com.nwoods.jgo.web
Class JGoImageServlet

java.lang.Object
  javax.servlet.GenericServlet
      javax.servlet.http.HttpServlet
          com.nwoods.jgo.web.JGoImageServlet

All Implemented Interfaces:

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

public class JGoImageServlet

extends javax.servlet.http.HttpServlet

This class implements an HttpServlet that produces JPEG images of JGoDocuments rather than HTML pages.

The servlet keeps an arbitrary number of named documents (JGoDocument) indexed in the ServletContext. The HttpSession keeps the current view (JGoJPEGView), so that the current selection and view size/position/scale are maintained and accessible from other servlets.

This servlet can handle additional requests besides just generating an image to be displayed by the browser. It can handle arbitrary actions as specified in the "act" parameter. It also handles keyboard commands and mouse commands. The exact behaviors can be customized by the cooperation of the HTML page invoking this servlet and the implementation of this servlet.

See Also:

Serialized Form

Constructor Summary

JGoImageServlet()

Method Summary

void	adjustScale(JGoJPEGView view, java.lang.String scalestr) Scale requests are a little more complex than just specifying the new scale as a double float.
void	doGet(javax.servlet.http.HttpServletRequest request, javax.servlet.http.HttpServletResponse response) This method processes the mouse down and up events on the JGoJPEGView named in the GoView parameter by using JGoImageEventProcessor, and then produces a JPEG image of that view.
void	doPost(javax.servlet.http.HttpServletRequest request, javax.servlet.http.HttpServletResponse response)
static java.lang.String	getRequestParameter(javax.servlet.http.HttpServletRequest request, java.lang.String p, java.lang.String def) convenience function for defaulting parameters
static boolean	getRequestParameterBoolean(javax.servlet.http.HttpServletRequest request, java.lang.String p, boolean def) convenience function for defaulting parameters
static double	getRequestParameterDouble(javax.servlet.http.HttpServletRequest request, java.lang.String p, double def) convenience function for defaulting parameters
static int	getRequestParameterInt(javax.servlet.http.HttpServletRequest request, java.lang.String p, int def) convenience function for defaulting parameters
void	init()
void	produceImage(javax.servlet.http.HttpServletRequest request, javax.servlet.http.HttpServletResponse response, JGoJPEGView view) Generate the image, using docx, docy as the upper left corner, a size of width, height, and a scale factor of scale.

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, log, log

Methods inherited from class java.lang.Object

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

Constructor Detail

JGoImageServlet

public JGoImageServlet()

Method Detail

doPost

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

Throws:

javax.servlet.ServletException

java.io.IOException

doGet

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

This method processes the mouse down and up events on the JGoJPEGView named in the GoView parameter by using JGoImageEventProcessor, and then produces a JPEG image of that view. If the GoViewData parameter is not blank, it will generate the JavaScript data associated with the view. The JavaScript data includes tooltip and cursor data.

Throws:

javax.servlet.ServletException

java.io.IOException

produceImage

public void produceImage(javax.servlet.http.HttpServletRequest request,
                         javax.servlet.http.HttpServletResponse response,
                         JGoJPEGView view)

Generate the image, using docx, docy as the upper left corner, a size of width, height, and a scale factor of scale. All of the parameters as passed in as part of the request HttpServletRequest. Generate the image, using the view's defaults if not specified in request.

Parameters:

request -

response -

view -

adjustScale

public void adjustScale(JGoJPEGView view,
                        java.lang.String scalestr)

Scale requests are a little more complex than just specifying the new scale as a double float. They can be prefixed with "*", "+", and "-", to indicate that the current scale should be adjusted in that manner by the following double value.

Parameters:

view -

scalestr -

init

public void init()
          throws javax.servlet.ServletException

Throws:

javax.servlet.ServletException

getRequestParameter

public static java.lang.String getRequestParameter(javax.servlet.http.HttpServletRequest request,
                                                   java.lang.String p,
                                                   java.lang.String def)

convenience function for defaulting parameters

Parameters:

request -

p - parameter whose value is requested

def - default value

Returns:

getRequestParameterInt

public static int getRequestParameterInt(javax.servlet.http.HttpServletRequest request,
                                         java.lang.String p,
                                         int def)

convenience function for defaulting parameters

Parameters:

request -

p - parameter whose value is requested

def - default value

Returns:

getRequestParameterDouble

public static double getRequestParameterDouble(javax.servlet.http.HttpServletRequest request,
                                               java.lang.String p,
                                               double def)

convenience function for defaulting parameters

Parameters:

request -

p -

def -

Returns:

getRequestParameterBoolean

public static boolean getRequestParameterBoolean(javax.servlet.http.HttpServletRequest request,
                                                 java.lang.String p,
                                                 boolean def)

convenience function for defaulting parameters

Parameters:

request -

p -

def -

Returns: