jdegoes

Applied Functional Programming with Scala - Notes

Copyright © 2016-2018 Fantasyland Institute of Learning. All rights reserved.

1. Mastering Functions

A function is a mapping from one set, called a domain, to another set, called the codomain. A function associates every element in the domain with exactly one element in the codomain. In Scala, both domain and codomain are types.

val square : Int => Int = x => x * x

jrudolph

package akka.http.scaladsl

import java.io.File

import akka.http.scaladsl.unmarshalling.Unmarshal
import akka.util.ByteString

import scala.concurrent.duration._

import akka.actor.ActorSystem

jarvys

• create a new redis .conf file

$ cp /etc/redis.conf /etc/redis-xxx.conf

• edit /etc/redis-xxx.conf, illustrated as below

...

milessabin

scala> import shapeless._, record._
import shapeless._
import record._

scala> case class Person(name: String, address: String, age: Int)
defined class Person

scala> val joe = Person("Joe", "Brighton", 33)
joe: Person = Person(Joe,Brighton,33)

fjavieralba

import java.io.IOException;
import java.util.Properties;
import kafka.server.KafkaConfig;
import kafka.server.KafkaServerStartable;
 
 
public class KafkaLocal {
 
	public KafkaServerStartable kafka;
	public ZooKeeperLocal zookeeper;

rgreenjr

-- show running queries (pre 9.2)
SELECT procpid, age(clock_timestamp(), query_start), usename, current_query 
FROM pg_stat_activity 
WHERE current_query != '<IDLE>' AND current_query NOT ILIKE '%pg_stat_activity%' 
ORDER BY query_start desc;

-- show running queries (9.2)
SELECT pid, age(clock_timestamp(), query_start), usename, query 
FROM pg_stat_activity 
WHERE query != '<IDLE>' AND query NOT ILIKE '%pg_stat_activity%'