Blog

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Apr 3, 2021, 8:03 PM
In this article we continue our research on how to implement field level text search by creating a companion translations table for each class. We'll use GIN / GiST indexes which ware described in the opening article of this series and we'll try to implement the described concept using Spring Data JPA, Hibernate and Postgres.
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Sep 27, 2020, 1:00 PM
Software systems that operate in an international environment often must support multilingual data models. For example, users of a procurement system must be able to describe the products they want to buy in many languages because they want to receive offers from suppliers that reside in different countries. Designing a system that can effectively display data in a given users language and also allow him to do full text searches is a challenge - many commonly used patterns will have a high performance penalty and slow down your system. In this first of a series of articles we will describe how Postgres supports full text search in general and what are the most common anti-patterns for multilingual SQL models.
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Oct 21, 2019, 11:42 AM
The times when Java was available on almost every desktop are long gone but you can still distribute your desktop applications written in Java in a user friendly way. Since the release of OpenJDK and OpenJFX 9 we can benefit from the JVMs modularization efforts and easily build executables with a bundled JVM trimmed to the needs of our application. In this article we will show you how we ported our small desktop app called PDF Decorator initially to OpenJDK 11 and used tools like jlink and jpackage to start distributing our app without requiring any third party software on our clients machines.
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Jun 22, 2019, 10:13 AM
Problem: we want queries to our entities to eagerly fetch only the fields that we need in the given context (for example to show in a specific UI data table). Requirement: our solution must be able to accept dynamic filter compositions. Possible solutions: Named Entity Graphs from the JPA standard or Projections mechanism from Spring Data. Lets research them!
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Feb 8, 2018, 12:12 PM
In the past months we could hear many controversies surrounding an upcoming coin developed by FutureNet called FuturoCoin. FutureNet is a social network and Multi Level Marketing (MLM) platform. Most of the cryto-community didn't take them seriously and ware expecting another DasCoin - a coin which had little do to with the term 'cryptocurrency' but was heavily marketed as such using MLM. Both FutureNet and the creators of DasCoin (Netleaders) are under investigation by the Polish government under the suspicion of being a ponzi-scheme. The fact that FutureNet promoted their FuturoCoin without even publishing a whitepaper also didn't help. Now that they finally have one and also published their source code we can see what this coin really is.
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Nov 1, 2017, 10:00 AM
If you're interested in Bitcoin, Ethereum, etc. then you're probably tempted by ads with mining equipment or cloud mining contracts. Many of them promise you substantial passive profits and a fast return of investment under one year. Can it really be this easy? Here at WALCZAK.IT we experiment heavily with cryptocurrencies and we've also build our behemoth of a rig which mines three totally different coins at once. We've experienced firsthand that cryptocurrency mining is not trivial, nor is it passive or risk-free. Here are some cons you should consider before investing into it.
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Oct 4, 2017, 10:13 PM
For the past few moths we've been developing our own simulation and notification system that aids us in cryptocurrency trading. As a byproduct of this enterprise we maintain a huge database of trades, exchange rates and OHLC data imported from many exchanges. We decided that it would be a shame to just keep this in-house so we're lunching a new polish website - kryptowalutownia.pl - on which you can view aggregated price charts and compare exchange rates from multiple exchanges.
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Sep 15, 2017, 7:06 PM
If you own Ethereum mining rigs with RX 470 / 480 / 570 / 580 AMD graphic cards you might have noticed that your hashrates have been slightly going down. In our RX 470 rig we went down from 27-28 MH/s per card to 25-26 MH/s. This drop will continue if you do nothing about it as the DAG file is slowly overwhelming your cards capabilities. Luckily AMD has been working on this problem.
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Aug 14, 2017, 2:47 PM
WordPress, Joomla and Drupal are still the most popular content management systems on the web but should you use them for your next project? All of them claim to have a good visual WYSIWYG page editor but once you see Concrete5 in action you'll realize how website editing should really look like. Lets compare.
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Nov 26, 2013, 6:53 PM
The first copies of our book "OPEN SOURCE projects – how are they organized and financed" saw daylight in the year 2011. It’s hard to believe that so many time has passed since its first release.