The first thing that you need to do is to create an empty directory in which you are going to create your Roo project. Create a ch01-recipe sub-directory in the C:\roo-cookbbook directory, if you haven't created it yet. Start the Roo shell from the ch01-recipe directory by executing the Roo batch file or shell script, as shown here:

C:\roo-cookbook\ch01-recipe>roo

To create a Roo project, execute the project command from your Roo shell, shown as follows:

roo>project --topLevelPackage sample.roo.flightapp --java 6 --projectName flight-app

Created C:\roo-cookbook\ch01-recipe\pom.xml
.....
Created SRC_MAIN_RESOURCES\META-INF\spring\applicationContext.xml
Created SRC_MAIN_RESOURCES\log4j.properties

sample.roo.flightapp roo>

Notice the change in the Roo prompt after the execution of the project command. The change in prompt indicates that you are now working with a project whose top-level package is sample.roo.flightapp. If you start the Roo shell from a directory, which already contains a Roo project, then the Roo prompt will not change.

The following table describes the purpose of each of the arguments passed to the project command:

Spring Roo distribution comes with a Maven add-on , which is responsible for processing the project command. There are more Roo commands that are processed by the Maven add-on, which you will see later in this book.

The output of project command shows that it creates directories with name SRC_MAIN_JAVA, SCR_MAIN_WEBAPP, and so on. These are logical names given to standard directories created by the Maven add-on. The following table shows the directories to which each of these names map in the case of the flight-app project:

As evident from the execution of the project command, not only did it create a maven-ized project, it also created Spring's applicationContext.xml, maven's pom.xml file, and a log4j.properties file. The following XML code shows the contents of the applicationContext.xml file, which contains some interesting details:

<beans ..>

   <context:property-placeholder 
      location="classpath*:META-INF/spring/*.properties"/>

   <context:spring-configured/>

   <context:component-scan base-package="sample.roo.flightapp">
   <context:exclude-filter 
                  expression=".*_Roo_.*" type="regex"/>
   <context:exclude-filter expression=
      "org.springframework.stereotype.Controller"   
      type="annotation"/>
   </context:component-scan>
</beans>

The important inferences that we can derive from the content of applicationContext.xml are:

The other important artifact that was generated during the project creation is the pom.xml file that is used by maven. The following XML code shows how the argument values specified in the project command are used in creating the pom.xml file of the flight-app project:

<project >
   .....
   <groupId>sample.roo.flightapp</groupId>
   <artifactId>flight-app</artifactId>
   <packaging>jar</packaging>
   <version>0.1.0.BUILD-SNAPSHOT</version>
   <name>flight-app</name>
</project>

You may notice that the value of the <packaging> element is jar and not war. The reason for this lies with the fact that we haven't yet added a web layer to the flight-app application. We will see in Chapter 4, Web Application Development with Spring Web MVC and Chapter 5, Web Application Development with GWT, Flex, and Spring Web Flow how we go about creating a web application using Spring Roo.

The pom.xml additionally contains Maven plugins, which are available to Roo projects by default. The following table summarizes some of the important Maven plugins that are available to our newly created flight-app project:

You won't always be starting a project from scratch, and you may find Spring Roo compelling enough (which you will, as we go through its various features) to use in your existing Spring-based Java projects. In such scenarios, you need to do the following:

There are other things you will need to do to convert your existing projects into a Roo project, which we will discuss in relevant recipes.