Edit/Save Text File - Problems

[ryanlbowen]

Hello all,

I am writing a little program that should simply add a title and description to an existing text file. However, my problem is that every time I enter a title and description, it overwrites everything in the program.

Here is my code -any clues as to what's wrong?

public class reference {

	/**
	 * @param args
	 */
	
	public static int countLines (File file) throws IOException {
		
		int lineCount = 0;
		Reader reader = new InputStreamReader(new FileInputStream(file));
		
		char[] buffer = new char[5000];
			
			for ( int charsRead = reader.read(buffer); charsRead >= 0; charsRead = reader.read(buffer) ) {
				
				for (int charIndex = 0; charIndex < charsRead; charIndex++ ) {
					
					if ( buffer[charIndex] == '\n' )
						
						lineCount++;
				}
			}
			
			reader.close();
			return lineCount;
		
	}
	
	
	public static void main(String[] args) {
		// TODO Auto-generated method stub

		
		String title = "";
		String test = "";
		String descrip = ""; 
		
		for ( int count=0; count < 1137; count++ ) {
			
			test = JOptionPane.showInputDialog(null, "Entry Title: ");
			
				if ( !test.equalsIgnoreCase("abort") ) {
					title = test;
				}
				
				else {
					
					count = 1138;
					
					try
			        {
			            JOptionPane.showMessageDialog(null, countLines(new File("reference.txt")));
			        }
			        catch (Exception e)
			        {
			            System.out.println("Problem, exception = " + e);
			            e.printStackTrace(System.out);
			        }
			        
			        System.exit(0);
			        
				}
							
			
			descrip = JOptionPane.showInputDialog(null, "Entry Description: ");
						
			JOptionPane.showMessageDialog(null, title + ": \n" + descrip);
		
				try{
				
					FileWriter entry = new FileWriter("reference.txt");
					BufferedWriter out = new BufferedWriter(entry);
				
					out.write(title + ": " + descrip + "\n");
				
					out.close();
					    		    	    
				}catch (Exception e){
					System.err.println("Error: " + e.getMessage());
				}
		
			}
		
		}
		
}

[Fubarable]

Do understand that when you are writing to a file, you overwrite that file, that especially when writing to the beginning of a file, that there's no way for the operating system or the disk hardware to magically move the old bits over?

So with this in mind, after your BufferedWriter writes the title and description, where do you write out the remaining contents of the file? The contents that you will need to read in first?

[ryanlbowen]

Ok - so you're saying that I need to copy everything, add the new title and description, and then dump it all into a new file?

I'd love to just add the string to the end of the text file...

Sorry...I'm not that great at this - but thanks for the help :-)

[RamyaSivakanth]

Hi,
To FileWriter constructor, set append flag to true.Then content will be appended.

Gothru the api

FileWriter(String fileName, boolean append)
Constructs a FileWriter object given a file name with a boolean indicating whether or not to append the data written.

[Fubarable]

Hi,
To FileWriter constructor, set append flag to true.Then content will be appended.

As I understand the original problem, he is adding text to the beginning of the file. If so, this suggestion above won't work (and is why I didn't suggest it initially). He'll have to stream through the file writing to a different file as he reads, then re-name the newly written file to the old file when he's done.

[ryanlbowen]

Thanks for your help guys. Actually, appending to the end is fine. Sorry I didn't make that clearer.

I'll try the FileWriter constuctor - thanks!

[RamyaSivakanth]

Hi Ryanlbowen,
Be specific with ur requirement from next time.

Hi Fubarable,
I'm able to get what u are trying to say.U guys are making me to learn a lot and helping me to give solutions.

-Regards
Ramya

[ryanlbowen]

OK. Sorry for all the trouble, but I have added this (I think) and it's still overwriting the text. :-/

public static void FileWriter (String file, boolean append) {
		
		try {
			
			FileWriter entry = new FileWriter("reference.txt");
			BufferedWriter out = new BufferedWriter(entry);
		
			out.write( "\n" + file + "\n" );
		
			out.close();
			    		    	    
		}catch (Exception e){
			System.err.println("Error: " + e.getMessage());
		}
		
	}

and then this is Main

				boolean append = true;
				FileWriter(file, append);

I'm really sorry - I haven't Java programmed in some time...

[RamyaSivakanth]

Hi,
Gothru the corrected piece of code.It should work.

try
{
  FileWriter entry = new FileWriter("reference.txt",true);
  BufferedWriter out = new BufferedWriter(entry);
  out.append(title + ": " + descrip + "\n");
  out.close();
    	    
}catch (Exception e)
{
   System.err.println("Error: " + e.getMessage());
}

[ryanlbowen]

Thanks so much! This works perfectly.