In order to use GWT-Maven, you will need to configure GWT-Maven using the plugin configuration in your POM, and you will need to decide how you want to handle GWT being present (automatic or manual mode - more below).
Regardless of which "mode" you use, automatic, or manual, you also need to configure GWT-Maven itself, of course.
For example:
<plugin>
<groupId>com.totsp.gwt</groupId>
<artifactId>maven-googlewebtoolkit2-plugin</artifactId>
<version>2.0-beta22</version>
<configuration>
<logLevel>INFO</logLevel>
<compileTargets>
<value>com.totsp.sample.Application</value>
</compileTargets>
<runTarget>com.totsp.sample.Application/Application.html</runTarget>
<style>DETAILED</style>
<noServer>false</noServer>
<gwtVersion>1.5.1</gwtVersion>
<extraJvmArgs>-Dgwt.args=-web</extraJvmArgs>
</configuration>
<executions>
<execution>
<goals>
<goal>mergewebxml</goal>
<!--<goal>i18n</goal>-->
<goal>compile</goal>
<goal>gwt</goal>
<!-- <goal>test</goal>-->
</goals>
</execution>
</executions>
</plugin>
Getting the plugin is simple. You just need to add the GWT-Maven pluginRepository to your POM.
<pluginRepositories>
<pluginRepository>
<id>gwt-maven</id>
<url>http://gwt-maven.googlecode.com/svn/trunk/mavenrepo</url>
</pluginRepository>
</pluginRepositories>
The plugin needs to know where to find GWT (jars *and* native libraries). There are two ways you can do this.
If you are going to do automatic setup, you need to include the GWT dependencies in your POM.
For example:
<!-- GWT deps (from central repo) -->
<dependency>
<groupId>com.google.gwt</groupId>
<artifactId>gwt-servlet</artifactId>
<version>${gwtVersion}</version>
<scope>runtime</scope>
</dependency>
<dependency>
<groupId>com.google.gwt</groupId>
<artifactId>gwt-user</artifactId>
<version>${gwtVersion}</version>
<scope>provided</scope>
</dependency>
<dependency>
<groupId>com.google.gwt</groupId>
<artifactId>gwt-dev</artifactId>
<version>${gwtVersion}</version>
<classifier>${platform}-libs</classifier>
<type>zip</type>
<scope>provided</scope>
</dependency>
<dependency>
<groupId>com.google.gwt</groupId>
<artifactId>gwt-dev</artifactId>
<version>${gwtVersion}</version>
<classifier>${platform}</classifier>
<scope>provided</scope>
</dependency>
You then also need to specify some properties to the dependency plugin so it knows what how and where to unpack the gwt native libs dependency (the one with the platform-libs classifier).
For example:
<plugins>
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-dependency-plugin</artifactId>
<executions>
<execution>
<id>unpack</id>
<phase>package</phase>
<goals>
<goal>unpack</goal>
</goals>
<configuration>
<artifactItems>
<artifactItem>
<groupId>com.google.gwt</groupId>
<artifactId>gwt-dev</artifactId>
<version>${gwtVersion}</version>
<classifier>${platform}-libs</classifier>
<type>zip</type>
<overWrite>false</overWrite>
<outputDirectory>${settings.localRepository}/com/google/gwt/gwt-dev/${gwtVersion}</outputDirectory>
</artifactItem>
</artifactItems>
</configuration>
</execution>
</executions>
</plugin>
</plugins>
Also, with automatic mode, you may want to configure profiles for each platform.
For example:
<!-- profiles (with activation per platform) -->
<profiles>
<profile>
<id>gwt-dev-windows</id>
<properties>
<platform>windows</platform>
</properties>
<activation>
<activeByDefault>true</activeByDefault>
<os>
<family>Windows</family>
</os>
</activation>
</profile>
<profile>
<id>gwt-dev-mac</id>
<properties>
<platform>mac</platform>
</properties>
<activation>
<activeByDefault>false</activeByDefault>
<os>
<family>mac</family>
</os>
</activation>
</profile>
<profile>
<id>gwt-dev-linux</id>
<properties>
<platform>linux</platform>
</properties>
<activation>
<activeByDefault>false</activeByDefault>
<os>
<name>Linux</name>
</os>
</activation>
</profile>
</profiles>
For a complete automatic mode POM example see the examples page (menu at left).
If you are going to setup GWT manually, you will need to first download GWT, and unpackage it (http://code.google.com/webtoolkit/download.html).
Then, you will need to tell GWT-Maven where GWT is. This can be done with the "gwtHome" configuration property to the plugin itself, or with the "google.webtoolkit.home" property.
For example when using a settings.xml machine-wide profile:
<?xml version="1.0" encoding="UTF-8"?>
<settings>
<profiles>
<profile>
<id>gwt-1.5.2-mac</id>
<properties>
<google.webtoolkit.home>/opt/gwt-mac-1.5.2</google.webtoolkit.home>
<!-- XstartOnFirstThread needed only on the mac -->
<google.webtoolkit.extrajvmargs>-Xmx512m -XstartOnFirstThread</google.webtoolkit.extrajvmargs>
</properties>
</profile>
</profiles>
<activeProfiles>
<activeProfile>gwt-1.5.2-mac</activeProfile>
</activeProfiles>
</settings>
For manual mode you also need the GWT dependencies defined (these are still required because plugins and goals other than GWT-Maven need them, like the standard compiler).
Note that with manual mode even though the dependencies are still needed, the difference is that the source of the dependencies can be a locally installed GWT location - and there is no separate step to unpack the native libraries (they are already in google.webtoolkit.home).
For example:
<dependency>
<groupId>com.google.gwt</groupId>
<artifactId>gwt-servlet</artifactId>
<version>${gwtVersion}</version>
<scope>runtime</scope>
</dependency>
<dependency>
<groupId>com.google.gwt</groupId>
<artifactId>gwt-user</artifactId>
<version>${gwtVersion}</version>
<scope>system</scope>
<systemPath>/opt/gwt-mac-1.5.2/gwt-user.jar</systemPath>
</dependency>
<dependency>
<groupId>com.google.gwt</groupId>
<artifactId>gwt-dev</artifactId>
<version>${gwtVersion}</version>
<classifier>${platform}</classifier>
<scope>system</scope>
<systemPath>/opt/gwt-mac-1.5.2/gwt-dev-mac.jar</systemPath>
</dependency>
For a complete manual mode POM example see the examples page (menu at left).