Author Archives: tobias

SQL LIKE operation in Cassandra, is possible in v3.4+

Posted on August 12, 2016 by tobias

For a long time it has not been possible to do a SELECT * FROM table WHERE firstname like ‘t%’; in Cassandra like you could in eg.. MySQL or any other Relation Database for that matter. In Cassandra v3.4 this … Continue reading →

Posted in Uncategorized | 3 Comments

UDF/User Defined Functions in Cassandra 3.x

Posted on August 11, 2016 by tobias

I was just playing around with Cassandra WRITETIME and thought it was somewhat difficult to figure out the date / timestamp of a number like this (microseconds since EPOC) 1470645914253000. So in my example it looked like this

cqlsh:bth> select id, writetime(dateofbirth) from bth.employee;

 id | writetime(dateofbirth)
----+------------------------
  1 |       1470645914253000
  2 |       1470645977177000
  7 |       1470948508799001
  3 |       1470645977178000

(4 rows)
cqlsh:bth>

cqlsh:bth> select id, writetime(dateofbirth) from bth.employee;

id | writetime(dateofbirth)

----+------------------------

1 | 1470645914253000

2 | 1470645977177000

7 | 1470948508799001

3 | 1470645977178000

(4 rows)

cqlsh:bth>

So … Continue reading →

Posted in Cassandra, JAVA | 1 Comment

Cassandra set the writetime explicitly with a PreparedStatement

Posted on March 16, 2016 by tobias

This is a quick one, I wanted to set the writetime of a row explicitly when I populate the database for testing purposes. We use the writetime of a column to filter them out. It required some looking around to … Continue reading →

Posted in Cassandra, JAVA, Scala | 1 Comment

Apache SPARK and Cassandra and SQL

Posted on January 21, 2016 by tobias

This is a short intro to start using Apache SPARK with Cassandra, running SQL on the Cassandra tables. Note that I am not running a SPARK cluster, I am running “local”, to me this is really convenient, not having to … Continue reading →

Posted in Uncategorized | Tagged apache, cassandra, cassandrasqlcontext, dependencies, exception, nosuchmethodexception, sbt, scala, spark, sql | 2 Comments

SBT Good to know…

Posted on November 5, 2015 by tobias

Dependecy problems I have been having some difficulties figuring out what depends on what. I found the following set plugins which I think can be really helpful; https://github.com/jrudolph/sbt-dependency-graph and https://github.com/gilt/sbt-dependency-graph-sugar Be sure to install GraphWiz first, I used Homebrew on … Continue reading →

Posted in SBT, Scala | 1 Comment

Create an MBean (JMX) in Scala

Posted on November 3, 2015 by tobias

Create the MBean like this

trait OrderTrackerMBean {
  def getOrderId : Int
  def setOrderId(orderId:Int)
}

class OrderTracker extends OrderTrackerMBean {
  var orderId = 0
  override def getOrderId: Int = orderId
  override def setOrderId(_orderId: Int)= {
    orderId = _orderId
  }

}

trait OrderTrackerMBean {

def getOrderId : Int

def setOrderId(orderId:Int)

}

class OrderTracker extends OrderTrackerMBean {

var orderId = 0

override def getOrderId: Int = orderId

override def setOrderId(_orderId: Int)= {

orderId = _orderId

}

NOTE, that the interface/trait must end with MBean in the name And this is how you register your MBean

package com.tsoft.playingWithLogback

import java.lang.management.ManagementFactory
import javax.management.{ObjectName, MBeanServer}

import org.slf4j.{MarkerFactory, Marker, LoggerFactory}
import org.slf4j.MDC
import scala.concurrent.{Await, Future}
import scala.concurrent.duration._
import scala.concurrent.ExecutionContext.Implicits.global

object LotsOfLogOutput {

  val logger = LoggerFactory.getLogger(this.getClass)

  val orderTrackerBean = new OrderTracker
  val mbs:MBeanServer = ManagementFactory.getPlatformMBeanServer();
  val mBeanName:ObjectName = new ObjectName("com.tsoft.playingWithLogback:type=Tracking");
  mbs.registerMBean( orderTrackerBean, mBeanName);

...

package com.tsoft.playingWithLogback

import java.lang.management.ManagementFactory

import javax.management.{ObjectName, MBeanServer}

import org.slf4j.{MarkerFactory, Marker, LoggerFactory}

import org.slf4j.MDC

import scala.concurrent.{Await, Future}

import scala.concurrent.duration._

import scala.concurrent.ExecutionContext.Implicits.global

object LotsOfLogOutput {

val logger = LoggerFactory.getLogger(this.getClass)

val orderTrackerBean = new OrderTracker

val mbs:MBeanServer = ManagementFactory.getPlatformMBeanServer();

val mBeanName:ObjectName = new ObjectName("com.tsoft.playingWithLogback:type=Tracking");

mbs.registerMBean( orderTrackerBean, mBeanName);

...

And the simply launch Java Mission Control (imc), attach to the JVM, and modify … Continue reading →

Posted in Uncategorized | 2 Comments

SBT module not found, why ?

Posted on November 3, 2015 by tobias

I have an build.sbt file that looks like this

name := "TobiasPlayground"

version := "1.0"

scalaVersion := "2.11.7"

scalacOptions := Seq("-unchecked", "-deprecation", "-encoding", "utf8")

libraryDependencies ++= {
  val akkaV = "2.3.9"
  val sprayV = "1.3.3"
  Seq(
    "io.spray"            %%  "spray-client"  % sprayV,
    "io.spray"            %%  "spray-can"     % sprayV,
    "io.spray"            %%  "spray-routing" % sprayV,
    "io.spray"            %%  "spray-testkit" % sprayV  % "test",
    "com.typesafe.akka"   %%  "akka-actor"    % akkaV,
    "com.typesafe.akka"   %%  "akka-testkit"  % akkaV   % "test",
    "org.specs2"          %%  "specs2-core"   % "2.3.11" % "test",
    "org.slf4j"           %%   "slf4j-api"      % "1.7.10"
  )
}

name := "TobiasPlayground"

version := "1.0"

scalaVersion := "2.11.7"

scalacOptions := Seq("-unchecked", "-deprecation", "-encoding", "utf8")

libraryDependencies ++= {

val akkaV = "2.3.9"

val sprayV = "1.3.3"

Seq(

"io.spray" %% "spray-client" % sprayV,

"io.spray" %% "spray-can" % sprayV,

"io.spray" %% "spray-routing" % sprayV,

"io.spray" %% "spray-testkit" % sprayV % "test",

"com.typesafe.akka" %% "akka-actor" % akkaV,

"com.typesafe.akka" %% "akka-testkit" % akkaV % "test",

"org.specs2" %% "specs2-core" % "2.3.11" % "test",

"org.slf4j" %% "slf4j-api" % "1.7.10"

)

}

But for some reason I can’t get slf4j downloaded from the Maven repository (http://mvnrepository.com) If I search the Maven Repository, I can clearly see that the version I intend to … Continue reading →

Posted in Uncategorized | Leave a comment

See who is connected to the same network / WIFI

Posted on October 11, 2015 by tobias

There are tools out there, such as Angry IP Scanner, iNet or IP Scanner, Â but this can easily be done using a bash script, not as nice looking perhaps but it does the job. The script :

#!/bin/bash
for i in {0..255}
do
	cmd="nslookup 192.168.1."
	cmd=$cmd$i
	result=$($cmd|egrep "Address|name")
	echo "****************"
	echo $cmd
	echo $result
done

#!/bin/bash

for i in {0..255}

cmd="nslookup 192.168.1."

cmd=$cmd$i

result=$($cmd|egrep "Address|name")

echo "****************"

echo $cmd

echo $result

done

Which should … Continue reading →

Posted in Uncategorized | 1 Comment

Övervakning av min IVT-490 värmepump med Raspberry Pi

Posted on March 8, 2015 by tobias

I denna artikeln ska jag försöka beskriva mitt lilla projekt med att övervaka min IVT-490 värmepump med en Raspberry P. Jag har hämtat mycket kunskap från dessa två forum-trådar : http://www.varmepumpsforum.com/vpforum/index.php?topic=27306.15Tanken och http://www.byggahus.se/forum/varme-allmant/44487-prata-med-ivt-490-a-5.html Min värmepump har ett interface som ser … Continue reading →

Posted in Raspberry Pi | 33 Comments

Calculate the minimum waste when cutting planks…

Posted on July 10, 2014 by tobias

I made a web application which will calculate the most optimum layout of your pieces you would like to cut from a plank. This helps in figuring out how many planks of a certain size you would have to buy, … Continue reading →

Posted in optimization, tool, web | Leave a comment

Author Archives: tobias

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