Changes to sql structure

- changed SqliteUpdateManager to SqliteManager
- added methods to execute sql with values and callback to the SqliteManager
- added auto close of statements
- switched to establishing a connection only when sql should be executed

src/main/kotlin/net/trivernis/chunkmaster/Chunkmaster.kt

@@ -3,7 +3,7 @@ package net.trivernis.chunkmaster
 import io.papermc.lib.PaperLib
 import net.trivernis.chunkmaster.commands.*
 import net.trivernis.chunkmaster.lib.generation.GenerationManager
-import net.trivernis.chunkmaster.lib.SqlUpdateManager
+import net.trivernis.chunkmaster.lib.SqliteManager
 import org.bstats.bukkit.Metrics
 import org.bukkit.plugin.java.JavaPlugin
 import org.bukkit.scheduler.BukkitTask
@@ -12,8 +12,7 @@ import java.sql.Connection
 import java.sql.DriverManager
 
 class Chunkmaster: JavaPlugin() {
-    lateinit var sqliteConnection: Connection
-    var dbname: String? = null
+    lateinit var sqliteManager: SqliteManager
     lateinit var generationManager: GenerationManager
     private lateinit var tpsTask: BukkitTask
     var mspt = 50L      // keep track of the milliseconds per tick
@@ -51,7 +50,6 @@ class Chunkmaster: JavaPlugin() {
     override fun onDisable() {
         logger.info("Stopping all generation tasks...")
         generationManager.stopAll()
-        sqliteConnection.close()
     }
 
     /**
@@ -76,13 +74,8 @@ class Chunkmaster: JavaPlugin() {
     private fun initDatabase() {
         logger.info("Initializing Database...")
         try {
-            Class.forName("org.sqlite.JDBC")
-            sqliteConnection = DriverManager.getConnection("jdbc:sqlite:${dataFolder.absolutePath}/chunkmaster.db")
-            logger.info("Database connection established.")
-
-            val updateManager = SqlUpdateManager(sqliteConnection, this)
-            updateManager.checkUpdate()
-            updateManager.performUpdate()
+            this.sqliteManager = SqliteManager( this)
+            sqliteManager.init()
             logger.info("Database fully initialized.")
         } catch(e: Exception) {
             logger.warning("Failed to init database: ${e.message}")

src/main/kotlin/net/trivernis/chunkmaster/lib/SqliteManager.kt

@@ -2,10 +2,14 @@ package net.trivernis.chunkmaster.lib
 
 import net.trivernis.chunkmaster.Chunkmaster
 import org.apache.commons.lang.exception.ExceptionUtils
+import org.sqlite.SQLiteConnection
 import java.lang.Exception
 import java.sql.Connection
+import java.sql.DriverManager
+import java.sql.PreparedStatement
+import java.sql.ResultSet
 
-class SqlUpdateManager(private val connnection: Connection, private val chunkmaster: Chunkmaster) {
+class SqliteManager(private val chunkmaster: Chunkmaster) {
     private val tables = listOf(
         Pair(
             "generation_tasks",
@@ -23,11 +27,33 @@ class SqlUpdateManager(private val connnection: Connection, private val chunkmas
     private val needUpdate = HashSet<Pair<String, Pair<String, String>>>()
     private val needCreation = HashSet<String>()
 
+    /**
+     * Returns the connection to the database
+     */
+    fun getConnection(): Connection? {
+        try {
+            Class.forName("org.sqlite.JDBC")
+            return DriverManager.getConnection("jdbc:sqlite:${chunkmaster.dataFolder.absolutePath}/chunkmaster.db")
+        } catch (e: Exception) {
+            chunkmaster.logger.severe("Could not get database connection.")
+            chunkmaster.logger.severe(e.message)
+        }
+        return null
+    }
+
+    /**
+     * Checks for and performs an update
+     */
+    fun init() {
+        this.checkUpdate()
+        this.performUpdate()
+    }
+
     /**
      * Checks which tables need an update or creation.
      */
-    fun checkUpdate() {
-        val meta = connnection.metaData
+    private fun checkUpdate() {
+        val meta = getConnection()!!.metaData
 
         for (table in tables) {
             val resTables = meta.getTables(null, null, table.first, null)
@@ -38,6 +64,7 @@ class SqlUpdateManager(private val connnection: Connection, private val chunkmas
                     if (!resColumn.next()) {
                         needUpdate.add(Pair(table.first, column))
                     }
+                    resColumn.close()
                 }
             } else {
                 needCreation.add(table.first)
@@ -46,10 +73,32 @@ class SqlUpdateManager(private val connnection: Connection, private val chunkmas
         }
     }
 
+    /**
+     * Executes a sql statement on the database.
+     */
+    fun executeStatement(sql: String, values: HashMap<Int, Any>, callback: ((ResultSet) -> Unit)?) {
+        val connection = getConnection()
+        if (connection != null) {
+            val statement = connection.prepareStatement(sql)
+            for (parameterValue in values) {
+                statement.setObject(parameterValue.key, parameterValue.value)
+            }
+            statement.execute()
+            val res = statement.resultSet
+            if (callback != null) {
+                callback(res)
+            }
+            statement.close()
+            connection.close()
+        } else {
+            chunkmaster.logger.severe("Could not execute sql $sql. No database connection established.")
+        }
+    }
+
     /**
      * Creates or updates tables that needed an update.
      */
-    fun performUpdate() {
+    private fun performUpdate() {
         for (table in needCreation) {
             try {
                 var tableDef = "CREATE TABLE IF NOT EXISTS $table ("
@@ -59,21 +108,17 @@ class SqlUpdateManager(private val connnection: Connection, private val chunkmas
                 }
                 tableDef = tableDef.substringBeforeLast(",") + ");"
                 chunkmaster.logger.info("Creating table $table with definition $tableDef")
-                val stmt = connnection.prepareStatement(tableDef)
-                stmt.execute()
-                stmt.close()
-            } catch (err: Exception) {
+                executeStatement(tableDef, HashMap(), null)
+            } catch (e: Exception) {
                 chunkmaster.logger.severe("Error creating table $table.")
-                chunkmaster.logger.severe(err.message)
-                chunkmaster.logger.info(ExceptionUtils.getStackTrace(err));
+                chunkmaster.logger.severe(e.message)
+                chunkmaster.logger.info(ExceptionUtils.getStackTrace(e))
             }
         }
         for (table in needUpdate) {
             val updateSql = "ALTER TABLE ${table.first} ADD COLUMN ${table.second.first} ${table.second.second}"
             try {
-                val stmt = connnection.prepareStatement(updateSql)
-                stmt.execute()
-                stmt.close()
+                executeStatement(updateSql, HashMap(), null)
                 chunkmaster.logger.info("Updated table ${table.first} with sql $updateSql")
             } catch (e: Exception) {
                 chunkmaster.logger.severe("Failed to update table ${table.first} with sql $updateSql")

src/main/kotlin/net/trivernis/chunkmaster/lib/generation/GenerationManager.kt

@@ -2,11 +2,8 @@ package net.trivernis.chunkmaster.lib.generation
 
 import io.papermc.lib.PaperLib
 import net.trivernis.chunkmaster.Chunkmaster
-import org.bukkit.Chunk
 import org.bukkit.Server
 import org.bukkit.World
-import java.lang.Exception
-import java.lang.NullPointerException
 
 class GenerationManager(private val chunkmaster: Chunkmaster, private val server: Server) {
 
@@ -31,35 +28,37 @@ class GenerationManager(private val chunkmaster: Chunkmaster, private val server
             val centerChunk = ChunkCoordinates(world.spawnLocation.chunk.x, world.spawnLocation.chunk.z)
             val generationTask = createGenerationTask(world, centerChunk, centerChunk, stopAfter)
 
-            val insertStatement = chunkmaster.sqliteConnection.prepareStatement(
+            chunkmaster.sqliteManager.executeStatement(
                 """
-            INSERT INTO generation_tasks (center_x, center_z, last_x, last_z, world, stop_after)
-            values (?, ?, ?, ?, ?, ?)
-            """
+                INSERT INTO generation_tasks (center_x, center_z, last_x, last_z, world, stop_after)
+                values (?, ?, ?, ?, ?, ?)
+                """,
+                HashMap(
+                    mapOf(
+                        1 to centerChunk.x,
+                        2 to centerChunk.z,
+                        3 to centerChunk.x,
+                        4 to centerChunk.z,
+                        5 to world.name,
+                        6 to stopAfter
+                    )
+                ),
+                null
             )
-            insertStatement.setInt(1, centerChunk.x)
-            insertStatement.setInt(2, centerChunk.z)
-            insertStatement.setInt(3, centerChunk.x)
-            insertStatement.setInt(4, centerChunk.z)
-            insertStatement.setString(5, world.name)
-            insertStatement.setInt(6, stopAfter)
-            insertStatement.execute()
 
-            val getIdStatement = chunkmaster.sqliteConnection.prepareStatement(
+            var id = 0
+            chunkmaster.sqliteManager.executeStatement(
                 """
             SELECT id FROM generation_tasks ORDER BY id DESC LIMIT 1
-        """.trimIndent()
-            )
-            getIdStatement.execute()
-            val result = getIdStatement.resultSet
-            result.next()
-            val id: Int = result.getInt("id")
-
-            insertStatement.close()
-            getIdStatement.close()
+        """.trimIndent(),
+                HashMap()
+            ) {
+                it.next()
+                id = it.getInt("id")
+            }
 
             generationTask.onEndReached {
-                chunkmaster.logger.info("Task #${id} finished after ${generationTask.count} chunks.")
+                chunkmaster.logger.info("Task #${id} finished after ${it.count} chunks.")
                 removeTask(id)
             }
 
@@ -115,14 +114,13 @@ class GenerationManager(private val chunkmaster: Chunkmaster, private val server
         }
         if (taskEntry != null) {
             taskEntry.cancel()
-            val deleteTask = chunkmaster.sqliteConnection.prepareStatement(
+            chunkmaster.sqliteManager.executeStatement(
                 """
                 DELETE FROM generation_tasks WHERE id = ?;
-            """.trimIndent()
+            """.trimIndent(),
+                HashMap(mapOf(1 to taskEntry.id)),
+                null
             )
-            deleteTask.setInt(1, taskEntry.id)
-            deleteTask.execute()
-            deleteTask.close()
 
             if (taskEntry is RunningTaskEntry) {
                 if (taskEntry.task.isCancelled) {
@@ -173,24 +171,24 @@ class GenerationManager(private val chunkmaster: Chunkmaster, private val server
      * Starts all generation tasks.
      */
     fun startAll() {
-        val savedTasksStatement = chunkmaster.sqliteConnection.prepareStatement("SELECT * FROM generation_tasks")
-        savedTasksStatement.execute()
-        val res = savedTasksStatement.resultSet
-        while (res.next()) {
-            try {
-                val id = res.getInt("id")
-                val world = server.getWorld(res.getString("world"))
-                val center = ChunkCoordinates(res.getInt("center_x"), res.getInt("center_z"))
-                val last = ChunkCoordinates(res.getInt("last_x"), res.getInt("last_z"))
-                val stopAfter = res.getInt("stop_after")
-                if (this.tasks.find { it.id == id } == null) {
-                    resumeTask(world!!, center, last, id, stopAfter)
+        chunkmaster.sqliteManager.executeStatement("SELECT * FROM generation_tasks", HashMap()) {
+            val res = it
+            while (res.next()) {
+                try {
+                    val id = res.getInt("id")
+                    val world = server.getWorld(res.getString("world"))
+                    val center = ChunkCoordinates(res.getInt("center_x"), res.getInt("center_z"))
+                    val last = ChunkCoordinates(res.getInt("last_x"), res.getInt("last_z"))
+                    val stopAfter = res.getInt("stop_after")
+                    if (this.tasks.find { it.id == id } == null) {
+                        resumeTask(world!!, center, last, id, stopAfter)
+                    }
+                } catch (error: NullPointerException) {
+                    chunkmaster.logger.severe("Failed to load Task ${res.getInt("id")}.")
                 }
-            } catch (error: NullPointerException) {
-                chunkmaster.logger.severe("Failed to load Task ${res.getInt("id")}.")
             }
         }
-        savedTasksStatement.close()
+
         if (tasks.isNotEmpty()) {
             chunkmaster.logger.info("${tasks.size} saved tasks loaded.")
         }
@@ -226,22 +224,21 @@ class GenerationManager(private val chunkmaster: Chunkmaster, private val server
                 chunkmaster.logger.info(
                     """Task #${task.id} running for "${genTask.world.name}".
                     |Progress ${task.generationTask.count} chunks
-                    |${if (task.generationTask.stopAfter > 0) "(${"%.2f".format((task.generationTask.count.toDouble() /
-                            task.generationTask.stopAfter.toDouble()) * 100)}%)" else ""}.
+                    |${if (task.generationTask.stopAfter > 0) "(${"%.2f".format(
+                        (task.generationTask.count.toDouble() /
+                                task.generationTask.stopAfter.toDouble()) * 100
+                    )}%)" else ""}.
                     | Speed: ${"%.1f".format(task.generationSpeed)} chunks/sec,
                     |Last Chunk: ${genTask.lastChunk.x}, ${genTask.lastChunk.z}""".trimMargin("|").replace('\n', ' ')
                 )
-                val updateStatement = chunkmaster.sqliteConnection.prepareStatement(
+                chunkmaster.sqliteManager.executeStatement(
                     """
                     UPDATE generation_tasks SET last_x = ?, last_z = ?
                     WHERE id = ?
-                    """.trimIndent()
+                    """.trimIndent(),
+                    HashMap(mapOf(1 to genTask.lastChunk.x, 2 to genTask.lastChunk.z, 3 to task.id)),
+                    null
                 )
-                updateStatement.setInt(1, genTask.lastChunk.x)
-                updateStatement.setInt(2, genTask.lastChunk.z)
-                updateStatement.setInt(3, task.id)
-                updateStatement.execute()
-                updateStatement.close()
             } catch (error: Exception) {
                 chunkmaster.logger.warning("Exception when saving task progress ${error.message}")
             }

src/main/kotlin/net/trivernis/chunkmaster/lib/generation/GenerationTask.kt

@@ -25,7 +25,7 @@ abstract class GenerationTask(plugin: Chunkmaster, centerChunk: ChunkCoordinates
     protected val maxLoadedChunks = plugin.config.getInt("generation.max-loaded-chunks")
     protected val chunksPerStep = plugin.config.getInt("generation.chunks-per-step")
 
-    protected var endReachedCallback: (() -> Unit)? = null
+    protected var endReachedCallback: ((GenerationTask) -> Unit)? = null
         private set
 
     abstract override fun run()
@@ -58,7 +58,7 @@ abstract class GenerationTask(plugin: Chunkmaster, centerChunk: ChunkCoordinates
     /**
      * Registers end reached callback
      */
-    fun onEndReached(cb: () -> Unit) {
+    fun onEndReached(cb: (GenerationTask) -> Unit) {
         endReachedCallback = cb
     }
 }

src/main/kotlin/net/trivernis/chunkmaster/lib/generation/GenerationTaskPaper.kt

@@ -38,7 +38,7 @@ class GenerationTaskPaper(
             } else if (pendingChunks.size < maxPendingChunks) {   // if more than 10 chunks are pending, wait.
                 if (borderReached()) {
                     endReached = true
-                    endReachedCallback?.invoke()
+                    endReachedCallback?.invoke(this)
                     return
                 }
 

src/main/kotlin/net/trivernis/chunkmaster/lib/generation/GenerationTaskSpigot.kt

@@ -33,7 +33,7 @@ class GenerationTaskSpigot(
             } else {
                 if (borderReached()) {
                     endReached = true
-                    endReachedCallback?.invoke()
+                    endReachedCallback?.invoke(this)
                     return
                 }