com.dpslink.base.servlet

Class GoBack

java.lang.Object

javax.servlet.GenericServlet

javax.servlet.http.HttpServlet

com.dpslink.base.servlet.BaseServlet

com.dpslink.base.servlet.GoBack

All Implemented Interfaces:

java.io.Serializable, javax.servlet.Servlet, javax.servlet.ServletConfig

public class GoBack
extends BaseServlet

Processes HTML template back button requests. Reads from the session's servlet history stack and redirects the user to the previously executed servlet. After redirection, the invoking servlet (the servlet associated with the html template from which the back button was clicked) is removed from the stack.

See Also:

Serialized Form

Nested Class Summary

Nested classes/interfaces inherited from class com.dpslink.base.servlet.BaseServlet

BaseServlet.Context

Field Summary

Fields

Modifier and Type	Field and Description
private static long	serialVersionUID The class' serialization version id.

Fields inherited from class com.dpslink.base.servlet.BaseServlet

BROWSER_IE, BROWSER_NN, BROWSER_XX, RESP_NULL, RESP_REDIRECTED, RQST_AJAX, RQST_NULL

Constructor Summary

Constructors

Constructor and Description
GoBack()

Method Summary

Modifier and Type	Method and Description
protected void	createNewSessionImpl(BaseServlet.Context baseCtx) Provides additional application-specific functionality for creating a new session.
void	doGet(javax.servlet.http.HttpServletRequest request, javax.servlet.http.HttpServletResponse response) Handles HTTP GET requests.
protected boolean	editFormFields(BaseServlet.Context baseCtx) Edits the values from the html template's form fields.
protected java.lang.String	getNextURL(BaseServlet.Context baseCtx) Returns the next URL (including parameters) to be processed when this servlet's processing has been successfully completed (no edit errors, etc.).
protected java.lang.String	getTemplateName(BaseServlet.Context baseCtx) Returns the name of the html template file used by the servlet.
protected void	initTemplateDataImpl(BaseServlet.Context baseCtx, org.apache.velocity.VelocityContext vc, boolean cookies) Provides additional application-specific functionality for initializing a new set of Velocity template data.
protected void	readParameters(BaseServlet.Context baseCtx, boolean post) Reads the parameters passed to the servlet via the http request object.
protected void	removeFromStack(BaseServlet.Context ctx) Redirects to the appropriate servlet in the history stack and then removes the servlet from the stack.
protected boolean	requiresLogon(BaseServlet.Context baseCtx) Answers if the servlet requires a valid non-default user in order to continue processing.
protected void	resetFormFields(BaseServlet.Context baseCtx) Resets the values for the html template's form fields.
protected void	setCookieValues(BaseServlet.Context baseCtx) Adds one or more values to the http session cookies.
protected void	setSessionValues(BaseServlet.Context baseCtx) Adds one or more values to the http session object.
protected void	setTemplateData(BaseServlet.Context baseCtx) Sets the various data required by the html template.
protected void	useExistingSessionImpl(BaseServlet.Context baseCtx) Provides additional application-specific functionality for using an existing session.
protected void	writePageImpl(BaseServlet.Context baseCtx) Provides additional application-specific functionality for writing a page.

Methods inherited from class com.dpslink.base.servlet.BaseServlet

confirmSession, createContext, createNewSession, determineBrowser, doPost, getCookie, getInvokerName, getInvokerName, getInvokerParams, getInvokerParams, getInvokerPath, getInvokerPath, getInvokerURL, getPageParams, getPageTitle, getRequestURL, getServletName, getServletName, getServletParams, getServletParams, getServletPath, getServletPath, getServletURL, getServletURL, getTemplateMessage, getTemplateMessage, getTemplateMessage, getTemplateMessage, getTemplateMessage, initTemplateData, isPrintable, isServerTomcat, log, qualifyURL, redirectURL, requestComplete, setP3PCompactPolicy, showSiteError, showSiteError, showSiteError, useExistingSession, writeCookie, writeCookie, writeTempCookie

Methods inherited from class javax.servlet.http.HttpServlet

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

Methods inherited from class javax.servlet.GenericServlet

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

Methods inherited from class java.lang.Object

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

Field Detail

serialVersionUID

private static final long serialVersionUID

The class' serialization version id.

See Also:

Constant Field Values

Constructor Detail

GoBack

public GoBack()

Method Detail

doGet

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

Handles HTTP GET requests. Invoked by the servlet API. Overrides doGet in BaseServlet.

Overrides:

doGet in class BaseServlet

Parameters:

request - (HttpServletRequest) The servlet's incoming request.

response - (HttpServletResponse) The servlet's outgoing response.

Throws:

java.io.IOException - - if an error occurs while processing the request or response.

javax.servlet.ServletException - - if an error occurs while processing the request or response.

createNewSessionImpl

protected void createNewSessionImpl(BaseServlet.Context baseCtx)

Provides additional application-specific functionality for creating a new session. Invoked by the createNewSession method. Overrides createNewSessionImpl in BaseServlet.

Specified by:

createNewSessionImpl in class BaseServlet

Parameters:

baseCtx - (Context) The current servlet context.

initTemplateDataImpl

protected void initTemplateDataImpl(BaseServlet.Context baseCtx,
                                    org.apache.velocity.VelocityContext vc,
                                    boolean cookies)

Provides additional application-specific functionality for initializing a new set of Velocity template data. Invoked by the initTemplateData method. Overrides initTemplateDataImpl in BaseServlet.

Specified by:

initTemplateDataImpl in class BaseServlet

Parameters:

baseCtx - (Context) The current servlet context.

vc - (VelocityContext) The current set of Velocity template data.

cookies - (boolean) true if any relevant cookies are to be written, otherwise false.

requiresLogon

protected boolean requiresLogon(BaseServlet.Context baseCtx)

Answers if the servlet requires a valid non-default user in order to continue processing. Subclasses should override this method to answer if the subclass requires logon. Overrides requiresLogon in BaseServlet.

Specified by:

requiresLogon in class BaseServlet

Parameters:

baseCtx - (Context) The current servlet context.

Returns:

boolean - true if the servlet requires a non-default user, otherwise false.

useExistingSessionImpl

protected void useExistingSessionImpl(BaseServlet.Context baseCtx)

Provides additional application-specific functionality for using an existing session. Invoked by the useExistingSession method. Overrides useExistingSessionImpl in BaseServlet.

Specified by:

useExistingSessionImpl in class BaseServlet

Parameters:

baseCtx - (Context) The current servlet context.

writePageImpl

protected void writePageImpl(BaseServlet.Context baseCtx)

Provides additional application-specific functionality for writing a page. Invoked by the writePage method. Overrides writePageImpl in BaseServlet.

Specified by:

writePageImpl in class BaseServlet

Parameters:

baseCtx - (Context) The current servlet context.

editFormFields

protected boolean editFormFields(BaseServlet.Context baseCtx)

Edits the values from the html template's form fields. Invoked by the doPost method. Overrides editFormFields in BaseServlet.

Specified by:

editFormFields in class BaseServlet

Parameters:

baseCtx - (Context) The current servlet context.

Returns:

boolean - true if all the edits are successful, otherwise false.

getNextURL

protected java.lang.String getNextURL(BaseServlet.Context baseCtx)

Returns the next URL (including parameters) to be processed when this servlet's processing has been successfully completed (no edit errors, etc.). Invoked by the writeURL method. Overrides getNextURL in BaseServlet.

Specified by:

getNextURL in class BaseServlet

Parameters:

baseCtx - (Context) The current servlet context.

Returns:

String - The URL.

getTemplateName

protected java.lang.String getTemplateName(BaseServlet.Context baseCtx)

Returns the name of the html template file used by the servlet. Invoked by the writePage method. Overrides getTemplateName in BaseServlet.

Specified by:

getTemplateName in class BaseServlet

Parameters:

baseCtx - (Context) The current servlet context.

Returns:

String - The html template's name.

readParameters

protected void readParameters(BaseServlet.Context baseCtx,
                              boolean post)

Reads the parameters passed to the servlet via the http request object. Invoked by the doGet and doPost method. Overrides readParameters in BaseServlet.

Specified by:

readParameters in class BaseServlet

Parameters:

baseCtx - (Context) The current servlet context.

post - (boolean) true if the method is invoked from doPost, otherwise false.

resetFormFields

protected void resetFormFields(BaseServlet.Context baseCtx)

Resets the values for the html template's form fields. Invoked by the doGet and doPost methods. Overrides resetFormFields in BaseServlet.

Specified by:

resetFormFields in class BaseServlet

Parameters:

baseCtx - (Context) The current servlet context.

setCookieValues

protected void setCookieValues(BaseServlet.Context baseCtx)
                        throws java.io.IOException

Adds one or more values to the http session cookies. Invoked by the writeURL method. Calls should be made to writeCookie for each cookie that needs to be set. Overrides setCookieValues in BaseServlet.

Specified by:

setCookieValues in class BaseServlet

Parameters:

baseCtx - (Context) The current servlet context.

Throws:

java.io.IOException - - if an error occurs when adding the cookie to the response header.

setSessionValues

protected void setSessionValues(BaseServlet.Context baseCtx)

Adds one or more values to the http session object. Invoked by the writeURL method. Overrides setSessionValues in BaseServlet.

Specified by:

setSessionValues in class BaseServlet

Parameters:

baseCtx - (Context) The current servlet context.

setTemplateData

protected void setTemplateData(BaseServlet.Context baseCtx)

Sets the various data required by the html template. Invoked by the writePage method. Overrides setTemplateData in BaseServlet.

Specified by:

setTemplateData in class BaseServlet

Parameters:

baseCtx - (Context) The current servlet context.

removeFromStack

protected void removeFromStack(BaseServlet.Context ctx)
                        throws java.io.IOException

Redirects to the appropriate servlet in the history stack and then removes the servlet from the stack.

Parameters:

ctx - (Context) The current servlet context.

Throws:

java.io.IOException - - if an error occurs while processing the URL redirection.