Plugin <=> CommandSystem interaction.

src/main/java/net/pingex/dcf/commands/AnnotatedCommand.java

@@ -0,0 +1,39 @@
+package net.pingex.dcf.commands;
+
+import java.lang.annotation.ElementType;
+import java.lang.annotation.Retention;
+import java.lang.annotation.RetentionPolicy;
+import java.lang.annotation.Target;
+
+/**
+ * Indicated a method which is in fact a command
+ */
+@Retention(RetentionPolicy.RUNTIME)
+@Target(ElementType.METHOD)
+public @interface AnnotatedCommand
+{
+	/**
+	 * Main name of the command
+	 */
+	String name();
+
+	/**
+	 * Command can also be called using the following list of aliases
+	 */
+	String[] aliases() default {};
+
+	/**
+	 * Description of the command.
+	 */
+	String description() default Command.Defaults.DESCRIPTION;
+
+	/**
+	 * Is the command enabled ? Can it be invoked ?
+	 */
+	boolean isEnabled() default Command.Defaults.IS_ENABLED;
+
+	/**
+	 * Command usage help
+	 */
+	String usage() default Command.Defaults.USAGE;
+}

src/main/java/net/pingex/dcf/commands/Command.java

@@ -1,5 +1,6 @@
 package net.pingex.dcf.commands;
 
+import java.lang.reflect.Method;
 import java.util.Arrays;
 import java.util.Collections;
 import java.util.List;
@@ -141,12 +142,23 @@ public abstract class Command implements ICommandExecutor
 			return new Command(name, aliases, description, isEnabled, usage)
 			{
 				@Override
-				public void execute(List<String> arguments)
+				public void execute(List<String> arguments) throws Throwable
 				{
 					toExecute.execute(arguments);
 				}
 			};
 		}
+
+		/**
+		 * Build a new Command using a method and a target object (for use with annotated command)
+		 * @param target The method which needs to be invoked
+		 * @param invokable The matching object
+		 * @return Built command.
+		 */
+		public Command build(Method target, Object invokable)
+		{
+			return build(arguments -> target.invoke(invokable));
+		}
 	}
 
 	/**
@@ -159,6 +171,21 @@ public abstract class Command implements ICommandExecutor
 		return new Builder(name);
 	}
 
+	/**
+	 * Create a new command object from an annotated method
+	 * @param target Target method
+	 * @return A new created command built from the method, or `null` if the method is not a valid command.
+	 */
+	public static Command buildFromAnnotatedCommand(AnnotatedCommand meta, Method target, Object invokable)
+	{
+		return builder(meta.name())
+				.aliases(Arrays.asList(meta.aliases()))
+				.description(meta.description())
+				.enabled(meta.isEnabled())
+				.usage(meta.usage())
+				.build(target, invokable);
+	}
+
 	public String getName()
 	{
 		return name;

src/main/java/net/pingex/dcf/commands/CommandHandler.java

@@ -3,9 +3,11 @@ package net.pingex.dcf.commands;
 import net.pingex.dcf.commands.parser.BasicParser;
 import net.pingex.dcf.commands.parser.ICommandParser;
 import net.pingex.dcf.commands.parser.ParserException;
+import net.pingex.dcf.modularity.PluginWrapper;
 import org.apache.logging.log4j.LogManager;
 import org.apache.logging.log4j.Logger;
 import sx.blah.discord.handle.impl.events.MessageReceivedEvent;
+import java.lang.reflect.Method;
 import java.util.List;
 
 /**
@@ -41,7 +43,42 @@ public class CommandHandler
 			return; // Not a command
 		}
 		LOGGER.debug("Attempting to run command {} by user #{}.", command, event.getMessage().getAuthor().getID());
+	}
+
+	/**
+	 * Registers a plugin's commands, if any
+	 * @param pluginWrapper Target plugin
+	 */
+	public static void registerPlugin(PluginWrapper pluginWrapper)
+	{
+		LOGGER.debug("Registering commands for plugin {}.", pluginWrapper.getId());
 
+		// Raw commands
+		if(IWithCommands.class.isAssignableFrom(pluginWrapper.getInstance().getClass()))
+		{
+			LOGGER.debug("Plugin has commands (raw commands).");
+			((IWithCommands) pluginWrapper.getInstance()).getCommands().forEach(CommandRegistry::registerCommand);
+		}
 
+		// Annotated commands
+		if(IWithAnnotatedCommands.class.isAssignableFrom(pluginWrapper.getInstance().getClass()))
+		{
+			LOGGER.debug("Plugin has commands (annotated commands).");
+			((IWithAnnotatedCommands) pluginWrapper.getInstance()).getAnnotatedObjects().forEach(e ->
+			{
+				for(Method i : e.getClass().getMethods())
+					if(i.isAnnotationPresent(AnnotatedCommand.class))
+						CommandRegistry.registerCommand(Command.buildFromAnnotatedCommand(i.getAnnotation(AnnotatedCommand.class), i, e));
+			});
+		}
+	}
+
+	/**
+	 * Unregisters a plugin's commands, if any
+	 * @param pluginWrapper Target plugin
+	 */
+	public static void unregisterPlugin(PluginWrapper pluginWrapper)
+	{
+		LOGGER.debug("Removing commands for plugin {}.", pluginWrapper.getId());
 	}
 }

src/main/java/net/pingex/dcf/commands/ICommandExecutor.java

@@ -8,5 +8,5 @@ import java.util.List;
 @FunctionalInterface
 public interface ICommandExecutor
 {
-	void execute(List<String> arguments);
+	void execute(List<String> arguments) throws Throwable;
 }

src/main/java/net/pingex/dcf/commands/IWithAnnotatedCommands.java

@@ -0,0 +1,16 @@
+package net.pingex.dcf.commands;
+
+import java.util.Set;
+
+/**
+ * Indicates a plugin which can run commands (using annotated commands)
+ */
+@FunctionalInterface
+public interface IWithAnnotatedCommands
+{
+	/**
+	 * Gives all annotated commands for this plugin.
+	 * @return A set of objects which contains annotated commands.
+	 */
+	Set<Object> getAnnotatedObjects();
+}

src/main/java/net/pingex/dcf/commands/IWithCommands.java

@@ -0,0 +1,16 @@
+package net.pingex.dcf.commands;
+
+import java.util.Set;
+
+/**
+ * Indicates a plugin which can run commands (using commands object)
+ */
+@FunctionalInterface
+public interface IWithCommands
+{
+	/**
+	 * Give all commands
+	 * @return ALL THE COMMANDS \o/
+	 */
+	Set<Command> getCommands();
+}