org.apache.struts2.interceptor
Class ScopeInterceptor

java.lang.Object
  extended by com.opensymphony.xwork2.interceptor.AbstractInterceptor
      extended by org.apache.struts2.interceptor.ScopeInterceptor
All Implemented Interfaces:
Interceptor, PreResultListener, java.io.Serializable

public class ScopeInterceptor
extends AbstractInterceptor
implements PreResultListener

This is designed to solve a few simple issues related to wizard-like functionality in Struts. 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:

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>
 
 

See Also:
Serialized Form

Constructor Summary
ScopeInterceptor()
          The constructor
 
Method Summary
protected  void after(ActionInvocation invocation, java.lang.String result)
           
protected  void before(ActionInvocation invocation)
           
 void beforeResult(ActionInvocation invocation, java.lang.String resultCode)
           
 java.lang.String getSessionReset()
           
 java.lang.String getType()
           
 java.lang.String intercept(ActionInvocation invocation)
           
 boolean isReset()
           
 void setApplication(java.lang.String s)
          Sets a list of application scoped properties
 void setAutoCreateSession(java.lang.String value)
          Sets if the session should be automatically created
 void setKey(java.lang.String key)
           
 void setReset(boolean reset)
           
 void setSession(java.lang.String s)
          Sets a list of session scoped properties
 void setSessionReset(java.lang.String sessionReset)
           
 void setType(java.lang.String type)
          Sets the type of scope operation
 
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

ScopeInterceptor

public ScopeInterceptor()
The constructor

Method Detail

setApplication

public void setApplication(java.lang.String s)
Sets a list of application scoped properties

Parameters:
s - A comma-delimited list

setSession

public void setSession(java.lang.String s)
Sets a list of session scoped properties

Parameters:
s - A comma-delimited list

setAutoCreateSession

public void setAutoCreateSession(java.lang.String value)
Sets if the session should be automatically created

Parameters:
value - True if it should be created

after

protected void after(ActionInvocation invocation,
                     java.lang.String result)
              throws java.lang.Exception
Throws:
java.lang.Exception

before

protected void before(ActionInvocation invocation)
               throws java.lang.Exception
Throws:
java.lang.Exception

setKey

public void setKey(java.lang.String key)

beforeResult

public void beforeResult(ActionInvocation invocation,
                         java.lang.String resultCode)
Specified by:
beforeResult in interface PreResultListener

getType

public java.lang.String getType()
Returns:
The type of scope operation, "start" or "end"

setType

public void setType(java.lang.String type)
Sets the type of scope operation

Parameters:
type - Either "start" or "end"

getSessionReset

public java.lang.String getSessionReset()
Returns:
Gets the session reset parameter name

setSessionReset

public void setSessionReset(java.lang.String sessionReset)
Parameters:
sessionReset - The session reset parameter name

intercept

public java.lang.String intercept(ActionInvocation invocation)
                           throws java.lang.Exception
Specified by:
intercept in interface Interceptor
Specified by:
intercept in class AbstractInterceptor
Throws:
java.lang.Exception

isReset

public boolean isReset()
Returns:
True if the scope is reset

setReset

public void setReset(boolean reset)
Parameters:
reset - True if the scope should be reset


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