[SPARK-5549] Define TaskContext interface in Scala.

So the interface documentation shows up in ScalaDoc.

Author: Reynold Xin <rxin@databricks.com>

Closes #4324 from rxin/TaskContext-scala and squashes the following commits:

2480a17 [Reynold Xin] comment
573756f [Reynold Xin] style fixes and javadoc fixes.
87dd537 [Reynold Xin] [SPARK-5549] Define TaskContext interface in Scala.

2 files changed, 43 insertions, 1 deletions

diff --git a/core/src/test/java/org/apache/spark/util/JavaTaskCompletionListenerImpl.java b/core/src/test/java/test/org/apache/spark/JavaTaskCompletionListenerImpl.java
index e9ec700e32..e38bc38949 100644
--- a/core/src/test/java/org/apache/spark/util/JavaTaskCompletionListenerImpl.java
+++ b/core/src/test/java/test/org/apache/spark/JavaTaskCompletionListenerImpl.java
@@ -15,9 +15,10 @@
  * limitations under the License.
  */
 
-package org.apache.spark.util;
+package test.org.apache.spark;
 
 import org.apache.spark.TaskContext;
+import org.apache.spark.util.TaskCompletionListener;
 
 
 /**
diff --git a/core/src/test/java/test/org/apache/spark/JavaTaskContextCompileCheck.java b/core/src/test/java/test/org/apache/spark/JavaTaskContextCompileCheck.java
new file mode 100644
index 0000000000..4a918f725d
--- /dev/null
+++ b/core/src/test/java/test/org/apache/spark/JavaTaskContextCompileCheck.java
@@ -0,0 +1,41 @@
+/*
+ * 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 test.org.apache.spark;
+
+import org.apache.spark.TaskContext;
+
+/**
+ * Something to make sure that TaskContext can be used in Java.
+ */
+public class JavaTaskContextCompileCheck {
+
+  public static void test() {
+    TaskContext tc = TaskContext.get();
+
+    tc.isCompleted();
+    tc.isInterrupted();
+    tc.isRunningLocally();
+
+    tc.addTaskCompletionListener(new JavaTaskCompletionListenerImpl());
+
+    tc.attemptNumber();
+    tc.partitionId();
+    tc.stageId();
+    tc.taskAttemptId();
+  }
+}