Chapter 17. The Groovy Plugin

The Groovy plugin does not add any tasks. It modifies some of the tasks of the Java Plugin.

The Groovy plugin assumes the project layout shown in Table 17.1, “Groovy plugin - project layout”. All the Groovy s ource directories can contain Groovy and Java code. The Java source directories may only contain Java source code (and can of course be empty). ^[18]

The Groovy plugin adds a dependency configuration called groovy.

Gradle is written in Groovy and allows you to write your build scripts in Groovy. But this is an internal aspect of Gradle which is strictly separated from building Groovy projects. You are free to choose the Groovy version your project should be build with. This Groovy version is not just used for compiling your code and running your tests. The groovyc compiler and the the groovydoc tool are also taken from the Groovy version you provide. As usual, with freedom comes responsibility ;). You are not just free to choose a Groovy version, you have to provide one. Gradle expects that the groovy libraries are assigned to the groovy dependency configuration. Here is an example using the public Maven repository:

repositories {
    mavenCentral()
}

dependencies {
    groovy group: 'org.codehaus.groovy', name: 'groovy-all', version: '1.6.0'
}

And here is an example using the Groovy JARs checked into the lib directory of the source tree:

repositories {
    flatDir(dirs: file('lib'))
}

dependencies {
    groovy module(':groovy-all:1.6.0') {
        dependency(':commons-cli:1.0')
        module(':ant:1.7.0') {
            dependencies(':ant-junit:1.7.0:jar', ':ant-launcher:1.7.0')
        }
    }
}

The Groovy plugin adds the convention properties shown in Table 17.2, “Groovy plugin - directory properties” and Table 17.3, “Groovy Plugin - floating directory properties”.

The GroovyCompile task has two instances, compile and compileTests. The task type extends the Compile task (see Section 16.8, “Compile”)

Have a look at GroovyCompile to learn about the details. The compile task delegates to the Ant Groovyc task to do the compile. Via the compile task you can set most of the properties of Ants Groovyc task.

In contrast to the Java plugin the fork mode is set to once by default, because of the significant startup time of Groovy. The Java plugin uses per test as fork mode (see Section 16.9, “Test”).