[SPARK-5228][WebUI] Hide tables for "Active Jobs/Completed Jobs/Failed Jobs" when they are empty

In current WebUI, tables for Active Stages, Completed Stages, Skipped Stages and Failed Stages are hidden when they are empty while tables for Active Jobs, Completed Jobs and Failed Jobs are not hidden though they are empty.

This is before my patch is applied.

![2015-01-13 14 13 03](https://cloud.githubusercontent.com/assets/4736016/5730793/2b73d6f4-9b32-11e4-9a24-1784d758c644.png)

And this is after my patch is applied.

![2015-01-13 14 38 13](https://cloud.githubusercontent.com/assets/4736016/5730797/359ea2da-9b32-11e4-97b0-544739ddbf4c.png)

Author: Kousuke Saruta <sarutak@oss.nttdata.co.jp>

Closes #4028 from sarutak/SPARK-5228 and squashes the following commits:

b1e6e8b [Kousuke Saruta] Fixed a small typo
daab563 [Kousuke Saruta] Merge branch 'master' of git://git.apache.org/spark into SPARK-5228
9493a1d [Kousuke Saruta] Modified AllJobPage.scala so that hide Active Jobs/Completed Jobs/Failed Jobs when they are empty

1 files changed, 43 insertions, 19 deletions

diff --git a/core/src/main/scala/org/apache/spark/ui/jobs/AllJobsPage.scala b/core/src/main/scala/org/apache/spark/ui/jobs/AllJobsPage.scala
index ea2d187a0e..1d1c701878 100644
--- a/core/src/main/scala/org/apache/spark/ui/jobs/AllJobsPage.scala
+++ b/core/src/main/scala/org/apache/spark/ui/jobs/AllJobsPage.scala
@@ -47,7 +47,7 @@ private[ui] class AllJobsPage(parent: JobsTab) extends WebUIPage("") {
       val lastStageData = lastStageInfo.flatMap { s =>
         listener.stageIdToData.get((s.stageId, s.attemptId))
       }
-      val isComplete = job.status == JobExecutionStatus.SUCCEEDED
+
       val lastStageName = lastStageInfo.map(_.name).getOrElse("(Unknown Stage Name)")
       val lastStageDescription = lastStageData.flatMap(_.description).getOrElse("")
       val duration: Option[Long] = {
@@ -107,6 +107,10 @@ private[ui] class AllJobsPage(parent: JobsTab) extends WebUIPage("") {
       val failedJobsTable =
         jobsTable(failedJobs.sortBy(_.endTime.getOrElse(-1L)).reverse)
 
+      val shouldShowActiveJobs = activeJobs.nonEmpty
+      val shouldShowCompletedJobs = completedJobs.nonEmpty
+      val shouldShowFailedJobs = failedJobs.nonEmpty
+
       val summary: NodeSeq =
         <div>
           <ul class="unstyled">
@@ -121,27 +125,47 @@ private[ui] class AllJobsPage(parent: JobsTab) extends WebUIPage("") {
               <strong>Scheduling Mode: </strong>
               {listener.schedulingMode.map(_.toString).getOrElse("Unknown")}
             </li>
-            <li>
-              <a href="#active"><strong>Active Jobs:</strong></a>
-              {activeJobs.size}
-            </li>
-            <li>
-              <a href="#completed"><strong>Completed Jobs:</strong></a>
-              {completedJobs.size}
-            </li>
-            <li>
-              <a href="#failed"><strong>Failed Jobs:</strong></a>
-              {failedJobs.size}
-            </li>
+            {
+              if (shouldShowActiveJobs) {
+                <li>
+                  <a href="#active"><strong>Active Jobs:</strong></a>
+                  {activeJobs.size}
+                </li>
+              }
+            }
+            {
+              if (shouldShowCompletedJobs) {
+                <li>
+                  <a href="#completed"><strong>Completed Jobs:</strong></a>
+                  {completedJobs.size}
+                </li>
+              }
+            }
+            {
+              if (shouldShowFailedJobs) {
+                <li>
+                  <a href="#failed"><strong>Failed Jobs:</strong></a>
+                  {failedJobs.size}
+                </li>
+              }
+            }
           </ul>
         </div>
 
-      val content = summary ++
-        <h4 id="active">Active Jobs ({activeJobs.size})</h4> ++ activeJobsTable ++
-        <h4 id="completed">Completed Jobs ({completedJobs.size})</h4> ++ completedJobsTable ++
-        <h4 id ="failed">Failed Jobs ({failedJobs.size})</h4> ++ failedJobsTable
-
-      val helpText = """A job is triggered by a action, like "count()" or "saveAsTextFile()".""" +
+      var content = summary
+      if (shouldShowActiveJobs) {
+        content ++= <h4 id="active">Active Jobs ({activeJobs.size})</h4> ++
+          activeJobsTable
+      }
+      if (shouldShowCompletedJobs) {
+        content ++= <h4 id="completed">Completed Jobs ({completedJobs.size})</h4> ++
+          completedJobsTable
+      }
+      if (shouldShowFailedJobs) {
+        content ++= <h4 id ="failed">Failed Jobs ({failedJobs.size})</h4> ++
+          failedJobsTable
+      }
+      val helpText = """A job is triggered by an action, like "count()" or "saveAsTextFile()".""" +
         " Click on a job's title to see information about the stages of tasks associated with" +
         " the job."