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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 spark.mllib.examples;
+
+import spark.api.java.JavaRDD;
+import spark.api.java.JavaSparkContext;
+import spark.api.java.function.Function;
+
+import spark.mllib.recommendation.ALS;
+import spark.mllib.recommendation.MatrixFactorizationModel;
+import spark.mllib.recommendation.Rating;
+
+import java.io.Serializable;
+import java.util.Arrays;
+import java.util.StringTokenizer;
+
+import scala.Tuple2;
+
+/**
+ * Example using MLLib ALS from Java.
+ */
+public class  JavaALS {
+
+  static class ParseRating extends Function<String, Rating> {
+    public Rating call(String line) {
+      StringTokenizer tok = new StringTokenizer(line, ",");
+      int x = Integer.parseInt(tok.nextToken());
+      int y = Integer.parseInt(tok.nextToken());
+      double rating = Double.parseDouble(tok.nextToken());
+      return new Rating(x, y, rating);
+    }
+  }
+
+  static class FeaturesToString extends Function<Tuple2<Object, double[]>, String> {
+    public String call(Tuple2<Object, double[]> element) {
+      return element._1().toString() + "," + Arrays.toString(element._2());
+    }
+  }
+
+  public static void main(String[] args) {
+
+    if (args.length != 5 && args.length != 6) {
+      System.err.println(
+          "Usage: JavaALS <master> <ratings_file> <rank> <iterations> <output_dir> [<blocks>]");
+      System.exit(1);
+    }
+
+    int rank = Integer.parseInt(args[2]);
+    int iterations = Integer.parseInt(args[3]);
+    String outputDir = args[4];
+    int blocks = -1;
+    if (args.length == 6) {
+      blocks = Integer.parseInt(args[5]);
+    }
+
+    JavaSparkContext sc = new JavaSparkContext(args[0], "JavaALS",
+        System.getenv("SPARK_HOME"), System.getenv("SPARK_EXAMPLES_JAR"));
+    JavaRDD<String> lines = sc.textFile(args[1]);
+
+    JavaRDD<Rating> ratings = lines.map(new ParseRating());
+
+    MatrixFactorizationModel model = ALS.train(ratings.rdd(), rank, iterations, 0.01, blocks);
+
+    model.userFeatures().toJavaRDD().map(new FeaturesToString()).saveAsTextFile(
+        outputDir + "/userFeatures");
+    model.productFeatures().toJavaRDD().map(new FeaturesToString()).saveAsTextFile(
+        outputDir + "/productFeatures");
+    System.out.println("Final user/product features written to " + outputDir);
+
+    System.exit(0);
+  }
+}