maprequesthandler.java

openmap java写的开源数字地图程序. 用applet实现,可以像google map 那样放大缩小地图.

     */
    public byte[] handleRequest(String request) throws IOException,
            MapRequestFormatException {

        Properties requestProperties = convertRequestToProps(request);
        String requestType = requestProperties.getProperty(REQUEST);

        if (requestType != null) {
            if (requestType.equalsIgnoreCase(MAP)) {
                Debug.message("imageserver", "MRH: Map request...");
                return handleMapRequest(requestProperties);
                //          } else if
                // (requestType.equalsIgnoreCase(CAPABILITIES)) {
                //              Debug.message("imageserver", "MRH: Capabilities
                // request...");
                //              handleCapabilitiesRequest(requestProperties, out);
            } else {
                throw new MapRequestFormatException("Request type not handled: "
                        + requestType);
            }
        } else {
            throw new MapRequestFormatException("Request not understood: "
                    + request);
        }
    }

    /**
     * Given a general request, parse it and handle it. Appends a
     * content type to the output stream which may mess things up for
     * servlets asking for images.
     * 
     * @param request the request string of key value pairs.
     * @param out OutputStream to reply on.
     */
    public void handleRequest(String request, OutputStream out)
            throws IOException, MapRequestFormatException {

        Properties requestProperties = convertRequestToProps(request);

        String requestType = requestProperties.getProperty(REQUEST);
        if (requestType != null) {
            if (requestType.equalsIgnoreCase(MAP)) {
                Debug.message("imageserver", "MRH: Map request...");
                handleMapRequest(requestProperties, out);
            } else if (requestType.equalsIgnoreCase(CAPABILITIES)) {
                Debug.message("imageserver", "MRH: Capabilities request...");
                handleCapabilitiesRequest(requestProperties, out);
            } else if (requestType.equalsIgnoreCase(PAN)) {
                Debug.message("imageserver", "MRH: Pan request...");
                handlePanRequest(requestProperties, out);
            } else if (requestType.equalsIgnoreCase(RECENTER)) {
                Debug.message("imageserver", "MRH: Recenter request...");
                handleRecenterRequest(requestProperties, out);

            } else {
                throw new MapRequestFormatException("Request type not handled: "
                        + requestType);
            }
        } else {
            throw new MapRequestFormatException("Request not understood: "
                    + request);
        }

    }

    /**
     * Handle a map request, and create and image for it.
     * 
     * @param requestProperties the request in properties format.
     * @return byte[] of formatted image.
     */
    public byte[] handleMapRequest(Properties requestProperties)
            throws IOException, MapRequestFormatException {

        Proj projection = ImageServerUtils.createOMProjection(requestProperties,
                defaultProjection);

        setBackground(ImageServerUtils.getBackground(requestProperties));

        boolean formatFound = false;

        String format = requestProperties.getProperty(FORMAT);
        if (format != null) {
            formatFound = setFormatter(format.toUpperCase());
            formatFound = true;
            Debug.message("imageserver", "Format requested " + format);
        }

        if (Debug.debugging("imageserver")
                && (format == null || formatFound == false)) {
            Debug.output("MRH: no formatter defined, using default");
        }

        byte[] image;

        // We need to think about using the layer mask, parsing it
        // intelligently, and not using it if it's a little freaky.

        //      String strLayerMask =
        // requestProperties.getProperty(LAYERMASK);
        //      // default is to show all the layers server knows about.
        //      int layerMask = 0xFFFFFFFF;
        //      if (strLayerMask != null) {
        //          if (Debug.debugging("imageserver") {
        //              Debug.output("MRH.handleMapRequest: LayerMask unsigned int
        // is " +
        //                           strLayerMask);
        //          }
        //          layerMask = Integer.parseInt(strLayerMask);
        //      }

        String strLayers = requestProperties.getProperty(LAYERS);

        // Pass any properties to the layers??? Maybe if another
        // property is set, to bother with taking up the time to run
        // through all of this...

        if (strLayers != null) {

            Vector layers = PropUtils.parseMarkers(strLayers, ",");
            if (Debug.debugging("imageserver")) {
                Debug.output("MRH.handleMapRequest: requested layers >> "
                        + layers);
            }
            image = createImage(projection, -1, -1, layers);
        } else {
            // if LAYERS property is not specified
            // Check default layers or if visibility should be used to
            // determine default

            if (getUseVisibility()) {
                if (Debug.debugging("imageserver")) {
                    Debug.output("MRH.handleMapRequest: Using visibility to determine layers");
                }
                image = createImage(projection,
                        -1,
                        -1,
                        calculateVisibleLayerMask());
            } else {
                Vector layers = PropUtils.parseMarkers(defaultLayers, " ");
                if (Debug.debugging("imageserver")) {
                    Debug.output("MRH.handleMapRequest: requested layers >> "
                            + layers + " out of " + getAllLayerNames());
                }
                image = createImage(projection, -1, -1, layers);
            }
        }
        return image;
    }

    /**
     * Handle a Map Request. Appends a content type to the output
     * stream which may mess things up for servlets.
     */
    public void handleMapRequest(Properties requestProperties, OutputStream out)
            throws IOException, MapRequestFormatException {

        byte[] image = handleMapRequest(requestProperties);

        if (Debug.debugging("imageserver")) {
            Debug.output("MRH: have completed image, size " + image.length);
        }

        String contentType = getFormatterContentType(getFormatter());

        if (contentType == null) {
            contentType = HttpConnection.CONTENT_PLAIN;
        }

        Debug.message("imageserver", "MRH: have type = " + contentType);

        HttpConnection.writeHttpResponse(out, contentType, image);
    }

    /**
     * Handle a Pan Request.
     */
    public void handlePanRequest(Properties requestProperties, OutputStream out)
            throws IOException, MapRequestFormatException {

        Proj projection = ImageServerUtils.createOMProjection(requestProperties,
                defaultProjection);

        String contentType = HttpConnection.CONTENT_PLAIN;
        String response;
        float panAzmth;

        try {
            panAzmth = Float.parseFloat(requestProperties.getProperty(AZIMUTH));
            projection.pan(panAzmth);
        } catch (Exception exc) {
            Debug.output("MSH: Invalid Azimuth");
        }

        response = Math.round(projection.getCenter().getLatitude() * 100.0)
                / 100.0 + ":"
                + Math.round(projection.getCenter().getLongitude() * 100.0)
                / 100.0;

        HttpConnection.writeHttpResponse(out, contentType, response);
    }

    /**
     * Handle a Recenter Request. Appends a content type to the output
     * stream which may mess things up for servlets.
     */
    public void handleRecenterRequest(Properties requestProperties,
                                      OutputStream out) throws IOException,
            MapRequestFormatException {

        Proj projection = ImageServerUtils.createOMProjection(requestProperties,
                defaultProjection);

        String contentType = HttpConnection.CONTENT_PLAIN;
        ;
        String response;

        try {
            int x = Integer.parseInt(requestProperties.getProperty(X));
            int y = Integer.parseInt(requestProperties.getProperty(Y));
            projection.setCenter(projection.inverse(x, y));
        } catch (Exception exc) {
            Debug.output("MSH: Invalid Azimuth");
        }

        response = Math.round(projection.getCenter().getLatitude() * 100.0)
                / 100.0 + ":"
                + Math.round(projection.getCenter().getLongitude() * 100.0)
                / 100.0;

        HttpConnection.writeHttpResponse(out, contentType, response);
    }

    /**
     * Given an ImageFormatter, get the HttpConnection content type
     * that matches it.
     */
    public String getFormatterContentType(ImageFormatter formatter) {
        String ret = null;
        String label = formatter.getFormatLabel();

        String[] knownContentTypes = HttpConnection.getAllContentTypes();

        for (int i = 0; i < knownContentTypes.length; i++) {
            if (knownContentTypes[i].indexOf(label.toLowerCase()) != -1) {
                ret = knownContentTypes[i];
                break;
            }
        }
        return ret;
    }

    /**
     * Handle a capabilities request.
     */
    public void handleCapabilitiesRequest(Properties requestProperties,
                                          OutputStream out) throws IOException,
            MapRequestFormatException {

        if (Debug.debugging("imageserver")) {
            Debug.output("MRH.handleCapabilitiesRequest: unimplemented");
        }

        throw new MapRequestFormatException("Capabilities request currently not handled");
    }
}