第二章-概述

Gradle的核心在于基于Groovy的丰富而可扩展的域描述语言(DSL)。 Groovy通过声明性的语言元素将基于声明的构建推向下层，你可以按你想要的方式进行组合。 这些元素同样也为支持Java, Groovy, OSGi, Web和Scala项目提供了基于约定的构建。 并且，这种声明性的语言是可以扩展的。你可以添加新的或增强现有的语言元素。 因此，它提供了简明、可维护和易理解的构建。
At the heart of Gradle lies a rich extensible Domain Specific Language (DSL) based on Groovy. Gradle pushes declarative builds to the next level by providing declarative language elements that you can assemble as you like. Those elements also provide build-by-convention support for Java, Groovy, OSGi, Web and Scala projects. Even more, this declarative language is extensible. Add your own new language elements or enhance the existing ones. Thus providing concise, maintainable and comprehensible builds.

声明性语言优点在于通用任务图，你可以将其充分利用在构建中. 它提供了最大限度的灵活性，以让Gradle适应你的特殊需求。
The declarative language lies on top of a general purpose task graph, which you can fully leverage in your builds. It provides utmost flexibility to adapt Gradle to your unique needs.

Gradle的灵活和丰富性最终能够支持在你的构建中应用通用的设计模式。 例如，它可以很容易地将你的构建拆分为多个可重用的模块，最后再进行组装，但不要强制地进行模块的拆分。 不要把原本在一起的东西强行分开（比如在你的项目结构里），从而避免让你的构建变成一场噩梦。 最后，你可以创建一个结构良好，易于维护，易于理解的构建。
The suppleness and richness of Gradle finally allows you to apply common design principles to your build. For example, it is very easy to compose your build from reusable pieces of build logic. Inline stuff where unnecessary indirections would be inappropriate. Don't be forced to tear apart what belongs together (e.g. in your project hierarchy). Thus avoiding smells like shotgun changes or divergent change that turn your build into a maintenance nightmare. At last you can create a well structured, easily maintained, comprehensible build.

Gradle允许你在构建执行的整个生命周期，对它的核心配置及执行行为进行监视并自定义。
From being a pleasure to be used embedded to its many hooks over the whole lifecycle of build execution, Gradle allows you to monitor and customize its configuration and execution behavior to its very core.

Gradle有非常良好的扩展性。 从简单的单项目构建，到庞大的多项目构建，它都能显著地提升你的效率。 这才是真正的结构化构建。通过最先进的增量构建功能，它可以解决许多大型企业所面临的性能瓶颈问题。
Gradle scales very well. It significantly increases your productivity, from simple single project builds up to huge enterprise multi-project builds. This is true for structuring the build. With the state-of-art incremental build function, this is also true for tackling the performance pain many large enterprise builds suffer from.

Gradle对多项目构建的支持非常出色。项目依赖是首先需要考虑的问题。 我们允许你在多项目构建当中对项目依赖关系进行建模，因为它们才是你真正的问题域。 Gradle遵守你的布局。
Gradle's support for multi-project build is outstanding. Project dependencies are first class citizens. We allow you to model the project relationships in a multi-project build as they really are for your problem domain. Gradle follows your layout not vice versa.

Gradle提供了局部构建的功能。 如果你在构建一个单独的子项目，Gradle也会帮你构建它所依赖的所有子项目。 你也可以选择重新构建依赖于特定子项目的子项目。 这种增量构建将使得在大型构建任务中省下大量时间。
Gradle provides partial builds. If you build a single subproject Gradle takes care of building all the subprojects that subproject depends on. You can also choose to rebuild the subprojects that depend on a particular subproject. Together with incremental builds this is a big time saver for larger builds.

不同的团队喜欢用不同的方式来管理他们的外部依赖。 从Maven和Ivy的远程仓库的传递依赖管理，到本地文件系统的jar包或目录,Gradle对所有的管理策略都提供了方便的支持。
Different teams prefer different ways to manage their external dependencies. Gradle provides convenient support for any strategy. From transitive dependency management with remote Maven and Ivy repositories to jars or dirs on the local file system.

Ant tasks是最重要的。而更有趣的是，Ant projects也是最重要的。 Gradle对任意的Ant项目提供了深度导入，并在运行时将Ant 目标(target)转换为原生的Gradle 任务(task)。 你可以从Gradle上依赖它们(Ant targets)，增强它们，甚至在你的build.xml上定义对Gradle tasks的依赖。Gradle为属性、路径等等提供了同样的整合。
Ant tasks are first class citizens. Even more interesting, Ant projects are first class citizens as well. Gradle provides a deep import for any Ant project, turning Ant targets into native Gradle tasks at runtime. You can depend on them from Gradle, you can enhance them from Gradle, you can even declare dependencies on Gradle tasks in your build.xml. The same integration is provided for properties, paths, etc ...

Gradle完全支持用于发布或检索依赖的Maven或Ivy仓库。 Gradle同样提供了一个转换器，用于将一个Maven pom.xml文件转换为一个Gradle脚本。Maven项目的运行时导入的功能将很快会有。
Gradle fully supports your existing Maven or Ivy repository infrastructure for publishing and retrieving dependencies. Gradle also provides a converter for turning a Maven pom.xml into a Gradle script. Runtime imports of Maven projects will come soon.

Gradle能适应你已有的任何结构。因此，你总可以在你构建项目的同一个分支当中开发你的Gradle构建脚本，并且它们能够并行进行。 我们通常建议编写测试，以保证生成的文件是一样的。 这种移植方式会尽可能的可靠和减少破坏性。这也是重构的最佳做法。
Gradle can adapt to any structure you have. Therefore you can always develop your Gradle build in the same branch where your production build lives and both can evolve in parallel. We usually recommend to write tests that make sure that the produced artifacts are similar. That way migration is as less disruptive and as reliable as possible. This is following the best-practices for refactoring by applying baby steps.

Gradle的构建脚本是采用Groovy写的，而不是用XML。 但与其他方法不同，它并不只是展示了由一种动态语言编写的原始脚本的强大。 那样将导致维护构建变得很困难。 Gradle的整体设计是面向被作为一门语言，而不是一个僵化的框架。 并且Groovy是我们允许你通过抽象的Gradle描述你个人的story的黏合剂。 Gradle提供了一些标准通用的story。这是我们相比其他声明性构建系统的主要特点。 我们的Groovy支持也不是简单的糖衣层，整个Gradle的API都是完全groovy化的。只有通过Groovy才能去运用它并对它提高效率。
Gradle's build scripts are written in Groovy, not XML. But unlike other approaches this is not for simply exposing the raw scripting power of a dynamic language. That would just lead to a very difficult to maintain build. The whole design of Gradle is oriented towards being used as a language, not as a rigid framework. And Groovy is our glue that allows you to tell your individual story with the abstractions Gradle (or you) provide. Gradle provides some standard stories but they are not privileged in any form. This is for us a major distinguishing features compared to other declarative build systems. Our Groovy support is also not just some simple coating sugar layer. The whole Gradle API is fully groovynized. Only by that using Groovy is the fun and productivity gain it can be.

Gradle Wrapper允许你在没有安装Gradle的机器上执行Gradle构建。 这一点是非常有用的。比如，对一些持续集成服务来说。 它对一个开源项目保持低门槛构建也是非常有用的。 Wrapper对企业来说也很有用，它使得对客户端计算机零配置。 它强制使用指定的版本，以减少兼容支持问题。
The Gradle Wrapper allows you to execute Gradle builds on machines where Gradle is not installed. This is useful for example for some continuous integration servers. It is also useful for an open source project to keep the barrier low for building it. The wrapper is also very interesting for the enterprise. It is a zero administration approach for the client machines. It also enforces the usage of a particular Gradle version thus minimizing support issues.

Gradle是一个开源项目，并遵循ASL许可。
Gradle is an open source project, and is licensed under the ASL.