creamtec.webcream
Class ServletHelper

java.lang.Object
  creamtec.webcream.ServletHelper

All Implemented Interfaces:

WebCreamServlet

public class ServletHelper
extends java.lang.Object
implements WebCreamServlet

Provides implementation for most of the logic of processing an incoming HTTP servlet request and forwarding it to a client agent.

Nested Class Summary

class	ServletHelper.InProcessAppDesc Declare this class to resolve classpath to the application classes.
static class	ServletHelper.InProcessClientAgent Declare this class to resolve classpath to the application classes.

Field Summary

static java.lang.String	APP_NAME
FileUploadHandler	fileUploadHandler
static java.lang.String	PROPS_FILE_NAME

Method Summary

ClientAgent	createClientAgent(java.lang.String appName) Creates a new client agent.
java.lang.String	decodeValue(java.lang.String value) Decode value from the source encoding into internal UTF8 encoding
AppDesc	getAppDesc(javax.servlet.http.HttpServletRequest request, HttpRequestData data) Returns the application descriptor for a given request
ClientAgentRemote	getClientAgent(AppDesc appDesc, javax.servlet.http.HttpServletRequest request, HttpRequestData data, javax.servlet.http.HttpServletResponse response) Returns a client agent that should process the given request.
static int	getClientId(ClientAgentRemote agent) We have to use Object's implementation of hashCode() because RemoteObject always return the same value for all out-of-process agents
java.lang.String	getDocsRealPath(AppDesc appDesc, javax.servlet.http.HttpServletRequest request) Real path is disk path such as C:\Java\WebCream and it's needed for SnapshotRenderer temp directory
java.lang.String	getErrorPage(AppDesc appDesc, java.lang.Throwable x, javax.servlet.http.HttpServletRequest request) Renders a simple error page used for system errors.
static ServletHelper	getInstance(javax.servlet.ServletContext servletContext, java.lang.String sourceEncoding) Returns the instance of the servlet helper
static java.lang.String	getListenerName(java.lang.String appName) Helper method to return the listener name for a given application name
java.lang.String	getParameterValue(javax.servlet.http.HttpServletRequest request, java.lang.String name) Returns the value of the given request parameter
java.lang.String[]	getParameterValues(javax.servlet.http.HttpServletRequest request, java.lang.String name) Returns all values of a HTTP request parameter.
RouterRequestFilter	getRequestFilter() Returns the request filter instance
java.lang.String	getServerURL(AppDesc appDesc, javax.servlet.http.HttpServletRequest request) Obtains the web server URL based on the scheme, port and web app context.
java.lang.Object	getSessionAttribute(javax.servlet.http.HttpSession session, java.lang.String name) Version-safe way of getting a value from a session
java.lang.String	getSubmitURL(AppDesc appDesc, javax.servlet.http.HttpServletRequest request) Obtains the submit URL based on the application configuration or the request URL
void	parseAppNameAndAction(javax.servlet.http.HttpServletRequest request, HttpRequestData data) Obtain application name and the requested action from HTTP parameters and query string
void	processHttpRequest(javax.servlet.http.HttpServletRequest request, javax.servlet.http.HttpServletResponse response) Extracts parameters from HttpServletRequest, finds (creates) a client agent and delegates to it for processing and HTML generation.
void	processRequestData(AppDesc appDesc, javax.servlet.http.HttpServletRequest request, HttpRequestData data) Extracts and processes the request data
boolean	processRouterMode(javax.servlet.http.HttpServletRequest request, HttpRequestData data) Sets the servlet parameters such as the application name and action based on the deployment method
void	removeSessionAttribute(javax.servlet.http.HttpSession session, java.lang.String name) Version-safe way of removing a value from a session
void	setDataFromPath(HttpRequestData data, java.lang.String path) Extracts the servlet parameters such as the application name and action from the given string
void	setSessionAttribute(javax.servlet.http.HttpSession session, java.lang.String name, java.lang.Object value) Version-safe way of storing a value in a session
void	shutdown() Shuts down agents and all running external JVMs
static void	shutdownAgent(AppDesc appDesc, java.lang.Integer sessionId, ClientAgentRemote agent) Shuts down the client agent

Methods inherited from class java.lang.Object

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

Field Detail

fileUploadHandler

public FileUploadHandler fileUploadHandler

APP_NAME

public static final java.lang.String APP_NAME

See Also:

Constant Field Values

PROPS_FILE_NAME

public static final java.lang.String PROPS_FILE_NAME

See Also:

Constant Field Values

Method Detail

getParameterValue

public java.lang.String getParameterValue(javax.servlet.http.HttpServletRequest request,
                                          java.lang.String name)
                                   throws java.lang.Exception

Returns the value of the given request parameter

Parameters:

request - HttpServletRequest

name - parameter name

Returns:

parameter value

Throws:

java.lang.Exception

getParameterValues

public java.lang.String[] getParameterValues(javax.servlet.http.HttpServletRequest request,
                                             java.lang.String name)
                                      throws java.lang.Exception

Returns all values of a HTTP request parameter. For instance, lists with multiple selection return all selected items.

Parameters:

request - HttpServletRequest

name - parameter name

Returns:

array of values

Throws:

java.lang.Exception

decodeValue

public java.lang.String decodeValue(java.lang.String value)
                             throws java.lang.Exception

Decode value from the source encoding into internal UTF8 encoding

Parameters:

value - String

Returns:

String

Throws:

java.lang.Exception

shutdown

public void shutdown()

Shuts down agents and all running external JVMs

processHttpRequest

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

Extracts parameters from HttpServletRequest, finds (creates) a client agent and delegates to it for processing and HTML generation.

Parameters:

request - HttpServletRequest

response - HttpServletResponse

Throws:

javax.servlet.ServletException

java.io.IOException

getErrorPage

public java.lang.String getErrorPage(AppDesc appDesc,
                                     java.lang.Throwable x,
                                     javax.servlet.http.HttpServletRequest request)

Renders a simple error page used for system errors. Can't use StandardPageRenderer because we don't have a client agent yet

getSubmitURL

public java.lang.String getSubmitURL(AppDesc appDesc,
                                     javax.servlet.http.HttpServletRequest request)
                              throws java.lang.Exception

Obtains the submit URL based on the application configuration or the request URL

Parameters:

appDesc - application descriptor

request - HttpServletRequest

Returns:

URL used to submit pages to WebCreamRouter servlet

Throws:

java.lang.Exception

getDocsRealPath

public java.lang.String getDocsRealPath(AppDesc appDesc,
                                        javax.servlet.http.HttpServletRequest request)
                                 throws java.lang.Exception

Real path is disk path such as C:\Java\WebCream and it's needed for SnapshotRenderer temp directory

Throws:

java.lang.Exception

getServerURL

public java.lang.String getServerURL(AppDesc appDesc,
                                     javax.servlet.http.HttpServletRequest request)
                              throws java.lang.Exception

Obtains the web server URL based on the scheme, port and web app context.

Parameters:

appDesc - AppDesc

request - HttpServletRequest

Returns:

String

Throws:

java.lang.Exception

processRequestData

public void processRequestData(AppDesc appDesc,
                               javax.servlet.http.HttpServletRequest request,
                               HttpRequestData data)
                        throws java.lang.Exception

Extracts and processes the request data

Parameters:

appDesc - application descriptor

request - HttpServletRequest

data - HttpRequestData

Throws:

java.lang.Exception

getClientAgent

public ClientAgentRemote getClientAgent(AppDesc appDesc,
                                        javax.servlet.http.HttpServletRequest request,
                                        HttpRequestData data,
                                        javax.servlet.http.HttpServletResponse response)
                                 throws java.lang.Exception

Returns a client agent that should process the given request. The agent is first looked up based on the session information. If an existing agent is not found, a new one is created and initialized.

Parameters:

appDesc - application descriptor

request - HttpServletRequest

data - HttpRequestData

response - HttpServletResponse

Returns:

ClientAgentRemote

Throws:

java.lang.Exception

createClientAgent

public ClientAgent createClientAgent(java.lang.String appName)
                              throws java.lang.Exception

Creates a new client agent.

Specified by:

createClientAgent in interface WebCreamServlet

Parameters:

appName - application name

Returns:

ClientAgent

Throws:

java.lang.Exception

shutdownAgent

public static void shutdownAgent(AppDesc appDesc,
                                 java.lang.Integer sessionId,
                                 ClientAgentRemote agent)

Shuts down the client agent

Parameters:

appDesc - application descriptor

sessionId - WebCream internal session identification

agent - ClientAgentRemote

getClientId

public static int getClientId(ClientAgentRemote agent)

We have to use Object's implementation of hashCode() because RemoteObject always return the same value for all out-of-process agents

Parameters:

agent -

Returns:

unique client agent id

getAppDesc

public AppDesc getAppDesc(javax.servlet.http.HttpServletRequest request,
                          HttpRequestData data)
                   throws java.lang.Exception

Returns the application descriptor for a given request

Parameters:

request - HttpServletRequest

data - HttpRequestData

Returns:

AppDesc

Throws:

java.lang.Exception

parseAppNameAndAction

public void parseAppNameAndAction(javax.servlet.http.HttpServletRequest request,
                                  HttpRequestData data)
                           throws java.lang.Exception

Obtain application name and the requested action from HTTP parameters and query string

Throws:

java.lang.Exception

processRouterMode

public boolean processRouterMode(javax.servlet.http.HttpServletRequest request,
                                 HttpRequestData data)
                          throws java.lang.Exception

Sets the servlet parameters such as the application name and action based on the deployment method

Parameters:

request - HttpServletRequest

data - HttpRequestData

Returns:

true if the method was able to determine the deployment method

Throws:

java.lang.Exception

getSessionAttribute

public java.lang.Object getSessionAttribute(javax.servlet.http.HttpSession session,
                                            java.lang.String name)
                                     throws java.lang.Exception

Version-safe way of getting a value from a session

Parameters:

session - HttpSession

name - attribute name

Returns:

value

Throws:

java.lang.Exception

setSessionAttribute

public void setSessionAttribute(javax.servlet.http.HttpSession session,
                                java.lang.String name,
                                java.lang.Object value)
                         throws java.lang.Exception

Version-safe way of storing a value in a session

Parameters:

session - HttpSession

name - attribute name

value - attribute value

Throws:

java.lang.Exception

removeSessionAttribute

public void removeSessionAttribute(javax.servlet.http.HttpSession session,
                                   java.lang.String name)
                            throws java.lang.Exception

Version-safe way of removing a value from a session

Parameters:

session - HttpSession

name - attribute name

Throws:

java.lang.Exception

setDataFromPath

public void setDataFromPath(HttpRequestData data,
                            java.lang.String path)
                     throws java.lang.Exception

Extracts the servlet parameters such as the application name and action from the given string

Parameters:

data - HttpRequestData

path - String

Throws:

java.lang.Exception

getListenerName

public static java.lang.String getListenerName(java.lang.String appName)

Helper method to return the listener name for a given application name

Parameters:

appName - String

Returns:

String

getRequestFilter

public RouterRequestFilter getRequestFilter()

Returns the request filter instance

Returns:

RouterRequestFilter or null

getInstance

public static ServletHelper getInstance(javax.servlet.ServletContext servletContext,
                                        java.lang.String sourceEncoding)
                                 throws java.lang.Exception

Returns the instance of the servlet helper

Parameters:

servletContext - ServletContext

sourceEncoding - String

Returns:

ServletHelper

Throws:

java.lang.Exception