Added ability to retrieve target name from link to comm registrar

protocol/src/main/scala/com/ibm/spark/comm/CommRegistrar.scala

@@ -134,6 +134,17 @@ class CommRegistrar(
   def getLinks(targetName: String): Seq[v5.UUID] =
     getLinksImpl(targetName)
 
+  /**
+   * Retrieves the target associated with the specified link.
+   *
+   * @param commId The Comm id whose target to look up
+   *
+   * @return Some target name if found, otherwise None
+   */
+  def getTargetFromLink(commId: v5.UUID): Option[String] = {
+    commStorage.getTargetFromCommId(commId)
+  }
+
   /**
    * Retrieves the current links for the current target.
    *

protocol/src/test/scala/com/ibm/spark/comm/CommRegistrarSpec.scala

@@ -162,6 +162,22 @@ class CommRegistrarSpec extends FunSpec with Matchers with MockitoSugar
       }
     }
 
+    describe("#getTargetFromLink") {
+      it("should return Some target name if found") {
+        val expected = TestTargetName
+
+        commRegistrar.register(expected).link(TestCommId)
+
+        val actual = commRegistrar.getTargetFromLink(TestCommId).get
+
+        actual should be (expected)
+      }
+
+      it("should return None if not found") {
+        commRegistrar.getTargetFromLink(TestCommId) should be (None)
+      }
+    }
+
     describe("#getLinks") {
       it("should return a collection of links for the target") {
         commRegistrar.register(TestTargetName).link(TestCommId)