org.mmbase.servlet
Class MMBaseServlet

java.lang.Object
  javax.servlet.GenericServlet
      javax.servlet.http.HttpServlet
          org.mmbase.servlet.MMBaseServlet

All Implemented Interfaces:

org.mmbase.servlet.MMBaseStarter, java.io.Serializable, javax.servlet.Servlet, javax.servlet.ServletConfig

Direct Known Subclasses:

BridgeServlet, DoveServlet, JamesServlet, RMIHandlerServlet

public class MMBaseServlet

extends javax.servlet.http.HttpServlet

implements org.mmbase.servlet.MMBaseStarter

MMBaseServlet is a base class for other MMBase servlets (like ImageServlet). Its main goal is to store a MMBase instance for all its descendants, but it can also be used as a serlvet itself, to show MMBase version information.

Since:

MMBase-1.6

Version:

$Id: MMBaseServlet.java,v 1.29 2004/03/16 14:38:38 michiel Exp $

Author:

Michiel Meeuwissen

See Also:

Serialized Form

Field Summary

protected static MMBase

mmbase

Constructor Summary

MMBaseServlet()

Method Summary

protected static void	associateMapping(java.lang.String function, java.lang.String servletMapping, java.lang.Integer priority) Associate a given servletmapping with the given function.
protected void	decRefCount(javax.servlet.http.HttpServletRequest req) Decrease the reference count of the servlet
void	destroy()
void	doGet(javax.servlet.http.HttpServletRequest req, javax.servlet.http.HttpServletResponse res) Serves MMBase version information.
protected java.util.Map	getAssociations() On default, servlets are not associated with any function.
MMBase	getMMBase() Returns the currently set MMBase object.
protected static java.lang.String	getRequestURL(javax.servlet.http.HttpServletRequest req) Return URI with QueryString appended
static java.lang.String	getServletByAssociation(java.lang.String function) Gets the name of the servlet that performs actions associated with the the given function.
static javax.servlet.http.HttpServlet	getServletByMapping(java.lang.String mapping) Gets the servlet that belongs to the given mapping
java.lang.String	getServletInfo() Returns information about this servlet.
static java.util.List	getServletMappings(java.lang.String servletName) Gets all the mappings for a given servlet.
static java.util.List	getServletMappingsByAssociation(java.lang.String function) Gets all the mappings for a given association.
protected void	incRefCount(javax.servlet.http.HttpServletRequest req) Increase the reference count of the servlet (for debugging) and send running servlets to log once every 32 requests
void	init() The init of an MMBaseServlet checks if MMBase is running.
void	service(javax.servlet.http.HttpServletRequest req, javax.servlet.http.HttpServletResponse res) The service method is extended with calls for the refCount functionality (for performance related debugging).
void	setInitException(javax.servlet.ServletException e) If something went wrong (an exception occured), the caller may is informed by a call to this method.
void	setMMBase(MMBase mmb) Set MMBase object after initializion, in the caller.

Methods inherited from class javax.servlet.http.HttpServlet

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

Methods inherited from class javax.servlet.GenericServlet

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

Methods inherited from class java.lang.Object

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

Field Detail

mmbase

protected static MMBase mmbase

Constructor Detail

MMBaseServlet

public MMBaseServlet()

Method Detail

getAssociations

protected java.util.Map getAssociations()

On default, servlets are not associated with any function. This function is called in the init method.

Returns:

A map of Strings (function) -> Integer (priority). Never null.

getMMBase

public MMBase getMMBase()

Description copied from interface: org.mmbase.servlet.MMBaseStarter

Returns the currently set MMBase object.

Specified by:

getMMBase in interface org.mmbase.servlet.MMBaseStarter

Returns:

the MMBase instance or null.

setMMBase

public void setMMBase(MMBase mmb)

Description copied from interface: org.mmbase.servlet.MMBaseStarter

Set MMBase object after initializion, in the caller.

Specified by:

setMMBase in interface org.mmbase.servlet.MMBaseStarter

setInitException

public void setInitException(javax.servlet.ServletException e)

Description copied from interface: org.mmbase.servlet.MMBaseStarter

If something went wrong (an exception occured), the caller may is informed by a call to this method. (It may ignore it).

Specified by:

setInitException in interface org.mmbase.servlet.MMBaseStarter

init

public void init()
          throws javax.servlet.ServletException

The init of an MMBaseServlet checks if MMBase is running. It not then it is started.

Throws:

javax.servlet.ServletException

getServletByMapping

public static javax.servlet.http.HttpServlet getServletByMapping(java.lang.String mapping)

Gets the servlet that belongs to the given mapping

Parameters:

mapping - the mapping used to access the servlet

Returns:

the Servlet that handles the mapping

getServletMappings

public static java.util.List getServletMappings(java.lang.String servletName)

Gets all the mappings for a given servlet. So, this is a method to obtain info from web.xml.

Parameters:

servletName - the name of the servlet

Returns:

an unmodifiable list of servlet mappings for this servlet

getServletMappingsByAssociation

public static java.util.List getServletMappingsByAssociation(java.lang.String function)

Gets all the mappings for a given association. Use this to find out how to call a servlet to handle a certain type of operation or data (i.e 'images', 'attachments').

Parameters:

function - the function that identifies the type of association

Returns:

an unmodifiable list of servlet mappings associated with the function

getServletByAssociation

public static java.lang.String getServletByAssociation(java.lang.String function)

Gets the name of the servlet that performs actions associated with the the given function. Use this to find a servlet to handle a certain type of operation or data (i.e 'imageservlet', 'myimageservlet', 'images');

Parameters:

function - the function that identifies the type of association

Returns:

the name of the servlet associated with the function, or null if there is none

associateMapping

protected static void associateMapping(java.lang.String function,
                                       java.lang.String servletMapping,
                                       java.lang.Integer priority)

Associate a given servletmapping with the given function. Use this to set a servletmapping to call for a certain type of operation or data (i.e 'image-processing'); For now, only one servletmapping can be registered.

Parameters:

function - the function that identifies the type of association

servletMapping - mapping of the servlet to associate with the function

priority - priority of this association, the association only occurs if no servlet or servletmapping with higher priority for the same function is present already

doGet

public void doGet(javax.servlet.http.HttpServletRequest req,
                  javax.servlet.http.HttpServletResponse res)
           throws javax.servlet.ServletException,
                  java.io.IOException

Serves MMBase version information. This doesn't do much usefull yet, but one could image lots of cool stuff here. Any other MMBase servlet will probably override this method.

Throws:

javax.servlet.ServletException

java.io.IOException

service

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

The service method is extended with calls for the refCount functionality (for performance related debugging). So you can simply override doGet in extension classes, and this stays working, without having to think about it.

Throws:

javax.servlet.ServletException

java.io.IOException

getServletInfo

public java.lang.String getServletInfo()

Returns information about this servlet. Don't forget to override it.

Specified by:

getServletInfo in interface javax.servlet.Servlet

getRequestURL

protected static java.lang.String getRequestURL(javax.servlet.http.HttpServletRequest req)

Return URI with QueryString appended

Parameters:

req - The HttpServletRequest.

decRefCount

protected void decRefCount(javax.servlet.http.HttpServletRequest req)

Decrease the reference count of the servlet

Parameters:

req - The HttpServletRequest.

incRefCount

protected void incRefCount(javax.servlet.http.HttpServletRequest req)

Increase the reference count of the servlet (for debugging) and send running servlets to log once every 32 requests

Parameters:

req - The HttpServletRequest.

Warning: Scope will be changed to:

private

destroy

public void destroy()

Specified by:

destroy in interface javax.servlet.Servlet