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https://github.com/uber/cadence-java-samples


https://github.com/uber/cadence-java-samples

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# Java Cadence Samples

These samples demonstrate various capabilities of Java Cadence client and server. You can learn more about Cadence at:

* [Cadence Service](https://github.com/uber/cadence)

* [Cadence Java Client](https://github.com/uber/cadence-java-client)

* [Go Cadence Client](https://github.com/uber-go/cadence-client)



## Overview of the Samples



* **HelloWorld Samples**



    The following samples demonstrate:



  * **HelloActivity**: a single activity workflow

  * **HelloActivityRetry**: how to retry an activity

  * **HelloAsync**: how to call activities asynchronously and wait for them using Promises

  * **HelloAsyncLambda**: how to run part of a workflow asynchronously in a separate task (thread)

  * **HelloAsyncActivityCompletion**: an asynchronous activity implementation

  * **HelloChild**: a child workflow

  * **HelloException**: exception propagation and wrapping

  * **HelloQuery**: a query

  * **HelloSignal**: sending and handling a signal

  * **HelloPeriodic**: a sample workflow that executes an activity periodically forever

  * **HelloSearchAttributes**: how to use search attributes

  * **HelloCron**: a cron workflow 



* **FileProcessing** demonstrates task routing features. The sample workflow downloads a file, processes it, and uploads

    the result to a destination. The first activity can be picked up by any worker. However, the second and third activities

    must be executed on the same host as the first one.



## Get the Samples



Run the following commands:



      git clone https://github.com/uber/cadence-java-samples

      cd cadence-java-samples



## Import into IntelliJ



In the IntelliJ user interface, navigate to **File**->**New**->**Project from Existing Sources**.



Select the cloned directory. In the **Import Project page**, select **Import project from external model**,

choose **Gradle** and then click **Next**->**Finish**.



## Build the Samples



      ./gradlew build



## Run Cadence Server



Run Cadence Server using Docker Compose:



    curl -O https://raw.githubusercontent.com/uber/cadence/master/docker/docker-compose.yml

    docker-compose up



If this does not work, see the instructions for running Cadence Server

at https://github.com/uber/cadence/blob/master/README.md.



## Register the Domain



To register the *samples-domain* domain, run the following command once before running any samples:



    ./gradlew -q execute -PmainClass=com.uber.cadence.samples.common.RegisterDomain



Or using Cadence CLI:



```

cadence --domain samples-domain domain register

```



## See Cadence UI



The Cadence Server running in a docker container includes a Web UI.



Connect to [http://localhost:8088](http://localhost:8088).



Enter the *samples-domain* domain. You'll see a "No Results" page. After running any sample, change the filter in the

top right corner from "Open" to "Closed" to see the list of the completed workflows.



Click on a *RUN ID* of a workflow to see more details about it. Try different view formats to get a different level of

details about the execution history.



## Install Cadence CLI



[Command Line Interface Documentation](https://mfateev.github.io/cadence/docs/08_cli)



## Run the samples



Each sample has specific requirements for running it. The following sections contain information about

how to run each of the samples after you've built them using the preceding instructions.



Don't forget to check unit tests found under src/test/java!



### Hello World



To run the hello world samples:



    ./gradlew -q execute -PmainClass=com.uber.cadence.samples.hello.HelloActivity

    ./gradlew -q execute -PmainClass=com.uber.cadence.samples.hello.HelloActivityRetry

    ./gradlew -q execute -PmainClass=com.uber.cadence.samples.hello.HelloAsync

    ./gradlew -q execute -PmainClass=com.uber.cadence.samples.hello.HelloAsyncActivityCompletion

    ./gradlew -q execute -PmainClass=com.uber.cadence.samples.hello.HelloAsyncLambda

    ./gradlew -q execute -PmainClass=com.uber.cadence.samples.hello.HelloChild

    ./gradlew -q execute -PmainClass=com.uber.cadence.samples.hello.HelloException

    ./gradlew -q execute -PmainClass=com.uber.cadence.samples.hello.HelloPeriodic

    ./gradlew -q execute -PmainClass=com.uber.cadence.samples.hello.HelloQuery

    ./gradlew -q execute -PmainClass=com.uber.cadence.samples.hello.HelloSignal

    ./gradlew -q execute -PmainClass=com.uber.cadence.samples.hello.HelloSearchAttributes

    ./gradlew -q execute -PmainClass=com.uber.cadence.samples.hello.HelloCron



### File Processing



This sample has two executables. Execute each command in a separate terminal window. The first command

runs the worker that hosts the workflow and activities implementation. To demonstrate that activities

execute together, we recommend that you run more than one instance of this worker.



    ./gradlew -q execute -PmainClass=com.uber.cadence.samples.fileprocessing.FileProcessingWorker



The second command starts workflows. Each invocation starts a new workflow execution.



    ./gradlew -q execute -PmainClass=com.uber.cadence.samples.fileprocessing.FileProcessingStarter

    

### Trip Booking



Cadence implementation of the [Camunda BPMN trip booking example](https://github.com/berndruecker/trip-booking-saga-java)



Demonstrates Cadence approach to SAGA.



To run:



    ./gradlew -q execute -PmainClass=com.uber.cadence.samples.bookingsaga.TripBookingSaga



### Sprint Boot Application



Example of how to start a cadence worker service using Spring Boot Framework



To run:



    # Start Cadence Server

    # see https://github.com/uber/cadence/tree/master/docker

    # register domain

    ./gradlew -q execute -PmainClass=com.uber.cadence.samples.common.RegisterDomain

    ./gradlew -q execute -PmainClass=com.uber.cadence.samples.spring.CadenceSamplesApplication