Remove redundant sync & callback based applys

azure-client-runtime/src/main/java/com/microsoft/azure/TaskGroup.java

@@ -47,15 +47,6 @@ public interface TaskGroup<T, U extends TaskItem<T>> {
      */
     void prepare();
 
-    /**
-     * Executes the tasks in the group.
-     * <p>
-     * the order of execution of tasks ensure that a task gets selected for execution only after
-     * the execution of all the tasks it depends on
-     * @throws Exception the exception
-     */
-    void execute() throws Exception;
-
     /**
      * Executes the tasks in the group asynchronously.
      *

azure-client-runtime/src/main/java/com/microsoft/azure/TaskGroupBase.java

@@ -58,31 +58,8 @@ public void prepare() {
         }
     }
 
-    @Override
-    public void execute() throws Exception {
-        DAGNode<U> nextNode = dag.getNext();
-        while (nextNode != null) {
-            nextNode.data().execute();
-            this.dag().reportedCompleted(nextNode);
-            nextNode = dag.getNext();
-        }
-    }
-
     @Override
     public Observable<T> executeAsync() {
-        return executeReadyTasksAsync().last();
-    }
-
-    @Override
-    public T taskResult(String taskId) {
-        return dag.getNodeData(taskId).result();
-    }
-
-    /**
-     * Executes all runnable tasks, a task is runnable when all the tasks its depends
-     * on are finished running.
-     */
-    private Observable<T> executeReadyTasksAsync() {
         DAGNode<U> nextNode = dag.getNext();
         final List<Observable<T>> observables = new ArrayList<>();
         while (nextNode != null) {
@@ -95,12 +72,17 @@ public Observable<T> call(T t) {
                             if (dag().isRootNode(thisNode)) {
                                 return Observable.just(t);
                             } else {
-                                return executeReadyTasksAsync();
+                                return executeAsync();
                             }
                         }
                     }));
             nextNode = dag.getNext();
         }
         return Observable.merge(observables);
     }
+
+    @Override
+    public T taskResult(String taskId) {
+        return dag.getNodeData(taskId).result();
+    }
 }

azure-client-runtime/src/main/java/com/microsoft/azure/TaskItem.java

@@ -20,15 +20,6 @@ public interface TaskItem<U> {
      */
     U result();
 
-    /**
-     * Executes the task.
-     * <p>
-     * once executed the result will be available through result getter
-     *
-     * @throws Exception exception
-     */
-    void execute() throws Exception;
-
     /**
      * Executes the task asynchronously.
      * <p>