sclass FilesBasedStringMap extends AbstractMap<S> {
  File dir;
  
  *() {}
  *(File *dir) {}
  
  public S get(O a) {
    
  }
  
  public synchronized Set<Map.Entry<S,S>> entrySet() {
    
  }
  
  public put(S a, S b) {
  }
  
  public S remove(O a) {
  }
}