Book Image

Learning Java Functional Programming

By : Richard M Reese, Richard M. Reese
Book Image

Learning Java Functional Programming

By: Richard M Reese, Richard M. Reese

Overview of this book

Functional programming is an increasingly popular technology that allows you to simplify many tasks that are often cumbersome and awkward using an object-oriented approach. It is important to understand this approach and know how and when to apply it. Functional programming requires a different mindset, but once mastered it can be very rewarding. This book simplifies the learning process as a problem is described followed by its implementation using an object-oriented approach and then a solution is provided using appropriate functional programming techniques. Writing succinct and maintainable code is facilitated by many functional programming techniques including lambda expressions and streams. In this book, you will see numerous examples of how these techniques can be applied starting with an introduction to lambda expressions. Next, you will see how they can replace older approaches and be combined to achieve surprisingly elegant solutions to problems. This is followed by the investigation of related concepts such as the Optional class and monads, which offer an additional approach to handle problems. Design patterns have been instrumental in solving common problems. You will learn how these are enhanced with functional techniques. To transition from an object-oriented approach to a functional one, it is useful to have IDE support. IDE tools to refactor, debug, and test functional programs are demonstrated through the chapters. The end of the book brings together many of these functional programming techniques to create a more comprehensive application. You will find this book a very useful resource to learn and apply functional programming techniques in Java.

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Learning Java Functional Programming
Richard M Reese | Richard M. Reese
Oct, 2015 | 296 pages
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Table of Contents (16 chapters)
Learning Java Functional Programming
Learning Java Functional Programming
Credits
Credits
About the Author
About the Author
About the Reviewers
About the Reviewers
www.PacktPub.com
www.PacktPub.com
Preface
Preface
Free Chapter
1
Getting Started with Functional Programming
Getting Started with Functional Programming
Aspects of functional programming
Java 8's support for functional style programming
Summary
2
Putting the Function in Functional Programming
Putting the Function in Functional Programming
Lambda expressions usage
Functional programming concepts in Java
Lambda expressions revisited
Functional interfaces revisited
Summary
3
Function Composition and Fluent Interfaces
Function Composition and Fluent Interfaces
Introduction to function composition
Creating composite functions prior to Java 8
Creating composite functions in Java 8
Fluent interfaces
Default methods and functions
Summary
4
Streams and the Evaluation of Expressions
Streams and the Evaluation of Expressions
The Stream class and its use
Creating streams
Using the Stream class methods
Lazy and eager evaluation
Stream and concurrent processing
Summary
5
Recursion Techniques in Java 8
Recursion Techniques in Java 8
Recursive data structures
Types of recursion
Understanding recursion
Recursion implementation techniques
When to use recursion
Recursion and humor
Summary
6
Optional and Monads
Optional and Monads
Using the Optional class
Monads
Summary
7
Supporting Design Patterns Using Functional Programming
Supporting Design Patterns Using Functional Programming
Implementing the execute-around-method pattern
Implementing the factory pattern
Implementing the command pattern
Implementing the strategy pattern
Implementing the visitor pattern
Implementing the template pattern
Summary
8
Refactoring, Debugging, and Testing
Refactoring, Debugging, and Testing
Refactoring functional code
Debugging lambda expressions
Using the println method to assist debugging
Testing functional programs
Summary
9
Bringing It All Together
Bringing It All Together
Functional Zork
The game's architecture
Summary
Epilogue
Index
Index

Refactoring functional code

Refactoring code is the process of reworking the code to improve its readability and the maintainability of the program. In this section, we will examine the refactoring support provided by NetBeans and Eclipse. This support can be categorized as follows:

  • Converting anonymous inner classes to lambda expressions

  • Refactoring multiple instances of code

  • Miscellaneous refactoring support

In Chapter 2, Putting the Function in Functional Programming, we demonstrated how to convert the following anonymous inner class to a lambda expression:

    List<String> list = Arrays.asList("Huey", "Dewey", "Louie");
    list.forEach(new Consumer<String>() {
        @Override
        public void accept(String t) {
            System.out.println(t);
        }
    });

We will use this example to demonstrate refactoring.

NetBeans support for refactoring

We will examine how refactoring can be achieved in NetBeans. This IDE provides the basic functionality needed for most of the common...

Previous Section
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