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Kotlin Code Generation Alec Strong & Jake Wharton

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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 )

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Bytecode

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Protocol Buffers

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Protocol Buffers SQL

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Protocol Buffers SQL Swagger

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Protocol Buffers SQL Swagger Android XML

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Protocol Buffers SQL Swagger Android XML YAML

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SQL Swagger Android XML YAML Mirrors/Elements

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Swagger Android XML YAML Mirrors/Elements PSI

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Android XML YAML Mirrors/Elements PSI UAST

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YAML Mirrors/Elements PSI UAST ???

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

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Protocol Buffers

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

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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; }

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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;

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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

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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)

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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

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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; }

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

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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

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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

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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() }

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

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

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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

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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

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

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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()); } }

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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"); }

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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()); } }

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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,

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

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Ogre shrek = new Ogre();

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

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Java Interop

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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

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

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

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

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

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

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

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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)

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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

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

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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); } });

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

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

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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

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

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

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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

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

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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

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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") })

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

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

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@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)

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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")

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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

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@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

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

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

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KotlinPoet

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Type

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Type Class

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Type Class Parameterized Type

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Type String Map

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val stringClass: KClass = String::class

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

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

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

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

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

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

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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()

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

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

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

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

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

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

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

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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

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

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

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

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

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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

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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

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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

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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

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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)

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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) }

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

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

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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()

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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

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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()) }

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val code = CodeBlock.builder()

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

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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")

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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()

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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)

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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 = ")")

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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)

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

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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

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Kotlin Compatible Code

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

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

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Bytecode Build tool

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Bytecode Build tool

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interface Foo { val bar: String }

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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 }

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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

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

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

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

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

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

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

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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 }

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Bytecode

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Bytecode

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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

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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

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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

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{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

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{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

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{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

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{ 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 }

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

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

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

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

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Bytecode

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Multiplatform

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Bytecode

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Bytecode

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Bytecode LLVM

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

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

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

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

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

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

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

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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 )

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

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

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@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

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

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

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Verbosity is okay. API is the #1 priority.

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

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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.

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KotlinPoet 0.6.0 released!

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@Strongolopolis & @JakeWharton Kotlin Code Generation