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Merge branch '7.4' into 8.0
* 7.4: Minor tweak [Workflow] Add weighted transitions
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‎workflow.rst‎

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@@ -388,6 +388,233 @@ when needed and vice-versa when working with your objects::
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// ...
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};
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Using Weighted Transitions
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~~~~~~~~~~~~~~~~~~~~~~~~~~
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.. versionadded:: 7.4
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Support for weighted transitions was introduced in Symfony 7.4.
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A key feature of workflows (as opposed to state machines) is that an object can
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be in multiple places simultaneously. For example, when building a product, you
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might assemble several components in parallel. However, in the previous example,
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each place could only record whether the object was there or not, like a binary flag.
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**Weighted transitions** introduce multiplicity: a place can now track how many
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times an object is in that place. Technically, weighted transitions allow you to
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define transitions where multiple tokens (instances) are consumed from or produced
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to places. This is useful for modeling complex workflows such as manufacturing
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processes, resource allocation, or any scenario where multiple instances of something
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need to be produced or consumed.
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For example, imagine a table-making workflow where you need to create 4 legs, 1 top,
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and track the process with a stopwatch. You can use weighted transitions to model this:
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.. configuration-block::
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.. code-block:: yaml
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# config/packages/workflow.yaml
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framework:
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workflows:
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make_table:
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type: 'workflow'
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marking_store:
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type: 'method'
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property: 'marking'
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supports:
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- App\Entity\TableProject
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initial_marking: init
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places:
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- init
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- prepare_leg
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- prepare_top
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- stopwatch_running
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- leg_created
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- top_created
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- finished
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transitions:
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start:
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from: init
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to:
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- place: prepare_leg
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weight: 4
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- place: prepare_top
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weight: 1
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- place: stopwatch_running
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weight: 1
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build_leg:
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from: prepare_leg
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to: leg_created
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build_top:
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from: prepare_top
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to: top_created
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join:
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from:
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- place: leg_created
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weight: 4
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- top_created # weight defaults to 1
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- stopwatch_running
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to: finished
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.. code-block:: xml
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<!-- config/packages/workflow.xml -->
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<?xml version="1.0" encoding="UTF-8" ?>
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<container xmlns="http://symfony.com/schema/dic/services"
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xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
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xmlns:framework="http://symfony.com/schema/dic/symfony"
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xsi:schemaLocation="http://symfony.com/schema/dic/services
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https://symfony.com/schema/dic/services/services-1.0.xsd
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http://symfony.com/schema/dic/symfony
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https://symfony.com/schema/dic/symfony/symfony-1.0.xsd">
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<framework:config>
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<framework:workflow name="make_table" type="workflow">
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<framework:marking-store type="method">
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<framework:argument>marking</framework:argument>
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</framework:marking-store>
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<framework:support>App\Entity\TableProject</framework:support>
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<framework:initial-marking>init</framework:initial-marking>
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<framework:place>init</framework:place>
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<framework:place>prepare_leg</framework:place>
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<framework:place>prepare_top</framework:place>
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<framework:place>stopwatch_running</framework:place>
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<framework:place>leg_created</framework:place>
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<framework:place>top_created</framework:place>
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<framework:place>finished</framework:place>
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<framework:transition name="start">
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<framework:from>init</framework:from>
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<framework:to weight="4">prepare_leg</framework:to>
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<framework:to weight="1">prepare_top</framework:to>
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<framework:to weight="1">stopwatch_running</framework:to>
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</framework:transition>
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<framework:transition name="build_leg">
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<framework:from>prepare_leg</framework:from>
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<framework:to>leg_created</framework:to>
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</framework:transition>
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<framework:transition name="build_top">
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<framework:from>prepare_top</framework:from>
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<framework:to>top_created</framework:to>
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</framework:transition>
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<framework:transition name="join">
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<framework:from weight="4">leg_created</framework:from>
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<framework:from>top_created</framework:from>
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<framework:from>stopwatch_running</framework:from>
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<framework:to>finished</framework:to>
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</framework:transition>
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</framework:workflow>
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</framework:config>
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</container>
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.. code-block:: php
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// config/packages/workflow.php
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use App\Entity\TableProject;
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use Symfony\Config\FrameworkConfig;
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return static function (FrameworkConfig $framework): void {
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$makeTable = $framework->workflows()->workflows('make_table');
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$makeTable
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->type('workflow')
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->supports([TableProject::class])
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->initialMarking(['init']);
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$makeTable->markingStore()
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->type('method')
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->property('marking');
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$makeTable->place()->name('init');
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$makeTable->place()->name('prepare_leg');
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$makeTable->place()->name('prepare_top');
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$makeTable->place()->name('stopwatch_running');
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$makeTable->place()->name('leg_created');
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$makeTable->place()->name('top_created');
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$makeTable->place()->name('finished');
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$makeTable->transition()
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->name('start')
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->from(['init'])
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->to([
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['place' => 'prepare_leg', 'weight' => 4],
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['place' => 'prepare_top', 'weight' => 1],
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['place' => 'stopwatch_running', 'weight' => 1],
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]);
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$makeTable->transition()
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->name('build_leg')
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->from(['prepare_leg'])
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->to(['leg_created']);
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$makeTable->transition()
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->name('build_top')
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->from(['prepare_top'])
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->to(['top_created']);
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$makeTable->transition()
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->name('join')
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->from([
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['place' => 'leg_created', 'weight' => 4],
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'top_created', // weight defaults to 1
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'stopwatch_running',
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])
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->to(['finished']);
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};
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In this example, when the ``start`` transition is applied, it creates 4 tokens in
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the ``prepare_leg`` place, 1 token in ``prepare_top``, and 1 token in
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``stopwatch_running``. Then, the ``build_leg`` transition must be applied 4 times
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(once for each token), and the ``build_top`` transition once. Finally, the ``join``
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transition can only be applied when all 4 legs are created, the top is created,
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and the stopwatch is still running.
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Weighted transitions can also be defined programmatically using the
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:class:`Symfony\\Component\\Workflow\\Arc` class::
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use Symfony\Component\Workflow\Arc;
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use Symfony\Component\Workflow\Definition;
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use Symfony\Component\Workflow\Transition;
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use Symfony\Component\Workflow\Workflow;
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$definition = new Definition(
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['init', 'prepare_leg', 'prepare_top', 'stopwatch_running', 'leg_created', 'top_created', 'finished'],
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[
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new Transition('start', 'init', [
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new Arc('prepare_leg', 4),
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new Arc('prepare_top', 1),
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'stopwatch_running', // defaults to weight 1
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]),
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new Transition('build_leg', 'prepare_leg', 'leg_created'),
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new Transition('build_top', 'prepare_top', 'top_created'),
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new Transition('join', [
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new Arc('leg_created', 4),
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'top_created',
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'stopwatch_running',
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], 'finished'),
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]
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);
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$workflow = new Workflow($definition);
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$workflow->apply($subject, 'start');
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// Build each leg (4 times)
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$workflow->apply($subject, 'build_leg');
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$workflow->apply($subject, 'build_leg');
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$workflow->apply($subject, 'build_leg');
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$workflow->apply($subject, 'build_leg');
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// Build the top
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$workflow->apply($subject, 'build_top');
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// Now we can join all parts
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$workflow->apply($subject, 'join');
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The ``Arc`` class takes two parameters: the place name and the weight (which must be
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greater than or equal to 1). When a place is specified as a simple string instead of
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an ``Arc`` object, it defaults to a weight of 1.
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Using a multiple state marking store
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~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
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