Oct 7, 2015 - 1 minute read - Comments - tipgotchajavacharacter-encodingutf8java-tool-optionsfile-encoding
Make the JVM use UTF-8 character encoding by default
Set up the system property JAVA_TOOL_OPTIONS to -Dfile.encoding=UTF8
Oct 5, 2015 - 1 minute read - Comments - protiptipmaventestskip-testsmaven-test-skip
There are times when you only want to have the production code:
For that, maven allows to skip the tests, selectively:
-DskipTests compiles the tests, but skips running them-Dmaven.test.skip skips compiling the tests and does not run them. This can also be written as -Dmaven.test.skip=trueIn case some of your tests depend on tests from another artifact (e.g. Object Mother, test infrastructure) and the latter has changed, you must compile the tests. You need to not execute the tests
For more information:
Oct 2, 2015 - 2 minute read - Comments - tipbashpipefailureexit-codeexit-statuscodefeature-toggle
In bash, the usual behavior is to return the last status code:
bash-3.1$ tr
tr: two strings must be given when translating
bash-3.1$ echo $?
1
But this also applies to pipes:
bash-3.1$ tr|tee 1.txt
tr: two strings must be given when translating
bash-3.1$ echo $?
0
Should you want to pass the non-zero (error) status code to the next operation, use this feature toggle: set -o pipefail
bash-3.1$ set -o pipefail
bash-3.1$ tr|tee 1.txt
tr: two strings must be given when translating
bash-3.1$ echo $?
1
This might be useful if you stop on a non-zero status (set -e).
Reference from the Set Builtin:
-e
Exit immediately if a pipeline (see Pipelines), which may consist of a single simple command (see Simple Commands), a list (see Lists), or a compound command (see Compound Commands) returns a non-zero status. The shell does not exit if the command that fails is part of the command list immediately following a while or until keyword, part of the test in an if statement, part of any command executed in a && or || list except the command following the final && or ||, any command in a pipeline but the last, or if the command’s return status is being inverted with !. If a compound command other than a subshell returns a non-zero status because a command failed while -e was being ignored, the shell does not exit. A trap on ERR, if set, is executed before the shell exits.
This option applies to the shell environment and each subshell environment separately (see Command Execution Environment), and may cause subshells to exit before executing all the commands in the subshell.
If a compound command or shell function executes in a context where -e is being ignored, none of the commands executed within the compound command or function body will be affected by the -e setting, even if -e is set and a command returns a failure status. If a compound command or shell function sets -e while executing in a context where -e is ignored, that setting will not have any effect until the compound command or the command containing the function call completes.
-o pipefail
If set, the return value of a pipeline is the value of the last (rightmost) command to exit with a non-zero status, or zero if all commands in the pipeline exit successfully. This option is disabled by default.
Oct 1, 2015 - 5 minute read - Comments - self-study-aggregationoctober2015read1986abstract-syntax-treeacidagileagile-academyalex-smithandrew-stewartarrayblockingqueueastbacklogbenchmarkbrett-l.-schuchertclassloaderclojurecode=datacommitmentcomparisonconcurrencyconcurrentlinkedqueuecontentioncost-reductiondata-structuredata=codedave-farleydependency-inversion-principledesign-principledipdisruptordocument-storedomdomain-specific-languagedoug-leadownsideelmevan-czaplickiexampleextreme-programmingframeworkfunctiongregory-brownhaskellhirotaka-takeuchihomoiconicityikujiro-nonakaintroductionjames-donelanjavajevgeny-kabanovjsonlambda-calculuslean-startuplmaxlow-costlow-level-optimizationmacromanagementmartin-thompsonmatt-mightmichael-barkermongodbmvpnikolaos-raptisobject-orientedoptimizationpair-programmingpaperparallelismpatricia-geepet-projectpostgresqlprinciplepriorityproduct-developmentproofproof-of-conceptracketring-bufferrobert-martinscriptscrumside-projectsoftware-qualitysolidspeedsprintstar-videosstephen-wolframsven-slootwegtddtrisha-geeturing-machineuniversal-turing-machinevideovirtual-domwhite-paperxp
I’ve read this article explaining how Elm works in relation to the virtual DOM. By Evan Czaplicki.
Tags: elm, dom, virtual-dom, comparison, speed, haskell, evan-czaplicki
I’ve read this article stating the downsides of using MongoDB. Written by Sven Slootweg
Tags: mongodb, downside, sven-slootweg, json, document-store, postgresql, acid
I’ve watched this video by Jevgeny Kabanov on classloaders: what they are, how they work nad some tips to solve common issues.
My notes:
There is also this article on the same video
Tags: jevgeny-kabanov, classloader, java,
I’ve read the wikipedia article about the truth table and the 16 possible binary boolean operators:
I’ve read this article by Matt Might about the benefits of implementing a language (from scratch but on top of another existing language used as framework). Chooses lambda calculus as the desired DSL
Tags: matt-might, lambda-calculus, racket, domain-specific-language
I’ve read this wikipedia article (both main and discussion) about this subject.
It has sounded strange to me the reference to S-expressions:
Data languages The notion of Turing-completeness does not apply to languages such as XML, HTML, JSON, YAML and S-expressions because they are typically used to represent structured data, not describe computation […]
If data (S-expression) is represented as the same format as code (e.g., Lisp’s S-expression) and the latter is used to represent a computation, shouldn’t be “data languages that also are used as computation languages” excluded from that list?
As a side note, Lisp is Turing Complete (see Turing Complete#Examples)
I’ve read this article by Stephen Wolfram about the proof of a Turing Machine 2,3 being universal by Alex Smith.
Tags: stephen-wolfram, turing-machine, universal-turing-machine, proof, paper, alex-smith
I’ve read this article by Nikolaos Raptis on committing to work in each sprint.
Tags: nikolaos-raptis, sprint, agile, commitment
I’ve read this stackoverflow question about the lack of post-increment operator (i++) in Ruby:
++ and – are NOT reserved operator in Ruby.
Mailing list from Yukihiro Matsumoto aka matz
I’ve read this article by James Donelan on the equivalence of code and data in homoiconic languages, including Clojure.
The article talks about homoiconicity, manually creating Abstract Syntax Trees (AST) out of data and the macro environment. Also, compares the difference between macros and functions.
Tags: code=data, data=code, james-donelan, clojure, homoiconicity, abstract-syntax-tree, ast, macro, function
I’ve watched this video introducing TDD by the Agile Academy. Explains its motivations and the basic cyclical fashion.
Tags: agile-academy, video, tdd, introduction
I’ve watched this video by Agile Academy on practicing pair programming. Explains the destination and how to get there.
Tags: agile-academy, pair-programming, video, introduction
I’ve read this article by Gregory Brown on how to apply the MVP and Lean Startup principles to side projects (a.k.a. pet projects). Try to start with a brainstorming session of all the features you want your product to have, then prioritise, picking the most important ones.
Most projects' needs can be solved with a minimal version, in the form of a script that took half an hour to develop.
Tags: gregory-brown, mvp, lean-startup, script, proof-of-concept, priority, backlog, side-project, pet-project, low-cost, cost-reduction
I’ve watched this video by STAR Videos on the basic principles behind Extreme Programming and how to use it to improve software quality
Tags: star-videos, extreme-programming, xp, software-quality
I’ve read this white paper describing the disruptor framework: a way of exchanging data between concurrent threads.
It uses a ring buffer and other techniques to eliminate write contention, reduce read contention and produces good results. It was developed for a financial exchange environment but it’s general purpose.
Tags: martin-thompson, dave-farley, michael-barker, patricia-gee, andrew-stewart, trisha-gee, disruptor, contention, framework, concurrency, parallelism, white-paper, comparison, arrayblockingqueue, concurrentlinkedqueue, doug-lea, benchmark, lmax, low-level-optimization, optimization
I’ve read this article about the ring buffer data structure. A FIFO data structure where elements get overwritten to reduce pressure on the garbage collector. Every message gets sent to every consumer.
Tags: patricia-gee, trisha-gee, disruptor, ring-buffer, data-structure
I’ve read this paper about the Dependency Inversion Principle (DIP) written Robert C. Martin.
It explains the theory, philosophy behind it. Also, creates an example with a copy buffer and different output locations
Tags: robert-martin, dependency-inversion-principle, dip, example, comparison, object-oriented, principle, solid, design-principle
I’ve read this article about the Dependency Inversion Principle (DIP) written by Brett L. Schuchert.
It is explained non-canonical representations of this principle, how in other cases he has solved it and conclusions of using it day to day.
Tags: brett-l.-schuchert, dependency-inversion-principle, dip, example, object-oriented, solid, design-principle
I’ve read this paper about the holistic approach to product development, considered seminal for Scrum and other Agile methodologies. Written by Hirotaka Takeuchi and Ikujiro Nonaka
In it, they describe how teams are distributed, the responsibilities for each one, and the degrees of freedom.
Cites the six basic characteristics:
Tags: hirotaka-takeuchi, ikujiro-nonaka, scrum, agile, product-development, management, 1986
Sep 30, 2015 - 1 minute read - Comments - bookreading2015Q3self-study
Books I’ve read this quarter1:
Books started, not yet finished (WIP):
Books I want to finish:
Books that have entered the queue:
The ending date of the quarter is the same as the publication date ↩︎
Sep 23, 2015 - 1 minute read - Comments - brown-bagtrainingclientclojurehomoiconicityprepared-katalispcode=datadata=codefeedback
Today, at a client, I’ve facilitated the brown-bag session on Clojure, introducing Lisp’s homoiconicity.
The session was designed as a kata, first introducing participants in the problem, letting some time to read the initial version and to think about possible solutions.
Then, I structured the rest of the time as a prepared kata, where I was explaining in the beamer our current problems (day-to-day tasks) and possible solutions in Clojure.
Among them:
I explained, in private to those who asked, about Lisp and its dialects Common Lisp, Clojure and Scheme.