ClassFromPackage.java

package com.malcom.library.android;


import java.io.File;
import java.io.IOException;
import java.net.URL;
import java.net.URLDecoder;
import java.util.ArrayList;
import java.util.Enumeration;
import java.util.List;

import android.util.Log;

/**
 * 
 * @author Malcom Ventures S.L
 * @since 2012
 *
 */
public class ClassFromPackage {
	
	/**
     * Scans all classes accessible from the context class loader which belong to the given package and subpackages.
     *
     * @param packageName The base package
     * @return The classes
     * @throws ClassNotFoundException
     * @throws IOException
     */
    @SuppressWarnings("unchecked") 
    public List<Class> getClasses(String packageName)
            throws ClassNotFoundException, IOException 
    {
    	
        ClassLoader classLoader = Thread.currentThread().getContextClassLoader();
        assert classLoader != null;
        String path = packageName.replace('.', '/');
        
        Log.d("ClassFromPackage", "________Fichero: "+path);
        
        Enumeration<URL> resources = classLoader.getResources(path);
        List<File> dirs = new ArrayList<File>();
        while (resources.hasMoreElements()) {
            URL resource = resources.nextElement();
            String fileName = resource.getFile();
            String fileNameDecoded = URLDecoder.decode(fileName, "UTF-8");
            dirs.add(new File(fileNameDecoded));
        }
        
        Log.d("ClassFromPackage", "________Directorios: "+dirs.size());
        
        ArrayList<Class> classes = new ArrayList<Class>();
        for (File directory : dirs) {
            classes.addAll(findClasses(directory, packageName));
        }
        return classes;
    }

    /**
     * Recursive method used to find all classes in a given directory and subdirs.
     *
     * @param directory   The base directory
     * @param packageName The package name for classes found inside the base directory
     * @return The classes
     * @throws ClassNotFoundException
     */
    @SuppressWarnings("unchecked")
	private List<Class> findClasses(File directory, String packageName) throws ClassNotFoundException 
	{
        List<Class> classes = new ArrayList<Class>();
        if (!directory.exists()) {
            return classes;
        }
        File[] files = directory.listFiles();
        for (File file : files) {
        	String fileName = file.getName();
            if (file.isDirectory()) {
                assert !fileName.contains(".");
            	classes.addAll(findClasses(file, packageName + "." + fileName));
            } else if (fileName.endsWith(".class") && !fileName.contains("$")) {
            	Class _class;
				try {
					_class = Class.forName(packageName + '.' + fileName.substring(0, fileName.length() - 6));
				} catch (ExceptionInInitializerError e) {
					// happen, for example, in classes, which depend on 
					// Spring to inject some beans, and which fail, 
					// if dependency is not fulfilled
					_class = Class.forName(packageName + '.' + fileName.substring(0, fileName.length() - 6),
							false, Thread.currentThread().getContextClassLoader());
				}
				classes.add(_class);
            }
        }
        return classes;
    }

}