Groovy Programming Training Course

Introduction to Groovy

• Overview of Apache Groovy
• Historical context and evolution of Groovy
• The relationship between Groovy and the Java Virtual Machine
• Groovy as both a scripting and programming language
• Typical use cases for Groovy
• Application of Groovy in Java-based projects
• Benefits of integrating Groovy with Java
• Introduction to the sample application

Key Features of Groovy

• Dynamic typing and optional static typing
• Scripting capabilities in Groovy
• Concise syntax and language enhancements
• Closures and functional programming concepts
• Groovy collections and enhanced APIs
• Operator overloading
• String interpolation
• Safe navigation and Elvis operators
• Development of Domain-Specific Languages
• Meta-programming capabilities
• The Groovy Development Kit (GDK)

Development Environment Setup

• Installation and configuration of Groovy
• Utilizing different Groovy distributions
• Executing Groovy commands via the command line
• Running Groovy scripts
• Setting up an IDE
• Creating a new Groovy project
• Dependency management
• Integrating Groovy into Java projects
• Configuring the environment for containerized development

Writing Your First Groovy Application

• Creating a basic Groovy script
• Understanding the structure of Groovy scripts
• Executing Groovy applications
• Utilizing the println statement
• Working with variables
• Defining methods
• Adding comments and documentation
• Constructing a simple sample application
• Compiling Groovy code

Groovy Syntax Fundamentals

• Groovy statements and expressions
• Semicolons and optional syntax elements
• Variables and constants
• Dynamic versus explicit typing
• String literals and interpolation
• Single-line and multi-line strings
• Operators and expressions
• Groovy-specific operators and shortcuts
• Null handling strategies
• Safe navigation
• The Elvis operator
• Multiple assignment

Data Types and Collections in Groovy

• Primitive and object types
• Numbers and numeric operations
• Strings and characters
• Booleans
• Date and time values
• Lists
• Maps
• Sets
• Ranges
• Iterating through collections
• Collection transformations
• Filtering and searching collections
• Sorting and grouping data
• Groovy collection methods

Using Groovy Closures

• Understanding the concept of closures
• Closure syntax
• Closure parameters
• Implicit closure parameters
• Invoking closures
• Closures as variables
• Passing closures to methods
• Returning closures from methods
• Closures in relation to collections
• Utilizing closures for filtering and transformation
• Scope and variable capture
• Closures for functional programming
• Practical closure patterns

Control Flow Structures in Groovy

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

Object-Oriented Programming (OOP) in Groovy

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

Runtime and Compile-Time Meta-Programming

• Introduction to Groovy meta-programming
• Dynamic method invocation
• Expando objects
• Manipulating methods and properties at runtime
• Categories and extensions
• 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
• Groovy builders and their purpose
• 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

Database Access with Groovy

• Database connectivity concepts
• 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

Interoperability: Calling Java from Groovy

• Groovy and Java interoperability
• Using Java classes in Groovy
• Calling Java methods
• Working with Java libraries
• Using Java collections
• Handling Java exceptions
• Comparison of Groovy and Java syntax
• Calling Groovy code from Java
• Mixing Groovy and Java source files
• Integrating Groovy into existing Java applications
• Interoperability best practices

REST Service Integration

• 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
• String manipulation
• 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 Groovy Applications

• 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