[jira] Commented: (WW-2071) UIBean.end does not fail when an exception happens

["DavidZaz (JIRA)" <ji...@apache.org>]

    [ https://issues.apache.org/struts/browse/WW-2071?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=44926#action_44926 ] 

DavidZaz commented on WW-2071:
------------------------------

Lines 480-492 in UIBean.java illustrate the problem:

  480       public boolean end(Writer writer, String body) {
  481           evaluateParams();
  482           try {
  483               super.end(writer, body, false);
  484               mergeTemplate(writer, buildTemplateName(template, getDefaultTemplate()));
  485           } catch (Exception e) {
  486               LOG.error("error when rendering", e);
  487           }
  488           finally {
  489               popComponentStack();
  490           }
  491   
  492           return false;

In the catch block, the exception is logged, but no special value is returned to indicate failure. The remainder of the JSP page will still be parsed and the same exception gets thrown multiple times. This occurs since UIBean.end always returns 'false' and UIBean.MergeTemplate (see line 530) does not even check the return result from UIBean.end.

To reproduce this problem, use the following test case:

1. Create a Struts action which populates a very large List (maybe 5-10 thousand elements).
2. Create a JSP page which iterates through the List and displays the elements on the page.
3. While the JSP page is loading (but before it is complete), navigate away from the loading page.

This causes the output stream to be closed. Yet UIBean.end keeps calling super.end(writer, body, false) on the closed writer object. The exception is then caught and displayed in my server log. Since no failure value is returned, Struts continues iterating over the remainder of the List and logs an exception for each list element. For large lists, this produces a ridiculous amount of log data by repeatedly printing out the same exception.

Would it be possible to make this error handling more robust so that Struts would realize that the UIBean.end method is failing and stop retrying the same operation? I tried to work around this bug by writing my own ExceptionMappingInterceptor. My interceptor was able to catch the exception, but not until after UIBean.end had produced thousands of log entries. The best solution would be to fix UIBean.end and UIBean.MergeTemplate to take appropriate action when an exception is thrown.

Here is a sample stacktrace:

[06/Nov/2008:09:19:01] info ( 4768): CORE3282: stdout: ERROR - UIBean.end(486) | error when rendering
[06/Nov/2008:09:19:01] info ( 4768): CORE3282: stdout: java.io.IOException: WEB8004: Error flushing the output stream
[06/Nov/2008:09:19:01] info ( 4768): CORE3282: stdout: 	at com.iplanet.ias.web.connector.nsapi.NSAPIConnector.flush(NSAPIConnector.java:743)
[06/Nov/2008:09:19:01] info ( 4768): CORE3282: stdout: 	at com.iplanet.ias.web.connector.nsapi.NSAPIResponseStream.flush(NSAPIResponseStream.java:97)
[06/Nov/2008:09:19:01] info ( 4768): CORE3282: stdout: 	at com.iplanet.ias.web.connector.nsapi.NSAPIResponse.flushBuffer(NSAPIResponse.java:131)
[06/Nov/2008:09:19:01] info ( 4768): CORE3282: stdout: 	at org.apache.catalina.connector.ResponseFacade.flushBuffer(ResponseFacade.java:219)
[06/Nov/2008:09:19:01] info ( 4768): CORE3282: stdout: 	at javax.servlet.ServletResponseWrapper.flushBuffer(ServletResponseWrapper.java:189)
[06/Nov/2008:09:19:01] info ( 4768): CORE3282: stdout: 	at org.apache.jasper.runtime.JspWriterImpl.flush(JspWriterImpl.java:227)
[06/Nov/2008:09:19:01] info ( 4768): CORE3282: stdout: 	at freemarker.core.Environment.process(Environment.java:178)
[06/Nov/2008:09:19:01] info ( 4768): CORE3282: stdout: 	at freemarker.template.Template.process(Template.java:232)
[06/Nov/2008:09:19:01] info ( 4768): CORE3282: stdout: 	at org.apache.struts2.components.template.FreemarkerTemplateEngine.renderTemplate(FreemarkerTemplateEngine.java:168)
[06/Nov/2008:09:19:01] info ( 4768): CORE3282: stdout: 	at org.apache.struts2.components.UIBean.mergeTemplate(UIBean.java:530)
[06/Nov/2008:09:19:01] info ( 4768): CORE3282: stdout: 	at org.apache.struts2.components.UIBean.end(UIBean.java:484)
[06/Nov/2008:09:19:01] info ( 4768): CORE3282: stdout: 	at org.apache.struts2.views.jsp.ComponentTagSupport.doEndTag(ComponentTagSupport.java:43)

> UIBean.end does not fail when an exception happens
> --------------------------------------------------
>
>                 Key: WW-2071
>                 URL: https://issues.apache.org/struts/browse/WW-2071
>             Project: Struts 2
>          Issue Type: Bug
>          Components: Plugin - Tags
>    Affects Versions: 2.1.0
>            Reporter: Antonio Petrelli
>             Fix For: 2.1.3
>
>
> UIBean.end does not fail if something wrong happens in calling "super.end" or when merging template.

-- 
This message is automatically generated by JIRA.
-
You can reply to this email to add a comment to the issue online.