`TextReaderTest' example program: demonstrates encapsulation of file handling classes
TextReader.java

/*
TextReaderTest

This program defines a class called 'TextReader' which is intended to
simplify reading text files a line at a time. The TextReader class
manages all the intermediate files that are needed for this operation,
so the class that uses it can read a text file without worry about these
details
*/

import java.io.*;

class TextReader 
{
BufferedReader br;

public TextReader(String filename) throws java.io.IOException, java.io.FileNotFoundException
	{
	File aFile =new File(filename);
	FileInputStream fis = new FileInputStream(aFile);
	InputStreamReader isr = new InputStreamReader (fis);
	br = new BufferedReader (isr);
	}

String readLine() throws java.io.FileNotFoundException, java.io.IOException
	{
	return br.readLine();
	}
}


/*
TextReaderTest
This class tests the TextReader by opening a file and reading the first line
from it
*/

class TextReaderTest 
	{
	public static void main (String args[])
		{
		try
			{
			TextReader textReader = new TextReader ("TextReaderTest.java");
			String s = textReader.readLine();
			System.out.println(s);
			}
		catch (Exception e)
			{
			System.out.println(e.toString());
			}
		}
	}