code: public void setBaseDir(File baseDir) {
          if (this.baseDir != null && this.baseDir != baseDir && autoDelete) {
              rmDir(this.baseDir);
          }
          this.baseDir = baseDir;
      }
docs: Sets the base directory. If the new base directory is different from
  the current one and <code>autoDelete</code> is true, the current
  base directory's will be deleted. The new base directory need not exist
  yet. If it doesn't exist, it and all parent directories will be created
  the first time it's needed.
  
  @param baseDir the new value, never <code>null</code>.
  @throws NullPointerException if the value is null.