1Workflow::Factory(3) User Contributed Perl Documentation Workflow::Factory(3)
2
6 Workflow::Factory - Generates new workflow and supporting objects
7
9 This documentation describes version 1.59 of this package
10
12 # Import the singleton for easy access
13 use Workflow::Factory qw( FACTORY );
14 # Add XML configurations to the factory
16 FACTORY->add_config_from_file( workflow => 'workflow.xml',
17 action => [ 'myactions.xml', 'otheractions.xml' ],
18 validator => [ 'validator.xml', 'myvalidators.xml' ],
19 condition => 'condition.xml',
20 persister => 'persister.xml' );
21 # Create a new workflow of type 'MyWorkflow'
23 my $wf = FACTORY->create_workflow( 'MyWorkflow' );
24 # Fetch an existing workflow with ID '25'
26 my $wf = FACTORY->fetch_workflow( 'MyWorkflow', 25 );
27
29 Public
30 The Workflow Factory is your primary interface to the workflow system.
31 You give it the configuration files and/or data structures for the
32 Workflow, Workflow::Action, Workflow::Condition, Workflow::Persister,
33 and Workflow::Validator objects and then you ask it for new and
34 existing Workflow objects.
35 Internal
37 Developers using the workflow system should be familiar with how the
38 factory processes configurations and how it makes the various
39 components of the system are instantiated and stored in the factory.
40
42 Public Methods
43 instance()
44 The factory is a singleton, this is how you get access to the instance.
46 You can also just import the 'FACTORY' constant as in the "SYNOPSIS".
47 create_workflow( $workflow_type, $context, $wf_class )
49 Create a new workflow of type $workflow_type. This will create a new
51 record in whatever persistence mechanism you have associated with
52 $workflow_type and set the workflow to its initial state.
53 The $context argument is optional, you can pass an exisiting instance
55 of Workflow::Context to be reused. Otherwise a new instance is created.
56 The $wf_class argument is optional. Pass it the name of a class to be
58 used for the workflow to be created. By default, all workflows are of
59 the Workflow class.
60 Any observers you've associated with this workflow type will be
62 attached to the returned workflow object.
63 This fires a 'create' event from the just-created workflow object. See
65 "WORKFLOWS ARE OBSERVABLE" in Workflow for more.
66 Returns: newly created workflow object.
68 fetch_workflow( $workflow_type, $workflow_id, $context, $wf_class )
70 Retrieve a workflow object of type $workflow_type and ID $workflow_id.
72 (The $workflow_type is necessary so we can fetch the workflow using the
73 correct persister.) If a workflow with ID $workflow_id is not found
74 "undef" is returned.
75 The $context argument is optional, you can pass an exisiting instance
77 of Workflow::Context to be reused. Otherwise a new instance is created.
78 The $wf_class argument is optional. Pass it the name of a class to be
80 used for the workflow to be created. By default, all workflows are of
81 the Workflow class.
82 Any observers you've associated with this workflow type will be
84 attached to the returned workflow object.
85 This fires a 'fetch' event from the retrieved workflow object. See
87 "WORKFLOWS ARE OBSERVABLE" in Workflow for more.
88 Throws exception if no workflow type $workflow_type available.
90 Returns: Workflow object
92 add_config_from_file( %config_declarations )
94 Pass in filenames for the various components you wish to initialize
96 using the keys 'action', 'condition', 'persister', 'validator' and
97 'workflow'. The value for each can be a single filename or an arrayref
98 of filenames.
99 The system is familiar with the 'perl' and 'xml' configuration formats
101 -- see the 'doc/configuration.txt' for what we expect as the format and
102 will autodetect the types based on the file extension of each file.
103 Just give your file the right extension and it will be read in
104 properly.
105 You may also use your own custom configuration file format -- see
107 "SUBCLASSING" in Workflow::Config for what you need to do.
108 You can also read it in yourself and add the resulting hash reference
110 directly to the factory using "add_config()". However, you need to
111 ensure the configurations are added in the proper order -- when you add
112 an 'action' configuration and reference 'validator' objects, those
113 objects should already be read in. A good order is: 'validator',
114 'condition', 'action', 'workflow'. Then just pass the resulting hash
115 references to "add_config()" using the right type and the behavior
116 should be exactly the same.
117 Returns: nothing; if we run into a problem parsing one of the files or
119 creating the objects it requires we throw a Workflow::Exception.
120 add_config( %config_hashrefs )
122 Similar to "add_config_from_file()" -- the keys may be 'action',
124 'condition', 'persister', 'validator' and/or 'workflow'. But the values
125 are the actual configuration hashrefs instead of the files holding the
126 configurations.
127 You normally will only need to call this if you are programmatically
129 creating configurations (e.g., hot-deploying a validator class
130 specified by a user) or using a custom configuration format and for
131 some reason do not want to use the built-in mechanism in
132 Workflow::Config to read it for you.
133 Returns: nothing; if we encounter an error trying to create the objects
135 referenced in a configuration we throw a Workflow::Exception.
136 get_persister_for_workflow_type
138 get_persisters
140 #TODO
142 get_validators
144 #TODO
146 Internal Methods
148 #TODO
149 save_workflow( $workflow )
151 Stores the state and current datetime of the $workflow object. This is
153 normally called only from the Workflow "execute_action()" method.
154 This method respects transactions if the selected persister supports
156 it. Currently, the DBI-based persisters will commit the workflow
157 transaction if everything executes successfully and roll back if
158 something fails. Note that you need to manage any
159 Workflow::Persister::DBI::ExtraData transactions yourself.
160 Returns: $workflow
162 get_workflow_history( $workflow )
164 Retrieves all Workflow::History objects related to $workflow.
166 NOTE: Normal users get the history objects from the Workflow object
168 itself. Under the covers it calls this.
169 Returns: list of Workflow::History objects
171 get_action( $workflow, $action_name ) [ deprecated ]
173 Retrieves the action $action_name from workflow $workflow. Note that
175 this does not do any checking as to whether the action is proper given
176 the state of $workflow or anything like that. It is mostly an internal
177 method for Workflow (which does do checking as to the propriety of the
178 action) to instantiate new actions.
179 Throws exception if no action with name $action_name available.
181 get_action_config( $workflow, $action_name )
183 Retrieves the configuration for action $action_name as specified in the
185 actions configuration file, with the keys listed in the 'action'
186 section of Workflow::Config
187 Throws exception if no action with name $action_name available.
189 Returns: A hash with the configuration as its keys.
191 get_persister( $persister_name )
193 Retrieves the persister with name $persister_name.
195 Throws exception if no persister with name $persister_name available.
197 get_condition( $condition_name )
199 Retrieves the condition with name $condition_name.
201 Throws exception if no condition with name $condition_name available.
203 get_validator( $validator_name )
205 Retrieves the validator with name $validator_name.
207 Throws exception if no validator with name $validator_name available.
209 Internal Configuration Methods
211 _add_workflow_config( @config_hashrefs )
212 Adds all configurations in @config_hashrefs to the factory. Also cycles
214 through the workflow states and creates a Workflow::State object for
215 each. These states are passed to the workflow when it is instantiated.
216 We also require any necessary observer classes and throw an exception
218 if we cannot. If successful the observers are kept around and attached
219 to a workflow in create_workflow() and fetch_workflow().
220 Returns: nothing
222 _load_observers( $workflow_config_hashref )
224 Loads and adds observers based on workflow type
226 Returns number indicating amount of observers added, meaning zero can
228 indicate success based on expected outcome.
229 _add_action_config( @config_hashrefs )
231 Adds all configurations in @config_hashrefs to the factory, doing a
233 'require' on the class referenced in the 'class' attribute of each
234 action.
235 Throws an exception if there is no 'class' associated with an action or
237 if we cannot 'require' that class.
238 Returns: nothing
240 _add_persister_config( @config_hashrefs )
242 Adds all configurations in @config_hashrefs to the factory, doing a
244 'require' on the class referenced in the 'class' attribute of each
245 persister.
246 Throws an exception if there is no 'class' associated with a persister,
248 if we cannot 'require' that class, or if we cannot instantiate an
249 object of that class.
250 Returns: nothing
252 _add_condition_config( @config_hashrefs )
254 Adds all configurations in @config_hashrefs to the factory, doing a
256 'require' on the class referenced in the 'class' attribute of each
257 condition.
258 Throws an exception if there is no 'class' associated with a condition,
260 if we cannot 'require' that class, or if we cannot instantiate an
261 object of that class.
262 Returns: nothing
264 _add_validator_config( @config_hashrefs )
266 Adds all configurations in @config_hashrefs to the factory, doing a
268 'require' on the class referenced in the 'class' attribute of each
269 validator.
270 Throws an exception if there is no 'class' associated with a validator,
272 if we cannot 'require' that class, or if we cannot instantiate an
273 object of that class.
274 Returns: nothing
276 _commit_transaction
278 Calls the commit method in the workflow's persister.
280 Returns: nothing
282 _rollback_transaction
284 Calls the rollback method in the workflow's persister.
286 associate_observers_with_workflow
288 Add defined observers with workflow.
290 The workflow has to be provided as the single parameter accepted by
292 this method.
293 The observers added will have to be of the type relevant to the
295 workflow type.
296 new
298 The new method is a dummy constructor, since we are using a factory it
300 makes no sense to call new - and calling new will result in a
301 Workflow::Exception
302 "instance" should be called or the imported 'FACTORY' should be
304 utilized.
305
307 If you have either a large set of config files or a set of very large
308 config files then you may not want to incur the overhead of loading
309 each and every one on startup if you cannot predict which set you will
310 use in that instance of your application.
311 This approach doesn't make much sense in a persistent environment such
313 as mod_perl but it may lower startup costs if you have regularly
314 scheduled scripts that may not need to touch all possible types of
315 workflow.
316 To do this you can specify a callback that the factory will use to
318 retrieve batched hashes of config declarations. Whenever an unknown
319 workflow name is encountered the factory will first try to load your
320 config declarations then continue.
321 The callback takes one argument which is the workflow type. It should
323 return a reference to a hash of arguments in a form suitable for
324 "add_config_from_file".
325 For example:
327 use Workflow::Factory qw(FACTORY);
329 use My::Config::System;
330 sub init {
332 my $self = shift;
333 FACTORY->config_callback(
335 sub {
336 my $wf_type = shift;
337 my %ret = My::Config::System->get_files_for_wf( $wf_type ) || ();
338 return \%ret;
339 }
340 );
341 }
342
344 Implementation and Usage
345 You can subclass the factory to implement your own methods and still
346 use the useful facade of the "FACTORY" constant. For instance, the
347 implementation is typical Perl subclassing:
348 package My::Cool::Factory;
350 use strict;
352 use base qw( Workflow::Factory );
353 sub some_cool_method {
355 my ( $self ) = @_;
356 ...
357 }
358 To use your factory you can just do the typical import:
360 #!/usr/bin/perl
362 use strict;
364 use My::Cool::Factory qw( FACTORY );
365 Or you can call "instance()" directly:
367 #!/usr/bin/perl
369 use strict;
371 use My::Cool::Factory;
372 my $factory = My::Cool::Factory->instance();
374
376 Setting package variable $VALIDATE_ACTION_CONFIG to a true value (it is
377 undef by default) turns on optional validation of extra attributes of
378 Workflow::Action configs. See Workflow::Action for details.
379
381 • Workflow
382 • Workflow::Action
384 • Workflow::Condition
386 • Workflow::Config
388 • Workflow::Persister
390 • Workflow::Validator
392
394 Copyright (c) 2003-2022 Chris Winters. All rights reserved.
395 This library is free software; you can redistribute it and/or modify it
397 under the same terms as Perl itself.
398 Please see the LICENSE
400
402 Please see Workflow
403perl v5.34.0 2022-02-06 Workflow::Factory(3)