[ https://issues.apache.org/jira/browse/VELTOOLS-139?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13014055#comment-13014055 ]
Nathan Bubna commented on VELTOOLS-139: --------------------------------------- Not just any undefined variable. Use $NULL or $null. If someone with access to the context is putting in a non-null value with "NULL" or "null" as the key, you have problems. In fact, my primary objection to the NullTool is the implied/suggested key of $null. Terrible idea! Maybe an isNull(Object) method could easily be added to the ContextTool (which does have a $context.contains('var') method that is very close). But personally, i think #if( $var == $null ) is very straightforward and cleaner than $context.isNull($var). > Bundle a NullTool in velocity Tools > ----------------------------------- > > Key: VELTOOLS-139 > URL: https://issues.apache.org/jira/browse/VELTOOLS-139 > Project: Velocity Tools > Issue Type: Wish > Components: GenericTools > Affects Versions: 2.0 > Reporter: Vincent Massol > > Right now, in order to check for null we have to use: > {code}#if ((! $var) && ("$!var" == "")){code} > which is painful when you have lots of checks to do in several places. > It would be nice either to have better null check support in velocity core or > to bundle to NullTool in Velocity Tools: > http://wiki.apache.org/velocity/NullTool > I checked the user guide and googled around and couldn't find any simple way > to check for null except using an undefined variable which I find way too > magical and dangerous (what if someone defines that variable in the context). -- This message is automatically generated by JIRA. For more information on JIRA, see: http://www.atlassian.com/software/jira --------------------------------------------------------------------- To unsubscribe, e-mail: dev-unsubscr...@velocity.apache.org For additional commands, e-mail: dev-h...@velocity.apache.org