Template: 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 PSMTemplate objects instantiated by the Requirement template.

The specification comprises the following sections:

Section Description provides a description of the template;
Section Template Block specifies the SysML Block that represents the template;
Section Template Properties specifies the properties, i.e. the SysML Part, Reference and Value properties of the templates SysML Block;
Section Template Output Ports specifies the SysML Output Ports of the templates SysML Block. These bind to the templates and PLCS PSM objects instantiated by the Requirement template as described in section Template Parametric Diagram;
Section Template Constraints specifies the constraints on PLCS PSMTemplate objects instantiated by the Requirement template;
Section Template Parametric Diagram specifies the templates and PLCS PSMTemplate objects instantiated by the Requirement template;
Section Instantiated blocks specifies the templates and PLCS PSMTemplate objects instantiated by the Requirement template and bound to private parts of the template;
Section Default instances species the instances that have been instantiated in the template. These are used to set the default value of blocks.
Section Constraint blocks identifies the constraint blocks that have been specified in this template;
Section Example data provides example XML data sets that have been instantiated in accordance with this template.

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

Description

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.

../../../../../data/PLCS/psm_model/images/SysML_Block_Definition_Diagram__Diagrams__Requirements.png

Figure 1 - Requirements model

Related Templates

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.

Template Block

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

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

The SysML Parametric diagrams for the template Block are shown in template parametric diagram section.

Figure 2 - Template block definition diagram for Requirement

Template Properties

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

References:

context [0..1] (Template: OASIS:ViewDefinitionContext)

The view definition context for the requirement.

Parts:

identifications [1..*] (Template: OASIS:Identification)

Identifiers used to identify the requirement

versionIds [0..*] (Template: OASIS:Identification)

Optional version identifiers for this requirement.

classifications [0..*] (Template: OASIS:Classifier)

The classifications of 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.

Template Output Ports

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.

Template constraints

The following constraints are defined for this template:

Constraint: restrictPropertyDefinition

Specification: (English)

ExternalPropertyDefinition is restricted to: http://docs.oasis-open.org/plcs/ns/plcslib/v1.0/data/contexts/OASIS/refdata/plcs-rdl#Requirement_definition

Template Parametric diagram

This section describes the template's Parametric Diagram. The diagram details the pattern of templates and PLCS PSMTemplate 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 a Parametric Diagram.

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

Figure 3 - Parametric diagram for Requirement

Instantiated Blocks

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)

Default instances

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

Figure 3 - Model instance diagram for Requirement

Instances

The following instances have been created:

owlObjRequirement_definition instance of Block: Ap239Ap233Psm:ExternalOwlObject.

ExternalOwlObject.individual = http://docs.oasis-open.org/plcs/ns/plcslib/v1.0/data/contexts/OASIS/refdata/plcs-rdl#Requirement_definition

Constraint Blocks

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.

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.

Example data

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

Data set: Requirement

Requirement

requirement.xml

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This example shows the XML instantiated to represent a Requirement.