AlexeySoshin

import com.google.protobuf.gradle.*
...
protobuf {
    ...
    generatedFilesBaseDir = "$buildDir/generated-sources"
    ...
    dependencies {
        protobuf(files(project.properties["protoDir"].toString()))
    }
    generateProtoTasks {

AlexeySoshin

fun Tree<Int>.sum(): Long = when (this) {
    Empty -> 0
    is Node -> value + left.sum() + right.sum()
}

AlexeySoshin

sealed class Tree<out T>

AlexeySoshin

data class Node<T>(
    val value: T,
    val left: Tree<T> = Empty,
    val right: Tree<T> = Empty
) : Tree<T>()

AlexeySoshin

object Empty : Tree<Nothing>() {
    override fun toString() = "Empty"
}

AlexeySoshin

val tree = Node(
    42,
    Empty,
    Node(62)
)

println(tree)

AlexeySoshin

sealed class Tree<out T>

AlexeySoshin

sealed class Tree<out T>

object Empty : Tree<Nothing>() {
    override fun toString() = "Empty"
}

data class Node<T>(
    val value: T,
    val left: Tree<T> = Empty,
    val right: Tree<T> = Empty

AlexeySoshin

public SQLClient getConnection(Handler<AsyncResult<SQLConnection>> handler) {
  Context ctx = vertx.getOrCreateContext();
  getConnection(ctx, ar -> ctx.runOnContext(v -> handler.handle(ar)));
  return this;
}

AlexeySoshin

public void execute(Connection conn, 
                    TaskQueue statementsQueue, 
                    Handler<AsyncResult<T>> resultHandler) {
  ctx.executeBlocking(future -> handle(conn, future), 
                      statementsQueue, resultHandler);
}