Class: OpenWFE::CursorCommandExpression

Inherits:

FlowExpression

• Object
• ObjectWithMeta
• FlowExpression
• OpenWFE::CursorCommandExpression

Includes:

CommandConstants, ConditionMixin

Defined in:

lib/openwfe/expressions/fe_command.rb

Overview

This class implements the following expressions : back, break, cancel, continue, jump, rewind, skip.

They are generally used inside of a ‘cursor’ (CursorExpression) or a ‘loop’ (LoopExpression), they can be used outside, but their result (the value of the field ‘_cursor_command_’ will be used as soon as the flow enters a cursor or a loop).

In fact, this expression is only a nice wrapper that sets the value of the field “_cursor_command_” to its name (‘back’ for example) plus to the ‘step’ attribute value.

For example <skip step=“3”/> simply sets the value of the field ‘_cursor_command_’ to ‘skip 3’.

(The field _cursor_command_ is, by default, read and obeyed by the ‘cursor’ expression).

With Ruby process definitions, you can directly write :

skip 2
jump "0"

instead of

skip :step => "2"
jump :step => "0"

Likewise, in an XML process definition, you can write

<skip>2</skip>

although that might still look lighter (it’s longer though) :

<skip step="2"/>

About the command themselves :

• back : will go back from the number of given steps, 1 by default

• break : will exit the cursor (or the loop)

• cancel : an alias for ‘break’

• continue : will exit the cursor, if in a loop, will get back at step 0

• jump : will move the cursor (or loop) to an absolute given position (count starts at 0)

• rewind : an alias for continue

• skip : skips the given number of steps

All those command support an ‘if’ attribute to restrict their execution :

cursor do
    go_to_shop
    check_prices
    _break :if => "${price} > ${f:current_cash}"
    buy_stuff
end

The ‘rif’ attribute may be used instead of the ‘if’ attribute. Its value is some ruby code that, when evaluating to true will let the command be executed.

_skip 2, :rif => "workitem.customers.size % 2 == 0"
    #
    # skips if the nb of customers is pair

Note that the ‘rif’ attribute will work only if the :ruby_eval_allowed parameter is set to true in the engine’s application context.

engine.application_context[:ruby_eval_allowed] = true

Instance Attribute Summary

Attributes inherited from FlowExpression

#apply_time, #attributes, #children, #environment_id, #fei, #parent_id, #raw_representation

Attributes included from Contextual

#application_context

Instance Method Summary

• #apply(workitem) ⇒ Object

Methods included from ConditionMixin

#determine_condition_attribute, #eval_condition

Methods inherited from FlowExpression

#cancel, #clean_children, #delete_variable, #dup_environment, #fetch_environment, #fetch_text_content, #get_binding, #get_environment, #get_parent, #get_root_environment, #has_attribute, #initialize, is_definition, is_definition?, #lookup_attribute, #lookup_attributes, #lookup_boolean_attribute, #lookup_comma_list_attribute, #lookup_downcase_attribute, #lookup_ref, #lookup_string_attribute, #lookup_sym_attribute, #lookup_value, #lookup_variable, #lookup_vf_attribute, names, #new_environment, new_exp, #owns_its_environment?, #paused?, #remove_child, #reply, #reply_to_parent, #set_variable, #store_itself, #synchronize, #to_s, #to_yaml_properties

Methods included from Contextual

#get_work_directory, #init_service, #lookup

Methods included from Logging

#ldebug, #ldebug_callstack, #lerror, #lfatal, #linfo, #llog, #lunknown, #lwarn

Methods included from OwfeServiceLocator

#get_engine, #get_error_journal, #get_expool, #get_expression_map, #get_expression_pool, #get_expression_storage, #get_expression_storages, #get_journal, #get_participant_map, #get_scheduler, #get_wfid_generator

Methods inherited from ObjectWithMeta

#class_def, meta_def, meta_eval, metaclass

Constructor Details

This class inherits a constructor from OpenWFE::FlowExpression

Instance Method Details

#apply(workitem) ⇒ Object

# File 'lib/openwfe/expressions/fe_command.rb', line 216

def apply (workitem)

    conditional = eval_condition(:if, workitem, :unless)
        #
        # for example : <break if="${approved} == true"/>

    if conditional == nil or conditional

        command = @fei.expression_name

        step = lookup_attribute(A_STEP, workitem)
        step = fetch_text_content(workitem) unless step
        step = 1 unless step
        step = Integer(step)

        command = "#{command} #{step}" #if step != 1

        workitem.attributes[F_COMMAND] = command
    end

    reply_to_parent workitem
end