Hello delayed start sample

README.md

@@ -71,6 +71,7 @@ See the README.md file in each main sample directory for cut/paste Gradle comman
     - [**HelloSearchAttributes**](/core/src/main/java/io/temporal/samples/hello/HelloSearchAttributes.java): Demonstrates how to add custom Search Attributes to Workflow Executions.
     - [**HelloSideEffect**](/core/src/main/java/io/temporal/samples/hello/HelloSideEffect.java)**: Demonstrates how to implement a Side Effect.
     - [**HelloUpdate**](/core/src/main/java/io/temporal/samples/hello/HelloUpdate.java): Demonstrates how to create and interact with an Update.
+    - [**HelloDelayedStart**](/core/src/main/java/io/temporal/samples/hello/HelloDelayedStart.java): Demonstrates how to use delayed start config option when starting a Workflow Executions.
 
 
 #### Scenario-based samples

core/src/main/java/io/temporal/samples/hello/HelloDelayedStart.java

@@ -0,0 +1,131 @@
+/*
+ *  Copyright (c) 2020 Temporal Technologies, Inc. All Rights Reserved
+ *
+ *  Copyright 2012-2016 Amazon.com, Inc. or its affiliates. All Rights Reserved.
+ *
+ *  Modifications copyright (C) 2017 Uber Technologies, Inc.
+ *
+ *  Licensed under the Apache License, Version 2.0 (the "License"). You may not
+ *  use this file except in compliance with the License. A copy of the License is
+ *  located at
+ *
+ *  http://aws.amazon.com/apache2.0
+ *
+ *  or in the "license" file accompanying this file. This file is distributed on
+ *  an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either
+ *  express or implied. See the License for the specific language governing
+ *  permissions and limitations under the License.
+ */
+
+package io.temporal.samples.hello;
+
+import io.temporal.client.WorkflowClient;
+import io.temporal.client.WorkflowOptions;
+import io.temporal.common.WorkflowExecutionHistory;
+import io.temporal.serviceclient.WorkflowServiceStubs;
+import io.temporal.worker.Worker;
+import io.temporal.worker.WorkerFactory;
+import io.temporal.workflow.Workflow;
+import io.temporal.workflow.WorkflowInterface;
+import io.temporal.workflow.WorkflowMethod;
+import java.time.Duration;
+
+/** Sample Temporal Workflow Definition that shows how to use delayed start. */
+public class HelloDelayedStart {
+  // Define the task queue name
+  static final String TASK_QUEUE = "HelloDelayedStartTaskQueue";
+
+  // Define our workflow unique id
+  static final String WORKFLOW_ID = "HelloDelayedStartWorkflow";
+
+  /**
+   * The Workflow Definition's Interface must contain one method annotated with @WorkflowMethod.
+   *
+   * <p>Workflow Definitions should not contain any heavyweight computations, non-deterministic
+   * code, network calls, database operations, etc. Those things should be handled by the
+   * Activities.
+   *
+   * @see io.temporal.workflow.WorkflowInterface
+   * @see io.temporal.workflow.WorkflowMethod
+   */
+  @WorkflowInterface
+  public interface DelayedStartWorkflow {
+
+    /**
+     * This is the method that is executed when the Workflow Execution is started. The Workflow
+     * Execution completes when this method finishes execution.
+     */
+    @WorkflowMethod
+    void start();
+  }
+
+  // Define the workflow implementation which implements our start workflow method.
+  public static class DelayedStartWorkflowImpl implements DelayedStartWorkflow {
+    @Override
+    public void start() {
+      // this workflow just sleeps for a second
+      Workflow.sleep(Duration.ofSeconds(1));
+    }
+  }
+
+  public static void main(String[] args) {
+    // Get a Workflow service stub.
+    WorkflowServiceStubs service = WorkflowServiceStubs.newLocalServiceStubs();
+
+    /*
+     * Get a Workflow service client which can be used to start, Signal, and Query Workflow Executions.
+     */
+    WorkflowClient client = WorkflowClient.newInstance(service);
+
+    /*
+     * Define the workflow factory. It is used to create workflow workers for a specific task queue.
+     */
+    WorkerFactory factory = WorkerFactory.newInstance(client);
+
+    /*
+     * Define the workflow worker. Workflow workers listen to a defined task queue and process
+     * workflows and activities.
+     */
+    Worker worker = factory.newWorker(TASK_QUEUE);
+
+    /*
+     * Register our workflow implementation with the worker.
+     * Workflow implementations must be known to the worker at runtime in
+     * order to dispatch workflow tasks.
+     */
+    worker.registerWorkflowImplementationTypes(DelayedStartWorkflowImpl.class);
+
+    /*
+     * Start all the workers registered for a specific task queue.
+     * The started workers then start polling for workflows and activities.
+     */
+    factory.start();
+
+    DelayedStartWorkflow workflow =
+        client.newWorkflowStub(
+            DelayedStartWorkflow.class,
+            WorkflowOptions.newBuilder()
+                .setWorkflowId(WORKFLOW_ID)
+                .setTaskQueue(TASK_QUEUE)
+                // set delayed start in 2 seconds
+                .setStartDelay(Duration.ofSeconds(2))
+                .build());
+
+    workflow.start();
+
+    // Delayed executions are still created right away by the service but
+    // they have a firstWorkflowTaskBackoff set to the delay duration
+    // meaning the first workflow task is dispatched by service
+    // 2 second after exec is started in our sample
+    WorkflowExecutionHistory history = client.fetchHistory(WORKFLOW_ID);
+    com.google.protobuf.Duration backoff =
+        history
+            .getHistory()
+            .getEvents(0)
+            .getWorkflowExecutionStartedEventAttributes()
+            .getFirstWorkflowTaskBackoff();
+    System.out.println("First workflow task backoff: " + backoff.getSeconds());
+
+    System.exit(0);
+  }
+}

core/src/test/java/io/temporal/samples/hello/HelloDelayedStartTest.java

@@ -0,0 +1,69 @@
+/*
+ *  Copyright (c) 2020 Temporal Technologies, Inc. All Rights Reserved
+ *
+ *  Copyright 2012-2016 Amazon.com, Inc. or its affiliates. All Rights Reserved.
+ *
+ *  Modifications copyright (C) 2017 Uber Technologies, Inc.
+ *
+ *  Licensed under the Apache License, Version 2.0 (the "License"). You may not
+ *  use this file except in compliance with the License. A copy of the License is
+ *  located at
+ *
+ *  http://aws.amazon.com/apache2.0
+ *
+ *  or in the "license" file accompanying this file. This file is distributed on
+ *  an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either
+ *  express or implied. See the License for the specific language governing
+ *  permissions and limitations under the License.
+ */
+
+package io.temporal.samples.hello;
+
+import static org.junit.Assert.assertEquals;
+
+import io.temporal.client.WorkflowOptions;
+import io.temporal.common.WorkflowExecutionHistory;
+import io.temporal.testing.TestWorkflowRule;
+import java.time.Duration;
+import org.junit.Rule;
+import org.junit.Test;
+
+public class HelloDelayedStartTest {
+  private final String WORKFLOW_ID = "HelloDelayedStartWorkflow";
+
+  @Rule
+  public TestWorkflowRule testWorkflowRule =
+      TestWorkflowRule.newBuilder()
+          .setWorkflowTypes(HelloDelayedStart.DelayedStartWorkflowImpl.class)
+          .build();
+
+  @Test
+  public void testDelayedStart() {
+    // Get a workflow stub using the same task queue the worker uses.
+    WorkflowOptions workflowOptions =
+        WorkflowOptions.newBuilder()
+            .setTaskQueue(testWorkflowRule.getTaskQueue())
+            .setWorkflowId(WORKFLOW_ID)
+            .setStartDelay(Duration.ofSeconds(2))
+            .build();
+
+    HelloDelayedStart.DelayedStartWorkflow workflow =
+        testWorkflowRule
+            .getWorkflowClient()
+            .newWorkflowStub(HelloDelayedStart.DelayedStartWorkflow.class, workflowOptions);
+
+    workflow.start();
+
+    // Fetch event history and make sure we got the 2 seconds first workflow task backoff
+    WorkflowExecutionHistory history =
+        testWorkflowRule.getWorkflowClient().fetchHistory(WORKFLOW_ID);
+    com.google.protobuf.Duration backoff =
+        history
+            .getHistory()
+            .getEvents(0)
+            .getWorkflowExecutionStartedEventAttributes()
+            .getFirstWorkflowTaskBackoff();
+
+    assertEquals(2, backoff.getSeconds());
+  }
+}