org.dlese.dpc.webapps.servlets.filters
Class XMLPostProcessingFilter

java.lang.Object
  org.dlese.dpc.webapps.servlets.filters.FilterCore
      org.dlese.dpc.webapps.servlets.filters.XMLPostProcessingFilter

All Implemented Interfaces:

Filter

Direct Known Subclasses:

RecordValidationFilter

public class XMLPostProcessingFilter
extends FilterCore

Performs post-processing of an XML stream and gzips the response if supported by the browser. Supported post-processing actions include XML validation, XML transform to localized XML, and XML to JSON serialization.

• To invoke XML validation, pass HTTP request parameter rt=validate.
• To invoke XML transform, pass HTTP request parameter transform=localize (localize only value currently supported).
• To invoke XML to JSON serialization, pass HTTP request parameter output=json and optionally callback=myCallbackFn to wrap the response in a callback function named by the paramater value.

The XML validation is implemented using a servlet response Filter that checks the content for validity against an XML schema or DTD, which must be referenced in the content itself.

The JSON serialization is implemented using the json.org XML serializer and appropriate classes must be included in your classpath. See http://www.json.org/javadoc/ .

Author:

John Weatherley

Constructor Summary

XMLPostProcessingFilter()

Method Summary

void	destroy() Destroy is called at application shut-down time.
void	doFilter(ServletRequest request, ServletResponse response, FilterChain chain) Performs XML post-processing and gzipping of the response.
protected String	getValidationMessage(String xml, ServletRequest request) Validate the provided xml and return a validation message.
void	init(FilterConfig config) Init is called once at application start-up.
protected void	prtln(String s) Output a line of text to standard out, with datestamp, if debug is set to true.
protected void	prtlnErr(String s) Output a line of text to error out, with datestamp.
protected void	setDebugz(boolean db) Sets the debug attribute of the XMLPostProcessingFilter object
protected String	xmlToHtml(String xml) Get html-displayable version of provided xml

Methods inherited from class org.dlese.dpc.webapps.servlets.filters.FilterCore

getDateStamp, handleErrorCodes, isGzipSupported, prtlnCore, writeGzipResponse, writeRegularResponse

Methods inherited from class java.lang.Object

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

Constructor Detail

XMLPostProcessingFilter

public XMLPostProcessingFilter()

Method Detail

doFilter

public final void doFilter(ServletRequest request,
                           ServletResponse response,
                           FilterChain chain)
                    throws ServletException,
                           IOException

Performs XML post-processing and gzipping of the response.

Parameters:

request - The request

response - The response

chain - The chain of Filters

Throws:

ServletException - Iff error

IOException - Iff IO error

getValidationMessage

protected String getValidationMessage(String xml,
                                      ServletRequest request)

Validate the provided xml and return a validation message.

Parameters:

xml - XML string to be validated

Returns:

The validationMessage value or null if xml is valid

xmlToHtml

protected String xmlToHtml(String xml)

Get html-displayable version of provided xml

Parameters:

xml - xml to be displayed as html

Returns:

html as string

init

public void init(FilterConfig config)
          throws ServletException

Init is called once at application start-up.

Parameters:

config - The FilterConfig object that holds the ServletContext and init information.

Throws:

ServletException - If an error occurs

destroy

public void destroy()

Destroy is called at application shut-down time.

prtlnErr

protected final void prtlnErr(String s)

Output a line of text to error out, with datestamp.

Parameters:

s - The text that will be output to error out.

prtln

protected void prtln(String s)

Output a line of text to standard out, with datestamp, if debug is set to true.

Parameters:

s - The String that will be output.

setDebugz

protected final void setDebugz(boolean db)

Sets the debug attribute of the XMLPostProcessingFilter object

Parameters:

db - The new debug value