Groovy for Domain-specific Languages - Second Edition电子书

Groovy for Domain-specific Languages Second Edition

Table of Contents

Groovy for Domain-specific Languages Second Edition

Credits

About the Author

Acknowledgments

About the Reviewers

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Preface

What this book covers

What you need for this book

Who this book is for

Conventions

Reader feedback

Customer support

Downloading the example code

Errata

Piracy

Questions

1. Introduction to DSLs and Groovy

DSL – a new name for an old idea

The evolution of programming languages

General-purpose languages

Spreadsheets and 4GLs

Language-oriented programming

Who are DSLs for?

A DSL for process engineers

Stakeholder participation

DSL design and implementation

External versus internal DSLs

Operator overloading

Groovy

A natural fit with the JVM

Groovy language features

Static and optional typing

Native support for lists and maps

Closures

Groovy operator overloading

Regular expression support

Optional syntax

Groovy markup

Summary

2. Groovy Quick Start

Installing Groovy with GVM

Installing GVM

Installing GVM on Windows

How to find and install Groovy from binaries

Running Groovy

The Groovy script engine – groovy

Shebang scripts

The Groovy shell – groovysh

The Groovy console – groovyConsole

The Groovy compiler – groovyc

The Groovy IDE and editor integration

NetBeans

Eclipse

Spring STS

IntelliJ IDEA

Other IDEs and editors

Summary

3. Essential Groovy DSLs

Installing Gradle

Gradle basics

Gradle build scripts

Gradle tasks

Adding actions to tasks

Default tasks

Creating task dependencies

Built-in tasks and plugins

Plugins

The Gradle Groovy plugin

The IDEA plugin

The Eclipse plugin

Repositories

Dependencies

Spock tests

Given, when, then

Spock specification structure

Feature methods

Blocks

Fields

Fixture methods

Helper methods

Where blocks

Fixture blocks

Testing Gradle using Spock

Further reading

Summary

4. The Groovy Language

Introducing the Groovy language

The module structure

Groovy shorthand

Implicit imports

Default visibility, optional semicolon

Optional parentheses

The optional dot in method chains

Dynamic types

The optional return keyword

Properties and GroovyBeans

Assertions

Autoboxing

Strings

Regular expressions

Methods and closures

Control structures

Groovy Truth

Ternary and Elvis operators

Spaceship and Elvis operators

The switch statement

Loops

Collections

Ranges

Lists

Maps

Operators

Spread and spread-dot

Null safe dereference

Operator overloading

Summary

5. Groovy Closures

What is a closure?

Closures and collection methods

Closures as method parameters

Method parameters as DSL

Forwarding parameters

Calling closures

The implicit doCall method

Finding a named closure field

Closure parameters

Enforcing zero parameters

Parameters and the doCall method

Passing multiple parameters

Default parameter values

Implementing closures in Java

Curried parameters

Closure return values

The closure scope

The this, owner, and delegate variables

Closure composition

Closure trampoline

Closure memoization

Summary

6. Example DSL – GeeTwitter

Twitter

Working with the Twitter APIs

Using Twitter4J Java APIs

Tweeting

Direct messages

Searching

Following

Groovy improvements

A Groovier way to find friends

Groovy searching

Removing the boilerplate

Refactoring

Fleshing out GeeTwitter

Improving search

Adding a command-line interface

Adding built-in methods

Summary

7. Power Groovy DSL Features

Named parameters

Named parameters in DSLs

Command chains

Builders

The builder design pattern

Using Groovy builders

MarkupBuilder

Namespaced XML

The GroovyMarkup syntax

GroovyMarkup and HTML

Using program logic with builders

Builders for every occasion

NodeBuilder

Using GPath to navigate a node tree

SwingBuilder

Method pointers

Metaprogramming and the Groovy MOP

Reflection

Groovy reflection shortcuts

Expandos

Categories

Traits

MetaClass

Pretended methods – MetaClass.invokeMethod

Understanding this, delegate, and owner

How builders work

ExpandoMetaClasses

Replacing methods

Adding or overriding static methods

Dynamic method naming

Adding overloaded methods

Adding constructors

Summary

8. AST Transformations

What is an AST

Compiler phases

Local AST transformations

Using ASTBuilder

Build from code

Build from Spec

Traits to the rescue

Global AST transformations

A finite state machine DSL

The state machine pattern

A state machine AST transformation

Handling errors – compile errors

Building the new AST nodes

Testing the state machine DSL

Compiling and packaging an AST transformation

Summary

9. Existing Groovy DSLs

Grails object relational mapping – GORM

Grails quick start

The grails-app directory

Building a GORM model

Using domain classes

Modeling relationships

Associations

One-to-one

Constraints

One-to-many

Many-to-many

Composition

Inheritance

Mapping

Querying

Dynamic finders

GORM as a DSL

Spock as a DSL

Spock

JUnit

Summary

10. Building a Builder

The builder code structure

Closure method calls

The resolve strategy – OWNER_FIRST

Pretended methods

invokeMethod

methodMissing

The closure delegate

BuilderSupport

BuilderSupport hook methods

A database builder

FactoryBuilderSupport

Summary

11. Implementing a Rules DSL

Groovy bindings

Exploiting bindings in DSLs

Closures as built-in methods

Closures as repeatable blocks

Using a specification parameter

Closures as singleton blocks

Using binding properties to form context

Storing and communicating results

Building a rewards DSL

Designing the DSL

BroadbandPlus

Reward types

The reward DSL

Handling events – deferred execution

Convenience methods and shorthand

The offers

The RewardService class

The BroadbandPlus application classes

Testing with Spock

Summary

12. Integrating It All

Groovy as a teaching language

Hiding complexity

A game DSL for kids

A game DSL – goals

Architecture and technology choices

TicTacToe in a DSL

Implementing the AST transform

Building the game engine pattern

Testing the DSL

Class loading issues

Gradle subprojects

Debugging

The game server

Integrating with Spring Boot server

Controller annotations

JSONP

Loading the DSL

Spring Data mapping for MongoDB

The Game UI

Summary

Index