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Kotlin Blueprints
Kotlin Blueprints

Kotlin Blueprints: A practical guide to building industry-grade web, mobile, and desktop applications in Kotlin using frameworks such as Spring Boot and Node.js

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Profile Icon Belagali Profile Icon Trivedi Profile Icon Akshay Chordiya
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€18.99 per month
Full star icon Full star icon Full star icon Full star icon Half star icon 4.5 (2 Ratings)
Paperback Dec 2017 260 pages 1st Edition
eBook
€8.99 €29.99
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Arrow left icon
Profile Icon Belagali Profile Icon Trivedi Profile Icon Akshay Chordiya
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€18.99 per month
Full star icon Full star icon Full star icon Full star icon Half star icon 4.5 (2 Ratings)
Paperback Dec 2017 260 pages 1st Edition
eBook
€8.99 €29.99
Paperback
€36.99
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Kotlin Blueprints

Geospatial Messenger – Spring Boot

Writing code in Kotlin is fun, thanks to its concise nature that allows writing applications with shorter, efficient, and expressive code. One of the biggest selling points of Kotlin is its excellent interoperability with Java which means it is designed to play well with the Java ecosystem; the frameworks and libraries. 

Things get really interesting and fun when Kotlin is used together with Spring Boot, which is one of the most widely used web frameworks for quickly bootstrapping and developing web applications in Java language. Spring Boot promotes convention over configuration and thus focuses on eliminating the specification of obvious choices, making the codebase expressive and concise. As we know, Kotlin's constructs also focus on expressiveness and conciseness. Hence development with Spring Boot benefits greatly from the...

Why Spring Boot?

Spring is a great web framework and one of the most popular ones in the Java world. With Spring Boot it became even better. Spring Boot prefers convention over configuration and that eliminates a lot of boilerplate code. It's easier to write configurations. As a result, it feels more lightweight, unlike Spring Framework. Spring Boot is a microservice ready platform.

In a nutshell, Spring Boot helps you to quickly bootstrap your product, and it includes helpful features to push your application to production with almost no fuss. 

Leveraging Kotlin in Spring Boot applications

Using Kotlin for the development of Spring Boot applications is beneficial. Let's look at some of the common Kotlin...

Let's build our geospatial messenger

We are going to build a geospatial messenger to understand how to build a Spring Boot application with Kotlin and how to leverage language features of Kotlin to enable faster development. We will learn how to build robust apps while having fun with the concise syntax of Kotlin.

The idea of the geospatial messenger is to provide a layer of maps to the end user where they can leave messages on a particular coordinate, which can be read by anyone accessing the website. 

Preview

The preview of the UI of the application is shown, where the current location of the user is shown with the marker (depends if the user allows accessing location in the browser) and the envelope icon in the...

Architecture

Here is the technology stack we are going to use:

  • Frontend:
    • Basic HTML
    • CSS with Bootstrap framework
    • JavaScript with a jQuery plugin
    • Open Layers: To show the map to the user
  • Backend:
    • Spring Boot
    • Kotlin
  • Database:
    • PostGIS: Extension of PostgreSQL for geospatial operations
    • Exposed: ORM for SQL operations

The following illustration is a representation of the technology stack we will use:

Setting up the IDE

We will be using IntelliJ Ultimate throughout this chapter to build the geospatial messenger application. You can use any other IDE like Eclipse or download IntelliJ Ultimate from the following link: https://www.jetbrains.com/idea/download/.

...

Setting up the build script

Build systems are software tools designed to automate the process of program compilation such as Maven, Gradle, and others. We will be using the Gradle build system for our project. 

Adding Kotlin dependency

Kotlin language is added as a Gradle dependency in the project:

    // Kotlin
compile "org.jetbrains.kotlin:kotlin-stdlib-jre8:$kotlin_version"

Adding Spring Boot dependencies

To set up the project with Spring Boot packages we need to add the following dependencies in the build.gradle file:

    // Spring
...

Coding the application

Our project is ready with required project structure and Gradle dependency and configuration. It's time to write the application code.

Frontend

The UI or frontend is made with pure HTML, CSS, and JS with jQuery.

HTML

We just have a single HTML page called index.html:

    <!DOCTYPE html>
<html>
<head>
<title>Geospatial Messenger</title>
<!-- CSS -->
<link rel="stylesheet"
href="http://openlayers.org/en/v4.3.3/css/ol.css"
type=&quot...

Why Spring Boot?


Spring is a great web framework and one of the most popular ones in the Java world. With Spring Boot it became even better. Spring Boot prefers convention over configuration and that eliminates a lot of boilerplate code. It's easier to write configurations. As a result, it feels more lightweight, unlike Spring Framework. Spring Boot is a microservice ready platform.

In a nutshell, Spring Boot helps you to quickly bootstrap your product, and it includes helpful features to push your application to production with almost no fuss. 

Leveraging Kotlin in Spring Boot applications

Using Kotlin for the development of Spring Boot applications is beneficial. Let's look at some of the common Kotlin constructs that are used for building Spring Boot applications.

Extension functions

The extension functions in Kotlin provide an easy way to add new functionality to an existing API in a non-intrusive way. Often, they are used to eliminate the need to write special utility or helper classes....

Let's build our geospatial messenger


We are going to build a geospatial messenger to understand how to build a Spring Boot application with Kotlin and how to leverage language features of Kotlin to enable faster development. We will learn how to build robust apps while having fun with the concise syntax of Kotlin.

The idea of the geospatial messenger is to provide a layer of maps to the end user where they can leave messages on a particular coordinate, which can be read by anyone accessing the website. 

Preview

The preview of the UI of the application is shown, where the current location of the user is shown with the marker (depends if the user allows accessing location in the browser) and the envelope icon in the image denotes the messages left on a given coordinate:

Features

Let's look at all the features we need to develop in our application:

  • To leave a message, the user needs to click on a location or co-ordinate of their choice, type their message in the message box and save 
  • To see an existing...

Architecture


Here is the technology stack we are going to use:

  • Frontend:
    • Basic HTML
    • CSS with Bootstrap framework
    • JavaScript with a jQuery plugin
    • Open Layers: To show the map to the user
  • Backend:
    • Spring Boot
    • Kotlin
  • Database:
    • PostGIS: Extension of PostgreSQL for geospatial operations
    • Exposed: ORM for SQL operations

The following illustration is a representation of the technology stack we will use:

Setting up the IDE

We will be using IntelliJ Ultimate throughout this chapter to build the geospatial messenger application. You can use any other IDE like Eclipse or download IntelliJ Ultimate from the following link: https://www.jetbrains.com/idea/download/.

Creating a project

Create a new project in IntelliJ, select Gradle and add the dependencies related to Spring Boot and Kotlin mentioned in the following screenshot. 

Here are the following steps:

  1. Open IntelliJ.
  2. Click File | New | Project.
  3. Select Gradle with Kotlin and web:

You can also use: https://start.spring.io to create a starter template with Spring Boot...

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Key benefits

  • Learn to build exciting and scalable Android and web applications (both the server-side and client-side parts) with your Kotlin skills
  • Dive into the great ecosystem of Kotlin frameworks and libraries through projects that you’ll build using this book
  • This project-based guide contains clear instructions to help you extend your applications across a wide domain

Description

Kotlin is a powerful language that has applications in a wide variety of fields. It is a concise, safe, interoperable, and tool-friendly language. The Android team has also announced first-class support for Kotlin, which is an added boost to the language. Kotlin’s growth is fueled through carefully designed business and technology benefits. The collection of projects demonstrates the versatility of the language and enables you to build standalone applications on your own. You’ll build comprehensive applications using the various features of Kotlin. Scale, performance, and high availability lie at the heart of the projects, and the lessons learned throughout this book. You’ll learn how to build a social media aggregator app that will help you efficiently track various feeds, develop a geospatial webservice with Kotlin and Spring Boot, build responsive web applications with Kotlin, build a REST API for a news feed reader, and build a server-side chat application with Kotlin. It also covers the various libraries and frameworks used in the projects. Through the course of building applications, you’ll not only get to grips with the various features of Kotlin, but you’ll also discover how to design and prototype professional-grade applications.

Who is this book for?

This practical guide is for programmers who are already familiar with Kotlin. If you are familiar with Kotlin and want to put your knowledge to work, then this is the book for you. Kotlin programming knowledge is a must.

What you will learn

  • See how Kotlin s power and versatility make it a great choice to create applications across various platforms, and how it delivers business and technology benefits
  • Write a robust web applications using Kotlin with Spring Boot
  • Write Android applications with ease using Kotlin
  • Write rich desktop applications in Kotlin
  • Learn how Kotlin can generate Javascript and how this can be used on client side and server side development
  • Understand how native applications can be written with Kotlin/Native
  • Learn the practical aspects of programming in each of the applications

Product Details

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Publication date, Length, Edition, Language, ISBN-13
Publication date : Dec 08, 2017
Length: 260 pages
Edition : 1st
Language : English
ISBN-13 : 9781788390804
Vendor :
Pivotal
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Product Details

Publication date : Dec 08, 2017
Length: 260 pages
Edition : 1st
Language : English
ISBN-13 : 9781788390804
Vendor :
Pivotal
Category :
Languages :
Tools :

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Table of Contents

8 Chapters
The Power of Kotlin Chevron down icon Chevron up icon
Geospatial Messenger – Spring Boot Chevron down icon Chevron up icon
Social Media Aggregator Android App Chevron down icon Chevron up icon
Weather App Using Kotlin for JavaScript Chevron down icon Chevron up icon
Chat Application with Server-Side JavaScript Generation Chevron down icon Chevron up icon
News Feed – REST API Chevron down icon Chevron up icon
CSV Reader in Kotlin Native Chevron down icon Chevron up icon
Dictionary Desktop Application - TornadoFX Chevron down icon Chevron up icon

Customer reviews

Rating distribution
Full star icon Full star icon Full star icon Full star icon Half star icon 4.5
(2 Ratings)
5 star 50%
4 star 50%
3 star 0%
2 star 0%
1 star 0%
Erik Hellman Feb 10, 2018
Full star icon Full star icon Full star icon Full star icon Full star icon 5
The speed of evolution in Kotlin makes it hard to stay up-to-date with all the latest additions. One of the best way to stay updated is to have a good set of samples and blueprints that are easy to follow. The book provides a lot of valuable examples of the right size to be useful. I highly recommend this to anyone working with Kotlin.
Amazon Verified review Amazon
Annyce Davis Jan 30, 2018
Full star icon Full star icon Full star icon Full star icon Empty star icon 4
I spent time working with Spring Boot applications a few years ago. It was nice to see how the framework has evolved to support the Kotlin language. I appreciate how the authors showed a real-world application of working with the various aspects of a web service written in Kotlin.The Social Media Android application was very easy to follow and well done. The same goes for the examples written in Kotlin that targetted JavaScript. I'm definitely going to spend some time going back through the examples and playing around with the code more!This books does a really good job of explaining the essentials of working with the Kotlin language in various contexts. I appreciate the use of several different third-party libraries to show how diverse the ecosystem is already. I would recommend you give this a read!
Amazon Verified review Amazon
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