The Java driver for MongoDB has been around almost as long as the NoSQL database itself. It was designed without some of the modern Java features we now take for granted, and the API might be easier with features like lambdas. The existing Java driver is extensively used, which leads to a tricky question: how do you create a new API that uses modern development patterns whilst retaining backwards compatibility? Your users are fundamental to the success of your business, you do not want to alienate them, break their systems or make it hard for them to migrate to the New World Order. In this presentation Trisha will share some of the pain experienced and solutions tried while creating a new Java driver for MongoDB.

1. Trisha Gee
#GeeCON
Java Driver Developer, 10gen
@trisha_gee
What do you mean,
backwards compatibility?
Thursday, 16 May 13

2. Design: translate the
requirements in a
specification that describes
the global architecture and
the functionality of the
system.
http://homepages.cwi.nl/~paulk/patents/isnot/node4.html
Thursday, 16 May 13

3. Managing the Development of Large
Software Systems - Dr Winston Royce
http://www.cs.umd.edu/class/spring2003/cmsc838p/Process/waterfall.pdf
Thursday, 16 May 13

4. Agile Design
<This Page Left Intentionally Blank>
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5. Design is a Process, not
a Document
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6. What are you saying?
• Design is a journey, enjoy the ride
• There will be Monsters
• There will be Safe Houses
• There might not even be a destination...
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7. Best Job Evar!!
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8. We’re off!
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9. Backward Compatibility
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10. Lots of unknowns
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11. Design Goals
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12. Yes, it’s a document
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13. Design Goals
• Consistency
• Cleaner design
• Intuitive API
• Sane Exception handling
• Test friendly
• Backwards compatible
Thursday, 16 May 13

14. Lack of consistency
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15. Coding Standards
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16. Zero Analysis Errors
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17. No more arguments
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18. Design Goals
✓Consistency
• Cleaner design
• Intuitive API
• Sane Exception handling
• Test friendly
• Backwards compatible
Thursday, 16 May 13

19. Users
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20. Identify Our Users
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21. 1. Java Developers
2. ODMs / other drivers / third parties
3. Contributors
Three Types Of Users
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22. Java Developers
• Consistency
• Cleaner design
•Intuitive API
•Sane Exception handling
•Test friendly
•Backwards compatible
Thursday, 16 May 13

23. Third Party Libraries
•Consistency
•Cleaner design
• Intuitive API
• Sane Exception handling
•Test friendly
•Backwards compatible
Thursday, 16 May 13

24. Contributors
•Consistency
•Cleaner design
• Intuitive API
•Sane Exception handling
•Test friendly
• Backwards compatible
Thursday, 16 May 13

25. Users are our friends
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26. Backward Compatibility
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27. Architecture
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28. UML, yuk!
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29. High Level Architecture
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30. Scala Driver
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31. Design Goals
• Consistency
✓Cleaner design
• Intuitive API
• Sane Exception handling
• Test friendly
• Backwards compatible
Thursday, 16 May 13

32. Design Goals
• Consistency
• Cleaner design
• Intuitive API
• Sane Exception handling
• Test friendly
•Backwards compatible
Thursday, 16 May 13

33. High Level Architecture
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34. Option 1:Wrapping
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35. Option 2: Connecting
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36. Backward Compatibility?
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37. Tests Pass
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38. We win!
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39. Design Goals
• Consistency
• Cleaner design
• Intuitive API
• Sane Exception handling
• Test friendly
✓Backwards compatible
Thursday, 16 May 13

40. Not DeadYet...
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41. The Public API
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42. Design Goals
• Consistency
• Cleaner design
•Intuitive API
• Sane Exception handling
• Test friendly
• Backwards compatible
Thursday, 16 May 13

43. Caveats
• It won’t look like this
• Haven’t decided consistent names yet
• Need something that suits all drivers
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44. Find
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45. Find
collection.find(query).skip(1000).limit(100);
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46. Find
collection.find(query).skip(1000).limit(100);
collection.find(query).skip(1000).limit(100);
Thursday, 16 May 13

47. Find
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48. Find
collection.find(query).skip(1000).limit(100);
collection.find(query).skip(1000).limit(100);
collection.find(query, fields);
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49. Which One?
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50. Find
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51. Find
collection.find(query).skip(1000).limit(100);
collection.find(query).skip(1000).limit(100);
collection.find(query, fields);
Thursday, 16 May 13

52. Find
collection.find(query).skip(1000).limit(100);
collection.find(query).skip(1000).limit(100);
collection.find(query, fields);
collection.find(query).select(fields);
Thursday, 16 May 13

53. Fewer Decisions
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54. “Cmd + space” friendly
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55. Find
collection.find(query).skip(1000).limit(100);
collection.find(query).skip(1000).limit(100);
collection.find(query, fields);
collection.find(query).select(fields);
Thursday, 16 May 13

56. Remove
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57. Remove
collection.remove(query);
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58. Remove
collection.remove(query);
collection.find(query).remove();
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59. Find and Modify
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60. Find and Modify
collection.findAndModify(query, update);
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61. Find and Modify
collection.findAndModify(query, update);
collection.find(query).updateOneAndGet(update);
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62. They hate me!
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63. Find and Modify
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64. Find and Modify
collection.findAndModify(query, update);
collection.find(query)
.updateOneAndGet(update);
collection.findAndModify(query,
fields,
sort,
false,
update,
true,
false);
Thursday, 16 May 13

65. Find and Modify
collection.findAndModify(query, update);
collection.find(query)
.updateOneAndGet(update);
collection.findAndModify(query,
fields,
sort,
false,
update,
true,
false);
collection.find(query)
.sort(sort)
.updateOneAndGet(update);
Thursday, 16 May 13

66. Find and Modify
Thursday, 16 May 13

67. Find and Modify
collection.findAndModify(query, update);
collection.find(query)
.updateOneAndGet(update);
collection.findAndModify(query,
fields,
sort,
false,
update,
true,
false);
collection.find(query)
.sort(sort)
.updateOneAndGet(update);
Thursday, 16 May 13

68. Find and Modify
collection.findAndModify(query, update);
collection.find(query)
.updateOneAndGet(update);
collection.findAndModify(query,
fields,
sort,
false,
update,
true,
false);
collection.find(query)
.sort(sort)
.updateOneAndGet(update);
collection.find(query)
.sort(sort)
.getOneAndUpdate(update);
Thursday, 16 May 13

69. Lack of consistency
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70. Consistency at last
collection.find(query).limit(10);
collection.find(query).limit(10).remove();
collection.find(query).sort(sortCriteria).getOne();
collection.find(query).sort(sortCriteria).remove();
collection.find(query).sort(sortCriteria).count();
Thursday, 16 May 13

71. Muerto del todo
✓Consistency
• Cleaner design
• Intuitive API
• Sane Exception handling
• Test friendly
• Backwards compatible
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72. Design Goals
• Consistency
• Cleaner design
•Intuitive API...
• Sane Exception handling
• Test friendly
• Backwards compatible
Thursday, 16 May 13

73. Not DeadYet!
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74. Tutorial/hack session
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75. This talk
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76. Design is a Process, not
a Document
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77. Q & A
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78. 1.Are you using the Java
driver?
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79. 2. What do you like
about it?
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80. 3. What are your pain
points?
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81. Design is a Process, not
a Document
Thursday, 16 May 13

82. Your Questions
Thursday, 16 May 13