Template: OASIS:Requirement

This section specifies the template Requirement.

The specification comprises a SysML Block that represents the template and an associated Parametric Diagram that defines the templates and PLCS PSM objects instantiated by the Requirement template.

The specification comprises the following sections:

NOTE    An explanation of a template and its specification is provided in the Template overview

The Requirement template describes how to represent a statement of need that should be met by the product or system to which the requirement is allocated.

The SysML Block Definition diagram in Figure 1 shows how a Part is represented in the PLCS PSM.

Figure 1 -  Requirements model

No templates have been explicitly defined as being related to the Requirement template.

NOTE    The Requirement template may make reference to other templates as part of the Parametric Diagram. These are not listed here.

Figure 2 shows the SysML Block that represents the template. The Block is an abstraction representing a pattern of templates and PLCS PSM objects.

The properties, i.e. the SysML Block Part, Reference and Value properties, of the template's SysML Block are described in the Template Properties section.

The output ports shown on the template's SysML Block are described in the template output ports section.

Figure 2 -  Template block definition diagram for Requirement

The following Part, Reference, and Value properties are defined for this template:

References:
context [0..1] (Template: OASIS:ViewDefinitionContext)
The view definition context for the requirement.
classifications [0..*] (Template: OASIS:Classifier)
The classifications of this requirement.
Parts:
identifications [1..*] (Template: OASIS:Identification)
Identifiers used to identify the requirement
versionIds [0..*] (Template: OASIS:Identification)
Optional version identifiers for this requirement.
propertyDefinition [0..1] (Block: Ap239Ap233Psm:ValueWithUnit)
The definition of the requirement as a property.
textDefinition [0..1] (Block: Ap239Ap233Psm:LocalizedString)
The textual representation of the requirement.

The following output ports are defined for this template:

req (Block: Ap239Ap233Psm:Requirement)
Enables the Block: Ap239Ap233Psm:Requirement instantiated by this template to be referenced when the template is used.
reqVersion (Block: Ap239Ap233Psm:RequirementVersion)
Enables the Block: Ap239Ap233Psm:RequirementVersion instantiated by this template to be referenced when the template is used.
reqView (Block: Ap239Ap233Psm:RequirementViewDefinition)
Enables the Block: Ap239Ap233Psm:RequirementViewDefinition instantiated by this template to be referenced when the template is used.

There are no constraints defined for this template.

This section describes the template's Parametric Diagram. The diagram details the pattern of templates and PLCS PSM objects that are required to represent the template Requirement.

The public properties, i.e. those visible in the template's SysML block (See Figure 2) are shown on the left of a Parametric Diagram.

NOTE    Restrictions on the reference data to be set on the public properties is defined in the Template Properties section.

The output ports are shown on the right of the Parametric Diagram.

PLCS PSM objects are shaded khaki and template shaded light green in a Parametric Diagram.

Figure 3 -  Parametric diagram for Requirement

The following blocks are instantiated by this template and bound to private parts of the template as shown in the Parametric Diagram section:

Private Part Property:requirement [1] (Block: Ap239Ap233Psm:Requirement)
Private Part Property:reqVersion [0..1] (Block: Ap239Ap233Psm:RequirementVersion)
Private Part Property:reqView [0..1] (Block: Ap239Ap233Psm:RequirementViewDefinition)
Private Reference Property:definitionalProp [0..1] (Block: Ap239Ap233Psm:ExternalPropertyDefinition)

The following constraint, normally a uniqueness constraint, is applicable when instantiating the ExternalPropertyDefinition:

rule.Ap239Ap233Psm.ExternalOwlClass.ur1
Constraint: UR1
Specification: (OCL2.0)
ExternalPropertyDefinition::allInstances()->isUnique(definition)
Private Part Property:theText [1] (Block: Ap239Ap233Psm:StringValue)
Private Part Property:combineReqDfns [1] ( Constraint Block: OASIS:Requirement:CombineReqDfns)
Private Reference Property:owlObj [0..1] (Block: Ap239Ap233Psm:ExternalOwlObject)

The following constraint, normally a uniqueness constraint, is applicable when instantiating the ExternalOwlObject:

rule.Ap239Ap233Psm.ExternalOwlClass.ur1
Constraint: ur1
Specification: (OCL2.0)
ExternalOwlObject::allInstances()->isUnique(individual)
Private Reference Property:proxy [0..1] (Block: Ap239Ap233Psm:Proxy)

Figure 3 shows the instances that have been instantiated in the template. These are used to set the default value of blocks.

Instance diagram
Figure 3 -  Model instance diagram for Requirement

The following instances have been created:

Figure 3 shows the constraint blocks that have been created in the template.

Constraint Blocks are typically used to combine blocks into a collection that can then be bound to a property. For example, combining a set of identifications that can then be bound to property of type Identification.

Constraints diagram
Figure 3 -  Constraint block diagram for Requirement

The following constraint blocks have been created:

Constraint: CombineReqDfns
Specification: (OCL2.0)
combined=propVal1->union(propVal2,propVal3,propVal4)
a constraint block that creates a collection that is the union of objects of type PropertyValues.

The following section provides an example XML dataset that has been instantiated in accordance with this template.

Data set: Requirement

Requirement requirement.xml View download

This example shows the XML instantiated to represent a Requirement.