/
HelloActivity.java
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/
HelloActivity.java
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/*
* 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.activity.ActivityInterface;
import io.temporal.activity.ActivityMethod;
import io.temporal.activity.ActivityOptions;
import io.temporal.client.WorkflowClient;
import io.temporal.client.WorkflowOptions;
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;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
/** Sample Temporal Workflow Definition that executes a single Activity. */
public class HelloActivity {
// Define the task queue name
static final String TASK_QUEUE = "HelloActivityTaskQueue";
// Define our workflow unique id
static final String WORKFLOW_ID = "HelloActivityWorkflow";
/**
* 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 GreetingWorkflow {
/**
* This is the method that is executed when the Workflow Execution is started. The Workflow
* Execution completes when this method finishes execution.
*/
@WorkflowMethod
String getGreeting(String name);
}
/**
* This is the Activity Definition's Interface. Activities are building blocks of any Temporal
* Workflow and contain any business logic that could perform long running computation, network
* calls, etc.
*
* <p>Annotating Activity Definition methods with @ActivityMethod is optional.
*
* @see io.temporal.activity.ActivityInterface
* @see io.temporal.activity.ActivityMethod
*/
@ActivityInterface
public interface GreetingActivities {
// Define your activity method which can be called during workflow execution
@ActivityMethod(name = "greet")
String composeGreeting(String greeting, String name);
}
// Define the workflow implementation which implements our getGreeting workflow method.
public static class GreetingWorkflowImpl implements GreetingWorkflow {
/**
* Define the GreetingActivities stub. Activity stubs are proxies for activity invocations that
* are executed outside of the workflow thread on the activity worker, that can be on a
* different host. Temporal is going to dispatch the activity results back to the workflow and
* unblock the stub as soon as activity is completed on the activity worker.
*
* <p>In the {@link ActivityOptions} definition the "setStartToCloseTimeout" option sets the
* overall timeout that our workflow is willing to wait for activity to complete. For this
* example it is set to 2 seconds.
*/
private final GreetingActivities activities =
Workflow.newActivityStub(
GreetingActivities.class,
ActivityOptions.newBuilder().setStartToCloseTimeout(Duration.ofSeconds(2)).build());
@Override
public String getGreeting(String name) {
// This is a blocking call that returns only after the activity has completed.
return activities.composeGreeting("Hello", name);
}
}
/** Simple activity implementation, that concatenates two strings. */
static class GreetingActivitiesImpl implements GreetingActivities {
private static final Logger log = LoggerFactory.getLogger(GreetingActivitiesImpl.class);
@Override
public String composeGreeting(String greeting, String name) {
log.info("Composing greeting...");
return greeting + " " + name + "!";
}
}
/**
* With our Workflow and Activities defined, we can now start execution. The main method starts
* the worker and then the workflow.
*/
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(GreetingWorkflowImpl.class);
/*
* Register our Activity Types with the Worker. Since Activities are stateless and thread-safe,
* the Activity Type is a shared instance.
*/
worker.registerActivitiesImplementations(new GreetingActivitiesImpl());
/*
* Start all the workers registered for a specific task queue.
* The started workers then start polling for workflows and activities.
*/
factory.start();
// Create the workflow client stub. It is used to start our workflow execution.
GreetingWorkflow workflow =
client.newWorkflowStub(
GreetingWorkflow.class,
WorkflowOptions.newBuilder()
.setWorkflowId(WORKFLOW_ID)
.setTaskQueue(TASK_QUEUE)
.build());
/*
* Execute our workflow and wait for it to complete. The call to our getGreeting method is
* synchronous.
*
* See {@link io.temporal.samples.hello.HelloSignal} for an example of starting workflow
* without waiting synchronously for its result.
*/
String greeting = workflow.getGreeting("World");
// Display workflow execution results
System.out.println(greeting);
System.exit(0);
}
}