Code example for LineNumberReader

 
        assertEquals("Failed to reset reader", "0", line);
    } 
 
    public void testReadLineSourceThrows() throws IOException { 
        lnr = new LineNumberReader(new Reader() {
            private StringReader delegate = new StringReader("hello\nworld");
            private int calls = 0;
            @Override public void close() throws IOException {} 
            @Override public int read(char[] buf, int offset, int len) throws IOException {
                if (calls++ < 2) {
                    throw new IOException();
                } else { 
                    return delegate.read(buf, offset, len);
                } 
            } 
        }); 
 
        assertEquals(0, lnr.getLineNumber());
        try { 
            lnr.readLine();
            fail();
        } catch (IOException expected) {
        } 
 
        assertEquals(0, lnr.getLineNumber());
        try { 
            lnr.readLine();
            fail();
        } catch (IOException expected) {
        } 
 
        assertEquals(0, lnr.getLineNumber());
        assertEquals("hello", lnr.readLine());
        assertEquals(1, lnr.getLineNumber());
        assertEquals("world", lnr.readLine());
        assertEquals(2, lnr.getLineNumber());
    } 
 
    public void testGetLineNumberAfterEnd() throws IOException { 
        lnr = new LineNumberReader(new StringReader("hello\nworld"));
        assertEquals(0, lnr.getLineNumber());