David E. Wheeler > Params-CallbackRequest > Params::CallbackRequest::Exceptions

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Module Version: 1.20   Source  

NAME ^

Params::CallbackRequest::Exceptions - Parameter callback exception definitions

SYNOPSIS ^

  use Params::CallbackRequest::Exceptions;
  Params::Callback::Exception::Execution->throw("Whoops!");

  use Params::CallbackRequest::Exceptions abbr => [qw(throw_cb_exec)];
  throw_cb_exec "Whoops!";

DESCRIPTION ^

This module creates the exceptions used by Params::CallbackRequest and Params::Callback. The exceptions are subclasses of Exception::Class::Base, created by the interface defined by Exception::Class.

INTERFACE ^

Exported Functions

This module exports two functions by default.

isa_cb_exception

  eval { something_that_dies() };
  if (my $err = $@) {
      if (isa_cb_exception($err, 'Abort')) {
          print "All hands abandon ship!";
      } elsif (isa_cb_exception($err)) {
          print "I recall an exceptional fault.";
      } else {
          print "No clue.";
      }
  }

This function takes a single argument and returns true if it's a Params::Callback::Exception object. A second, optional argument can be used to identify a particular subclass of Params::Callback::Exception.

rethrow_exception

  eval { something_that_dies() };
  if (my $err = $@) {
      # Do something intelligent, and then...
      rethrow_exception($err);
  }

This function takes an exception as its sole argument and rethrows it. If the argument is an object that can('throw'), such as any subclass of Exception::Class, then rethrow_exception() will call its rethrow method. If not, but the argument is a reference, rethrow_exception() will simply die with it. And finally, if the argument is not a reference at all, rethrow_exception() will throw a new Params::Callback::Exception exception with the argument used as the exception error message.

Abbreviated Exception Functions

Each of the exception classes created by Params::CallbackRequest::Exceptions has a functional alias for its throw class method. These may be imported by passing an array reference of the names of the abbreviated functions to import via the abbr parameter:

  use Params::CallbackRequest::Exceptions abbr => [qw(throw_cb_exec)];

The names of the abbreviated functions are:

throw_cb

Params::Callback::Exception

throw_bad_key

Params::Callback::Exception::InvalidKey

throw_cb_exec

Params::Callback::Exception::Execution

throw_bad_params

Params::Callback::Exception::Params

throw_abort

Params::Callback::Exception::Abort

Exception Classes

The exception classes created by Params::Callback::Exception are as follows:

Params::Callback::Exception

This is the base class for all Params::Callback exception classes. Its functional alias is throw_cb.

Params::Callback::Exception::InvalidKey

Params::CallbackRequest throws this exception when a callback key in the parameter hash passed to new() has no corresponding callback. In addition to the attributes offered by Exception::Class::Base, this class also features the attribute callback_key. Use the callback_key() accessor to see what callback key triggered the exception. Params::Callback::Exception::InvalidKey's functional alias is throw_bad_key.

Params::Callback::Exception::Execution

This is the exception thrown by Params::CallbackRequest's default exception handler when a callback subroutine or method dies. In addition to the attributes offered by Exception::Class::Base, this class also features the attributes callback_key, which corresponds to the parameter key that triggered the callback, and callback_error which is the error thrown by the callback subroutine or method. Params::Callback::Exception::Execution's functional alias is throw_cb_exec.

Params::Callback::Exception::Params

This is the exception thrown when an invalid parameter is passed to Params::CallbackRequest's or Params::Callback's new() constructors. Its functional alias is throw_bad_params.

Params::Callback::Exception::Abort

This is the exception thrown by Params::Callback's abort() method. functional alias is throw_cb. In addition to the attributes offered by Exception::Class::Base, this class also features the attribute aborted_value attribute. Use the aborted_value() accessor to see what value was passed to abort(). Params::Callback::Exception::Abort's functional alias is throw_abort.

SEE ALSO ^

Params::Callback is the base class for all callback classes.

Params::CallbackRequest sets up callbacks for execution.

Exception::Class defines the interface for the exception classes created here.

SUPPORT ^

This module is stored in an open GitHub repository. Feel free to fork and contribute!

Please file bug reports via GitHub Issues or by sending mail to bug-params-callbackrequest@rt.cpan.org.

AUTHOR ^

David E. Wheeler <david@justatheory.com>

COPYRIGHT AND LICENSE ^

Copyright 2003-2011 David E. Wheeler. Some Rights Reserved.

This library is free software; you can redistribute it and/or modify it under the same terms as Perl itself.

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