Let external plugins register combat tag implementations

Remove static 'CombatTagHelper', and add a CombatTagPlugin getter to the SpawnShield class.

Author: Techcable

api/src/main/java/net/techcable/spawnshield/combattag/CombatTagPlugin.java

@@ -1,17 +1,17 @@
 /**
  * The MIT License
  * Copyright (c) 2015 Techcable
- *
+ * <p>
  * Permission is hereby granted, free of charge, to any person obtaining a copy
  * of this software and associated documentation files (the "Software"), to deal
  * in the Software without restriction, including without limitation the rights
  * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
  * copies of the Software, and to permit persons to whom the Software is
  * furnished to do so, subject to the following conditions:
- *
+ * <p>
  * The above copyright notice and this permission notice shall be included in
  * all copies or substantial portions of the Software.
- *
+ * <p>
  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
@@ -24,6 +24,7 @@
 
 import org.bukkit.entity.Entity;
 import org.bukkit.entity.Player;
+import org.bukkit.plugin.Plugin;
 
 public interface CombatTagPlugin {
 
@@ -79,4 +80,11 @@ public interface CombatTagPlugin {
      */
     public boolean isInstalled();
 
+    /**
+     * Return the plugin who owns this combat tagging instance
+     *
+     *
+     * @return the plugin
+     */
+    public Plugin getPlugin();
 }

base/src/main/java/net/techcable/spawnshield/SpawnShield.java

@@ -22,21 +22,34 @@
  */
 package net.techcable.spawnshield;
 
-import lombok.Getter;
-import net.techcable.spawnshield.combattag.CombatTagHelper;
+import lombok.*;
+
+import java.io.IOException;
+import java.lang.reflect.Constructor;
+import java.lang.reflect.InvocationTargetException;
+import java.util.Set;
+import java.util.UUID;
+import java.util.logging.Level;
+import java.util.stream.Collector;
+
+import com.google.common.collect.ImmutableList;
+
+import net.techcable.spawnshield.combattag.CombatTagPlugin;
+import net.techcable.spawnshield.combattag.MultiPluginCombatTagPlugin;
 import net.techcable.spawnshield.compat.worldguard6.WorldGuard6Plugin;
 import net.techcable.spawnshield.config.SpawnShieldConfig;
 import net.techcable.spawnshield.config.SpawnShieldMessages;
 import net.techcable.spawnshield.forcefield.ForceFieldListener;
-import net.techcable.spawnshield.tasks.ForceFieldUpdateTask;
 import net.techcable.spawnshield.tasks.KnockbackTask;
 import net.techcable.spawnshield.tasks.TeleportSafezoningTask;
 import net.techcable.techutils.TechPlugin;
+
 import org.bukkit.Bukkit;
+import org.bukkit.plugin.Plugin;
+import org.bukkit.plugin.RegisteredServiceProvider;
+import org.bukkit.plugin.ServicePriority;
 import org.bukkit.plugin.java.JavaPlugin;
-
-import java.io.IOException;
-import java.util.UUID;
+import org.reflections.Reflections;
 
 @Getter
 public class SpawnShield extends TechPlugin<SpawnShieldPlayer> {
@@ -48,16 +61,26 @@ public class SpawnShield extends TechPlugin<SpawnShieldPlayer> {
     private ForceFieldListener forceFieldListener;
     private TeleportSafezoningTask teleportSafezoningTask;
     private KnockbackTask knockbackTask;
-    private ForceFieldUpdateTask forceFieldUpdateTask;
 
     @Override
     protected void startup() {
-        Utils.info("Loading SpawnShield by Techcable");
-        if (!CombatTagHelper.isInstalled()) {
-            Utils.severe("No Combat Tagging Plugin Installed");
-            Utils.severe("Shutting down");
+        getInstance().getLogger().info("Loading SpawnShield by Techcable");
+        if (getCombatTagPlugins().isEmpty()) {
+            getInstance().getLogger().severe("No Combat Tagging Plugin Installed");
+            getInstance().getLogger().severe("Shutting down");
             setEnabled(false);
             return;
+        } else {
+            getLogger().info("Found " + getCombatTagPlugins().size() + " installed CombatTagPlugins:");
+            int i = 1;
+            for (CombatTagPlugin plugin : getCombatTagPlugins()) {
+                Plugin providingPlugin = JavaPlugin.getProvidingPlugin(plugin.getClass());
+                getLogger().info(i + ") " + plugin.getPlugin().getName());
+                if (providingPlugin != plugin.getPlugin()) {
+                    getLogger().info("\t- this is provided by " + providingPlugin.getName() + " not implemented in " + plugin.getPlugin().getName() + " itself");;
+                    getLogger().info("\t- therefore report bugs with the integration to " + Utils.getAuthors(providingPlugin) + ", not to " + Utils.getAuthors(plugin.getPlugin()));
+                }
+            }
         }
         settings = new SpawnShieldConfig(this);
         messages = new SpawnShieldMessages(this);
@@ -86,46 +109,96 @@ public int getValue() {
             });
             metrics.start();
         } catch (IOException e) {
-            Utils.warning("Unable to run metrics");
+            getInstance().getLogger().warning("Unable to run metrics");
+        }
+        if (getSettings().isDebug()) {
+            getLogger().setLevel(Level.FINE);
         }
         //Add the protection plugins
         int numPluginsAdded = 0;
         if (Bukkit.getPluginManager().isPluginEnabled("WorldGuard")) {
             String version = Bukkit.getPluginManager().getPlugin("WorldGuard").getDescription().getVersion();
             if (version.startsWith("6")) {
-                Utils.info("Worldguard 6 Detected, Activatin support");
+                getInstance().getLogger().info("Worldguard 6 Detected, Activating support");
                 WorldGuard6Plugin hook = new WorldGuard6Plugin();
                 getSettings().addProtectionPlugin(hook);
                 numPluginsAdded++;
             }
         }
         if (numPluginsAdded == 0) {
-            Utils.severe("No supported protection plugin found, shutting down");
+            getInstance().getLogger().severe("No supported protection plugin found, shutting down");
             setEnabled(false);
             return;
         }
         getCommand("spawnshield").setExecutor(new SpawnShieldExecutor());
         switch (settings.getMode()) {
             case FORCEFIELD :
-                Utils.warning("Force field mode is currently unsupported");
-                this.forceFieldListener = new ForceFieldListener();
+                this.forceFieldListener = new ForceFieldListener(this);
                 registerListener(forceFieldListener);
                 break;
             case TELEPORT :
-                teleportSafezoningTask = new TeleportSafezoningTask();
+                teleportSafezoningTask = new TeleportSafezoningTask(this);
                 teleportSafezoningTask.runTaskTimer(this, 5, 5); //Every 1/4 of a tick
                 break;
             case KNOCKBACK :
-                knockbackTask = new KnockbackTask();
+                knockbackTask = new KnockbackTask(this);
                 knockbackTask.runTaskTimer(this, 5, 5); //Every 1/4 of a tick
                 break;
             default :
-                Utils.severe("[SpawnShield] Unknown Plugin Mode");
+                getInstance().getLogger().severe("[SpawnShield] Unknown Plugin Mode");
                 setEnabled(false);
                 return;
         }
     }
 
+    public CombatTagPlugin getCombatTagPlugin() {
+        ImmutableList<CombatTagPlugin> plugins = getCombatTagPlugins();
+        switch (plugins.size()) {
+            case 0:
+                throw new IllegalStateException("No CombatTagPlugin installed!");
+            case 1:
+                return plugins.get(0);
+            default:
+                return new MultiPluginCombatTagPlugin(plugins);
+        }
+    }
+
+
+    public ImmutableList<CombatTagPlugin> getCombatTagPlugins() {
+        if (getServer().getServicesManager().getRegistrations(this).isEmpty()) {
+            // Search classpath for our own impls
+            String className = CombatTagPlugin.class.getName();
+            String packageName = className.substring(0, className.lastIndexOf('.') - 1);
+            Set<Class<? extends CombatTagPlugin>> pluginTypes = new Reflections(packageName).getSubTypesOf(CombatTagPlugin.class);
+            for (Class<? extends CombatTagPlugin> pluginType : pluginTypes) {
+                if (pluginType == MultiPluginCombatTagPlugin.class) continue;
+                CombatTagPlugin plugin;
+                try {
+                    Constructor<? extends CombatTagPlugin> c = pluginType.getConstructor();
+                    c.setAccessible(true);
+                    plugin = c.newInstance();
+                } catch (NoSuchMethodException | InstantiationException e) {
+                    continue;
+                } catch (IllegalAccessException e) {
+                    throw new RuntimeException("Unable to call setAccessible() on " + pluginType.getSimpleName());
+                } catch (InvocationTargetException e) {
+                    Throwable cause = e.getTargetException();
+                    throw new RuntimeException("new " + pluginType.getSimpleName() + "() threw an exception", cause);
+                }
+                getServer().getServicesManager().register(CombatTagPlugin.class, plugin, this, ServicePriority.Normal);
+            }
+        }
+        return getServer().getServicesManager().getRegistrations(CombatTagPlugin.class).stream()
+                .map(RegisteredServiceProvider::getProvider)
+                .filter(CombatTagPlugin::isInstalled) // Only return installed plugins :)
+                .collect(Collector.<CombatTagPlugin, ImmutableList.Builder<CombatTagPlugin>, ImmutableList<CombatTagPlugin>>of(
+                        ImmutableList::builder,
+                        ImmutableList.Builder::add,
+                        (builder1, builder2) -> builder1.addAll(builder2.build()),
+                        ImmutableList.Builder::build
+                ));
+    }
+
     @Override
     protected void shutdown() {
         if (getSettings() != null) getSettings().save();

base/src/main/java/net/techcable/spawnshield/Utils.java

@@ -23,31 +23,38 @@
 package net.techcable.spawnshield;
 
 import com.google.common.base.Preconditions;
+import com.google.common.collect.ImmutableList;
+
 import lombok.AccessLevel;
 import lombok.NoArgsConstructor;
+
+import java.util.List;
+
 import org.bukkit.Bukkit;
+import org.bukkit.plugin.Plugin;
 
 @NoArgsConstructor(access = AccessLevel.PRIVATE)
 public class Utils {
 
-    public static void severe(String error) {
-        Bukkit.getLogger().severe("[SpawnShield] " + error);
-    }
-
-    public static void warning(String error) {
-        Bukkit.getLogger().warning("[SpawnShield] " + error);
-    }
-
-    public static void debug(String msg) {
-        if (SpawnShield.getInstance().getSettings().isDebug()) {
-            info(msg);
+    public static String getAuthors(Plugin plugin) {
+        List<String> authors = plugin.getDescription().getAuthors();
+        switch (authors.size()) {
+            case 0:
+                return "unknown author";
+            case 1:
+                return authors.get(0);
+            default:
+                StringBuilder builder = new StringBuilder();
+                for (int i = 0; i < authors.size() - 1; i++) {
+                    if (i != 0) builder.append(", ");
+                    builder.append(authors.get(i));
+                }
+                builder.append(", and ");
+                builder.append(authors.get(authors.size() - 1));
+                return builder.toString();
         }
     }
 
-    public static void info(String msg) {
-        Bukkit.getLogger().info("[SpawnShield] " + msg);
-    }
-
     public static void assertMainThread() {
         Preconditions.checkState(Bukkit.isPrimaryThread(), "Should only be called on the primary thread");
     }