How to Concatenate two variable in Velocity Code

[Suresh Venkat]

I am creating a User Macro in Confluence using Velocity Code. Need to concatenate two variables

using below code

##set($listofContent = $labelManager.getCurrentContentForLabelAndSpace() )

## set($labelManager = $action.getLabelManager() )

##set($label = $labelManager.getLabel() )

##set($newLabel = "")

##set($oldLabel = "")

#foreach ($labelling in $page.getLabellings () )

#set ($label = $labelling.getLabel() )

#set ($oldLabel = $label)

##here I would like to concatenate Old Label + New Label, so that I can get all labels

##below command is not working

#set ($newLabel = $oldLabel$newLabel)

## where am I going wrong?

#end

[Bill Bailey]

Well straight concatenation would just be

#set ($newLabel = $oldLabel + $newLabel)

But if $oldLabel = "foo" and $newLabel = "bar", then the result will be foobar.  So if you want some sort of delimiter, then you need to do something like this:

#set ($newLabel = $oldLabel + ', ' + $newLabel)

to result in foo, bar

[Suresh Venkat]

@Bill Bailey : While old label prints the latest label on a page, newlabel would simply print $newLabel as the value of label, with both the options provided. 

I tried setting the initial values as 

##set($newLabel = ' ')

##set($oldLabel = ' ' )

That did not help either. Referred  and implemented from this  link http://people.apache.org/~henning/velocity/html/ch09s05.html. Still no avail.

[Bill Bailey]

You do realize that ## is the syntax for a comment, so those lines will not operate?

I would also suggest looking at the latest guide:

http://velocity.apache.org/engine/2.2/user-guide.html#string-concatenation

It suggest using

#set ($newLabel = $oldLabel$newLabel)

But I have typically used the + operation as I often need to mix in HTML code. Either should work.

It has been awhile since I worked with labels, but you may have to convert the object to a string one of two ways:

$label.toString()

or

$label.name

[Suresh Venkat]

Ok. will have to reach out to dev@velocity.apache.org, as trying all options has not worked. FYI, without converting oldLabel is printing the latest label as it is. Hence..

But, Thanks for offering the advice

[Bill Bailey]

Also, I don't think I have seen a method .getLabellings () (note that there should not be space between the method and () ).

The method I have always used was .getLabels()

[Suresh Venkat]

@Bill Bailey Space was a typo. I referred example given at https://community.atlassian.com/t5/Confluence-questions/How-do-I-list-all-pages-with-titles-and-last-modified-by-and/qaq-p/41974. getLabel is working.

[Bill Bailey]

Yeah, that article is from 2015 so I think version 5. It may be that .getlabellings() was deprecated, or a method added by another plugin?