devsprint

object portfolio {

  /**
   * EXERCISE 1
   *
   * Using only sealed traits and case classes, develop a model of a stock
   * exchange. Ensure there exist values for NASDAQ and NYSE.
   */
  sealed trait Exchange
  object Exchange {

devsprint

Advanced Functional Programming with Scala - Notes

Copyright © 2017 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

devsprint

object ServerSparkContext {

  private[this] lazy val _sqlContext = {
    val conf = new SparkConf()
      .setAppName("....")
    val sc = new SparkContext(conf)

    // TODO: Bug in Spark: http://stackoverflow.com/questions/30323212
    val ctx = new HiveContext(sc)
    ctx.setConf("spark.sql.hive.convertMetastoreParquet", "false")

devsprint

#!/bin/bash

# git client wrapper to be used with wowapp gitlab
git config  user.name "Gabriel Ciuloaica"
git config  user.email [email protected]
git "$@"

devsprint

import spray.json._
import spray.http.HttpBody
import spray.httpx.marshalling._
import spray.httpx.unmarshalling._
import spray.http.MediaTypes._
import spray.routing.directives._
import spray.routing._
import spray.http._
import spray.json.DefaultJsonProtocol
import spray.httpx.SprayJsonSupport

devsprint

Introduction to Kafka

Kafka acts as a kind of write-ahead log (WAL) that records messages to a persistent store (disk) and allows subscribers to read and apply these changes to their own stores in a system appropriate time-frame.

Terminology:

• Producers send messages to brokers
• Consumers read messages from brokers
• Messages are sent to a topic

devsprint

package net.devsprint.reactive.cassandra;

import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;

import rx.Observable;

import com.datastax.driver.core.ResultSet;
import com.datastax.driver.core.Session;

devsprint

package net.devsprint.reactive.cassandra;

import java.util.concurrent.ExecutorService;

import rx.Observable;
import rx.Observer;
import rx.Subscription;
import rx.subscriptions.Subscriptions;

import com.datastax.driver.core.ResultSet;

devsprint

slow

This bash script offers quick shortcuts to simulate slower network connections. It is useful when you need to simulate a wireless network on a Linux network server, especially when you are using a virtual machine guest on your local machine or in the cloud.

slow 3G                   # Slow network on default eth0 down to 3G wireless speeds
slow reset                # Reset connection for default eth0 to normal
slow vsat --latency=500ms # Simulate satellite internet  with a high latency
slow dsl -b 1mbps         # Simulate DSL with a slower speed than the default

slow modem-56k -d eth0 # Simulate a 56k modem on the eth1 device. eth0 is unchanged.

devsprint

private static String WRITE_STATEMENT = "INSERT INTO avatars (id, image_type, avatar) VALUES (?,?,?);";

private final BoundStatement writeStatement=writeStatement = session.prepare(WRITE_STATEMENT)
				.setConsistencyLevel(ConsistencyLevel.LOCAL_QUORUM).bind();
try {
  		BoundStatement stmt = driver.getWriteStatement();
			stmt.enableTracing();
			stmt.setLong("id", accountId);
			stmt.setString("image_type", image.getType());
			stmt.setBytes("avatar", ByteBuffer.wrap(image.getBytes()));