Opportunity to grow

byMagda Żebrowska
January 25, 2023
4 minute read

In 2022, in addition to the work we do for our clients, we put our heads together and organized events and activities that would help us further develop our skills and knowledge, while providing a healthy break from our daily tasks. What follows is a brief account of what we planned, what worked and what didn’t.

Book Santa

We started the new year with gifts. Everyone could order a book, an actual physical book made of paper and ink, the only condition was that it be “at least a little work-related”. The idea was well received and orders soon poured in. The logistics involved in collecting titles from 130 people, ordering and then sending them to those who work more often remotely proved something of a challenge, but somehow we managed. Only one book from the UK got irretrievably stuck in customs (thanks, Brexit!). I don’t know how many books were read – since they were gifts, it didn’t seem appropriate to ask! – but I do know that one of them is currently being used as a monitor stand. An unexpectedly fascinating side effect of the scheme was being able to take a look at the freely available excel sheet and see who had ordered what and to learn about books you’d previously been unaware of.

Flashtalks

We meet once a month on a Friday to hear three people from the company, usually developers, give short presentations. Ensuring that every month there are enough volunteers willing to talk about something technical or somehow related to our work is no mean feat. Persuading, encouraging, twisting the arms of busy colleagues is a major challenge for the organizers of these talks. Occasionally, these talks cover less technical areas and we get the chance to learn about advantages of giving and receiving feedback, money saving and how to become a conference speaker. The purpose of Flashtalks is to both share knowledge and create a space where presentation skills can be practiced and honed in front of a larger audience. In 2022 there were 29 speakers (seven of whom spoke twice) and 36 presentations altogether. Topics ranged from “How to monitor applications after deployment” to “Will Niagara Files work on the Mississippi” and “DIY simple lab power supply”. Both novice developers as well as senior conference veterans share their wisdom. One of the great things about Flashtalks is the post-talk questionnaire, which always provides us with valuable feedback on what went well and what could be done better. Each Flashtalk ends with a quiz, which introduces an element of gamification and prevents Flashtalks from becoming merely a chance to take a break from work.

One of the aims of the Flashki is to create new conference speakers. This year Monika Fus made her debut at Confitura, an event very much close to our hearts, where she spoke about “L10n, i18n and t9n in the JVM world”. Other speakers included Piotr Fus with his presentation “How to get started with metrics”, Maciek Próchniak with “Well, it’s time to synchronize watches” and Dominik Przybysz with “OOP Revisited”. The whole team traveled around Poland and beyond with their presentations. Check them out here: https://touk.pl/talks/2022. While we had hoped there would be more newcomers in 2022, we are confident that 2023 will see a greater number of conference debuts.

Dojo

TouK Dojo is a more hands-on learning initiative that one of the developers came up with this year. We hold technical workshops for each other and meetings where we solve problems, often algorithmic. It’s a good opportunity to bounce ideas off each other about how to do things, try out tools, ask questions and work on real examples. Meetings usually take place once a week, live and online.

Blog

In April, as a grassroots initiative, a few of us set a goal to post monthly on our company blog. We wanted to restore it to its former glory, or perhaps just revive it after the drought years of the pandemic. We almost succeeded, with our combined efforts resulting in six posts about hackathons, a summary of the first post-pandemic Confitura, and of course some technical posts. We are now thinking about how to take the initiative further. It seems that the valuable content we could share is there, but we need to find the time and a way to overcome writer’s block.

Hackathons

Last year we organized a couple of hackathons: one in the spring and one in the autumn. We had initially considered having four in the space of a year, but that turned out to be a bit too ambitious, given the amount of work we do for our clients and the number of ideas to hack. The general framework developed in battle is: two days in our office, any project, any team composition, pizza and snacks for all. You can read detailed descriptions of what we achieved here: https://touk.pl/blog/2022/05/12/touk-hackathon-toukathon-april-2022/ and https://touk.pl/blog/2022/11/28/toukathon-october-2022/. In spring sixteen people coded together, in autumn eight.

Books

It has always been possible for any employee to order books for our shared library. Perhaps because of the number of books gifted at the start of the year, the number of books ordered during the year was a little smaller than normal. Still, our library has now been enriched with:

Diagnosing and Changing Organizational Culture: Based on the Competing Values Framework, Kim S. Cameron, Robert E. Quinn
The Enterprise Big Data Lake, Alex Gorelik
The Java Module System, Nicolai Parlog
Bulletproof TLS and PKI 2ed, Ivan Ristić
Job crafting nowa metoda budowania zaangażowania i poczucia sensu w pracy, Malwina Puchalska-Kamińska, Agnieszka Łądka- Barańska
Functional programming in Scala second edition, Paul Chiusano, Runar Bjarnason
Functional Design and Architecture v7, Alexander Granin
Functional Event-Driven Architecture, Gabriel Volpe
Code, Charles Petzold

Since January is time for resolutions, here are ours. This year we want to continue the Flashki (the first has already taken place on 20 January), we will confidently hack together, and we are already planning a calendar of speeches at conferences.

Magda Żebrowska

— Previous article

TouKathon – October 2022

Using WsLite in practice

byPiotr Jagielski
January 3, 2013

TL;DR

There is a example working GitHub project which covers unit testing and request/response logging when using WsLite.

Why Groovy WsLite ?

I’m a huge fan of Groovy WsLite project for calling SOAP web services. Yes, in a real world you have to deal with those - big companies have huge amount of “legacy” code and are crazy about homogeneous architecture - only SOAP, Java, Oracle, AIX…

But I also never been comfortable with XFire/CXF approach of web service client code generation. I wrote a bit about other posibilites in this post. With JAXB you can also experience some freaky classloading errors - as Tomek described on his blog. In a large commercial project the “the less code the better” principle is significant. And the code generated from XSD could look kinda ugly - especially more complicated structures like sequences, choices, anys etc.

Using WsLite with native Groovy concepts like XmlSlurper could be a great choice. But since it’s a dynamic approach you have to be really careful - write good unit tests and log requests. Below are my few hints for using WsLite in practice.

Unit testing

Suppose you have some invocation of WsLite SOAPClient (original WsLite example):

def getMothersDay(long _year) {
    def response = client.send(SOAPAction: action) {
       body {
           GetMothersDay('xmlns':'http://www.27seconds.com/Holidays/US/Dates/') {
              year(_year)
           }
       }
    }
    response.GetMothersDayResponse.GetMothersDayResult.text()
}

How can the unit test like? My suggestion is to mock SOAPClient and write a simple helper to test that builded XML is correct. Example using great SpockFramework:

void setup() {
   client = Mock(SOAPClient)
   service.client = client
}

def "should pass year to GetMothersDay and return date"() {
  given:
      def year = 2013
  when:
      def date = service.getMothersDay(year)
  then:
      1 * client.send(_, _) >> { Map params, Closure requestBuilder ->
            Document doc = buildAndParseXml(requestBuilder)
            assertXpathEvaluatesTo("$year", '//ns:GetMothersDay/ns:year', doc)
            return mockResponse(Responses.mothersDay)
      }
      date == "2013-05-12T00:00:00"
}

This uses a real cool feature of Spock - even when you mock the invocation with “any mark” (_), you are able to get actual arguments. So we can build XML that would be passed to SOAPClient's send method and check that specific XPaths are correct:

void setup() {
    engine = XMLUnit.newXpathEngine()
    engine.setNamespaceContext(new SimpleNamespaceContext(namespaces()))
}

protected Document buildAndParseXml(Closure xmlBuilder) {
    def writer = new StringWriter()
    def builder = new MarkupBuilder(writer)
    builder.xml(xmlBuilder)
    return XMLUnit.buildControlDocument(writer.toString())
}

protected void assertXpathEvaluatesTo(String expectedValue,
                                      String xpathExpression, Document doc) throws XpathException {
    Assert.assertEquals(expectedValue,
            engine.evaluate(xpathExpression, doc))
}

protected Map namespaces() {
    return [ns: 'http://www.27seconds.com/Holidays/US/Dates/']
}

The XMLUnit library is used just for XpathEngine, but it is much more powerful for comparing XML documents. The NamespaceContext is needed to use correct prefixes (e.g. ns:GetMothersDay) in your Xpath expressions.

Finally - the mock returns SOAPResponse instance filled with envelope parsed from some constant XML:

protected SOAPResponse mockResponse(String resp) {
    def envelope = new XmlSlurper().parseText(resp)
    new SOAPResponse(envelope: envelope)
}

Request and response logging

The WsLite itself doesn’t use any logging framework. We usually handle it by adding own sendWithLogging method:

private SOAPResponse sendWithLogging(String action, Closure cl) {
    SOAPResponse response = client.send(SOAPAction: action, cl)
    log(response?.httpRequest, response?.httpResponse)
    return response
}

private void log(HTTPRequest request, HTTPResponse response) {
    log.debug("HTTPRequest $request with content:\n${request?.contentAsString}")
    log.debug("HTTPResponse $response with content:\n${response?.contentAsString}")
}

This logs the actual request and response send through SOAPClient. But it logs only when invocation is successful and errors are much more interesting… So here goes withExceptionHandler method:

private SOAPResponse withExceptionHandler(Closure cl) {
    try {
        cl.call()
    } catch (SOAPFaultException soapEx) {
        log(soapEx.httpRequest, soapEx.httpResponse)
        def message = soapEx.hasFault() ? soapEx.fault.text() : soapEx.message
        throw new InfrastructureException(message)
    } catch (HTTPClientException httpEx) {
        log(httpEx.request, httpEx.response)
        throw new InfrastructureException(httpEx.message)
    }
}
def send(String action, Closure cl) {
    withExceptionHandler {
        sendWithLogging(action, cl)
    }
}

XmlSlurper gotchas

Working with XML document with XmlSlurper is generally great fun, but is some cases could introduce some problems. A trivial example is parsing an id with a number to Long value:

def id = Long.valueOf(edit.'@id' as String)

The Attribute class (which edit.'@id' evaluates to) can be converted to String using as operator, but converting to Long requires using valueOf.

The second example is a bit more complicated. Consider following XML fragment:

<edit id="3">
   <params>
      <param value="label1" name="label"/>
      <param value="2" name="param2"/>
   </params>
   <value>123</value>
</edit>
<edit id="6">
   <params>
      <param value="label2" name="label"/>
      <param value="2" name="param2"/>
   </params>
   <value>456</value>
</edit>

We want to find id of edit whose label is label1. The simplest solution seems to be:

def param = doc.edit.params.param.find { it['@value'] == 'label1' }
def edit = params.parent().parent()

But it doesn’t work! The parent method returns multiple edits, not only the one that is parent of given param…

Here’s the correct solution:

doc.edit.find { edit ->
    edit.params.param.find { it['@value'] == 'label1' }
}

Example

The example working project covering those hints could be found on GitHub.

DDevelopment & Design

All field constructor in Groovy

byDominik Przybysz
August 16, 2015

TupleConstructor annotation in Groovy generate constructors for class with each of its properties (eventually also fields). The class below@TupleConstructor(includeFields = true)class Person { String firstName String lastName&nb...