Groovy Programming Training Course

Introduction to Groovy

• Overview of Apache Groovy
• Historical context and evolution of the language
• The relationship between Groovy and the Java Virtual Machine
• Groovy as both a scripting and general-purpose programming language
• Common scenarios for using Groovy
• Integrating Groovy within Java-based projects
• Benefits of using Groovy in conjunction with Java
• Presentation of the sample application

Overview of Groovy Features

• Dynamic typing and the option for static typing
• Groovy's scripting capabilities
• Concise syntax and language-specific enhancements
• Closures and principles of functional programming
• Groovy collections and extended APIs
• Operator overloading techniques
• String interpolation features
• Safe navigation and the Elvis operator
• Development of Domain-Specific Languages
• Meta-programming capabilities
• Introduction to the Groovy Development Kit (GDK)

Setting up the Development Environment

• Installation and configuration of Groovy
• Utilizing Groovy distributions
• Executing Groovy from the command line
• Running Groovy scripts
• Setting up an Integrated Development Environment (IDE)
• Initializing a new Groovy project
• Managing project dependencies
• Integrating Groovy with existing Java projects
• Configuring the development environment for containerized applications

Writing Your First Groovy Application

• Creating a basic 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 simple 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 complex expressions
• Groovy-specific operators and shortcuts
• Null value handling
• Safe navigation operators
• The Elvis operator
• Multiple assignment techniques

Using Groovy's Data Types and Collections

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

Using Groovy Closures

• Conceptual understanding of closures
• Closure syntax and structure
• Defining closure parameters
• Implicit closure parameters
• Invoking closures
• Storing closures in variables
• Passing closures as method arguments
• Returning closures from methods
• Using closures with collections
• Applying closures for filtering and data transformation
• Scope management and variable capture
• Leveraging closures for functional programming
• Practical patterns for using closures

Controlling Program Flow with Groovy Control Structures

• Conditional logic statements
• if and else constructs
• Nested conditional logic
• switch statements
• Loops and iteration mechanisms
• for, while, and do-while loops
• Utilizing ranges in loop iterations
• Using closures for iteration
• break and continue statements
• Exception handling strategies
• try, catch, and finally blocks
• Raising custom exceptions
• Groovy-specific control-flow features

Implementing Object Oriented Programming (OOP) in Your Application

• Defining classes in Groovy
• Properties and fields
• Constructors
• Methods
• Encapsulation principles
• Inheritance mechanisms
• Interfaces
• Abstract classes
• Polymorphism
• Method overriding
• Method overloading
• Groovy getters and setters
• Traits
• 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 class extensions
• The MetaClass mechanism
• Dynamically adding methods
• Intercepting method calls
• Compile-time transformations
• Common Abstract Syntax Tree (AST) transformations
• Responsible use of meta-programming
• Practical examples of meta-programming

Working with Builders

• Introduction to the builder design pattern
• Purpose and utility of Groovy builders
• Constructing hierarchical structures
• XML builders
• JSON builders
• Generating HTML and markup
• Configuring builder output
• Integrating closures with builders
• Creating custom builders
• Applying builders in Domain-Specific Language development

Accessing a Database with Groovy

• Concepts of database connectivity
• Connecting Groovy applications to database systems
• JDBC and Groovy database APIs
• Configuring database connection parameters
• Executing SQL queries
• Processing query results
• Inserting, updating, and deleting records
• Using parameterized queries
• Managing transactions
• Handling database exceptions
• Working with the Groovy SQL library
• Implementing database features in the sample application

Calling Java from Groovy

• Interoperability between Groovy and Java
• Utilizing Java classes within Groovy
• Invoking Java methods
• Working with Java libraries
• Interacting with Java collections
• Handling exceptions thrown by Java code
• 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 relevant to Groovy applications
• Sending HTTP requests
• Handling GET, POST, PUT, and DELETE operations
• Working with request parameters and headers
• Processing JSON responses
• Constructing JSON request bodies
• Implementing authentication mechanisms
• Managing HTTP error responses
• Consuming external REST services
• Integrating REST functionality into the sample application

Working with the GDK

• Introduction to the Groovy Development Kit
• Enhanced Java APIs
• Advanced string handling
• Enhanced collection capabilities
• File and directory operations
• Reading from and writing to files
• Working with streams
• Processing XML data
• Processing JSON data
• Handling dates and times
• Utility methods and convenience APIs
• Selecting appropriate GDK functionalities

Unit Testing a Groovy Application

• Introduction to testing Groovy applications
• Test-driven development (TDD) concepts
• Writing unit tests
• Using popular testing frameworks
• Structuring test classes
• Writing assertions
• Testing classes and methods
• Testing closures
• Testing exception handling
• Mocking external dependencies
• Data-driven testing techniques
• Testing database-related functionality
• Testing REST integrations
• Running tests and analyzing results

Troubleshooting

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

Summary and Conclusion

• Review of core Groovy language fundamentals
• Recap of syntax, data types, and collections
• Recap of closures and functional programming concepts
• Recap of object-oriented programming principles
• Recap of meta-programming and builder patterns
• Recap of database and REST integration strategies
• Recap of Groovy and Java interoperability
• Recap of GDK capabilities
• Review of testing best practices
• Best practices for developing production-ready Groovy applications
• Final hands-on exercise
• Q&A session and discussion