Sample project to start off with my presentation.
- Java interoperability
- Type inference
- Smart cast
- Method references
- inline if-else and try-catch
- Expression body methods
- Default closed classes
- Null safety
- Default parameters and named parameters
- Infix methods
- Extension functions
- String templates
- Compile time constants using
const - Lateinit and Delegated properties
- Operator overloading
- Arrays
- Collections
- Object expressions and declarations (Singleton, anonymous objects etc.)
- Range expressions
- Data classes
- Higher-Order Functions and Lambdas
$ http http://localhost:8080/petsReturn a List of all existing hardcoded pets.
Example result:
[
{
"age": 3,
"breed": "Doggo",
"color": "ORANGE",
"id": 1,
"name": "Capy",
"size": "SMALL"
},
{
"age": 4,
"breed": "Kitty",
"color": "BLACK",
"hasFur": true,
"id": 2,
"name": "Tom",
"size": "MEDIUM"
}
]$ http http://localhost:8080/pets/dogsReturn a List of all existing hardcoded dogs.
Example result:
[
{
"age": 3,
"breed": "Doggo",
"color": "ORANGE",
"id": 1,
"name": "Capy",
"size": "SMALL"
}
]$ http http://localhost:8080/pets/catsReturn a List of all existing hardcoded cats.
Example result:
[
{
"age": 4,
"breed": "Kitty",
"color": "BLACK",
"hasFur": true,
"id": 2,
"name": "Tom",
"size": "MEDIUM"
}
]$ http POST http://localhost:8080/pets/dog id:=100 name="Dogger" age:=14 breed="Dogger" color="WHITE" size="SMALL"Post a new dog in the pet array
$ http POST http://localhost:8080/pets/cat id:=100 name="Tommy" age:=5 breed="Kitty" color="BLACK" size="SMALL"
hasFur:=truePost a new cat in the pet array
$ # install sdkman
$ curl -s https://get.sdkman.io | bash
$ # install kotlin
$ sdk install kotlin $ # Start in console
$ kotlinc
Welcome to Kotlin version 1.2.10 (JRE 1.8.0_45-b14)
Type :help for help, :quit for quit
>>> // Run simple command
>>> println("Hello World")
>>> // Exit
>>> :quit$ # Write the simplest script prossible
$ echo 'println("Hello World")' >> SimpleScript.kts
$ # Run example
$ kotlinc -script SimpleScript.kts$ # Write the simplest program possible
$ echo 'fun main(args: Array<String>) = println("Hello World")' >> HelloWorld.kt
$ # generate jar
$ kotlinc HelloWorld.kt -include-runtime -d hello-world.jar
$ # run program
$ java -jar hello-world.jar-
Clone this repository from GitHub and run
mvn spring-boot:runin the console to show nice banner -
Present current project and show
curlexamples -
Add
kotlinsupport using IDEAProject Structure -> Modules -> Add Kotlin
Tools -> Kotlin -> Configure Kotlin in Project
this will add the following in the maven pom file
<project>
<properties>
<!-- ... OTHER PROPERTIES ... -->
<kotlin.version>1.2.10</kotlin.version>
</properties>
<dependencies>
<!-- ... OTHER DEPENDECIES ... -->
<!-- Target java version 1.8 (other: 1.6, 1.7) -->
<dependency>
<groupId>org.jetbrains.kotlin</groupId>
<artifactId>kotlin-stdlib-jdk8</artifactId>
<version>${kotlin.version}</version>
</dependency>
<!-- LATER EDIT: For jackson -->
<dependency>
<groupId>com.fasterxml.jackson.module</groupId>
<artifactId>jackson-module-kotlin</artifactId>
</dependency>
<!-- LATER EDIT: Make classes default open for spring to do it's job -->
<dependency>
<groupId>org.jetbrains.kotlin</groupId>
<artifactId>kotlin-maven-allopen</artifactId>
<version>${kotlin.version}</version>
</dependency>
<!-- Kotlin test framework -->
<dependency>
<groupId>org.jetbrains.kotlin</groupId>
<artifactId>kotlin-test</artifactId>
<version>${kotlin.version}</version>
<scope>test</scope>
</dependency>
</dependencies>
<build>
<plugins>
<!-- ... OTHER PLUGINS ... -->
<plugin>
<groupId>org.jetbrains.kotlin</groupId>
<artifactId>kotlin-maven-plugin</artifactId>
<version>${kotlin.version}</version>
<executions>
<execution>
<id>compile</id>
<phase>compile</phase>
<goals>
<goal>compile</goal>
</goals>
</execution>
<execution>
<id>test-compile</id>
<phase>test-compile</phase>
<goals>
<goal>test-compile</goal>
</goals>
</execution>
</executions>
<configuration>
<jvmTarget>1.8</jvmTarget>
<!-- LATER EDIT: To help spring with kotlin -->
<compilerPlugins>
<plugin>spring</plugin>
</compilerPlugins>
</configuration>
</plugin>
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-compiler-plugin</artifactId>
<executions>
<execution>
<id>compile</id>
<phase>compile</phase>
<goals>
<goal>compile</goal>
</goals>
</execution>
<execution>
<id>testCompile</id>
<phase>test-compile</phase>
<goals>
<goal>testCompile</goal>
</goals>
</execution>
</executions>
</plugin>
</plugins>
</build>
</project>-
Create
kotlindirectory and mark as source root. Build project. -
For kotlin and spring integration we must add the spring-kotlin plugin.
-
For Jackson Kotlin classes support please add
com.fasterxml.jackson.module:jackson-module-kotlinto the classpath.
This project is a start off project to present the power of Kotlin.
We will follow a pattern to be able to give an example for some of Kotlin's new features.