public interface VelocitySupport
custom
queries,
transaction chaining,
dynamic security checking
and
templated mail messages. These are:
queuing,
this value will be
identical to $currentDatequeuing,
this value will be
identical to $currentDateTimeConfig object (though of course this is a
server-side object, so please see the server-side Javadocs)HttpServletRequestDSRequest (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 functionsLogger instance in category "velocityTemplate"RPCManagerRPCManager (synonym to $rpc)
#if ($storedRecord.recordExists())
$value > $storedRecord.valInt
#else
true
#endcom.isomorphic.velocity.ResponseDataWrapper; see the server-side Javadoc
for details of that class. This context variable is particularly useful in a
TransactionChaining context, as you can optionally refer to
the first or
last DSResponse for a given DataSource or DataSource/operation type combination. This
support is implemented by com.isomorphic.velocity.ResponseDataHandler; see
its server-side Javadoc for details. Note, this variable is only present if you have
Power Edition or better$responseData, you can optionally refer to
the first or last response for a given DataSource or DataSource/operation type
combination. See the server-side Javadoc for
com.isomorphic.velocity.ResponsesHandler for details. Note, this variable
is only present if you have Power Edition or betterMap 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>
If you are using the Java server and would like to add your own Java objects to the
server-side Velocity context, you can do so on a per-request basis via
DSRequest.addToTemplateContext() or globally by using Velocity Tools. The
Velocity Tools mechanism is described here:
http://velocity.apache.org/tools/releases/2.0/index.html.
Just add the velocity tools jars to your deployment and place your tools.xml
configuration file in the CLASSPATH (typically WEB-INF/classes).
Additionally, if you would like to modify the Velocity Engine defaults, you can provide your
own velocity.properties at the top level of the CLASSPATH (again, typically in
WEB-INF/classes). These settings will overlay and override the defaults provided the
velocity.properties file that ships inside the Velocity jar.
VelocityExpression