link.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.

            if (delimiter == GRAPHICS_HEADER) {
                if (layer != null) {
                    graphicList = new LinkGraphicList(this, graphics, layer.getProjection(), generator);
                } else {
                    graphicList = new LinkGraphicList(this, graphics, proj, generator);
                }
                delimiter = graphicList.getLinkStatus();
            } else if (delimiter == ACTIONS_HEADER) {
                actionList = new LinkActionList(this, layer, proj, generator);
                delimiter = actionList.getLinkStatus();
            } else if (delimiter == GUI_HEADER) {
                guiList = new LinkGUIList(this);
                delimiter = guiList.getLinkStatus();
            } else if (delimiter == CLOSE_LINK_HEADER) {
                closeLink = true;
            } else if (delimiter == SHUTDOWN_HEADER) {
                Debug.message("link", "Link.received command to exit");
                if (obeyCommandToExit) {
                    System.exit(0);
                }
            } else if (delimiter == HUH_HEADER) {
                delimiter = readDelimiter(true);
            } else if (delimiter == MAP_REQUEST_HEADER) {
                mapRequest = new LinkMapRequest(this);
                delimiter = mapRequest.getLinkStatus();
            } else if (delimiter == ACTION_REQUEST_HEADER) {
                actionRequest = new LinkActionRequest(this);
                delimiter = actionRequest.getLinkStatus();
            } else if (delimiter == GUI_REQUEST_HEADER) {
                guiRequest = new LinkGUIRequest(this);
                delimiter = guiRequest.getLinkStatus();
            } else if (delimiter == PING_REQUEST_HEADER) {
                start(PING_RESPONSE_HEADER);
                end(END_TOTAL);
                delimiter = readDelimiter(false);
            }

            if (delimiter == END_TOTAL) {
                return;
            }
        }
    }

    public void setObeyCommandToExit(boolean value) {
        obeyCommandToExit = value;
    }

    public boolean getAcceptCommandToExit() {
        return obeyCommandToExit;
    }

    /**
     * After a readAndParse() has been called on a link, this can be
     * called to retrieve a graphics request, if one was sent.
     * 
     * @return LinkMapRequest containing the request.
     */
    public LinkMapRequest getMapRequest() {
        return mapRequest;
    }

    /**
     * After a readAndParse() has been called on a link, this can be
     * called to retrieve graphics in an LinkOMGraphicList, if any
     * graphics were sent.
     * 
     * @return GraphicLinkRsponse containing the information. If no
     *         graphics were sent the list will be empty.
     */
    public LinkGraphicList getGraphicList() {
        return graphicList;
    }

    /**
     * After a readAndParse() has been called on a link, this can be
     * called to retrieve a gesture notification/request, if one was
     * sent.
     * 
     * @return LinkActionRequest containing the request.
     */
    public LinkActionRequest getActionRequest() {
        return actionRequest;
    }

    /**
     * After a readAndParse() has been called on a link, this can be
     * called to retrieve the gesture response.
     * 
     * @return LinkActionList containing the information.
     */
    public LinkActionList getActionList() {
        return actionList;
    }

    /**
     * After a readAndParse() has been called on a link, this can be
     * called to retrieve a gesture notification/request, if one was
     * sent.
     * 
     * @return LinkGUIRequest containing the request.
     */
    public LinkGUIRequest getGUIRequest() {
        return guiRequest;
    }

    /**
     * After a readAndParse() has been called on a link, this can be
     * called to retrieve the GUI response, if any GUI components were
     * sent.
     *  
     */
    public LinkGUIList getGUIList() {
        return guiList;
    }

    /**
     * readDelimiter is a function designed to read a header string
     * off the data input stream in the Link object. It expects that
     * the next byte off the link will be a ' <' in the stream, and
     * then reads through the stream until it finds the '>' expected
     * at the end of the string. It will also return a string version
     * of END_TOTAL or END_SECTION if it is encountered instead. If
     * desired, an intern version of the string is returned.
     * 
     * @param returnString if true, an intern String version of the
     *        characters is returned.
     * @throws IOException
     * @throws ArrayIndexOutOfBoundsException
     */
    protected String readDelimiter(boolean returnString) throws IOException,
            ArrayIndexOutOfBoundsException {
        String ret = END_TOTAL;

        char END_TOTAL_CHAR = END_TOTAL.charAt(0);
        char END_SECTION_CHAR = END_SECTION.charAt(0);

        char c = (char) dis.readByte();

        // NOTE: possibility of early exits here...
        if (c == END_TOTAL_CHAR) {
            Debug.message("link", "Link|readDelimiter: Found END_TOTAL");
            return END_TOTAL;
        } else if (c == END_SECTION_CHAR) {
            Debug.message("link", "Link|readDelimiter: Found END_SECTION");
            return END_SECTION;
        } else if (c != '<') {
            if (Debug.debugging("link")) {
                System.out.println("Link|readDelimiter: unexpected protocol data read '"
                        + c + "'");
            }
            throw new IOException("readDelimiter: unexpected protocol data read.");
        }

        // The byte read does indeed equal '<'
        int charCount = 0;

        // c should == '<'
        charArray[charCount++] = c;
        // Get the rest of the header information
        c = (char) dis.readByte();
        while (c != '>' && charCount < MAX_HEADER_LENGTH - 1) {
            charArray[charCount++] = c;
            c = (char) dis.readByte();
        }

        // c should == '>' or uh-oh - too many characters between
        // them. Exit with a faulty return if this is the case.
        if (c != '>') {
            throw new IOException("readDelimiter: header is too long.");
        }

        charArray[charCount++] = c;

        // OK, got it - return string
        if (returnString) {
            ret = new String(charArray, 0, charCount).intern();
        } else {
            ret = "";
        }
        return ret;
    }

    /**
     * Other threads can check to see if the link is in use.
     * 
     * @return true if link in use and unavailable.
     */
    public boolean isLocked() {
        return locked;
    }

    /**
     * Set the lock. Should only be called in a synchronized block of
     * code, where you have control over the link.
     * 
     * @param set true if the lock should be turned on, false if the
     *        link should be released.
     */
    public synchronized boolean setLocked(boolean set) {
        if (set == true) {
            if (locked == true) {
                // The lock was NOT set for the caller - unsuccessful.
                return false;
            } else {
                locked = true;
                // The lock was set for the caller, successfully.
                return true;
            }
        } else {
            locked = set;
            // The state was set to false, successfully.
            return true;
        }
    }

    /**
     * This method is provided for those who want to optimize how they
     * write the graphical objects to the output stream. Look in the
     * Link <graphics>API to find out the order of the pieces for
     * each graphic type. Not recommended for the faint of heart.
     */
    public DataOutput getDOS() {
        return dos;
    }

    /**
     * This method complements getDOS().
     */
    public DataInput getDIS() {
        return dis;
    }

    /**
     * Returns the number of bytes written since the last
     * clearBytesWritten() call.
     */
    public int getBytesWritten() {
        return dos.size();
    }

    /**
     * Reset the bytes written count to 0.
     * 
     * @return the old byte count
     */
    public int clearBytesWritten() {
        return dos.clearWritten();
    }
}