package net.florianschoppmann.java.reflect;
   
   import javax.lang.model.element.Modifier;
   import java.util.Set;
   
   abstract class ElementImpl extends AnnotatedConstructImpl implements ReflectionElement {
       private boolean finished = false;
   
       @Override
      public final Set<Modifier> getModifiers() {
          throw new UnsupportedOperationException(String.format(
              "Modifiers not currently supported by %s.", ReflectionTypes.class
          ));
      }
  
      final void requireFinished() {
          if (!finished) {
              throw new IllegalStateException(String.format("Instance of %s used before it was ready.", getClass()));
          }
      }
  
      abstract void finishDerivedFromElement(MirrorContext mirrorContext);
  
      final void finish(MirrorContext mirrorContext) {
          if (finished) {
              throw new IllegalStateException(String.format(
                  "Attempt to finish instance of %s more than once.", getClass()
              ));
          }
  
          finished = true;
          finishDerivedFromElement(mirrorContext);
      }
  }