Main.java Source code

Introduction

Here is the source code for Main.java

Source

//package com.java2s;
import java.io.File;
import java.io.IOException;
import java.io.UnsupportedEncodingException;

import java.net.JarURLConnection;
import java.net.URL;
import java.net.URLDecoder;
import java.util.ArrayList;

import java.util.Collections;
import java.util.Enumeration;
import java.util.List;

import java.util.jar.JarEntry;
import java.util.jar.JarFile;

public class Main {
    private static final String CLASS_EXTENSION = ".class";

    public static List<Class<?>> getClassesForPackage(final String iPackageName, final ClassLoader iClassLoader)
            throws ClassNotFoundException {
        // This will hold a list of directories matching the pckgname.
        // There may be more than one if a package is split over multiple jars/paths
        List<Class<?>> classes = new ArrayList<Class<?>>();
        ArrayList<File> directories = new ArrayList<File>();
        try {
            // Ask for all resources for the path
            final String packageUrl = iPackageName.replace('.', '/');
            Enumeration<URL> resources = iClassLoader.getResources(packageUrl);
            if (!resources.hasMoreElements()) {
                resources = iClassLoader.getResources(packageUrl + CLASS_EXTENSION);
                if (resources.hasMoreElements()) {
                    throw new IllegalArgumentException(
                            iPackageName + " does not appear to be a valid package but a class");
                }
            } else {
                while (resources.hasMoreElements()) {
                    URL res = resources.nextElement();
                    if (res.getProtocol().equalsIgnoreCase("jar")) {
                        JarURLConnection conn = (JarURLConnection) res.openConnection();
                        JarFile jar = conn.getJarFile();
                        for (JarEntry e : Collections.list(jar.entries())) {

                            if (e.getName().startsWith(iPackageName.replace('.', '/'))
                                    && e.getName().endsWith(CLASS_EXTENSION) && !e.getName().contains("$")) {
                                String className = e.getName().replace("/", ".").substring(0,
                                        e.getName().length() - 6);
                                classes.add(Class.forName(className));
                            }
                        }
                    } else
                        directories.add(new File(URLDecoder.decode(res.getPath(), "UTF-8")));
                }
            }
        } catch (NullPointerException x) {
            throw new ClassNotFoundException(
                    iPackageName + " does not appear to be " + "a valid package (Null pointer exception)");
        } catch (UnsupportedEncodingException encex) {
            throw new ClassNotFoundException(
                    iPackageName + " does not appear to be " + "a valid package (Unsupported encoding)");
        } catch (IOException ioex) {
            throw new ClassNotFoundException(
                    "IOException was thrown when trying " + "to get all resources for " + iPackageName);
        }

        // For every directory identified capture all the .class files
        for (File directory : directories) {
            if (directory.exists()) {
                // Get the list of the files contained in the package
                File[] files = directory.listFiles();
                for (File file : files) {
                    if (file.isDirectory()) {
                        classes.addAll(findClasses(file, iPackageName));
                    } else {
                        String className;
                        if (file.getName().endsWith(CLASS_EXTENSION)) {
                            className = file.getName().substring(0,
                                    file.getName().length() - CLASS_EXTENSION.length());
                            classes.add(Class.forName(iPackageName + '.' + className));
                        }
                    }
                }
            } else {
                throw new ClassNotFoundException(
                        iPackageName + " (" + directory.getPath() + ") does not appear to be a valid package");
            }
        }
        return classes;
    }

    /**
     * Recursive method used to find all classes in a given directory and subdirs.
     * 
     * @param iDirectory
     *          The base directory
     * @param iPackageName
     *          The package name for classes found inside the base directory
     * @return The classes
     * @throws ClassNotFoundException
     */
    private static List<Class<?>> findClasses(final File iDirectory, String iPackageName)
            throws ClassNotFoundException {
        final List<Class<?>> classes = new ArrayList<Class<?>>();
        if (!iDirectory.exists())
            return classes;

        iPackageName += "." + iDirectory.getName();

        String className;
        final File[] files = iDirectory.listFiles();
        for (File file : files) {
            if (file.isDirectory()) {
                if (file.getName().contains("."))
                    continue;
                classes.addAll(findClasses(file, iPackageName));
            } else if (file.getName().endsWith(CLASS_EXTENSION)) {
                className = file.getName().substring(0, file.getName().length() - CLASS_EXTENSION.length());
                classes.add(Class.forName(iPackageName + '.' + className));
            }
        }
        return classes;
    }
}