# shopping-cart: EJB Stateful Session Bean (SFSB) Example

Serge Pagop

> The `shopping-cart` quickstart demonstrates how to deploy and run a simple Java EE 7 shopping cart application that uses a stateful session bean (SFSB).

## What is it?

The `shopping-cart` quickstart demonstrates how to deploy and run a simple Java EE 7 application that uses a stateful session bean (SFSB) in WildFly Application Server. The application allows customers to buy, checkout, and view their cart contents.

The `shopping-cart` application consists of the following:

1. A server side component:

   This standalone Java EE module is a JAR containing EJBs. It is responsible for managing the shopping cart.

2. A Java client:

   This simple Java client is launched using a `main` method. The remote client looks up a reference to the server module’s API, via JNDI. It then uses this API to perform the operations the customer requests.

## System Requirements

The application this project produces is designed to be run on WildFly Application Server 12 or later.

All you need to build this project is Java 8.0 (Java SDK 1.8) or later and Maven 3.3.1 or later. See Configure Maven to Build and Deploy the Quickstarts to make sure you are configured correctly for testing the quickstarts.

To run these quickstarts with the provided build scripts, you need the WildFly distribution ZIP. For information on how to install and run the WildFly server, see the Getting Started Guide for JBoss Enterprise Application Platform Continuous Delivery located on the Red Hat Customer Portal.

## Use of WILDFLY_HOME

In the following instructions, replace `WILDFLY_HOME` with the actual path to your WildFly installation. The installation path is described in detail here: Use of WILDFLY_HOME and JBOSS_HOME Variables.

## Back Up the WildFly Standalone Server Configuration

Before you begin, back up your server configuration file.

1. If it is running, stop the WildFly server.

2. Back up the `WILDFLY_HOME/standalone/configuration/standalone.xml` file.

After you have completed testing this quickstart, you can replace this file to restore the server to its original configuration.

## Start the WildFly Standalone Server

1. Open a terminal and navigate to the root of the WildFly directory.

2. Start the WildFly server with the default profile by typing the following command.

       $ WILDFLY_HOME/bin/standalone.sh

   Note | For Windows, use the `WILDFLY_HOME\bin\standalone.bat` script.

## Configure the Server

This example quickstart purposely throws a `NoSuchEJBException` exception when the shopping cart is empty. This is the expected result because method is annotated with `@Remove`. This means the next invocation after the shopping cart checkout fails because the container has destroyed the instance and it is no longer available. If you do not run this script, you see the following ERROR in the server log, followed by the stacktrace

    ERROR [org.jboss.as.ejb3.invocation] (EJB default - 7) WFLYEJB0034: EJB Invocation failed on component ShoppingCartBean for method public abstract java.util.Map org.jboss.as.quickstarts.sfsb.ShoppingCart.getCartContents(): javax.ejb.NoSuchEJBException: WFLYEJB0168: Could not find EJB with id UnknownSessionID [5168576665505352655054705267485457555457535250485552546568575254]

Follow the steps below to suppress system exception logging.

1. Before you begin, make sure you do the following:

   - Back up the WildFly standalone server configuration as described above.

   - Start the WildFly server with the standalone default profile as described above.

2. Review the `configure-system-exception.cli` file in the root of this quickstart directory. This script sets the `log-system-exceptions` attribute to `false` in the `ejb3` subsystem in the server configuration file.

3. Open a new terminal, navigate to the root directory of this quickstart, and run the following command, replacing WILDFLY_HOME with the path to your server:

       $ WILDFLY_HOME/bin/jboss-cli.sh --connect --file=configure-system-exception.cli

   Note | For Windows, use the `WILDFLY_HOME\bin\jboss-cli.bat` script.

   You should see the following result when you run the script:

       The batch executed successfully

4. Stop the WildFly server.

## Review the Modified Server Configuration

After stopping the server, open the `WILDFLY_HOME/standalone/configuration/standalone.xml` file and review the changes.

You should see the following configuration in the `ejb3` subsystem.

    <log-system-exceptions value="false"/>

## Install the Quickstart Parent Artifact in Maven

This quickstart requires the `quickstart-parent` artifact to be installed in your local Maven repository. To install it, navigate to your QUICKSTART_HOME directory directory and run the following command.

    $ cd QUICKSTART_HOME
    $ mvn clean install

## Build and Deploy the Quickstart

1. Make sure you start the WildFly server as described above.

2. Open a terminal and navigate to the root directory of this quickstart.

3. Type the following command to build the artifacts.

       $ mvn clean install wildfly:deploy

This deploys the `shopping-cart/server/target/shopping-cart.jar` to the running instance of the server.

You should see a message in the server log indicating that the archive deployed successfully.

You can also check the server console to see information messages regarding the deployment.

    INFO  [org.jboss.as.ejb3.deployment] (MSC service thread 1-2) WFLYEJB0473: JNDI bindings for session bean named 'ShoppingCartBean' in deployment unit 'deployment "{artifactId}-server.jar"' are as follows:

      java:global/{artifactId}-server/ShoppingCartBean!org.jboss.as.quickstarts.sfsb.ShoppingCart
      java:app/{artifactId}-server/ShoppingCartBean!org.jboss.as.quickstarts.sfsb.ShoppingCart
      java:module/ShoppingCartBean!org.jboss.as.quickstarts.sfsb.ShoppingCart
      java:jboss/exported/{artifactId}-server/ShoppingCartBean!org.jboss.as.quickstarts.sfsb.ShoppingCart
      java:global/{artifactId}-server/ShoppingCartBean
      java:app/{artifactId}-server/ShoppingCartBean
      java:module/ShoppingCartBean

    INFO  [org.jboss.weld.deployer] (MSC service thread 1-4) WFLYWELD0006: Starting Services for CDI deployment: {artifactId}-server.jar
    INFO  [org.jboss.weld.deployer] (MSC service thread 1-8) WFLYWELD0009: Starting weld service for deployment {artifactId}-server.jar
    INFO  [org.jboss.as.server] (management-handler-thread - 3) WFLYSRV0010: Deployed "{artifactId}-server.jar" (runtime-name : "{artifactId}-server.jar")

## Run the Client Application

Now start a client that will access the beans you just deployed.

You can use the terminal from the previous step or open a new one and navigate to the root of the `shopping-cart` quickstart directory.

Type the following command:

    $ mvn exec:java -f client/pom.xml

## Investigate the Console Output

You should see the following:

1. The client sends a remote method invocation to the stateful session bean to buy two `32 GB USB 2.0 Flash Drive` and one `Wireless Ergonomic Keyboard and Mouse`.

2. The client sends a remote method invocation to get the contents of the cart and prints it to the console.

3. The client sends a remote method invocation to invoke checkout. Note the `checkout()` method in the server `ShoppingCartBean` has the `@Remove` annotation. This means the container will destroy shopping cart after the call and it will no longer be available.

4. The client calls `getCartContents()` to make sure the shopping cart was removed after checkout. This results in a `javax.ejb.NoSuchEJBException` trace in the server, proving the cart was removed.

5. On the client console, you should see output similar to:

       &&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&
       Obtained the remote interface to the shopping cart
       Buying a "32 GB USB 2.0 Flash Drive".
       Buying another "32 GB USB 2.0 Flash Drive".
       Buying a "Wireless Ergonomic Keyboard and Mouse"

       Print cart:
       1     Wireless Ergonomic Keyboard and Mouse
       2     32 GB USB 2.0 Flash Drive

       Checkout
       Cart was correctly removed, as expected, after Checkout
       &&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&

6. In the server log, you should see:

       INFO  [stdout] (pool-9-thread-8) implementing checkout() left as exercise for the reader!

## Undeploy the Quickstart

When you are finished testing the quickstart, follow these steps to undeploy the archive.

1. Make sure you start the WildFly server as described above.

2. Open a terminal and navigate to the root directory of this quickstart.

3. Type this command to undeploy the archive:

       $ mvn wildfly:undeploy

## Restore the WildFly Standalone Server Configuration

You can restore the original server configuration using either of the following methods.

- You can run the `restore-system-exception.cli` script provided in the root directory of this quickstart.

- You can manually restore the configuration using the backup copy of the configuration file.

### Restore the WildFly Standalone Server Configuration by Running the JBoss CLI Script

1. Start the WildFly server as described above.

2. Open a new terminal, navigate to the root directory of this quickstart, and run the following command, replacing `WILDFLY_HOME` with the path to your server:

       $ WILDFLY_HOME/bin/jboss-cli.sh --connect --file=restore-system-exception.cli

   Note | For Windows, use the `WILDFLY_HOME\bin\jboss-cli.bat` script.

This script restores the the `log-system-exceptions` attribute value to `true`. You should see the following result when you run the script:

+

    The batch executed successfully

### Restore the WildFly Standalone Server Configuration Manually

When you have completed testing the quickstart, you can restore the original server configuration by manually restoring the backup copy the configuration file.

1. If it is running, stop the WildFly server.

2. Replace the `WILDFLY_HOME/standalone/configuration/standalone.xml` file with the backup copy of the file.

## Run the Quickstart in Red Hat JBoss Developer Studio or Eclipse

You can also start the server and deploy the quickstarts or run the Arquillian tests in Red Hat JBoss Developer Studio or from Eclipse using JBoss tools. For general information about how to import a quickstart, add a WildFly server, and build and deploy a quickstart, see Use JBoss Developer Studio or Eclipse to Run the Quickstarts.

This quickstart consists of multiple projects, so it deploys and runs differently in JBoss Developer Studio than the other quickstarts.

- Make sure you configure WildFly to suppress system exception logging as described above under Configure the Server. Stop the server at the end of that step.

- To deploy the server project, right-click on the shopping-cart-server project and choose Run As –> Run on Server.

- To run the client, right-click on the shopping-cart-client project and choose Run As –> Java Application. In the Select Java Application window, choose Client - org.jboss.as.quickstarts.client and click OK. The client output displays in the Console window.

- To undeploy the project, right-click on the shopping-cart-server project and choose Run As –> Maven build. Enter `wildfly:undeploy` for the Goals and click Run.

- Make sure you restore the WildFly standalone server configuration when you have completed testing this quickstart.

## Debug the Application

If you want to debug the source code of any library in the project, run the following command to pull the source into your local repository. The IDE should then detect it.

    $ mvn dependency:sources