Package org.apache.commons.chain.web.servlet

Class ChainProcessor

java.lang.Object

javax.servlet.GenericServlet

javax.servlet.http.HttpServlet

org.apache.commons.chain.web.ChainServlet

org.apache.commons.chain.web.servlet.ChainProcessor

public class ChainProcessor
extends ChainServlet

Custom subclass of ChainServlet that also dispatches incoming requests to a configurable Command loaded from the specified Catalog.

In addition to the servlet init parameters supported by ChainServlet, this class supports the following additional parameters:

• org.apache.commons.chain.CATALOG - Name of the catalog from which to acquire commands to be executed. If not specified, the default catalog for this application will be used.
• org.apache.commons.chain.COMMAND - Name of the Command (looked up in our configured Catalog used to process all incoming servlet requests. If not specified, defaults to command.

Also, the org.apache.commons.chain.CONFIG_ATTR init parameter is also used to identify the Context attribute under which our configured Catalog will be made available to Commands processing our requests, in addition to its definition of the ServletContext attribute key under which the Catalog is available.

See Also:

Serialized Form

Field Summary

Fields

Modifier and Type	Field	Description
private java.lang.String	attribute	The name of the context attribute under which our Catalog is stored.
private java.lang.String	catalog	The name of the Catalog to retrieve from the CatalogFactory for this application, or null to select the default Catalog.
static java.lang.String	CATALOG	The name of the servlet init parameter containing the name of the Catalog to use for processing incoming requests.
static java.lang.String	CATALOG_DEFAULT	The default request attribute under which we expose the Catalog being used to subordinate Commands.
private java.lang.String	command	The name of the Command to be executed for each incoming request.
static java.lang.String	COMMAND	The name of the servlet init parameter containing the name of the Command (loaded from our configured Catalog to use for processing each incoming request.
private static java.lang.String	COMMAND_DEFAULT	The default command name.

Fields inherited from class org.apache.commons.chain.web.ChainServlet

CONFIG_ATTR, CONFIG_CLASS_RESOURCE, CONFIG_WEB_RESOURCE, RULE_SET

Constructor Summary

Constructors

Constructor	Description
ChainProcessor()

Method Summary

Modifier and Type	Method	Description
void	destroy()	Clean up as this application is shut down.
void	init()	Cache the name of the command we should execute for each request.
void	service(javax.servlet.http.HttpServletRequest request, javax.servlet.http.HttpServletResponse response)	Configure a ServletWebContext for the current request, and pass it to the execute() method of the specified Command, loaded from our configured Catalog.

Methods inherited from class javax.servlet.GenericServlet

getInitParameter, getInitParameterNames, getServletConfig, getServletContext, getServletInfo, getServletName, init, log, log

Methods inherited from class javax.servlet.http.HttpServlet

doDelete, doGet, doHead, doOptions, doPost, doPut, doTrace, getLastModified, service

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

CATALOG

public static final java.lang.String CATALOG

The name of the servlet init parameter containing the name of the Catalog to use for processing incoming requests.

See Also:

Constant Field Values

CATALOG_DEFAULT

public static final java.lang.String CATALOG_DEFAULT

The default request attribute under which we expose the Catalog being used to subordinate Commands.

See Also:

Constant Field Values

COMMAND

public static final java.lang.String COMMAND

The name of the servlet init parameter containing the name of the Command (loaded from our configured Catalog to use for processing each incoming request.

See Also:

Constant Field Values

COMMAND_DEFAULT

private static final java.lang.String COMMAND_DEFAULT

The default command name.

See Also:

Constant Field Values

attribute

private java.lang.String attribute

The name of the context attribute under which our Catalog is stored. This value is also used as the name of the context attribute under which the catalog is exposed to commands. If not specified, we will look up commands in the appropriate Catalog retrieved from our CatalogFactory.

catalog

private java.lang.String catalog

The name of the Catalog to retrieve from the CatalogFactory for this application, or null to select the default Catalog.

command

private java.lang.String command

The name of the Command to be executed for each incoming request.

Constructor Detail

ChainProcessor

public ChainProcessor()

Method Detail

destroy

public void destroy()

Clean up as this application is shut down.

Overrides:

destroy in class ChainServlet

init

public void init()
          throws javax.servlet.ServletException

Cache the name of the command we should execute for each request.

Overrides:

init in class ChainServlet

Throws:

javax.servlet.ServletException - if an initialization error occurs

service

public void service(javax.servlet.http.HttpServletRequest request,
                    javax.servlet.http.HttpServletResponse response)
             throws java.io.IOException,
                    javax.servlet.ServletException

Configure a ServletWebContext for the current request, and pass it to the execute() method of the specified Command, loaded from our configured Catalog.

Overrides:

service in class ChainServlet

Parameters:

request - The request we are processing

response - The response we are creating

Throws:

java.io.IOException - if an input/output error occurs

javax.servlet.ServletException - if a servlet exception occurs