Template:— task_dependency (tsk_depd)
Context:— UK_Defence

Date: 2009/04/17 12:22:13
Revision: 1.2

Cover Contents Description Bus. perspective Bus. obj.Model diags.Input params.Ref. params.Instantiation path Instance diags.Characterizations Issues in situ

This section specifies the template task_dependency.

NOTE The template has been defined in the context of UK_Defence. Refer to the business context for details of related templates.

NOTE An explanation of a template and the associated instantiation path is provided in the Template overview section.

Description

This template describes how to represent a UK_Defence Task Dependency using Task_method_version_relationship.

This represents the relationship between a task and a predecessor task that must be completed, before the task can be started

Business perspective

The Task dependency business object is used by those UK_Defence Data Exchange Specifications that require information about task dependency.

Business object definition

Figure 1 — Graphical Representation for Business Object Task Dependency

Task Dependency:

This template encompasses the requirements of a UK_Defence Task Dependency.

The definition of a UK_Defence Task Dependency object is:

This information object represent the relationship between a task and a predecessor task that must be completed, before the task can be started. The record consists of the attributes for a task dependency; listed below.

Attribute name	Attribute description	Attribute type	Optionality
ID	This is the identifier of the task dependency	Identifier	Mandatory
Predecessor Task	This is the reference to the task which needs to be completed before the related task can start.	Task	Mandatory
Related Task	This is the reference to the task that is dependent on the predecessor task having been completed before it can start.	Task	Mandatory

Table 1 — Task Dependency attribute details

Model diagrams

The EXPRESS-G diagram in Figure 2 shows the templates and EXPRESS entities that are required to represent the template "task_dependency". The text highlighted in blue shows the template parameters.

Figure 2 — An EXPRESS-G representation of the Information model for task_dependency

The graphic for the template to be used in other EXPRESS-G diagrams is shown in Figure 3 below.

Figure 3 — The graphical representation of the task_dependency template

Input parameters

The following input parameters are defined for this template:

ID (Type='STRING')

Current identifier of the task dependency.

source_organization (Type='STRING', Optional)

The organization or information system that created the associated task dependency identifier. Alternatively this could be set to /NULL and when Person or Information System is the source; see Identifier template characterizations

type (Type='CLASS')

This is the name of the type of the class used to classify the task dependency identifier and so provide the role or reason for the identification.

The following classes and their sub-classes can be used:

classifications: "Identifier_type" (urn:plcs:rdl:std:Identifier_type)

predecessor_task (Type= 'ENTITY (Task_method_version)' )

Identifies the task which needs to be completed before the related task can start.

related_task (Type= 'ENTITY (Task_method_version)' )

Identifies the task that is dependent on the predecessor task having been completed before it can start.

Reference parameters

The following reference parameters are defined for this template:

task(Type='ENTITY (Identification_assignment)')

Allow the Identification_assignment entity instantiated in this path to be referenced when this template is used.

Note: The Identification_assignment entity can be referenced in a template path by:

%^target = $task_dependency.task%

where target is the parameter to which the Identification_assignment is bound.

Uniqueness constraints

The following parameter combinations specify a uniqueness constraint:

Unique constraint: Unique task dependency

Each instance of the entity (Identification_assignment) within the data set shall be uniquely identified by a combination of the following parameters on this template (task_dependency) namely: ID, predecessor_task, related_task.
The instance is referenced by the following template parameter: task.

Instantiation path

The instantiation path shown below specifies the entities that are to be instantiated by the template.

A description of templates and the syntax for the instantiation path is provided in the Templates Help/Information section.

Task_method_version_relationship

-- Mark the Task_method_version_relationship entity as
-- referable when this template is used by binding it to the reference
-- parameter task_ver_rel
%^task_ver_rel = Task_method_version_relationship%
Task_method_version_relationship.name = '/IGNORE'
Task_method_version_relationship.description = '/IGNORE'
Task_method_version_relationship.relating_method -> @predecessor_task
Task_method_version_relationship.related_method -> @related_task

-- instantiate the task_dependency identifier
/identifier(
    ID=@ID,
    source_organization=@source_organization,
    type=@type,
    items=^task_ver_rel)/

The following entities are instantiated with attributes as specified:

Entity in path	Value	Inherited from
Task_method_version_relationship.name	'/IGNORE'	Activity_method_relationship.name
Task_method_version_relationship.description	'/IGNORE'	Activity_method_relationship.description

Instance diagrams

The instance diagram in Figure 4 shows an example of the EXPRESS entities and templates that are instantiated by the template:

/task_dependency(predecessor_task='@122', related_task='@1', id='TD1234', source_organization='BAE Systems', type='Task_method_identification_code')/

(an illustration of the consolidated task_dependency template is shown in Figure 5 below.)

Figure 4 — Entities instantiated by task_dependency template

The instance diagram in Figure 5 shows the graphic symbol for the template that is to be used in other instance diagrams. The example template is:

/task_dependency(predecessor_task='@122', related_task='@1', id='TD1234', source_organization='BAE Systems', type='Task_method_identification_code')/

Figure 5 — Instantiation of task_dependency template

Characterizations

No common characterizations of the template task_dependency have been identified. However, the ISO 10303-239 EXPRESS model may enable other assignments to the entities instantiated by the template.