Gary Affonso on 09/12/07 23:58, wrote:
Yayo wrote:
Errors are stored in a request scope attribute and after a redirect
they're
lost because a new request is launched by the client browser. You must
explicitly (by code) store them in a session attribute to get them in the
second request.
Preserving the messages by hand will work, of course. But there's a
nifty interceptor (MessageStoreInteceptor) that will do that for you now...
http://struts.apache.org/2.0.11/docs/message-store-interceptor.html
I keep meaning to put a stripped-down version of MessageStoreInterceptor up on
the web - perhaps I should add it as a Jira issue?
Anyway, I wanted the interceptor to display success messages after a redirect.
The messages / errors only need to survive until the next request. So anything
in the request I put into the session (in the after method) and in the before
method, anything in the session, I remove and put into the request.
Very simple, fulfills the requirement and doesn't need any configuration telling
it when to save or when to discard.
package org.permacode.web;
import java.util.ArrayList;
import java.util.Collection;
import java.util.LinkedHashMap;
import java.util.Map;
import javax.servlet.http.HttpSession;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.apache.struts2.ServletActionContext;
import org.apache.struts2.dispatcher.ServletRedirectResult;
import com.opensymphony.xwork2.ActionInvocation;
import com.opensymphony.xwork2.ValidationAware;
import com.opensymphony.xwork2.interceptor.Interceptor;
public class MessageHandlingInterceptor implements Interceptor
{
private static final long serialVersionUID = 4491997514314242420L;
private static final Log logger =
LogFactory.getLog(MessageHandlingInterceptor.class);
public static String FIELD_ERRORS =
MessageHandlingInterceptor.class.getCanonicalName()
+ ".FieldErrors.key";
public static String ACTION_ERRORS =
MessageHandlingInterceptor.class.getCanonicalName()
+ ".ActionErrors.key";
public static String ACTION_MESSAGES =
MessageHandlingInterceptor.class.getCanonicalName()
+ ".ActionMessages.key";
public void destroy()
{
}
public void init()
{
}
public String intercept(ActionInvocation invocation) throws Exception
{
logger.debug("entering interceptor....");
before(invocation);
String result = invocation.invoke();
after(invocation, result);
logger.debug("done interceptor.");
return result;
}
/**
* Handle the retrieving of field errors / action messages / field errors,
* which is done before action invocation.
*
* @param invocation
* @throws Exception
*/
protected void before(ActionInvocation invocation) throws Exception
{
HttpSession session =
ServletActionContext.getRequest().getSession();
Object action = invocation.getAction();
if (action instanceof ValidationAware)
{
// retrieve error / message from session
ValidationAware validationAwareAction = (ValidationAware) action;
Collection errors =
(Collection) session.getAttribute(ACTION_ERRORS);
if (errors != null && errors.size() > 0)
{
logger.debug("retrieve error from session "
+ "to populate into action [" + action + "]");
Collection mergedErrors =
mergeCollection(validationAwareAction.getActionErrors(),
errors);
validationAwareAction.setActionErrors(mergedErrors);
}
Collection messages =
(Collection) session.getAttribute(ACTION_MESSAGES);
if (messages != null && messages.size() > 0)
{
logger.debug("retrieve message from session "
+ "to populate into action [" + action + "]");
Collection mergedMessages =
mergeCollection(validationAwareAction.getActionMessages(),
messages);
validationAwareAction.setActionMessages(mergedMessages);
}
Map fieldErrors = (Map) session.getAttribute(FIELD_ERRORS);
if (fieldErrors != null && fieldErrors.size() > 0)
{
logger.debug("retrieve field errors from session "
+ "to populate into action [" + action + "]");
Map mergedFieldErrors =
mergeMap(validationAwareAction.getFieldErrors(),
fieldErrors);
validationAwareAction.setFieldErrors(mergedFieldErrors);
}
}
session.removeAttribute(ACTION_ERRORS);
session.removeAttribute(ACTION_MESSAGES);
session.removeAttribute(FIELD_ERRORS);
}
/**
* Handle the storing of field errors / action messages / field errors,
* which is done after action invocation when result is a redirect.
*
* @param invocation
* @param result
* @throws Exception
*/
protected void after(ActionInvocation invocation, String result)
throws Exception
{
Object action = invocation.getAction();
if (action instanceof ValidationAware
&& invocation.getResult() instanceof ServletRedirectResult)
{
// store error / messages into session
HttpSession session =
ServletActionContext.getRequest().getSession();
logger.debug("store action [" + action
+ "] error/messages into session ");
ValidationAware validationAwareAction = (ValidationAware) action;
session.setAttribute(ACTION_ERRORS, validationAwareAction
.getActionErrors());
session.setAttribute(ACTION_MESSAGES, validationAwareAction
.getActionMessages());
session.setAttribute(FIELD_ERRORS, validationAwareAction
.getFieldErrors());
}
}
/**
* Merge <code>col1</code> and <code>col2</code> and return the
* composite <code>Collection</code>.
*
* @param col1
* @param col2
* @return Collection
*/
protected Collection mergeCollection(Collection col1, Collection col2)
{
Collection _col1 = (col1 == null ? new ArrayList()
: col1);
Collection _col2 = (col2 == null ? new ArrayList()
: col2);
_col1.addAll(_col2);
return _col1;
}
/**
* Merge <code>map1</code> and <code>map2</code> and return the
* composite <code>Map</code>
*
* @param map1
* @param map2
* @return Map
*/
protected Map mergeMap(Map map1, Map map2)
{
Map _map1 = (map1 == null ? new LinkedHashMap()
: map1);
Map _map2 = (map2 == null ? new LinkedHashMap()
: map2);
_map1.putAll(_map2);
return _map1;
}
}
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