{"id":786,"date":"2014-07-02T19:24:10","date_gmt":"2014-07-03T02:24:10","guid":{"rendered":"https:\/\/blogs.plm.automation.siemens.com\/t5\/Polarion-Blog\/Tech-Tips-amp-Tricks-tips-to-solve-unruly-Velocity-problems\/ba-p\/380864"},"modified":"2026-03-26T05:30:57","modified_gmt":"2026-03-26T09:30:57","slug":"tech-tips-tricks-tips-to-solve-unruly-velocity-problems","status":"publish","type":"post","link":"https:\/\/blogs.sw.siemens.com\/polarion\/tech-tips-tricks-tips-to-solve-unruly-velocity-problems\/","title":{"rendered":"Tech Tips & Tricks: tips to solve unruly Velocity problems"},"content":{"rendered":"

Welcome to another installment in our series of tips and tricks from the Polarion Software Technical Support team, in which we share solutions we provided to customers for real-world use cases that. The same tips might help you too, or others on your team. Let’s look today at a couple of things with Velocity than can be frustrating until you know the trick. 
\n

Use Case<\/H2>
\nGet rid of the text line when variable is not defined in Velocity.<\/CODE><\/CODE>
\n

Solution<\/H2>
\nUse $!variable<\/CODE><\/CODE><\/p>\n

The difference is what it does when ‘variable’ is not defined. In that case ‘$’ renders the whole line as if it were plain text (which is not what you want in most cases), whereas ‘$’ outputs nothing. So using ‘$’ is usually a safer option.
\n

#set($y = $null)
\nOutput of $!y is:
\nOutput of $y is: $y<\/PRE>
\n
Use Case<\/H2>
\nEscaped special character (“) doesn’t work with Velocity.
\n
Solution<\/H2>
\nWe worked around the problem with quotes by saving the double quote character in to a variable x. (Please note the syntax ‘ ” ‘ – without spaces).
\n
#set($test = “WI-17”)
\n#set($x = ‘”‘)
\n#set($query = “id:${x}${test}${x}”)<\/PRE>
\nOutput is: id:”WI-17″<\/STRONG><\/p>\n
<\/p>\n
Jiri Jandl is a Senior Support Engineer with Polarion Software’s European tech support team. He is based in Prague, Czech Republic.<\/EM><\/p>\n

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