com.github.tddts.jet.config.spring.postprocessor.MessageAnnotationBeanPostProcessor.java Source code

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Here is the source code for com.github.tddts.jet.config.spring.postprocessor.MessageAnnotationBeanPostProcessor.java

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/*
 * Copyright 2018 Tigran Dadaiants
 *
 * Licensed under the Apache 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
 *
 * http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package com.github.tddts.jet.config.spring.postprocessor;

import com.github.tddts.jet.config.spring.annotations.Message;
import com.github.tddts.jet.util.SpringUtil;
import org.apache.commons.lang3.tuple.Pair;
import org.apache.logging.log4j.LogManager;
import org.apache.logging.log4j.Logger;
import org.springframework.beans.BeansException;
import org.springframework.beans.factory.BeanInitializationException;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.beans.factory.config.BeanPostProcessor;
import org.springframework.context.MessageSource;
import org.springframework.context.NoSuchMessageException;

import java.lang.reflect.AccessibleObject;
import java.lang.reflect.Field;
import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Method;
import java.util.Locale;

/**
 * {@code MessageAnnotationBeanPostProcessor} is a {@link BeanPostProcessor} that inserts messages to fields and methods
 * of processed beans which are marked by {@link Message} annotation.
 *
 * @author Tigran_Dadaiants dtkcommon@gmail.com
 */
public class MessageAnnotationBeanPostProcessor implements BeanPostProcessor {

    private static final Object[] EMPTY_ARGS = new Object[] {};

    private final Logger logger = LogManager.getLogger(MessageAnnotationBeanPostProcessor.class);

    @Autowired
    private MessageSource messageSource;

    @Override
    public Object postProcessBeforeInitialization(Object bean, String beanName) throws BeansException {

        Pair<Class<?>, Object> typeObjectPair = SpringUtil.checkForDinamicProxy(bean);
        Class<?> type = typeObjectPair.getLeft();
        Object target = typeObjectPair.getRight();

        Method[] methods = type.getDeclaredMethods();
        Field[] fields = type.getDeclaredFields();

        for (Method method : methods) {
            if (checkMethod(method, type))
                processMethod(target, method);
        }

        for (Field field : fields) {
            if (checkField(field, type))
                processField(target, field);
        }

        return bean;
    }

    private boolean checkMethod(Method method, Class<?> type) {
        if (!method.isAnnotationPresent(Message.class)) {
            return false;
        }
        if (method.getParameterCount() == 1 && method.getParameterTypes()[0].equals(String.class)) {
            return true;
        }
        logger.warn("Method [" + type + "." + method.getName()
                + "] is not populated with message. Method should have a single String parameter.");
        return false;
    }

    private boolean checkField(Field field, Class<?> type) {
        if (!field.isAnnotationPresent(Message.class)) {
            return false;
        }
        if (field.getType().equals(String.class)) {
            return true;
        }
        logger.warn("Field [" + type + "." + field.getName()
                + "] is not populated with message. Should be a String field.");
        return false;
    }

    private String preprocess(AccessibleObject accessibleObject) throws NoSuchMessageException {
        Message messageAnnotation = accessibleObject.getAnnotation(Message.class);
        String messageKey = messageAnnotation.value();
        String message = messageSource.getMessage(messageKey, EMPTY_ARGS, Locale.getDefault());
        accessibleObject.setAccessible(true);
        return message;
    }

    private void processMethod(Object bean, Method method) {
        try {
            String message = preprocess(method);
            method.invoke(bean, message);
        } catch (IllegalAccessException | InvocationTargetException e) {
            throw new BeanInitializationException(
                    "Injection of message failed for method [" + bean.getClass() + "." + method.getName() + "]", e);
        } catch (NoSuchMessageException e) {
            throw new BeanInitializationException(
                    "Failed to find message for method [" + bean.getClass() + "." + method.getName() + "]", e);
        }
    }

    private void processField(Object bean, Field field) {
        try {
            String message = preprocess(field);
            field.set(bean, message);
        } catch (IllegalAccessException e) {
            throw new BeanInitializationException(
                    "Injection of message failed for field [" + bean.getClass() + "." + field.getName() + "]", e);
        } catch (NoSuchMessageException e) {
            throw new BeanInitializationException(
                    "Failed to find message for field [" + bean.getClass() + "." + field.getName() + "]", e);
        }
    }

    @Override
    public Object postProcessAfterInitialization(Object bean, String beanName) throws BeansException {
        return bean;
    }
}