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Conference DSL

Design the metamodel of a DSL for modelling conferences using Emfatic. Below are key concepts and relationships your language must support.

  • A conference runs over several days
  • On every day, there are several talks organised in (potentially parallel) tracks
  • There are breaks between tracks (e.g., for lunch/coffee)
  • Each track/break takes place in one room
  • Each talk is delivered by one speaker
  • Each talk also has a pre-arranged discussant, whose role is to provide critical feedback
  • Each talk has a pre-defined duration

Why?

  • To ensure that the conference program is clash-free e.g.
    • Parallel tracks happen in different rooms
    • The total duration of the talks of a track does not exceed the duration of the track
    • Breaks don’t overlap with tracks
  • To generate booklets, web-pages etc. from the program in a consistent manner instead of maintaining them manually (and risking inconsistency)

Solution

Try to design your own metamodel before you check out the solution below (or download the solution ZIP).

@namespace(uri="conference", prefix="")
package conference;

class Conference{
	val Person[*] participants;
	val Room[*] rooms;
	val Day[*] days;
}

class Person {
	attr String fullName;
	attr String affiliation;
}

class Day {
	attr String name;
	val Slot[*] slots;
}

abstract class Slot {
	attr String start;
	attr String end;
	ref Room room;
}

class Break extends Slot {
	attr String reason;
}

class Track extends Slot {
	attr String title;
	val Talk[*] talks;
}

class Talk {
	attr String title;
	attr int duration;
	ref Person speaker;
	ref Person discussant;
}

class Room {
	attr String name;
}

A diagrammatic representation of the metamodel above can be found below.

Diagrammatic representation of the Conference DSL metamodel

Notes on the solution

  • This is only one possible solution. If your solution is not identical it does not mean that it is incorrect.
    • If you have any questions, please ask!
  • The name of meta-class Slot appears in italics because it is an abstract class (i.e. it cannot be instantiated)
  • References that start with a black diamond (val in Emfatic) are containment references
    • A talk can appear only under one track
    • A track can appear only under one day
    • Another way to think about it
      • If we delete a track, all its contained talks should be deleted with it
  • References that don’t start with a black diamond (ref in Emfatic) are non-containment references
    • Many slots can share the same room
    • Many talks can be given by the same speaker
    • Another way to think about it
      • Deleting a track should not cause the deletion of the respective room from the model
      • Deleting a talk should not cause the deletion of the respective speaker
  • There are two “artificial” containment references in the model to keep EMF happy
    • Conference.participants
    • Conference.rooms
  • In the absence of these references, Person and Room instances could not be contained anywhere in the model and would have to appear as top-level elements EMF-based tools don’t like models with multiple top-level elements
    • Hence we need to introduce these references so that all model elements can be contained somewhere under a root Conference model element

Create a conference model

Create a model that conforms to the conference metamodel and exercises all its features at least once (i.e. instantiates all classes, contains values for all attributes/references) using the tree-based EMF editor or using Flexmi.

Solution

Here is a sample model (contained in the model solution) that conforms to the Conference DSL.

<?xml version="1.0" encoding="ASCII"?>
<Conference xmi:version="2.0" xmlns:xmi="http://www.omg.org/XMI" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns="conference" xmi:id="_e-mNEObZEe-uj-1n3DNKPg">
  <participants xmi:id="_e-mNEebZEe-uj-1n3DNKPg" fullName="Person 1" affiliation="University 1"/>
  <participants xmi:id="_e-mNEubZEe-uj-1n3DNKPg" fullName="Person 2" affiliation="University 2"/>
  <participants xmi:id="_e-mNE-bZEe-uj-1n3DNKPg" fullName="Person 3" affiliation="University 3"/>
  <participants xmi:id="_e-mNFObZEe-uj-1n3DNKPg" fullName="Person 4" affiliation="University 4"/>
  <participants xmi:id="_e-mNFebZEe-uj-1n3DNKPg" fullName="Person 5" affiliation="University 5"/>
  <participants xmi:id="_e-mNFubZEe-uj-1n3DNKPg" fullName="Person 6" affiliation="University 6"/>
  <participants xmi:id="_e-mNF-bZEe-uj-1n3DNKPg" fullName="Person 7" affiliation="University 7"/>
  <participants xmi:id="_e-mNGObZEe-uj-1n3DNKPg" fullName="Person 8" affiliation="University 8"/>
  <participants xmi:id="_e-mNGebZEe-uj-1n3DNKPg" fullName="Person 9" affiliation="University 9"/>
  <participants xmi:id="_e-mNGubZEe-uj-1n3DNKPg" fullName="Person 10" affiliation="University 10"/>
  <rooms xmi:id="_e-mNG-bZEe-uj-1n3DNKPg" name="Room 1"/>
  <rooms xmi:id="_e-mNHObZEe-uj-1n3DNKPg" name="Room 2"/>
  <rooms xmi:id="_e-mNHebZEe-uj-1n3DNKPg" name="Room 3"/>
  <rooms xmi:id="_e-mNHubZEe-uj-1n3DNKPg" name="Room 4"/>
  <days xmi:id="_e-mNH-bZEe-uj-1n3DNKPg" name="Day 1">
    <slots xsi:type="Track" xmi:id="_e-mNIObZEe-uj-1n3DNKPg" start="09:00" end="12:30" room="_e-mNHubZEe-uj-1n3DNKPg" title="Morning">
      <talks xmi:id="_e-mNIebZEe-uj-1n3DNKPg" title="Talk 1" duration="20" speaker="_e-mNE-bZEe-uj-1n3DNKPg" discussant="_e-mNF-bZEe-uj-1n3DNKPg"/>
      <talks xmi:id="_e-mNIubZEe-uj-1n3DNKPg" title="Talk 2" duration="20" speaker="_e-mNEubZEe-uj-1n3DNKPg" discussant="_e-mNEubZEe-uj-1n3DNKPg"/>
      <talks xmi:id="_e-mNI-bZEe-uj-1n3DNKPg" title="Talk 3" duration="20" speaker="_e-mNEubZEe-uj-1n3DNKPg" discussant="_e-mNFObZEe-uj-1n3DNKPg"/>
      <talks xmi:id="_e-mNJObZEe-uj-1n3DNKPg" title="Talk 4" duration="20" speaker="_e-mNEebZEe-uj-1n3DNKPg" discussant="_e-mNE-bZEe-uj-1n3DNKPg"/>
      <talks xmi:id="_e-mNJebZEe-uj-1n3DNKPg" title="Talk 5" duration="20" speaker="_e-mNGubZEe-uj-1n3DNKPg" discussant="_e-mNGebZEe-uj-1n3DNKPg"/>
    </slots>
    <slots xsi:type="Break" xmi:id="_e-mNJubZEe-uj-1n3DNKPg" start="12:30" end="14:00" room="_e-mNG-bZEe-uj-1n3DNKPg" reason="Lunch"/>
    <slots xsi:type="Track" xmi:id="_e-mNJ-bZEe-uj-1n3DNKPg" start="14:00" end="17:00" room="_e-mNHebZEe-uj-1n3DNKPg" title="Afternoon">
      <talks xmi:id="_e-mNKObZEe-uj-1n3DNKPg" title="Talk 6" duration="20" speaker="_e-mNGObZEe-uj-1n3DNKPg" discussant="_e-mNFubZEe-uj-1n3DNKPg"/>
      <talks xmi:id="_e-mNKebZEe-uj-1n3DNKPg" title="Talk 7" duration="20" speaker="_e-mNFubZEe-uj-1n3DNKPg" discussant="_e-mNEubZEe-uj-1n3DNKPg"/>
      <talks xmi:id="_e-mNKubZEe-uj-1n3DNKPg" title="Talk 8" duration="20" speaker="_e-mNF-bZEe-uj-1n3DNKPg" discussant="_e-mNE-bZEe-uj-1n3DNKPg"/>
      <talks xmi:id="_e-mNK-bZEe-uj-1n3DNKPg" title="Talk 9" duration="20" speaker="_e-mNF-bZEe-uj-1n3DNKPg" discussant="_e-mNFubZEe-uj-1n3DNKPg"/>
      <talks xmi:id="_e-mNLObZEe-uj-1n3DNKPg" title="Talk 10" duration="20" speaker="_e-mNEubZEe-uj-1n3DNKPg" discussant="_e-mNF-bZEe-uj-1n3DNKPg"/>
    </slots>
  </days>
  <days xmi:id="_e-mNLebZEe-uj-1n3DNKPg" name="Day 2">
    <slots xsi:type="Track" xmi:id="_e-mNLubZEe-uj-1n3DNKPg" start="09:00" end="12:30" room="_e-mNHObZEe-uj-1n3DNKPg" title="Morning">
      <talks xmi:id="_e-mNL-bZEe-uj-1n3DNKPg" title="Talk 11" duration="20" speaker="_e-mNGubZEe-uj-1n3DNKPg" discussant="_e-mNFebZEe-uj-1n3DNKPg"/>
      <talks xmi:id="_e-mNMObZEe-uj-1n3DNKPg" title="Talk 12" duration="20" speaker="_e-mNF-bZEe-uj-1n3DNKPg" discussant="_e-mNGebZEe-uj-1n3DNKPg"/>
      <talks xmi:id="_e-mNMebZEe-uj-1n3DNKPg" title="Talk 13" duration="20" speaker="_e-mNFubZEe-uj-1n3DNKPg" discussant="_e-mNF-bZEe-uj-1n3DNKPg"/>
      <talks xmi:id="_e-mNMubZEe-uj-1n3DNKPg" title="Talk 14" duration="20" speaker="_e-mNFebZEe-uj-1n3DNKPg" discussant="_e-mNEubZEe-uj-1n3DNKPg"/>
      <talks xmi:id="_e-mNM-bZEe-uj-1n3DNKPg" title="Talk 15" duration="20" speaker="_e-mNGObZEe-uj-1n3DNKPg" discussant="_e-mNFubZEe-uj-1n3DNKPg"/>
    </slots>
    <slots xsi:type="Break" xmi:id="_e-mNNObZEe-uj-1n3DNKPg" start="12:30" end="14:00" room="_e-mNHObZEe-uj-1n3DNKPg" reason="Lunch"/>
    <slots xsi:type="Track" xmi:id="_e-mNNebZEe-uj-1n3DNKPg" start="14:00" end="17:00" room="_e-mNHebZEe-uj-1n3DNKPg" title="Afternoon">
      <talks xmi:id="_e-mNNubZEe-uj-1n3DNKPg" title="Talk 16" duration="20" speaker="_e-mNFObZEe-uj-1n3DNKPg" discussant="_e-mNGubZEe-uj-1n3DNKPg"/>
      <talks xmi:id="_e-mNN-bZEe-uj-1n3DNKPg" title="Talk 17" duration="-10" speaker="_e-mNGebZEe-uj-1n3DNKPg" discussant="_e-mNEubZEe-uj-1n3DNKPg"/>
      <talks xmi:id="_e-mNOObZEe-uj-1n3DNKPg" title="Talk 18" duration="20" speaker="_e-mNGubZEe-uj-1n3DNKPg" discussant="_e-mNF-bZEe-uj-1n3DNKPg"/>
      <talks xmi:id="_e-mNOebZEe-uj-1n3DNKPg" title="Talk 19" duration="20" speaker="_e-mNFebZEe-uj-1n3DNKPg" discussant="_e-mNEebZEe-uj-1n3DNKPg"/>
      <talks xmi:id="_e-mNOubZEe-uj-1n3DNKPg" title="Talk 20" duration="20" speaker="_e-mNF-bZEe-uj-1n3DNKPg" discussant="_e-mNGubZEe-uj-1n3DNKPg"/>
    </slots>
  </days>
  <days xmi:id="_e-mNO-bZEe-uj-1n3DNKPg" name="Day 3">
    <slots xsi:type="Track" xmi:id="_e-mNPObZEe-uj-1n3DNKPg" start="12:30" end="09:00" room="_e-mNHubZEe-uj-1n3DNKPg" title="Morning">
      <talks xmi:id="_e-mNPebZEe-uj-1n3DNKPg" title="Talk 21" duration="20" speaker="_e-mNGebZEe-uj-1n3DNKPg" discussant="_e-mNGubZEe-uj-1n3DNKPg"/>
      <talks xmi:id="_e-mNPubZEe-uj-1n3DNKPg" title="Talk 22" duration="20" speaker="_e-mNFubZEe-uj-1n3DNKPg" discussant="_e-mNGebZEe-uj-1n3DNKPg"/>
      <talks xmi:id="_e-mNP-bZEe-uj-1n3DNKPg" title="Talk 23" duration="20" speaker="_e-mNFubZEe-uj-1n3DNKPg" discussant="_e-mNGebZEe-uj-1n3DNKPg"/>
      <talks xmi:id="_e-mNQObZEe-uj-1n3DNKPg" title="Talk 24" duration="20" speaker="_e-mNEubZEe-uj-1n3DNKPg" discussant="_e-mNGebZEe-uj-1n3DNKPg"/>
      <talks xmi:id="_e-mNQebZEe-uj-1n3DNKPg" title="Talk 25" duration="20" speaker="_e-mNF-bZEe-uj-1n3DNKPg" discussant="_e-mNFebZEe-uj-1n3DNKPg"/>
    </slots>
    <slots xsi:type="Break" xmi:id="_e-mNQubZEe-uj-1n3DNKPg" start="12:30" end="14:00" room="_e-mNHObZEe-uj-1n3DNKPg" reason="Lunch"/>
    <slots xsi:type="Track" xmi:id="_e-mNQ-bZEe-uj-1n3DNKPg" start="14:00" end="17:00" room="_e-mNHubZEe-uj-1n3DNKPg" title="Afternoon">
      <talks xmi:id="_e-mNRObZEe-uj-1n3DNKPg" title="Talk 26" duration="20" speaker="_e-mNGubZEe-uj-1n3DNKPg" discussant="_e-mNF-bZEe-uj-1n3DNKPg"/>
      <talks xmi:id="_e-mNRebZEe-uj-1n3DNKPg" title="Talk 27" duration="20" speaker="_e-mNGObZEe-uj-1n3DNKPg" discussant="_e-mNF-bZEe-uj-1n3DNKPg"/>
      <talks xmi:id="_e-mNRubZEe-uj-1n3DNKPg" title="Talk 28" duration="20" speaker="_e-mNGubZEe-uj-1n3DNKPg" discussant="_e-mNEebZEe-uj-1n3DNKPg"/>
      <talks xmi:id="_e-mNR-bZEe-uj-1n3DNKPg" title="Talk 29" duration="20" speaker="_e-mNGubZEe-uj-1n3DNKPg" discussant="_e-mNE-bZEe-uj-1n3DNKPg"/>
      <talks xmi:id="_e-mNSObZEe-uj-1n3DNKPg" title="Talk 30" duration="20" speaker="_e-mNE-bZEe-uj-1n3DNKPg" discussant="_e-mNEubZEe-uj-1n3DNKPg"/>
    </slots>
  </days>
</Conference>