src/main/java/bscv/asm/api/AnnotationChecker.java


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package bscv.asm.api;

import org.objectweb.asm.AnnotationVisitor;
import org.objectweb.asm.ClassVisitor;
import org.objectweb.asm.Opcodes;
import org.objectweb.asm.Type;

import java.lang.annotation.Annotation;

/**
 * ClassVisitor which checks whether a Class is annotated with
 * a specific Annotation.
 * @author Fraaz
 */
public class AnnotationChecker extends ClassVisitor {
   private boolean annotationPresent;
   private final String annotationDesc;

   public AnnotationChecker(Class<? extends Annotation> a) {
      super(Opcodes.ASM8); //hopefully lol
      this.annotationPresent = false;
      this.annotationDesc = Type.getDescriptor(a);
   }

   @Override
   public AnnotationVisitor visitAnnotation(String desc, boolean visible) {
      if (visible && desc.equals(this.annotationDesc))
         this.annotationPresent = true;
      return super.visitAnnotation(desc, visible);
      //returning null would delete our annotation, but we don't want that
      //so we jut delegate to superclass
   }

   public boolean isAnnotationPresent() {
      return this.annotationPresent;
   }
}