// FILE HANDLING UTILITY CLASS
// Frans Coenen
// University of Liverpool
// 20 April 2013

import java.io.*; 			// File and PrintWriter classes
import javax.swing.*;		// Contains JFileChooser class

class FileHandlingUtility extends JFrame {

	// ------------------- FIELDS ------------------------
	
	/** Instance of PrintWriter class */
    private PrintWriter fileOutput = null;
    /** File instance for output. */
    private File outputFileName = null;
    /** The file name. */
    private String fileName = null;
    
    // ------------------- CONSTRUCTORS ------------------------
    
    /* ------- Default ------ */
    
    // ------------------- OUTPUT FILE METHODS ------------------------
    
	/** Opens the output file ready to write data to.
    @return true if file succesfully opened, and false otherwise. */

    public boolean openOutputFile() {
		// Display file dialog box
		JFileChooser fileChooser = new JFileChooser();
		fileChooser.setFileSelectionMode(JFileChooser.FILES_ONLY);
		int result = fileChooser.showSaveDialog(this);

		// If cancel button selected return
		if (result == JFileChooser.CANCEL_OPTION) return(false);

		// Obtain selected file
		outputFileName = fileChooser.getSelectedFile();

		// Dispaly error if invalid
		if (outputFileName ==  null || outputFileName.getName().equals("")) {
	    	JOptionPane.showMessageDialog(this,"Invalid File name",
				"Invalid File name.",JOptionPane.ERROR_MESSAGE);
	    	return(false);
	    	}
		else {
   	    	try {
				fileOutput = new PrintWriter(new FileWriter(outputFileName));
	 			fileName   = outputFileName.getName();
	 			return(true);
				}
	    	catch(IOException ioException) {
	    		JOptionPane.showMessageDialog(this,"Error opening File",
			 					"Error",JOptionPane.ERROR_MESSAGE);
      			return(false);
				}
	    	}
		}
		
	// ------------------- GET METHODS ------------------------
	
	/** Get PrintWriter object if one has been created.
	@return The PrintWriter objet. */
	
	public PrintWriter getfileOutput() {
		return(fileOutput);	
		}
	
	/** Get file name for opened file.
	@return The file name. */
	
	public String getfileName() {
		return(fileName);	
		}
	}