Attempts to list all the classes in the specified package as determined by the context class loader... : ClassLoader « Reflection « Java

1. Java
2. Reflection
3. ClassLoader

Attempts to list all the classes in the specified package as determined by the context class loader...

        


import java.io.ByteArrayOutputStream;
import java.io.File;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.io.UnsupportedEncodingException;
import java.net.URL;
import java.net.URLDecoder;
import java.security.CodeSource;
import java.security.ProtectionDomain;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.Enumeration;
import java.util.HashMap;
import java.util.List;
import java.util.jar.JarEntry;
import java.util.jar.JarFile;

public class FileUtils {
  
  static int BUFFER_SIZE = 10*1024;
  
  /**
     * Attempts to list all the classes in the specified package as determined
     * by the context class loader...
     * 
     * @param pckgname
     *            the package name to search
     * @return a list of classes that exist within that package
     * @throws ClassNotFoundException
     *             if something went wrong
     */
    public static List<Class<?>> getClassesInSamePackage(Class<?>... classes) throws ClassNotFoundException {
      ArrayList<Class<?>> result = new ArrayList<Class<?>>();
      if(classes == null || classes.length == 0) 
        return result;
        // 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        
      ArrayList<File> directories = new ArrayList<File>();
        HashMap<File,String> packageNames = null; 
        String pckgname = null;
        try {          
            ClassLoader cld = Thread.currentThread().getContextClassLoader();
            if (cld == null) {
                throw new ClassNotFoundException("Can't get class loader.");
            }
            for(Class<?> clazz: classes) {
              // TODO: this would not work in a non OSGi environment
              String syspath = getBundlePath(clazz);
              if(syspath.endsWith("/")) {
                syspath = syspath.substring(0, syspath.length()-1);
              } else if(syspath.endsWith(".jar")) {
                getClassesInSamePackageFromJar(result, classes, syspath);
                continue;
              }
              pckgname = clazz.getPackage().getName();
              String path = pckgname.replace('.', '/');
              // Ask for all resources for the path
              Enumeration<URL> resources = cld.getResources(path);
              File directory = null;
              while (resources.hasMoreElements()) {
                String path2 = resources.nextElement().getPath();                
                if (!path2.contains(syspath)) {
                  // needed to get it working on Eclipse 3.5
                  if(syspath.indexOf("/bin")<1) {
                    syspath = syspath + "/bin";
                  }
                    directory = new File(URLDecoder.decode(syspath+path2, "UTF-8"));
                } else
                  directory = new File(URLDecoder.decode(path2, "UTF-8"));
                directories.add(directory);
              }
              if (packageNames == null)
                packageNames = new HashMap<File, String>();
              packageNames.put(directory,pckgname);
            }
        } catch (NullPointerException x) {
            throw new ClassNotFoundException(pckgname + " does not appear to be a valid package (Null pointer exception)");
        } catch (UnsupportedEncodingException encex) {
            throw new ClassNotFoundException(pckgname + " 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 " + pckgname);
        }
         
        // 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
                String[] files = directory.list();
                for (String file : files) {
                  System.out.println(file);
                    // we are only interested in .class files
                    if (file.endsWith(".class")) {
                      try {
                        // removes the .class extension
                        result.add(Class.forName(packageNames.get(directory) + '.' + file.substring(0, file.length() - 6)));
                      } catch (Throwable e) {
                        // ignore exception and continue 
                      }
                    }
                }
            } else {
                throw new ClassNotFoundException(pckgname + " (" + directory.getPath() + ") does not appear to be a valid package");
            }
        }
        return result;
    }
    

    /**
     * Returns the list of classes in the same directories as Classes in <code>classes</code>.
     * 
     * @param result
     * @param classes
     * @param jarPath
     */
    private static void getClassesInSamePackageFromJar(List<Class<?>> result, Class<?>[] classes, String jarPath) {
      JarFile jarFile = null;      
      try {
        jarFile = new JarFile(jarPath);
        //ClassLoader cld = Thread.currentThread().getContextClassLoader();
        Enumeration<JarEntry> en = jarFile.entries();
        while(en.hasMoreElements()) {
          JarEntry entry = en.nextElement();
          String entryName = entry.getName();        
          for(Class<?> clazz: classes) {            
            String packageName = clazz.getPackage().getName().replace('.', '/');                              
            if(entryName != null && entryName.endsWith(".class") && entryName.startsWith(packageName)) {              
              try {
                Class<?> entryClass = Class.forName(entryName.substring(0,entryName.length()-6).replace('/', '.'));
                if(entryClass != null)
                  result.add(entryClass);          
              } catch (Throwable e) {
              // do nothing, just continue processing classes
            }
            }
          }          
        }
      } catch (Exception e) {
        result.addAll(Arrays.asList(classes));
      } finally {
        try {
          if(jarFile != null)
            jarFile.close();
        } catch (Exception e) {      
      }
      }
    }
    
    /**
     * Returns the location of the 
     * 
     * @param clazz
     * @return
     */
    public static String getBundlePath(Class<?> clazz) {
      ProtectionDomain pd = clazz.getProtectionDomain();
    if (pd == null)
      return null;
    CodeSource cs = pd.getCodeSource();
    if (cs == null)
      return null;
    URL url = cs.getLocation();
    if (url == null)
      return null;
    String result = url.getFile();
    return result;
    }  
}

   
    
    
    
    
    
    
    
  

Related examples in the same category