Issue 7723: Empty Interfaces in PLM Services Specification dtc/04-05-05 (plm-ftf) Source: PROSTEP AG (Dr. Lutz Laemmer, lutz.laemmer@prostep.com Lutz.Laemmer@PROSTEP.com laemmer@prostep.de laemmer@prostep.com) Nature: Uncategorized Issue Severity: Summary: In several places in the model, there are classes that have both realization and association relationships with interfaces. An example is the Specification_expression class that holds association and realization relationships with the Specification_operand_select interface. The PLM Adopted Specification (OMG document dtc/04-05-05) in its section 7.7.12 describes the PLM Configuration Management Package. In it, figure 104 illustrates the association relationship between the Specification_expression and the Specification_operand_select. Later in section 7.7.12.42 the interface Specification_operand_select is defined as: " This empty interface is defined to provide a placeholder for the following classes: Specification_expression and Specification" The realization relationhsip between a class and an interface is perfectly clear to me. It is the association relationships that "provides a placeholder" that I cannot understand. Does it mean that such a placeholder is an instance of an element that implements the interface? Resolution: Revised Text: Resolution: The Specification_operand_select participates both in - an association to Specification and - as an relationship between Specification_inclusions An Specification_operand_select may not be instantiated but is always realized as either Specification_expression or Specification, which is descibed as a "placeholder for instances of Specification_expression and Specification" as roles in that relationship. The empty interface does not have any other purpose but to mark the two classes to participate in that relationship. Revised Text: Change all occurrences of the phrase: This empty interface is defined to provide a placeholder for the following to This empty interface is realized by the following classes: Actions taken: September 9, 2004: received issue August 1, 2005: closed issue Discussion: End of Annotations:===== ubject: Empty Interfaces in PLM Services Specification dtc/04-05-05 Date: Thu, 9 Sep 2004 07:43:10 +0200 X-MS-Has-Attach: X-MS-TNEF-Correlator: Thread-Topic: Empty Interfaces in PLM Services Specification dtc/04-05-05 Thread-Index: AcSWL+Ozp6kdLM1gRF+C885KhMfGZw== From: "Lämmer, Lutz" To: X-MIME-Autoconverted: from quoted-printable to 8bit by amethyst.omg.org id i895wp1U011784 -----Ursprüngliche Nachricht----- Von: Juan Pablo Zamora Zapata [mailto:jpzzapat@yahoo.com] Gesendet: Mi 25.08.2004 15:08 An: Lämmer, Lutz Betreff: Re: AW: Empty interfaces in PLM specification Let me see if I got it right: - An Specification, being a characteristic of a product, may contain 0 or many Specification_inclusions (expressed by a composition relationship between Specification and Specification_inclusion with multiplicity 0..* in Figure 104 page 208 and textually described in section 7.7.12.34 page. 294) - An Specification_inclusion holds a reference (using the role of Included_specification) to one instance of an element that might be of type Specification or of type Specification_expression (expressed by an association relationship between Specification_inclusion and the interface Specification_operand_select in Figure 104 page 208 and textually described in section 7.7.12.38 page. 296) - An Specification_expression holds a reference (using the role of operand) to one or many instances of element that might be of type Specification or of type Specification_expression (expressed by an association relationship between Specification_expression and the interface Specification_operand_select in Figure 104 page 208 and textually described in section 7.7.12.37 page. 296) I'll would also like to point to section 7.7.12.39 which I think is a typo. It think that it should be the associations subsection of 7.7.12.38 that talks about Specification_inclusion. Thanks again! Juan Pablo Zamora Zapata "Lämmer,_Lutz" wrote: Juan, The Specification_operand_select participates both in - an association to Specification and - as an relationship between Specification_inclusions An Specification_operand_select may not be instantiated but is always realized as either Specification_expression or Specification, which is descibed as a "placeholder for instances of Specification_expression and Specification" as roles in that relationship. The empty interface does not have any other purpose but to mark the two classes to participate in that relationship. Regards, Lutz Laemmer -----Ursprüngliche Nachricht----- Von: Juan Pablo Zamora Zapata [mailto:jpzzapat@yahoo.com] Gesendet: Mi 25.08.2004 00:02 An: Lämmer, Lutz Betreff: Empty interfaces in PLM specification Hello Dr.Lutz Lämme! In several places in the model, there are classes that have both realization and association relationships with interfaces. An example is the Specification_expression class that holds association and realization relationships with the Specification_operand_select interface. The PLM Adopted Specification (OMG document dtc/04-05-05) in its section 7.7.12 describes the PLM Configuration Management Package. In it, figure 104 illustrates the association relationship between the Specification_expression and the Specification_operand_select. Later in section 7.7.12.42 the interface Specification_operand_select is defined as: " This empty interface is defined to provide a placeholder for the following classes: Specification_expression and Specification" The realization relationhsip between a class and an interface is perfectly clear to me. It is the association relationships that "provides a placeholder" that I cannot understand. Does it mean that such a placeholder is an instance of an element that implements the interface? I'll appreciate if you can help me to understand this matter. Thanks a lot in advanced. Best Regards, Juan Pablo Zamora Zapata School of Computer Science Carleton University Ottawa, Canada