[Bael 1687] - Spring Data Reactive Mongo DB microservice in Kotlin

algorithms/README.md

@@ -17,3 +17,6 @@
 - [How to Calculate Levenshtein Distance in Java?](http://www.baeldung.com/java-levenshtein-distance)
 - [How to Find the Kth Largest Element in Java](http://www.baeldung.com/java-kth-largest-element)
 - [Multi-Swarm Optimization Algorithm in Java](http://www.baeldung.com/java-multi-swarm-algorithm)
+- [A Maze Solver in Java](http://www.baeldung.com/java-solve-maze)
+- [Create a Sudoku Solver in Java](http://www.baeldung.com/java-sudoku)
+- [Displaying Money Amounts in Words](http://www.baeldung.com/java-money-into-words)

spring-data-5-reactive/pom.xml

@@ -0,0 +1,124 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<project xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns="http://maven.apache.org/POM/4.0.0"
+         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
+    <modelVersion>4.0.0</modelVersion>
+
+    <groupId>com.baeldung</groupId>
+    <artifactId>spring-5-data-reactive</artifactId>
+    <version>0.0.1-SNAPSHOT</version>
+    <packaging>jar</packaging>
+
+    <name>Spring-5-data-reactive</name>
+    <description>Spring-5-data-reactive with Springboot 2.0.1</description>
+
+    <parent>
+        <groupId>org.springframework.boot</groupId>
+        <artifactId>spring-boot-starter-parent</artifactId>
+        <version>2.0.1.RELEASE</version>
+        <relativePath/> <!-- lookup parent from repository -->
+    </parent>
+
+    <properties>
+        <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
+        <project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding>
+        <java.version>1.8</java.version>
+        <kotlin.version>1.2.20</kotlin.version>
+    </properties>
+
+    <dependencies>
+        <dependency>
+            <groupId>org.springframework.boot</groupId>
+            <artifactId>spring-boot-starter-data-mongodb-reactive</artifactId>
+        </dependency>
+        <dependency>
+            <groupId>org.springframework.boot</groupId>
+            <artifactId>spring-boot-starter-web</artifactId>
+        </dependency>
+        <dependency>
+            <groupId>javax.ws.rs</groupId>
+            <artifactId>javax.ws.rs-api</artifactId>
+            <version>2.1</version>
+        </dependency>
+        <dependency>
+            <groupId>com.fasterxml.jackson.module</groupId>
+            <artifactId>jackson-module-kotlin</artifactId>
+        </dependency>
+        <dependency>
+            <groupId>org.jetbrains.kotlin</groupId>
+            <artifactId>kotlin-stdlib-jdk8</artifactId>
+        </dependency>
+        <dependency>
+            <groupId>org.jetbrains.kotlin</groupId>
+            <artifactId>kotlin-reflect</artifactId>
+        </dependency>
+        <dependency>
+            <groupId>org.projectlombok</groupId>
+            <artifactId>lombok</artifactId>
+        </dependency>
+        <dependency>
+            <groupId>io.projectreactor</groupId>
+            <artifactId>reactor-test</artifactId>
+            <scope>test</scope>
+        </dependency>
+        <dependency>
+            <groupId>org.jetbrains.kotlin</groupId>
+            <artifactId>kotlin-stdlib-jdk8</artifactId>
+            <version>${kotlin.version}</version>
+        </dependency>
+    </dependencies>
+
+    <repositories>
+        <repository>
+            <id>spring-libs-snapshot</id>
+            <name>Spring Snapshot Repository</name>
+            <url>http://repo.spring.io/libs-snapshot</url>
+        </repository>
+    </repositories>
+
+    <build>
+        <sourceDirectory>src/main/kotlin</sourceDirectory>
+        <plugins>
+            <plugin>
+                <groupId>org.springframework.boot</groupId>
+                <artifactId>spring-boot-maven-plugin</artifactId>
+            </plugin>
+            <plugin>
+                <artifactId>kotlin-maven-plugin</artifactId>
+                <version>${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>
+                <groupId>org.jetbrains.kotlin</groupId>
+                <configuration>
+                    <args>
+                        <arg>-Xjsr305=strict</arg>
+                    </args>
+                    <compilerPlugins>
+                        <plugin>spring</plugin>
+                    </compilerPlugins>
+                    <jvmTarget>1.8</jvmTarget>
+                </configuration>
+                <dependencies>
+                    <dependency>
+                        <groupId>org.jetbrains.kotlin</groupId>
+                        <artifactId>kotlin-maven-allopen</artifactId>
+                        <version>${kotlin.version}</version>
+                    </dependency>
+                </dependencies>
+            </plugin>
+        </plugins>
+    </build>
+</project>

spring-data-5-reactive/src/main/kotlin/com/baeldung/Application.kt

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+package org.jetbrains.kotlin.demo
+
+import org.springframework.boot.SpringApplication
+import org.springframework.boot.autoconfigure.SpringBootApplication
+
+@SpringBootApplication
+class Application
+
+fun main(args: Array<String>) {
+    SpringApplication.run(Application::class.java, *args)
+}
+

spring-data-5-reactive/src/main/kotlin/com/baeldung/Event.kt

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+package com.baeldung
+
+import org.springframework.data.mongodb.core.mapping.Document
+
+@Document
+data class Event(val id: String, val name: String)

spring-data-5-reactive/src/main/kotlin/com/baeldung/EventRepository.kt

@@ -0,0 +1,5 @@
+package com.baeldung
+
+import org.springframework.data.mongodb.repository.ReactiveMongoRepository
+
+interface EventRepository : ReactiveMongoRepository<Event, String>

spring-data-5-reactive/src/main/kotlin/com/baeldung/MongoConfig.kt

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+package com.baeldung
+
+import com.mongodb.reactivestreams.client.MongoClient
+import com.mongodb.reactivestreams.client.MongoClients
+import org.springframework.context.annotation.Bean
+import org.springframework.context.annotation.Configuration
+import org.springframework.data.mongodb.config.AbstractReactiveMongoConfiguration
+import org.springframework.data.mongodb.core.ReactiveMongoTemplate
+import org.springframework.data.mongodb.repository.config.EnableReactiveMongoRepositories
+
+
+@Configuration
+@EnableReactiveMongoRepositories(basePackageClasses = arrayOf(EventRepository::class))
+class MongoConfig : AbstractReactiveMongoConfiguration() {
+
+    override fun reactiveMongoClient(): com.mongodb.reactivestreams.client.MongoClient {
+        return mongoClient()
+    }
+
+    @Bean
+    fun mongoClient(): MongoClient {
+        return MongoClients.create()
+    }
+
+    override fun getDatabaseName(): String {
+        return "mongoDatabase"
+    }
+
+    @Bean
+    override fun reactiveMongoTemplate(): ReactiveMongoTemplate {
+        return ReactiveMongoTemplate(mongoClient(), databaseName)
+    }
+}

spring-data-5-reactive/src/main/kotlin/com/baeldung/SendEmitter.kt

@@ -0,0 +1,43 @@
+package com.baeldung
+
+import org.springframework.web.bind.annotation.GetMapping
+import org.springframework.web.bind.annotation.RequestParam
+import org.springframework.web.bind.annotation.RestController
+import org.springframework.web.servlet.mvc.method.annotation.SseEmitter
+import reactor.core.publisher.Flux
+import reactor.core.publisher.Mono
+import java.util.*
+import javax.ws.rs.core.MediaType
+
+
+@RestController
+class SendEmitter(val eventRepository: EventRepository) {
+
+    private var emitter = SseEmitter()
+
+    /**
+     * Save and send an SSE to all subscribed clients
+     */
+    @GetMapping("/saveEvent")
+    fun executeExample(@RequestParam("eventName") eventName: String): Flux<Event> {
+        // Create new event
+        var event = Event(UUID.randomUUID().toString(), eventName)
+        // Save event
+        var stream = eventRepository.saveAll(Mono.just(event))
+        // Send event
+        emitter.send(SseEmitter.event().data(event))
+        // Return SSE
+        return stream
+    }
+
+    /**
+     * Receive SSEs
+     */
+    @GetMapping(value = "/receiveChanges")
+    fun handle(): SseEmitter {
+        // Create new emitter
+        this.emitter = SseEmitter()
+        // Return SSE
+        return emitter
+    }
+}

spring-data-5-reactive/src/main/resources/static/index.html

@@ -0,0 +1,33 @@
+<html>
+<body>
+
+<form method="get" action="/saveEvent">
+    <input type="text" name="eventName">
+    <button type="submit">Save new event</button>
+</form>
+
+
+<!-- Here will be painted each new received Server-Sent event's content-->
+<div id="content"></div>
+
+<script>
+    var source = new EventSource("receiveChanges");
+
+    source.addEventListener('message', function (e) {
+        console.log('New message is received');
+        const index = JSON.parse(e.data);
+        const content = "New event added: " + index.name + "<br>";
+        document.getElementById("content").innerHTML += content;
+    }, false);
+    source.addEventListener('open', function(e) {
+        console.log('The connection has been opened');
+    }, false);
+    source.addEventListener('error', function(e) {
+        if (e.readyState == EventSource.CLOSED){
+            console.log('The connection has been closed');
+        }
+    }, false);
+
+</script>
+</body>
+<html>