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

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

All Implemented Interfaces:

Filter

Direct Known Subclasses:

GzipFilter, JavaScriptWritelnFilter, XMLPostProcessingFilter, XMLValidationFilter

public abstract class FilterCore
extends Object
implements Filter

Abstract class that contains core methods common to Servlet Filters. Implementation note: Servlet Filters only get instatiated once and live for the lifetime of the application.

Version:

$Id: FilterCore.java,v 1.2 2009/03/20 23:34:01 jweather Exp $

Author:

John Weatherley

Constructor Summary

FilterCore()

Method Summary

protected static String	getDateStamp() Return a string for the current time and date, sutiable for display in log files and output to standout:
protected boolean	handleErrorCodes(HttpServletResponse res, CharArrayWrapper wrapper) Handles http errors (not yet implemented).
static boolean	isGzipSupported(HttpServletRequest req) Determines whether the client that made the request can accept a gzip response.
protected void	prtlnCore(String s) Output a line of text to standard out, with datestamp, if debug is set to true.
protected void	writeGzipResponse(char[] content, HttpServletResponse res) Writes the response content to the client using gzip compression.
protected void	writeRegularResponse(StringBuffer content, HttpServletResponse res) Writes the response to the OutputStream without gzipping it, for use if the client can not accept a gzip response.

Methods inherited from class java.lang.Object

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

Methods inherited from interface javax.servlet.Filter

destroy, doFilter, init

Constructor Detail

FilterCore

public FilterCore()

Method Detail

writeGzipResponse

protected final void writeGzipResponse(char[] content,
                                       HttpServletResponse res)
                                throws IOException

Writes the response content to the client using gzip compression. Before using this method, make sure the client can accespt gzip content via the isGzipSupported(javax.servlet.http.HttpServletRequest) method.

Note: you must set the content encoding type to gzip using the method
response.setHeader("Content-Encoding", "gzip"); prior to calling chain.doFilter() method.

Parameters:

content - The content to sent to the client in gzip format

res - The response object

Throws:

IOException - If IO Error occurs

writeRegularResponse

protected final void writeRegularResponse(StringBuffer content,
                                          HttpServletResponse res)
                                   throws IOException

Writes the response to the OutputStream without gzipping it, for use if the client can not accept a gzip response.

Parameters:

content - The content to setd

res - The response

Throws:

IOException - If error

isGzipSupported

public static final boolean isGzipSupported(HttpServletRequest req)

Determines whether the client that made the request can accept a gzip response.

Parameters:

req - The request

Returns:

True if the client can accept gzip content

handleErrorCodes

protected final boolean handleErrorCodes(HttpServletResponse res,
                                         CharArrayWrapper wrapper)
                                  throws IOException

Handles http errors (not yet implemented).

Parameters:

res - The response

wrapper - The wrapper

Returns:

True if an http error occured and is being handled here

Throws:

IOException - If error processing

getDateStamp

protected static final String getDateStamp()

Return a string for the current time and date, sutiable for display in log files and output to standout:

Returns:

The dateStamp value

prtlnCore

protected final void prtlnCore(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.