public interface VelocitySupport
custom queries, 
   transaction chaining,  
  dynamic security checking and 
  templated mail messages.  These are:
  queuing, this value will be
  identical to $currentDateHttpServletRequestDSRequest (though of course this is a
  server-side DSRequest object, so please also see the server-side Javadocs)DSRequest that caused the cache-sync request to be createdHttpSessionHttpServletRequest; it is an alternate form of 
  $servletRequest.getParameterHttpServletRequest; it is an alternate form of 
  $servletRequest.getAttributeHttpSession; it is an alternate form of 
  $session.getAttributeDataSources.  
  You access a dataSource by suffixing its name to the $dataSources designation.
  For example, $dataSources.supplyItem refers to the DataSource object called 
  "supplyItem".  You can use this approach to execute any valid DataSource method. One especially
  useful method in this context is hasRecord(fieldName, value) - see the 
  server-side Javadocs for more details.
  DataTools object, giving you access to all of that
      class's useful helper functionsMap interface, so you can use the Velocity "property" shorthand 
  notation to access them.  The following usage examples show five equivalent ways to return 
  the value of the session attribute named "foo":
  
     $session.foo
     $session.get("foo")
     $session.getAttribute("foo")
     $sessionAttributes.foo
     $sessionAttributes.get("foo")
  
  In the case of $servletRequest, the shorthand approach accesses the attributes 
  - you need to use either $httpParameters or $servletRequest.getParameter
  to access parameters. These examples all return the value of the HTTP parameter named "bar":
  
     $httpParameters.bar
     $httpParameters.get("bar")
     $servletRequest.getParameter("bar")
  
 When you use these Velocity variables in a customSQL 
 clause or SQL snippet such as a whereClause, all
 of 
  these template variables return values that have been correctly quoted and escaped according
   to the syntax of the underlying database.  We do this because "raw" values are vulnerable to 
  SQL injection attacks.
  If you need access to the raw value of a variable in a SQL template, you can use the 
  $rawValue qualifier in front of any of the template variables, like this:
    $rawValue.session.foo
  
  This also works for the $criteria and $values context variables (see 
  CustomQuerying for details of these variables).  So:
    $rawValue.criteria.customerName
  
$rawValue is only available in SQL templates.  It is not needed in
  other contexts, such as Transaction Chaining, because the value is not escaped and 
  quoted in these contexts.
  
  Warning:  Whenever you access a template variable for use in a SQL statement, bear 
  in mind that it is dangerous to use $rawValue.  There are some cases 
  where using the raw value is necessary, but even so, all such cases are likely to be vulnerable 
  to injection attacks.  Generally, the presence of $rawValue in a SQL template 
  should be viewed as a red flag.
  
  Finally, some example usages of these values.  
 These values clauses set "price" to a value extracted
 from the 
  session, and "lastUpdated" to the date/time that this transaction started:
    <values fieldName="price" value="$session.somePrice" />
    <values fieldName="lastUpdated" value="$transactionDate" />
  
  This whereClause selects some users based on various values passed in the criteria and 
  as HTTP parameters:
   <whereClause>department = $httpParameters.userDept AND dob >=
 $criteria.dateOfBirth</whereClause>
  
This whereClause selects some users based on various values obtained from the servletRequest's attributes, using a number of equivalent techniques for accessing the attributes:
    <whereClause>
          department = $servletRequest.dept 
      AND startDate >= $requestAttributes.dateOfBirth 
      AND salary < $servletRequest.getAttribute("userSalary")
    </whereClause>