public class ReloadingWicketFilter extends WicketFilter
WicketFilter
that reloads the web applications when classes are modified. In order
to monitor changes to your own classes, subclass ReloadingWicketFilter
and use include
and exclude patterns using wildcards. And in web.xml, point to your custom
ReloadingWicketFilter
instead of the original WicketFilter
.
The built-in patterns are:
ReloadingClassLoader.excludePattern("org.apache.wicket.*"); ReloadingClassLoader.includePattern("org.apache.wicket.examples.*");
Example. Defining custom patterns
public class MyReloadingFilter extends ReloadingWicketFilter { static { ReloadingClassLoader.includePattern("com.company.*"); ReloadingClassLoader.excludePattern("com.company.spring.beans.*"); ReloadingClassLoader.includePattern("some.other.package.with.wicket.components.*"); } }
NOTE. If you wish to reload com.company.search.Form, you have to make sure to include all classes that reference com.company.search.Form. In particular, if it is referenced in com.company.Application, you will also have to include the latter. And this is viral, as for every class you include, you must check that all classes that reference it are also included.
It is also possible to add an extra URL to watch for changes using
ReloadingClassLoader.addLocation() . By default, all the URLs returned by the parent
class loader (ie all URL
returned by ClassLoader.getResources(String)
with empty
String
) are registered.
Important. It can be quite tricky to setup the reloading mechanism correctly. Here are the general guidelines:
WebApplication.init()
method. Native JDK object serialization will break the reloading
mechanism when navigating in the browser's history.Session
from the the reloading
classloader, because this is the only object that remains across application restartsBe sure to carefully read the following information if you also use Spring:
When using org.apache.wicket.spring.SpringWebApplicationFactory, the application must be a bean with "prototype" scope and the "applicationBean" init parameter must be explicitly set, otherwise the reloading mechanism won't be able to recreate the application.
WARNING. Be careful that when using Spring or other component managers, you will get ClassCastException if a given class is loaded two times, one time by the normal classloader, and another time by the reloading classloader. You need to ensure that your Spring beans are properly excluded from the reloading class loader and that only the Wicket components are included. When getting a cryptic error with regard to class loading, class instantiation or class comparison, first disable the reloading class loader to rule out the possibility of a classloader conflict. Please keep in mind that two classes are equal if and only if they have the same name and are loaded in the same classloader. Same goes for errors like LinkageError: Class FooBar violates loader constraints, better be safe and disable the reloading feature.
WicketFilter
APP_FACT_PARAM, FILTER_MAPPING_PARAM, IGNORE_PATHS_PARAM
Constructor and Description |
---|
ReloadingWicketFilter()
Instantiate the reloading class loader
|
Modifier and Type | Method and Description |
---|---|
protected ClassLoader |
getClassLoader() |
void |
init(boolean isServlet,
javax.servlet.FilterConfig filterConfig)
Servlets and Filters are treated essentially the same with Wicket.
|
checkIfRedirectRequired, destroy, doFilter, getApplication, getApplicationFactory, getFilterConfig, getFilterPath, getFilterPath, getFilterPathFromAnnotation, getFilterPathFromConfig, getFilterPathFromWebXml, getRelativePath, init, processRequestCycle, setFilterPath
public ReloadingWicketFilter()
protected ClassLoader getClassLoader()
getClassLoader
in class WicketFilter
WicketFilter.getClassLoader()
public void init(boolean isServlet, javax.servlet.FilterConfig filterConfig) throws javax.servlet.ServletException
WicketFilter
init
in class WicketFilter
isServlet
- True if Servlet, false if Filterjavax.servlet.ServletException
WicketFilter.init(boolean, javax.servlet.FilterConfig)
Copyright © 2006–2022 Apache Software Foundation. All rights reserved.