javawebparts.filter
Class AppAvailabilityFilter

java.lang.Object
  |
  +--javawebparts.filter.AppAvailabilityFilter

All Implemented Interfaces:

javax.servlet.Filter

public class AppAvailabilityFilter

extends java.lang.Object

implements javax.servlet.Filter

This filter allows for defining a time window for each day of the week during which the application is available. It allows for including or excluding paths from filter functionality. It also also allows for bypassing filter functionality based on an application-defined criteria. It allows for forwarding or redirecting to a defined page when the application is not available.

Init parameters are:

• pathSpec - Either "include" or "exclude". This determines whether the list of paths in the pathList parameter is a list of paths to include in filter functionality, or a list of paths to exclude. Required: No. Default: None.



• pathList - This is a comma-separated list of paths, which can use asterisk for wildcard support, that denotes either paths to include or exclude from the functioning of this filter (depending on what pathSpec is set to). The paths ARE case-senitive! There is no limit to how many items can be specified, although for performance reasons a developer will probably want to specify as few as possible to get the job done (each requested path is matched via regex). Note also that you are of course still required to specify a path for the filter itself as per the servlet spec. This parameter however, together with pathSpec, gives you more control and flexibility than that setting alone. Required: No. Default: None.
  
  General note on pathSpec and pathList: If pathSpec is not specified but pathList IS, then 'exclude' is assumed for pathSpec. If pathSpec is specified by pathList IS NOT, then the filter WILL NEVER EXECUTE (this is technically a misconfiguration). If NEITHER is defined then the generic filter mapping will be in effect only.



• bypassCheckClass - This is a class you can optionally provide that must implement the AppAvailabilityBypassCheck interface, to allow for the capability to override the function of this filter. For instance, you may want a particular user to always be allowed in. By supplying this class, you can do that in whatever fashion is appropriate for your application (i.e., maybe you need to grab a particular parameter from request and look up the user in a database). Required: Yes. Default: None.



• redirectTo - The URL to redirect to if the app is not available. You can either redirect to this URL or forward to it, but not both. Required: Yes (either this or forwardTo). Default: None.



• forwardTo - The URL to forward to if the app is not available. You can either redirect to this URL or forward to it, but not both. Required: Yes (either this or redirectTo). Default: None.



• monday - The time range within which the application is available on a Monday. Required: Yes. Default: None.



• tuesday - The time range within which the application is available on a Tuesday. Required: Yes. Default: None.



• wednesday - The time range within which the application is available on a Wednesday. Required: Yes. Default: None.



• thursday - The time range within which the application is available on a Thursday. Required: Yes. Default: None.



• friday - The time range within which the application is available on a Friday. Required: Yes. Default: None.



• saturday - The time range within which the application is available on a Saturday. Required: Yes. Default: None.



• sunday - The time range within which the application is available on a Sunday. Required: Yes. Default: None.


General notes on the time ranges... the times are specified in 24-hour format and the value of the parameter for each day is in the form 8888-9999, where 8888 is the start time and 999 is the end time. Start and end times CAN span days, i.e., you can define that the application is available from 11pm on Friday to 6am on Saturday (by setting friday to 2300-0600).

Example configuration in web.xml:

<filter>
<filter-name>AppAvailabilityFilter</filter-name>
<filter-class>javawebparts.filter. AppAvailabilityFilter</filter-class>
<init-param>
<param-name>pathSpec</param-name>
<param-value>include</param-value>
</init-param>
<init-param>
<param-name>pathList</param-name>
<param-value>*‍/AAFTestTarget.jsp </param-value>
</init-param>
<init-param>
<param-name>monday</param-name>
<param-value>0600-2359</param-value>
</init-param>
<init-param>
<param-name>tuesday</param-name>
<param-value>0600-2359</param-value>
</init-param>
<init-param>
<param-name>wednesday</param-name>
<param-value>0600-2359</param-value>
</init-param>
<init-param>
<param-name>thursday</param-name>
<param-value>0600-2359</param-value>
</init-param>
<init-param>
<param-name>friday</param-name>
<param-value>0600-2359</param-value>
</init-param>
<init-param>
<param-name>saturday</param-name>
<param-value>0600-2359</param-value>
</init-param>
<init-param>
<param-name>sunday</param-name>
<param-value>0600-2359</param-value>
</init-param>
<init-param>
<param-name>redirectTo</param-name>
<param-value>AAFReject.jsp< /param-value>
</init-param>
<init-param>
<param-name>bypassCheckClass< /param-name>
<param-value>javawebparts.sampleapp. AAFBypassCheck</param-value>
</init-param>
</filter>

<filter-mapping>
<filter-name>AppAvailabilityFilter</filter-name>
<url-pattern>/*</url-pattern>
</filter-mapping>

Author:

Frank W. Zammetti.

Field Summary

private java.lang.String	bypassCheckClass A class that will be used to allow for bypassing this filter.
private java.lang.String	forwardTo A path to forward to when access is denied.
private int	fridayEnd The end of the time window the app is available during on Friday.
private int	fridayStart The start of the time window the app is available during on Friday.
private static org.apache.commons.logging.Log	log Log instance.
private int	mondayEnd The end of the time window the app is available during on Monday.
private int	mondayStart The start of the time window the app is available during on Monday.
private java.util.ArrayList	pathList List of paths for filter functionality determination.
private java.lang.String	pathSpec Whether pathList includes or excludes.
private java.lang.String	redirectTo A path to redirect to when access is denied.
private int	saturdayEnd The end of the time window the app is available during on Saturday.
private int	saturdayStart The start of the time window the app is available during on Saturday.
private int	sundayEnd The end of the time window the app is available during on Sunday.
private int	sundayStart The start of the time window the app is available during on Sunday.
private int	thursdayEnd The end of the time window the app is available during on Thursday.
private int	thursdayStart The start of the time window the app is available during on Thursday.
private static int	TIME_END Flag to retrieve end time for a date.
private static int	TIME_START Flag to retrieve start time for a date.
private int	tuesdayEnd The end of the time window the app is available during on Tuesday.
private int	tuesdayStart The start of the time window the app is available during on Tuesday.
private int	wednesdayEnd The end of the time window the app is available during on Wednesday.
private int	wednesdayStart The start of the time window the app is available during on Wednesday.

Constructor Summary

AppAvailabilityFilter()

Method Summary

void	destroy() Destroy.
void	doFilter(javax.servlet.ServletRequest request, javax.servlet.ServletResponse response, javax.servlet.FilterChain filterChain) Do filter's work.
private int	getDayStartEnd(javax.servlet.FilterConfig filterConfig, java.lang.String day, int whatPart) Retrieves the start or stop time, as specified, from a time range in the form 8888-9999 where 8888 is the start time in 24-hour time and 9999 is the end time in 24-hour time.
void	init(javax.servlet.FilterConfig filterConfig) Initialize this filter.
private boolean	isAppAvailable() This is called to determine if the app is available.
private boolean	isTimeInRange(int rangeStart, int rangeEnd, int timeToCheck) This method checks if a given 24-hour time is within a given 24-hour time.

Methods inherited from class java.lang.Object

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

Field Detail

log

private static org.apache.commons.logging.Log log

Log instance.

TIME_START

private static final int TIME_START

Flag to retrieve start time for a date.

See Also:

Constant Field Values

TIME_END

private static final int TIME_END

Flag to retrieve end time for a date.

See Also:

Constant Field Values

pathSpec

private java.lang.String pathSpec

Whether pathList includes or excludes.

pathList

private java.util.ArrayList pathList

List of paths for filter functionality determination.

redirectTo

private java.lang.String redirectTo

A path to redirect to when access is denied.

forwardTo

private java.lang.String forwardTo

A path to forward to when access is denied.

bypassCheckClass

private java.lang.String bypassCheckClass

A class that will be used to allow for bypassing this filter.

mondayStart

private int mondayStart

The start of the time window the app is available during on Monday.

mondayEnd

private int mondayEnd

The end of the time window the app is available during on Monday.

tuesdayStart

private int tuesdayStart

The start of the time window the app is available during on Tuesday.

tuesdayEnd

private int tuesdayEnd

The end of the time window the app is available during on Tuesday.

wednesdayStart

private int wednesdayStart

The start of the time window the app is available during on Wednesday.

wednesdayEnd

private int wednesdayEnd

The end of the time window the app is available during on Wednesday.

thursdayStart

private int thursdayStart

The start of the time window the app is available during on Thursday.

thursdayEnd

private int thursdayEnd

The end of the time window the app is available during on Thursday.

fridayStart

private int fridayStart

The start of the time window the app is available during on Friday.

fridayEnd

private int fridayEnd

The end of the time window the app is available during on Friday.

saturdayStart

private int saturdayStart

The start of the time window the app is available during on Saturday.

saturdayEnd

private int saturdayEnd

The end of the time window the app is available during on Saturday.

sundayStart

private int sundayStart

The start of the time window the app is available during on Sunday.

sundayEnd

private int sundayEnd

The end of the time window the app is available during on Sunday.

Constructor Detail

AppAvailabilityFilter

public AppAvailabilityFilter()

Method Detail

destroy

public void destroy()

Destroy.

Specified by:

destroy in interface javax.servlet.Filter

init

public void init(javax.servlet.FilterConfig filterConfig)
          throws javax.servlet.ServletException

Initialize this filter.

Specified by:

init in interface javax.servlet.Filter

Parameters:

filterConfig - The configuration information for this filter.

Throws:

javax.servlet.ServletException - ServletException.

getDayStartEnd

private int getDayStartEnd(javax.servlet.FilterConfig filterConfig,
                           java.lang.String day,
                           int whatPart)
                    throws javax.servlet.ServletException

Retrieves the start or stop time, as specified, from a time range in the form 8888-9999 where 8888 is the start time in 24-hour time and 9999 is the end time in 24-hour time.

Parameters:

filterConfig - The configuration information for this filter.

day - What day of the week to retrieve.

whatPart - Which part of the range to return (start or end).

Returns:

The start or stop time, as specified, as an int (24-hour form).

Throws:

javax.servlet.ServletException - If any problems occur, this gets thrown.

doFilter

public void doFilter(javax.servlet.ServletRequest request,
                     javax.servlet.ServletResponse response,
                     javax.servlet.FilterChain filterChain)
              throws javax.servlet.ServletException,
                     java.io.IOException

Do filter's work.

Specified by:

doFilter in interface javax.servlet.Filter

Parameters:

request - The current request object.

response - The current response object.

filterChain - The current filter chain.

Throws:

javax.servlet.ServletException - ServletException.

java.io.IOException - IOException.

isAppAvailable

private boolean isAppAvailable()

This is called to determine if the app is available. It does this by determining if the current time on the server is within the availability window configured for the current day of the week.

Returns:

True if the app is available, false if not.

isTimeInRange

private boolean isTimeInRange(int rangeStart,
                              int rangeEnd,
                              int timeToCheck)

This method checks if a given 24-hour time is within a given 24-hour time. Note that this should properly handle ranges that span days, i.e., if the start time is 2000 and the end time is 800 (8pm-8am the following day), this should still work fine.

Parameters:

rangeStart - Beginning of range.

rangeEnd - End of range.

timeToCheck - The time to check against the range.

Returns:

True if the checked time is within the range, false if it isn't.