Add API in Argument

SpigotCore_Main/src/de/steamwar/commandn/Argument.java

@@ -24,22 +24,28 @@ package de.steamwar.commandn;
 import org.bukkit.command.CommandSender;
 
 import java.util.List;
+import java.util.function.BiPredicate;
 
 public interface Argument<T> {
 
-    T parse(CommandSender sender, String arg);
+    T parse(String arg) throws InvalidArgumentException;
+    void checkConstraints(CommandSender sender, T argument) throws InvalidArgumentException;
+
     List<String> tabComplete(CommandSender sender, String arg) throws InvalidArgumentException;
+    default BiPredicate<String, String> tabCompleteFilter() {
+        return String::startsWith;
+    }
 
     abstract class IntArgument implements Argument<Integer> {
         @Override
-        public Integer parse(CommandSender sender, String arg) {
+        public Integer parse(String arg) {
             return Integer.parseInt(arg);
         }
     }
 
     abstract class DoubleArgument implements Argument<Double> {
         @Override
-        public Double parse(CommandSender sender, String arg) {
+        public Double parse(String arg) {
             return Double.parseDouble(arg);
         }
     }