Best Practices: Maven multi-module setup for widgets project

Hi,

I have organized my Vaadin Maven project, which uses add-ons, as follows:

  1. A parent project, which basically just defines two Maven modules.
  2. A widgets project, which specifies the add-ons in a GWT module. GWT compiles the widgets and adds them to a jar file.
  3. The actual project, which uses the maven-dependency-plugin to unpack the jar file from the widgets project (more precisely the VAADIN folder) into the webapp.

The setup is slightly more complicated than with a simple Maven project. However, the obvious advantage is that I need to run GWT very rarely - only if the widget set is updated. What’s more, if I use a single add-on only, the jar file from the widgets project is reusable. Add-on authors could provide this, taking away the pain of using GWT for users, which need their add-on only and nothing else.

What do you think? More details below.

Jochen

The parent POM is really simple:

<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
  <modelVersion>4.0.0</modelVersion>
  <groupId>com.mycompany.projects.vaadindemo</groupId>
  <artifactId>vaadindemo-parent</artifactId>
  <version>0.0.1-SNAPSHOT</version>
  <packaging>pom</packaging>
  <modules>
    <module>vaadindemo-widgets</module>
    <module>vaadindemo</module>
  </modules>
</project>

Here’s the widgets module:

<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
  <modelVersion>4.0.0</modelVersion>
  <parent>
    <groupId>com.mycompany.projects.vaadindemo</groupId>
    <artifactId>vaadindemo-parent</artifactId>
    <version>0.0.1-SNAPSHOT</version>
  </parent>
  <groupId>com.mycompany.projects.vaadindemo</groupId>
  <artifactId>vaadindemo-widgets</artifactId>
  <version>0.0.1-SNAPSHOT</version>
  <packaging>jar</packaging>

  <dependencies>
    <dependency>
      <groupId>com.vaadin</groupId>
      <artifactId>vaadin</artifactId>
      <version>6.5.2</version>
    </dependency>
    <dependency>
      <groupId>com.google.gwt</groupId>
      <artifactId>gwt-user</artifactId>
      <version>2.1.0</version>
      <scope>provided</scope>
    </dependency>
    <!-- Add-ons are following, I take TreeTable as an example. -->
    <dependency>
      <groupId>org.vaadin.addons</groupId>
      <artifactId>vaadin-treetable</artifactId>
      <version>1.1.0</version>
    </dependency>
  </dependencies>

  <build>
    <plugins>
      <plugin>
        <groupId>org.codehaus.mojo</groupId>
        <artifactId>gwt-maven-plugin</artifactId>
        <!-- Version 2.1.0-1 works at least with Vaadin 6.5 -->
        <version>2.1.0-1</version>
        <configuration>
          <webappDirectory>${project.build.outputDirectory}/VAADIN/widgetsets</webappDirectory>
          <extraJvmArgs>-Xmx512M -Xss1024k</extraJvmArgs>
          <runTarget>clean</runTarget>
        </configuration>
        <executions>
          <execution>
            <goals>
              <goal>resources</goal>
              <goal>compile</goal>
            </goals>
          </execution>
        </executions>
      </plugin>
      <!-- Updates Vaadin 6.2+ widgetset definitions based on project dependencies -->
      <plugin>
        <groupId>com.vaadin</groupId>
        <artifactId>vaadin-maven-plugin</artifactId>
        <version>1.0.1</version>
        <executions>
          <execution>
            <goals>
              <goal>update-widgetset</goal>
            </goals>
          </execution>
        </executions>
      </plugin>
    </plugins>
  </build>
</project>

And, finally, here’s the actual project, which replaces use of GWT with the maven-dependency-plugin:

<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
  <modelVersion>4.0.0</modelVersion>
  <parent>
    <groupId>com.mycompany.projects.vaadindemo</groupId>
    <artifactId>vaadindemo-parent</artifactId>
    <version>0.0.1-SNAPSHOT</version>
  </parent>
  <groupId>com.mycompany.projects.vaadindemo</groupId>
  <artifactId>vaadindemo</artifactId>
  <version>0.0.1-SNAPSHOT</version>
  <packaging>war</packaging>

  <dependencies>
    <dependency>
      <groupId>com.mycompany.projects.vaadindemo</groupId>
      <artifactId>vaadindemo-widgets</artifactId>
      <version>0.0.1-SNAPSHOT</version>
    </dependency>
  </dependencies>

  <build>
    <plugins>
      <plugin>
        <groupId>org.apache.maven.plugins</groupId>
        <artifactId>maven-war-plugin</artifactId>
        <version>2.1.1</version>
        <configuration>
          <webappDirectory>${webappDirectory}</webappDirectory>
        </configuration>
      </plugin>
      <plugin>
        <groupId>org.apache.maven.plugins</groupId>
        <artifactId>maven-dependency-plugin</artifactId>
        <version>2.1</version>
        <executions>
          <execution>
            <phase>generate-resources</phase>
            <goals>
              <goal>unpack-dependencies</goal>
            </goals>
            <configuration>
              <outputDirectory>${webappDirectory}</outputDirectory>
              <includeArtifactIds>vaadindemo-widgets</includeArtifactIds>
              <includes>VAADIN/**/*</includes>
            </configuration>
          </execution>
        </executions>
      </plugin>
    </plugins>
  </build>

  <properties>
    <webappDirectory>${project.build.directory}/${project.artifactId}</webappDirectory>
  </properties>
</project>

Hi Jochen.

I tryed to do like your example, but the jar generated by module vaadindemo-widgets doesn’t have the directory VAADIN/widgetsets/… Inside the target directory exists the VAADIN/widgetsets/…

Do you have any idea why the VAADIN/widgetsets/… is not in jar?

Thank you

Are you sure you have

<webappDirectory>${project.build.outputDirectory}/VAADIN/widgetsets</webappDirectory>

and not

<webappDirectory>${project.build.directory}/VAADIN/widgetsets</webappDirectory>

Yes, this is very much like what we are now using for building the Vaadin XS add-on. See the POMs and project structure here:
http://dev.vaadin.com/browser/addons/XS
.