sshark

package org.teckhooi

import scala.language.implicitConversions

trait Show[A] {
  def show(a: A): String
}

trait ShowOps {
  def show: String

sshark

package org.teckhooi.foo;

import java.util.Objects;

public class WhosFirst {
    static private Long t1 = null;
    static private Long t2 = null;
    static private Object lock = new Object();
    static private long startMillis = 0;

sshark

package org.teckhooi.bar;

import java.util.Map;
import java.util.Objects;

public class Leaf implements Tree {
    private String value;

    public Leaf(String value) {
        this.value = value;

sshark

object FooBar {
  
  // Basically Java code written using Scala syntax. Similar to using if to check for errors i.e. if (err != nil) {...}
  object Foo extends App {
    def addMin(a: Int, b: Int): Int =
      if (a + b < 10) throw new Exception("Sum is less than 10") else a + b

    def mulMin(a: Int, b: Int): Int =
      if (a * b < 100) throw new Exception("Product is less than 100") else a * b

sshark

 import Math.*

 def maxDiff(xs: List[Int]): Int = 
    xs.scanLeft(Int.MaxValue)(min)
        .tail
        .zip(xs)
        .map(x => x._2 - x._1)
        .filter(_ > 0)
        .fold(-1)(max)       

sshark

import cats.{Applicative, ApplicativeError}
import cats.implicits._

object ApplicationErrorExampleApp extends App {

  val f: List[Int] => Int = (xs: List[Int]) => xs.sum
  val g: List[Int] => Int = (xs: List[Int]) => xs.size

  val xs = List(List(1, 2, 3))

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/*
 *  Setting the right time for the targeted zone e.g. Asia/Singapore
 *       LocalDateTime.now(ZoneId.of("Asia/Singapore")) // set the time of the targeted time zone
 *         .atZone(ZoneId.of("Asia/Singapore"))         // set the time zone ONLY for the time above. Doesn't affect time
 *         .toEpochSecond()                             // find the UTC time for the time at the timezone and convert it to seconds
 */
System.out.println(LocalDateTime.now(ZoneId.of("Asia/Singapore")).atZone(ZoneId.of("Asia/Singapore")).toEpochSecond());

/*

sshark

2021-05-19 03:07:06,927 ERROR dev.miku.r2dbc.mysql.client.ReactorNettyClient [reactor-tcp-epoll-1] Error: readAddress(..) failed: Connection reset by peer
io.netty.channel.unix.Errors$NativeIoException: readAddress(..) failed: Connection reset by peer
2021-05-19 03:07:06,928 ERROR reactor.core.publisher.Operators [reactor-tcp-epoll-1] Operator called default onErrorDropped
dev.miku.r2dbc.mysql.client.MySqlConnectionClosedException: Connection closed
	at dev.miku.r2dbc.mysql.client.ClientExceptions.expectedClosed(ClientExceptions.java:36)
	at dev.miku.r2dbc.mysql.client.ReactorNettyClient.handleClose(ReactorNettyClient.java:262)
	at dev.miku.r2dbc.mysql.client.ReactorNettyClient.access$400(ReactorNettyClient.java:53)
	at dev.miku.r2dbc.mysql.client.ReactorNettyClient$ResponseSubscriber.onComplete(ReactorNettyClient.java:306)
	at reactor.core.publisher.Operators$MultiSubscriptionSubscriber.onComplete(Operators.java:2016)
	at reactor.core.publisher.Operators$MonoSubscriber.onComplete(Operators.java:1824)

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case class Foo(title: String, ids: Set[String])

val xs =
  List((123, "aa", "bb"), (233, "aa", "cc"), (233, "aa", ""), (233, "aa", "cc"), (334, "bb", "ee"))

val m = xs.groupBy(_._2).map { case (k, v) => Foo(k, v.map(_._3).filter(_.nonEmpty).toSet) }

println(m)

/*

sshark

package org.teckhooi

import cats.effect.{ExitCode, IO, IOApp}
import cats.implicits.catsSyntaxEitherId

import scala.util.Try

object EitherErrorHandlingInIO extends IOApp {

  override def run(args: List[String]): IO[ExitCode] = {