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Akka FAQ

1. Constructor vs preStart() - Is it ok to create child actors in the constructor vs doing it in preStart() ?

Both the constructor and preStart() are called during a restart. So it's absolutely fine to created child actors in the constructor. (Aside: when using preStart() always call super.preStart() first). If for some reason you don't want to create children during restart then use preStart() for creating and make sure you overrride preRestart()

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package org.uarun.typeclasses

object Main extends ToDoubleOps {
  def main(args: Array[String]) {
    val x = 100
    println(s"$x doubled is ${x.doubled}")
  }
}

trait DoubleOps[A] {

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#!/bin/sh

user=$1
if [ -z "$user" ]; then
    user=liquidnt
fi

displayNum=`echo $DISPLAY | sed -e 's/^.*://' -e 's/\.[0123456789]*//'`
echo "Display # = $displayNum"
cookie=`xauth list | grep ":$displayNum"`

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DBQuery.prototype._prettyShell = true

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Intellij IDEA - Cheat Sheet (aka most useful shortcuts)

Note: Some of these keymapping are specific to IdeaVim plugin. If you don't use IdeaVim (what' wrong with you :)), I've tried to point out where they differ, but I could have missed a few

Coding Session

Parameter documentation for Method Calls

• Ctrl-P - Popup parameter documentation for method calls

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apply plugin: 'java'
apply plugin: 'scala'
// For those using Eclipse or IntelliJ IDEA
apply plugin: 'eclipse'
apply plugin: 'idea'

def findPlay20(){
  def pathEnvName = ['PATH', 'Path'].find{ System.getenv()[it] != null }
  for(path in System.getenv()[pathEnvName].split(File.pathSeparator)){
    for(playExec in ['play.bat', 'play.sh', 'play']){

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Resolving Version Conflicts in Gradle

If one module has a dependency on version 1.1 of library X and another module on version 2.0 of the same library, gradle will use the latest version.

Failing a build on version conflict

To make gradle fail the build on encountering a conflict, we can do the following:

configurations.all {

resolutionStrategy {

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Useful Scalac Options

-encoding "UTF-8"

-target:jvm-1.6

Uses the ASM Compiler backend to generate bytecode (Scala 2.10)

-deprecation

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import org.apache.ivy.util.url.CredentialsStore

CredentialsStore.INSTANCE.addCredentials(
    nexusRealm,
    nexusHost,
    nexusUserName,
    nexusPassword
)

/* Example *

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Zsh Tips and Tricks

Argument History

!*        # ... All parameters of the last command
!$        # ... Last parameter of the last command
!^        # ... First parameter of the last command
!:1       # ... First parameter of the last command

!-2:2 # ... Second parameter from 2 commands ago