Bob Martin’s eliminate boolean arguments tip – an example

I don’t always agree with Bob Martin’s Clean Code Tip #12: Eliminate Boolean Arguments – probably because the mathematician in me believes that there are such things as functions of a boolean value – but I came across an example in a WinForms app today where I’d apply it.

void FindApplicant(int id)
{
    processUIChange(true);
    applicant= getTheApplicantFromDataLayer(id);
    processUIChange(false);
}

turned out to mean:

void ProcessUI(bool processing)
{
    if(processing)
    {
      this.Enabled=false;  
    }
    else
    {
       ... do a whole load of stuff
    }
}

which would have been easier to read as:

void FindApplicant(int id)
{
    DisableUIWhileUpdating();
    applicant= getTheApplicantFromDataLayer(id);
    UpdateUIAfterDataChange();
}

void DisableUIWhileUpdating()
{
    this.Enabled=false
}
void UpdateUIafterDataChange()
{
    ...do a whole load of stuff
}

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