com.opensymphony.webwork.interceptor
Class ScopeInterceptor

java.lang.Object
  com.opensymphony.webwork.interceptor.ScopeInterceptor

All Implemented Interfaces:

com.opensymphony.xwork.interceptor.Interceptor, com.opensymphony.xwork.interceptor.PreResultListener, Serializable

public class ScopeInterceptor
extends Object
implements com.opensymphony.xwork.interceptor.Interceptor, com.opensymphony.xwork.interceptor.PreResultListener

This is designed to solve a few simple issues related to wizard-like functionality in WebWork. One of those issues is that some applications have a application-wide parameters commonly used, such pageLen (used for records per page). Rather than requiring that each action check if such parameters are supplied, this interceptor can look for specified parameters and pull them out of the session.

This works by setting listed properties at action start with values from session/application attributes keyed after the action's class, the action's name, or any supplied key. After action is executed all the listed properties are taken back and put in session or application context.

To make sure that each execution of the action is consistent it makes use of session-level locking. This way it guarantees that each action execution is atomic at the session level. It doesn't guarantee application level consistency however there has yet to be enough reasons to do so. Application level consistency would also be a big performance overkill.

Note that this interceptor takes a snapshot of action properties just before result is presented (using a PreResultListener), rather than after action is invoked. There is a reason for that: At this moment we know that action's state is "complete" as it's values may depend on the rest of the stack and specifically - on the values of nested interceptors.

Interceptor parameters:

• session - a list of action properties to be bound to session scope
• application - a list of action properties to be bound to application scope
• key - a session/application attribute key prefix, can contain following values:
• CLASS - that creates a unique key prefix based on action namespace and action class, it's a default value
• ACTION - creates a unique key prefix based on action namespace and action name
• any other value is taken literally as key prefix
• type - with one of the following
• start - means it's a start action of the wizard-like action sequence and all session scoped properties are reset to their defaults
• end - means that session scoped properties are removed from session after action is run
• any other value or no value means that it's in-the-middle action that is set with session properties before it's executed, and it's properties are put back to session after execution
• sessionReset - boolean value causing all session values to be reset to action's default values or application scope values, note that it is similliar to type="start" and in fact it does the same, but in our team it is sometimes semantically preferred. We use session scope in two patterns - sometimes there are wizzard-like action sequences that have start and end, and sometimes we just want simply reset current session values.

Extending the interceptor:

There are no know extension points for this interceptor.

Example code:

 
 <!-- As the filter and orderBy parameters are common for all my browse-type actions,
      you can move control to the scope interceptor. In the session parameter you can list
      action properties that are going to be automatically managed over session. You can
      do the same for application-scoped variables-->
 <action name="someAction" class="com.examples.SomeAction">
     <interceptor-ref name="basicStack"/>
     <interceptor-ref name="hibernate"/>
     <interceptor-ref name="scope">
         <param name="session">filter,orderBy</param>
         <param name="autoCreateSession">true</param>
     </interceptor-ref>
     <result name="success">good_result.ftl</result>
 </action>
 
 

Author:

Mike Mosiewicz, Rainer Hermanns

See Also:

Serialized Form

Constructor Summary

ScopeInterceptor()

Method Summary

protected void	after(com.opensymphony.xwork.ActionInvocation invocation, String result)
protected void	before(com.opensymphony.xwork.ActionInvocation invocation)
void	beforeResult(com.opensymphony.xwork.ActionInvocation invocation, String resultCode)
void	destroy()
String	getSessionReset()
String	getType()
void	init()
String	intercept(com.opensymphony.xwork.ActionInvocation invocation)
boolean	isReset()
void	setApplication(String s)
void	setAutoCreateSession(String value)
void	setKey(String key)
void	setReset(boolean reset)
void	setSession(String s)
void	setSessionReset(String sessionReset)
void	setType(String type)

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

ScopeInterceptor

public ScopeInterceptor()

Method Detail

setApplication

public void setApplication(String s)

setSession

public void setSession(String s)

setAutoCreateSession

public void setAutoCreateSession(String value)

after

protected void after(com.opensymphony.xwork.ActionInvocation invocation,
                     String result)
              throws Exception

Throws:

Exception

before

protected void before(com.opensymphony.xwork.ActionInvocation invocation)
               throws Exception

Throws:

Exception

setKey

public void setKey(String key)

beforeResult

public void beforeResult(com.opensymphony.xwork.ActionInvocation invocation,
                         String resultCode)

Specified by:

beforeResult in interface com.opensymphony.xwork.interceptor.PreResultListener

getType

public String getType()

setType

public void setType(String type)

getSessionReset

public String getSessionReset()

setSessionReset

public void setSessionReset(String sessionReset)

destroy

public void destroy()

Specified by:

destroy in interface com.opensymphony.xwork.interceptor.Interceptor

init

public void init()

Specified by:

init in interface com.opensymphony.xwork.interceptor.Interceptor

intercept

public String intercept(com.opensymphony.xwork.ActionInvocation invocation)
                 throws Exception

Specified by:

intercept in interface com.opensymphony.xwork.interceptor.Interceptor

Throws:

Exception

isReset

public boolean isReset()

setReset

public void setReset(boolean reset)