com.opensymphony.xwork2.interceptor
Class PrepareInterceptor

java.lang.Object
  extended by com.opensymphony.xwork2.interceptor.AbstractInterceptor
      extended by com.opensymphony.xwork2.interceptor.PrepareInterceptor
All Implemented Interfaces:
Interceptor, java.io.Serializable

public class PrepareInterceptor
extends AbstractInterceptor

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.

Update: Added logic to execute a prepare{MethodName} and conditionally the a general prepare() Method, depending on the 'alwaysInvokePrepare' parameter/property which is by default true. This allows us to run some logic based on the method name we specify in the ActionProxy. For example, you can specify a prepareInput() method that will be run before the invocation of the input method.

Interceptor parameters:

Extending the interceptor:

There are no known extension points to this interceptor.

Example code:

 
 <!-- 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>
 
 
Date: Nov 5, 2003 2:33:11 AM

Author:
Jason Carreira, Philip Luppens, tm_jee
See Also:
Preparable, Serialized Form

Constructor Summary
PrepareInterceptor()
           
 
Method Summary
 java.lang.String intercept(ActionInvocation invocation)
          Override to handle interception
 void setAlwaysInvokePrepare(java.lang.String alwaysInvokePrepare)
           
 
Methods inherited from class com.opensymphony.xwork2.interceptor.AbstractInterceptor
destroy, init
 
Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
 

Constructor Detail

PrepareInterceptor

public PrepareInterceptor()
Method Detail

setAlwaysInvokePrepare

public void setAlwaysInvokePrepare(java.lang.String alwaysInvokePrepare)

intercept

public java.lang.String intercept(ActionInvocation invocation)
                           throws java.lang.Exception
Description copied from class: AbstractInterceptor
Override to handle interception

Specified by:
intercept in interface Interceptor
Specified by:
intercept in class AbstractInterceptor
Returns:
the return code, either returned from ActionInvocation.invoke(), or from the interceptor itself.
Throws:
java.lang.Exception - any system-level error, as defined in Action.execute().


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