get Class Names In Package - Java Reflection

Java examples for Reflection:package

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Description

get Class Names In Package

Demo Code

/* //  w w w .  j  a va2 s.c o m
 * ClassListHelper.java
 * Christoph Egger
 * $Revision$
 * 
 * Copyright (C) 2010 FTW (Telecommunications Research Center Vienna)
 * 
 *
 * This file is part of BIQINI, a free Policy and Charging Control Function
 * for session-based services.
 *
 * BIQINI is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version
 *
 * For a license to use the BIQINI software under conditions
 * other than those described here, or to purchase support for this
 * software, please contact FTW by e-mail at the following addresses:
 * fpcc@ftw.at ??
 *
 * BIQINI is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. ?See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License 
 * along with this program; if not, write to the Free Software 
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA ?02111-1307 ?USA
 */
//package com.java2s;
import java.io.File;

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

public class Main {
    public static void main(String[] argv) throws Exception {
        String _PackageName = "java2s.com";
        System.out.println(getClassNamesInPackage(_PackageName));
    }

    public static ArrayList<String> getClassNamesInPackage(
            String _PackageName) throws ClassNotFoundException {
        ArrayList<String> classes = new ArrayList<String>();
        // Get a File object for the package
        File directory = null;
        try {
            ClassLoader cld = Thread.currentThread()
                    .getContextClassLoader();
            if (cld == null) {
                throw new ClassNotFoundException("Can't get class loader.");
            }
            String path = _PackageName.replace('.', '/');
            URL resource = cld.getResource(path);
            if (resource == null) {
                throw new ClassNotFoundException("No resource for " + path);
            }
            directory = new File(resource.getFile());
        } catch (NullPointerException x) {
            throw new ClassNotFoundException(_PackageName + " ("
                    + directory + ") does not appear to be a valid package");
        }
        if (directory.exists()) {
            // Get the list of the files contained in the package
            String[] files = directory.list();
            for (int i = 0; i < files.length; i++) {
                // we are only interested in .class files
                if (files[i].endsWith(".class")) {
                    // removes the .class extension 
                    classes.add(_PackageName + '.'
                            + files[i].substring(0, files[i].length() - 6));
                }
            }
        } else {
            throw new ClassNotFoundException(_PackageName
                    + " does not appear to be a valid package");
        }

        return classes;
    }
}

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