The Net: Ultimate Internet Guide/WWLCD1.ISO/pc/java/in4wjcxu/src/como/commlet/windowcommlet.java

Java Source | 1996-08-14 | 4.7 KB | 190 lines

/*
* @(#)WindowCommlet.java    1.0 95/11/09 Ulrich Gall & Jan Kautz
*
* Copyright (c) 1996 Ulrich Gall & Jan Kautz
* [e-mail]
* Hofmannstr. 48, D-91052 Erlangen, Germany, Fax: [phone]
*
* Permission to use, copy, and distribute this software
* and its documentation for NON-COMMERCIAL purposes and without
* fee is hereby granted provided that this copyright notice
* appears in all copies. Please contact us for  further copyright
* and licensing information.
*
* WE MAKE NO REPRESENTATIONS OR WARRANTIES ABOUT THE SUITABILITY OF
* THE SOFTWARE, EITHER EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED
* TO THE IMPLIED WARRANTIES OF MERCHANTABILITY, FITNESS FOR A
* PARTICULAR PURPOSE, OR NON-INFRINGEMENT. WE SHALL NOT BE LIABLE FOR
* ANY DAMAGES SUFFERED BY LICENSEE AS A RESULT OF USING, MODIFYING OR
* DISTRIBUTING THIS SOFTWARE OR ITS DERIVATIVES.
*/
package como.commlet;

import java.awt.*;
import java.util.Date;
import como.sys.*;
import como.util.*;

/**
 * Any Commlets that might be used within other commlets should be derived
 * from WindowCommlet. This is a Frame that implements Commlet.
 *
 * Also, it can be put into a MetaCommlet.
 */
public class WindowCommlet extends Frame implements Commlet
{
    protected ComObj com;
    private MetaCommlet metacommlet = null;

    /**
    * To make it possible to set a topic, simply place this TextField anywhere in this Frame.
    * If WindowCommlet.handleEvent receives an Action from it, it sets a new topic. If a new topiv
    * is set, WindowCommlet.handleMsg() automatically updates the TextField.
    */
    private  TextField topicTF;

    public String getSessionName()
    {
        return(getCommletName() + " started on " + (new Date()).toString());
    }

    public String getCommletName()
    {
        return("Base class Windowcommlet");
    }

    public String getCommletInfo()
    {
        return("Part of the native commlets, V 1.0, Jan Kautz & Ulrich Gall");
    }

    /**
     * Returns a TextField where the user may type in the topic. If an action
     * occurs within it, the text is taken over as a new topic and sent to the other
     * commlet sessions, which then upate the contents of their topic TextField.
     */
    protected TextField getTopicTextField() {
        return topicTF;
        }

    /**
     * This also takes care of a the menu bar of its MetaCommlet, if it exists.
     * If it's not a metacommlet calls stop(). Else it only hides the frame.
     */
    public void hideCommlet()
    {
        hide();
        if (metacommlet != null)
        {
            metacommlet.setStateOfMenuItemBelongingTo(this,false);
        }
        else stop();
    }

    /**
     * Shows the commlet.
     * This also takes care of a the menu bar of its MetaCommlet, if it exists.
     */
    public void showCommlet()
    {
        show();
        if (metacommlet != null)
        {
            metacommlet.setStateOfMenuItemBelongingTo(this,true);
        }
    }

    public void setMetaCommlet(MetaCommlet m)
    {
        metacommlet = m;
    }

    public void setCom(ComObj c)
    {
        com = c;
    }

    public void init()
    {
        setTitle(getSessionName());
        topicTF = new TextField("No topic set");
    }

    /**
     * This destroys the local Commlet session. Automatically
     * called. If you ovveride this, then you have to call
     * super.stop() at the end of your method!
     */
    public void stop()
    {
        if (metacommlet == null) {
            com.logout();
        }
        dispose();
    }

    /**
     * Override this for new behaviour!
     */
    public boolean isUserAdmitted(User u)
    {
        return true;
    }

    /**
     * If a user leaves, this method will be called.
     * @param who the id of the user.
     */
    public void userLeft(int who) {}

    /**
     * If a user comes, this method will be called.
     * @param who the id of the user.
     */
    public void addUser(int who) {}

    /**
     * This is a default handleMsg() that calles the helper-methods
     * userLeft() and addUser(). And it takes care of the
     * NEW_TOPIC-message. At the moment you can be sure, that this
     * method is not called more than once at a time. But in future
     * this might change! If you need this behaviour then
     * make it synchronized!
     */
    public boolean handleMsg(Msg msg)
    {
        if (msg.type == Msg.ADD_USER) {
            addUser(((Integer)msg.arg).intValue());
            return true;
        }
        if (msg.type == Msg.USER_LEFT) {
            userLeft(((Integer)msg.arg).intValue());
            return true;
        }
        if (msg.type == Msg.NEW_TOPIC) {
            topicTF.setText(msg.arg.toString());
            return true;
        }
        return false;
    }

    /**
     * If you close the window, it will call automatically hide() or
     * dispose the commlet (depending if you are in a metacommlet or not).
     * It also sets the topic (and send a NEW_TOPIC message), if the topic
     * is changed in the topic-TextField.
     */
    public boolean handleEvent(Event evt)
    {
        if (evt.id == Event.WINDOW_DESTROY)
        {
            hideCommlet();
            return true;
        }
        if ((evt.id == Event.ACTION_EVENT) && (evt.target == topicTF)) {
            com.setNewTopic(topicTF.getText());
        }
        return super.handleEvent(evt);
    }
}