Groovy Programming Training Course

Introduction to Groovy

• Familiarization with Apache Groovy
• The background and progression of Groovy
• The relationship between Groovy and the Java Virtual Machine
• Groovy as both a scripting and programming tool
• Typical scenarios for using Groovy
• Integrating Groovy into Java-centric projects
• Benefits of pairing Groovy with Java
• Introduction to the sample project

Overview of Groovy Features

• Dynamic typing and optional static typing mechanisms
• Capabilities for scripting in Groovy
• Concise syntax and language improvements
• Closures and functional programming paradigms
• Groovy collections and enhanced APIs
• Operator overloading techniques
• String interpolation methods
• Safe navigation and the Elvis operator
• Developing Domain-Specific Languages
• Meta-programming capabilities
• The Groovy Development Kit (GDK)

Setting up the Development Environment

• Installation and configuration of Groovy
• Working with various Groovy distributions
• Utilizing Groovy via the command line
• Execution of Groovy scripts
• Configuring an Integrated Development Environment (IDE)
• Initializing a Groovy project
• Managing project dependencies
• Integrating Groovy within Java projects
• Setting up the development environment for containerized solutions

Writing Your First Groovy Application

• Creating a fundamental Groovy script
• Understanding the structure of Groovy scripts
• Executing Groovy applications
• Utilizing the println statement
• Managing variables
• Defining methods
• Incorporating comments and documentation
• Developing a basic sample application
• Compiling Groovy code

Getting Familiar with Groovy's Syntax

• Groovy statements and expressions
• Semicolons and optional syntactic elements
• Variables and constants
• Dynamic versus explicit typing
• String literals and interpolation
• Single-line and multiline string handling
• Operators and expressions
• Groovy-specific operators and shortcuts
• Null handling strategies
• Safe navigation practices
• Use of the Elvis operator
• Multiple assignment techniques

Using Groovy's Data Types and Collections

• Primitive and object types
• Numbers and numeric operations
• Strings and character handling
• Boolean logic
• Date and time-related values
• Lists
• Maps
• Sets
• Ranges
• Iterating through collections
• Transforming collections
• Filtering and searching within collections
• Sorting and grouping data
• Groovy-specific collection methods

Using Groovy Closures

• Concepts behind closures
• Closure syntax structure
• Defining closure parameters
• Implicit closure parameters
• Invoking closures
• Closures as variables
• Passing closures as method arguments
• Returning closures from methods
• Interactions between closures and collections
• Using closures for filtering and transformation
• Scope and variable capture
• Closures in functional programming
• Common closure patterns

Controlling Program Flow with Groovy Control Structures

• Conditional statements
• if and else constructs
• Nested conditions
• switch statements
• Loops and iteration logic
• for, while, and do-while loops
• Using ranges within loops
• Employing closures for iteration
• break and continue statements
• Exception handling
• try, catch, and finally blocks
• Raising custom exceptions
• Groovy-specific control-flow features

Implementing Object Oriented Programming (OOP) in Your Application

• Defining Groovy classes
• Properties and fields
• Constructors
• Methods
• Encapsulation
• Inheritance
• Interfaces
• Abstract classes
• Polymorphism
• Method overriding
• Method overloading
• Groovy getters and setters
• Traits
• Enumerations (Enums)
• Building domain models for the sample application

Runtime MetaProgramming and Compile Time MetaProgramming

• Introduction to Groovy meta-programming
• Dynamic method invocation
• Expando objects
• Manipulating methods and properties at runtime
• Categories and extensions
• The MetaClass
• Dynamically adding methods
• Intercepting method calls
• Compile-time transformations
• Common AST transformations
• Responsible use of meta-programming
• Practical meta-programming examples

Working with Builders

• Introduction to the builder pattern
• Purpose of Groovy builders
• Creating hierarchical structures
• XML builders
• JSON builders
• HTML and markup generation
• Configuring builder output
• Using closures with builders
• Creating custom builders
• Applying builders in Domain-Specific Languages

Accessing a Database with Groovy

• Concepts of database connectivity
• Connecting Groovy applications to databases
• JDBC and Groovy database APIs
• Configuring database connections
• Executing SQL queries
• Reading query results
• Inserting, updating, and deleting data
• Parameterized queries
• Transactions
• Handling database exceptions
• Working with Groovy SQL
• Building database functionality for the sample application

Calling Java from Groovy

• Groovy and Java interoperability
• Using Java classes from Groovy
• Calling Java methods
• Working with Java libraries
• Using Java collections
• Handling Java exceptions
• Comparing Groovy and Java syntax
• Calling Groovy code from Java
• Mixing Groovy and Java source files
• Integrating Groovy into existing Java applications
• Best practices for interoperability

Connecting to REST Services and Applications

• Introduction to REST APIs
• HTTP concepts for Groovy applications
• Sending HTTP requests
• Handling GET, POST, PUT, and DELETE operations
• Working with request parameters and headers
• Processing JSON responses
• Building JSON request bodies
• Handling authentication
• Managing HTTP errors
• Consuming external REST services
• Integrating REST functionality into the sample application

Working with the GDK

• Introduction to the Groovy Development Kit
• Enhanced Java APIs
• Working with strings
• Enhanced collections
• File and directory operations
• Reading and writing files
• Working with streams
• Processing XML
• Processing JSON
• Working with dates and times
• Utility methods and convenience APIs
• Selecting appropriate GDK functionality

Unit Testing a Groovy Application

• Introduction to testing Groovy applications
• Test-driven development concepts
• Writing unit tests
• Using testing frameworks
• Structuring test classes
• Assertions
• Testing classes and methods
• Testing closures
• Testing exceptions
• Mocking dependencies
• Data-driven testing
• Testing database-related functionality
• Testing REST integrations
• Running and analyzing test results

Troubleshooting

• Diagnosing Groovy syntax errors
• Debugging runtime errors
• Handling compilation problems
• Troubleshooting Java interoperability issues
• Debugging closures and collection operations
• Investigating database connectivity problems
• Troubleshooting REST API integrations
• Debugging meta-programming behavior
• Using logging and diagnostic tools
• Practical troubleshooting exercises

Summary and Conclusion

• Review of Groovy language fundamentals
• Review of syntax, types, and collections
• Review of closures and functional programming
• Review of object-oriented programming
• Review of meta-programming and builders
• Review of database and REST integration
• Review of Groovy and Java interoperability
• Review of GDK capabilities
• Review of testing practices
• Best practices for developing Groovy applications
• Final hands-on exercise
• Questions and discussion