Feature - plugin watcher, detect file changes & reload

Common/src/main/java/net/frankheijden/serverutils/common/entities/AbstractResult.java

@@ -0,0 +1,13 @@
+package net.frankheijden.serverutils.common.entities;
+
+public interface AbstractResult {
+
+    /**
+     * Retrieves the associated message of the result
+     * and sends it to a CommandSender.
+     * @param sender The receiver.
+     * @param action The action which let to the result.
+     * @param what An associated variable.
+     */
+    void sendTo(ServerCommandSender sender, String action, String what);
+}

Common/src/main/java/net/frankheijden/serverutils/common/entities/AbstractTask.java

@@ -0,0 +1,6 @@
+package net.frankheijden.serverutils.common.entities;
+
+public abstract class AbstractTask implements Runnable {
+
+    public abstract void cancel();
+}

Common/src/main/java/net/frankheijden/serverutils/common/entities/Result.java

@@ -5,7 +5,7 @@ import net.frankheijden.serverutils.common.config.Messenger;
 /**
  * An enum containing possible results.
  */
-public enum Result {
+public enum Result implements AbstractResult {
     NOT_EXISTS,
     NOT_ENABLED,
     ALREADY_LOADED,
@@ -44,6 +44,7 @@ public enum Result {
      * @param action The action which let to the result.
      * @param what An associated variable.
      */
+    @Override
     public void sendTo(ServerCommandSender sender, String action, String what) {
         Messenger.sendMessage(sender, "serverutils." + this.name().toLowerCase(),
                 "%action%", action,

Common/src/main/java/net/frankheijden/serverutils/common/entities/ServerCommandSender.java

@@ -17,4 +17,10 @@ public interface ServerCommandSender {
      * @return Whether or not they have the permission.
      */
     boolean hasPermission(String permission);
+
+    /**
+     * Whether or not the given instance is a player.
+     * @return Boolean true or false.
+     */
+    boolean isPlayer();
 }

Common/src/main/java/net/frankheijden/serverutils/common/entities/ServerUtilsPlugin.java

@@ -15,7 +15,7 @@ public abstract class ServerUtilsPlugin {
 
     public abstract <T> AbstractPluginManager<T> getPluginManager();
 
-    public abstract AbstractTaskManager getTaskManager();
+    public abstract <T> AbstractTaskManager<T> getTaskManager();
 
     public abstract ResourceProvider getResourceProvider();
 
@@ -52,4 +52,12 @@ public abstract class ServerUtilsPlugin {
         }
         return file;
     }
+
+    public void enable() {
+
+    }
+
+    public void disable() {
+        getTaskManager().cancelAllTasks();
+    }
 }

Common/src/main/java/net/frankheijden/serverutils/common/entities/WatchResult.java

@@ -0,0 +1,24 @@
+package net.frankheijden.serverutils.common.entities;
+
+import net.frankheijden.serverutils.common.config.Messenger;
+
+public enum WatchResult implements AbstractResult {
+
+    START,
+    CHANGE,
+    NOT_WATCHING,
+    STOPPED;
+
+    /**
+     * Retrieves the associated message of the result
+     * and sends it to a CommandSender.
+     * @param sender The receiver.
+     * @param action The action which let to the result.
+     * @param what An associated variable.
+     */
+    @Override
+    public void sendTo(ServerCommandSender sender, String action, String what) {
+        Messenger.sendMessage(sender, "serverutils.watcher." + this.name().toLowerCase(),
+                "%what%", what);
+    }
+}

Common/src/main/java/net/frankheijden/serverutils/common/managers/AbstractPluginManager.java

@@ -2,10 +2,15 @@ package net.frankheijden.serverutils.common.managers;
 
 import java.io.File;
 
+import net.frankheijden.serverutils.common.ServerUtilsApp;
+import net.frankheijden.serverutils.common.entities.AbstractResult;
 import net.frankheijden.serverutils.common.entities.CloseableResult;
 import net.frankheijden.serverutils.common.entities.LoadResult;
 import net.frankheijden.serverutils.common.entities.Result;
+import net.frankheijden.serverutils.common.entities.ServerCommandSender;
+import net.frankheijden.serverutils.common.entities.WatchResult;
 import net.frankheijden.serverutils.common.providers.PluginProvider;
+import net.frankheijden.serverutils.common.tasks.PluginWatcherTask;
 
 public abstract class AbstractPluginManager<T> extends PluginProvider<T> {
 
@@ -22,4 +27,27 @@ public abstract class AbstractPluginManager<T> extends PluginProvider<T> {
     public abstract CloseableResult unloadPlugin(String pluginName);
 
     public abstract CloseableResult unloadPlugin(T plugin);
+
+    /**
+     * Starts watching the specified plugin for changes.
+     * Reloads the plugin if a change is detected.
+     * @param pluginName The plugin to watch.
+     * @return The result of the action.
+     */
+    public AbstractResult watchPlugin(ServerCommandSender sender, String pluginName) {
+        if (getPlugin(pluginName) == null) return Result.NOT_EXISTS;
+        ServerUtilsApp.getPlugin().getTaskManager()
+                .runTaskAsynchronously(pluginName, new PluginWatcherTask(sender, pluginName));
+        return WatchResult.START;
+    }
+
+    /**
+     * Stops watching the plugin for changes.
+     * @param pluginName The plugin to stop watching.
+     * @return The result of the action.
+     */
+    public AbstractResult unwatchPlugin(String pluginName) {
+        if (ServerUtilsApp.getPlugin().getTaskManager().cancelTask(pluginName)) return WatchResult.STOPPED;
+        return WatchResult.NOT_WATCHING;
+    }
 }

Common/src/main/java/net/frankheijden/serverutils/common/managers/AbstractTaskManager.java

@@ -1,8 +1,71 @@
 package net.frankheijden.serverutils.common.managers;
 
-public abstract class AbstractTaskManager {
+import java.util.ArrayList;
+import java.util.HashMap;
+import java.util.List;
+import java.util.Map;
+import java.util.function.Consumer;
+
+import net.frankheijden.serverutils.common.entities.AbstractTask;
+
+public abstract class AbstractTaskManager<T> {
+
+    private final List<T> serverTasks;
+    private final Consumer<T> taskCloser;
+    private final Map<String, AbstractTask> tasks;
+
+    /**
+     * Constructs a new TaskManager with a consumer which closes a task.
+     * @param taskCloser The consumer which will close tasks.
+     */
+    public AbstractTaskManager(Consumer<T> taskCloser) {
+        this.taskCloser = taskCloser;
+        this.serverTasks = new ArrayList<>();
+        this.tasks = new HashMap<>();
+    }
 
     public abstract void runTask(Runnable runnable);
 
+    public void runTask(String key, AbstractTask task) {
+        tasks.put(key, task);
+        runTask(task);
+    }
+
     public abstract void runTaskAsynchronously(Runnable runnable);
+
+    public void runTaskAsynchronously(String key, AbstractTask task) {
+        tasks.put(key, task);
+        runTaskAsynchronously(task);
+    }
+
+    public void addTask(T task) {
+        serverTasks.add(task);
+    }
+
+    /**
+     * Cancels a single task by key.
+     * @param key The key of the task.
+     * @return Whether or not the task existed.
+     */
+    public boolean cancelTask(String key) {
+        AbstractTask task = tasks.remove(key);
+        if (task == null) return false;
+        task.cancel();
+        return true;
+    }
+
+    /**
+     * Cancels all tasks.
+     */
+    public void cancelAllTasks() {
+        for (AbstractTask task : tasks.values()) {
+            task.cancel();
+        }
+        tasks.clear();
+
+        for (T task : serverTasks) {
+            taskCloser.accept(task);
+        }
+        serverTasks.clear();
+    }
 }

Common/src/main/java/net/frankheijden/serverutils/common/providers/PluginProvider.java

@@ -17,6 +17,10 @@ public abstract class PluginProvider<T> {
 
     public abstract File getPluginFile(T plugin);
 
+    public abstract File getPluginFile(String pluginName);
+
+    public abstract T getPlugin(String pluginName);
+
     public abstract Set<String> getCommands();
 
     /**

Common/src/main/java/net/frankheijden/serverutils/common/tasks/PluginWatcherTask.java

@@ -0,0 +1,97 @@
+package net.frankheijden.serverutils.common.tasks;
+
+import com.sun.nio.file.SensitivityWatchEventModifier;
+
+import java.io.File;
+import java.io.IOException;
+import java.nio.file.FileSystems;
+import java.nio.file.StandardWatchEventKinds;
+import java.nio.file.WatchEvent;
+import java.nio.file.WatchKey;
+import java.nio.file.WatchService;
+import java.util.concurrent.atomic.AtomicBoolean;
+
+import net.frankheijden.serverutils.common.ServerUtilsApp;
+import net.frankheijden.serverutils.common.entities.AbstractTask;
+import net.frankheijden.serverutils.common.entities.ServerCommandSender;
+import net.frankheijden.serverutils.common.entities.ServerUtilsPlugin;
+import net.frankheijden.serverutils.common.entities.WatchResult;
+import net.frankheijden.serverutils.common.managers.AbstractPluginManager;
+import net.frankheijden.serverutils.common.managers.AbstractTaskManager;
+import net.frankheijden.serverutils.common.providers.ChatProvider;
+
+public class PluginWatcherTask extends AbstractTask {
+
+    private static final WatchEvent.Kind<?>[] EVENTS = new WatchEvent.Kind[] {
+        StandardWatchEventKinds.ENTRY_CREATE,
+        StandardWatchEventKinds.ENTRY_MODIFY,
+        StandardWatchEventKinds.ENTRY_DELETE
+    };
+
+    private final ServerUtilsPlugin plugin = ServerUtilsApp.getPlugin();
+
+    @SuppressWarnings("rawtypes")
+    private final AbstractPluginManager pluginManager = plugin.getPluginManager();
+    private final ChatProvider chatProvider = plugin.getChatProvider();
+    @SuppressWarnings("rawtypes")
+    private final AbstractTaskManager taskManager = plugin.getTaskManager();
+
+    private final ServerCommandSender sender;
+    private final String pluginName;
+    private File file;
+    private final AtomicBoolean run;
+
+    /**
+     * Constructs a new PluginWatcherTask for the specified plugin.
+     * @param pluginName The name of the plugin.
+     */
+    public PluginWatcherTask(ServerCommandSender sender, String pluginName) {
+        this.sender = sender;
+        this.pluginName = pluginName;
+        this.file = pluginManager.getPluginFile(pluginName);
+        this.run = new AtomicBoolean(true);
+    }
+
+    @Override
+    public void run() {
+        try (WatchService watchService = FileSystems.getDefault().newWatchService()) {
+            File folder = pluginManager.getPluginsFolder();
+            folder.toPath().register(watchService, EVENTS, SensitivityWatchEventModifier.HIGH);
+
+            while (run.get()) {
+                WatchKey key = watchService.take();
+                for (WatchEvent<?> event : key.pollEvents()) {
+                    if (file.getName().equals(event.context().toString())) {
+                        send(WatchResult.CHANGE);
+
+                        taskManager.runTask(() -> {
+                            pluginManager.reloadPlugin(pluginName);
+                            file = pluginManager.getPluginFile(pluginName);
+                        });
+                    }
+                }
+
+                if (file == null || !key.reset()) {
+                    send(WatchResult.STOPPED);
+                    break;
+                }
+            }
+        } catch (IOException ex) {
+            ex.printStackTrace();
+        } catch (InterruptedException ignored) {
+            //
+        }
+    }
+
+    private void send(WatchResult result) {
+        result.sendTo(sender, null, pluginName);
+        if (sender.isPlayer()) {
+            result.sendTo(chatProvider.getConsoleSender(), null, pluginName);
+        }
+    }
+
+    @Override
+    public void cancel() {
+        run.set(false);
+    }
+}