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https://github.com/groovy/groovy-coreCore components of the Groovy language, including CLI tools for script execution (groovy), compilation (groovyc), interactive shells (groovysh, groovyConsole), and documentation generation (groovydoc). It includes Grape for dependency management via Apache Ivy, the java2groovy conversion tool, and bootstrap scripts (startGroovy) for JVM environment initialization on UN*X and Windows.
The MarkupTemplateEngine is a template engine designed primarily for generating XML-like markup (XML, XHTML, HTML5, etc.), though it can be used for any text-based content. Unlike traditional engines, it uses a Groovy DSL based on builder syntax.
Key features include:
Groovy is an agile and dynamic language designed for the Java Virtual Machine (JVM). It is designed to be used by Java developers with a minimal learning curve while providing several advanced capabilities:
SwingBuilder class provides a declarative and concise way to build Java Swing GUIs using Groovy's builder idiom. Instead of manually instantiating components, calling setters, and attaching children to parents, you define the component hierarchy in a nested, readable structure. This approach leverages Groovy features like closures and implicit constructor calling to make UI code more maintainable and intuitive.Groovy is supported by various IDEs and text editors with varying levels of functionality. Full support (Syntax highlighting, Code completion, and Refactoring) is typically found in dedicated Groovy-focused tools, while general-purpose editors often only provide syntax highlighting.
StaxBuilder is a Groovy builder designed to work with Streaming API for XML (StAX) processors. It allows you to generate XML documents using a Groovy DSL that interacts with the underlying StAX implementation. You can use it with the standard Java StAX implementation or with external libraries like Jettison.Groovy supports traditional design patterns from Java, but also provides language-level features that either replace certain patterns or allow them to be implemented more concisely.
Patterns in Groovy fall into three categories:
Groovy provides the AntBuilder class to script Apache Ant tasks using Groovy's builder notation. This allows you to replace XML-based Ant build.xml files with cleaner, more concise Groovy code while still utilizing the full power of Ant tasks. You can use programming constructs like variables, loops, and logical branching directly within your Ant scripts.
To use custom Ant tasks, ensure the relevant Ant JAR files are included in your classpath. AntBuilder is also available within Gradle scripts.
Groovysh is a command-line application for evaluating Groovy expressions, defining classes, and running experiments. It features rich cross-platform editing (via JLine2), ANSI colors, a command system with aliases, and user profile support.
To start the shell, run the groovysh executable. You can evaluate expressions immediately upon startup using the -e or --evaluate flag.
null. Instead of using an actual null reference—which causes NullPointerException when attempting to access fields or methods—you use a specific object that implements the required interface but performs no action (semantically equivalent to 'doing nothing'). This allows you to safely invoke methods and access fields on the placeholder without explicit null checks.MBeanServer.Joint compilation allows the Groovy compiler to parse Groovy source files, create stubs for them, and then invoke the Java compiler to compile those stubs alongside existing Java sources. This enables seamless mixing of Java and Groovy files in the same project.
Warning: If you do not enable joint compilation and attempt to compile Java source files with groovyc, the Java files will be treated as Groovy sources. While often compatible, the semantics may differ from standard Java compilation.
The Bouncer Pattern describes a method whose sole purpose is to either throw an exception (when specific conditions are met) or do nothing. These methods are primarily used to defensively guard the pre-conditions of other methods, ensuring that input arguments are valid before proceeding with logic.
In Groovy, while you can implement explicit utility methods for this purpose, the idiomatic approach is to use the assert keyword directly within your methods to perform these checks.