Added ability for OptionalArg to return a default value.

use CommandContext#getArgumentOrElse() to get a default value if none are present.

Author: RealMangorage

src/main/java/org/mangorage/mangobotcore/api/command/v1/CommandContext.java

@@ -1,6 +1,7 @@
 package org.mangorage.mangobotcore.api.command.v1;
 
 import org.mangorage.mangobotcore.api.command.v1.argument.Argument;
+import org.mangorage.mangobotcore.api.command.v1.argument.OptionalArg;
 
 public final class CommandContext<C> {
 
@@ -40,6 +41,11 @@ public <T> T getArgument(Argument<T> argument) {
         return rawValue.value();
     }
 
+    public <T> T getArgumentOrElse(OptionalArg<T> optionalArgument) {
+        final var result = getArgument(optionalArgument);
+        return result == null ? optionalArgument.getDefaultValue() : result;
+    }
+
     public String peek() {
         return index < arguments.length ? arguments[index] : null;
     }

src/main/java/org/mangorage/mangobotcore/api/command/v1/argument/OptionalArg.java

@@ -1,7 +1,14 @@
 package org.mangorage.mangobotcore.api.command.v1.argument;
 
 public class OptionalArg<T> extends Argument<T> {
-    public OptionalArg(String name, String description, ArgumentType<T> argumentType) {
+    private final T defaultValue;
+
+    public OptionalArg(String name, String description, ArgumentType<T> argumentType, T defaultValue) {
         super(name, description, argumentType);
+        this.defaultValue = defaultValue;
+    }
+
+    public T getDefaultValue() {
+        return defaultValue;
     }
 }