<?xml version="1.0" encoding="utf-8" standalone="yes"?><rss version="2.0" xmlns:atom="http://www.w3.org/2005/Atom"><channel><title>Groovy on Bitecode blog</title><link>https://bitecode.blog/categories/groovy/</link><description>Recent content in Groovy on Bitecode blog</description><generator>Hugo</generator><language>en-us</language><lastBuildDate>Fri, 19 Aug 2016 00:00:00 +0000</lastBuildDate><atom:link href="https://bitecode.blog/categories/groovy/index.xml" rel="self" type="application/rss+xml"/><item><title>Between null and positive infinity</title><link>https://bitecode.blog/2016/08/19/groovy-compare-null/</link><pubDate>Fri, 19 Aug 2016 00:00:00 +0000</pubDate><guid>https://bitecode.blog/2016/08/19/groovy-compare-null/</guid><description>&lt;h2 id="problem"&gt;Problem&lt;/h2&gt;
&lt;p&gt;I happen to create a construction like this:&lt;/p&gt;
&lt;div class="highlight"&gt;&lt;pre tabindex="0" style="color:#f8f8f2;background-color:#282a36;-moz-tab-size:4;-o-tab-size:4;tab-size:4;"&gt;&lt;code class="language-groovy" data-lang="groovy"&gt;&lt;span style="display:flex;"&gt;&lt;span&gt;&lt;span style="color:#ff79c6"&gt;if&lt;/span&gt;&lt;span style="color:#ff79c6"&gt;(&lt;/span&gt;object&lt;span style="color:#ff79c6"&gt;?.&lt;/span&gt;&lt;span style="color:#50fa7b"&gt;value&lt;/span&gt; &lt;span style="color:#ff79c6"&gt;&amp;gt;&lt;/span&gt; &lt;span style="color:#bd93f9"&gt;0&lt;/span&gt;&lt;span style="color:#ff79c6"&gt;)&lt;/span&gt; &lt;span style="color:#ff79c6"&gt;{&lt;/span&gt;
&lt;/span&gt;&lt;/span&gt;&lt;span style="display:flex;"&gt;&lt;span&gt; println &lt;span style="color:#f1fa8c"&gt;&amp;#34;do something&amp;#34;&lt;/span&gt;
&lt;/span&gt;&lt;/span&gt;&lt;span style="display:flex;"&gt;&lt;span&gt;&lt;span style="color:#ff79c6"&gt;}&lt;/span&gt; &lt;span style="color:#ff79c6"&gt;else&lt;/span&gt; &lt;span style="color:#ff79c6"&gt;{&lt;/span&gt;
&lt;/span&gt;&lt;/span&gt;&lt;span style="display:flex;"&gt;&lt;span&gt; println &lt;span style="color:#f1fa8c"&gt;&amp;#34;do nothing&amp;#34;&lt;/span&gt;
&lt;/span&gt;&lt;/span&gt;&lt;span style="display:flex;"&gt;&lt;span&gt;&lt;span style="color:#ff79c6"&gt;}&lt;/span&gt;
&lt;/span&gt;&lt;/span&gt;&lt;/code&gt;&lt;/pre&gt;&lt;/div&gt;&lt;p&gt;Are you sure what will be printed when object is null?
I must say I wasn’t.&lt;/p&gt;
&lt;p&gt;We got used to negate null in groovy like this:&lt;/p&gt;
&lt;div class="highlight"&gt;&lt;pre tabindex="0" style="color:#f8f8f2;background-color:#282a36;-moz-tab-size:4;-o-tab-size:4;tab-size:4;"&gt;&lt;code class="language-groovy" data-lang="groovy"&gt;&lt;span style="display:flex;"&gt;&lt;span&gt;&lt;span style="color:#ff79c6"&gt;assert&lt;/span&gt; &lt;span style="color:#ff79c6"&gt;!&lt;/span&gt;&lt;span style="color:#ff79c6"&gt;null&lt;/span&gt; &lt;span style="color:#ff79c6"&gt;==&lt;/span&gt; &lt;span style="color:#ff79c6"&gt;true&lt;/span&gt; 
&lt;/span&gt;&lt;/span&gt;&lt;/code&gt;&lt;/pre&gt;&lt;/div&gt;&lt;p&gt;but what about using null with relation operator?&lt;/p&gt;
&lt;h2 id="comparing-null"&gt;Comparing null&lt;/h2&gt;
&lt;p&gt;Let us review below code:&lt;/p&gt;
&lt;div class="highlight"&gt;&lt;pre tabindex="0" style="color:#f8f8f2;background-color:#282a36;-moz-tab-size:4;-o-tab-size:4;tab-size:4;"&gt;&lt;code class="language-groovy" data-lang="groovy"&gt;&lt;span style="display:flex;"&gt;&lt;span&gt;&lt;span style="color:#ff79c6"&gt;assert&lt;/span&gt; &lt;span style="color:#ff79c6"&gt;null&lt;/span&gt; &lt;span style="color:#ff79c6"&gt;&amp;lt;&lt;/span&gt; &lt;span style="color:#bd93f9"&gt;0&lt;/span&gt;
&lt;/span&gt;&lt;/span&gt;&lt;span style="display:flex;"&gt;&lt;span&gt;
&lt;/span&gt;&lt;/span&gt;&lt;span style="display:flex;"&gt;&lt;span&gt;&lt;span style="color:#ff79c6"&gt;assert&lt;/span&gt; &lt;span style="color:#ff79c6"&gt;null&lt;/span&gt; &lt;span style="color:#ff79c6"&gt;&amp;lt;&lt;/span&gt; Integer&lt;span style="color:#ff79c6"&gt;.&lt;/span&gt;&lt;span style="color:#50fa7b"&gt;MIN_VALUE&lt;/span&gt;
&lt;/span&gt;&lt;/span&gt;&lt;span style="display:flex;"&gt;&lt;span&gt;&lt;span style="color:#ff79c6"&gt;assert&lt;/span&gt; &lt;span style="color:#ff79c6"&gt;null&lt;/span&gt; &lt;span style="color:#ff79c6"&gt;&amp;lt;&lt;/span&gt; Double&lt;span style="color:#ff79c6"&gt;.&lt;/span&gt;&lt;span style="color:#50fa7b"&gt;NEGATIVE_INFINITY&lt;/span&gt;
&lt;/span&gt;&lt;/span&gt;&lt;span style="display:flex;"&gt;&lt;span&gt;
&lt;/span&gt;&lt;/span&gt;&lt;span style="display:flex;"&gt;&lt;span&gt;&lt;span style="color:#ff79c6"&gt;assert&lt;/span&gt; &lt;span style="color:#ff79c6"&gt;null&lt;/span&gt; &lt;span style="color:#ff79c6"&gt;&amp;lt;&lt;/span&gt; Integer&lt;span style="color:#ff79c6"&gt;.&lt;/span&gt;&lt;span style="color:#50fa7b"&gt;MAX_VALUE&lt;/span&gt;
&lt;/span&gt;&lt;/span&gt;&lt;span style="display:flex;"&gt;&lt;span&gt;&lt;span style="color:#ff79c6"&gt;assert&lt;/span&gt; &lt;span style="color:#ff79c6"&gt;null&lt;/span&gt; &lt;span style="color:#ff79c6"&gt;&amp;lt;&lt;/span&gt; Double&lt;span style="color:#ff79c6"&gt;.&lt;/span&gt;&lt;span style="color:#50fa7b"&gt;POSITIVE_INFINITY&lt;/span&gt;
&lt;/span&gt;&lt;/span&gt;&lt;/code&gt;&lt;/pre&gt;&lt;/div&gt;&lt;p&gt;In each of these cases, the assertion passes without errors. This behavior might seem counterintuitive at first glance.&lt;/p&gt;</description></item></channel></rss>