websitehelpmenuitem.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/gui/menu/WebSiteHelpMenuItem.java,v $
// $RCSfile: WebSiteHelpMenuItem.java,v $
// $Revision: 1.2.2.1 $
// $Date: 2004/10/14 18:26:56 $
// $Author: dietrick $
// 
// **********************************************************************

package com.bbn.openmap.gui.menu;

import javax.swing.*;
import java.awt.event.*;

import com.bbn.openmap.Environment;
import com.bbn.openmap.InformationDelegator;
import com.bbn.openmap.LightMapHandlerChild;

/**
 * This object tells a browser to bring up the OpenMap Website help.
 */
public class WebSiteHelpMenuItem extends JMenuItem implements ActionListener,
        LightMapHandlerChild {

    protected InformationDelegator informationDelegator = null;

    public WebSiteHelpMenuItem() {
        super("OpenMap WebSite Help");
        setMnemonic('h');
        addActionListener(this);
        setEnabled(false); // enabled when InformationDelegator found.
    }

    /**
     * @param in_informationDelegator
     */
    public void setInformationDelegator(
                                        InformationDelegator in_informationDelegator) {
        informationDelegator = in_informationDelegator;
        setEnabled(informationDelegator != null);
    }

    /**
     * Return current value of InformationDelegator.
     */
    protected InformationDelegator getInformationDelegator() {
        return informationDelegator;
    }

    public void actionPerformed(ActionEvent ae) {
        if (informationDelegator != null) {
            informationDelegator.displayURL(Environment.get(Environment.HelpURL,
                    "http://openmap.bbn.com/doc/user-guide.html"));
        }
    }

    public void findAndInit(Object someObj) {
        if (someObj instanceof InformationDelegator) {
            setInformationDelegator((InformationDelegator) someObj);
        }
    }

    public void findAndUndo(Object someObj) {
        if (someObj instanceof InformationDelegator
                && getInformationDelegator() == (InformationDelegator) someObj) {
            setInformationDelegator(null);
        }
    }
}