StackOverflow2013

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copied!<p>After inspecting the history of that line, my main conclusion is that there has been some incompetent programming at work.</p> <ol> <li><p>That line is gratuitously convoluted. The general form</p> <pre><code>a? true : b </code></pre> <p>for <code>boolean a, b</code> is equivalent to the simple</p> <pre><code>a || b </code></pre></li> <li><p>The surrounding negation and excessive parentheses convolute things further. Keeping in mind <a href="http://en.wikipedia.org/wiki/De_Morgan%27s_laws">De Morgan's laws</a> it is a trivial observation that this piece of code amounts to</p> <pre><code>if (!_ok && Math.random() <= 0.1) return res; </code></pre></li> <li><p>The commit that <a href="https://github.com/mongodb/mongo-java-driver/commit/ee7543a4f7cc26618cf78eab2a18bd33b3e101cc">originally introduced this logic</a> had</p> <pre><code>if (_ok == true) { _logger.log( Level.WARNING , "Server seen down: " + _addr, e ); } else if (Math.random() < 0.1) { _logger.log( Level.WARNING , "Server seen down: " + _addr ); } </code></pre> <p>—another example of incompetent coding, but notice the <em>reversed logic</em>: here the event is logged if either <code>_ok</code> or in 10% of other cases, whereas the code in 2. <em>returns</em> 10% of the times and logs 90% of the times. So the later commit ruined not only clarity, but correctness itself. </p> <p>I think in the code you have posted we can actually see how the author intended to transform the original <code>if-then</code> somehow literally into its negation required for the early <code>return</code> condition. But then he messed up and inserted an effective "double negative" by reversing the inequality sign.</p></li> <li><p>Coding style issues aside, stochastic logging is quite a dubious practice all by itself, especially since the log entry does not document its own peculiar behavior. The intention is, obviously, reducing restatements of the same fact: that the server is currently down. The appropriate solution is to log only <em>changes</em> of the server state, and not each its observation, let alone a random selection of 10% such observations. Yes, that takes just a little bit more effort, so let's see some.</p></li> </ol> <p>I can only hope that all this evidence of incompetence, accumulated from inspecting <em>just three lines of code</em>, does not speak fairly of the project as a whole, and that this piece of work will be cleaned up ASAP.</p>

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