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Kotlin in Production

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@goncalossilva j.mp/kotlininproduction

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No content

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Java?

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Alternatives?

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1 Modern

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1 Modern 2 Fast

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1 Modern 2 Fast 3 Small

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1 Modern 2 Fast 3 Small 4 Interoperable

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Scala

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1 Modern Scala

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1 Modern 2 Fast Scala

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1 Modern 2 Fast 3 Small Scala

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1 Modern 2 Fast 3 Small 4 Interoperable Scala

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Clojure

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1 Modern Clojure

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1 Modern 2 Fast Clojure

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1 Modern 2 Fast 3 Small Clojure

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1 Modern 2 Fast 3 Small 4 Interoperable Clojure

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Groovy

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1 Modern Groovy

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1 Modern 2 Fast Groovy

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1 Modern 2 Fast 3 Small Groovy

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1 Modern 2 Fast 3 Small 4 Interoperable Groovy

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Swift

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Swift Modern Fast Small Interoperable

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Java 10

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Java 10 Modern Fast Small Interoperable

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Kotlin

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1 Modern 2 Fast 3 Small 4 Interoperable Kotlin

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class Purchase constructor(value: Int, success: Boolean) { val value = value val success = success }

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class Purchase(val value: Int, val success: Boolean)

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data class Purchase(val value: Int, val success: Boolean)

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data class Customer(val name: String, val purchases: List) data class Purchase(val value: Int, val success: Boolean)

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data class Customer(val name: String, val purchases: List) data class Purchase(val value: Int, val success: Boolean) object Dataset { val customers: MutableList = ArrayList() init { customers.add(Customer( "Gonçalo”, arrayListOf(Purchase(42, true), Purchase(9000, false)))) } }

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fun successfulPurchases(name: String) : List { val successfulPurchases: MutableList = ArrayList() var customer: Customer? = null for (c in Dataset.customers) { if (c.name == name) { customer = c break } } if (customer != null) { for (purchase in customer.purchases) { if (purchase.success) successfulPurchases.add(purchase) } } return successfulPurchases }

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fun successfulPurchases(name: String) : List { val successfulPurchases: MutableList = ArrayList() var customer: Customer? = null for (c in Dataset.customers) { if (c.name == name) { customer = c break } } if (customer != null) { for (purchase in customer.purchases) { if (purchase.success) successfulPurchases.add(purchase) } } return successfulPurchases }

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fun successfulPurchases(name: String) : List { val successfulPurchases: MutableList = ArrayList() var customer: Customer? = null for (c in Dataset.customers) { if (c.name == name) { customer = c break } } if (customer != null) { for (purchase in customer.purchases) { if (purchase.success) successfulPurchases.add(purchase) } } return successfulPurchases }

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fun successfulPurchases(name: String) : List { val successfulPurchases: MutableList = ArrayList() var customer: Customer? = null for (c in Dataset.customers) { if (c.name == name) { customer = c break } } if (customer != null) { for (purchase in customer.purchases) { if (purchase.success) successfulPurchases.add(purchase) } } return successfulPurchases }

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fun successfulPurchases(name: String) : List { val successfulPurchases: MutableList = ArrayList() var customer: Customer? = null for (c in Dataset.customers) { if (c.name == name) { customer = c break } } if (customer != null) { for (purchase in customer.purchases) { if (purchase.success) successfulPurchases.add(purchase) } } return successfulPurchases }

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fun successfulPurchases(name: String) : List { val successfulPurchases: MutableList = ArrayList() var customer: Customer? = null for (c in Dataset.customers) { if (c.name == name) { customer = c break } } if (customer != null) { for (purchase in customer.purchases) { if (purchase.success) successfulPurchases.add(purchase) } } return successfulPurchases }

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fun successfulPurchases(name: String) : List { val successfulPurchases: MutableList = ArrayList() // Find the customer. val customer = Dataset.customers.find { it.name == name } // Gather successful purchases. if (customer != null) { successfulPurchases.addAll(customer.purchases.filter { it.success }) } return successfulPurchases }

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fun successfulPurchases(name: String) : List { return Dataset.customers.find { it.name == name }?.purchases? .filter { it.success } ?: emptyList() }

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fun successfulPurchases(name: String) : List { return Dataset.customers.find { it.name == name }?.purchases? .filter { it.success } ?: emptyList() }

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fun successfulPurchases(name: String) : List { return Dataset.customers.find { it.name == name }?.purchases? .filter { it.success } ?: emptyList() }

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fun successfulPurchases(name: String) : List { return Dataset.customers.find { it.name == name }?.purchases? .filter { it.success } ?: emptyList() }

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fun successfulPurchases(name: String) : List = Dataset.customers.find { it.name == name }?.purchases? .filter { it.success } ?: emptyList()

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fun successfulPurchases(name: String) : List? = Dataset.customers.find { it.name == name }?.purchases?.filter { it.success }

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fun Customer.successfulPurchases() : List = purchases.filter { it.success } customer.successfulPurchases() // Works!

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fun successfulPurchases(name: String) : List { val successfulPurchases: MutableList = ArrayList() var customer: Customer? = null for (c in Dataset.customers) { if (c.name == name) { customer = c break } } if (customer != null) { for (purchase in customer.purchases) { if (purchase.success) successfulPurchases.add(purchase) } } return successfulPurchases }

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fun successfulPurchases(name: String) : List = Dataset.customers.find { it.name == name }?.purchases? .filter { it.success } ?: emptyList()

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Higher-order functions, properties, mixins and delegation, extension functions, static nullability checking, automatic casts, reified generics, declaration-site variance, modules and build infrastructure, inline functions, operator overloading, String interpolation, pattern matching, first class IDE support, Java converter, default parameters, infix methods, destructuring declarations, and more...

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Modern 2 Fast 3 Small 4 Interoperable Kotlin

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Statically typed byte code Inlined lambdas github.com/JetBrains/kotlin-benchmarks Kotlin

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Modern Fast 3 Small 4 Interoperable Kotlin

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5k methods 1MB Smaller and smaller Kotlin

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Modern Fast Small 4 Interoperable Kotlin

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100% interoperable Idiomatic Kotlin with idiomatic Java Annotations for customization Kotlin

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Modern Fast Small Interoperable Kotlin

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Modern Fast Small Interoperable Kotlin 5 Android APIs

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db.beginTransaction() try { db.delete("hackathon", "name = ?", arrayOf("Pixels Camp")) db.setTransactionSuccessful() } finally { db.endTransaction() }

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inline fun SQLiteDatabase.inTransaction(func: SQLiteDatabase.() -> Unit) { beginTransaction() try { func() setTransactionSuccessful() } finally { endTransaction() } } db.inTransaction { delete("hackathon", "name = ?", arrayOf("Pixels Camp")) }

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inline fun SQLiteDatabase.inTransaction(func: SQLiteDatabase.() -> Unit) { beginTransaction() try { func() setTransactionSuccessful() } finally { endTransaction() } } db.inTransaction { delete("hackathon", "name = ?", arrayOf("Pixels Camp")) }

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inline fun SQLiteDatabase.inTransaction(func: SQLiteDatabase.() -> Unit) { beginTransaction() try { func() setTransactionSuccessful() } finally { endTransaction() } } db.inTransaction { delete("hackathon", "name = ?", arrayOf("Pixels Camp")) }

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inline fun SQLiteDatabase.inTransaction(func: SQLiteDatabase.() -> Unit) { beginTransaction() try { func() setTransactionSuccessful() } finally { endTransaction() } } db.inTransaction { delete("hackathon", "name = ?", arrayOf("Pixels Camp")) }

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fun Cursor.getStringOrNull(columnName: String): String? { val index = getColumnIndexOrThrow(columnName) return if (isNull(index)) null else getString(index) } fun View.setPaddingTop(top: Int) { setPadding(paddingLeft, top, paddingRight, paddingBottom) } fun View.toBitmap() : Bitmap? { if (width > 0 && height > 0) { val bitmap = Bitmap.createBitmap(width, height, Bitmap.Config.ARGB_8888) val canvas = Canvas(bitmap) draw(canvas) return bitmap } else { return null } }

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fun Cursor.getStringOrNull(columnName: String): String? { val index = getColumnIndexOrThrow(columnName) return if (isNull(index)) null else getString(index) } fun View.setPaddingTop(top: Int) { setPadding(paddingLeft, top, paddingRight, paddingBottom) } fun View.toBitmap() : Bitmap? { if (width > 0 && height > 0) { val bitmap = Bitmap.createBitmap(width, height, Bitmap.Config.ARGB_8888) val canvas = Canvas(bitmap) draw(canvas) return bitmap } else { return null } }

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fun Cursor.getStringOrNull(columnName: String): String? { val index = getColumnIndexOrThrow(columnName) return if (isNull(index)) null else getString(index) } fun View.setPaddingTop(top: Int) { setPadding(paddingLeft, top, paddingRight, paddingBottom) } fun View.toBitmap() : Bitmap? { if (width > 0 && height > 0) { val bitmap = Bitmap.createBitmap(width, height, Bitmap.Config.ARGB_8888) val canvas = Canvas(bitmap) draw(canvas) return bitmap } else { return null } }

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fun Cursor.getStringOrNull(columnName: String): String? { val index = getColumnIndexOrThrow(columnName) return if (isNull(index)) null else getString(index) } fun View.setPaddingTop(top: Int) { setPadding(paddingLeft, top, paddingRight, paddingBottom) } fun View.toBitmap() : Bitmap? { if (width > 0 && height > 0) { val bitmap = Bitmap.createBitmap(width, height, Bitmap.Config.ARGB_8888) val canvas = Canvas(bitmap) draw(canvas) return bitmap } else { return null } }

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fun Cursor.getStringOrNull(columnName: String): String? { val index = getColumnIndexOrThrow(columnName) return if (isNull(index)) null else getString(index) } fun View.setPaddingTop(top: Int) { setPadding(paddingLeft, top, paddingRight, paddingBottom) } fun View.toBitmap() : Bitmap? { if (width > 0 && height > 0) { val bitmap = Bitmap.createBitmap(width, height, Bitmap.Config.ARGB_8888) val canvas = Canvas(bitmap) draw(canvas) return bitmap } else { return null } }

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Modern Fast Small Interoperable Kotlin Android APIs

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Supported?

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Beyond Android & JVM

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Kotlin Koans https://kotlinlang.org/docs/tutorials/koans.html Kotlin and Android https://developer.android.com/kotlin/index.html Kotlin Slack http://slack.kotlinlang.org/ Resources

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@goncalossilva j.mp/kotlininproduction Thank you