POE-Component-Basement

NAME

POE::Component::Basement

SYNOPSIS

package POE::MyComponent;

      #  use as base
      use base qw/ POE::Component::Basement /;
  
      #  where the initializations happen (see Class::Std)
      sub BUILD { ... }
  
      #  see also Class::Std and Class::Data::Inheritable also 
      #  for accessor creation etc.
  
      #  define states
      sub state_one   : State( :inline<start> ) { ... }
      sub statetwo   : State( :object<foo> ) { ... }
      sub state_three : State( :package<bar> ) { ... }
  
      #  combined
      sub state_multi : State( :inline<foobar> :package<snafoo> ) { ... }
      ...

      #  chained events
      sub first : State( :object<foo> :chained<bar> ) { ... }
      sub second : State( :object<bar> ) { ... }
      ...

      #  calling in a row
      sub first : State( :object<foo> :next<bar> ) { ... }
      sub second : State( :object<bar> ) { ... }
      ...
  
      #  usage
      my $comp = POE::MyComponent->new ({
  
          #  single alias or array reference for multiple
          aliases => [qw/ mycomp shub_niggurath /],

          ...  #  your specific init_arg's.
      });

DESCRIPTION

Provides Class::Std and base POE component functionality. This module is still kinda experimental.

CLASS AND INSTANCE DATA
Setting "session_class"
Determines on which class the session should be built on. To use, for instance, POE::Session::MessageBased, set the option like this:

MyComponent->session_class( 'POE::Session::MessageBased' );

The default is POE::Session.

Option "aliases"
Can be a single value to be set as alias, or an array reference. If the latter, POE::Kernel's "alias_set" is called for each of it's elements. This must be supplied as argument to the "new" method. See SYNOPSIS for examples.

ATTRIBUTES

This module just uses the attribute "State" and delegates all other attribute handling to Class::Std. Parameters can multiple, separated by spaces. They look like those of Class::Std to be coherent. As an

example

sub start_event : State( :inline<_start> ) {

... }

This would create an "inline_state" for our session, named "_start".

inline, package and object
Create "inline_states", "package_states" or "object_states" in your session. Multiple specifications of these parameters cause multiple events to be defined. Have a look at POE for more information.

chained

      sub first : State( :inline<start> :chained<end> ) { 
          print "Called first.\n";
          return 23;
      }
  
      sub end : State( :inline<end> ) {
          my $lastreturn = $[ARG0];
          print "Called second. First returned $lastreturn\n";
      }

Specifies with which event the current state should be chained. If you use "chained", the given event will be triggered after the sub has completed. It's return values will be passed to the chained event.

      #  the event gets triggered
      POE::Kernel->yield( foo => 333 );

      sub first : State( :inline<foo> :next<bar> ) {
          my ( $nr ) = $_[ARG0];
          ...
      }
  
      sub second : State( :inline<bar> ) {
          my ( $nr ) = $_[ARG0];
          ...
      }

An event that was specified with "next" is triggered right after completion of the current subroutine. The "next" event gets the same parameters as the current.

error

      sub first : State( :inline<foo> :error<error_occured> ) {
          die "in the name of Cthulhu";
      }

      sub second : State( :inline<error_occured> ) {
          my $error = $_[ARG0];
          print 'An Error has occured: ' . $error;
      }

If an "error" handling state is defined, "PCB" will build an "eval" block around the subroutine call and emit the event specified with "error". First argument is the error message.

INHERITANCE

Currently, you can overload the called methods in package and object states. Though you have to do this without specifying a new "State()" attribute. The new method has the same attributes as the overriden. The latter can also be called with NEXT. This basic way works like:

      #  the original
      package Original;
      sub whatever : State( :package<_start> ) { ... }
      ...
  
      #  the new one
      package NewOne;
      use base qw/ Original /;
      sub whatever { ... }

But for information, I'm planning the possibility to override specific events.

METHODS

Methods starting with an underline ("_") is thought as internal to POE::Component::Basement and should therefore not be called directly.

parseattributes

( $name, $param ) = parseattribute( $attribute )

Takes an attribute and tries to split it into name and parameters. Returns undef if nothing usable found.

new
Constructor. See SYNOPSIS for usage. This overrides the "new" method provided by Class::Std.

MODIFY_CODE_ATTRIBUTES
This is an internal sub that's responsible for building your state-map, as it is called on specification of an attribute. See perldoc's attributes for more information about this subject. This is an internal function, do not call directly.

createmodified_state

$code = createmodified_state( \&coderef, \%params );

Does the wrapping for the more enhanced attributes. Internal, do not call.

register_states

void register_states( $class, $coderef, { state_name => 'type' } );

Registers states corresponding to a specific code reference. Accepted state names are "inline", "package" and "object". Internal, do not call.

flatteninheritance

@classes_in_family = flatteninheritance( $rootclass )

Returns an array with names of classes used in the specified $rootclass' inheritance tree. This is internal, do not call.

get_states

\%struct = $comp->get_states()

Returns a structure containing the defined inline, package and object states ready to use for POE::Sessions constructor. Internal and restricted, do not call.

getsymbol_name

$subname = getsymbol_name( $class, $coderef );

Searches for a code reference in the symbol table of a class and returns the sub's name if found. Otherwise undef. Do not call.

parseparameters

%parameters = parseparameters( $parameter_string )

This function looks for parameters formed like :name<value> and returns them in ( name => value, .. ) like pairs. Dies on malformed or unknown parameters. Internal method, do not call.

SEE ALSO

POE, Class::Std, Class::Data::Inheritable

REQUIRES

POE, Class::Std, Carp, Scalar::Util, NEXT, Sub::Installer, Class::Data::Inheritable

AUTHOR

Robert Sedlacek <phaylon@dunkelheit.at>

LICENSE

You can copy and/or modify this module under the same terms as perl itself.