/*
 * FileExample.java
 *
 * Created on February 26, 2004, 5:19 PM
 */

package datamining;

// for files
import java.io.File;
import java.io.*;
// for FileChooser
import javax.swing.*;
import java.awt.Container;
// for breaking strings up into parts
import java.util.StringTokenizer;

/**
 *
 * @author  redmond
 */
public class FileExample {
    
    /** Creates a new instance of FileExample */
    public FileExample() {
    }
    
    
    /** 
     * get started with a file - including choosing it using the FileChooser,
     * making sure we can read from it
     */
    public static BufferedReader startFile () throws IOException {
        
        //////////////////////////////
        // set up for reading file
        //////////////////////////////
        
        // for using FileChooser
        JFrame empty = new JFrame(); // just create as GUI container so can use file chooser
        Container dummy = empty.getContentPane();
        JFileChooser files;
        
        // for using text files
        File filehandle;
        FileReader fReader;
        BufferedReader bReader;
        
        /// For the FileChooser approach
        empty.setVisible(true);  // display empty JFrame
        files = new JFileChooser();   
        // start open file dialog box
        int result = files.showOpenDialog(dummy);
        if (result == 0) {
            // if successful, read the file
            filehandle = files.getSelectedFile();
            // check if can read
            if (filehandle.exists() && filehandle.canRead() ) {
                // prepare to read it
                fReader = new FileReader(filehandle);
                bReader = new BufferedReader(fReader);
            }
            else {
                throw new IOException(); // signal that we are unable to handle the file
            }
        }
        else {
            throw new IOException(); // signal that we are unable to handle the file
        }
        return bReader;
    }
    
    // demonstrate breaking line into parts
    public static void demoTokenization(String inputLine) {
        StringTokenizer tokenizer;   // for breaking line of text down into parts
        
        // take care of the data in this record
        tokenizer = new StringTokenizer(inputLine,",{}");
        while (tokenizer.hasMoreTokens()) {
            String part = tokenizer.nextToken();
            System.out.println("     token: " + part);
        }
        return;
    }
    
    
    /**
     * @param args the command line arguments
     */
    public static void main(String[] args) {
        
        String line;   // for reading a line of a file into
        BufferedReader bReader = null;  // for getting input from - 
              /// everything else in the set up is hidden from the programmer after this
        
        
        // get set to read
        try {
            // select file and prepare to read
            bReader = startFile();
            // just read junk
            line = bReader.readLine();
            // read until end of file
            while (line != null) {
                // just echo input file
                System.out.println("line: " + line);
                // just to demonstrate - break line into its parts
                // no return - just display to console (because this program 
                // doesn't actually do anything with the input)
                demoTokenization(line);
                line = bReader.readLine();
                                
            }
        }
        catch (IOException ex) {
            System.out.println("Read failed. Exiting ...'");
            System.exit(0);
        }
    }
    
}