check Candidate class for annotation - Java java.lang.annotation

Java examples for java.lang.annotation:Class Annotation

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Description

check Candidate class for annotation

Demo Code


//package com.java2s;

import java.lang.annotation.Annotation;
import java.lang.annotation.ElementType;
import java.lang.annotation.Target;
import java.lang.reflect.Constructor;
import java.lang.reflect.Field;
import java.lang.reflect.Method;

public class Main {
    public static void main(String[] argv) throws Exception {
        String className = "java2s.com";
        Class searchedAnnotation = String.class;
        System.out.println(checkCandidate(className, searchedAnnotation));
    }//from w w  w. j  av  a  2  s  .c o m

    public static <T extends Annotation> Class<?> checkCandidate(
            String className, Class<T> searchedAnnotation) {
        try {
            Class<?> candidateClass = Class.forName(className);
            Target target = searchedAnnotation.getAnnotation(Target.class);
            for (ElementType elementType : target.value()) {
                switch (elementType) {
                case TYPE:
                    if (candidateClass.getAnnotation(searchedAnnotation) != null)
                        return candidateClass;
                    break;
                case CONSTRUCTOR:
                    for (Constructor<?> constructor : candidateClass
                            .getConstructors())
                        if (constructor.getAnnotation(searchedAnnotation) != null)
                            return candidateClass;
                    break;
                case METHOD:
                    for (Method method : candidateClass.getMethods())
                        if (method.getAnnotation(searchedAnnotation) != null)
                            return candidateClass;
                    break;
                case FIELD:
                    for (Field field : candidateClass.getFields())
                        if (field.getAnnotation(searchedAnnotation) != null)
                            return candidateClass;
                    break;
                default:
                    break;
                }
            }
        } catch (ClassNotFoundException e) {
        } catch (NoClassDefFoundError e) {
        }
        return null;
    }
}

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