news.java

Mobile Services

/* Importing the basic packages required by various classes 
	during execution of the program    */
import java.util.Hashtable;
import javax.microedition.midlet.*;
import javax.microedition.lcdui.*;
import javax.microedition.io.*;
import java.util.*;
import java.io.*; 
import java.lang.*;
 
/* Declaration of the class News */
public class News extends MIDlet implements CommandListener
{
	/* Create an object of class Dataparser */
  	DataParser getd;
 
 	/* Declaring  variable for requesting that object to be displayed on the device */
 	private Display displaylist;
 
 	/* Declaring List type variables for storing and displaying list of categories ,
 	   news and news details  */
  	private List category, news, details;
  	
  	/* Declare and create vector type variable for storing news */
  	private Vector vnews = new Vector();
  				
  	/* Declaring variables for Command Buttons and initializing with null */
  	private Command cancelcommand = null;
  	private Command okcommand = null;
  	private Command goback = null;
	private Command exitcommand = null;
	private Command previouscommand = null;
  	private Command backcommand = null;
  	private Command viewcommand = null;
  	private Command startcommand = null;
  
  	/*	Declaring variables for Hashtable and initializing with null  */
  	public Hashtable htable = null;
  	
  	/* Declaring object of Class MainClass */
  	private MainClass lastscreen;
 
 	/* Declaring constructor of Class News */
  	public News(Display displaynews,MainClass obj)
  	{
  		
 		lastscreen = obj;
 		
  		/* Get the current reference of any object which is present at run time for displaying  
  		on the cellpone screen */
		displaylist = displaynews;
  	
		/* Create an object of List type to store the list of Categories */
 		category = new List("Category",List.IMPLICIT);
  
  		/* Registering the List object category for event Handling */
  		category.setCommandListener(this);
  
  		/* Creates an object for Ok command button defined as SCREEN and given the priority 1 */
  		okcommand = new Command("OK",Command.SCREEN,1);
  		
  		/* Creates an object for Cancel command button defined as SCREEN and given the priority 2 */
  		cancelcommand = new Command("Cancel",Command.SCREEN,2);
  		
  		/* Creates an object for Back command button defined as BACK and given the priority 1 */
  		backcommand = new Command("Back",Command.BACK,1);
  
  		/* Creates an object for View command button defined as SCREEN and given the priority 2 */
  		viewcommand = new Command("View",Command.SCREEN,2);
 
  		/* Creates an object for Previous command button defined as BACK and given the priority 1 */
  		previouscommand = new Command("Previous",Command.BACK,1);
  
  		/* Creates an object for Start command button defined as SCREEN and given the priority 2 */
  		startcommand = new Command("Start",Command.SCREEN,2);
  		
  	}
  
  	/* Declarartion of the method startApp */
  	/* Application Starts from this method */
  	public void startApp()
  	{
  		/* Store the path of xml file in url object object as string */
  		String url = new String("http://192.192.168.100/midlet/template/midlet_news.xml");
  		
  		/* Create an object for DataParser class */
  		getd = new DataParser();
  
  		/* Calling the method sourceurl and sending the path of the xml file */
  		getd.sourceurl(url);
  
  		/* Calling the read_category methods for parsing the XML file and inserting 
  		   the records in the vector news */
  		getd.read_category();
  
  		/* Calling  the returnNews method and returning the records in vector vnews */
  		vnews = getd.returnNews();
  		
  		/* Creates an object that implements the Enumeration interface generating a series of elements */ 
  		Enumeration e = vnews.elements();
  		
  		/* The loop execute till any elements are present in Enumeration e object */
  		while (e.hasMoreElements())
  		{
  			/*  append all vector values in List category */
  			category.append( (String)e.nextElement() , null);
  		}
  		
  		/* Displays values of List category on cellphone screen */
  		displaylist.setCurrent(category);
  
  		/* To attach the ok command button with List category */ 
  		category.addCommand(okcommand);
  
  		/* To attach the cancel command button with List category */ 
  		category.addCommand(cancelcommand);
  	}
  	
  	/* Declaring method for eventhandling routines */
  	public void commandAction(Command c, Displayable d)
  	{
  		int index = 0 ;
  		
  		/* if condition is associated with the Ok command button when the user clicks it */
  		if(c == okcommand)
  		{
  			/* Creates an object for hashtable htable */
  			htable = new Hashtable();
  
  			/* get the postion which is selected by the user in the List category */
  			index  = category.getSelectedIndex();
  
  			/* Retrieving the List value into String according to the index number */
  			String st = category.getString(index);
  			
  			/* Storing the path of xml file in url object as string */
  			String url = new String("http://192.192.168.100/midlet/template/midlet_news_det.xml?ctg="+st );
  
  			/* Calling the method sourceurl and sending the path of the xml file */
  			getd.sourceurl(url);
  			
  			/* Calling  the read_record method for parsing XML file and
  			   storing the records into the Hashtable */ 
  			getd.read_news();
  			
  			/* Calling the returnHash_id method and returning the records in hashtable */
  			htable = getd.returnHash_id();
  			
  			/* Create an object news of List type to display the News of the category selected */
  			news = new List("News of " +  category.getString(index), List.IMPLICIT) ;
  			
  			/* Registering the List object news for event Handling */
  			news.setCommandListener(this);
  			
  			/* Creates an object that implements the Enumeration interface generating a series of elements  
  			   and the loop will execute till any element is present in Enumeration e object */
  			for (Enumeration e = htable.keys(); e.hasMoreElements() ;) 
  			{
  				/* appending  hashtable values in List object news */
  				news.append((String)e.nextElement(), null);
  			}
  
  			/* displays List object news on cellphone screen */
  			displaylist.setCurrent(news);
  			
  			/* To attach the Back Command Button with List object news */ 
  			news.addCommand(backcommand);
  		
  			/* To attach the View Command Button with List object news */ 
  			news.addCommand(viewcommand);
  
  		}
  				
  		/* if condition is associated with the Cancel command button when the user clicks it */
  		if(c == cancelcommand)
  		{
  			destroyApp(true);
  			notifyDestroyed();
  			/* The getDisplayObject method takes displayobject as parameter and displays the first
  			   screen of the application  */
  			lastscreen.getDisplayObject(displaylist);
  		}
  
  		/* if condition is associated with the Back command button when the user clicks it */
  		if(c == backcommand )
		{
  			
  			/* displays List object category on cellphone screen */
  			displaylist.setCurrent(category);
  						
  			/* To attach the Ok Command Button with List object category */ 
  			category.addCommand(okcommand);
  						
  			/* To attach the Cancel Command Button with List object category */ 
  			category.addCommand(cancelcommand);
  		}
  
  		/* if condition is associated with the Start Command Button when the user clicks it */
  		if(c == startcommand )
 		{
  					
  			/* displays List object category on cellphone screen */
  			displaylist.setCurrent(category);
  						
  			/* To attach the Ok Command Button with List object category */
  			category.addCommand(okcommand);
  
  			/* To attach the Cancel Command Button with List object category */
  			category.addCommand(cancelcommand);
  		}
  
  		/* if condition is associated with the View Command Button when the user clicks it */
  		if(c == viewcommand)
  		{
  			/* Create an object of List type to store the details of the News */
  			details = new List("Details",List.IMPLICIT);
  			
  			/* declare an String object */
  			String st = "";
  						
  			/* get the postion (index number) which is selected by the user in the List object news  */
  			index  = news.getSelectedIndex();
  
  			/* Retrieving the List value according to the index number */
  			st = news.getString(index);
  			
  			/* Retreiving the hashtable value according to the index number */
  			String hash_id = (String)htable.get(news.getString(index));
  
  			/* Storing the path of xml file in String object url */
  			String url = new String("http://192.192.168.100/midlet/template/midlet_news_description.xml?heading_id="+hash_id);
  			
  			
  			/* Calling the method sourceurl and sending the path of the xml file */
  			getd.sourceurl(url);
  
  			/* Calling  the returnDetails method for parsing XML file and
  			   returning  the record into a String  */ 
  			String st_details = getd.returnDetails(); 		
  
  			/* Adding the String to List Object details */
  			details.append((String)st_details , null);
  
  			/* Registering the List object details for event Handling */
  			details.setCommandListener(this);
  			
  			/* displays List Object details on cellphone screen */
  			displaylist.setCurrent(details);
  			
  			/*  To attach the Previous Command Button with List Object details */
  			details.addCommand(previouscommand);
			
  			/*  To attach the Start Command Button with List Object details */
  			details.addCommand(startcommand);
  
  		}
  
  		/* if condition is associated with previous command button when the user clicks it  */
  		if(c == previouscommand)
  		{
  			/* Registering the List object news for event Handling */
  			news.setCommandListener(this);
  			
  			/* displays List Object news on cellphone screen */
  			displaylist.setCurrent(news);
  			
  			/*  To attach the Back Command Button with List Object news */
  			news.addCommand(backcommand);
  			
  			/*  To attach the Add Command Button with List Object news */		
  			news.addCommand(viewcommand);
  		}
  	}  
  		
  	public void destroyApp(boolean b)
  	{}
  	public void pauseApp()
  	{}		
}