Code Generating Your Way to Happiness

This talk explores how code gen can be used to eliminate a class of issues and sources of developer boilerplate, as well as walking through some popular libraries and uber-specific use cases.

Transcript

1. Code generating your way to happiness Zac Sweers - Uber @pandanomic
2. "Code generating your way to happiness."
3. FileSpec.builder("", "Presentation") .addComment("Code generating your way to happiness.") .addAnnotation(AnnotationSpec.builder(Author::class) .addMember("name", "%S", "Zac Sweers") .useSiteTarget(FILE) .build()) .build()
4. FileSpec.builder("", "Presentation") .addComment("Code generating your way to happiness.") .addAnnotation(AnnotationSpec.builder(Author::class) .addMember("name", "%S", "Zac Sweers") .useSiteTarget(FILE) .build()) .build()
5. FileSpec.builder("", "Presentation") .addComment("Code generating your way to happiness.") .addAnnotation(AnnotationSpec.builder(Author::class) .addMember("name", "%S", "Zac Sweers") .useSiteTarget(FILE) .build()) .build()
6. FileSpec.builder("", "Presentation") .addComment("Code generating your way to happiness.") .addAnnotation(AnnotationSpec.builder(Author::class) .addMember("name", "%S", "Zac Sweers") .useSiteTarget(FILE) .build()) .build()
7. FileSpec.builder("", "Presentation") .addComment("Code generating your way to happiness.") .addAnnotation(AnnotationSpec.builder(Author::class) .addMember("name", "%S", "Zac Sweers") .useSiteTarget(FILE) .build()) .build()
8. FileSpec.builder("", "Presentation") .addComment("Code generating your way to happiness.") .addAnnotation(AnnotationSpec.builder(Author::class) .addMember("name", "%S", "Zac Sweers") .useSiteTarget(FILE) .build()) .build()
9. // Code generating your way to happiness. @file:Author(name = "Zac Sweers") Presentation.kt
10. FileSpec.builder("", "Presentation")a .addComment("Code generating your way to happiness.") .addAnnotation(AnnotationSpec.builder(Author::class) .addMember("name", "%S", "Zac Sweers") .useSiteTarget(FILE) .build()) .build()b
11. FileSpec.builder("", presentationName)a .addComment("Code generating your way to happiness.") .addAnnotation(AnnotationSpec.builder(Author::class) .addMember("name", "%S", "Zac Sweers") .useSiteTarget(FILE) .build()) .build()b
12. FileSpec.builder("", presentationName)a .addComment(comment) .addAnnotation(AnnotationSpec.builder(Author::class) .addMember("name", "%S", "Zac Sweers") .useSiteTarget(FILE) .build()) .build()b
13. FileSpec.builder("", presentationName)a .addComment(comment) .addAnnotation(AnnotationSpec.builder(Author::class) .addMember("name", "%S", author) .useSiteTarget(FILE) .build()) .build()b
14. presentations.onEach { (presentationName, comment, author) -> FileSpec.builder("", presentationName)a .addComment(comment) .addAnnotation(AnnotationSpec.builder(Author::class) .addMember("name", "%S", author) .useSiteTarget(FILE) .build()) .build()b }
15. conferences .flatMap { it.presentations } .onEach { (presentationName, comment, author) -> FileSpec.builder("", presentationName)a .addComment(comment) .addAnnotation(AnnotationSpec.builder(Author::class) .addMember("name", "%S", author) .useSiteTarget(FILE) .build()) .build()b } Boilerplate
16. Benefits • Boilerplate avoidance
17. Benefits • Boilerplate avoidance • Correctness
18. Correctness class Person(val firstName: String, val lastName: String)m
19. class Person(val firstName: String, val lastName: String)m class PersonJsonAdapter : JsonAdapter<Person>() {a }l
20. class Person(val firstName: String, val lastName: String)m class PersonJsonAdapter : JsonAdapter<Person>() {a override fun fromJson(reader: JsonReader): Person? {b }k }l
21. class Person(val firstName: String, val lastName: String)m class PersonJsonAdapter : JsonAdapter<Person>() {a override fun fromJson(reader: JsonReader): Person? {b lateinit var firstName: Stringc lateinit var lastName: Stringd }k }l
22. class Person(val firstName: String, val lastName: String)m class PersonJsonAdapter : JsonAdapter<Person>() {a override fun fromJson(reader: JsonReader): Person? {b lateinit var firstName: Stringc lateinit var lastName: Stringd return Person(firstName, lastName)j }k }l
23. class Person(val firstName: String, val lastName: String)m class PersonJsonAdapter : JsonAdapter<Person>() {a override fun fromJson(reader: JsonReader): Person? {b lateinit var firstName: Stringc lateinit var lastName: Stringd while (reader.hasNext()) {e }n return Person(firstName, lastName)j }k }l
24. class Person(val firstName: String, val lastName: String)m class PersonJsonAdapter : JsonAdapter<Person>() {a override fun fromJson(reader: JsonReader): Person? {b lateinit var firstName: Stringc lateinit var lastName: Stringd while (reader.hasNext()) {e when (reader.nextName()) {f }o }n return Person(firstName, lastName)j }k }l
25. class Person(val firstName: String, val lastName: String)m class PersonJsonAdapter : JsonAdapter<Person>() {a override fun fromJson(reader: JsonReader): Person? {b lateinit var firstName: Stringc lateinit var lastName: Stringd while (reader.hasNext()) {e when (reader.nextName()) {f "firstName" -> firstName = reader.nextString()g }o }n return Person(firstName, lastName)j }k }l
26. class Person(val firstName: String, val lastName: String)m class PersonJsonAdapter : JsonAdapter<Person>() {a override fun fromJson(reader: JsonReader): Person? {b lateinit var firstName: Stringc lateinit var lastName: Stringd while (reader.hasNext()) {e when (reader.nextName()) {f "firstName" -> firstName = reader.nextString()g "lastName" -> lastName = reader.nextString()h }o }n return Person(firstName, lastName)j }k }l
27. class Person(val firstName: String, val lastName: String)m class PersonJsonAdapter : JsonAdapter<Person>() {a override fun fromJson(reader: JsonReader): Person? {b lateinit var firstName: Stringc lateinit var lastName: Stringd while (reader.hasNext()) {e when (reader.nextName()) {f "firstName" -> firstName = reader.nextString()g "lastName" -> lastName = reader.nextString()h else -> reader.skipValue()i }o }n return Person(firstName, lastName)j }k }l
28. class Person(val firstName: String, val lastName: String)m class PersonJsonAdapter : JsonAdapter<Person>() {a override fun fromJson(reader: JsonReader): Person? {b lateinit var firstName: Stringc lateinit var lastName: Stringd while (reader.hasNext()) {e when (reader.nextName()) {f "firstname" -> firstName = reader.nextString()g "lastName" -> lastName = reader.nextString()h else -> reader.skipValue()i }o }n return Person(firstName, lastName)j }k }l
29. class Person(val firstName: String, val lastName: String)m class PersonJsonAdapter : JsonAdapter<Person>() {a override fun fromJson(reader: JsonReader): Person? {b lateinit var firstName: Stringc lateinit var lastName: Stringd while (reader.hasNext()) {e when (reader.nextName()) {f "firstname" -> firstName = reader.nextString()g "lastName" -> lastName = reader.nextString()h else -> reader.skipValue()i }o }n return Person(lastName, firstName)j }k }l
30. class Person(val firstName: String?, val lastName: String)m class PersonJsonAdapter : JsonAdapter<Person>() {a override fun fromJson(reader: JsonReader): Person? {b lateinit var firstName: Stringc lateinit var lastName: Stringd while (reader.hasNext()) {e when (reader.nextName()) {f "firstname" -> firstName = reader.nextString()g "lastName" -> lastName = reader.nextString()h else -> reader.skipValue()i }o }n return Person(lastName, firstName)j }k }l
31. class Person(val firstName: String, val lastName: String)m
32. class Person(val firstName: String, val lastName: String)m class City(val name: String, val country: String) class Vehicle(val licensePlate: String) class Restaurant(val type: String, val address: Address) class Payment(val cardNumber: String, val type: String) class TipAmount(val value: Double) class Rating(val numStars: Int) class Correctness(val confidence: Double)
33. Benefits • Boilerplate • Correctness
34. Recognizing • Boilerplate • Correctness Boilerplate Ceremony Value types! Especially if you have specs! Tests too
35. Tools
36. Tools •JavaPoet/KotlinPoet
37. Tools •JavaPoet/KotlinPoet •Templating
38. Tools •JavaPoet/KotlinPoet •Templating •SPI
39. Tools •JavaPoet/KotlinPoet •Templating •SPI •Compile Testing
40. Tools •JavaPoet/KotlinPoet •Templating •SPI •Compile Testing •Annotation Processing (APT)
41. Tools •JavaPoet/KotlinPoet •Templating •SPI •Compile Testing •Annotation Processing (APT) •Gradle
42. Examples
43. Butter Knife
44. Butter Knife TextView title;a void onCreate(Bundle savedInstanceState) {c title = findViewById(R.id.title);d }f
45. Butter Knife TextView title;a ImageView icon;b void onCreate(Bundle savedInstanceState) {c title = findViewById(R.id.title);d }f
46. Butter Knife TextView title;a ImageView icon;b void onCreate(Bundle savedInstanceState) {c title = findViewById(R.id.title);d icon = findViewById(R.id.icon);e }f
47. Butter Knife @BindView(R.id.title) TextView title;a @BindView(R.id.icon) ImageView icon;b void onCreate(Bundle savedInstanceState) {c ButterKnife.bind(this); }f
48. Butter Knife @BindView(R.id.title) TextView title;a @BindView(R.id.icon) ImageView icon;b @BindView(R.id.button) Button button; void onCreate(Bundle savedInstanceState) {c ButterKnife.bind(this);g }f
49. Butter Knife @BindView(R.id.title) TextView title;a void onCreate(Bundle savedInstanceState) {c ButterKnife.bind(this); }f
50. @BindView(R.id.title) TextView title;
51. // FooActivity @BindView(R.id.title) TextView title;
52. // FooActivity @BindView(R.id.title) TextView title;
53. // FooActivity @BindView(R.id.title) TextView title;
54. // FooActivity @BindView(2131361859) TextView title;
55. // FooActivity @BindView(2131361859) TextView title;
56. // FooActivity @BindView(2131361859) TextView title;
57. // FooActivity @BindView(2131361859) TextView title;
58. ViewBinding( target = "FooActivity", id = 2131361859, name = "title", type = "field", viewType = TextView.class )
59. public final class FooActivity_ViewBinding implements Unbinder { private FooActivity target; @UiThread public FooActivity_ViewBinding(FooActivity target, View source) { this.target = target; target.title = Utils.findRequiredViewAsType(source, 2131361859, // R.id.title "field 'title'", TextView.class); }a }b
60. @BindView(R.id.title) TextView title;a void onCreate(Bundle savedInstanceState) {c ButterKnife.bind(this); }f public final class FooActivity_ViewBinding implements Unbinder { private FooActivity target; @UiThread public FooActivity_ViewBinding(FooActivity target, View source) { this.target = target; target.title = Utils.findRequiredViewAsType(source, 2131361859, // R.id.title "field 'title'", TextView.class); }a }b APT Runtime
61. Butter Knife
62. RxBinding
63. RxBinding KotlinGenTask Generates all these!
64. public static Observable<Object> clicks(View view) { return new ViewClickObservable(view); }
65. fun View.clicks(): Observable<Object> = RxView.clicks(this)a
66. fun View.clicks(): Observable<Unit> = RxView.clicks(this)a
67. fun View.clicks(): Observable<Unit> = RxView.clicks(this)a public static Observable<Object> clicks(View view) { return new ViewClickObservable(view); }b
68. fun View.clicks(): Observable<Unit> = RxView.clicks(this)a public static Observable<Object> clicks(View view) { return new ViewClickObservable(view); }b
69. fun View.clicks(): Observable<Unit> = RxView.clicks(this)a public static Observable<Object> clicks(View view) { return new ViewClickObservable(view); }b
70. fun View.clicks(): Observable<Unit> = RxView.clicks(this)a public static Observable<Object> clicks(View view) { return new ViewClickObservable(view); }b
71. fun View.clicks(): Observable<Unit> = RxView.clicks(this)a public static Observable<Object> clicks(View view) { return new ViewClickObservable(view); }b
72. fun View.clicks(): Observable<Unit> = RxView.clicks(this)a public static Observable<Object> clicks(View view) {a return new ViewClickObservable(view); }b
73. public static Observable<Object> clicks(View view) {a return new ViewClickObservable(view); }b
74. // RxView public static Observable<Object> clicks(View view) {a return new ViewClickObservable(view); }b
75. BindingMethod( target = "RxView", name = "clicks", type = View.class, returnType = "Observable<Object>" )b
76. BindingMethod( target = "RxView", name = "clicks", type = View.class, returnType = "Observable<Unit>" )b
77. fun View.clicks(): Observable<Unit> = RxView.clicks(this)a
78. RxBinding
79. Service Gen
80. @AutoValuea abstract class Rider {b abstract String uuid();c abstract String firstName();d abstract String lastName();e abstract Address address();f }g Service Gen
81. interface UberService {a @GET("/rider")b Rider getRider()c }d
82. interface UberService {a @GET("/rider")b Single<Rider> getRider()c }d
83. struct Rider { 1: required string uuid; 2: required string firstName; 3: required string lastName; 4: optional Address address; }
84. @AutoValuea abstract class Rider {b abstract String uuid();c abstract String firstName();d abstract String lastName();e abstract Address address();f }g
85. @AutoValuea abstract class Rider {b abstract String uuid();c abstract String firstName();d abstract String lastName();e abstract Address address();f static JsonAdapter<Rider> jsonAdapter(Moshi moshi) { return new AutoValue_Rider.JsonAdapter(moshi); } }g
86. service UberService {a Rider getRider() }b
87. service UberService {a Rider getRider() (path="/rider") }b
88. interface UberService { @GET("/rider") Single<Rider> getRider() }
89. service UberService { Rider getRider() }
90. astruct Rider
91. astruct Rider struct City struct Vehicle struct Restaurant struct Payment struct TipAmount struct Rating
92. astruct Rider struct City struct Vehicle struct Restaurant struct Payment struct TipAmount struct Rating // And 6000 more
93. class ModelsAdapterFactory implements JsonAdapter.Factory { @Override public JsonAdapter<?> create(Type type, Set<? extends Annotation> annotations, Moshi moshi) { Class<?> rawType = Types.getRawType(type); if (rawType.isAssignableFrom(Rider.class)) { return Rider.adapter(moshi); } else if (rawType.isAssignableFrom(City.class)) { return City.adapter(moshi); } else if (rawType.isAssignableFrom(Vehicle.class)) { return Vehicle.adapter(moshi); } // Etc etc return null; } }
94. astruct Rider struct City struct Vehicle struct Restaurant struct Payment struct TipAmount struct Rating //aAnd 6000 more
95. //aAnd 6000 more
96. //aAnd 6000 more Rider EATS Payments Driver GiftCard Pricing
97. Rider GiftCard Pricing Driver EATS Payments
98. Rider - build.gradle GiftCard - build.gradle Pricing - build.gradle Driver - build.gradle EATS - build.gradle Payments - build.gradle
99. Rider - build.gradle GiftCard - build.gradle Pricing - build.gradle Driver - build.gradle EATS - build.gradle Payments - build.gradle
100. Rider GiftCard Pricing Driver EATS Payments
101. xclass RiderModelFactory class GiftCardModelFactory class PricingModelFactory class DriverModelFactory class EATSModelFactory class PaymentsModelFactory
102. xclass RiderModelFactory
103. xclass RiderModelFactory // -> json
104. xclass RiderModelFactory // -> json // -> ridermodelfactory-fractory.binx
105. class RiderModelFactory // -> json // -> ridermodelfactory-fractory.bin class MyAppGlobalFactory // Delegates to all discovered fractories
106. class RiderModelFactory // -> json // -> ridermodelfactory-fractory.bin class MyAppGlobalFactory // Delegates to all discovered fractories Fractory C om ing Soon™
107. .thrift Thrifty "Jenga" .java APT AutoValueProcessor auto-value-moshi fractory Pre-build Compilation *SPI* Project Gen *Gradle* *Templating* *JavaPoet*
108. Tools •JavaPoet •KotlinPoet •Templating •SPI •Compile Testing •Annotation Processing (APT) •Gradle
109. Pitfalls
110. BLOAT
111. Rider app a
112. Rider app a b 10% Dagger
113. Rider app a b 10% Dagger c 25% Models
114. struct Rider { 1: required string uuid; 2: required string firstName; 3: required string lastName; 4: optional Address address; }a
115. struct Rider { 1: required string uuid; 2: required string firstName; 3: required string lastName; 4: optional Address address; }a
116. struct Rider { 1: required string uuid; 2: required string firstName; 3: required string lastName; }a
117. struct Rider { 1: required string uuid; 2: required string firstName; 3: required string lastName; }a service UberService {a Rider getRider() }b
118. struct Rider { 1: required string uuid; 2: required string firstName; 3: required string lastName; }a service UberService {a Rider getRider() }b
119. struct Rider { 1: required string uuid; 2: required string firstName; 3: required string lastName; }a service UberService {a Rider getRider() }b
120. Rider app a b c
121. Rider app a b c $$
122. Fin Zac Sweers - Uber @pandanomic