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

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

All Implemented Interfaces:

Filter

public final class JavaScriptWritelnFilter
extends FilterCore

Converts JSP, servlet, HTML or other output into a JavaScript writeln statement or places it into a JavaScript variable. Activated by specifying a query parameter - if none is supplied, the output is left unchanged (except for Gziping). This Filter may be used to create a JavaScript proxy for conetnt. Gzip compresses the response if the browser supports it.

To use, configure the filter to be activated for the pages you want in your web.xml configuration. Then send a request to the page with the one or more of the following query parameters:

rt=jswl - Instructions the filter to output the content as a document.write( content ); statement
rt=jsvar - Instructs the filter to place the content into a JavaScript variable named 'jsvar'.
jsvarname=myvarname - (optional) When jsvar is used, this instructs the filter to place the ouput into the a variable by the name provided. If not supplied, defaults to 'jsvar'.

Examples:

<script type='text/javascript' src='http://example.org/myPage.jsp?rt=jswl'></script>
<script type='text/javascript' src='http://example.org/myPage.jsp?rt=jsvar&jsvarname=myXml'> </script>

Version:

$Id: JavaScriptWritelnFilter.java,v 1.9 2009/03/20 23:34:01 jweather Exp $

Author:

John Weatherley

Constructor Summary

JavaScriptWritelnFilter()

Method Summary

void	destroy() Destroy is called at application shut-down time.
void	doFilter(ServletRequest request, ServletResponse response, FilterChain chain) Converts the http response into a JavaScript output if parameter rt=jsvar or rt=jswl.
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	setDebugzz(boolean db) Sets the debug attribute of the JavaScriptWritelnFilter object

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

JavaScriptWritelnFilter

public JavaScriptWritelnFilter()

Method Detail

doFilter

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

Converts the http response into a JavaScript output if parameter rt=jsvar or rt=jswl. Gzip compresses the response regardless.

Parameters:

request - The request

response - The response

chain - The chain of Filters

Throws:

ServletException - If error

IOException - If IO error

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 final 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.

setDebugzz

protected final void setDebugzz(boolean db)

Sets the debug attribute of the JavaScriptWritelnFilter object

Parameters:

db - The new debug value