Class sun.server.http.ImagemapServlet

All Packages  Class Hierarchy  This Package  Previous  Next  Index

Class sun.server.http.ImagemapServlet

java.lang.Object
   |
   +----java.servlet.GenericServlet
           |
           +----java.servlet.http.HttpServlet
                   |
                   +----sun.server.http.ImagemapServlet

public class ImagemapServlet
extends HttpServlet

Servlet for handling server-side imagemap requests

ImagemapServlet(): Creates a new imagemap servlet.

distanceSquared(Point, Point): Calculates the square of the Euclidian distance between two points
getServletInfo(): Returns information about the servlet
main(String[])
parseMapFile(HttpServletRequest, HttpServletResponse, Point, File): This function parses the requested mapfile a determines the URL associated with the clicked point.
parseMenuText(StreamTokenizer, URL, String, String): Reads in the optional text that is display on text only browsers
parsePoint(StreamTokenizer): Parses and returns a point from the input stream.
pointInCircle(Point, Point, Point): Checks if the given point is within the bounds of the specified circle
pointInPoly(Point, Vector): Checks if the given point is within the bounds of the specified polygon
pointInRect(Point, Point, Point): Checks if the given point is within the bounds of the specified rectangle
sendErrorResponse(HttpServletResponse, String): Returns an error message to the user if some error occured while processing the imagemap request
sendMenuResponse(HttpServletResponse, String): Responds with a textual menu of all available links in the mapfile
sendResponse(HttpServletResponse, URL): Returns a redirect response with the proper URL, or a "no content" response if no matching URL could be found
service(HttpServletRequest, HttpServletResponse): Services a single imagemap request from the client.

ImagemapServlet

  public ImagemapServlet()

Creates a new imagemap servlet.

service

  public void service(HttpServletRequest req,
                      HttpServletResponse res) throws ServletException, IOException

Services a single imagemap request from the client.

Parameters:: req - the HTTP request; res - the HTTP response
Throws: IOException: If an I/O error has occurred.
Overrides:: service in class HttpServlet

parseMapFile

  public void parseMapFile(HttpServletRequest req,
                           HttpServletResponse res,
                           Point clickPoint,
                           File mapFile) throws IOException

This function parses the requested mapfile a determines the URL associated with the clicked point.

The imagemap servlet recognizes standard NCSA mapfiles. In addition it recognizes the following enhancements:

Lines of type rect, circle, point, poly, and default may have an optional quoted string at the end of the line which is desplayed in the menu generated for text only browsers.
A line of type text consisting of the text keyword and a quoted string will cause the quoted text (which may contain HTML markup) to appear in the menu generated for text only browsers in the order it appears in the mapfile.
A line of type base can be used to specify a different base URL for any relative URLs that appear in the mapfile after the base line. The options are:

base map
The URL of the mapfile is used as the base URL.
base referer
The URL of the document containing the imagemap is used as the base URL.
base URL
The full URL given is used as the base URL.

Each line may be one of the following types: (the quoted descriptions are optional)

rect    URL left,top right,bottom "description"
circle  URL centerX,centerY edgePtX,edgePtY "description" 
poly    URL pt1X,pt1Y pt2X,pt2Y ... ptnX,ptnY "description"
default URL "description"
point   URL ptX,ptY "description"
text  "arbitrary marked-up text" 
base  map | referer | URL
#comment lines must begin with a #

Parameters:: req - the HTTP request; res - the HTTP response; clickPoint - the point the user clicked; mapFile - the mapFile that maps points to URLs

parsePoint

  protected static Point parsePoint(StreamTokenizer tokenStream) throws IOException, InvalidFileFormatException

Parses and returns a point from the input stream. The point must be in the form int,int

Parameters:: tokenStream - the stream to parse
Returns:: a point derieved from the next 3 token on the input stream
Throws: IOException: If an I/O error has occurred.

parseMenuText

  protected static String parseMenuText(StreamTokenizer tokenStream,
                                        URL url,
                                        String type,
                                        String menuText) throws IOException

Reads in the optional text that is display on text only browsers

Parameters:: tokenStream - the current StreamTokenizer; url - the url to insert in the menu; type - the type of mapfile entry, which will be desplayed by default if no optional text is provided; menuText - the menu text built up so far
Returns:: the menu text built up so far

pointInRect

  protected static boolean pointInRect(Point clickPoint,
                                       Point upperLeft,
                                       Point lowerRight)

Checks if the given point is within the bounds of the specified rectangle

Parameters:: clickPoint - the point clicked by the user; upperLeft - the upper left corner of the rectangle; lowerRight - the lower right corner of the rectangle

pointInCircle

  protected static boolean pointInCircle(Point clickPoint,
                                         Point center,
                                         Point edge)

Checks if the given point is within the bounds of the specified circle

Parameters:: clickPoint - the point clicked by the user; center - the center point of the circle; edge - any point on the edge of the circle

distanceSquared

  protected static int distanceSquared(Point point1,
                                       Point point2)

Calculates the square of the Euclidian distance between two points

Parameters:: point1 - the first point; point2 - the second point

pointInPoly

  protected static boolean pointInPoly(Point clickPoint,
                                       Vector points)

Checks if the given point is within the bounds of the specified polygon

Parameters:: clickPoint - the point clicked by the user; points - a vector of points describing the polygon

sendMenuResponse

  protected void sendMenuResponse(HttpServletResponse res,
                                  String menu) throws IOException

Responds with a textual menu of all available links in the mapfile

Parameters:: req - the HTTP response; menu - the text menu to display
Throws: IOException: If an I/O error has occurred.

sendErrorResponse

  protected void sendErrorResponse(HttpServletResponse res,
                                   String error) throws IOException

Returns an error message to the user if some error occured while processing the imagemap request

Parameters:: req - the HTTP response; error - a description of the error
Throws: IOException: If an I/O error has occurred.

sendResponse

  protected void sendResponse(HttpServletResponse res,
                              URL redirectURL) throws IOException

Returns a redirect response with the proper URL, or a "no content" response if no matching URL could be found

Parameters:: req - the HTTP response; redirectURL - the URL to redirect to
Throws: IOException: If an I/O error has occurred.

getServletInfo

  public String getServletInfo()

Returns information about the servlet

Overrides:: getServletInfo in class GenericServlet

main

  public static void main(String args[])

All Packages  Class Hierarchy  This Package  Previous  Next  Index