ClassUtils.java

package kr.co.inger.hotwind.utils;

import java.lang.annotation.Annotation;
import java.util.HashSet;
import java.util.List;
import java.util.Set;

import org.apache.commons.lang.ObjectUtils;
import org.reflections.Reflections;
import org.reflections.scanners.ResourcesScanner;
import org.reflections.scanners.SubTypesScanner;
import org.reflections.scanners.TypeAnnotationsScanner;
import org.reflections.util.ClasspathHelper;
import org.reflections.util.ConfigurationBuilder;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import com.google.common.base.Strings;

public class ClassUtils {

	private static Logger logger = LoggerFactory.getLogger(ClassUtils.class);

	/** 특정 패키지 이하의, 특정 어노테이션 지정된 클래스들 찾기. */
	public static Set<Class<?>> findAnnotatedClasses(final String rootPackage,
			final Class<? extends Annotation> klassAnnotation) {
		Reflections reflections = new Reflections(new ConfigurationBuilder()
				.addUrls(ClasspathHelper.forPackage(rootPackage)).setScanners(
						new ResourcesScanner(), new TypeAnnotationsScanner(),
						new SubTypesScanner()));
		Set<Class<?>> annotatedKlasses = reflections
				.getTypesAnnotatedWith(klassAnnotation);
		logger.info(ObjectUtils.toString(annotatedKlasses));
		return annotatedKlasses;
	}

	public static Set<Class<?>> findClassesByPackagesAndAnnotations(
			List<Object> packageNames, List<Object> annotationFqns) {
		//
		Set<Class<?>> result = new HashSet<Class<?>>();
		//
		for (Object packageNameObj : packageNames) {
			if (Strings.isNullOrEmpty((String) packageNameObj))
				continue;
			final String pakcageName = ObjectUtils.toString(packageNameObj);
			for (Object annotationFqnObj : annotationFqns) {
				final String annotationFqn = ObjectUtils
						.toString(annotationFqnObj);
				//
				Class<? extends Annotation> klassAnnotation = null;
				try {
					klassAnnotation = (Class<? extends Annotation>) Class
							.forName(annotationFqn);
				} catch (ClassNotFoundException e) {
					logger.warn(String.format("%s class-get fail! -- skip",
							annotationFqn), e);
				}
				if (klassAnnotation != null) {
					final Set<Class<?>> classes = findAnnotatedClasses(
							pakcageName, klassAnnotation);
					result.addAll(classes);
				}
			}
		}
		//
		return result;
	}

	/**
	 * 모든 Jersey 리소스 클래스들을 등록. 실제로 모듈로서 이들을 활용하지 않고(인스턴스로 만들지도 않음.), 단지 바인딩만 하여
	 * 이후 요청에 있어서 처리에만 활용한다.
	 * 
	 * @param classFqns
	 */
	public static Set<Class<?>> findClassesByFqns(final List<Object> classFqns) {
		Set<Class<?>> result = new HashSet<Class<?>>();
		for (final Object classFqn : classFqns) {
			try {
				Class klass = (Class) Class.forName((String) classFqn);
				result.add(klass);
			} catch (Exception exc) {
				logger.warn(String.format("find-class fail, skip -- fqn=[%s]",
						classFqn), exc);
			}
		}
		return result;
	}
}