Jakarta Commons Cookbook

9.8. Using Macros in a Templating Engine

Problem

You need to reuse portions of a template to standardize the display of common elements such as an address or a name.

Solution

Use Velocity Macro definitions to reuse logic to print out both names and addresses. Velocity macros are like subroutines that take a set of parameters and perform common tasks. In the following Velocity template, two macros, #name and #address, handle the printing of names and addresses:

#set( $volunteer = $appointment.volunteer ) #set( $location = $appointment.location ) #set( $org = $appointment.organization ) ## Define the "name" macro #macro( name $object )$!object.firstName $!object.lastName#end ## Define the "address" macro #macro( address $object ) $!object.address.street1 $!object.address.street2 $!object.address.city, $!object.address.state $!object.address.zipcode #end #name( $volunteer ), Thank you for volunteering to help serve food at the $location.name next week. This email is a reminder that you are scheduled to help out from $appointment.startTime to $appointment.endTime on $appointment.date. The address of the shelter is: #address( $location ) If you need directions to the shelter click the following URL: ${org.baseUrl}directions?location=${location.id} Also, if you are unable to help out on $appointment.date, please let us know by sending an email to ${org.email} or by filling out the form at this URL: ${org.baseUrl}planschange?appointment=${appointment.id} Thanks again, #name( $org.president ...