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java.lang.Object org.apache.commons.chain.web.ChainListener
public class ChainListener
ServletContextListener
that automatically
scans chain configuration files in the current web application at
startup time, and exposes the result in a Catalog
under a
specified servlet context attribute. The following context init
parameters are utilized:
ClassLoader.getResource()
calls. If not specified,
no class loader resources will be loaded.Catalog
will be created or updated.
If not specified, it is expected that parsed resources will
contain <catalog>
elements (which will
cause registration of the created Catalog
s into
the CatalogFactory
for this application, and no
servet context attribute will be created.
NOTE - This parameter is deprecated.
RuleSet
implementation to use for parsing configuration resources (this
class must have a public zero-args constructor). If not defined,
the standard RuleSet
implementation will be used.When a web application that has configured this listener is
started, it will acquire the Catalog
under the specified servlet
context attribute key, creating a new one if there is none already there.
This Catalog
will then be populated by scanning configuration
resources from the following sources (loaded in this order):
META-INF/chain-config.xml
resource found in a JAR file in /WEB-INF/lib
.ClassLoader.getResource()
).ServetContext.getResource()
).If no attribute key is specified, on the other hand, parsed configuration
resources are expected to contain <catalog>
elements,
and the catalogs will be registered with the CatalogFactory
for this web application.
This class requires Servlet 2.3 or later. If you are running on
Servlet 2.2 system, consider using ChainServlet
instead.
Note that ChainServlet
uses parameters of the
same names, but they are servlet init parameters instead
of context init parameters. Because of this, you can use
both facilities in the same application, if desired.
Field Summary | |
---|---|
static String |
CONFIG_ATTR
The name of the context init parameter containing the name of the servlet context attribute under which our resulting Catalog
will be stored. |
static String |
CONFIG_CLASS_RESOURCE
The name of the context init parameter containing a comma-delimited list of class loader resources to be scanned. |
static String |
CONFIG_WEB_RESOURCE
The name of the context init parameter containing a comma-delimited list of web applicaton resources to be scanned. |
static String |
RULE_SET
The name of the context init parameter containing the fully qualified class name of the RuleSet implementation
for configuring our ConfigParser . |
Constructor Summary | |
---|---|
ChainListener()
|
Method Summary | |
---|---|
void |
contextDestroyed(ServletContextEvent event)
Remove the configured Catalog from the servlet context
attributes for this web application. |
void |
contextInitialized(ServletContextEvent event)
Scan the required chain configuration resources, assemble the configured chains into a Catalog , and expose it as a
servlet context attribute under the specified key. |
Methods inherited from class java.lang.Object |
---|
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait |
Field Detail |
---|
public static final String CONFIG_ATTR
The name of the context init parameter containing the name of the
servlet context attribute under which our resulting Catalog
will be stored.
public static final String CONFIG_CLASS_RESOURCE
The name of the context init parameter containing a comma-delimited list of class loader resources to be scanned.
public static final String CONFIG_WEB_RESOURCE
The name of the context init parameter containing a comma-delimited list of web applicaton resources to be scanned.
public static final String RULE_SET
The name of the context init parameter containing the fully
qualified class name of the RuleSet
implementation
for configuring our ConfigParser
.
Constructor Detail |
---|
public ChainListener()
Method Detail |
---|
public void contextDestroyed(ServletContextEvent event)
Remove the configured Catalog
from the servlet context
attributes for this web application.
contextDestroyed
in interface ServletContextListener
event
- ServletContextEvent
to be processedpublic void contextInitialized(ServletContextEvent event)
Scan the required chain configuration resources, assemble the
configured chains into a Catalog
, and expose it as a
servlet context attribute under the specified key.
contextInitialized
in interface ServletContextListener
event
- ServletContextEvent
to be processed
|
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