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.

In PrepareInterceptor

Applies only when action implements Preparable

1. if the action class have prepare{MethodName}(), it will be invoked
2. else if the action class have prepareDo(MethodName()}(), it will be invoked
3. no matter if 1] or 2] is performed, if alwaysinvokePrepare property of the interceptor is "true" (which is by default "true"), prepare() will be invoked.

Parameters

• None

Extending the Interceptor

There are no known extension points to this interceptor.

Examples

<!-- 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>