Strange, I cannot comment my merge request.
I replaced the tabs by spaces as required.
Mike, thanks for your quick feedback. When you say that the refactoring
is an improvement, what does it improve for you?
Also, when you say that "Interface complexity is the #1 menace.", I
guess you are talking about the number of widgets that can compose a
user interface, the difficulty to use user interfaces?
Cheers,
Arno
Le 22/12/2016 à 11:15, Arnaud Blouin a écrit :
> Hi all,
>
> We are researchers in software engineering that currently work on user
> interface (UI) bad coding practices. We are studying UI listeners, in
> particular listeners that manage several widgets, like the following
> listener extracted from Freecol:
>
> public void actionPerformed(ActionEvent ae) {
> final String command = ae.getActionCommand();
> EuropeAction act = EuropeAction.valueOf(command);
> switch (act) {
> case EXIT:
> exitAction();
> break;
> case PURCHASE:
> getGUI().showPurchasePanel();
> break;
> case RECRUIT:
> getGUI().showRecruitPanel();
> break;
> case SAIL:
> sailAction();
> break;
> case TRAIN:
> getGUI().showTrainPanel();
> break;
> case UNLOAD:
> unloadAction();
> break;
> default:
> super.actionPerformed(ae);
> break;
> }
> }
>
> In such listeners, the source widget is identified using if/switch
> statements. Thanks to empirical studies we have indications that such a
> practice has a negative impact on the code quality. We call UI listeners
> that control three or more widgets, Blob Listeners (see this PDF
> document for more details: https://hal.inria.fr/hal-01308625v2/document).
>
> We identified in Freecol 15 instances of the Blob listener and for seven
> of them we have a refactoring solution. The merge request we just
> submitted (https://sourceforge.net/p/freecol/git/merge-requests/41/)
> removes these seven Blob listeners by splitting them into atomic UI
> listeners (i.e. they manage a single widget). Each commit of this
> request refers to one Blob listener. The new code is less complex in
> terms of cyclomatic complexity (CC) and lines of code (LoC): the new
> code has -122 LoCs and -36 of CC on the refactored files (according to
> Sonar analyses).
> Several details about the refactoring are described below.
>
>
> Complementary to this merge request, we have several questions for the
> Freecol's developers:
>
> 1/ Do you think that coding UI listeners that manage several widgets is
> a bad coding practice?
>
>
> 2/ Do you think that the threshold of three or more widgets per listener
> relevant for characterising a Blob listener?
>
>
> 3/ Do you consider the refactored code suitable for removing Blob listeners?
>
>
> 4/ Do you have any idea of the reason of the presence of Blob listeners
> in the code?
> For example, lack of anonymous functions (aka lambdas) in Java 7 (and
> previous JDKs)? Lack of programming experience at the early stage of the
> development? etc.
>
> 5/ Do you have suggestions about other bad user interface coding
> practices? This can concern controllers, commands, GUIs, widgets, data
> bindings, GUI testing, etc.
>
>
>
> Regarding the refactoring, FreeColPanel defines a button OK and an
> actionPerformed to manage it. Most of the FreeColPanel's children
> override the behaviour of this button OK (e.g. TradeRoutePanel). This
> explains why our refactoring did not always remove the actionPerformed
> methods to let the management of the button OK as it.
>
> Possible issue:
> src/net/sf/freecol/client/gui/panel/report/ReportPanel.java
> (actionPerformed, l140): we cannot find the associated widgets that will
> trigger the execution of the code lines 145-150.
>
> We identified 8 Blob listener for which we do not have a refactoring
> solution, for example:
> src/net/sf/freecol/client/gui/label/UnitLabel.java (actionPerformed,
> line 394): the listener registrations are made in QuickActionMenu, so we
> prefer not to refactor this Blob.
>
>
> Do not hesitate to discuss about the refactoring and provide me feedback.
>
> -- Arno
>
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