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Groovy in Action, Second Edition is a thoroughly revised, comprehensive guide to Groovy programming. It introduces Java developers to the dynamic features that Groovy provides, and shows how to apply Groovy to a range of tasks including building new apps, integration with existing code, and DSL development. Covers Groovy 2.4.A clear and detailed exposition of what is groovy about Groovy. I'm glad to have it on my bookshelf.
About the Technology
In the last ten years, Groovy has become an integral part of a Java developer's toolbox. Its comfortable, common-sense design, seamless integration with Java, and rich ecosystem that includes the Grails web framework, the Gradle build system, and Spock testing platform have created a large Groovy communityAbout the book
Groovy in Action, Second Edition is the undisputed definitive reference on the Groovy language. Written by core members of the Groovy language team, this book presents Groovy like no other can-from the inside out. With relevant examples, careful explanations of Groovy's key concepts and features, and insightful coverage of how to use Groovy in-production tasks, including building new applications, integration with existing code, and DSL development, this is the only book you'll need. Updated for Groovy 2.4.
Table of Contents takes you straight to the bookdetailed table of contents
foreword to the first edition
preface
acknowledgments
about this book
about the authors
Part 1 The Groovy language
1. Your way to Groovy
1.1. The Groovy story
1.1.1. What is Groovy?
1.1.2. Playing nicely with Java: seamless integration
1.1.3. Power in your code: a feature-rich language
1.1.4. Community driven but corporate backed
1.2. What Groovy can do for you
1.2.1. Groovy for the busy Java professional
1.2.2. Groovy for the polyglot programmer
1.2.3. Groovy for pragmatic programmers, extremos, and agilists
1.3. Running Groovy
1.3.1. Using groovysh for a welcome message
1.3.2. Using groovyConsole
1.3.3. Using the groovy command
1.4. Compiling and running Groovy
1.4.1. Compiling Groovy with groovyc
1.4.2. Running a compiled Groovy script with Java
1.5. Groovy IDE and editor support
1.5.1. IntelliJ IDEA plug-in
1.5.2. NetBeans IDE plug-in
1.5.3. Eclipse plug-in
1.5.4. Groovy support in other editors
1.6. Summary
2. Overture: Groovy basics
2.1. General code appearance
2.1.1. Commenting Groovy code
2.1.2. Comparing Groovy and Java syntax
2.1.3. Beauty through brevity
2.2. Probing the language with assertions
2.3. Groovy at a glance
2.3.1. Declaring classes
2.3.2. Using scripts
2.3.3. GroovyBeans
2.3.4. Annotations
2.3.5. Using grapes
2.3.6. Handling text
2.3.7. Numbers are objects
2.3.8. Using lists, maps, and ranges
2.3.9. Code as objects: closures
2.3.10. Groovy control structures
2.4. Groovy’s place in the Java environment
2.4.1. My class is your class
2.4.2. GDK: the Groovy library
2.4.3. Groovy compiler lifecycle
2.5. Summary
3. Simple Groovy datatypes
3.1. Objects, objects everywhere
3.1.1. Java’s type system: primitives and references
3.1.2. Groovy’s answer: everything’s an object
3.1.3. Interoperating with Java: automatic boxing and unboxing
3.1.4. No intermediate unboxing
3.2. The concept of optional typing
3.2.1. Assigning types
3.2.2. Dynamic Groovy is type safe
3.2.3. Let the casting work for you
3.2.4. The case for optional typing
3.3. Overriding operators
3.3.1. Overview of overridable operators
3.3.2. Overridden operators in action
3.3.3. Making coercion work for you
3.4. Working with strings
3.4.1. Varieties of string literals
3.4.2. Working with GStrings
3.4.3. From Java to Groovy
3.5. Working with regular expressions
3.5.1. Specifying patterns in string literals
3.5.2. Applying patterns
3.5.3. Patterns in action
3.5.4. Patterns and performance
3.5.5. Patterns for classification
3.6. Working with numbers
3.6.1. Coercion with numeric operators
3.6.2. GDK methods for numbers
3.7. Summary
4. Collective Groovy datatypes
4.1. Working with ranges
4.1.1. Specifying ranges
4.1.2. Ranges are objects
4.1.3. Ranges in action
4.2. Working with lists
4.2.1. Specifying lists
4.2.2. Using list operators
4.2.3. Using list methods
4.2.4. Lists in action
4.3. Working with maps
4.3.1. Specifying maps
4.3.2. Using map operators
4.3.3. Maps in action
4.4. Notes on Groovy collections
4.4.1. Understanding concurrent modification
4.4.2. Distinguishing between copy and modify semantics
4.5. Summary
5. Working with closures
5.1. A gentle introduction to closures
5.2. The case for closures
5.2.1. Using iterators
5.2.2. Handling resources with a protocol
5.3. Declaring closures
5.3.1. Simple declaration
5.3.2. Using assignments for declaration
5.3.3. Referring to methods as closures
5.3.4. Comparing the available options
5.4. Using closures
5.4.1. Calling a closure
5.4.2. More closure capabilities
5.5. Understanding closure scope
5.5.1. Simple variable scope
5.5.2. Inspecting closure scope
5.5.3. Scoping at work: the classic accumulator test
5.6. Returning from closures
5.7. Support for design patterns
5.7.1. Relationship to the Visitor pattern
5.7.2. Relationship to the Builder pattern
5.7.3. Relationship to other patterns
5.8. Summary
6. Groovy control structures
6.1. Groovy truth
6.1.1. Evaluating Boolean tests
6.1.2. Assignments within Boolean tests
6.2. Conditional execution structures
6.2.1. The humble if statement
6.2.2. The conditional ?: operator and Elvis
6.2.3. The switch statement and the in operator
6.2.4. Sanity checking with assertions
6.3. Looping
6.3.1. Looping with while
6.3.2. Looping with for
6.4. Exiting blocks and methods
6.4.1. Normal termination: return/break/continue
6.4.2. Exceptions: throw/try-catch-finally
6.5. Summary
7. Object orientation, Groovy style
7.1. Defining classes and scripts
7.1.1. Defining fields and local variables
7.1.2. Methods and parameters
7.1.3. Safe dereferencing with the ?. operator
7.1.4. Constructors
7.2. Organizing classes and scripts
7.2.1. File to class relationship
7.2.2. Organizing classes in packages
7.2.3. Further classpath considerations
7.3. Advanced object-oriented features
7.3.1. Using inheritance
7.3.2. Using interfaces
7.3.3. Multimethods
7.3.4. Using traits
7.4. Working with GroovyBeans
7.4.1. Declaring beans
7.4.2. Working with beans
7.4.3. Using bean methods for any object
7.4.4. Fields, accessors, maps, and Expando
7.5. Using advanced syntax features
7.5.1. Querying objects with GPaths
7.5.2. Injecting the spread operator
7.5.3. Concise syntax with command chains
7.6. Summary
8. Dynamic programming with Groovy
8.1. What is dynamic programming?
8.2. Meta Object Protocol
8.3. Customizing the MOP with hook methods
8.3.1. Customizing methodMissing
8.3.2. Customizing propertyMissing
8.3.3. Using closures for dynamic hooks
8.3.4. Customizing GroovyObject methods
8.4. Modifying behavior through the metaclass
8.4.1. MetaClass knows it all
8.4.2. How to find the metaclass and invoke methods
8.4.3. Setting other metaclasses
8.4.4. Expanding the metaclass
8.4.5. Temporary MOP modifications using category classes
8.4.6. Writing extension modules
8.4.7. Using the @Category annotation
8.4.8. Merging classes with Mixins
8.5. Real-world dynamic programming in action
8.5.1. Calculating with metrics
8.5.2. Replacing constructors with factory methods
8.5.3. Fooling IDEs for fun and profit
8.5.4. Undoing metaclass modifications
8.5.5. The Intercept/Cache/Invoke pattern
8.6. Summary
9. Compile-time metaprogramming and AST transformations
9.1. A brief history
9.1.1. Generating bytecode, not source code
9.1.2. Putting the power of code generation in the hands of developers
9.2. Making Groovy cleaner and leaner
9.2.1. Code-generation transformations
9.2.2. Class design and design pattern annotations
9.2.3. Logging improvements
9.2.4. Declarative concurrency
9.2.5. Easier cloning and externalizing
9.2.6. Scripting support
9.2.7. More transformations
9.3. Exploring AST
9.3.1. Tools of the trade
9.3.2. Other tools
9.4. AST by example: creating ASTs
9.4.1. Creating by hand
9.4.2. AstBuilder.buildFromSpec
9.4.3. AstBuilder.buildFromString
9.4.4. AstBuilder.buildFromCode
9.5. AST by example: local transformations
9.6. AST by example: global transformations
9.7. Testing AST transformations
9.8. Limitations
9.8.1. It’s early binding
9.8.2. It’s fragile
9.8.3. It adds complexity
9.8.4. Its syntax is fixed
9.8.5. It’s not typed
9.8.6. It’s unhygienic
9.9. Next steps
9.10. Summary
10. Groovy as a static language
10.1. Motivation for optional static typing
10.1.1. The role of types in Groovy
10.1.2. Type checking a dynamic language?
10.2. Using @TypeChecked
10.2.1. Finding typos
10.2.2. Resolving method calls
10.2.3. Checking assignments
10.2.4. Type inference
10.2.5. Type-checked Grooviness
10.2.6. Type checking closures
10.2.7. Revisiting dynamic features in light of type checking
10.2.8. Mixing type-checked code with dynamic code
10.3. Flow typing
10.3.1. Least upper bound
10.3.2. Smart instanceof inference
10.3.3. Closure-shared variables
10.4. Static compilation
10.4.1. @CompileStatic
10.4.2. Method dispatch
10.5. Static type checking extensions
10.5.1. @DelegatesTo revisited
10.5.2. Type checking extension scripts
10.5.3. Limits
10.6. Summary
Part 2 Around the Groovy library
11. Working with builders
11.1. Learning by example: Using a builder
11.2. Building object trees with NodeBuilder
11.2.1. NodeBuilder in action: a closer look at builder code
11.2.2. Understanding the builder concept
11.2.3. Smart building with logic
11.3. Working with MarkupBuilder
11.3.1. Building XML
11.3.2. Building HTML
11.4. Working with StreamingMarkupBuilder
11.5. Task automation with AntBuilder
11.5.1. From Ant scripts to Groovy scripts
11.5.2. How AntBuilder works
11.5.3. Smart automation scripts with logic
11.6. Easy GUIs with SwingBuilder
11.6.1. Reading a password with SwingBuilder
11.6.2. Creating Swing widgets
11.6.3. Arranging your widgets
11.6.4. Referring to widgets
11.6.5. Using Swing actions
11.6.6. Using models
11.6.7. Binding made easy
11.6.8. Putting it all together
11.7. Modern UIs with GroovyFX SceneGraphBuilder
11.7.1. Application design with FXML
11.7.2. Properties and binding
11.7.3. Groovy desktop applications
11.8. Creating your own builder
11.8.1. Subclassing BuilderSupport
11.8.2. Subclassing FactoryBuilderSupport
11.8.3. Rolling your own
11.9. Summary
12. Working with the GDK
12.1. Working with objects
12.1.1. Interactive objects
12.1.2. Convenient Object methods
12.1.3. Iterative Object methods
12.2. Working with files and I/O
12.2.1. Traversing the filesystem
12.2.2. Reading from input sources
12.2.3. Writing to output destinations
12.2.4. Filters and conversions
12.2.5. Streaming serialized objects
12.2.6. temporary data and file copying
12.3. Working with threads and processes
12.3.1. Groovy multithreading
12.3.2. Integrating external processes
12.4. Working with templates
12.4.1. Understanding the template format
12.4.2. Templates in action
12.4.3. Advanced template issues
12.5. Working with Groovlets
12.5.1. Starting with "Hello world"
12.5.2. Groovlet binding
12.5.3. Templating Groovlets
12.6. Summary
13. Database programming with Groovy
13.1. Groovy SQL: a better JDBC
13.1.1. Setting up for database access
13.1.2. Executing SQL
13.2. Advanced Groovy SQL
13.2.1. Performing transactional updates
13.2.2. Working with batches
13.2.3. Working with pagination
13.2.4. Fetching metadata
13.2.5. Working with named and named-ordinal parameters
13.2.6. Using stored procedures
13.3. DataSets for SQL without SQL
13.3.1. Using DataSet operations
13.3.2. DataSets on database views
13.4. Organizing database work
13.4.1. Architectural overview
13.4.2. Specifying the application behavior
13.4.3. Implementing the infrastructure
13.4.4. Using a transparent domain model
13.4.5. Implementing the application layer
13.5. Groovy and NoSQL
13.5.1. MongoDB: A document-style database
13.5.2. Neo4J: A graph database
13.6. Other approaches
13.7. Summary
14. Working with XML and JSON
14.1. Reading XML documents
14.1.1. Working with a DOM parser
14.1.2. Reading with a Groovy parser
14.1.3. Reading with a SAX parser
14.1.4. Reading with a StAX parser
14.2. Processing XML
14.2.1. In-place processing
14.2.2. Streaming processing
14.2.3. Updating XML
14.2.4. Combining with XPath
14.3. Parsing and building JSON
14.3.1. Parsing JSON
14.3.2. Building JSON
14.4. Summary
15. Interacting with Web Services
15.1. An overview of Web Services
15.2. Reading RSS and ATOM
15.3. Using a REST-based API
15.4. Using XML-RPC
15.5. Applying SOAP
15.5.1. Doing SOAP with plain Groovy
15.5.2. Simplifying SOAP access using HTTPBuilder
15.5.3. Simplifying SOAP access using groovy-wslite
15.6. Summary
16. Integrating Groovy
16.1. Prelude to integration
16.1.1. Integrating appropriately
16.1.2. Setting up dependencies
16.2. Evaluating expressions and scripts with GroovyShell
16.2.1. Starting simply
16.2.2. Passing parameters within a binding
16.2.3. Generating dynamic classes at runtime
16.2.4. Parsing scripts
16.2.5. Running scripts or classes
16.2.6. Further parameterization of GroovyShell
16.3. Using the Groovy script engine
16.3.1. Setting up the engine
16.3.2. Running scripts
16.3.3. Defining a different resource connector
16.4. Working with the GroovyClassLoader
16.4.1. Parsing and loading Groovy classes
16.4.2. The chicken and egg dependency problem
16.4.3. Providing a custom resource loader
16.4.4. Playing it safe in a secured sandbox
16.5. Spring integration
16.5.1. Wiring GroovyBeans
16.5.2. Refreshable beans
16.5.3. Inline scripts
16.6. Riding Mustang and JSR-223
16.6.1. Introducing JSR-223
16.6.2. The script engine manager and its script engines
16.6.3. Compilable and invocable script engines
16.6.4. Polyglot programming
16.7. Mastering CompilerConfiguration
16.7.1. The import customizer
16.7.2. The source-aware customizer
16.7.3. Writing your own customizer
16.7.4. The configscript compilation option
16.8. Choosing an integration mechanism
16.9. Summary
Part 3 Applied Groovy
17. Unit testing with Groovy
17.1. Getting started
17.1.1. Writing tests is easy
17.1.2. GroovyTestCase: an introduction
17.1.3. Working with GroovyTestCase
17.2. Unit testing Groovy code
17.3. Unit testing Java code
17.4. Organizing your tests
17.4.1. Test suites
17.4.2. Parameterized or data-driven testing
17.4.3. Property-based testing
17.5. Advanced testing techniques
17.5.1. Testing made groovy
17.5.2. Stubbing and mocking
17.5.3. Using GroovyLogTestCase
17.5.4. Unit testing performance
17.5.5. Code coverage with Groovy
17.6. IDE integration
17.6.1. Using GroovyTestSuite
17.6.2. Using AllTestSuite
17.7. Testing with the Spock framework
17.7.1. Testing with mocks
17.7.2. Data-driven Spock tests
17.8. Build automation
17.8.1. Build integration with Gradle
17.8.2. Build integration with Maven
17.9. Summary
18. Concurrent Groovy with GPars
18.1. Concurrency for the rest of us
18.1.1. Concurrent != parallel
18.1.2. Introducing new concepts
18.2. Concurrent collection processing
18.2.1. Transparently concurrent collections
18.2.2. Available fork/join methods
18.3. Becoming more efficient with map/filter/reduce
18.4. Dataflow for implicit task coordination
18.4.1. Testing for deadlocks
18.4.2. Dataflow on sequential datatypes
18.4.3. Final thoughts on dataflow
18.5. Actors for explicit task coordination
18.5.1. Using the strengths of Groovy
18.6. Agents for delegated task coordination
18.7. Concurrency in action
18.8. Summary
19. Domain-specific languages
19.1. Groovy’s flexible nature
19.1.1. Back to omitting parentheses
19.2. Variables, constants, and method injection
19.2.1. Injecting constants through the binding
19.2.2. Injecting methods into a script
19.2.3. Adding imports and static imports automatically
19.2.4. Injecting methods (revisited)
19.2.5. Adding closures to the binding
19.3. Adding properties to numbers
19.4. Leveraging named arguments
19.5. Command chains
19.6. Defining your own control structures
19.7. Context switching with closures
19.8. Another technique for builders
19.9. Securing your DSLs
19.9.1. Introducing SecureASTCustomizer
19.9.2. The ArithmeticShell
19.9.3. Stopping the execution of your programs
19.9.4. Preventing cheating with metaprogramming
19.10. Testing and error reporting
19.11. Summary
20. The Groovy ecosystem
20.1. Groovy Grapes for self-contained scripts
20.2. Scriptom for Windows automation
20.3. GroovyServ for quick startup
20.4. Gradle for project automation
20.5. CodeNarc for static code analysis
20.6. GContracts for improved design
20.7. Grails for web development
20.8. Griffon for desktop applications
20.9. Gaelyk for Groovy in the cloud
20.10. Summary
Appendix A: Installation and documentation
A.1. Installing Groovy
A.2. Obtaining up-to-date documentation
A.2.1. Using online resources
A.2.2. Connecting to the book’s forum
Appendix B: Groovy language information
B.1. Operator precedence
B.2. Keyword list
B.3. Modules
Appendix C: GDK API quick reference
C.1. Array of primitives
C.2. The groovy.lang package
C.3. The groovy.sql package
C.4. The java.awt package
C.5. The java.io package
C.6. The java.lang package
C.7. The java.math package
C.8. The java.net package
C.9. The java.nio.file package
C.10. The java.sql package
C.11. The java.util package
C.12. The java.util.concurrent package
C.13. The java.util.regex package
C.14. The javax.swing package
C.15. The javax.swing.table package
C.16. The javax.swing.tree package
C.17. The org.w3c.dom package
Appendix D: Cheat sheets
D.1. GStrings
D.2. Lists
D.3. Closures
D.4. Regular expressions
D.5. XML GPath notation
Appendix E: Annotation parameters
Appendix F: Compiler phases
Appendix G: AST visitors
G.1. Walking and reading a tree
G.1.1. Wiring in a Visitor
Appendix H: Type checking extensions
H.1. Type checking extension API
H.1.1. The GroovyTypeCheckingExtensionSupport class
H.1.2. Virtual methods
H.1.3. Type-checking extension scope
H.2. Type checking events
H.2.1. setup
H.2.2. finish
H.2.3. unresolvedVariable
H.2.4. unresolvedProperty
H.2.5. unresolvedAttribute
H.2.6. beforeMethodCall
H.2.7. afterMethodCall
H.2.8. onMethodSelection
H.2.9. methodNotFound
H.2.10. beforeVisitMethod
H.2.11. afterVisitMethod
H.2.12. beforeVisitClass
H.2.13. afterVisitClass
H.2.14. incompatibleAssignment
H.2.15. ambiguousMethods
H.2.16. incompatibleReturnType
H.3. Extensions aren’t AST transformations
Appendix I: Android support
index
What's inside
- Comprehensive coverage of Groovy 2.4 including language features, libraries, and AST transformations
- Dynamic, static, and extensible typing
- Concurrency: actors, data parallelism, and dataflow
- Applying Groovy: Java integration, XML, SQL, testing, and domain-specific language support
- Hundreds of reusable examples
