第二十四章. Groovy 插件

要使用 Groovy 的插件，请在构建脚本中包含以下内容：
To use the Groovy plugin, include in your build script:

apply plugin: 'groovy'

Groovy 的插件向项目中添加了以下任务。
The Groovy plugin adds the following tasks to the project.

Groovy 的插件向 Java 插件所加入的任务添加了以下依赖。
The Groovy plugin adds the following dependencies to tasks added by the Java plugin.

图 24.1. Groovy 插件——任务 - Figure 24.1. Groovy plugin - tasks

Groovy 插件会假定项目的布局如表 24.3，“Groovy 插件——项目布局”所示。所有的 Groovy 源码目录都可以包含 Groovy 和 Java 代码。 Java 源码目录可能只包含 Java 源代码。 ^[11]这些目录都不需要一定存在或者包含有内容。Groovy 插件只会进行编译，而不管它发现什么。
The Groovy plugin assumes the project layout shown in Table 24.3, “Groovy plugin - project layout”. All the Groovy source directories can contain Groovy and Java code. The Java source directories may only contain Java source code. ^[11] None of these directories need to exist or have anything in them; the Groovy plugin will simply compile whatever it finds.

sourceSets {
    main {
        groovy {
            srcDirs = ['src/groovy']
        }
    }

    test {
        groovy {
            srcDirs = ['test/groovy']
        }
    }
}

由于 Gradle 的构建语言基于 Groovy，并且部分的 Gradle 使用 Groovy 实现，所以 Gradle 已经附带了一个 Groovy 库（自 Gradle 1.6 起所带的 Groovy 库的版本是 1.8.6）。不过，Groovy 项目需要显式地声明一个 Groovy 依赖。这个依赖将被用于编译和运行时类路径。它也将分别用于获取 Groovy 编译器和 Groovydoc 工具。
Because Gradle's build language is based on Groovy, and parts of Gradle are implemented in Groovy, Gradle already ships with a Groovy library (1.8.6 as of Gradle 1.6). Nevertheless, Groovy projects need to explicitly declare a Groovy dependency. This dependency will then be used on compile and runtime class paths. It will also be used to get hold of the Groovy compiler and Groovydoc tool, respectively.

如果 Groovy 用于生产代码，应该将 Groovy 依赖添加到 compile 配置中：
If Groovy is used for production code, the Groovy dependency should be added to the compile configuration:

repositories {
    mavenCentral()
}

dependencies {
    compile 'org.codehaus.groovy:groovy-all:2.3.3'
}

如果 Groovy 仅用于测试代码，应该将 Groovy 的依赖添加到 testCompile 配置中：
If Groovy is only used for test code, the Groovy dependency should be added to the testCompile configuration:

dependencies {
    testCompile "org.codehaus.groovy:groovy:2.3.3"
}

如果要使用 Gradle 附带的 Groovy 库，请声明一个 localGroovy() 依赖。请注意，不同的 Gradle 版本所附带的 Groovy 版本不同；因此，声明一个固定的 Groovy 依赖要比使用 localGroovy() 更安全一些。
To use the Groovy library that ships with Gradle, declare a localGroovy() dependency. Note that different Gradle versions ship with different Groovy versions; as such, using localGroovy() is less safe then declaring a regular Groovy dependency.

dependencies {
    compile localGroovy()
}

Groovy 库不一定得从远程仓库中获取，它也可能获取自检入代码控制的本地 lib 目录：
The Groovy library doesn't necessarily have to come from a remote repository. It could also come from a local lib directory, perhaps checked in to source control:

repositories {
    flatDir { dirs 'lib' }
}

dependencies {
    compile module('org.codehaus.groovy:groovy:1.6.0') {
        dependency('asm:asm-all:2.2.3')
        dependency('antlr:antlr:2.7.7')
        dependency('commons-cli:commons-cli:1.2')
        module('org.apache.ant:ant:1.9.3') {
            dependencies('org.apache.ant:ant-junit:1.9.3@jar', 'org.apache.ant:ant-launcher:1.9.3')
        }
    }
}

GroovyCompile 和 GroovyDoc 任务以两种方式使用Groovy：在它们的 classpath 以及它们的 groovyClasspath 上。前者用于查找源代码引用的类，并且通常包含 Groovy 库以及其他库。后者用于分别加载和执行 Groovy 编译器和 Groovydoc 工具，并且应该只包含 Groovy库及其依赖。
GroovyCompile and Groovydoc tasks consume Groovy in two ways: on their classpath, and on their groovyClasspath. The former is used to locate classes referenced by the source code, and will typically contain the Groovy library along with other libraries. The latter is used to load and execute the Groovy compiler and Groovydoc tool, respectively, and should only contain the Groovy library and its dependencies.

除非显式地配置了一个任务的 groovyClasspath，否则 Groovy（基础）插件会尝试从任务的 classpath 推断出它，以如下方式进行：
Unless a task's groovyClasspath is configured explicitly, the Groovy (base) plugin will try to infer it from the task's classpath. This is done as follows:

Groovy 插件不会向项目添加任何的约定属性。
The Groovy plugin does not add any convention properties to the project.

Groovy 插件向项目中的每个源集添加了以下，约定属性。你可以在构建脚本中把它们当成是源集对象的属性一样去使用（请参阅《第 21.3 节，“公约”）》。
The Groovy plugin adds the following convention properties to each source set in the project. You can use these properties in your build script as though they were properties of the source set object (see Section 21.3, “Conventions”).

这些属性由一个 GroovySourceSet 类的约定对象提供。
These properties are provided by a convention object of type GroovySourceSet.

Groovy 的插件还修改了一些源集的属性：
The Groovy plugin also modifies some source set properties:

Groovy 插件向项目中的每一个源集添加了一个 GroovyCompile 任务。该任务类型扩展了 JavaCompile 任务（请参阅《第 23.11 节，“CompileJava”》）。该 GroovyCompile 任务支持官方 Groovy 编译器的大多数配置选项。
The Groovy plugin adds a GroovyCompile task for each source set in the project. The task type extends the JavaCompile task (see Section 23.11, “CompileJava”). The GroovyCompile task supports most configuration options of the official Groovy compiler.