Thread: Reading Big File analysis

I was searching the prohram to read big file (i.e. size more than 4gb). I got the below program and it reads big files. They say that the program doesn't read the whole file at once. I would like to understand how its achieved in below program
public class BigFile implements Iterable<String>
{
private BufferedReader _reader;

public BigFile(String filePath) throws Exception
{
_reader = new BufferedReader(new FileReader(filePath));
}

public void Close()
{
try
{
_reader.close();
}
catch (Exception ex) {}
}

public Iterator<String> iterator()
{
return new FileIterator();
}

private class FileIterator implements Iterator<String>
{
private String _currentLine;

public boolean hasNext()
{
try
{
_currentLine = _reader.readLine();
}
catch (Exception ex)
{
_currentLine = null;
ex.printStackTrace();
}

return _currentLine != null;
}

public String next()
{
return _currentLine;
}

public void remove()
{
}
}
}

Here’s how you might use it:
BigFile file = new BigFile("C:\Temp\BigFile.txt");

for (String line : file)
System.out.println(line);

Please Edit your post and wrap your code with[code=java]<YOUR CODE HERE>[/code] to get highlighting

the program doesn't read the whole file at once

Unless the file has only one line, then the program reads the file one line at a time using the readLine() method.