Page Comparison

Some tutorials on the internet recommend setting a variable $Integer to the constant of 0 and then calling parseInt method on it like this:

#set ($Integer = 0)
#if ($parameters.get("ItemsPerPage"))
  #set ($ItemsPerPage = $Integer.parseInt($parameters.get("ItemsPerPage")))
#else
  #set ($ItemsPerPage = 6)
#end

The problem is that $Integer.parseInt won't handle bad input gracefully.  Instead the proper way to code this type of logic is:

#set ($ItemsPerPage = 6)
#if ($formatHelper.parseInteger($parameters.get("ItemsPerPage")))
  #set ($ItemsPerPage = $formatHelper.parseInteger($parameters.get("ItemsPerPage")))
  #if ($ItemPerPage < 1 || $ItemPerPage > 50)
    #set ($ItemsPerPage = 6)
  #end
#end

Notice that we default to 6, if the parameter is parsable then we'll assign it's parsed value to the ItemsPerPage variable.  $Integer.parseIntWe then sanity check the range of the value to make sure it's reasonable.