Slide 1

Slide 1 text

Kotlin Code Generation Alec Strong & Jake Wharton

Slide 2

Slide 2 text

public final class User { private final String firstName; private final String lastName; private final int age; public User(String firstName, String lastName, int age) { this.firstName = firstName; this.lastName = lastName; this.age = age; } public String getFirstName() { return firstName; } public String getLastName() { return lastName; } public int getAge() { return age; } @Override public boolean equals(Object o) { if (this == o) return true; if (o == null || getClass() != o.getClass()) return false; User user = (User) o; return age == user.age && Objects.equals(firstName, user.firstName) && Objects.equals(lastName, user.lastName); } @Override public int hashCode() { return Objects.hash(firstName, lastName, age); } @Override public String toString() { return "User{" + "firstName='" + firstName + '\'' + ", lastName='" + lastName + '\'' + ", age=" + age + '}'; } } data class User( val firstName: String, val lastName: String, val age: Int )

Slide 3

Slide 3 text

Bytecode

Slide 4

Slide 4 text

Protocol Buffers

Slide 5

Slide 5 text

Protocol Buffers SQL

Slide 6

Slide 6 text

Protocol Buffers SQL Swagger

Slide 7

Slide 7 text

Protocol Buffers SQL Swagger Android XML

Slide 8

Slide 8 text

Protocol Buffers SQL Swagger Android XML YAML

Slide 9

Slide 9 text

SQL Swagger Android XML YAML Mirrors/Elements

Slide 10

Slide 10 text

Swagger Android XML YAML Mirrors/Elements PSI

Slide 11

Slide 11 text

Android XML YAML Mirrors/Elements PSI UAST

Slide 12

Slide 12 text

YAML Mirrors/Elements PSI UAST ???

Slide 13

Slide 13 text

Protocol Buffers SQL Swagger Android XML YAML Mirrors/Elements PSI UAST ???

Slide 14

Slide 14 text

Protocol Buffers

Slide 15

Slide 15 text

syntax = "proto2"; package com.sample; message Ogre { required string name = 1; repeated int32 layers = 2; optional string swamp = 3; }

Slide 16

Slide 16 text

public final String name; public final List layers; public final String swamp; public Ogre(String name, List layers, String swamp) { this(name, layers, swamp, ByteString.EMPTY); } public Ogre(String name, List layers, String swamp, ByteString unknownFields) { super(ADAPTER, unknownFields); this.name = name; this.layers = Internal.immutableCopyOf("layers", layers); this.swamp = swamp; }

Slide 17

Slide 17 text

public final String name; public final List layers; public final String swamp; public Ogre(String name, List layers, String swamp) { this(name, layers, swamp, ByteString.EMPTY); } public Ogre(String name, List layers, String swamp, ByteString unknownFields) { super(ADAPTER, unknownFields); this.name = name; this.layers = Internal.immutableCopyOf("layers", layers); this.swamp = swamp; } public final String name; public final List layers; public final String swamp; this.name = name; this.layers = Internal.immutableCopyOf("layers", layers); this.swamp = swamp;

Slide 18

Slide 18 text

public final String name; public final List layers; public final String swamp; public Ogre(String name, List layers, String swamp) { this(name, layers, swamp, ByteString.EMPTY); } public Ogre(String name, List layers, String swamp, ByteString unknownFields) { super(ADAPTER, unknownFields); this.name = name; this.layers = Internal.immutableCopyOf("layers", layers); this.swamp = swamp; } ByteString.EMPTY ByteString unknownFields

Slide 19

Slide 19 text

public final String name; public final List layers; public final String swamp; public Ogre(String name, List layers, String swamp) { this(name, layers, swamp, ByteString.EMPTY); } public Ogre(String name, List layers, String swamp, ByteString unknownFields) { super(ADAPTER, unknownFields); this.name = name; this.layers = Internal.immutableCopyOf("layers", layers); this.swamp = swamp; } Internal.immutableCopyOf("layers", layers)

Slide 20

Slide 20 text

public final String name; public final List layers; public final String swamp; public Ogre(String name, List layers, String swamp) { this(name, layers, swamp, ByteString.EMPTY); } public Ogre(String name, List layers, String swamp, ByteString unknownFields) { super(ADAPTER, unknownFields); this.name = name; this.layers = Internal.immutableCopyOf("layers", layers); this.swamp = swamp; } String name String swamp String name String swamp String name String swamp

Slide 21

Slide 21 text

public final String name; public final List layers; public final String swamp; public Ogre(String name, List layers, String swamp) { this(name, layers, swamp, ByteString.EMPTY); } public Ogre(String name, List layers, String swamp, ByteString unknownFields) { super(ADAPTER, unknownFields); this.name = name; this.layers = Internal.immutableCopyOf("layers", layers); this.swamp = swamp; }

Slide 22

Slide 22 text

class Ogre @JvmOverloads constructor( val name: String, val layers: List, val swamp: String?, unknownFields: ByteString = ByteString.EMPTY ) : Message(ADAPTER, unknownFields)

Slide 23

Slide 23 text

class Ogre @JvmOverloads constructor( val name: String, val layers: List, val swamp: String?, unknownFields: ByteString = ByteString.EMPTY ) : Message(ADAPTER, unknownFields) val name: String, val layers: List, val swamp: String?, Ogre shrek = new Ogre("Shrek", Arrays.asList(1, 2), null); System.out.println(shrek.getSwamp()); s

Slide 24

Slide 24 text

class Ogre @JvmOverloads constructor( @JvmField val name: String, @JvmField val layers: List, @JvmField val swamp: String?, unknownFields: ByteString = ByteString.EMPTY ) : Message(ADAPTER, unknownFields) @JvmField val name: String, @JvmField val layers: List, @JvmField val swamp: String?, Ogre shrek = new Ogre("Shrek", Arrays.asList(1, 2), null); System.out.println(shrek.swamp); Se

Slide 25

Slide 25 text

override fun equals(other: Any?): Boolean { if (other === this) return true if (other !is OgreKt) return false val o = other as OgreKt? return (unknownFields() == o!!.unknownFields() && name == o.name && layers == o.layers && Internal.equals(swamp, o.swamp)) } override fun hashCode(): Int { var result = super.hashCode if (result == 0) { result = unknownFields().hashCode() result = result * 37 + name.hashCode() result = result * 37 + layers.hashCode() result = result * 37 + (swamp?.hashCode() ?: 0) super.hashCode = result } return result } override fun toString(): String { val builder = StringBuilder() builder.append(", name=").append(name) if (!layers.isEmpty()) builder.append(", layers=").append(layers) if (swamp != null) builder.append(", swamp=").append(swamp) return builder.replace(0, 2, "Ogre{").append('}').toString() }

Slide 26

Slide 26 text

class Ogre @JvmOverloads constructor( @JvmField val name: String, @JvmField val layers: List, @JvmField val swamp: String?, unknownFields: ByteString = ByteString.EMPTY ) : Message(ADAPTER, unknownFields)

Slide 27

Slide 27 text

data class Ogre @JvmOverloads constructor( @JvmField val name: String, @JvmField val layers: List, @JvmField val swamp: String?, unknownFields: ByteString = ByteString.EMPTY ) : Message(ADAPTER, unknownFields)

Slide 28

Slide 28 text

data class Ogre @JvmOverloads constructor( @JvmField val name: String, @JvmField val layers: List, @JvmField val swamp: String?, unknownFields: ByteString = ByteString.EMPTY ) : Message(ADAPTER, unknownFields) data class Ogre unknownFields: ByteString = ByteString.EMPTY

Slide 29

Slide 29 text

data class Ogre @JvmOverloads constructor( @JvmField val name: String, @JvmField val layers: List, @JvmField val swamp: String?, private val unknownFields: ByteString = ByteString.EMPTY ) : Message(ADAPTER, unknownFields) data class Ogre private val unknownFields: ByteString = ByteString.EMPTY

Slide 30

Slide 30 text

class Ogre @JvmOverloads constructor( @JvmField val name: String, @JvmField val layers: List, @JvmField val swamp: String?, unknownFields: ByteString = ByteString.EMPTY ) : Message(ADAPTER, unknownFields)

Slide 31

Slide 31 text

public static final class Builder extends Message.Builder { public String name; public List layers; public String swamp; public Builder() { layers = Internal.newMutableList(); } public Builder name(String name) { this.name = name; return this; } public Builder layers(List layers) { Internal.checkElementsNotNull(layers); this.layers = layers; return this; } public Builder swamp(String swamp) { this.swamp = swamp; return this; } @Override public Ogre build() { if (name == null) { throw Internal.missingRequiredFields(name, "name"); } return new Ogre(name, layers, swamp, super.buildUnknownFields()); } }

Slide 32

Slide 32 text

public static final class Builder extends Message.Builder { public String name; public List layers; public String swamp; public Builder() { layers = Internal.newMutableList(); } public Builder name(String name) { this.name = name; return this; } public Builder layers(List layers) { Internal.checkElementsNotNull(layers); this.layers = layers; return this; } public Builder swamp(String swamp) { this.swamp = swamp; return this; } @Override public Ogre build() { if (name == null) { throw Internal.missingRequiredFields(name, "name"); } return new Ogre(name, layers, swamp, super.buildUnknownFields()); } } Internal.checkElementsNotNull(layers); if (name == null) { throw Internal.missingRequiredFields(name, "name"); }

Slide 33

Slide 33 text

public static final class Builder extends Message.Builder { public String name; public List layers; public String swamp; public Builder() { layers = Internal.newMutableList(); } public Builder name(String name) { this.name = name; return this; } public Builder layers(List layers) { Internal.checkElementsNotNull(layers); this.layers = layers; return this; } public Builder swamp(String swamp) { this.swamp = swamp; return this; } @Override public Ogre build() { if (name == null) { throw Internal.missingRequiredFields(name, "name"); } return new Ogre(name, layers, swamp, super.buildUnknownFields()); } }

Slide 34

Slide 34 text

class Ogre @JvmOverloads constructor( @JvmField val name: String, @JvmField val layers: List @JvmField val swamp: String? unknownFields: ByteString = ByteString.EMPTY ) : Message(ADAPTER, unknownFields) @JvmField val name: String, @JvmField val layers: List = emptyList(), @JvmField val swamp: String? = null,

Slide 35

Slide 35 text

val shrek = Ogre( name = "shrek", layers = listOf(1, 2), swamp = null )

Slide 36

Slide 36 text

Ogre shrek = new Ogre();

Slide 37

Slide 37 text

Ogre shrek = new Ogre("Shrek", Arrays.asList(1, 2), "Shrek");

Slide 38

Slide 38 text

Java Interop

Slide 39

Slide 39 text

class Ogre( @JvmField val name: String, @JvmField val layers: List = emptyList(), @JvmField val swamp: String? = null ) interface @JvmField val name: String, @JvmField val layers: List = emptyList(), @JvmField val swamp: String? = null

Slide 40

Slide 40 text

interface Ogre { val name: String val layers: List val swamp: String? }

Slide 41

Slide 41 text

interface Ogre { val name: String val layers: List val swamp: String? } shrek.getLayers();

Slide 42

Slide 42 text

inline fun Ogre.findFriendOfType(): T? { for (friend in friends()) { if (friend is T) return friend } return null }

Slide 43

Slide 43 text

inline fun Ogre.findFriendOfType(): T? { for (friend in friends()) { if (friend is T) return friend } return null }
 
 shrek.findFriendOfType()

Slide 44

Slide 44 text

inline fun Ogre.findFriendOfType(): T? { for (friend in friends()) { if (friend is T) return friend } return null }
 
 shrek.findFriendOfType() shrek.findFriendOfType();

Slide 45

Slide 45 text

inline fun Ogre.findFriendOfType(): T? { for (friendain friends()) { if (friend is T) return friend }Y returnbnull }Z

Slide 46

Slide 46 text

fun Ogre.findFriendOfType(type: Class): T? { for (friend in friends()) { if (type.isInstance(friend)) return friend as T? }B return null }A inline fun Ogre.findFriendOfType(): T? { for (friendain friends()) { if (friend is T) return friend }Y returnbnull }Z findFriendOfType( ::class.java)

Slide 47

Slide 47 text

fun Ogre.findFriendOfType(type: Class): T? { for (friend in friends()) { if (type.isInstance(friend)) return friend as T? }B return null }A inline fun Ogre.findFriendOfType(): T? { returnbfindFriendOfType(T::class.java) }Z

Slide 48

Slide 48 text

interface SwampChangedListener { fun swampChanged(newSwamp: String) } fun addSwampChangedListener(listener: SwampChangedListener) = …

Slide 49

Slide 49 text

interface SwampChangedListener { fun swampChanged(newSwamp: String) }A fun addSwampChangedListener(listener: SwampChangedListener) = … shrek.addSwampChangedListener(new SwampChangedListener() { @Override public void swampChanged(@NotNull String newSwamp) {P System.out.println("What are you doing in " + newSwamp); } });

Slide 50

Slide 50 text

interface SwampChangedListener { fun swampChanged(newSwamp: String) }A fun addSwampChangedListener(listener: SwampChangedListener) = … shrek.addSwampChangedListener(newSwamp -> {P System.out.println("What are you doing in " + newSwamp); });

Slide 51

Slide 51 text

interface SwampChangedListener { fun swampChanged(newSwamp: String) } fun addSwampChangedListener(listener: SwampChangedListener) = …

Slide 52

Slide 52 text

interface SwampChangedListener { fun swampChanged(newSwamp:(String): Unit } fun addSwampChangedListener(listener: SwampChangedListener) = … shrek.addSwampChangedListener(object : SwampChangedListener { override fun swampChanged(newSwamp: String) { System.out.println("What are you doing in $newSwamp") } }) KT-7770

Slide 53

Slide 53 text

fun addSwampChangedListener(listener: (String) -> Unit) = …

Slide 54

Slide 54 text

fun addSwampChangedListener(listener: (String) -> Unit) = … shrek.addSwampChangedListener { newSwamp -> System.out.println("What are you doing in $newSwamp") }

Slide 55

Slide 55 text

fun addSwampChangedListener(listener: (String) -> Unit) = … shrek.addSwampChangedListener { newSwamp -> System.out.println("What are you doing in $newSwamp") } shrek.addSwampChangedListener(newSwamp -> { System.out.println("What are you doing in " + newSwamp); return Unit.INSTANCE; }); KT-21018

Slide 56

Slide 56 text

fun addSwampChangedListener(listener: SwampChangedListener) = … public interface SwampChangedListener { void swampChanged(String newSwamp); }Z

Slide 57

Slide 57 text

fun addSwampChangedListener(listener: SwampChangedListener) = … shrek.addSwampChangedListener(SwampChangedListener { newSwamp -> System.out.println("What are you doing in $newSwamp") }) public interface SwampChangedListener { void swampChanged(String newSwamp); }Z

Slide 58

Slide 58 text

fun addSwampChangedListener(listener: SwampChangedListener) = … public interface SwampChangedListener { void swampChanged(String newSwamp); }Z shrek.addSwampChangedListener(newSwamp -> { System.out.println("What are you doing in " + newSwamp); }); shrek.addSwampChangedListener(SwampChangedListener { newSwamp -> System.out.println("What are you doing in $newSwamp") })

Slide 59

Slide 59 text

sealed class Optional data class Some(val value: T): Optional() object None : Optional()

Slide 60

Slide 60 text

sealed class Optional data class Some(val value: T): Optional() object None : Optional() fun T?.asOptional() = if (this == null) None else Some(this)

Slide 61

Slide 61 text

@file:JvmName("Optionals") sealed class Optional data class Some(val value: T): Optional() object None : Optional() @JvmName("ofNullable") fun T?.asOptional() = if (this == null) None else Some(this)

Slide 62

Slide 62 text

sealed class Optional { companion object { @JvmName("ofNullable") @JvmStatic fun T?.asOptional() = if (this == null) None else Some(this) }Y }Z data class Some(val value: T): Optional() object None : Optional() KT-15286 @file:JvmName("Optionals")

Slide 63

Slide 63 text

sealed class Optional { companion object { @JvmStatic fun ofNullable(value: T?) = value.asOptional() }Y }Z data class Some(val value: T): Optional() object None : Optional() fun T?.asOptional() = if (this == null) None else Some(this) KT-15286 @JvmName

Slide 64

Slide 64 text

@file:JvmName("-Optionals") sealed class Optional { companion object { @JvmStatic fun ofNullable(value: T?) = value.asOptional() }Y }Z data class Some(val value: T): Optional() object None : Optional() fun T?.asOptional() = if (this == null) None else Some(this) KT-15286

Slide 65

Slide 65 text

class Foo ( val bar: Nothing, val listBar: List )

Slide 66

Slide 66 text

class Foo ( val bar: Nothing, val listBar: List ) Void bar = foo.getBar(); List listBar = foo.getListBar();

Slide 67

Slide 67 text

KotlinPoet

Slide 68

Slide 68 text

Type

Slide 69

Slide 69 text

Type Class

Slide 70

Slide 70 text

Type Class Parameterized Type

Slide 71

Slide 71 text

Type String Map

Slide 72

Slide 72 text

val stringClass: KClass = String::class

Slide 73

Slide 73 text

val stringClass: KClass = String::class val stringName: ClassName = stringClass.asClassName()

Slide 74

Slide 74 text

val stringClass: KClass = String::class val stringName: ClassName = stringClass.asClassName() import kotlin.String val foo: String = ""

Slide 75

Slide 75 text

val stringClass: KClass = String::class val stringName: ClassName = stringClass.asClassName() import kotlin.String val foo: String = "" class String

Slide 76

Slide 76 text

val stringClass: KClass = String::class val stringName: ClassName = stringClass.asClassName() class String { val foo: kotlin.String = "" }

Slide 77

Slide 77 text

val stringClass: KClass = String::class val stringName: ClassName = stringClass.asClassName()

Slide 78

Slide 78 text

val stringClass: KClass = String::class val stringName: ClassName = stringClass.asClassName() val mapStringToInt = ParameterizedTypeName.get( Map::class.asTypeName(), stringName, Int::class.asTypeName())

Slide 79

Slide 79 text

val stringClass: KClass = String::class val stringName: ClassName = stringClass.asClassName() val mapStringToInt = ParameterizedTypeName.get( Map::class.asTypeName(), stringName, Int::class.asTypeName()) val nullableMap = mapStringToInt.asNullable()

Slide 80

Slide 80 text

val foo = PropertySpec.builder("foo", String::class) .initializer("%S", "foo") .build()

Slide 81

Slide 81 text

val foo = PropertySpec.builder("foo", String::class) .initializer("%S", "foo") .build() String::class

Slide 82

Slide 82 text

val foo = PropertySpec.builder("foo", String::class) .initializer("%S", "foo") .build() "%S", "foo"

Slide 83

Slide 83 text

val foo = PropertySpec.builder("foo", String::class) .initializer("%S", "foo") .build()

Slide 84

Slide 84 text

val foo = PropertySpec.builder("foo", String::class) .initializer("%S", "foo") .build() println(foo) val foo: kotlin.String = "foo"X

Slide 85

Slide 85 text

val foo = PropertySpec.builder("foo", String::class) .initializer("%S", "foo\tbar") .build() println(foo) val foo: kotlin.String = "foo\tbar"X

Slide 86

Slide 86 text

val foo = PropertySpec.builder("foo", String::class) .initializer("%S", "foo\tbar") .build() println(foo) val foo: kotlin.String = "foo\tbar"X kotlin.String

Slide 87

Slide 87 text

val foo = PropertySpec.builder("foo", String::class) .initializer("%S", "foo\tbar") .build() val file = FileSpec.builder("com.example", "KotlinConf.kt") .addProperty(foo) .build() println(file) package com.example import kotlin.String val foo: String = "foo\tbar"X foo

Slide 88

Slide 88 text

PropertySpec.builder("foo", String::class) .initializer("%S", "foo\tbar") .build() package com.example import kotlin.String val foo: String = "foo\tbar"X

Slide 89

Slide 89 text

FunSpec.builder("main") .addParameter("args", String::class, VARARG) .build() package com.example import kotlin.String fun main(vararg args: String) { }

Slide 90

Slide 90 text

TypeSpec.classBuilder("User") .addModifiers(DATA) .build() package com.example data class User

Slide 91

Slide 91 text

TypeSpec.classBuilder("User") .addModifiers(DATA) .build() package com.example data class User

Slide 92

Slide 92 text

TypeSpec.classBuilder("User") .addModifiers(DATA) .addProperty(PropertySpec.builder("name", String::class).build()) .build()Z package com.example data class User {Y val name: String }X

Slide 93

Slide 93 text

TypeSpec.classBuilder("User") .addModifiers(DATA) .addProperty(PropertySpec.builder("name", String::class).build()) .primaryConstructor(FunSpec.constructorBuilder() .addParameter("name", String::class) .build())A .build()Z package com.example data class User(name: String)G{Y val name: String }X

Slide 94

Slide 94 text

name: String TypeSpec.classBuilder("User") .addModifiers(DATA) .addProperty(PropertySpec.builder("name", String::class) .initializer("name") .build())B .primaryConstructor(FunSpec.constructorBuilder() .addParameter("name", String::class) .build())A .build() package com.example data class User(val name: String)G

Slide 95

Slide 95 text

TypeSpec.classBuilder("User") .addModifiers(DATA) .addProperty(PropertySpec.builder("name", String::class) .initializer("name.toLowerCase()") .build())B .primaryConstructor(FunSpec.constructorBuilder() .addParameter("name", String::class) .build())A .build() package com.example data class User(name: String)G{ val name: String = name.toLowerCase() }X

Slide 96

Slide 96 text

FunSpec.builder("seconds") .receiver(Long::class) .returns(Duration::class) .addStatement("return %T.ofSeconds(this)", Duration::class) .build() package com.example import java.time.Duration import kotlin.Long fun Long.seconds(): Duration = Duration.ofSeconds(this)

Slide 97

Slide 97 text

FunSpec.builder("seconds") .receiver(Long::class) .returns(Duration::class) .addStatement("require(this >= 0L)") .addStatement("return %T.ofSeconds(this)", Duration::class) .build() package com.example import java.time.Duration import kotlin.Long fun Long.seconds(): Duration { require(this >= 0L) return Duration.ofSeconds(this) }

Slide 98

Slide 98 text

FunSpec.builder("seconds") .receiver(Long::class) .returns(Duration::class) .addStatement("require(this >= 0L)") .addStatement("return %T.ofSeconds(this)", Duration::class) .build()

Slide 99

Slide 99 text

val longSeconds = FunSpec.builder("seconds") .receiver(Long::class) .returns(Duration::class) .addStatement("require(this >= 0L)") .addStatement("return %T.ofSeconds(this)", Duration::class) .build()

Slide 100

Slide 100 text

val longSeconds = FunSpec.builder("seconds") .receiver(Long::class) .returns(Duration::class) .addStatement("require(this >= 0L)") .addStatement("return %T.ofSeconds(this)", Duration::class) .build() FunSpec.builder("main") .addParameter("args", String::class, VARARG) .addStatement("println(%L.%N())", 2L, longSeconds) .build()

Slide 101

Slide 101 text

val longSeconds = FunSpec.builder("seconds") .receiver(Long::class) .returns(Duration::class) .addStatement("require(this >= 0L)") .addStatement("return %T.ofSeconds(this)", Duration::class) .build() FunSpec.builder("main") .addParameter("args", String::class, VARARG) .addStatement("println(%L.%N())", 2L, longSeconds) .build() %N longSeconds

Slide 102

Slide 102 text

val longSeconds = FunSpec.builder("seconds") .receiver(Long::class) .returns(Duration::class) .addStatement("require(this >= 0L)") .addStatement("return %T.ofSeconds(this)", Duration::class) .build() FunSpec.builder("main") .addParameter("args", String::class, VARARG) .addStatement("println(%L.%N())", 2L, longSeconds) .build() fun main(vararg args: String) { println(2L.seconds()) }

Slide 103

Slide 103 text

val code = CodeBlock.builder()

Slide 104

Slide 104 text

val code = CodeBlock.builder() code.addStatement("val foo = %T.MIN_VALUE", Int::class)

Slide 105

Slide 105 text

val code = CodeBlock.builder() code.addStatement("val foo = %T.MIN_VALUE", Int::class) code.add("val bar = ") when (answer) { YES -> code.add("0L") NO -> code.add("%T.MIN_VALUE", Int::class) } code.add(".toString()\n")

Slide 106

Slide 106 text

val code = CodeBlock.builder() code.addStatement("val foo = %T.MIN_VALUE", Int::class) code.add("val bar = ") when (answer) { YES -> code.add("0L") NO -> code.add("%T.MIN_VALUE", Int::class) } code.add(".toString()\n") code.beginControlFlow("if (bar.isEmpty())") .addStatement("println(%S)", "Empty!") .nextControlFlow("else") .addStatement("println(bar)") .endControlFlow()

Slide 107

Slide 107 text

val intMin = CodeBlock.of("%T.MIN_VALUE", Int::class) val intMax = CodeBlock.of("%T.MAX_VALUE", Int::class) val longMin = CodeBlock.of("%T.MIN_VALUE", Long::class) val longMax = CodeBlock.of("%T.MAX_VALUE", Long::class) val values = listOf(intMin, intMax, longMin, longMax)

Slide 108

Slide 108 text

val intMin = CodeBlock.of("%T.MIN_VALUE", Int::class) val intMax = CodeBlock.of("%T.MAX_VALUE", Int::class) val longMin = CodeBlock.of("%T.MIN_VALUE", Long::class) val longMax = CodeBlock.of("%T.MAX_VALUE", Long::class) val values = listOf(intMin, intMax, longMin, longMax) // elsewhere val list = values.joinToCode(prefix = "listOf(", suffix = ")")

Slide 109

Slide 109 text

val intMin = CodeBlock.of("%T.MIN_VALUE", Int::class) val intMax = CodeBlock.of("%T.MAX_VALUE", Int::class) val longMin = CodeBlock.of("%T.MIN_VALUE", Long::class) val longMax = CodeBlock.of("%T.MAX_VALUE", Long::class) val values = listOf(intMin, intMax, longMin, longMax) // elsewhere val list = values.joinToCode(prefix = "listOf(", suffix = ")") listOf(Int.MIN_VALUE, Int.MAX_VALUE, Long.MIN_VALUE, Long.MAX_VALUE)

Slide 110

Slide 110 text

inline fun (String.() -> R).crazy(noinline foo: T.(R?) -> Unit) where T : Runnable, T : Closeable = 42L

Slide 111

Slide 111 text

val typeT = TypeVariableName("T", Runnable::class, Closeable::class) val typeR = TypeVariableName("R", CharSequence::class) val stringExtToR = LambdaTypeName.get(String::class.asClassName(), returnType = typeR) val tRtoUnit = LambdaTypeName.get(typeT, parameters = typeR.asNullable(), returnType = UNIT) val crazy = FunSpec.builder("crazy") .addModifiers(INLINE) .receiver(stringExtToR) .addTypeVariable(typeT.reified()) .addTypeVariable(typeR) .addParameter("foo", tRtoUnit, NOINLINE) .addStatement("return 42L") .build() inline fun (String.() -> R).crazy(noinline foo: T.(R?) -> Unit) where T : Runnable, T : Closeable = 42L

Slide 112

Slide 112 text

Kotlin Compatible Code

Slide 113

Slide 113 text

@Nullable public String getSwamp() { return swamp; }

Slide 114

Slide 114 text

@Nullable public String getSwamp() { return swamp; } val swamp: String? = shrek.swamp

Slide 115

Slide 115 text

Bytecode Build tool

Slide 116

Slide 116 text

Bytecode Build tool

Slide 117

Slide 117 text

interface Foo { val bar: String }

Slide 118

Slide 118 text

public abstract interface com/sample/Foo { // access flags 0x401 public abstract getBar()Ljava/lang/String; @Lorg/jetbrains/annotations/NotNull;() // invisible LOCALVARIABLE this Lcom/sample/Foo; L0 L1 0 @Lkotlin/Metadata;(
 mv={1, 1, 7},
 bv={1, 0, 2},
 k=1,
 d1={“…”},
 d2={"Lcom/sample/Foo;", "", "bar", "", “getBar" }
 ) // compiled from: Foo.kt }

Slide 119

Slide 119 text

public abstract interface com/sample/Foo { // access flags 0x401 public abstract getBar()Ljava/lang/String; @Lorg/jetbrains/annotations/NotNull;() // invisible LOCALVARIABLE this Lcom/sample/Foo; L0 L1 0 @Lkotlin/Metadata;(
 mv={1, 1, 7},
 bv={1, 0, 2},
 k=1,
 d1={“…”},
 d2={"Lcom/sample/Foo;", "", "bar", "", “getBar" }
 ) // compiled from: Foo.kt } goo.gl/GcT9gz

Slide 120

Slide 120 text

github.com/Takhion/kotlin-metadata org.jetbrains.kotlin.serialization.ProtoBuf.Class

Slide 121

Slide 121 text

github.com/Takhion/kotlin-metadata org.jetbrains.kotlin.serialization.ProtoBuf.Class

Slide 122

Slide 122 text

github.com/Takhion/kotlin-metadata org.jetbrains.kotlin.serialization.ProtoBuf.Class

Slide 123

Slide 123 text

github.com/Takhion/kotlin-metadata org.jetbrains.kotlin.serialization.ProtoBuf.Class

Slide 124

Slide 124 text

github.com/Takhion/kotlin-metadata org.jetbrains.kotlin.serialization.ProtoBuf.Class

Slide 125

Slide 125 text

github.com/Takhion/kotlin-metadata org.jetbrains.kotlin.serialization.ProtoBuf.Class

Slide 126

Slide 126 text

public abstract interface com/sample/Foo { // access flags 0x401 public abstract getBar()Ljava/lang/String; @Lorg/jetbrains/annotations/NotNull;() // invisible LOCALVARIABLE this Lcom/sample/Foo; L0 L1 0 @Lkotlin/Metadata;(
 mv={1, 1, 7},
 bv={1, 0, 2},
 k=1,
 d1={“…”},
 d2={"Lcom/sample/Foo;", "", "bar", "", “getBar" }
 ) // compiled from: Foo.kt }

Slide 127

Slide 127 text

Bytecode

Slide 128

Slide 128 text

Bytecode

Slide 129

Slide 129 text

public abstract interface com/sample/Foo { // access flags 0x401 public abstract getBar()Ljava/lang/String; @Lorg/jetbrains/annotations/NotNull;() // invisible LOCALVARIABLE this Lcom/sample/Foo; L0 L1 0 @Lkotlin/Metadata;(
 mv={1, 1, 7},
 bv={1, 0, 2},
 k=1,
 d1={“…”},
 d2={"Lcom/sample/Foo;", "", "bar", "", “getBar" }
 )g // compiled from: Foo.kt }A

Slide 130

Slide 130 text

public abstract interface com/sample/Foo { // access flags 0x401 public abstract getBar()Ljava/lang/String; @Lorg/jetbrains/annotations/NotNull;() // invisible LOCALVARIABLE this Lcom/sample/Foo; L0 L1 0 @Lkotlin/Metadata;(
 mv={1, 1, 7},
 bv={1, 0, 2},
 k=1,
 d1={“…”},
 d2={"Lcom/sample/Foo;", "", "bar", "", “getBar" }
 )g // compiled from: Foo.kt }A

Slide 131

Slide 131 text

public abstract interface com/sample/Foo { // access flags 0x401 public abstract getBar()Ljava/lang/String; @Lorg/jetbrains/annotations/NotNull;() // invisible LOCALVARIABLE this Lcom/sample/Foo; L0 L1 0 @Lkotlin/Metadata;(
 mv={1, 1, 7},
 bv={1, 0, 2},
 k=1,
 d1={“…”},
 d2={"Lcom/sample/Foo;", "", "bar", "", “getBar" }
 ) // compiled from: Foo.kt } {A AnnotationVisitor av1 = av0.visitArray("d2"); av1.visit(null, "Lcom/sample/Foo;"); av1.visit(null, ""); av1.visit(null, "bar"); av1.visit(null, ""); av1.visit(null, "getBar"); av1.visit(null, "()I"); av1.visitEnd(); }B {C mv = cw.visitMethod(ACC_PUBLIC + ACC_ABSTRACT, "getBar", "()I", null, null); mv.visitEnd(); }D

Slide 132

Slide 132 text

{A AnnotationVisitor av1 = av0.visitArray("d2"); av1.visit(null, "Lcom/sample/Foo;"); av1.visit(null, ""); av1.visit(null, "bar"); av1.visit(null, ""); av1.visit(null, "getBar"); av1.visit(null, "()I"); av1.visitEnd(); }B {C mv = cw.visitMethod(ACC_PUBLIC + ACC_ABSTRACT, "getBar", "()I", null, null); mv.visitEnd(); }D b b

Slide 133

Slide 133 text

{A AnnotationVisitor av1 = av0.visitArray("d2"); av1.visit(null, "Lcom/sample/Foo;"); av1.visit(null, ""); av1.visit(null, "bar"); av1.visit(null, ""); av1.visit(null, "bar"); av1.visit(null, "()I"); av1.visitEnd(); }B {C mv = cw.visitMethod(ACC_PUBLIC + ACC_ABSTRACT, "bar", "()I", null, null); mv.visitEnd(); }D

Slide 134

Slide 134 text

{A AnnotationVisitor av1 = av0.visitArray("d2"); av1.visit(null, "Lcom/sample/Foo;"); av1.visit(null, ""); av1.visit(null, "bar"); av1.visit(null, ""); av1.visit(null, "bar"); av1.visit(null, "()I"); av1.visitEnd(); }B {C mv = cw.visitMethod(ACC_PUBLIC + ACC_ABSTRACT, "bar", "()I", null, null); mv.visitEnd(); }D

Slide 135

Slide 135 text

{ AnnotationVisitor av1 = av0.visitArray("d2"); av1.visit(null, "Lcom/sample/Foo;"); av1.visit(null, ""); av1.visit(null, "bar"); av1.visit(null, ""); av1.visit(null, "bar"); av1.visit(null, "()I"); av1.visitEnd(); } { mv = cw.visitMethod(ACC_PUBLIC + ACC_ABSTRACT, "bar", "()I", null, null); mv.visitEnd(); } public abstract interface com/sample/Foo { // access flags 0x401 public abstract bar()Ljava/lang/String; @Lorg/jetbrains/annotations/NotNull;() // invisible LOCALVARIABLE this Lcom/sample/Foo; L0 L1 0 @Lkotlin/Metadata;(
 mv={1, 1, 7},
 bv={1, 0, 2},
 k=1,
 d1={“…”},
 d2={"Lcom/sample/Foo;", "", "bar", "", “bar” }
 ) // compiled from: Foo.kt }

Slide 136

Slide 136 text

class KotlinFoo(override val bar: Int): Foo
 
 class JavaFoo implements Foo { @Override public int bar() { return 0; } }

Slide 137

Slide 137 text

void setPadding(int l, int t, int r, int b) { // … }

Slide 138

Slide 138 text

void setPadding(int l, int t, int r, int b) { // … }z view.setPadding(10, 0, 0, 10)

Slide 139

Slide 139 text

void setPadding(int l, int t, int r, int b) { // … }z view.setPadding(left = 10, bottom = 10)

Slide 140

Slide 140 text

Bytecode

Slide 141

Slide 141 text

Multiplatform

Slide 142

Slide 142 text

Bytecode

Slide 143

Slide 143 text

Bytecode

Slide 144

Slide 144 text

Bytecode LLVM

Slide 145

Slide 145 text

enum class Direction { NORTH, SOUTH, EAST, WEST } class GamePeice( movement: Set = EnumSet.of(Direction.NORTH) )Z

Slide 146

Slide 146 text

enum class Direction { NORTH, SOUTH, EAST, WEST } class GamePeice( movement: Set = EnumSet.of(Direction.NORTH) )Z EnumSet.of

Slide 147

Slide 147 text

import java.util.EnumSet enum class Direction { NORTH, SOUTH, EAST, WEST } class GamePeice( movement: Set = EnumSet.of(Direction.NORTH) )Z s O EnumSet.of

Slide 148

Slide 148 text

enum class Direction { NORTH, SOUTH, EAST, WEST } class GamePeice( movement: Set = setOf(Direction.NORTH) )Z S o

Slide 149

Slide 149 text

import com.google.common.collect @AutoImplement interface Party { val people: ImmutableList }

Slide 150

Slide 150 text

import com.google.common.collect @AutoImplement interface Party { val people: ImmutableList } import com.google.common.collect @Generated class AutoParty(override val people: ImmutableList) : Party

Slide 151

Slide 151 text

CREATE TABLE user( name TEXT NOT NULL, location TEXT AS android.location.Location )

Slide 152

Slide 152 text

CREATE TABLE user( name TEXT NOT NULL, location TEXT AS android.location.Location ) import android.location.Location data class User( val name: String, val location: Location )

Slide 153

Slide 153 text

@file:JvmName("ByteStrings") @JvmName("from") fun ByteArray.asByteString(): ByteString = …

Slide 154

Slide 154 text

@file:JvmName("ByteStrings") @JvmName("from") fun ByteArray.asByteString(): ByteString = … byte[] bytes = … ByteString b = ByteStrings.from(bytes);

Slide 155

Slide 155 text

@file:JvmName("ByteStrings") @JvmName("from") fun ByteArray.asByteString(): ByteString = … byte[] bytes = … ByteString b = ByteStrings.from(bytes); Cannot access 'JvmName': it is internal in 'kotlin.jvm' KT-19507 s

Slide 156

Slide 156 text

@JsName("from") fun ByteArray.asByteString(): ByteString = … @file:JvmName("ByteStrings")

Slide 157

Slide 157 text

@JsName("from") fun ByteArray.asByteString(): ByteString = … @file:JvmName("ByteStrings") KT-19508

Slide 158

Slide 158 text

Verbosity is okay. API is the #1 priority.

Slide 159

Slide 159 text

Verbosity is okay. API is the #1 priority. If you do any kind of Java codegen, keep Kotlin in mind.

Slide 160

Slide 160 text

Verbosity is okay. API is the #1 priority. If you do any kind of Java codegen, keep Kotlin in mind. Don’t depend on platform types unless the user does.

Slide 161

Slide 161 text

KotlinPoet 0.6.0 released!

Slide 162

Slide 162 text

@Strongolopolis & @JakeWharton Kotlin Code Generation