Workflow::Condition::Nested - Evaluate nested workflow conditions


This documentation describes version 1.61 of this package


Typically, the workflow conditions are evaluated directly by the framework in Workflow::State when the action is evaluated. This module allows a workflow condition to contain nested conditions that are evaluated directly rather than via separate workflow actions.

This allows the workflow to be designed to group multiple conditions and perform advanced operations like an OR comparision of multiple conditions with "greedy" evaluation (as opposed to "lazy" evaluation).

A usage example might be a case where 3 of 5 possible approvals are needed for an action to be allowed. The "Greedy OR" condition would define the list of conditions to be evaluated. After checking each condition, it would return the total number of successes. The result is then checked against the number needed, returning the boolean value needed by Workflow::State.

Note: This class is not used directly, but subclassed by your class that implements the evaluate() method and calls the evaluate_condition method to evaluate its nested conditions.


In condition.xml:

    <condition name="cond1" ... />
    <condition name="cond2" ... />
    <condition name="cond3" ... />
    <condition name="cond4" ... />
    <condition name="cond5" ... />

    <condition name="count_approvals" class="Workflow::Condition::GreedyOR">
        <param name="condition" value="cond1" />
        <param name="condition" value="cond2" />
        <param name="condition" value="cond3" />
        <param name="condition" value="cond4" />
        <param name="condition" value="cond5" />

    <condition name="check_approvals" class="Workflow::Condition::CheckReturn">
        <param name="condition" value="count_approvals" />
        <!-- operator "ge" means: greater than or equal to -->
        <param name="operator"  value="ge" />
        <param name="argument"  value="$context->{approvals_needed}" />

In workflow.xml:

    <state name="CHECK_APPROVALS" autorun="yes">
        <action name="null_1" resulting_state="APPROVED">
            <condition name="check_approvals" />
        <action name="null_2" resulting_state="REJECTED">
            <condition name="!check_approvals" />


See Workflow


Copyright (c) 2004-2022 Chris Winters. All rights reserved.

This library is free software; you can redistribute it and/or modify it under the same terms as Perl itself.

Please see the LICENSE


Please see Workflow