Author: buildbot
Date: Sat Apr 21 20:20:05 2018
New Revision: 1028750
Log:
Production update by buildbot for tapestry
Modified:
websites/production/tapestry/content/cache/main.pageCache
websites/production/tapestry/content/runtime-exceptions.html
Modified: websites/production/tapestry/content/cache/main.pageCache
==============================================================================
Binary files - no diff available.
Modified: websites/production/tapestry/content/runtime-exceptions.html
==============================================================================
--- websites/production/tapestry/content/runtime-exceptions.html (original)
+++ websites/production/tapestry/content/runtime-exceptions.html Sat Apr 21
20:20:05 2018
@@ -75,13 +75,75 @@
</div>
<div id="content">
- <div id="ConfluenceContent"><p>Feedback is vitally important
when developing an application, and that is one of the areas where Tapestry has
always excelled.</p><p>Especially during development, requests can fail. There
can be errors in templates, broken code in your application, or something
unexpected.</p><p>Tapestry has a built-in exception report page that captures
an amazing wealth of information:</p><p><span
class="confluence-embedded-file-wrapper confluence-embedded-manual-size"><img
class="confluence-embedded-image confluence-content-image-border" width="500"
src="runtime-exceptions.data/Exception_Stack_Trace.png"></span></p><p><span
class="confluence-embedded-file-wrapper confluence-embedded-manual-size"><img
class="confluence-embedded-image confluence-content-image-border" width="500"
src="runtime-exceptions.data/Exception_Request.png"></span></p><p><span
class="confluence-embedded-file-wrapper confluence-embedded-manual-size"><img
class="confluence-embedde
d-image confluence-content-image-border" height="443" width="500"
src="runtime-exceptions.data/Application_Exception.png"></span></p><p>This
exception report features:</p><ul><li>The full stack of exceptions, top to
bottom.</li><li>All non-null properties of each exception.</li><li>The stack
trace <em>at the deepest
level</em>.</li><li>Key <strong>request</strong> properties, header,
attributes, and
parameters.</li><li>Key <strong>session</strong><em> </em>propertes</li><li>A
break down of the <em>thread</em> in your application</li><li>A listing
of all JVM System properties<br clear="none"><br clear="none"></li></ul><p>In
addition, Tapestry will write a text file for the exception with a similar
level of detail. The default location for the exception files is a relative
directory <em>build/exceptions</em>. You can configure the location by setting
<a class="external-link"
href="http://tapestry.apache.org/current/apidocs/org/apache/tapestry5/SymbolConstants
.html#EXCEPTION_REPORTS_DIR">SymbolConstants.EXCEPTION_REPORTS_DIR</a>.</p><p>This
exception report is also built-in to Tapestry's Ajax support. When an Ajax
request fails, Tapestry's client-side code will create an <iframe> to
present this same information:</p><p><span
class="confluence-embedded-file-wrapper confluence-embedded-manual-size"><img
class="confluence-embedded-image confluence-content-image-border" height="359"
width="500" src="runtime-exceptions.data/Exception_Ajax.png"></span></p><p>In
production, you may want to <a
href="overriding-exception-reporting.html">override the exception report
page</a> (but will likely keep the text file output). However, Tapestry's (from
version 5.4) default exception reporter also allows you to handle specific
exception types in a pre-determined manner, similar to how servlet spec's
standard error-page/exception-type configuration option allows you to map
exception types to URLs. At times, it's simpler to just catch exceptions at t
he outermost layer of your application instead of carrying a typed exception
through multiple layers of abstractions just so you could show a sensible error
message to the user, especially if you can't do anything more clever about it
anyway. Exception type mapping in Tapestry is much more powerful than what the
servlet spec dictates. If your email service or an external payment service
goes down, you can't do much more than display an error message to the user, so
why would you need to implement separate pages for each exception? Often, it'd
be nicer if you could just reuse the page template for any fatal exception and
simply display a different error message. In addition to contributing handlers
for specific types of exceptions, you may also provide context for rendering
the same error page template with a different output.</p><p>You can contribute
an error page, mapping it to an exception type:</p><div class="code panel pdl"
style="border-width: 1px;"><div class="codeContent pane
lContent pdl">
+ <div id="ConfluenceContent"><div class="aui-label"
style="float:right" title="Related Articles">
+
+
+
+
+
+
+
+
+<h3>Related Articles</h3>
+
+<ul class="content-by-label"><li>
+ <div>
+ <span class="icon aui-icon aui-icon-small
aui-iconfont-page-default" title="Page">Page:</span> </div>
+
+ <div class="details">
+ <a href="error-page-recipe.html">Error Page Recipe</a>
+
+
+ </div>
+ </li><li>
+ <div>
+ <span class="icon aui-icon aui-icon-small
aui-iconfont-page-default" title="Page">Page:</span> </div>
+
+ <div class="details">
+ <a href="specific-errors-faq.html">Specific Errors
FAQ</a>
+
+
+ </div>
+ </li><li>
+ <div>
+ <span class="icon aui-icon aui-icon-small
aui-iconfont-page-default" title="Page">Page:</span> </div>
+
+ <div class="details">
+ <a
href="overriding-exception-reporting.html">Overriding Exception Reporting</a>
+
+
+ </div>
+ </li></ul>
+</div>
+
+
+<p>Feedback is vitally important when developing an application, and that is
one of the areas where Tapestry has always excelled.</p><p>Especially during
development, requests can fail. There can be errors in templates, broken code
in your application, or something unexpected.</p><p><style
type="text/css">/*<![CDATA[*/
+div.rbtoc1524341981608 {padding: 0px;}
+div.rbtoc1524341981608 ul {list-style: disc;margin-left: 0px;}
+div.rbtoc1524341981608 li {margin-left: 0px;padding-left: 0px;}
+
+/*]]>*/</style></p><div class="toc-macro rbtoc1524341981608">
+<ul class="toc-indentation"><li><a
href="#RuntimeExceptions-Build-inExceptionReportPage">Build-in Exception Report
Page</a></li><li><a
href="#RuntimeExceptions-DetailedExceptionReportFiles">Detailed Exception
Report Files</a></li><li><a
href="#RuntimeExceptions-AjaxDetailedExceptionReports">Ajax Detailed Exception
Reports</a></li><li><a
href="#RuntimeExceptions-OverridingtheHandlingofSpecificExceptions">Overriding
the Handling of Specific Exceptions</a></li></ul>
+</div><h2 id="RuntimeExceptions-Build-inExceptionReportPage">Build-in
Exception Report Page</h2><p>Tapestry has a built-in exception report page that
captures an amazing wealth of information:</p><p><span
class="confluence-embedded-file-wrapper confluence-embedded-manual-size"><img
class="confluence-embedded-image confluence-content-image-border" width="500"
src="runtime-exceptions.data/Exception_Stack_Trace.png"></span></p><p><span
class="confluence-embedded-file-wrapper confluence-embedded-manual-size"><img
class="confluence-embedded-image confluence-content-image-border" width="500"
src="runtime-exceptions.data/Exception_Request.png"></span></p><p><span
class="confluence-embedded-file-wrapper confluence-embedded-manual-size"><img
class="confluence-embedded-image confluence-content-image-border" height="443"
width="500"
src="runtime-exceptions.data/Application_Exception.png"></span></p><p>This
exception report features:</p><ul><li>The full stack of exceptions, top to
bottom.</li><
li>All non-null properties of each exception.</li><li>The stack
trace <em>at the deepest
level</em>.</li><li>Key <strong>request</strong> properties, header,
attributes, and
parameters.</li><li>Key <strong>session</strong><em> </em>propertes</li><li>A
break down of the <em>thread</em> in your application</li><li>A listing
of all JVM System properties</li></ul><h2
id="RuntimeExceptions-DetailedExceptionReportFiles">Detailed Exception Report
Files</h2><p>In addition, Tapestry will write a text file for the exception
with a similar level of detail. The default location for the detailed exception
report files is a relative directory <em>build/exceptions</em>. You can
configure the location by setting <a class="external-link"
href="http://tapestry.apache.org/current/apidocs/org/apache/tapestry5/SymbolConstants.html#EXCEPTION_REPORTS_DIR";>SymbolConstants.EXCEPTION_REPORTS_DIR</a>.</p><p>If
you want to turn off the writing of detailed exception reports files to th
e file system, you can add the following to your application module (usually
AppModule.java):</p><div class="code panel pdl" style="border-width: 1px;"><div
class="codeHeader panelHeader pdl" style="border-bottom-width:
1px;"><b>AppModule.java (partial)</b></div><div class="codeContent panelContent
pdl">
+<pre class="brush: java; gutter: false; theme: Default"
style="font-size:12px;"> /**
+ * By default, Tapestry's ExceptionReporter implementation writes verbose
text files to the
+ * "build/exceptions" directory. This replaces that implementation with
one that does nothing.
+ * (The exceptions still get logged elsewhere.)
+ */
+ @Decorate(serviceInterface = ExceptionReporter.class)
+ public static ExceptionReporter preventExceptionFileWriting(final
ExceptionReporter exceptionReporter) {
+ return new ExceptionReporter() {
+ @Override
+ public void reportException(Throwable exception) {
+ }
+ };
+ }</pre>
+</div></div><h2 id="RuntimeExceptions-AjaxDetailedExceptionReports">Ajax
Detailed Exception Reports</h2><p>A similar detailed exception report is also
built-in to Tapestry's Ajax support. When an Ajax request fails, Tapestry's
client-side code will create an <iframe> to present this same
information:</p><p><span class="confluence-embedded-file-wrapper
confluence-embedded-manual-size"><img class="confluence-embedded-image
confluence-content-image-border" height="359" width="500"
src="runtime-exceptions.data/Exception_Ajax.png"></span></p><h2
id="RuntimeExceptions-OverridingtheHandlingofSpecificExceptions">Overriding the
Handling of Specific Exceptions</h2><p>In production, you may want to <a
href="overriding-exception-reporting.html">override the exception report
page</a> (even if you keep the text file output). However, Tapestry's (from
version 5.4) default exception reporter also allows you to handle specific
exception types in a pre-determined manner, similar to how servlet
spec's standard error-page/exception-type configuration option allows you to
map exception types to URLs. At times, it's simpler to just catch exceptions at
the outermost layer of your application instead of carrying a typed exception
through multiple layers of abstractions just so you could show a sensible error
message to the user, especially if you can't do anything more clever about it
anyway. Exception type mapping in Tapestry is much more powerful than what the
servlet spec dictates. If your email service or an external payment service
goes down, you can't do much more than display an error message to the user, so
why would you need to implement separate pages for each exception? Often, it'd
be nicer if you could just reuse the page template for any fatal exception and
simply display a different error message. In addition to contributing handlers
for specific types of exceptions, you may also provide context for rendering
the same error page template with a different output.<
/p><p>You can contribute an error page, mapping it to an exception
type:</p><div class="code panel pdl" style="border-width: 1px;"><div
class="codeHeader panelHeader pdl" style="border-bottom-width:
1px;"><b>AppModule.java (partial)</b></div><div class="codeContent panelContent
pdl">
<pre class="brush: java; gutter: false; theme: Default"
style="font-size:12px;"> public void
contributeExceptionHandler(MappedConfiguration<Class, Class>
configuration) {
configuration.add(SmtpNotRespondingException.class,
ServiceFailure.class);
}</pre>
-</div></div><p>If a simple exception type to page mapping doesn't do it for
you, you can also contribute a custom handler for that particular exception
type. An <em>ExceptionHandlerAssistant</em> can contain arbitrarily complex
logic for handling a specific exception type and use other Tapestry services.
If <em>ExceptionHandlerAssistant.handleRequestException(Throwable exception,
List<Object> exceptionContext)</em> returns an Object representing an URL
the main handler will issue a redirect to that URL. It's valid to return either
a String, a Link or a Class; the last case implies a page class. If the
<em>ExceptionHandlerAssistant</em> returns null, it's assumed that the
assistant has independently handled the exception. You can either contribute an
instance of an <em>ExceptionHandlerAssistant</em> or a class that implements
<em>ExceptionHandlerAssistant</em>. Below, we contribute an instance handling
<em>ServiceException</em>s:</p><div class="code panel pdl" style="border-wid
th: 1px;"><div class="codeContent panelContent pdl">
-<pre class="brush: java; gutter: false; theme: Default"
style="font-size:12px;"> public void
contributeExceptionHandler(OperationQueue
-operationQueue, MappedConfiguration<Class, Class> configuration) {
+</div></div><p>If a simple exception type to page mapping doesn't do it for
you, you can also contribute a custom handler for that particular exception
type. An <em>ExceptionHandlerAssistant</em> can contain arbitrarily complex
logic for handling a specific exception type and use other Tapestry services.
If <em>ExceptionHandlerAssistant.handleRequestException(Throwable exception,
List<Object> exceptionContext)</em> returns an Object representing an URL
the main handler will issue a redirect to that URL. It's valid to return either
a String, a Link or a Class; the last case implies a page class. If the
<em>ExceptionHandlerAssistant</em> returns null, it's assumed that the
assistant has independently handled the exception. You can either contribute an
instance of an <em>ExceptionHandlerAssistant</em> or a class that implements
<em>ExceptionHandlerAssistant</em>. Below, we contribute an instance handling
<em>ServiceException</em>s:</p><div class="code panel pdl" style="border-wid
th: 1px;"><div class="codeHeader panelHeader pdl" style="border-bottom-width:
1px;"><b>AppModule.java (partial)</b></div><div class="codeContent panelContent
pdl">
+<pre class="brush: java; gutter: false; theme: Default"
style="font-size:12px;"> public void
contributeExceptionHandler(OperationQueue operationQueue,
MappedConfiguration<Class, Class> configuration) {
final ExceptionHandlerAssistant assistant = new
ExceptionHandlerAssistant() {
@Override
public Object handleRequestException(Throwable exception,
List<Object> exceptionContext) throws IOException {
@@ -95,11 +157,11 @@ operationQueue, MappedConfiguration<C
};
configuration.add(ServiceException.class, assistant);
}</pre>
-</div></div><p>You can also specify context for the exception page. For
generic exceptions, the context is taken from the exception class name minus
the word "Exception" in case that's how the class name ends. For example, you
have a following class:</p><div class="code panel pdl" style="border-width:
1px;"><div class="codeContent panelContent pdl">
+</div></div><p>You can also specify context for the exception page. For
generic exceptions, the context is taken from the exception class name minus
the word "Exception" in case that's how the class name ends. For example, you
have a following class:</p><div class="code panel pdl" style="border-width:
1px;"><div class="codeHeader panelHeader pdl" style="border-bottom-width:
1px;"><b>SmtpNotResponding.java</b></div><div class="codeContent panelContent
pdl">
<pre class="brush: java; gutter: false; theme: Default"
style="font-size:12px;">public class SmtpNotRespondingException extends
RuntimeException {
 ...
}</pre>
-</div></div><p>If an <em>SmtpNotRespondingException</em> is thrown during an
action request, user is directed to <em>ServiceFailure</em> page with a String
context smtpnotresponding (i.e. to URL
<strong>/servicefailure/smtpnotresponding</strong>). The contributed exception
handling works both for regular action requests and ajax action requests. In
the latter case, the module will use Javascript to redirect to the error page.
If the exception thrown is not one of the contributed types, the exception is
handled like any other exception, as explained above.</p><p>If your
custom-handled exception implements the interface
<em>org.apache.tapestry5.ContextAwareException</em> you can fully specify the
context for the error page. For example, you could implement a following
Exception class:</p><div class="code panel pdl" style="border-width: 1px;"><div
class="codeContent panelContent pdl">
+</div></div><p>If an <em>SmtpNotRespondingException</em> is thrown during an
action request, user is directed to <em>ServiceFailure</em> page with a String
context smtpnotresponding (i.e. to URL
<strong>/servicefailure/smtpnotresponding</strong>). The contributed exception
handling works both for regular action requests and ajax action requests. In
the latter case, the module will use Javascript to redirect to the error page.
If the exception thrown is not one of the contributed types, the exception is
handled like any other exception, as explained above.</p><p>If your
custom-handled exception implements the interface
<em>org.apache.tapestry5.ContextAwareException</em> you can fully specify the
context for the error page. For example, you could implement a following
Exception class:</p><div class="code panel pdl" style="border-width: 1px;"><div
class="codeHeader panelHeader pdl" style="border-bottom-width:
1px;"><b>SmtpNotRespondingException.java</b></div><div class="codeContent pan
elContent pdl">
<pre class="brush: java; gutter: false; theme: Default"
style="font-size:12px;"> public class SmtpNotRespondingException extends
RuntimeException implements ContextAwareException {
private Object[] context;
public EmailServiceException(Object[] context) {
