This interceptor calls prepare()
on actions which implement Preparable
. This interceptor is very useful for any situation where you need to ensure some logic runs before the actual execute method runs.
A typical use of this is to run some logic to load an object from the database so that when parameters are set they can be set on this object. For example, suppose you have a User object with two properties: id
and name
. Provided that the params interceptor is called twice (once before and once after this interceptor), you can load the User object using the id
property and then when the second params interceptor is called the parameter user.name
will be set, as desired, on the actual object loaded from the database. See the example for more info.
Note: Since XWork 2.0.2, this interceptor extends
MethodFilterInterceptor
, therefore being able to deal withexcludeMethods
/includeMethods
parameters. See Workflow Interceptor for documentation and examples on how to use this feature.
Update: Added logic to execute a
prepare<MethodName>
and conditionally the a generalprepare()
Method, depending on thealwaysInvokePrepare
parameter/property which is by defaulttrue
. This allows us to run some logic based on the method name we specify in thecom.opensymphony.xwork2.ActionProxy
. For example, you can specify aprepareInput()
method that will be run before the invocation of the input method.
In PrepareInterceptor
applies only when action implements Preparable
prepare<MethodName>()
, it will be invokedprepareDo<MethodName>()
, it will be invokedalwaysInvokePrepare
property of the interceptor is true
(which is by default true
), prepare()
will be invoked.alwaysInvokePrepare
- Default to true. If true, prepare will always be invoked, otherwise it will not.There are no known extension points to this interceptor.
<!-- Calls the params interceptor twice, allowing you to pre-load data for the second time parameters are set --> <action name="someAction" class="com.examples.SomeAction"> <interceptor-ref name="params"/> <interceptor-ref name="prepare"/> <interceptor-ref name="basicStack"/> <result name="success">good_result.ftl</result> </action>