code: public List<String> getAllPDBIDs() throws IOException{
  
  		File f = new File(path);
  		if ( ! f.isDirectory())
  			throw new IOException("Path " + path + " is not a directory!");
  
  		String[] dirName = f.list();
  
  		List<String>pdbIds = new ArrayList<String>();
  		for (String dir : dirName) {
  			File d2= new File(f,dir);
  			if ( ! d2.isDirectory())
  				continue;
  
  			String[] pdbDirs = d2.list();
  			for (String pdbId : pdbDirs) {
  				if ( ! pdbIds.contains(pdbId))
  					pdbIds.add(pdbId);
  
  			}
  		}
  
  		return pdbIds;
  	}
docs: Returns a list of all PDB IDs that are available in this installation
  
  @return a list of PDB IDs