BeanNamePlaceholderRegistryPostProcessor.java

package com.ulisesbocchio.jasyptspringboot.configuration;

import lombok.extern.slf4j.Slf4j;
import org.springframework.beans.BeansException;
import org.springframework.beans.factory.config.BeanDefinition;
import org.springframework.beans.factory.config.ConfigurableListableBeanFactory;
import org.springframework.beans.factory.support.BeanDefinitionRegistry;
import org.springframework.beans.factory.support.BeanDefinitionRegistryPostProcessor;
import org.springframework.beans.factory.support.DefaultListableBeanFactory;
import org.springframework.core.Ordered;
import org.springframework.core.env.Environment;

import java.util.stream.Stream;

/**
 * Bean Definition Registry Post Processor that looks for placeholders in bean names and resolves them, re-defining
 * those beans
 * with the new names.
 */
@Slf4j
class BeanNamePlaceholderRegistryPostProcessor implements BeanDefinitionRegistryPostProcessor, Ordered {

    private Environment environment;

    BeanNamePlaceholderRegistryPostProcessor(Environment environment) {
        this.environment = environment;
    }

    @Override
    public void postProcessBeanDefinitionRegistry(BeanDefinitionRegistry registry) throws BeansException {
        DefaultListableBeanFactory bf = (DefaultListableBeanFactory) registry;
        Stream.of(bf.getBeanDefinitionNames())
                //Look for beans with placeholders name format: '${placeholder}' or '${placeholder:defaultValue}'
                .filter(name -> name.matches("\\$\\{[\\w.-]+(?>:[\\w.-]+)?\\}"))
                .forEach(placeholder -> {
                    String actualName = environment.resolveRequiredPlaceholders(placeholder);
                    BeanDefinition bd = bf.getBeanDefinition(placeholder);
                    bf.removeBeanDefinition(placeholder);
                    bf.registerBeanDefinition(actualName, bd);
                    log.debug("Registering new name '{}' for Bean definition with placeholder name: {}", actualName, placeholder);
                });
    }

    @Override
    public void postProcessBeanFactory(ConfigurableListableBeanFactory beanFactory) throws BeansException {

    }

    @Override
    public int getOrder() {
        return Ordered.LOWEST_PRECEDENCE - 1;
    }
}