Java Class Find getClasses(String pkgname, boolean flat)

Description

Scans all classes accessible from the context class loader which belong to the given package and subpackages.

License

Open Source License

Parameter

Parameter	Description
packageName	The base package
flat	scan only one package level, do not dive into subdirectories

Exception

Parameter	Description
ClassNotFoundException	an exception
IOException	an exception

Return

The classes

Declaration

protected static Class<?>[] getClasses(String pkgname, boolean flat) 

Method Source Code

//package com.java2s;
//License from project: Open Source License 

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

public class Main {
    /**/*from ww w . ja va 2 s  .  c o  m*/
     * Scans all classes accessible from the context class loader which belong
     * to the given package and subpackages.
     * 
     * @param packageName The base package
     * @param flat scan only one package level, do not dive into subdirectories
     * @return The classes
     * @throws ClassNotFoundException
     * @throws IOException
     */
    protected static Class<?>[] getClasses(String pkgname, boolean flat) {

        List<File> dirs = new ArrayList<File>();
        List<Class<?>> classes = new ArrayList<Class<?>>();

        ClassLoader classLoader = Thread.currentThread().getContextClassLoader();
        String path = pkgname.replace('.', '/');

        Enumeration<URL> resources = null;
        try {
            resources = classLoader.getResources(path);
        } catch (IOException e) {
            throw new RuntimeException("Cannot read path " + path, e);
        }

        while (resources.hasMoreElements()) {
            URL resource = resources.nextElement();
            dirs.add(new File(resource.getFile()));
        }

        for (File directory : dirs) {
            try {
                classes.addAll(findClasses(directory, pkgname, flat));
            } catch (ClassNotFoundException e) {
                throw new RuntimeException("Class not found", e);
            }
        }

        return classes.toArray(new Class<?>[classes.size()]);
    }

    /**
     * Recursive method used to find all classes in a given directory and
     * subdirectories.
     * 
     * @param dir base directory
     * @param pkgname package name for classes found inside the base directory
     * @param flat scan only one package level, do not dive into subdirectories
     * @return Classes list
     * @throws ClassNotFoundException
     */
    private static List<Class<?>> findClasses(File dir, String pkgname, boolean flat)
            throws ClassNotFoundException {

        List<Class<?>> classes = new ArrayList<Class<?>>();
        if (!dir.exists()) {
            return classes;
        }

        File[] files = dir.listFiles();
        for (File file : files) {
            if (file.isDirectory() && !flat) {
                classes.addAll(findClasses(file, pkgname + "." + file.getName(), flat));
            } else if (file.getName().endsWith(".class")) {
                classes.add(
                        Class.forName(pkgname + '.' + file.getName().substring(0, file.getName().length() - 6)));
            }
        }

        return classes;
    }
}

Related

1. getClasses(ClassLoader cl, String pack)
2. getClasses(final String packageName)
3. getClasses(final String packageName, final Class annotation)
4. getClasses(final String pckgname)
5. getClasses(String pack)
6. getClassesAsList(String pckgname, Class type)
7. getClassesDir(Class classWithinDir)
8. getClassesExtending(Class rootClass, String pattern)
9. getClassesInDirectory(File directory, String packageName, ClassLoader classLoader)