrapper loading function according the class name extracted from rMetadata of the path.
+ */
+private[r] object RWrappers extends MLReader[Object] {
+
+  override def load(path: String): Object = {
+    implicit val format = DefaultFormats
+    val rMetadataPath = new Path(path, "rMetadata").toString
+    val rMetadataStr = sc.textFile(rMetadataPath, 1).first()
+    val rMetadata = parse(rMetadataStr)
+    val className = (rMetadata \ "class").extract[String]
+    className match {
+      case "org.apache.spark.ml.r.NaiveBayesWrapper" => NaiveBayesWrapper.load(path)
+      case _ =>
+        throw new SparkException(s"SparkR ml.load does not support load $className")
+    }
+  }
+}