* @return HashMap containing the chunks stored in the named directoryChunk
* @throws DirectoryChunkNotFoundException This is thrown should the directoryMap HashMap on this object be null
* or for some reason the directory is not found, is equal to null, or is for some reason not a HashMap/aka Directory Node.
*/
public HashMap getDirectoryChunk(String directoryName) throws DirectoryChunkNotFoundException {
DirectoryChunkNotFoundException excep = new DirectoryChunkNotFoundException(directoryName);
Object obj = getChunk(this.directoryMap, directoryName);
if(obj == null || !(obj instanceof HashMap)) throw excep;
return (HashMap)obj;
}