Commands can throw CommandExceptions

src/org/yaaic/command/BaseCommand.java

@@ -38,8 +38,9 @@ public abstract class BaseCommand
 	 * @param server The server object
 	 * @param channel The channel object or null if no channel is selected
 	 * @param service The service with all server connections
+	 * @throws CommandException if command couldn't be executed
 	 */
-	public abstract void execute(String[] params, Server server, Channel channel, IRCService service);
+	public abstract void execute(String[] params, Server server, Channel channel, IRCService service) throws CommandException;
 	
 	/**
 	 * Get the usage description for this command
@@ -47,13 +48,4 @@ public abstract class BaseCommand
 	 * @return The usage description
 	 */
 	public abstract String getUsage();
-
-	/**
-	 * How much params does this command need?
-	 * 
-	 * Default: 0
-	 * 
-	 * @return The number of params needed
-	 */
-	public abstract int needsParams();
 }

src/org/yaaic/command/CommandException.java

@@ -0,0 +1,20 @@
+package org.yaaic.command;
+
+/**
+ * The CommandException is thrown on command execution if the
+ * command couldn't be executed due to invalid params
+ * 
+ * @author Sebastian Kaspari
+ */
+public class CommandException extends Throwable
+{
+	private static final long serialVersionUID = -8317993941455253288L;
+	
+	/**
+	 * Create a new CommandException object
+	 */
+	public CommandException(String message)
+	{
+		super(message);
+	}
+}

src/org/yaaic/command/CommandParser.java

@@ -28,6 +28,7 @@ import org.yaaic.model.Channel;
 import org.yaaic.model.Message;
 import org.yaaic.model.Server;
 
+import android.R.color;
 import android.content.Intent;
 
 /**
@@ -90,14 +91,18 @@ public class CommandParser
 		
 		if (isCommand(type)) {
 			BaseCommand command = commands.get(type);
-			if (command.needsParams() > 0 && params.length - 1 == command.needsParams()) {
+			try {
 				command.execute(params, server, channel, service);
-			} else {
+			} catch(CommandException e) {
 				// Wrong number of params
 				if (channel != null) {
-					Message message = new Message("Usage of " + type + ": " + command.getUsage());
+					Message errorMessage = new Message(type + ": " + e.getMessage());
-					message.setColor(Message.COLOR_RED);
+					errorMessage.setColor(Message.COLOR_RED);
-					channel.addMessage(message);
+					channel.addMessage(errorMessage);
+					
+					Message usageMessage = new Message("Usage of " + type + ": " + command.getUsage());
+					//usageMessage.setColor(Message.COLOR_RED);
+					channel.addMessage(usageMessage);
 					
 					Intent intent = new Intent(Broadcast.CHANNEL_MESSAGE);
 					intent.putExtra(Broadcast.EXTRA_SERVER, server.getId());

src/org/yaaic/command/NickCommand.java

@@ -35,9 +35,13 @@ public class NickCommand extends BaseCommand
 	 * Execute /nick
 	 */
 	@Override
-	public void execute(String[] params, Server server, Channel channel, IRCService service)
+	public void execute(String[] params, Server server, Channel channel, IRCService service) throws CommandException 
 	{
+		if (params.length == 2) {
 			service.getConnection(server.getId()).changeNick(params[1]);
+		} else {
+			throw new CommandException("Invalid number of params");
+		}
 	}
 	
 	/**
@@ -48,14 +52,4 @@ public class NickCommand extends BaseCommand
 	{
 		return "/nick nickname";
 	}
-
-	/**
-	 * Number of params needed (1)
-	 */
-	@Override
-	public int needsParams()
-	{
-		return 1;
-	}
-	
 }