com.opensymphony.xwork.interceptor
Class ExceptionMappingInterceptor

java.lang.Object
  com.opensymphony.xwork.interceptor.ExceptionMappingInterceptor

All Implemented Interfaces:

Interceptor

public class ExceptionMappingInterceptor
extends Object
implements Interceptor

This interceptor forms the core functionality of the exception handling feature. Exception handling allows you to map an exception to a result code, just as if the action returned a result code instead of throwing an unexpected exception. When an exception is encountered, it is wrapped with an ExceptionHolder and pushed on the stack, providing easy access to the exception from within your result. Note: While you can configure exception mapping in your configuration file at any point, the configuration will not have any effect if this interceptor is not in the interceptor stack for your actions. It is recommended that you make this interceptor the first interceptor on the stack, ensuring that it has full access to catch any exception, even those caused by other interceptors.

Interceptor parameters:

• None

Extending the interceptor:

If you want to add custom handling for publishing the Exception, you may override publishException(com.opensymphony.xwork.ActionInvocation, ExceptionHolder). The default implementation pushes the given ExceptionHolder on value stack. A custom implementation could add additional logging etc.

Example code:

 
 <xwork>
     <include file="webwork-default.xml"/>

     <package name="default" extends="webwork-default">
         <global-results>
             <result name="success" type="freemarker">error.ftl</result>
         </global-results>

         <global-exception-mappings>
             <exception-mapping exception="java.lang.Exception" result="error"/>
         </global-exception-mappings>

         <action name="test">
             <interceptor-ref name="exception"/>
             <interceptor-ref name="basicStack"/>
             <exception-mapping exception="com.acme.CustomException" result="custom_error"/>
             <result name="custom_error">custom_error.ftl</result>
             <result name="success" type="freemarker">test.ftl</result>
         </action>
     </package>
 </xwork>
 
 

Author:

Matthew E. Porter (matthew dot porter at metissian dot com) Date: Aug 14, 2005 Time: 12:40:02 PM

Field Summary

protected org.apache.commons.logging.Log

log

Constructor Summary

ExceptionMappingInterceptor()

Method Summary

void	destroy() Called to let an interceptor clean up any resources it has allocated.
int	getDepth(String exceptionMapping, Throwable t) Return the depth to the superclass matching.
void	init() Called after an interceptor is created, but before any requests are processed using intercept , giving the Interceptor a chance to initialize any needed resources.
String	intercept(ActionInvocation invocation) Allows the Interceptor to do some processing on the request before and/or after the rest of the processing of the request by the ActionInvocation or to short-circuit the processing and just return a String return code.
protected void	publishException(ActionInvocation invocation, ExceptionHolder exceptionHolder) Default implementation to handle ExceptionHolder publishing.

Methods inherited from class java.lang.Object

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

Field Detail

log

protected org.apache.commons.logging.Log log

Constructor Detail

ExceptionMappingInterceptor

public ExceptionMappingInterceptor()

Method Detail

destroy

public void destroy()

Description copied from interface: Interceptor

Called to let an interceptor clean up any resources it has allocated.

Specified by:

destroy in interface Interceptor

init

public void init()

Description copied from interface: Interceptor

Called after an interceptor is created, but before any requests are processed using intercept , giving the Interceptor a chance to initialize any needed resources.

Specified by:

init in interface Interceptor

intercept

public String intercept(ActionInvocation invocation)
                 throws Exception

Description copied from interface: Interceptor

Allows the Interceptor to do some processing on the request before and/or after the rest of the processing of the request by the ActionInvocation or to short-circuit the processing and just return a String return code.

Specified by:

intercept in interface Interceptor

Returns:

the return code, either returned from ActionInvocation.invoke(), or from the interceptor itself.

Throws:

Exception - any system-level error, as defined in Action.execute().

getDepth

public int getDepth(String exceptionMapping,
                    Throwable t)

Return the depth to the superclass matching. 0 means ex matches exactly. Returns -1 if there's no match. Otherwise, returns depth. Lowest depth wins.

publishException

protected void publishException(ActionInvocation invocation,
                                ExceptionHolder exceptionHolder)

Default implementation to handle ExceptionHolder publishing. Pushes given ExceptionHolder on the stack. Subclasses may override this to customize publishing.

Parameters:

invocation - The invocation to publish Exception for.

exceptionHolder - The exceptionHolder wrapping the Exception to publish.