
- •brief contents
- •contents
- •foreword
- •preface
- •acknowledgments
- •about this book
- •Roadmap
- •Code conventions and downloads
- •Author Online
- •About the author
- •about the cover illustration
- •1 Why add Groovy to Java?
- •1.1 Issues with Java
- •1.1.1 Is static typing a bug or a feature?
- •1.1.2 Methods must be in a class, even if you don’t need or want one
- •1.1.3 Java is overly verbose
- •1.1.4 Groovy makes testing Java much easier
- •1.1.5 Groovy tools simplify your build
- •1.2 Groovy features that help Java
- •1.3 Java use cases and how Groovy helps
- •1.3.1 Spring framework support for Groovy
- •1.3.2 Simplified database access
- •1.3.3 Building and accessing web services
- •1.3.4 Web application enhancements
- •1.4 Summary
- •2 Groovy by example
- •2.1 Hello, Groovy
- •2.2 Accessing Google Chart Tools
- •2.2.1 Assembling the URL with query string
- •2.2.2 Transmitting the URL
- •2.2.3 Creating a UI with SwingBuilder
- •2.3 Groovy Baseball
- •2.3.1 Database data and Plain Old Groovy Objects
- •2.3.2 Parsing XML
- •2.3.3 HTML builders and groovlets
- •2.4 Summary
- •3 Code-level integration
- •3.1 Integrating Java with other languages
- •3.2 Executing Groovy scripts from Java
- •3.2.1 Using JSR223 scripting for the Java Platform API
- •3.2.2 Working with the Groovy Eval class
- •3.2.3 Working with the GroovyShell class
- •3.2.4 Calling Groovy from Java the easy way
- •3.2.5 Calling Java from Groovy
- •3.3 Summary
- •4 Using Groovy features in Java
- •4.1 Treating POJOs like POGOs
- •4.2 Implementing operator overloading in Java
- •4.3 Making Java library classes better: the Groovy JDK
- •4.4 Cool AST transformations
- •4.4.1 Delegating to contained objects
- •4.4.2 Creating immutable objects
- •4.4.3 Creating singletons
- •4.5 Working with XML
- •4.6 Working with JSON data
- •4.7 Summary
- •5 Build processes
- •5.1 The build challenge
- •5.2 The Java approach, part 1: Ant
- •5.3 Making Ant Groovy
- •5.3.1 The <groovy> Ant task
- •5.3.2 The <groovyc> Ant task
- •5.3.3 Writing your build in Groovy with AntBuilder
- •5.3.4 Custom build scripts with Gant
- •5.3.5 Ant summary
- •5.4 The Java approach, part 2: Maven
- •5.4.2 The GMaven project
- •5.4.3 Maven summary
- •5.5 Grapes and @Grab
- •5.6 The Gradle build system
- •5.6.1 Basic Gradle builds
- •5.6.2 Interesting configurations
- •5.7 Summary
- •6 Testing Groovy and Java projects
- •6.1 Working with JUnit
- •6.1.1 A Java test for the Groovy implementation
- •6.1.2 A Groovy test for the Java implementation
- •6.1.3 A GroovyTestCase test for a Java implementation
- •6.2 Testing scripts written in Groovy
- •6.2.1 Useful subclasses of GroovyTestCase: GroovyShellTestCase
- •6.2.2 Useful subclasses of GroovyTestCase: GroovyLogTestCase
- •6.3 Testing classes in isolation
- •6.3.1 Coerced closures
- •6.3.2 The Expando class
- •6.3.3 StubFor and MockFor
- •6.4 The future of testing: Spock
- •6.4.1 The Search for Spock
- •6.4.2 Test well, and prosper
- •6.4.4 The trouble with tribbles
- •6.4.5 Other Spock capabilities
- •6.5 Summary
- •7 The Spring framework
- •7.1 A Spring application
- •7.2 Refreshable beans
- •7.3 Spring AOP with Groovy beans
- •7.4 Inline scripted beans
- •7.5 Groovy with JavaConfig
- •7.6 Building beans with the Grails BeanBuilder
- •7.7 Summary
- •8 Database access
- •8.1 The Java approach, part 1: JDBC
- •8.2 The Groovy approach, part 1: groovy.sql.Sql
- •8.3 The Java approach, part 2: Hibernate and JPA
- •8.4 The Groovy approach, part 2: Groovy and GORM
- •8.4.1 Groovy simplifications
- •8.5 Groovy and NoSQL databases
- •8.5.1 Populating Groovy vampires
- •8.5.2 Querying and mapping MongoDB data
- •8.6 Summary
- •9 RESTful web services
- •9.1 The REST architecture
- •9.3 Implementing JAX-RS with Groovy
- •9.4 RESTful Clients
- •9.5 Hypermedia
- •9.5.1 A simple example: Rotten Tomatoes
- •9.5.2 Adding transitional links
- •9.5.3 Adding structural links
- •9.5.4 Using a JsonBuilder to control the output
- •9.6 Other Groovy approaches
- •9.6.1 Groovlets
- •9.6.2 Ratpack
- •9.6.3 Grails and REST
- •9.7 Summary
- •10 Building and testing web applications
- •10.1 Groovy servlets and ServletCategory
- •10.2 Easy server-side development with groovlets
- •10.2.1 A “Hello, World!” groovlet
- •10.2.2 Implicit variables in groovlets
- •10.3.2 Integration testing with Gradle
- •10.3.3 Automating Jetty in the Gradle build
- •10.4 Grails: the Groovy “killer app”
- •10.4.1 The quest for the holy Grails
- •10.5 Summary
- •A.1 Installing a JDK
- •A.2 Installing Groovy
- •A.3 Testing your installation
- •A.4 IDE support
- •A.5 Installing other projects in the Groovy ecosystem
- •B.1 Scripts and the traditional example
- •B.2 Variables, numbers, and strings
- •B.2.1 Numbers
- •B.2.2 Strings and Groovy strings
- •B.3 Plain Old Groovy Objects
- •B.4 Collections
- •B.4.1 Ranges
- •B.4.2 Lists
- •B.4.3 Maps
- •B.5 Closures
- •B.6 Loops and conditionals
- •B.6.1 Loops
- •B.6.2 Conditionals
- •B.6.3 Elvis
- •B.6.4 Safe de-reference
- •B.7 File I/O
- •B.8.1 Parsing and slurping XML
- •B.8.2 Generating XML
- •B.8.3 Validation
- •B.9 JSON support
- •B.9.1 Slurping JSON
- •B.9.2 Building JSON
- •index
- •Symbols

14 |
CHAPTER 1 Why add Groovy to Java? |
|
|
|
dependencies { |
|
Dependencies |
|
testCompile 'junit:junit:4.10' |
||
|
in Maven form |
testCompile "org.spockframework:spock-core:0.7-groovy-2.0"
}
Now running gradle build results in a series of stages:
:compileJava
:processResources
:classes
:jar
:assemble
:compileTestJava
:processTestResources
:testClasses
:test
:check
:build
The result is a nice, hyperlinked set of documentation of all the test cases, plus a JAR file for deployment.
Of course, if there’s a plugin called java, there’s a plugin called groovy. Better yet, the Groovy plugin includes the Java plugin and, as usual, augments and improves it. If your project is similar to the ones discussed in this book, in that it combines Groovy and Java classes and uses each where most helpful, then all you need is the Groovy plugin and you’re ready to go. There are many other plugins available, including eclipse and web. I’ll talk about them in chapter 5 on build processes.
In this section I reviewed several of the features built into Java and how they can lead to code that’s more verbose and complicated than necessary. I demonstrated how Groovy can streamline implementations and even augment existing Java tools to make them easier to use and more powerful. I’ll show more details throughout the book. First I want to list some of the additional capabilities Groovy brings to Java in the next section.
1.2Groovy features that help Java
I’ve actually been discussing these all along, but let me make a few specific points here. First, the Groovy version of a Java class is almost always simpler and cleaner. Groovy is far less verbose and generally easier to read.
As true as that statement is, though, it’s a bit misleading. I’m not advocating rewriting all your Java code in Groovy. Quite the contrary; if your existing Java code works, that’s great, although you might want to consider adding test cases in Groovy if you don’t already have them. In this book, I’m more interested in helping Java than replacing it.
What does Groovy offer Java? Here’s a short list of topics that are discussed in much more detail in the rest of the book:
1Groovy adds new capabilities to existing Java classes.
Groovy includes a Groovy JDK, which documents the methods added by Groovy to the Java libraries. The various sort methods added to the Collection interface
www.it-ebooks.info