SEKE 2012 Proceedings - Knowledge Systems Institute

concrete language syntax; and behavior can be a mapping or
transformation into another language [6,7].
III. ACTION DESCRIPTION LANGUAGE
Fig. 2 illustrates the ADL metamodel considered as th e
source model that corresponds to the target model or the
activity diagram metamodel presented in Fig. 1. Meta Object
Facility [8] is used to develop ADL on the basis of the objects
or tokens residing the activity diagram. Rather than focusing on
actions that do not enable the detection of objects between two
actions, this research opts to focus on objects as th e key
concept to link between two actions. In other words, an action
is regarded as the relation of two objects. Therefore, an action
must have at least one input object and one output object.
Figure 2. ADL metamodel
Since the intent of ADL is to explain relations between
objects, or actions, the textual notation language is developed
in terms of actions and relations of actions. The language
contains the keywords:
action, end, decision, if, then, else, endif,
initiate, break, terminate
And the textual syntax grammar built on EBNF [9] is defined
as following:
::= 'diagram' ( |
| )* 'end'
::= 'action'
* 'end'
::= 'name'
| '' (','
)*
| 'precondition'
| 'postcondition'
::= '->'
['[' ']'] ('->'
['[' ']'])*
::= 'decision' 'from'
* 'end'
::= 'if' 'then'
()* ('else'
()*)* 'endif'
::= |
::= (','
)*
A. Defining Input and Output of An Action
Since the approach uses an object to create a co nnection
between two actions, the grammar of a n action is defined as
follows:
action a
O2 /* an output object O2 */
end
Hence, an action can be described as a path in directed graph,
as expressed in (1).
a = O1 → a → O2
B. Defining Sequence of Actions
A sequence of actions can be defined by two methods: 1)
use explicit objects to create a co nnection; and 2) use implicit
objects to create a connection.
The former method uses the input and output objects
explicitly defined in an action to create a co nnection between
two actions. For example,
01 action a 05 action b
02 O3
04 end 08 end
Hence, a sequence of actions can be derived as stated in (2):
a = O1 → a → O2
b = O2 → b → O3
then a . b = O1 → a → O2 → b → O3
The latter method provides the alternative grammar to
reduce the complexity of ADL scripts by defining a sequence
of actions directly without specifying the binding object, or the
implicit object is used to create a connection. For example,
01 action a 05 -> O3
02 b
04 action b
The line 07 defines a sequ ence of actio ns with the implicit
object that is created and bound to the output of action a and
the input of action b. The result is tantamount to (2).
C. Defining Concurrent of Actions
Since the ADL grammar cannot directly describe parallel
behaviors, process algebra [10] is used to replace them with
sequential behaviors as expressed in (3).
(a . b) || (a . c) = a . (b || c)
Given a script containing concurrent of actions as follows:
01 action a 07 -> O3
02 O2 09 action c
04 end 10 O4
06