15 Roo by example—the Pizza Shop

Roo performs client-side validation against your entities. We discuss this in detail in chapter 3. Enter a few choices, perhaps Brie, Sauce, Mushrooms, and Swiss Chard (Swiss Chard?). Each time you save a choice, you’ll see something like figure 1.5, a confirmation of the saved results as a separate page.

Figure 1.5 The save/edit confirmation page

Clicking the edit icon (the page with the pencil) will take you to a page similar to the creation form, except that it’s working with an already persisted entity.

Finally, if you click the List all Toppings menu item, you’ll see a list of the toppings you’ve already entered, as shown in figure 1.6.

Figure 1.6 The listing page, complete with pagination

As you see in figure 1.6, Roo provides paging support. It also enables viewing, editing, and removing of entities using icons on each row, as well as creating a new one using the new page icon to the left of the list results paging control at the bottom.

1.3.4 Creating a pizza form—dependencies

Let’s look at a slightly more complicated form—the pizza form. Each pizza is com­

prised of a base and one or more toppings. You need to be able to create your pizza and choose your toppings and base from the ones entered before.

Click on the Create new Pizza link. You’ll see the form in figure 1.7.

Figure 1.7 Creating a new pizza

Roo automatically creates the multiselect list for Toppings, and a single-item select list for the Base. The shell has the ability to watch your entities, detect relationships, and automatically update your web forms and controllers with widgets to pick from your related entities.

Try clicking through the application. Start with bases and toppings; create your perfect pizza components. Create some pizzas based on those bases and toppings, and finally, experiment with placing an order. You’ll see the Roo client-side validations for invalid data, drop-down lists of related data, and if you take enough time to enter a lot of data, paging support. And all of this within 49 lines of Roo script code—not a single user-defined line of code.

1.3.5 JSON-based web services with the Pizza Shop

Spring Roo even configures your controllers to support JSON-based web service calls.

If you’re on a Unix/Mac machine, and have installed the Unix curl command-line tool, the script even documents several curl commands you can use to test the web ser­

vice side of this application. For example, to create a Thin Crust base, you’d issue a POST call to the pizzashop/bases URL, passing it JSON data, as shown next:

curl -i -X POST -H "Content-Type: application/json" ➥

-H "Accept: application/json" -d '{name: "Thin Crust"}' ➥

http://localhost:8080/pizzashop/bases

BOOK CONVENTION: THE LINE ARROWS FOR LONG LINES Just as Roo creates long class and package names, Roo and operating system example commands are equally sprawling. Whenever you see the line arrow icon don’t hit Return; just keep typing. This is in contrast to the Unix OS line continuation character, \, which can be typed.

Note the data sent in JSON format to create a new pizza base named Thin Crust; it was JSON data. Curl will respond with the result of the web service call, which is an HTTP 201 response code:

HTTP/1.1 201 Created ...

If you open the web application and review the listing of pizza bases, you’ll now see the Thin Crust base appear.

To fetch a list of pizza bases, you’d just issue a GET call to the pizzashop/bases URL:

curl -i -H "Accept: application/json" ➥

http://localhost:8080/pizzashop/bases

Roo happily responds with the JSON data:

HTTP/1.1 200 OK ...

[{"id":1,"name":"Deep Dish","version":1}, {"id":2, "name":"Whole Wheat","version":1}, {"id":3,"name":"Thin Crust","version":1}]

There! Easy RESTful web service integration.

Roo by example—the Pizza Shop 17

1.3.6 Wrapping up the walk-through

Practice creating a few toppings, bases, pizzas‚ and orders. Remove something and see how Roo asks for a confirmation. Get used to the user interface. You get these features for free, all by asking Roo to configure Spring MVC and scaffolding your entities.

ROO AND WEB FRAMEWORKS Roo installs the web framework Spring MVC if you request it. But there are a number of web frameworks available to Roo directly, including Spring Web Flow (as part of Spring MVC), Google Web Toolkit, JavaServer Faces (in Roo 1.2), and Vaadin. These are all enabled by various Roo add-ons, some of which are installed with Roo itself.

You aren’t required to use Roo’s preconfigured frameworks. You can inte­

grate with any other framework you want to, including Struts, Stripes, Flex‚ or a pure JavaScript application. But if you wish to install your web framework into a number of Roo-managed applications, you may wish to write your own Roo add-on and share it with your developers or the world.

You can terminate the application at this point. Go to your command window and shut down Jetty by hitting [CTRL]-[C].

I RESTARTED THE WEB APPLICATION. WHERE’S MY DATA? If you run the applica­

tion server again, you may find that the data you entered before is missing.

This is because Roo’s default behavior is to re-create the database on startup.

We discuss how to customize this behavior in chapter 3.

Not bad for just a few lines of Roo script code. Let’s take a few minutes and review the script that created your application.

1.3.7 The Pizza Shop script

The Pizza Shop script file, samples/pizzashop.roo in the Roo installation directory, is approximately 48 lines of scripting text, including comments, but the script does a lot of configuration. Let’s walk through some of the commands in this script and touch on what they do.

CREATING THE PROJECT

First, the script creates a Roo project, defining the Java package structure that Roo will use to store objects that it generates:

roo> project --topLevelPackage com.springsource.pizzashop

At this point in time, Roo just defines the project as a JAR file—nothing yet tells it that you need a web application configuration. Roo is flexible and won’t configure more than it needs to.

DATABASE SETUP

Next, the script configures the database:

roo> jpa setup --provider ECLIPSELINK --database H2_IN_MEMORY

This command does quite a bit of work, setting up your JPA database persistence tier.

We describe the work Roo does in depth in chapter 3.

CREATING JPA ENTITIES

The script then sets up the four JPA entity classes—Base, Topping, Pizza, and Pizza-Order. The entity jpa and field commands comprise the content of most of this script. Here’s an excerpt that installs three entities—Base, Topping, and Pizza—and begins to add fields to each of them. Notice the options, such as --sizeMin and --notNull. We talk about those in chapter 3, as well as the field reference and field set commands, which establish relationships between entities:

roo> entity jpa --class ~.domain.Base --activeRecord false ➥

--testAutomatically

roo> field string --fieldName name --sizeMin 2 --notNull

roo> entity jpa --class ~.domain.Topping --activeRecord false ➥

--testAutomatically

roo> field string --fieldName name --sizeMin 2 --notNull roo> entity jpa --class ~.domain.Pizza --activeRecord false ➥

--testAutomatically

roo> field string --fieldName name --notNull --sizeMin 2 roo> field number --fieldName price --type java.math.BigDecimal roo> field set --fieldName toppings --type ~.domain.Topping roo> field reference --fieldName base --type ~.domain.Base SETTING UP REPOSITORIES

The next script section creates Spring JPA repositories using the Spring Data JPA API. These are the objects that talk to the database in the service-based Spring architecture we discussed earlier:

repository jpa --interface ~.repository.ToppingRepository ➥

--entity ~.domain.Topping

repository jpa --interface ~.repository.BaseRepository ➥

--entity ~.domain.Base CONFIGURING SERVICES

Roo can also expose transactional services using Spring Beans. These services are con­

figured to manipulate the entity passed to them, and will delegate calls to the reposi­

tory methods to find, create, update‚ and delete data:

service --interface ~.service.ToppingService --entity ~.domain.Topping service --interface ~.service.BaseService --entity ~.domain.Base CONFIGURING JSON

The rest of the script concerns the web interface. Roo can optionally expose JSON to the web tier if needed. These commands provide JSON support for the web services we reviewed earlier:

json all --deepSerialize web mvc json setup web mvc json all

19