com.google.gwt.dev.shell.rewrite.HasAnnotation Maven / Gradle / Ivy
/*
* Copyright 2009 Google Inc.
*
* Licensed under the Apache License, Version 2.0 (the "License"); you may not
* use this file except in compliance with the License. You may obtain a copy of
* the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
* WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
* License for the specific language governing permissions and limitations under
* the License.
*/
package com.google.gwt.dev.shell.rewrite;
import com.google.gwt.dev.javac.asmbridge.EmptyVisitor;
import org.objectweb.asm.AnnotationVisitor;
import org.objectweb.asm.ClassReader;
import org.objectweb.asm.ClassVisitor;
import org.objectweb.asm.Opcodes;
import org.objectweb.asm.Type;
import java.lang.annotation.Annotation;
/**
* A simple ClassAdapter that determines if a specific annotation is declared on
* a type (ignoring any annotatons that may be present on supertypes or
* superinterfaces).
*/
public class HasAnnotation extends ClassVisitor {
/**
* A utility method to determine if the class defined in
* classBytes has a particular annotation.
*
* @param classBytes the class's bytecode
* @param annotation the type of annotation to look for
* @return true if the class defined in classBytes
* possesses the desired annotation
*/
public static boolean hasAnnotation(byte[] classBytes,
Class annotation) {
HasAnnotation v = new HasAnnotation(new EmptyVisitor(), annotation);
new ClassReader(classBytes).accept(v, ClassReader.SKIP_CODE
| ClassReader.SKIP_DEBUG | ClassReader.SKIP_FRAMES);
return v.isFound();
}
private boolean found;
private final String targetDesc;
public HasAnnotation(ClassVisitor v, Class annotation) {
super(Opcodes.ASM5, v);
targetDesc = Type.getDescriptor(annotation);
}
public boolean isFound() {
return found;
}
@Override
public AnnotationVisitor visitAnnotation(String desc, boolean visible) {
if (targetDesc.equals(desc)) {
found = true;
}
return super.visitAnnotation(desc, visible);
}
}