Github user myui commented on a diff in the pull request:
https://github.com/apache/incubator-hivemall/pull/116#discussion_r141546522
--- Diff: core/src/main/java/hivemall/embedding/AliasTableBuilderUDTF.java
---
@@ -0,0 +1,203 @@
+/*
+ * 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 hivemall.embedding;
+
+import hivemall.utils.collections.maps.Int2FloatOpenHashTable;
+import hivemall.utils.collections.maps.Int2IntOpenHashTable;
+import hivemall.utils.hadoop.HiveUtils;
+
+import java.util.List;
+import java.util.ArrayList;
+import java.util.Map;
+import java.util.Queue;
+import java.util.ArrayDeque;
+
+import org.apache.hadoop.hive.ql.exec.UDFArgumentException;
+import org.apache.hadoop.hive.ql.metadata.HiveException;
+import org.apache.hadoop.hive.ql.udf.generic.GenericUDTF;
+import org.apache.hadoop.hive.serde2.objectinspector.MapObjectInspector;
+import
org.apache.hadoop.hive.serde2.objectinspector.PrimitiveObjectInspector;
+import org.apache.hadoop.hive.serde2.objectinspector.StructObjectInspector;
+import org.apache.hadoop.hive.serde2.objectinspector.ObjectInspector;
+import
org.apache.hadoop.hive.serde2.objectinspector.ObjectInspectorFactory;
+import
org.apache.hadoop.hive.serde2.objectinspector.primitive.PrimitiveObjectInspectorFactory;
+import
org.apache.hadoop.hive.serde2.objectinspector.primitive.PrimitiveObjectInspectorUtils;
+import org.apache.hadoop.io.FloatWritable;
+import org.apache.hadoop.io.IntWritable;
+import org.apache.hadoop.io.Text;
+
+import javax.annotation.Nonnull;
+
+public final class AliasTableBuilderUDTF extends GenericUDTF {
--- End diff --
Add Javadoc comment for the class referring papers.
```
<pre>
- A. J. Walker, New Fast Method for Generating Discrete Random Numbers with
Arbitrary Frequency Distributions, in Electronics Letters 10, no. 8, pp.
127-128, 1974.
- A. J. Walker, An Efficient Method for Generating Discrete Random
Variables with General Distributions. ACM Transactions on Mathematical Software
3, no. 3, pp. 253-256, 1977.
</pre>
```
---
