linkguilist.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.

// **********************************************************************
// 
// <copyright>
// 
//  BBN Technologies
//  10 Moulton Street
//  Cambridge, MA 02138
//  [phone]
// 
//  Copyright (C) BBNT Solutions LLC. All rights reserved.
// 
// </copyright>
// **********************************************************************
// 
// $Source: /cvs/distapps/openmap/src/openmap/com/bbn/openmap/layer/link/LinkGUIList.java,v $
// $RCSfile: LinkGUIList.java,v $
// $Revision: 1.2.2.2 $
// $Date: 2005/08/09 18:10:44 $
// $Author: dietrick $
// 
// **********************************************************************

package com.bbn.openmap.layer.link;

import java.io.EOFException;
import java.io.IOException;

import javax.swing.JComponent;

import com.bbn.openmap.util.Debug;

/**
 */
public class LinkGUIList {

    /** Link used for the transmission/reception of widgets. */
    Link link = null;
    /** GUI widget list received. */
    JComponent widgets = null;
    /** The terminator of the graphics section when receiving graphics. */
    String linkStatus = Link.END_TOTAL;
    /** Version Number of request format. */
    protected static float version = Link.LINK_VERSION;

    /** Write a gui section to the link. */
    public LinkGUIList(Link link) throws IOException {
        this.link = link;
        link.start(Link.GUI_HEADER);
        link.dos.writeFloat(version);
    }

    /**
     */
    public JComponent getGUI() {
        return widgets;
    }

    /**
     * After reading the graphics response, this returns the section
     * ending string terminating the graphics section, either
     * Link.END_TOTAL or Link.END_SECTION.
     * 
     * @return either Link.END_TOTAL or Link.END_SECTION.
     */
    public String getLinkStatus() {
        return linkStatus;
    }

    /**
     * The server method that needs to be called at the end of sending
     * a gui response. This will tell the link what type of teminator
     * to put on the end of the graphics response section, and also
     * tell the link to fluxh the output stream..
     * 
     * @param endType use Link.END_SECTION if you want to add more
     *        types of response sections. Use Link.END_TOTAL at the
     *        end of the total transmission.
     * @throws IOException
     */
    public void end(String endType) throws IOException {
        link.end(endType);
    }

    /**
     * @throws IOException
     * @throws EOFException
     */
    protected String readWidgets() throws IOException, EOFException {

        long startTime = System.currentTimeMillis();
        String header = null;
        int widgetType;

        float ver = link.dis.readFloat();
        Debug.message("link", "LinkGUIList: reading graphics: version(" + ver + ")");

        while (true) {

            // Just consume the header, don't create a useless
            // string object.
            header = link.readDelimiter(false);

            if (header == Link.END_TOTAL || header == Link.END_SECTION) {

                long endTime = System.currentTimeMillis();
                Debug.message("link", "LinkGUIList: received bytes in "
                        + (float) (endTime - startTime) / 1000.0f + " seconds");

                return header;
            }

            widgetType = link.dis.readInt();

            switch (widgetType) {

            default:
                System.err.println("LinkGUIList: received unknown graphic type.");
            }
        }
    }
}