Modeling on the Right Side of the Brain

Since your first web application, you have struggled with identifying domain objects. Assigning business rules and services appears to be a talent that only other developers are born with. Fear not! Object Modeling is a learnable, teachable skill. This talk demonstrates the five essential skills you need for modeling objects and their responsibilities. Think beyond ActiveRecord and your database, and learn how color and patterns will help you explain, maintain and extend your application.

Transcript

4. Edges Spaces Relationships Lights/Shadows Gestalt
5. Modeling on the Right Side of the Brain An introduction to the five basic skills of Object Modeling ! Nicholas Henry #motrsb
6. Objects Collaborations Business Rules Services Attributes
7. Anatomy of Domain Model
8. Anatomy of Domain Model
9. Anatomy of Domain Model
10. Anatomy of Domain Model
11. Other Concerns
12. Heart of your Application
14. User Stories Rails Application The Gap ?
15. Use Object Modeling to bridge the gap between User Stories and implementing Domain Models
17. NO BIG UPFRONT DESIGN
18. Objects have responsibilities
19. Objects have responsibilities
20. Objects have responsibilities
21. Objects have responsibilities
22. Objects have responsibilities
23. Collaborations Business Rules Services Attributes Finding Objects
24. Collaborations Solution Challenge
25. Archetypes
26. Event Archetype
27. Event Archetype
28. Role Archetype
29. Party-Place-Thing Archetype
30. Description Archetype
31. makeMomentInterval addDetail calcTotal recalcTotal complete cancel mi_generateNext mi_assessWRTPrior mi_assessWRTNext mi_comparePlanVsActual listMIs assessAcrossMIs «moment-interval» MomentInterval number dateOrDateTimeOrInterval priority total status «moment-interval» NextMI «moment-interval» PriorMI calcTotal qty «mi-detail» MomentIntervalDetail 0..* 1 0..* 1 Interacts - With its pink mi-details - With its pink prior moment-intervals - With its pink next moment-intervals - With its corresponding yellow roles, green party/place/things, or blue descriptions plan 0..* actual 0..1 1 1..* makeMomentInterval interface «plug-in point» IMakeMomentInterval 1 assessAcrossMIs listMIs listRoles accessAcrossRoles assignedNumber status «role» ThingRole assessAcrossMIs listMIs listRoles accessAcrossRoles assignedNumber status «role» PlaceRole assessAcrossMIs listMIs listRoles accessAcrossRoles assignedNumber status «role» PartyRole 0..* 1 0..* 1 0..* 0..* assessAcrossRoles getCustomElseDefaultValue listRoles listThings assessAcrossThings serialNumber name address customerValue «thing» Thing assessAcrossRoles getCustomElseDefaultValue listRoles listPlaces assessAcrossPlaces serialNumber name address customerValue «place» Place assessWithPlugInElseDefault accessAcrossPlaces findAvailable calcQtyAvailable calcTotalFor listPlaces listDescs accessAcrossDescs type description itemNumber defaultNumber «description» PlaceDescription 0..* 1 assess interface «plug-in point» IAssess assessWithPlugInElseDefault accessAcrossThings findAvailable calcQtyAvailable calcTotalFor listThings listDescs accessAcrossDescs type description itemNumber defaultNumber «description» ThingDescription 0..* 1 assess interface «plug-in point» IAssess assessWithPlugInElseDefault accessAcrossParties findAvailable calcQtyAvailable calcTotalFor listParties listDescs accessAcrossDescs type description itemNumber defaultNumber «description» PartyDescription 0..* 1 assess interface «plug-in point» IAssess assessAcrossRoles getCustomElseDefaultValue listRoles listParties assessAcrossThings serialNumber name address customerValue «party» Party Interacts with its yellow roles or its pink moment-intervals Interacts with its green parties or its pink moment-intervals Interacts with its pink moment-intervals 1 0..* 0..1 0..1 1 0..* 1 0..* 0..1 The domain-neutral component. If you do not need to track a specific green, then drop the been and the yellow; the blue is enough. If just one hello for a green, keep the portioning if useful, else drop the yellow. If you do not need to track a specific green, then drop the been and the yellow; the blue is enough. If just a category attribute, move the attribute to the green and drop the blue.
32. Archetypes
33. Archetypes
34. Archetypes
35. Archetypes
36. Archetypes
37. makeMomentInterval addDetail calcTotal recalcTotal complete cancel mi_generateNext mi_assessWRTPrior mi_assessWRTNext mi_comparePlanVsActual listMIs assessAcrossMIs «moment-interval» MomentInterval number dateOrDateTimeOrInterval priority total status «moment-interval» NextMI «moment-interval» PriorMI calcTotal qty «mi-detail» MomentIntervalDetail 0..* 1 0..* 1 Interacts - With its pink mi-details - With its pink prior moment-intervals - With its pink next moment-intervals - With its corresponding yellow roles, green party/place/things, or blue descriptions plan 0..* actual 0..1 1 1..* makeMomentInterval interface «plug-in point» IMakeMomentInterval 1 assessAcrossMIs listMIs listRoles accessAcrossRoles assignedNumber status «role» ThingRole assessAcrossMIs listMIs listRoles accessAcrossRoles assignedNumber status «role» PlaceRole assessAcrossMIs listMIs listRoles accessAcrossRoles assignedNumber status «role» PartyRole 0..* 1 0..* 1 0..* 0..* assessAcrossRoles getCustomElseDefaultValue listRoles listThings assessAcrossThings serialNumber name address customerValue «thing» Thing assessAcrossRoles getCustomElseDefaultValue listRoles listPlaces assessAcrossPlaces serialNumber name address customerValue «place» Place assessWithPlugInElseDefault accessAcrossPlaces findAvailable calcQtyAvailable calcTotalFor listPlaces listDescs accessAcrossDescs type description itemNumber defaultNumber «description» PlaceDescription 0..* 1 assess interface «plug-in point» IAssess assessWithPlugInElseDefault accessAcrossThings findAvailable calcQtyAvailable calcTotalFor listThings listDescs accessAcrossDescs type description itemNumber defaultNumber «description» ThingDescription 0..* 1 assess interface «plug-in point» IAssess assessWithPlugInElseDefault accessAcrossParties findAvailable calcQtyAvailable calcTotalFor listParties listDescs accessAcrossDescs type description itemNumber defaultNumber «description» PartyDescription 0..* 1 assess interface «plug-in point» IAssess assessAcrossRoles getCustomElseDefaultValue listRoles listParties assessAcrossThings serialNumber name address customerValue «party» Party Interacts with its yellow roles or its pink moment-intervals Interacts with its green parties or its pink moment-intervals Interacts with its pink moment-intervals 1 0..* 0..1 0..1 1 0..* 1 0..* 0..1 The domain-neutral component. If you do not need to track a specific green, then drop the been and the yellow; the blue is enough. If just one hello for a green, keep the portioning if useful, else drop the yellow. If you do not need to track a specific green, then drop the been and the yellow; the blue is enough. If just a category attribute, move the attribute to the green and drop the blue.
38. makeMomentInterval addDetail calcTotal recalcTotal complete cancel mi_generateNext mi_assessWRTPrior mi_assessWRTNext mi_comparePlanVsActual listMIs assessAcrossMIs «moment-interval» MomentInterval number dateOrDateTimeOrInterval priority total status «moment-interval» NextMI «moment-interval» PriorMI calcTotal qty «mi-detail» MomentIntervalDetail 0..* 1 0..* 1 Interacts - With its pink mi-details - With its pink prior moment-intervals - With its pink next moment-intervals - With its corresponding yellow roles, green party/place/things, or blue descriptions plan 0..* actual 0..1 1 1..* makeMomentInterval interface «plug-in point» IMakeMomentInterval 1 assessAcrossMIs listMIs listRoles accessAcrossRoles assignedNumber status «role» ThingRole assessAcrossMIs listMIs listRoles accessAcrossRoles assignedNumber status «role» PlaceRole assessAcrossMIs listMIs listRoles accessAcrossRoles assignedNumber status «role» PartyRole 0..* 1 0..* 1 0..* 0..* assessAcrossRoles getCustomElseDefaultValue listRoles listThings assessAcrossThings serialNumber name address customerValue «thing» Thing assessAcrossRoles getCustomElseDefaultValue listRoles listPlaces assessAcrossPlaces serialNumber name address customerValue «place» Place assessWithPlugInElseDefault accessAcrossPlaces findAvailable calcQtyAvailable calcTotalFor listPlaces listDescs accessAcrossDescs type description itemNumber defaultNumber «description» PlaceDescription 0..* 1 assess interface «plug-in point» IAssess assessWithPlugInElseDefault accessAcrossThings findAvailable calcQtyAvailable calcTotalFor listThings listDescs accessAcrossDescs type description itemNumber defaultNumber «description» ThingDescription 0..* 1 assess interface «plug-in point» IAssess assessWithPlugInElseDefault accessAcrossParties findAvailable calcQtyAvailable calcTotalFor listParties listDescs accessAcrossDescs type description itemNumber defaultNumber «description» PartyDescription 0..* 1 assess interface «plug-in point» IAssess assessAcrossRoles getCustomElseDefaultValue listRoles listParties assessAcrossThings serialNumber name address customerValue «party» Party Interacts with its yellow roles or its pink moment-intervals Interacts with its green parties or its pink moment-intervals Interacts with its pink moment-intervals 1 0..* 0..1 0..1 1 0..* 1 0..* 0..1 If you do not need to track a specific green, then drop the been and the yellow; the blue is enough. If just one hello for a green, keep the portioning if useful, else drop the yellow. If you do not need to track a specific green, then drop the been and the yellow; the blue is enough. If just a category attribute, move the attribute to the green and drop the blue.
40. Archetypes
41. Objects Identifying Collaborations Business Rules Services Attributes
42. VS Collaborations Associations
43. Objects have responsibilities
44. Collaborations Solution Challenge
45. Elementary Collaboration Pattern
46. Example
47. PPT vs Description Archetypes
48. PPT vs Description Archetypes
49. PPT vs Description Archetypes
50. PPT vs Description Archetypes
51. Composite Pattern
52. Follow-up Pattern
53. Example
54. Example
55. Example
56. Example
57. Event Aggregate Pattern
58. Objects Collaborations Defining Business Rules Services Attributes
59. Business Rules Solution Challenge
60. Collaborations require dialog
61. total_weight expedited «event» Shipment max_weight duration «description» ShippingMethod shipment.total_weight <= max_weight Collaborations require dialog
62. total_weight expedited «event» Shipment max_weight duration «description» ShippingMethod expedited? && shipping_method.duration <= 2.days Collaborations require dialog
63. Collaborations require dialog
64. Objects Collaborations Business Rules Assigning Services Attributes
65. Objects have responsibilities
67. Collaborations Solution Challenge
68. Objects perform actions themselves
69. Objects Collaborations Business Rules Services Assigning Attributes
70. Objects have responsibilities
71. Attributes
72. Attributes
73. Attributes
74. User Stories Rails Application The Gap ?
75. User Stories Rails Application Object Modeling
76. Next Steps
77. Next Steps
78. Next Steps
79. Next Steps
80. Objects Collaborations Business Rules Services Attributes
81. nicholas@firsthand.ca @nicholasjhenry Nicholas Henry http://bit.ly/motrsb