SpringRestClientScannerConfigurer.java

package com.github.bingoohuang.springrestclient.spring;

import lombok.val;
import org.springframework.beans.BeansException;
import org.springframework.beans.PropertyValue;
import org.springframework.beans.PropertyValues;
import org.springframework.beans.factory.BeanNameAware;
import org.springframework.beans.factory.InitializingBean;
import org.springframework.beans.factory.config.ConfigurableListableBeanFactory;
import org.springframework.beans.factory.config.PropertyResourceConfigurer;
import org.springframework.beans.factory.config.TypedStringValue;
import org.springframework.beans.factory.support.BeanDefinitionRegistry;
import org.springframework.beans.factory.support.BeanDefinitionRegistryPostProcessor;
import org.springframework.beans.factory.support.BeanNameGenerator;
import org.springframework.beans.factory.support.DefaultListableBeanFactory;
import org.springframework.context.ApplicationContext;
import org.springframework.context.ApplicationContextAware;
import org.springframework.context.ConfigurableApplicationContext;
import org.springframework.context.support.GenericApplicationContext;
import org.springframework.util.StringUtils;

import static org.springframework.util.Assert.notNull;

public class SpringRestClientScannerConfigurer implements BeanDefinitionRegistryPostProcessor, InitializingBean, ApplicationContextAware, BeanNameAware {

    private String basePackage;

    private ApplicationContext applicationContext;

    private String beanName;

    private boolean processPropertyPlaceHolders;

    private BeanNameGenerator nameGenerator;

    /*
     * This property lets you set the base package for your mapper interface files.
     * <p/>
     * You can set more than one package by using a semicolon or comma as a separator.
     * <p/>
     * Mappers will be searched for recursively starting in the specified package(s).
     *
     * @param basePackage base package name
     */
    public void setBasePackage(String basePackage) {
        this.basePackage = basePackage;
    }

    public void setProcessPropertyPlaceHolders(boolean processPropertyPlaceHolders) {
        this.processPropertyPlaceHolders = processPropertyPlaceHolders;
    }

    /**
     * {@inheritDoc}
     */
    public void setApplicationContext(ApplicationContext applicationContext) {
        this.applicationContext = applicationContext;
    }

    /**
     * {@inheritDoc}
     */
    public void setBeanName(String name) {
        this.beanName = name;
    }

    /**
     * Gets beanNameGenerator to be used while running the scanner.
     *
     * @return the beanNameGenerator BeanNameGenerator that has been configured
     */
    public BeanNameGenerator getNameGenerator() {
        return nameGenerator;
    }

    /**
     * Sets beanNameGenerator to be used while running the scanner.
     *
     * @param nameGenerator the beanNameGenerator to set
     */
    public void setNameGenerator(BeanNameGenerator nameGenerator) {
        this.nameGenerator = nameGenerator;
    }

    /**
     * {@inheritDoc}
     */
    public void afterPropertiesSet() throws Exception {
        notNull(this.basePackage, "Property 'basePackage' is required");
    }

    /**
     * {@inheritDoc}
     */
    public void postProcessBeanFactory(ConfigurableListableBeanFactory beanFactory) {
        // left intentionally blank
    }

    /**
     * {@inheritDoc}
     */
    public void postProcessBeanDefinitionRegistry(BeanDefinitionRegistry registry) throws BeansException {
        if (this.processPropertyPlaceHolders) {
            processPropertyPlaceHolders();
        }

        ClassPathSpringRestClientScanner scanner = new ClassPathSpringRestClientScanner(registry);
        scanner.setResourceLoader(this.applicationContext);
        scanner.setBeanNameGenerator(this.nameGenerator);
        scanner.registerFilters();
        scanner.scan(StringUtils.tokenizeToStringArray(this.basePackage, ConfigurableApplicationContext.CONFIG_LOCATION_DELIMITERS));
    }

    /*
     * BeanDefinitionRegistries are called early in application startup, before
     * BeanFactoryPostProcessors. This means that PropertyResourceConfigurers will not have been
     * loaded and any property substitution of this class' properties will fail. To avoid this, find
     * any PropertyResourceConfigurers defined in the context and run them on this class' bean
     * definition. Then update the values.
     */
    private void processPropertyPlaceHolders() {
        val prcs = applicationContext.getBeansOfType(PropertyResourceConfigurer.class);

        if (!prcs.isEmpty() && applicationContext instanceof GenericApplicationContext) {
            val mapperScannerBean = ((GenericApplicationContext) applicationContext)
                .getBeanFactory().getBeanDefinition(beanName);

            // PropertyResourceConfigurer does not expose any methods to explicitly perform
            // property placeholder substitution. Instead, create a BeanFactory that just
            // contains this mapper scanner and post process the factory.
            val factory = new DefaultListableBeanFactory();
            factory.registerBeanDefinition(beanName, mapperScannerBean);

            for (PropertyResourceConfigurer prc : prcs.values()) {
                prc.postProcessBeanFactory(factory);
            }

            val values = mapperScannerBean.getPropertyValues();

            this.basePackage = updatePropertyValue("basePackage", values);
        }
    }

    private String updatePropertyValue(String propertyName, PropertyValues values) {
        PropertyValue property = values.getPropertyValue(propertyName);

        if (property == null) {
            return null;
        }

        Object value = property.getValue();

        if (value == null) {
            return null;
        } else if (value instanceof String) {
            return value.toString();
        } else if (value instanceof TypedStringValue) {
            return ((TypedStringValue) value).getValue();
        } else {
            return null;
        }
    }

}