Add Spring Boot DataFrame example with CSV data sources and web integ…

…ration

Introduce a comprehensive Spring Boot example (`springboot-dataframe-web`) showcasing annotated CSV-based data source initialization, web controllers, Thymeleaf templates, and sample data files. The example includes customer and sales reports with sorting and filtering functionalities, leveraging DataFrame operations and Spring Boot features.

examples/idea-examples/springboot-dataframe-web/build.gradle.kts

@@ -0,0 +1,31 @@
+import org.jetbrains.kotlin.gradle.dsl.JvmTarget
+import org.jetbrains.kotlin.gradle.tasks.KotlinCompile
+
+plugins {
+    kotlin("jvm")
+    id("org.springframework.boot") version "3.3.2"
+    id("io.spring.dependency-management") version "1.1.6"
+    application
+}
+
+repositories {
+    mavenCentral()
+    mavenLocal() // in case of local dataframe development
+}
+
+application {
+    mainClass.set("org.jetbrains.kotlinx.dataframe.examples.springboot.SpringbootDataframeApplicationKt")
+}
+
+dependencies {
+    implementation(project(":dataframe-spring"))
+    implementation("org.springframework.boot:spring-boot-starter-web")
+    implementation("org.springframework.boot:spring-boot-starter-thymeleaf")
+    runtimeOnly("org.springframework.boot:spring-boot-devtools")
+}
+
+java.sourceCompatibility = JavaVersion.VERSION_17
+
+tasks.withType<KotlinCompile> {
+    compilerOptions.jvmTarget = JvmTarget.JVM_17
+}

examples/idea-examples/springboot-dataframe-web/src/main/kotlin/org/jetbrains/kotlinx/dataframe/examples/springboot/SpringbootDataframeApplication.kt

@@ -0,0 +1,11 @@
+package org.jetbrains.kotlinx.dataframe.examples.springboot
+
+import org.springframework.boot.autoconfigure.SpringBootApplication
+import org.springframework.boot.runApplication
+
+@SpringBootApplication
+class SpringbootDataframeApplication
+
+fun main(args: Array<String>) {
+    runApplication<SpringbootDataframeApplication>(*args)
+}

examples/idea-examples/springboot-dataframe-web/src/main/kotlin/org/jetbrains/kotlinx/dataframe/examples/springboot/config/DataSources.kt

@@ -0,0 +1,14 @@
+package org.jetbrains.kotlinx.dataframe.examples.springboot.config
+
+import org.jetbrains.kotlinx.dataframe.DataFrame
+import org.jetbrains.kotlinx.dataframe.spring.annotations.CsvDataSource
+import org.springframework.stereotype.Component
+
+@Component
+class DataSources {
+    @CsvDataSource(file = "data/customers.csv")
+    lateinit var customers: DataFrame<*>
+
+    @CsvDataSource(file = "data/sales.csv")
+    lateinit var sales: DataFrame<*>
+}

examples/idea-examples/springboot-dataframe-web/src/main/kotlin/org/jetbrains/kotlinx/dataframe/examples/springboot/service/ReportService.kt

@@ -0,0 +1,20 @@
+package org.jetbrains.kotlinx.dataframe.examples.springboot.service
+
+import org.jetbrains.kotlinx.dataframe.DataFrame
+import org.jetbrains.kotlinx.dataframe.api.*
+import org.jetbrains.kotlinx.dataframe.examples.springboot.config.DataSources
+import org.springframework.stereotype.Service
+
+@Service
+class ReportService(
+    private val dataSources: DataSources
+) {
+    fun customersSortedByName(): DataFrame<*> =
+        dataSources.customers.sortBy("name")
+
+    fun customersFilteredByCountry(country: String): DataFrame<*> =
+        dataSources.customers.filter { it["country"].toString().equals(country, ignoreCase = true) }
+
+    fun salesSortedByValueDesc(): DataFrame<*> =
+        dataSources.sales.sortByDesc("value")
+}

examples/idea-examples/springboot-dataframe-web/src/main/kotlin/org/jetbrains/kotlinx/dataframe/examples/springboot/web/ReportController.kt

@@ -0,0 +1,42 @@
+package org.jetbrains.kotlinx.dataframe.examples.springboot.web
+
+import org.jetbrains.kotlinx.dataframe.examples.springboot.service.ReportService
+import org.springframework.stereotype.Controller
+import org.springframework.ui.Model
+import org.springframework.web.bind.annotation.GetMapping
+import org.springframework.web.bind.annotation.RequestParam
+
+@Controller
+class ReportController(
+    private val reportService: ReportService
+) {
+    @GetMapping("/")
+    fun index(): String = "index"
+
+    @GetMapping("/customers")
+    fun customers(model: Model): String {
+        val df = reportService.customersSortedByName()
+        model.addAttribute("table", df.toTableView())
+        model.addAttribute("title", "Customers (sorted by name)")
+        return "table"
+    }
+
+    @GetMapping("/customers/filter")
+    fun customersFilter(
+        @RequestParam("country") country: String,
+        model: Model
+    ): String {
+        val df = reportService.customersFilteredByCountry(country)
+        model.addAttribute("table", df.toTableView())
+        model.addAttribute("title", "Customers from $country")
+        return "table"
+    }
+
+    @GetMapping("/sales")
+    fun sales(model: Model): String {
+        val df = reportService.salesSortedByValueDesc()
+        model.addAttribute("table", df.toTableView())
+        model.addAttribute("title", "Sales (sorted by value desc)")
+        return "table"
+    }
+}

examples/idea-examples/springboot-dataframe-web/src/main/kotlin/org/jetbrains/kotlinx/dataframe/examples/springboot/web/ViewModels.kt

@@ -0,0 +1,15 @@
+package org.jetbrains.kotlinx.dataframe.examples.springboot.web
+
+import org.jetbrains.kotlinx.dataframe.DataFrame
+import org.jetbrains.kotlinx.dataframe.api.*
+
+data class TableView(
+    val headers: List<String>,
+    val rows: List<List<String>>
+)
+
+fun DataFrame<*>.toTableView(): TableView {
+    val headers = this.columnNames()
+    val rows = this.rows().map { row -> headers.map { h -> row[h].toString() } }
+    return TableView(headers, rows)
+}

examples/idea-examples/springboot-dataframe-web/src/main/resources/application.properties

@@ -0,0 +1 @@
+spring.thymeleaf.cache=false

examples/idea-examples/springboot-dataframe-web/src/main/resources/data/customers.csv

@@ -0,0 +1,13 @@
+id,name,country,email
+1,Alice Johnson,USA,[email protected]
+2,Bob Smith,Canada,[email protected]
+3,Charlie Davis,USA,[email protected]
+4,Diana Evans,UK,[email protected]
+5,Edward Wilson,USA,[email protected]
+6,Fiona Brown,Australia,[email protected]
+7,George Miller,Germany,[email protected]
+8,Helen Clark,USA,[email protected]
+9,Ian Thompson,Ireland,[email protected]
+10,Julia Roberts,USA,[email protected]
+11,Kevin Lee,Canada,[email protected]
+12,Linda Perez,Spain,[email protected]

examples/idea-examples/springboot-dataframe-web/src/main/resources/data/sales.csv

@@ -0,0 +1,13 @@
+sale_id,customer_id,product,value,date
+1001,1,Laptop,1200.50,2025-01-05
+1002,2,Phone,799.99,2025-01-10
+1003,3,Tablet,450.00,2025-02-14
+1004,4,Headphones,149.99,2025-02-20
+1005,5,Monitor,299.49,2025-03-01
+1006,6,Keyboard,89.99,2025-03-12
+1007,7,Mouse,49.95,2025-03-15
+1008,8,Smartwatch,199.00,2025-04-01
+1009,9,Camera,650.75,2025-04-12
+1010,10,Printer,220.00,2025-04-20
+1011,11,Speaker,130.00,2025-05-02
+1012,12,Router,99.99,2025-05-10

examples/idea-examples/springboot-dataframe-web/src/main/resources/templates/index.html

@@ -0,0 +1,27 @@
+<!DOCTYPE html>
+<html xmlns:th="http://www.thymeleaf.org">
+<head>
+    <meta charset="UTF-8" />
+    <title>DataFrame Spring Boot Demo</title>
+    <style>
+        body { font-family: Arial, sans-serif; margin: 2rem; }
+        .btn { display: inline-block; margin: .25rem; padding: .5rem 1rem; background: #1e88e5; color: #fff; text-decoration: none; border-radius: 4px; }
+        .btn.secondary { background: #43a047; }
+        .btn.warn { background: #fb8c00; }
+    </style>
+</head>
+<body>
+<h1>Reports</h1>
+<p>Choose one of the reports below:</p>
+<div>
+    <a class="btn" href="/customers">Customers (sort by name)</a>
+    <a class="btn" href="/sales">Sales (sort by value desc)</a>
+</div>
+<hr/>
+<h2>Filter Customers by Country</h2>
+<form action="/customers/filter" method="get">
+    <label>Country: <input type="text" name="country" placeholder="USA" required/></label>
+    <button class="btn secondary" type="submit">Filter</button>
+</form>
+</body>
+</html>

examples/idea-examples/springboot-dataframe-web/src/main/resources/templates/table.html

@@ -0,0 +1,30 @@
+<!DOCTYPE html>
+<html xmlns:th="http://www.thymeleaf.org">
+<head>
+    <meta charset="UTF-8" />
+    <title th:text="${title}">Table</title>
+    <style>
+        body { font-family: Arial, sans-serif; margin: 2rem; }
+        table { border-collapse: collapse; width: 100%; }
+        th, td { border: 1px solid #ddd; padding: 8px; }
+        th { background: #f5f5f5; text-align: left; }
+        .btn { display: inline-block; margin: .25rem; padding: .5rem 1rem; background: #1e88e5; color: #fff; text-decoration: none; border-radius: 4px; }
+    </style>
+</head>
+<body>
+<a class="btn" href="/">Back</a>
+<h2 th:text="${title}">Table</h2>
+<table>
+    <thead>
+    <tr>
+        <th th:each="h : ${table.headers}" th:text="${h}">Header</th>
+    </tr>
+    </thead>
+    <tbody>
+    <tr th:each="row : ${table.rows}">
+        <td th:each="cell : ${row}" th:text="${cell}">cell</td>
+    </tr>
+    </tbody>
+</table>
+</body>
+</html>

settings.gradle.kts

@@ -31,6 +31,7 @@ include("examples:idea-examples:movies")
 include("examples:idea-examples:youtube")
 include("examples:idea-examples:json")
 include("examples:idea-examples:unsupported-data-sources")
+include("examples:idea-examples:springboot-dataframe-web")
 includeBuild("examples/kotlin-dataframe-plugin-example")
 
 val jupyterApiTCRepo: String by settings