Retrieving fields list of specified class and which are annotated by incoming annotation class If recursively is true, retrieving fields from all class hierarchy - Java Reflection

Java examples for Reflection:Field

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Description

Retrieving fields list of specified class and which are annotated by incoming annotation class If recursively is true, retrieving fields from all class hierarchy

Demo Code


//package com.java2s;
import java.lang.annotation.Annotation;
import java.lang.reflect.Field;
import java.util.Collections;
import java.util.LinkedList;
import java.util.List;

public class Main {
    public static void main(String[] argv) throws Exception {
        Class clazz = String.class;
        Class annotationClass = String.class;
        boolean recursively = true;
        System.out.println(java.util.Arrays
                .toString(getAnnotatedDeclaredFields(clazz,
                        annotationClass, recursively)));
    }//from  ww  w .  j av a2 s.  com

    /**
     * Retrieving fields list of specified class and which
     * are annotated by incoming annotation class
     * If recursively is true, retrieving fields from all class hierarchy
     *
     * @param clazz - where fields are searching
     * @param annotationClass - specified annotation class
     * @param recursively param
     * @return list of annotated fields
     */
    public static Field[] getAnnotatedDeclaredFields(Class clazz,
            Class<? extends Annotation> annotationClass, boolean recursively) {
        Field[] allFields = getDeclaredFields(clazz, recursively);
        List<Field> annotatedFields = new LinkedList<Field>();
        for (Field field : allFields) {
            if (field.isAnnotationPresent(annotationClass))
                annotatedFields.add(field);
        }

        return annotatedFields.toArray(new Field[annotatedFields.size()]);
    }

    /**
     * Retrieving fields list of specified class
     * If recursively is true, retrieving fields from all class hierarchy
     *
     * @param clazz where fields are searching
     * @param recursively param
     * @return list of fields
     */
    public static Field[] getDeclaredFields(Class clazz, boolean recursively) {
        List<Field> fields = new LinkedList<Field>();
        Field[] declaredFields = clazz.getDeclaredFields();
        Collections.addAll(fields, declaredFields);

        Class superClass = clazz.getSuperclass();

        if (superClass != null && recursively) {
            Field[] declaredFieldsOfSuper = getDeclaredFields(superClass,
                    recursively);
            if (declaredFieldsOfSuper.length > 0)
                Collections.addAll(fields, declaredFieldsOfSuper);
        }

        return fields.toArray(new Field[fields.size()]);
    }
}

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