Params::CallbackRequest::Exceptions - Parameter callback exception definitions use Params::CallbackRequest::Exceptions; Params::Callback::Exception::Execution->throw("Whoops!"); use Params::CallbackRequest::Exceptions abbr => [qw(throw_cb_exec)]; throw_cb_exec "Whoops!"; 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.

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: Params::Callback::Exception Params::Callback::Exception::InvalidKey Params::Callback::Exception::Execution Params::Callback::Exception::Params 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". 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. David Wheeler <david@kineticode.com> Copyright 2003 by David Wheeler This library is free software; you can redistribute it and/or modify it under the same terms as Perl itself.