[Streaming] Implement streaming job-worker. (#8780)

streaming/java/streaming-api/src/main/java/io/ray/streaming/api/context/StreamingContext.java

@@ -3,9 +3,9 @@ package io.ray.streaming.api.context;
 import com.google.common.base.Preconditions;
 import io.ray.api.Ray;
 import io.ray.streaming.api.stream.StreamSink;
+import io.ray.streaming.client.JobClient;
 import io.ray.streaming.jobgraph.JobGraph;
 import io.ray.streaming.jobgraph.JobGraphBuilder;
-import io.ray.streaming.schedule.JobScheduler;
 import io.ray.streaming.util.Config;
 import java.io.Serializable;
 import java.util.ArrayList;
@@ -74,12 +74,12 @@ public class StreamingContext implements Serializable {
       LOG.info("Reuse existing cluster.");
     }
 
-    ServiceLoader<JobScheduler> serviceLoader = ServiceLoader.load(JobScheduler.class);
-    Iterator<JobScheduler> iterator = serviceLoader.iterator();
+    ServiceLoader<JobClient> serviceLoader = ServiceLoader.load(JobClient.class);
+    Iterator<JobClient> iterator = serviceLoader.iterator();
     Preconditions.checkArgument(iterator.hasNext(),
-        "No JobScheduler implementation has been provided.");
-    JobScheduler jobSchedule = iterator.next();
-    jobSchedule.schedule(jobGraph, jobConfig);
+        "No JobClient implementation has been provided.");
+    JobClient jobClient = iterator.next();
+    jobClient.submit(jobGraph, jobConfig);
   }
 
   public int generateId() {

streaming/java/streaming-api/src/main/java/io/ray/streaming/client/JobClient.java

@@ -0,0 +1,17 @@
+package io.ray.streaming.client;
+
+import io.ray.streaming.jobgraph.JobGraph;
+import java.util.Map;
+
+/**
+ * Interface of the job client.
+ */
+public interface JobClient {
+
+  /**
+   * Submit job with logical plan to run.
+   *
+   * @param jobGraph The logical plan.
+   */
+  void submit(JobGraph jobGraph, Map<String, String> conf);
+}

streaming/java/streaming-api/src/main/java/io/ray/streaming/schedule/JobScheduler.java

@@ -1,18 +0,0 @@
-package io.ray.streaming.schedule;
-
-
-import io.ray.streaming.jobgraph.JobGraph;
-import java.util.Map;
-
-/**
- * Interface of the job scheduler.
- */
-public interface JobScheduler {
-
-  /**
-   * Assign logical plan to physical execution graph, and schedule job to run.
-   *
-   * @param jobGraph The logical plan.
-   */
-  void schedule(JobGraph jobGraph, Map<String, String> conf);
-}