avoid repeating connection details

Author: emilburzo

src/main/kotlin/com/emilburzo/stirimm/stirimmwebapp/service/NewsChangeListener.kt

@@ -1,23 +1,22 @@
 package com.emilburzo.stirimm.stirimmwebapp.service
 
 import com.emilburzo.stirimm.stirimmwebapp.persistence.NewsRepository
+import com.zaxxer.hikari.HikariDataSource
 import org.postgresql.PGConnection
 import org.slf4j.LoggerFactory
-import org.springframework.beans.factory.annotation.Value
 import org.springframework.boot.context.event.ApplicationReadyEvent
 import org.springframework.context.event.EventListener
 import org.springframework.scheduling.annotation.Scheduled
 import org.springframework.stereotype.Component
 import java.sql.DriverManager
 import java.util.*
+import javax.sql.DataSource
 
 @Component
 class NewsChangeListener(
     private val newsService: NewsService,
     private val newsRepository: NewsRepository,
-    @Value("\${spring.datasource.url}") private val dbUrl: String,
-    @Value("\${spring.datasource.username}") private val dbUser: String,
-    @Value("\${spring.datasource.password}") private val dbPassword: String,
+    private val dataSource: DataSource,
 ) {
 
     private val logger = LoggerFactory.getLogger(javaClass)
@@ -31,8 +30,9 @@ class NewsChangeListener(
         newsService.refresh()
         lastKnownMaxId = newsRepository.findMaxId()
 
-        if (dbUrl.startsWith("jdbc:postgresql")) {
-            Thread(::listenLoop, "pg-notify-listener").apply {
+        val hikari = dataSource as? HikariDataSource
+        if (hikari != null && hikari.jdbcUrl.startsWith("jdbc:postgresql")) {
+            Thread({ listenLoop(hikari) }, "pg-notify-listener").apply {
                 isDaemon = true
                 start()
             }
@@ -41,21 +41,20 @@ class NewsChangeListener(
         }
     }
 
-    private fun listenLoop() {
+    private fun listenLoop(hikari: HikariDataSource) {
         while (true) {
             try {
                 val props = Properties().apply {
-                    setProperty("user", dbUser)
-                    setProperty("password", dbPassword)
+                    setProperty("user", hikari.username)
+                    setProperty("password", hikari.password ?: "")
                     setProperty("tcpKeepAlive", "true")
                 }
-                DriverManager.getConnection(dbUrl, props).use { conn ->
-                    conn.unwrap(PGConnection::class.java)
+                DriverManager.getConnection(hikari.jdbcUrl, props).use { conn ->
+                    val pgConn = conn.unwrap(PGConnection::class.java)
                     conn.createStatement().execute("LISTEN news_changed")
                     logger.info("Listening for news_changed notifications")
 
                     while (true) {
-                        val pgConn = conn.unwrap(PGConnection::class.java)
                         val notifications = pgConn.getNotifications(30_000)
                         if (notifications != null && notifications.isNotEmpty()) {
                             logger.info("Received news_changed notification, refreshing cache")