diff --git a/pom.xml b/pom.xml index f521edb..c668b11 100644 --- a/pom.xml +++ b/pom.xml @@ -5,7 +5,7 @@ de.craftinc CraftincBorderProtection jar - 0.9.9 + 1.0.0 UTF-8 diff --git a/src/main/java/de/craftinc/borderprotection/Border.java b/src/main/java/de/craftinc/borderprotection/Border.java new file mode 100644 index 0000000..33049cd --- /dev/null +++ b/src/main/java/de/craftinc/borderprotection/Border.java @@ -0,0 +1,104 @@ +package de.craftinc.borderprotection; + +import org.bukkit.Location; +import org.bukkit.World; +import org.bukkit.configuration.file.FileConfiguration; +import org.bukkit.configuration.file.YamlConfiguration; + +import java.io.File; +import java.util.HashMap; +import java.util.Map; + +public class Border +{ + private static final String dataFileName = "borders.json"; + + private Location rectPoint1; + private Location rectPoint2; + + private static String rectPoint1Name = "p1"; + private static String rectPoint2Name = "p2"; + private static String rectBordersKey = "rectBorders"; + + private static final HashMap borders = new HashMap(); + + private static File bordersFile = new File(Plugin.getPlugin().getDataFolder(), dataFileName); + private static FileConfiguration bordersFileConf = YamlConfiguration.loadConfiguration(bordersFile); + + public static HashMap getBorders() + { + return borders; + } + + public Location getRectPoint1() + { + return rectPoint1; + } + + public Location getRectPoint2() + { + return rectPoint2; + } + + @SuppressWarnings("unchecked") + public Border( Map map ) + { + try + { + rectPoint1 = LocationSerializer.deserializeLocation((Map) map.get(rectPoint1Name)); + rectPoint2 = LocationSerializer.deserializeLocation((Map) map.get(rectPoint2Name)); + + if ( rectPoint1.getWorld().equals(rectPoint2.getWorld()) ) + { + borders.put(rectPoint1.getWorld(), this); + } + else + { + throw new Exception("Border points are at different worlds."); + } + } + catch ( Exception e ) + { + Plugin.getPlugin().getLogger().severe(e.getMessage()); + } + } + + public Border( Location p1, Location p2 ) throws Exception + { + rectPoint1 = p1; + rectPoint2 = p2; + if ( rectPoint1.getWorld().equals(rectPoint2.getWorld()) ) + { + borders.put(rectPoint1.getWorld(), this); + } + else + { + throw new Exception("Border points are at different worlds."); + } + } + + + public Map serialize() + { + HashMap map = new HashMap(); + map.put(rectPoint1Name, LocationSerializer.serializeLocation(rectPoint1)); + map.put(rectPoint2Name, LocationSerializer.serializeLocation(rectPoint2)); + + return map; + } + + public static void loadBorders() + { + bordersFileConf.getList(rectBordersKey); + } + + public static void saveBorders() + { + bordersFileConf.set(rectBordersKey, borders.values()); + } + + public String toString() + { + return rectPoint1.getX() + "," + rectPoint1.getZ() + " " + rectPoint2.getX() + "," + rectPoint2.getZ(); + } +} diff --git a/src/main/java/de/craftinc/borderprotection/BorderManager.java b/src/main/java/de/craftinc/borderprotection/BorderManager.java index 27bb194..aba5881 100644 --- a/src/main/java/de/craftinc/borderprotection/BorderManager.java +++ b/src/main/java/de/craftinc/borderprotection/BorderManager.java @@ -20,9 +20,6 @@ import org.bukkit.Location; import org.bukkit.World; import org.bukkit.entity.Player; -import java.io.File; -import java.util.ArrayList; -import java.util.Arrays; import java.util.Calendar; import java.util.HashMap; @@ -34,13 +31,6 @@ public class BorderManager * ********************************************************** */ - private final String dataFileName = "data.json"; - - /** - * Borders of all Worlds. String is World.getName(). Location is one point of the border. A border - * consists of two points which create a rectangle. - */ - private HashMap> borders = null; /** * For every player save the time when he got the last borderMessage @@ -51,18 +41,14 @@ public class BorderManager * The buffer in blocks which applies when a player is teleported inside the border. 0 means the player * will be teleported directly to the border. */ - private double buffer = 0.5; + public static final double buffer = 0.5; /** * A timeout for the border message. When a player tries to cross the border and sees the border message, * the earliest possible time the message will show up again is after timeout milliseconds. */ - private Long timeout = 10000L; + public static final Long timeout = 10000L; - /** - * Serializer, which is used for loading and saving data to harddisk - */ - private Serializer serializer; /** * ********************************************************* @@ -71,9 +57,8 @@ public class BorderManager */ public BorderManager() { - // initialize Serializer and load data file - serializer = new Serializer(new File(Plugin.getPlugin().getDataFolder(), dataFileName)); - borders = serializer.loadDataFile(); + // load borders + Border.loadBorders(); } @@ -83,59 +68,21 @@ public class BorderManager * ********************************************************** */ - public Serializer getSerializer() + public void setBorder( World world, double border ) throws Exception { - return serializer; + new Border(new Location(world, border, 0, border), new Location(world, -border, 0, -border)); } - public double getBuffer() + public void setBorder( World world, String p1, String p2 ) throws Exception { - return buffer; - } - public Long getTimeout() - { - return timeout; - } + String[] coordinatesP1 = p1.split(","); + Location l1 = new Location(world, Double.parseDouble(coordinatesP1[0]), 0, Double.parseDouble(coordinatesP1[1])); - public HashMap> getBorders() - { - return borders; - } + String[] coordinatesP2 = p2.split(","); + Location l2 = new Location(world, Double.parseDouble(coordinatesP2[0]), 0, Double.parseDouble(coordinatesP2[1])); - public void setBorder( String worldName, double border ) - { - if ( borders == null ) - { - borders = new HashMap>(); - } - - World world = Plugin.getPlugin().getServer().getWorld(worldName); - - // set two points which define a square - borders.put(worldName, new ArrayList(Arrays.asList( - new Location(world, border, 0, border), - new Location(world, -border, 0, -border) - ))); - } - - public void setBorder( String worldName, String[] borderPoints ) - { - if ( borders == null ) - { - borders = new HashMap>(); - } - - ArrayList locations = new ArrayList(); - World world = Plugin.getPlugin().getServer().getWorld(worldName); - - for ( String borderPoint : borderPoints ) - { - String[] point = borderPoint.split(","); - locations.add(new Location(world, Double.parseDouble(point[0]), 0, Double.parseDouble(point[1]))); - } - - borders.put(worldName, locations); + new Border(l1, l2); } @@ -143,20 +90,20 @@ public class BorderManager * Checks if the given location is inside the border rectangle. Returns null if yes, otherwise new coordinates. * * @param location location to check - * @param borderPoints points which define the border rectangle + * @param border Border object which defines the border * @param buffer if the player will be teleported back, then he will be buffer far away * from the border he tried to cross * @return null if the player is inside, otherwise a new player location */ - public Double[] checkBorder( Location location, ArrayList borderPoints, double buffer ) + public Double[] checkBorder( Location location, Border border, double buffer ) { // New x and z: null by default Double[] newXZ = { null, null }; // check if player is withing the X borders - newXZ[0] = _checkBorder(location.getX(), borderPoints.get(0).getX(), borderPoints.get(1).getX(), buffer); + newXZ[0] = _checkBorder(location.getX(), border.getRectPoint1().getX(), border.getRectPoint2().getX(), buffer); // check if player is withing the Z borders - newXZ[1] = _checkBorder(location.getZ(), borderPoints.get(0).getZ(), borderPoints.get(1).getZ(), buffer); + newXZ[1] = _checkBorder(location.getZ(), border.getRectPoint1().getZ(), border.getRectPoint2().getZ(), buffer); // Do nothing, if no new coordinates have been calculated. if ( newXZ[0] == null && newXZ[1] == null ) @@ -212,7 +159,7 @@ public class BorderManager Long now = Calendar.getInstance().getTimeInMillis(); if ( ( lastBorderMessage.get(player.getName()) != null && - now - getTimeout() > lastBorderMessage.get(player.getName()) ) || + now - timeout > lastBorderMessage.get(player.getName()) ) || lastBorderMessage.get(player.getName()) == null ) { // show message diff --git a/src/main/java/de/craftinc/borderprotection/Commands.java b/src/main/java/de/craftinc/borderprotection/Commands.java index 8cab03a..16361bc 100644 --- a/src/main/java/de/craftinc/borderprotection/Commands.java +++ b/src/main/java/de/craftinc/borderprotection/Commands.java @@ -16,14 +16,12 @@ */ package de.craftinc.borderprotection; -import org.bukkit.Location; +import org.bukkit.World; import org.bukkit.command.Command; import org.bukkit.command.CommandExecutor; import org.bukkit.command.CommandSender; import org.bukkit.entity.Player; -import java.util.ArrayList; - public class Commands implements CommandExecutor { private BorderManager borderManager; @@ -56,45 +54,54 @@ public class Commands implements CommandExecutor // set if ( ( args.length == 2 || args.length == 3 ) && args[0].equalsIgnoreCase("set") ) { - if ( !sender.hasPermission("craftinc.borderprotection.set") ) + if ( ! sender.hasPermission("craftinc.borderprotection.set") ) { sender.sendMessage(Messages.noPermissionSet); return false; } if ( args.length == 2 ) { - borderManager.setBorder(( (Player) sender ).getWorld().getName(), Double.parseDouble(args[1])); + try + { + borderManager.setBorder(( (Player) sender ).getWorld(), Double.parseDouble(args[1])); + } + catch ( Exception e ) + { + sender.sendMessage(e.getMessage()); + } } - else if ( args.length == 3 ) + else { - String[] borderDefinition = { args[1], args[2] }; - borderManager.setBorder(( (Player) sender ).getWorld().getName(), borderDefinition); + try + { + borderManager.setBorder(( (Player) sender ).getWorld(), args[1], args[2]); + } + catch ( Exception e ) + { + sender.sendMessage(e.getMessage()); + } } // save the new border - borderManager.getSerializer().saveDataFile(borderManager.getBorders()); + Border.saveBorders(); return true; } // get if ( args.length == 1 && ( args[0].equalsIgnoreCase("get") || args[0].equalsIgnoreCase("info") ) ) { - String worldName = ( (Player) sender ).getWorld().getName(); + World world = ( (Player) sender ).getWorld(); // exit and send the player a message if no border is set - if ( borderManager.getBorders() == null || - borderManager.getBorders().get(worldName) == null ) + if ( ! Border.getBorders().containsKey(world) ) { sender.sendMessage(Messages.borderInfoNoBorderSet); return true; } - ArrayList borderPoints = borderManager.getBorders() - .get(worldName); - String borderDef = borderPoints.get(0).getX() + "," + borderPoints.get(0).getZ() + " " + - borderPoints.get(1).getX() + "," + borderPoints.get(1).getZ(); + Border border = Border.getBorders().get(world); - sender.sendMessage(Messages.borderInfo(worldName, borderDef)); + sender.sendMessage(Messages.borderInfo(world.getName(), border.toString())); return true; } } diff --git a/src/main/java/de/craftinc/borderprotection/LocationSerializer.java b/src/main/java/de/craftinc/borderprotection/LocationSerializer.java new file mode 100644 index 0000000..3834bcb --- /dev/null +++ b/src/main/java/de/craftinc/borderprotection/LocationSerializer.java @@ -0,0 +1,84 @@ +package de.craftinc.borderprotection; + +import org.bukkit.Location; +import org.bukkit.World; + +import java.util.HashMap; +import java.util.Map; + + +/** + * NOTE: We do not care about yaw and pitch for gate locations. So we won't serialize them. + */ +public class LocationSerializer +{ + protected static String worldKey = "world"; + protected static String xKey = "x"; + protected static String yKey = "y"; + protected static String zKey = "z"; + + + protected static World getWorld(String name) throws Exception + { + World world = Plugin.getPlugin().getServer().getWorld(name); + + if (world == null) { + throw new Exception("World '" + name + "' does not exists anymore! Cannot get instance!"); + } + + return world; + } + + + public static Map serializeLocation(Location l) + { + if (l == null) { + return null; + } + + Map serializedLocation = new HashMap(); + + serializedLocation.put(worldKey, l.getWorld().getName()); + serializedLocation.put(xKey, l.getX()); + serializedLocation.put(yKey, l.getY()); + serializedLocation.put(zKey, l.getZ()); + + return serializedLocation; + } + + + public static Location deserializeLocation(Map map) throws Exception + { + if (map == null) { + return null; + } + + World w = getWorld((String)map.get(worldKey)); + + + // verbose loading of coordinates (they might be Double or Integer) + Object objX = map.get(xKey); + Object objY = map.get(yKey); + Object objZ = map.get(zKey); + + double x,y,z; + + if (objX instanceof Integer) + x = (double)(Integer)objX; + else + x = (Double)objX; + + if (objY instanceof Integer) + y = (double)(Integer)objY; + else + y = (Double)objY; + + if (objZ instanceof Integer) + z = (double)(Integer)objZ; + else + z = (Double)objZ; + + + return new Location(w, x, y, z); + } +} diff --git a/src/main/java/de/craftinc/borderprotection/PlayerMoveListener.java b/src/main/java/de/craftinc/borderprotection/PlayerMoveListener.java index 3dc9098..6c11624 100644 --- a/src/main/java/de/craftinc/borderprotection/PlayerMoveListener.java +++ b/src/main/java/de/craftinc/borderprotection/PlayerMoveListener.java @@ -18,15 +18,14 @@ package de.craftinc.borderprotection; import org.bukkit.Location; import org.bukkit.Material; +import org.bukkit.World; import org.bukkit.block.Block; -import org.bukkit.entity.Player; +import org.bukkit.block.BlockFace; import org.bukkit.event.EventHandler; import org.bukkit.event.EventPriority; import org.bukkit.event.Listener; import org.bukkit.event.player.PlayerMoveEvent; -import java.util.ArrayList; - public class PlayerMoveListener implements Listener { @@ -37,11 +36,11 @@ public class PlayerMoveListener implements Listener this.borderManager = borderManager; } - private Double goUpUntilFreeSpot( Player player ) + private Double goUpUntilFreeSpot( Location newLocation ) { // go up in height until the player can stand in AIR - Block footBlock = player.getLocation().getBlock(); - Block headBlock = player.getEyeLocation().getBlock(); + Block footBlock = newLocation.getBlock(); + Block headBlock = newLocation.getBlock().getRelative(BlockFace.UP); while ( footBlock.getType() != Material.AIR || headBlock.getType() != Material.AIR ) { byte offset = 1; @@ -66,7 +65,7 @@ public class PlayerMoveListener implements Listener } // do nothing if there are no border definitions at all - if ( borderManager.getBorders() == null ) + if ( Border.getBorders().isEmpty() ) { return; } @@ -75,20 +74,20 @@ public class PlayerMoveListener implements Listener Location playerLocation = e.getPlayer().getLocation(); // world where the player is in - String worldName = e.getPlayer().getWorld().getName(); + World world= e.getPlayer().getWorld(); - // borders of this world - ArrayList borderPoints = borderManager.getBorders().get(worldName); + // border of this world + Border border = Border.getBorders().get(world); // do nothing if there are no borders for this specific world - if ( borderPoints == null ) + if ( border == null ) return; // change x or z. default: do not change Double[] newXZ; // check if player is inside the borders. null if yes, otherwise a tuple which defines the new player position - newXZ = borderManager.checkBorder(playerLocation, borderPoints, borderManager.getBuffer()); + newXZ = borderManager.checkBorder(playerLocation, border, BorderManager.buffer); // Do nothing, if no new coordinates have been calculated. if ( newXZ == null ) @@ -101,7 +100,7 @@ public class PlayerMoveListener implements Listener newXZ[1] = newXZ[1] == null ? playerLocation.getZ() : newXZ[1]; // change Y if necessary (when there is no free spot) - Double newY = goUpUntilFreeSpot(e.getPlayer()); + Double newY = goUpUntilFreeSpot(new Location(world, newXZ[0], e.getPlayer().getLocation().getY(), newXZ[1])); // teleport the player to the new X and Z coordinates e.getPlayer().teleport( diff --git a/src/main/java/de/craftinc/borderprotection/PlayerTeleportListener.java b/src/main/java/de/craftinc/borderprotection/PlayerTeleportListener.java index 11e98bc..71ee50a 100644 --- a/src/main/java/de/craftinc/borderprotection/PlayerTeleportListener.java +++ b/src/main/java/de/craftinc/borderprotection/PlayerTeleportListener.java @@ -17,13 +17,12 @@ package de.craftinc.borderprotection; import org.bukkit.Location; +import org.bukkit.World; import org.bukkit.event.EventHandler; import org.bukkit.event.EventPriority; import org.bukkit.event.Listener; import org.bukkit.event.player.PlayerTeleportEvent; -import java.util.ArrayList; - public class PlayerTeleportListener implements Listener { private BorderManager borderManager; @@ -43,7 +42,7 @@ public class PlayerTeleportListener implements Listener } // do nothing if there are no border definitions at all - if ( borderManager.getBorders() == null ) + if ( Border.getBorders().isEmpty() ) { return; } @@ -52,13 +51,13 @@ public class PlayerTeleportListener implements Listener Location targetLocation = e.getTo(); // world where the player is in - String worldName = targetLocation.getWorld().getName(); + World world = targetLocation.getWorld(); // borders of this world - ArrayList borderPoints = borderManager.getBorders().get(worldName); + Border border = Border.getBorders().get(world); // do nothing if there are no borders for this specific world - if ( borderPoints == null ) + if ( border == null ) { return; } @@ -67,7 +66,7 @@ public class PlayerTeleportListener implements Listener Double[] newXZ; // check if target is inside the borders. null if yes, otherwise a tuple which defines the new position - newXZ = borderManager.checkBorder(targetLocation, borderPoints, borderManager.getBuffer()); + newXZ = borderManager.checkBorder(targetLocation, border, BorderManager.buffer); // Cancel event, if new coordinates have been calculated. diff --git a/src/main/java/de/craftinc/borderprotection/Serializer.java b/src/main/java/de/craftinc/borderprotection/Serializer.java deleted file mode 100644 index dd9d086..0000000 --- a/src/main/java/de/craftinc/borderprotection/Serializer.java +++ /dev/null @@ -1,113 +0,0 @@ -/* CraftInc BorderProtection - Copyright (C) 2012 Paul Schulze - - This program is free software: you can redistribute it and/or modify - it under the terms of the GNU General Public License as published by - the Free Software Foundation, either version 3 of the License, or - (at your option) any later version. - - This program is distributed in the hope that it will be useful, - but WITHOUT ANY WARRANTY; without even the implied warranty of - MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the - GNU General Public License for more details. - - You should have received a copy of the GNU General Public License - along with this program. If not, see . -*/ -package de.craftinc.borderprotection; - -import org.bukkit.Location; -import org.json.simple.JSONArray; -import org.json.simple.parser.JSONParser; -import org.json.simple.parser.ParseException; - -import java.io.*; -import java.util.ArrayList; -import java.util.HashMap; - -public class Serializer -{ - private File dataFile; - - public Serializer( File dataFile ) - { - this.dataFile = dataFile; - } - - public HashMap> loadDataFile() - { - try - { - FileReader fr = new FileReader(dataFile); - BufferedReader br = new BufferedReader(fr); - StringBuilder fileContents = new StringBuilder(); - - String line; - while ( ( line = br.readLine() ) != null ) - { - fileContents.append(line); - } - - JSONParser jsonParser = new JSONParser(); - JSONArray json = (JSONArray) jsonParser.parse(fileContents.toString()); - - return Util.decodeJSON(json); - } - catch ( IOException e ) - { - if ( e instanceof FileNotFoundException ) - { - Plugin.getPlugin().getLogger().info("Data file not found."); - } - else - { - e.printStackTrace(); - } - } - catch ( ParseException e ) - { - Plugin.getPlugin().getLogger() - .severe("Could not parse json data file. When you set up a new border, the corrupt data file will be overwritten!"); - e.printStackTrace(); - } - return null; - } - - public void saveDataFile( HashMap> data ) - { - // if there is not data, do nothing and log it to console - if ( data == null ) - { - Plugin.getPlugin().getLogger().severe("Could not save data, because it is null"); - return; - } - - // create plugin directory if it doesn't exists - if ( !Plugin.getPlugin().getDataFolder().exists() ) - { - Plugin.getPlugin().getLogger().info("Creating plugin directory..."); - if ( !Plugin.getPlugin().getDataFolder().mkdir() ) - { - Plugin.getPlugin().getLogger().severe("Could not create plugin directory"); - } - else - { - Plugin.getPlugin().getLogger().info("Plugin directory created successfully"); - } - } - - JSONArray json = Util.encodeJSON(data); - - // Write to file - try - { - FileWriter fw = new FileWriter(dataFile); - fw.write(json.toJSONString()); - fw.close(); - } - catch ( IOException e ) - { - e.printStackTrace(); - } - } -} diff --git a/src/main/java/de/craftinc/borderprotection/Util.java b/src/main/java/de/craftinc/borderprotection/Util.java deleted file mode 100644 index b38c0bd..0000000 --- a/src/main/java/de/craftinc/borderprotection/Util.java +++ /dev/null @@ -1,106 +0,0 @@ -/* CraftInc BorderProtection - Copyright (C) 2012 Paul Schulze - - This program is free software: you can redistribute it and/or modify - it under the terms of the GNU General Public License as published by - the Free Software Foundation, either version 3 of the License, or - (at your option) any later version. - - This program is distributed in the hope that it will be useful, - but WITHOUT ANY WARRANTY; without even the implied warranty of - MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the - GNU General Public License for more details. - - You should have received a copy of the GNU General Public License - along with this program. If not, see . -*/ -package de.craftinc.borderprotection; - -import org.bukkit.Bukkit; -import org.bukkit.Location; -import org.json.simple.JSONArray; -import org.json.simple.JSONObject; - -import java.util.ArrayList; -import java.util.HashMap; - -public class Util -{ - public static HashMap> decodeJSON( JSONArray json ) - { - HashMap> data = new HashMap>(); - - for ( Object jsonEntry : json.toArray() ) - { - JSONObject j = (JSONObject) jsonEntry; -// // check if border for this world is enabled. continue if not -// String enabled = (String) j.get("enabled"); -// if (enabled != "1") { -// continue; -// } - String worldname = (String) j.get("worldname"); - ArrayList locations = new ArrayList(); - JSONArray borderPoints = (JSONArray) j.get("borderPoints"); - - for ( Object pointObj : borderPoints ) - { - JSONArray point = (JSONArray) pointObj; - - locations - .add(new Location(Bukkit.getWorld(worldname), (Double) point.get(0), 0, (Double) point.get(1))); - } - - data.put(worldname, locations); - } - - if ( data.size() > 0 ) - { - return data; - } - - return null; - } - - public static JSONArray encodeJSON( HashMap> data ) - { - JSONArray json = new JSONArray(); - int i = 0; - for ( ArrayList border : data.values() ) - { - - // add point 1 as json array - JSONArray point1 = new JSONArray(); - point1.add(0, border.get(0).getX()); - point1.add(1, border.get(0).getZ()); - - // add point 2 as json array - JSONArray point2 = new JSONArray(); - point2.add(0, border.get(1).getX()); - point2.add(1, border.get(1).getZ()); - - // add both points to points json array - JSONArray points = new JSONArray(); - points.add(point1); - points.add(point2); - - // Add points and worldname to world json object - JSONObject borderOfAWorld = new JSONObject(); - try - { - borderOfAWorld.put("worldname", border.get(0).getWorld().getName()); - borderOfAWorld.put("borderPoints", points); - json.add(i, borderOfAWorld); - i++; - } - catch ( NullPointerException e ) - { - if ( border.get(0).getWorld() == null ) - { - Plugin.getPlugin().getLogger() - .warning("A world is null. Ignoring this border (not saving this border)."); - } - } - } - return json; - } -} diff --git a/src/main/resources/plugin.yml b/src/main/resources/plugin.yml index cf4aabb..281cabb 100644 --- a/src/main/resources/plugin.yml +++ b/src/main/resources/plugin.yml @@ -14,9 +14,9 @@ # You should have received a copy of the GNU General Public License # along with this program. If not, see . -name: CraftincBorderProtection +name: Craft Inc. BorderProtection main: de.craftinc.borderprotection.Plugin -version: 0.9.9 +version: 1.0.0 author: ddidderr website: http://www.craftinc.de/plugins/borderprotection @@ -27,8 +27,8 @@ commands: permissions: craftinc.borderprotection.set: - default: false + default: op description: Allows to set the border for a world. craftinc.borderprotection.ignoreborders: - default: false + default: op description: Allows to be everywhere on the map (ignoring the borders).