/**
 * Jeff Rupp
 * Master's Thesis
 * 2005
 *
 * This is a utility class for discovering all the classes in a given
 *  classpath resource which are instances of a given type, or if the
 *  suffix of a file matches a given suffix.
 */


package jdr.utils;

import java.io.*;
import java.util.*;
import java.util.zip.*;

public class ClassPathHelper
{
    private static final String filesep = System.getProperty("file.separator");
    private static final String[] classPath = getClassPath();

    public static final FileFilter classFilter = new FileFilter()
    {
        public boolean accept(File file)
        {
            return file.getName().endsWith(".class");
        }
    };


    /** Return the system class path as an array of strings. */
    public static String[] getClassPath()
    {
        String classPath = System.getProperty("java.class.path");
        return getClassPath(classPath);
    }


    /** Convert a class path to an array of strings. A class path is
          a list of path names separated by the character in the
          <code>path.separator</code> system property.
     */
    public static String[] getClassPath(String path)
    {
        String pathsep = System.getProperty("path.separator");
        StringTokenizer tok = new StringTokenizer(path,pathsep);
        String[] s = new String[tok.countTokens()];
        for(int i = 0; tok.hasMoreTokens(); ++i)
            s[i] = tok.nextToken();
        return s;
    }

    public static ArrayList getClassesOfType(String path, String pkg, Class cl) throws Exception
    {
        ArrayList result = new ArrayList();

        // If the path is a zip or jar file, look inside for the
        // file
        String lPath = path.toLowerCase();

        ArrayList files = null;

        files = getFiles(path, classFilter);

        for(Iterator it = files.iterator();it.hasNext();)
        {
            String className = "";
            String res = "";
            if(lPath.endsWith(".zip") || lPath.endsWith(".jar"))
            {
                ZipEntry ze = (ZipEntry)it.next();
                className = ze.getName();
                res = className.replace('/', '.');
            }
            else
            {
                className = it.next().toString();
                res = className.replace(File.separatorChar, '.');
            }
            //System.out.println("classname: "+className);
            //System.out.println("resconv: "+res);
            int pkgIndex = res.indexOf(pkg);
            int clsIndex = res.lastIndexOf(".class");
            //System.out.println(pkg+" Index: "+pkgIndex+"  .class Index: "+clsIndex);
            if((pkgIndex >= 0) && (clsIndex > pkgIndex))
            {
                res = res.substring(pkgIndex, clsIndex);
                //System.out.println("res: "+res);
                try
                {
                    Class c = Class.forName(res);

                    if(cl.isAssignableFrom(c))
                    {
                        result.add(c.getName());
                    }
                    c = null;
                }
                catch(NoClassDefFoundError err)
                {
                    //System.out.println("Got err: " + err.getMessage());
                }
                catch(Exception ex)
                {
                    //System.out.println("Got: " + ex.getMessage());
                }
            }
        }
        return result;
    }


    public static ArrayList getFiles(String path, FileFilter filter)
    {
        String lPath = path.toLowerCase();
        if(lPath.endsWith(".zip") ||
           lPath.endsWith(".jar"))
        {

            try
            {
                return getFilesInJar(path,filter);
            }
            catch(Exception ex)
            {
                return new ArrayList();
            }
        }
        else
        {
            // Not a zip or jar file. Look for the resources in
            // a file/dir
            return getFilesInDir(path,filter);
        }

    }


    public static ArrayList getFilesInDir(String path, FileFilter filter)
    {
        ArrayList result = new ArrayList();
        File f = new File(path);
        if(f.exists())
        {
            if(f.isDirectory())
            {
                String[] files = f.list();
                for(int i = 0;i < files.length;i++)
                {
                    result.addAll(getFilesInDir(f.getAbsolutePath()+File.separator+files[i], filter));
                }
            }
            else
            {
                if(filter.accept(f))
                {
                    result.add(f);
                }
            }
        }
        return result;
    }


    /** Given a resource name and jar file name, open the jar file
      * and return a buffer containing the contents. Returns null
      * if the jar file could not be found or the resource could
      * not be found
      */
    public static ArrayList getFilesInJar(String jarFile, FileFilter filter) throws Exception
    {
        ArrayList result = new ArrayList();
        ZipFile zip = null;
        File f = new File(jarFile);

        // Make sure the file exists before opening it
        if(f.exists() &&
           f.isFile())
        {

            // Open the zip file
            zip = new ZipFile(f);
        }
        if(zip == null) return result;

        for(Enumeration en = zip.entries();en.hasMoreElements();)
        {
            ZipEntry ze = (ZipEntry)en.nextElement();
            if(filter.accept(new File(ze.getName())))
            {
                result.add(ze);
            }
        }
        return result;
    }

}