Revert "apply mesos#845"

This reverts commit cb35b20.

src/main/scala/org/apache/mesos/chronos/scheduler/api/JobManagementResource.scala

@@ -324,7 +324,11 @@ class JobManagementResource @Inject()(val jobScheduler: JobScheduler,
   @Timed
   def getSummary(): Response = {
     try {
-      val jobs = jobGraph.transformVertextSet(j => jobGraph.getJobForName(j))
+      import scala.collection.JavaConversions._
+      val jobs = jobGraph.dag.vertexSet()
+        .flatMap {
+          jobGraph.getJobForName
+        }
         .map {
           job =>
             val state = Exporter.getLastState(job).toString
@@ -364,7 +368,12 @@ class JobManagementResource @Inject()(val jobScheduler: JobScheduler,
              @QueryParam("offset") offset: Integer
             ) = {
     try {
-      val jobs = jobGraph.transformVertextSet(j => jobGraph.getJobForName(j))
+      val jobs = ListBuffer[BaseJob]()
+      import scala.collection.JavaConversions._
+      jobGraph.dag.vertexSet().map({
+        job =>
+          jobs += jobGraph.getJobForName(job).get
+      })
 
       val _limit: Integer = limit match {
         case x: Integer =>

src/main/scala/org/apache/mesos/chronos/scheduler/graph/JobGraph.scala

@@ -12,7 +12,6 @@ import org.jgrapht.graph.DefaultEdge
 import scala.collection.convert.decorateAsScala._
 import scala.collection.mutable.ListBuffer
 import scala.collection.{mutable, _}
-import scala.collection.JavaConverters._
 
 /**
   * This class provides methods to access dependency structures of jobs.
@@ -53,14 +52,6 @@ class JobGraph {
       Some(parents)
   }
 
-
-  def transformVertextSet[T](f: String => Option[T]): Set[T] = {
-    lock.synchronized {
-      dag.vertexSet().asScala.flatMap(vertex => f(vertex))
-    }
-  }
-
-
   def getJobForName(name: String): Option[BaseJob] = {
     jobNameMapping.get(name)
   }