rssreadermidlet.java

rss readerr ss readerr ss reader

/**
 * RssReaderMIDlet.java
 */

package RssReader;

import java.util.*;
import javax.microedition.midlet.*;
import javax.microedition.lcdui.*;

/**
 * RSS feed reader MIDlet
 *
 * RssReaderMIDlet is an application that can read RSS feeds. User can store
 * multiple RSS feeds as bookmarks into application's record store.
 */
public class RssReaderMIDlet extends MIDlet
        implements CommandListener, Runnable {
    
    // Attributes
    private Display     m_display;          // The display for this MIDlet
    private Settings    m_settings;         // The settings
    private Hashtable   m_rssFeeds;         // The bookmark URLs
    private Thread      m_netThread;        // The thread for networking
    private boolean     m_getPage;          // The noticy flag for HTTP
    
    // Currently selected bookmark
    private int             m_curBookmark;  // The currently selected item
    private RssFeedParser   m_curRssParser; // The currently selected RSS
    
    // GUI items
    private List        m_bookmarkList;     // The bookmark list
    private List        m_headerList;       // The header list
    private Form        m_itemForm;         // The item form
    private Form        m_addNewBMForm;     // The add new bookmark form
    private Form        m_loadForm;         // The "loading..." form
    private TextField   m_bmName;           // The RSS feed name field
    private TextField   m_bmURL;            // The RSS feed URL field
    
    // Commands
    private Command     m_addOkCmd;         // The OK command
    private Command     m_addCancelCmd;     // The Cancel command
    private Command     m_exitCommand;      // The exit command
    private Command     m_addNewBookmark;   // The add new bookmark command
    private Command     m_openBookmark;     // The open bookmark command
    private Command     m_editBookmark;     // The edit bookmark command
    private Command     m_delBookmark;      // The delete bookmark command
    private Command     m_backCommand;      // The back to header list command
    private Command     m_openHeaderCmd;    // The open header command
    private Command     m_backHeaderCmd;    // The back to bookmark list command
    private Command     m_updateCmd;        // The update headers command
    
    
    public RssReaderMIDlet() {
        m_display = Display.getDisplay(this);
        
        /** Initialize commands */
        m_addOkCmd          = new Command("OK", Command.OK, 1);
        m_addCancelCmd      = new Command("Cancel", Command.CANCEL, 2);
        m_backCommand       = new Command("Back", Command.SCREEN, 1);
        m_exitCommand       = new Command("Exit", Command.SCREEN, 4);
        m_addNewBookmark    = new Command("Add new", Command.SCREEN, 2);
        m_openBookmark      = new Command("Open", Command.SCREEN, 1);
        m_editBookmark      = new Command("Edit", Command.SCREEN, 2);
        m_delBookmark       = new Command("Delete", Command.SCREEN, 3);
        m_openHeaderCmd     = new Command("Open", Command.SCREEN, 1);
        m_backHeaderCmd     = new Command("Back", Command.SCREEN, 2);
        m_updateCmd         = new Command("Update", Command.SCREEN, 2);
        
        m_getPage = false;
        m_curBookmark = -1;
        
        /** Initialize GUI items */
        initializeBookmarkList();
        initializeAddBookmarkForm();
        initializeHeadersList();
        initializeLoadingForm();
        
        m_display.setCurrent(m_bookmarkList);
        
        /** Initialize thread for http connection operations */
        m_netThread = new Thread(this);
        m_netThread.start();
    }
    
    /** Load bookmarks from record store */
    private void initializeBookmarkList() {
        try {
            m_bookmarkList = new List("Bookmarks", List.IMPLICIT);
            m_bookmarkList.addCommand( m_exitCommand );
            m_bookmarkList.addCommand( m_addNewBookmark );
            m_bookmarkList.addCommand( m_openBookmark );
            m_bookmarkList.addCommand( m_editBookmark );
            m_bookmarkList.addCommand( m_delBookmark );
            m_bookmarkList.setCommandListener( this );
            
            boolean stop = false;
            int i = 1;
            
            m_rssFeeds = new Hashtable();
            m_settings = Settings.getInstance(this);
            String bms = m_settings.getStringProperty("bookmarks", "");
            
            if(bms.length()>0) {
                do{
                    System.out.println("bms: " + bms);
                    String part = "";
                    if(bms.indexOf("^")>0)
                        part = bms.substring(0, bms.indexOf("^"));
                    bms = bms.substring(bms.indexOf("^")+1);
                    RssFeed bm = new RssFeed( part );
                    if(bm.getName().length()>0){
                        m_bookmarkList.append(bm.getName(),null);
                        m_rssFeeds.put(bm.getName(), bm);
                    }
                    if( part.length()==0)
                        stop = true;
                }while(!stop);
            }
        } catch(Exception e) {
            
        }
    }
    
    /** Initialize loading form */
    private void initializeLoadingForm() {
        m_loadForm = new Form("Loading");
        m_loadForm.append("Loading RSS feed...");
        m_loadForm.addCommand( m_backHeaderCmd );
        m_loadForm.setCommandListener( this );
    }
    
    /** Initialize bookmark adding form */
    private void initializeAddBookmarkForm() {
        m_addNewBMForm = new Form("New bookmark");
        m_bmName = new TextField("Name", "", 35, TextField.ANY);
        m_bmURL  = new TextField("URL", "http://", 64, TextField.URL);
        m_addNewBMForm.append( m_bmName );
        m_addNewBMForm.append( m_bmURL );
        m_addNewBMForm.addCommand( m_addOkCmd );
        m_addNewBMForm.addCommand( m_addCancelCmd );
        m_addNewBMForm.setCommandListener(this);
    }
    
    /** Run method is used to get RSS feed with HttpConnection */
    public void run(){
        /* Use networking if necessary */
        long lngStart;
        long lngTimeTaken;
        while(true) {
            try {
                if( m_getPage ) {
                    try {
                        /** Get RSS feed */
                        m_curRssParser.parseRssFeed();
                        fillHeadersList();
                        m_display.setCurrent( m_headerList );
                    }catch(Exception e) {
                        /** Error while parsing RSS feed */
                        System.out.println("Error: " + e.getMessage());
                        m_loadForm.append("\nError parsing RSS feed on:\n" + 
                                m_curRssParser.getRssFeed().getUrl());
                        m_display.setCurrent( m_loadForm );
                    }
                    m_getPage = false;
                }
                lngStart = System.currentTimeMillis();
                lngTimeTaken = System.currentTimeMillis()-lngStart;
                if(lngTimeTaken<100)
                    m_netThread.sleep(75-lngTimeTaken);
            } catch (InterruptedException e) {
                break;
            }
        }
    }
    
    /** Save bookmark into record store and bookmark list */
    private void SaveBookmark(){
        String name = "";
        String url  = "";
        name = m_bmName.getString();
        url  = m_bmURL.getString();
        RssFeed bm = new RssFeed(m_bmName.getString(), m_bmURL.getString());
        String key;
        if( m_curBookmark>=0 ){
            m_bookmarkList.set(m_curBookmark, bm.getName(), null);
        } else{
            m_bookmarkList.insert(m_bookmarkList.size(), bm.getName(), null);
        }
        m_rssFeeds.put(bm.getName(), bm);
        System.out.println("bm: " + bm.getStoreString());
    }
    
    /** Fill RSS header list */
    private void fillHeadersList() {
        while(m_headerList.size()>0)
            m_headerList.delete(0);
        for(int i=0; i<m_curRssParser.getRssFeed().getItems().size(); i++){
            RssFeed feed = m_curRssParser.getRssFeed();
            RssItem r = (RssItem)feed.getItems().elementAt(i);
            m_headerList.append( r.getTitle(), null );
        }
    }
    
    /** Initialize RSS headers list */
    private void initializeHeadersList() {
        m_headerList = new List("Headers", List.IMPLICIT);
        m_headerList.addCommand(m_openHeaderCmd);
        m_headerList.addCommand(m_backHeaderCmd);
        m_headerList.addCommand(m_updateCmd);
        m_headerList.setCommandListener(this);
    }
    
    /** Initialize RSS item form */
    private void initializeItemForm(RssItem item) {
        if( m_itemForm == null){
            System.out.println("Create new item form");
            m_itemForm = new Form( item.getTitle() );
            m_itemForm.addCommand( m_backCommand );
            m_itemForm.setCommandListener(this);
        }
        while(m_itemForm.size()>0) {
            System.out.println("Delete item");
            m_itemForm.delete(0);
        }
        m_itemForm.append(new StringItem("Title:", 
                item.getTitle()));
        m_itemForm.append(new StringItem("Description:", 
                item.getDescription()));
        m_itemForm.append(new StringItem("Link:", 
                item.getLink()));
    }
    
    /**
     * Start up the Hello MIDlet by creating the TextBox and associating
     * the exit command and listener.
     */
    public void startApp() {
        m_display.setCurrent( m_bookmarkList );
    }
    
    /**
     * Pause is a no-op since there are no background activities or
     * record stores that need to be closed.
     */
    public void pauseApp() {
    }
    
    /**
     * Destroy must cleanup everything not handled by the garbage collector.
     * In this case there is nothing to cleanup.
     */
    public void destroyApp(boolean unconditional) {
    }
    
    /** Save bookmarks to record store */
    public void saveBookmarks() {
        String bookmarks = "";
        for( int i=0; i<m_bookmarkList.size(); i++) {
            String name = m_bookmarkList.getString(i);
            RssFeed rss = (RssFeed)m_rssFeeds.get( name );
            if( name.length()>0)
                bookmarks += rss.getName() + "|" + rss.getUrl() + "^";
        }
        m_settings.setStringProperty("bookmarks",bookmarks);
    }
    
    /** Update RSS feed's headers */
    private void updateHeaders() {
        initializeLoadingForm();
        m_display.setCurrent( m_loadForm );
        if(m_curRssParser.getRssFeed().getUrl().length()>0) {
            m_getPage = true;
        }
    }
    
    /** Respond to commands */
    public void commandAction(Command c, Displayable s) {
        /** Add new RSS feed bookmark */
        if( c == m_addNewBookmark ){
            m_curBookmark = -1;
            m_bmName.setString("");
            m_bmURL.setString("http://");
            m_display.setCurrent( m_addNewBMForm );
        }
        
        /** Exit from MIDlet and save bookmarks */
        if( c == m_exitCommand ){
            try {
                saveBookmarks();
                m_settings.save(false);
            } catch(Exception e) {}
            destroyApp(false);
            notifyDestroyed();
        }
        
        /** Save currently edited (or added) RSS feed's properties */
        if( c == m_addOkCmd ){
            SaveBookmark();
            m_display.setCurrent( m_bookmarkList );
        }
        
        /** Cancel currently edited (or added) RSS feed's properties */
        if( c == m_addCancelCmd ){
            m_display.setCurrent( m_bookmarkList );
        }
        
        /** Edit currently selected RSS feed bookmark */
        if( c == m_editBookmark ){
            if( m_bookmarkList.size()>0 ){
                m_curBookmark = m_bookmarkList.getSelectedIndex();
                RssFeed bm = (RssFeed)m_rssFeeds.get(
                        m_bookmarkList.getString(m_curBookmark));
                m_bmName.setString( bm.getName() );
                m_bmURL.setString(  bm.getUrl() );
                m_display.setCurrent( m_addNewBMForm );
            }
        }
        
        /** Delete currently selected RSS feed bookmark */
        if( c == m_delBookmark ){
            if( m_bookmarkList.size()>0 ){
                m_curBookmark = m_bookmarkList.getSelectedIndex();
                m_bookmarkList.delete( m_curBookmark );
            }
        }
        
        /** Open RSS feed bookmark */
        if( c == m_openBookmark || (c == List.SELECT_COMMAND && 
                m_display.getCurrent()==m_bookmarkList)){
            if( m_bookmarkList.size()>0 ){
                m_curBookmark = m_bookmarkList.getSelectedIndex();
                
                RssFeed feed = (RssFeed)m_rssFeeds.get(
                        m_bookmarkList.getString(m_curBookmark));
                m_curRssParser = new RssFeedParser( feed );
                if( m_curRssParser.getRssFeed().getItems().size()==0 ) {
                    /** Update RSS feed headers only if this is a first time */
                    updateHeaders();
                } else {
                    /**
                     * Show currently selected RSS feed
                     * headers without updating them
                     */
                    fillHeadersList();
                    m_display.setCurrent( m_headerList );
                }
            }
        }
        
        /** Open RSS feed's selected topic */
        if( c == m_openHeaderCmd || (c == List.SELECT_COMMAND &&
                m_display.getCurrent()==m_headerList)) {
            if( m_headerList.size()>0 ) {
                RssFeed feed = m_curRssParser.getRssFeed();
                RssItem item = (RssItem) feed.getItems().elementAt(
                        m_headerList.getSelectedIndex() );
                initializeItemForm( item );
                m_display.setCurrent( m_itemForm );
            }
        }
        
        /** Get back to RSS feed headers */
        if( c == m_backCommand ){
            m_display.setCurrent( m_headerList );
        }
        
        /** Get back to RSS feed bookmarks */
        if( c == m_backHeaderCmd ){
            m_display.setCurrent( m_bookmarkList );
        }
        
        /** Update currently selected RSS feed's headers */
        if( c == m_updateCmd ) {
            updateHeaders();
        }
    }
}