returns the annotation of clazz if present otherwise returns null - Java java.lang.annotation

Java examples for java.lang.annotation:Annotation Attribute

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Description

returns the annotation of clazz if present otherwise returns null

Demo Code


//package com.java2s;
import java.lang.annotation.Annotation;

public class Main {
    public static void main(String[] argv) throws Exception {
        Class clazz = String.class;
        String key = "java2s.com";
        System.out.println(getAnnotationValueForClass(clazz, key));
    }/*w w  w .jav  a2 s  . co  m*/

    private static String getAnnotationValueForClass(Class clazz, String key) {
        String s = "";
        Annotation[] annotations = clazz.getAnnotations();
        for (Annotation a : annotations) {
            s = getValueFromAnntotationToString(key, a.toString());
            if (s != null && !s.isEmpty()) {
                break;
            }
        }
        return s;
    }

    /**
     * returns the annotation of clazz if present otherwise returns null
     * 
     * @param clazz
     * @param classAnnotation
     * @return
     */
    public static Annotation getAnnotationValueForClass(Class clazz,
            Class classAnnotation) {
        Annotation a = clazz.getAnnotation(classAnnotation);
        return a;
    }

    /**
     * used for annotation Processing to return a value Annotation(key=value)
     * 
     * @param value
     *            this is the key used to find a value in the string
     * @param annotaionString
     *            this is the .toString() method used for the annotation
     * @return
     */
    private static String getValueFromAnntotationToString(String value,
            String annotaionString) {
        String string = "";
        string = annotaionString.substring(
                annotaionString.indexOf("(") + 1,
                annotaionString.indexOf(")"));
        String[] strings = string.split(",");
        if (strings != null && strings.length > 0) {
            for (String s : strings) {
                if (s.contains(value)) {
                    string = s.split("=")[1];
                }
            }
        }
        return string;
    }
}

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