JavaAnnotations/src/main/java/AnnotationReflection.java at master · afinlay5/JavaAnnotations · GitHub

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Licensed under the MIT 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

https://opensource.org/licenses/MIT

Permission is hereby granted, free of charge, to any person obtaining a copy

of this software and associated documentation files (the "Software"), to deal

in the Software without restriction, including without limitation the rights

to use, copy, modify, merge, publish, distribute, sublicense, and/or sell

copies of the Software, and to permit persons to whom the Software is

furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all

copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR

IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,

FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE

AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER

LIABILITY, WHETHER INCLUDING AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,

OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE

SOFTWARE.

==============================================================================

**/

package src.main.java;

import java.lang.annotation.Annotation;

import java.lang.annotation.Retention;

import java.lang.annotation.Repeatable;

import java.lang.annotation.Target;

import java.lang.annotation.ElementType;

import java.lang.annotation.RetentionPolicy;

import java.lang.reflect.AnnotatedElement;

import java.lang.reflect.Field;

//Annotation #1 - SampleAnnotation.class

@Repeatable(SampleAnnotationContainer.class)

@Retention(RetentionPolicy.RUNTIME)

//Specify the various types we are tareting (Class, Method, Field, Constructor)

@Target({ElementType.TYPE, ElementType.METHOD, ElementType.FIELD, ElementType.CONSTRUCTOR})

@interface SampleAnnotation { String id(); }

//Container for Repeated instances of SampleAnnotation

@Retention(RetentionPolicy.RUNTIME)

@Target({ElementType.TYPE, ElementType.METHOD, ElementType.FIELD, ElementType.CONSTRUCTOR})

@interface SampleAnnotationContainer { SampleAnnotation[] value (); }

//Annotation #2 -

@Retention(RetentionPolicy.RUNTIME)

@interface SampleAnnotation2 { String id() default "Default ID #43216"; }

//#1 - Class Annotation

@SampleAnnotation(id = "Public Class #1834")

@SampleAnnotation(id = "Public Class #8124")

public class AnnotationReflection {

//#2 - Constructor Annotation

@SampleAnnotation(id = "Default Constructor #1834")

@SampleAnnotation(id = "Default Constructor #8124")

public AnnotationReflection () { }

//#3 - Field Annotation

@SampleAnnotation(id = "Field(String) #1834")

@SampleAnnotation(id = "Field(String) #8124")

public String cogic_friend = "Kerrie";

//#4 - Method Annotation

@SampleAnnotation2

@SampleAnnotation(id = "Main Method #1834")

@SampleAnnotation(id = "Main Method #8124")

public static void main(String[] args) {

//Object to use for reflection

AnnotationReflection an = new AnnotationReflection();

//Container for Anotations.

Annotation[] annos;

//(#1) Get Annotations on AnnotationReflection Class

annos = an.getClass().getAnnotations();

System.out.println("\nAnnotation #1 (Class):\t");

for (Annotation anno : annos) { System.out.println(anno + "\n"); }

//(#2) Get Annotations on AnnotationReflection() Constructor

try { annos = an.getClass().getConstructor().getAnnotations(); }

catch (NoSuchMethodException nme) { System.out.println("Exception thrown: " + nme + "\n"); return; }

System.out.println("Annotation #2 (Constructor): "); //The Constructor must be public.

for (Annotation anno : annos) { System.out.println(anno + "\n"); }

//(#3) Get Annotations on the AnnotationReflection.cogic_friend member

try { annos = an.getClass().getField("cogic_friend").getAnnotations(); }

catch (NoSuchFieldException | SecurityException e) { System.out.println("Exception thrown: " + e + "\n"); return; }

System.out.println("Annotation #3 (Field): ");

for (Annotation anno : annos) { System.out.println(anno + "\n"); }

//(#4) Get Annotations on the AnnotationReflection.main() method

try { annos = an.getClass().getMethod("main", String[].class).getAnnotations(); }

catch (NoSuchMethodException | SecurityException e) { System.out.println("Exception thrown: " + e + "\n"); return; }

System.out.println("Annotation #4 (Method): ");

for (Annotation anno : annos) { System.out.println(anno + "\n"); }

//Using an instance of the Annotation itself

SampleAnnotation2 sa2;

try { sa2 = an.getClass().getMethod("main", String[].class).getAnnotation(SampleAnnotation2.class);}

catch (NoSuchMethodException nme) { System.out.println(); return; }

System.out.println("\nAnnotation #4 (SampleAnnotation.class): \"" + sa2.id() + "\"\n");

}

JavaAnnotations/src/main/java/AnnotationReflection.java at master · afinlay5/JavaAnnotations · GitHub

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