get annotations by given fields and methods - Java java.lang.annotation

Java examples for java.lang.annotation:Field Annotation

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Description

get annotations by given fields and methods

Demo Code


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

public class Main {
    /**/*from  w  ww .j  a v a2s . c  o  m*/
     * get annotations by given fields and methods
     * 
     * @param fields
     * @param methods
     * @return
     */
    public static Annotation[] getAnnotations(Set<Field> fields,
            Set<Method> methods) {
        List<Annotation> annotations = new LinkedList<Annotation>();
        if (fields != null) {
            for (Field field : fields) {
                Annotation[] annos = field.getAnnotations();
                if (annos != null) {
                    for (Annotation annotation : annos) {
                        annotations.add(annotation);
                    }
                }
            }
        }
        if (methods != null) {
            for (Method method : methods) {
                Annotation[] annos = method.getAnnotations();
                if (annos != null) {
                    for (Annotation annotation : annos) {
                        annotations.add(annotation);
                    }
                }
            }
        }
        return annotations.toArray(new Annotation[annotations.size()]);
    }

    /**
     * get annotations by given fields and methods, and filter by given
     * annotationClass. annotation need to equals or presented by given
     * annotation class.
     * 
     * @param fields
     * @param methods
     * @param annotationClass
     * @return
     */
    public static Annotation[] getAnnotations(Set<Field> fields,
            Set<Method> methods, Class<? extends Annotation> annotationClass) {
        return filterAnnotations(getAnnotations(fields, methods),
                annotationClass);
    }

    /**
     * filter annotations by given class. annotation need to equals or presented
     * by given annotation class.
     * 
     * @param annotations
     * @param annotationClass
     * @return
     */
    public static Annotation[] filterAnnotations(Annotation[] annotations,
            Class<? extends Annotation> annotationClass) {
        List<Annotation> list = new LinkedList<Annotation>();
        if (annotations != null) {
            for (Annotation annotation : annotations) {
                Class<?> annotationType = annotation.annotationType();
                if (annotationType == annotationClass) {
                    list.add(annotation);
                } else if (annotationType
                        .isAnnotationPresent(annotationClass)) {
                    list.add(annotation);
                }
            }
        }
        return list.toArray(new Annotation[list.size()]);
    }
}

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