1Workflow::Factory(3) User Contributed Perl Documentation Workflow::Factory(3)
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6 Workflow::Factory - Generates new workflow and supporting objects
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9 This documentation describes version 1.18 of this package
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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 )
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 Returns: Workflow::Action object
183 get_persister( $persister_name )
185 Retrieves the persister with name $persister_name.
187 Throws exception if no persister with name $persister_name available.
189 get_condition( $condition_name )
191 Retrieves the condition with name $condition_name.
193 Throws exception if no condition with name $condition_name available.
195 get_validator( $validator_name )
197 Retrieves the validator with name $validator_name.
199 Throws exception if no validator with name $validator_name available.
201 Internal Configuration Methods
203 _add_workflow_config( @config_hashrefs )
204 Adds all configurations in @config_hashrefs to the factory. Also cycles
206 through the workflow states and creates a Workflow::State object for
207 each. These states are passed to the workflow when it is instantiated.
208 We also require any necessary observer classes and throw an exception
210 if we cannot. If successful the observers are kept around and attached
211 to a workflow in "create_workflow()" and "fetch_workflow()".
212 Returns: nothing
214 _add_action_config( @config_hashrefs )
216 Adds all configurations in @config_hashrefs to the factory, doing a
218 'require' on the class referenced in the 'class' attribute of each
219 action.
220 Throws an exception if there is no 'class' associated with an action or
222 if we cannot 'require' that class.
223 Returns: nothing
225 _add_persister_config( @config_hashrefs )
227 Adds all configurations in @config_hashrefs to the factory, doing a
229 'require' on the class referenced in the 'class' attribute of each
230 persister.
231 Throws an exception if there is no 'class' associated with a persister,
233 if we cannot 'require' that class, or if we cannot instantiate an
234 object of that class.
235 Returns: nothing
237 _add_condition_config( @config_hashrefs )
239 Adds all configurations in @config_hashrefs to the factory, doing a
241 'require' on the class referenced in the 'class' attribute of each
242 condition.
243 Throws an exception if there is no 'class' associated with a condition,
245 if we cannot 'require' that class, or if we cannot instantiate an
246 object of that class.
247 Returns: nothing
249 _add_validator_config( @config_hashrefs )
251 Adds all configurations in @config_hashrefs to the factory, doing a
253 'require' on the class referenced in the 'class' attribute of each
254 validator.
255 Throws an exception if there is no 'class' associated with a validator,
257 if we cannot 'require' that class, or if we cannot instantiate an
258 object of that class.
259 Returns: nothing
261 _commit_transaction
263 Calls the commit method in the workflow's persister.
265 Returns: nothing
267 _rollback_transaction
269 Calls the rollback method in the workflow's persister.
271 associate_observers_with_workflow
273 Add defined observers with workflow.
275 The workflow has to be provided as the single parameter accepted by
277 this method.
278 The observers added will have to be of the type relevant to the
280 workflow type.
281 new
283 The new method is a dummy constructor, since we are using a factory it
285 makes no sense to call new - and calling new will result in a
286 Workflow::Exception
287 "instance" should be called or the imported 'FACTORY' should be
289 utilized.
290
292 If you have either a large set of config files or a set of very large
293 config files then you may not want to incur the overhead of loading
294 each and every one on startup if you cannot predict which set you will
295 use in that instance of your application.
296 This approach doesn't make much sense in a persistent environment such
298 as mod_perl but it may lower startup costs if you have regularly
299 scheduled scripts that may not need to touch all possible types of
300 workflow.
301 To do this you can specify a callback that the factory will use to
303 retrieve batched hashes of config declarations. Whenever an unknown
304 workflow name is encountered the factory will first try to load your
305 config declarations then continue.
306 The callback takes one argument which is the workflow type. It should
308 return a reference to a hash of arguments in a form suitable for
309 "add_config_from_file".
310 For example:
312 use Workflow::Factory qw(FACTORY);
314 use My::Config::System;
315 sub init {
317 my $self = shift;
318 FACTORY->config_callback(
320 sub {
321 my $wf_type = shift;
322 my %ret = My::Config::System->get_files_for_wf( $wf_type ) || ();
323 return \%ret;
324 }
325 );
326 }
327
329 Implementation and Usage
330 You can subclass the factory to implement your own methods and still
331 use the useful facade of the "FACTORY" constant. For instance, the
332 implementation is typical Perl subclassing:
333 package My::Cool::Factory;
335 use strict;
337 use base qw( Workflow::Factory );
338 sub some_cool_method {
340 my ( $self ) = @_;
341 ...
342 }
343 To use your factory you can just do the typical import:
345 #!/usr/bin/perl
347 use strict;
349 use My::Cool::Factory qw( FACTORY );
350 Or you can call "instance()" directly:
352 #!/usr/bin/perl
354 use strict;
356 use My::Cool::Factory;
357 my $factory = My::Cool::Factory->instance();
359
361 Setting package variable $VALIDATE_ACTION_CONFIG to a true value (it is
362 undef by default) turns on optional validation of extra attributes of
363 Workflow::Action configs. See Workflow::Action for details.
364
366 Workflow
367 Workflow::Action
369 Workflow::Condition
371 Workflow::Config
373 Workflow::Persister
375 Workflow::Validator
377
379 Copyright (c) 2003-2010 Chris Winters. All rights reserved.
380 This library is free software; you can redistribute it and/or modify it
382 under the same terms as Perl itself.
383
385 Jonas B. Nielsen (jonasbn) <jonasbn@cpan.org> is the current
386 maintainer.
387 Chris Winters E <lt> chris @cwinters . comE <gt>, original author .
389perl v5.30.1 2020-01-30 Workflow::Factory(3)