Added Java plugin loader + a plugin manager

By: Dinnerbone <dinnerbone@dinnerbone.com>

paper-api/src/org/bukkit/plugin/PluginManager.java

@@ -0,0 +1,82 @@
+
+package org.bukkit.plugin;
+
+import java.io.File;
+import java.util.ArrayList;
+import java.util.HashMap;
+import java.util.List;
+import java.util.Set;
+import java.util.regex.Matcher;
+import org.bukkit.Server;
+import java.util.regex.Pattern;
+
+/**
+ * Handles all plugin management from the Server
+ */
+public final class PluginManager {
+    private final Server server;
+    private final HashMap<Pattern, PluginLoader> fileAssociations = new HashMap<Pattern, PluginLoader>();
+
+    public PluginManager(Server instance) {
+        server = instance;
+    }
+
+    /**
+     * Registers the specified plugin loader
+     *
+     * @param loader PluginLoader to register
+     */
+    public void RegisterInterface(PluginLoader loader) {
+        Pattern[] patterns = loader.getPluginFileFilters();
+
+        for (Pattern pattern : patterns) {
+            fileAssociations.put(pattern, loader);
+        }
+    }
+
+    /**
+     * Loads the plugins contained within the specified directory
+     *
+     * @param directory Directory to check for plugins
+     * @return A list of all plugins loaded
+     */
+    public Plugin[] loadPlugins(File directory) {
+        List<Plugin> result = new ArrayList<Plugin>();
+        File[] files = directory.listFiles();
+
+        for (File file : files) {
+            Plugin plugin = loadPlugin(file);
+            
+            if (plugin != null) {
+                result.add(plugin);
+            }
+        }
+
+        return (Plugin[])result.toArray();
+    }
+
+    /**
+     * Loads the plugin in the specified file
+     *
+     * File must be valid according to the current enabled Plugin interfaces
+     *
+     * @param file File containing the plugin to load
+     * @return The Plugin loaded, or null if it was invalid
+     */
+    public Plugin loadPlugin(File file) {
+        Set<Pattern> filters = fileAssociations.keySet();
+        Plugin result = null;
+
+        for (Pattern filter : filters) {
+            String name = file.getName();
+            Matcher match = filter.matcher(name);
+
+            if (match.find()) {
+                PluginLoader loader = fileAssociations.get(filter);
+                result = loader.loadPlugin(file);
+            }
+        }
+
+        return result;
+    }
+}