Domain-Driven Transformation

Transcript

1. Starring Directed By Special Appearance Presented by Photo: Hackercatxxy/Wikipedia
3. @hschwentner
4. @hschwentner
5. @hschwentner
6. @hschwentner
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9. @hschwentner
12. THE NAME OF THIS SPEAKER IS HENNING SCHWENTNER LIVE 45 MIN TALK
13. !"# Kolleg:in gesucht (Deutschlandweit)
16. Story Time
17. @hschwentner Alphorn Auto Leasing Inc.
18. @hschwentner
19. @hschwentner
20. Monolease A
21. salesperson [person] Monolease [software system] Central car leasing tool customer [external person] risk manager [person] closes leasing contracts with creates and calculates contracts in assesses risk of contracts in Alphorn Auto Leasing Inc. [enterprise] Context
22. @hschwentner Photo: Myriam Thyes/Wikipedia
23. @hschwentner Photo: Keiichi Inoue/flickr
24. @hschwentner long time to market error-prone teams get in each other’s way Issues with Legacy Systems it’s hard to build new ideas into the system and they are doing more or less the same there are often more than one
25. @hschwentner Alphorn’s boss: “Modernize it!”
26. @hschwentner Photo: Keiichi Inoue/flickr
27. => I hate this old mess! This system has earned our money for decades
28. @hschwentner The consultant: “Modularize it!”
29. => modules monolith to
30. => modules monolith buy to carve out build new
31. @hschwentner Diagnosis: From Which Diseases Does Our Patient suffer?
32. @hschwentner Different diseases require different treatment
33. @hschwentner big ball of mud poorly expressed domain knowledge bad team organization Typical Diseases of Legacy Systems
34. @hschwentner big ball of mud poorly expressed domain knowledge bad team organization Cures strategic transformation tactical transformation team-organizational transformation
35. @hschwentner Domain-Driven Refactorings • Strategic Refactorings • Tactical Refactorings (that support strategic ones) Catalog: https://hschwentner.io/domain-driven-refactorings strategic transformation tactical transformation team-organizational transformation • Socio-Technical • Tactical refactorings (that strengthen domain knowledge in the code)
36. @hschwentner Strategic
37. @hschwentner Strategic Transformation 1. Step: Domain re-discovery 2. Step: Modeling the target architecture 3. Step: Aligning current with target architecture 4. Step: Do the move
38. @hschwentner Strategic Transformation 1. Step: Domain re-discovery 2. Step: Modeling the target architecture 3. Step: Aligning current with target architecture 4. Step: Do the move
39. @hschwentner Step 1: Domain Re-Discovery
40. @hschwentner To modernize the legacy system we first have to put it aside
41. @hschwentner To split the monolith we first have to put it aside
42. Mindset Switch
43. thinking about business => thinking about technology to
44. ! ! " have to understand To build software: Tech people business people. # "
45. ! ! " # " Tech people business people. common understanding
46. ! ! " # " Tech people business people. common language
47. ! ! " # " Tech people business people. ubiquitous language
48. => direct commu- nication telephone game to user dev user dev
49. Collaborative Modeling
50. Collaborative Modeling
51. customer tells wish for 1 salesperson signs to gives for contract 3 risk manager contract passes on to 4 contract votes checks calculates 5 6 7 calculates to 8 2 car credit rating installment car resale value contract
52. https://hschwentner.io Read on in:
53. May 7th—10th 2025 Vienna, Austria The Collaborative Modeling Unconference comocamp.org Event Storming User Story Mapping Event Modeling Impact Mapping Domain Storytelling Storystorming Context Mapping Example Mapping etc.
54. @hschwentner Step 2: Determining the Target Architecture
55. Drawing Boundaries
56. Which activities belong together (from an actor’s perspective)?
57. customer tells wish for 1 salesperson signs to gives for contract 3 risk manager contract passes on to 4 contract votes checks calculates 5 6 7 calculates to 8 2 car credit rating installment car resale value contract sales risk assessment
58. @hschwentner sales risk assessment Context Map
59. @hschwentner Step 3: Aligning Current Architecture with Target Architeture
60. @hschwentner Aligning Current and Target Architecture current target
61. @hschwentner Determining the Current Architecture analysis tool developers architecture analyst source code
62. https://sustainable-software- architecture.com Read on in: analysis tool architecture analyst
63. Monolease [software system] salesperson [person] Monolease [software system] Central car leasing tool customer [external person] risk manager [person] closes leasing contracts with creates and calculates contracts in assesses risk of contracts in Alphorn Auto Leasing Inc. [enterprise] Context again
64. backend [container] database [container] frontend [container] salesperson [person] backend [container: EJB 2] risk manager [person] creates and calculates contracts in assesses risk of contracts in Monolease [software system] frontend [container: servlets, JSPs] database [container: IBM DB2] Containers
65. Calculator [component] frontend [container] LeasingServlet [component: servlet] CONTRACTS [database table] PartnerServlet [component: servlet] ContractService [component] PartnerService [component] backend [container] database [container] Contract [component] Partner [component] PARTNERS [database table] Components
66. big ball of mud => no vertical structuring
67. @hschwentner Aligning Current and Target Architecture current target
68. Calculator [component] frontend [container] LeasingServlet [component: servlet] CONTRACTS [database table] PartnerServlet [component: servlet] ContractService [component] PartnerService [component] backend [container] database [container] Contract [component] Partner [component] PARTNERS [database table] Components
69. Calculator [component] ContractService [component] PartnerService [component] backend [container] Contract [component] Partner [component] Component Backend
70. Component Bounded Contexts Sales Risk assessment
71. Calculator [component] ContractService [component] PartnerService [component] Contract [component] Partner [component] Component Bounded Contexts Sales Risk Assessment
72. Calculator [component] ContractService [component] PartnerService [component] Contract [component] Partner [component] Sales Risk Assessment Contract [component] Partner [component] Duplication?
73. @hschwentner Dave Thomas The DRY Principle Andy Hunt “Every piece of knowledge must have a single, unambiguous, authoritative representation within a system.”
74. ContractService [component] Contract [component] Component Backend Sales Risk assessment
75. ContractService signContract() voteContract() Code Contract getContractNumber() setSignatureDate() setCreditRating() setVotingResult()
76. customer tells wish for 1 salesperson signs to gives for contract 3 risk manager contract passes on to 4 contract votes checks calculates 5 6 7 calculates to 8 2 car credit rating installment car resale value contract sales risk assessment
77. ContractService signContract() voteContract() Code Contract getContractNumber() setSignatureDate() setCreditRating() setVotingResult() Sales Risk Assessment
78. ContractService signContract() voteContract() Code Contract getContractNumber() setSignatureDate() setCreditRating() setVotingResult() Sales Risk Assessment ContractService signContract() voteContract() Contract getContractNumber() setSignatureDate() setCreditRating() setVotingResult()
79. ContractService signContract() Code Contract getContractNumber() setSignatureDate() Sales Risk Assessment ContractService voteContract() Contract getContractNumber() setCreditRating() setVotingResult()
80. ContractService signContract() Code Contract getContractNumber() setSignatureDate() Sales Risk Assessment ContractService voteContract() Contract getContractNumber() setCreditRating() setVotingResult()
81. ContractService signContract() Contract getContractNumber() setSignatureDate() Sales Risk Assessment ContractService voteContract() Contract getContractNumber() setCreditRating() setVotingResult() ContractService signContract() voteContract() Contract getContractNumber() setSignatureDate() setCreditRating() setVotingResult() Monolease =>
82. @hschwentner Improvement Backlog 1.2 Extract Specialized “Contract Service” 1.1 Extract Specialized “Contract” 1 Extract Context “Sales” Collecting Refactorings 2 Extract Context “Risk assessment” 2.1 Extract Specialized “Contract Service” 2.1 Extract Specialized “Contract”
83. @hschwentner Step 4: Do the Move
84. @hschwentner Improvement Backlog Planning Transformation Tactical Refactoring 1.1 Strategic Refactoring 1 User Story A Product Backlog User Story E User Story B User Story C User Story D Tactical Refactoring 1.2 Tactical Refactoring 1.3 Tactical Refactoring 2.1 Strategic Refactoring 2 Sprint Backlog
85. @hschwentner Improvement Backlog Planning Transformation User Story A Product Backlog User Story E User Story B User Story C User Story D Sprint Backlog Tactical Refactoring 1.1 Strategic Refactoring 1 Tactical Refactoring 1.2 Tactical Refactoring 1.3 Tactical Refactoring 2.1 Strategic Refactoring 2
86. @hschwentner Improvement Backlog Planning Transformation Tactical Refactoring 1.1 Strategic Refactoring 1 User Story A Product Backlog User Story E User Story B User Story C User Story D Tactical Refactoring 1.2 Tactical Refactoring 1.3 Tactical Refactoring 2.1 Strategic Refactoring 2 Sprint Backlog
87. @hschwentner Improvement Backlog Planning Transformation Strategic Refactoring 1 Product Backlog User Story E User Story C User Story D Tactical Refactoring 1.3 Tactical Refactoring 2.1 Strategic Refactoring 2 Sprint Backlog
88. @hschwentner Improvement Backlog Planning Transformation Strategic Refactoring 1 Product Backlog User Story E User Story C User Story D Tactical Refactoring 2.1 Strategic Refactoring 2 Sprint Backlog User Story F User Story G Tactical Refactoring 1.3
89. @hschwentner Improvement Backlog Planning Transformation Strategic Refactoring 1 Product Backlog User Story E User Story C User Story D Tactical Refactoring 1.3 Tactical Refactoring 2.1 Strategic Refactoring 2 Sprint Backlog User Story F User Story G
90. @hschwentner Improvement Backlog Planning Transformation Product Backlog User Story E Tactical Refactoring 2.1 Strategic Refactoring 2 Sprint Backlog User Story F User Story G
91. @hschwentner Improvement Backlog Planning Transformation Product Backlog User Story E Tactical Refactoring 2.1 Strategic Refactoring 2 Sprint Backlog User Story G User Story H User Story F User Story I
92. ContractService signContract() voteContract() Code Contract getContractNumber() setSignatureDate() setCreditRating() setVotingResult() Risk Assessment ContractService Contract Monolease voteContract() getContractNumber() setCreditRating() setVotingResult()
93. ContractService signContract() Code Contract getContractNumber() setSignatureDate() Risk Assessment ContractService Contract Monolease voteContract() getContractNumber() setCreditRating() setVotingResult()
94. @hschwentner Tactical
95. Code Risk Assessment ContractService voteContract() Contract getContractNumber() setCreditRating() setVotingResult() anemic
97. @hschwentner Team- Organizational
98. @hschwentner sales risk assessment A Context Belongs to a Team Exclusively team A team B
99. @hschwentner Outlook
100. @hschwentner What Else? Socio-technical transformation Technical transformation Tactical transformation Anti-Anemia refactorings
101. @hschwentner Domain Patterns Pipeline Domain Blackboard Domain Dialog Domain • Logistics • Insurances and banks • administration • healthcare • event management • control center • Software development • Communication software • Negotiations in various domains
102. @hschwentner Conclusion
104. https://hschwentner.io Read on in: https://hschwentner.io/domain-driven-refactorings
105. Lesson: is possible Monolith transformation (and hard) =>
106. @hschwentner Mistake: Going on the journey alone Better:
107. Photo: Henning Schwentner
108. ! ❤
109. @hschwentner
110. Bibliography Conway, Melvin E. “How Do Committees Invent?” Datamation 14, no. 5 (April 1968): 28–31. Evans, Eric. Domain-Driven Design: Tackling Complexity in the Heart of Software. Boston: Addison- Wesley, 2004. Feathers, Michael C. Working Effectively with Legacy Code. Upper Saddle River, NJ: Prentice Hall, 2004. Foote, Brian and Joseph Yoder. “Big Ball of Mud.” PLoP ’97, Monticello, IL, September 1997. Fowler, Martin. “Strangler Fig Application.” Bliki, June 29, 2004. Fowler, Martin. Refactoring: Improving the Design of Existing Code. 2nd ed. Boston: Addison-Wesley, 2019. Hofer, Stefan and Henning Schwentner. Domain Storytelling: a Collaborative, Visual, and Agile Way to Develop Domain-Driven Software. Boston: Addison-Wesley, 2022. Lilienthal, Carola. Sustainable Software Architecture: Analyze and Reduce Technical Dept. Heidelberg: dpunkt, 2019. Lilienthal, Carola and Henning Schwentner. Domain-Driven Transformation: Modularize and Modernize Legacy Software. Boston: Addison-Wesley, 2025. Kernighan, Brian W. Software Tools in Pascal. Addison-Wesley, 1981. Newman, Sam. Monolith to Microservices: Evolutionary Patterns to Transform Your Monolith.
112. Henning Schwentner  https://hschwentner.io  in/henningschwentner ✉ hs@wps.de Kolleg:in gesucht (Deutschlandweit)