Should I use delegation here?

Question

I currently have two class hierarchies: one for handling errors and another for logging them. I am wondering 1) whether it is advantageous to delegate error handling to a class separate from the error handler and 2) whether what I have is a good design.

Here is what I have:

class ErrorHandler {
  public __construct(ErrorLogger $ErrorLogger) {
    ...
    $this->setErrorPageURL('/error.php');
  }

  public function setErrorPageURL($errorPageURL);

  public function handle() {
    ...
    $this->ErrorLogger->log($errorNumber, $errorMessage, $errorFile, $errorLine);
    header("Location: $this->errorPageURL");
  }
}

class ErrorLogger {
  abstract protected function log($errorNumber, $errorMessage, $errorFile, $errorLine);

  // Overridable.
  protected function getExtraLogMessage() {
    return null;
  }
}

class EmailerErrorLogger extends ErrorLogger {
  public function __construct($toEmailAddress, $fromEmailAddress) {
    ...
  }

  protected function log($errorNumber, $errorMessage, $errorFile, $errorLine) {
    // collect error information and various pieces of information
    mail(...);
  }
}

register_shutdown_function(array(new ErrorHandler(new EmailerErrorLogger()), 'handle'));

Answer 1

I think this structure makes sense, because your error handler has to do certain other jobs than just logging the error.

The loggers themselves could implement the chain of responsibility pattern