src/Annotations/ValidLength.java

@@ -0,0 +1,11 @@
+package Annotations;
+
+import java.lang.annotation.ElementType;
+import java.lang.annotation.Retention;
+import java.lang.annotation.RetentionPolicy;
+import java.lang.annotation.Target;
+
+@Target(ElementType.FIELD)
+@Retention(RetentionPolicy.RUNTIME)
+public @interface ValidLength {
+}

src/Characters/Character.java

@@ -1,5 +1,6 @@
 package Characters;
 
+import Annotations.ValidLength;
 import Entity.Entity;
 import Items.Item;
 
@@ -25,6 +26,8 @@ public abstract class Character extends Entity implements IMovable, IFeelable, I
 
   private final Gender gender;
   private Entity position;
+
+  @ValidLength
   private String currentState = "";
   protected Feels feel;
   protected Item itemInHand;
@@ -62,6 +65,7 @@ public abstract class Character extends Entity implements IMovable, IFeelable, I
 
   protected final void setPosition(Entity obj) {
     this.position = obj;
+    this.validateFields();
   }
 
   public final String getState() {
@@ -70,6 +74,7 @@ public abstract class Character extends Entity implements IMovable, IFeelable, I
 
   protected final void setState(String state) {
     this.currentState = state;
+    this.validateFields();
   }
 
   @Override
@@ -89,4 +94,34 @@ public abstract class Character extends Entity implements IMovable, IFeelable, I
   public int hashCode() {
     return Objects.hash(this.name, this.gender);
   }
+
+  private void validateFields() {
+    for (java.lang.reflect.Field field : Character.class.getDeclaredFields()) {
+      if (field.isAnnotationPresent(ValidLength.class)) {
+        String value = getValueForField(this, field);
+        if (value.length() < 3 || value.length() > 20) {
+          setValueForField(this, field, "unknown");
+        }
+      }
+    }
+  }
+
+  private static String getValueForField(Object obj, java.lang.reflect.Field field) {
+    try {
+      field.setAccessible(true);
+      return (String) field.get(obj);
+    } catch (IllegalAccessException e) {
+      e.printStackTrace();
+    }
+    return null;
+  }
+
+  private static void setValueForField(Object obj, java.lang.reflect.Field field, String value) {
+    try {
+      field.setAccessible(true);
+      field.set(obj, value);
+    } catch (IllegalAccessException e) {
+      e.printStackTrace();
+    }
+  }
 }