Thymeleaf TemplateEngine component

Thymeleaf TemplateEngine component

import java.io.IOException;
import java.io.InputStream;

import org.springframework.context.ApplicationContext;
import org.springframework.context.annotation.Bean;
import org.springframework.core.io.Resource;
import org.springframework.stereotype.Component;
import org.thymeleaf.TemplateEngine;
import org.thymeleaf.TemplateProcessingParameters;
import org.thymeleaf.resourceresolver.IResourceResolver;
import org.thymeleaf.templateresolver.TemplateResolver;
import org.thymeleaf.util.Validate;

import lombok.extern.slf4j.Slf4j;

@Component
public @Slf4j class CoreConfig {

	
	@Bean
	public TemplateEngine getThymeleafTemplateEngind(ApplicationContext context){
		
		
		// thymeleaf-spring4 dependency 설정 시 , viewResolver에 영향
		// IResourceResolver만 SpringResourceResolver참고하여 생성
		IResourceResolver resourceResolver = new IResourceResolver() {

			@Override
			public InputStream getResourceAsStream(
					TemplateProcessingParameters templateProcessingParameters,
					String resourceName) {
				Validate.notNull(resourceName, "Resource name cannot be null");
		        Validate.notNull(context,
		                "ApplicationContext has not been initialized in resource resolver. TemplateResolver or " +
		                "ResourceResolver might not have been correctly configured by the Spring Application Context.");

		        try {

		            final Resource resource = context.getResource(resourceName);
		            if (resource == null) {
		                return null;
		            }
		            return resource.getInputStream();
		        } catch (final IOException e) {
		            if (log.isDebugEnabled()) {
		                if (log.isTraceEnabled()) {
		                	log.trace(
		                            String.format(
		                                    "[THYMELEAF][%s][%s] Resource \"%s\" could not be resolved. This can be normal as " +
		                                            "maybe this resource is not intended to be resolved by this resolver. " +
		                                            "Exception is provided for tracing purposes: ",
		                                    TemplateEngine.threadIndex(), templateProcessingParameters.getTemplateName(),
		                                    resourceName),
		                            e);
		                } else {
		                	log.debug(
		                            String.format(
		                                    "[THYMELEAF][%s][%s] Resource \"%s\" could not be resolved. This can be normal as " +
		                                            "maybe this resource is not intended to be resolved by this resolver. " +
		                                            "Exception message is provided: %s: %s",
		                                    TemplateEngine.threadIndex(), templateProcessingParameters.getTemplateName(),
		                                    resourceName, e.getClass().getName(), e.getMessage()));
		                }
		            }
		            return null;
		        }
			}
			
			@Override
			public String getName() {
				// TODO Auto-generated method stub
				return "CoreConfig IResourceResolver Impl";
			}
		};
		
		
		TemplateResolver templateResolver = new TemplateResolver();
		templateResolver.setResourceResolver(resourceResolver);
		templateResolver.setCharacterEncoding("UTF-8");
		templateResolver.setPrefix("classpath:/templates/");
		templateResolver.setSuffix(".html");
		
		TemplateEngine engine = new TemplateEngine();
		engine.setTemplateResolver(templateResolver);

		return engine;
		
	}
}