java.io.LineNumberReader#mark ( )源码实例Demo

private boolean gobbleTo(LineNumberReader reader, String target, boolean throwException) throws IOException, ParseException {
    String line = "";
    reader.mark(255);
    while (line.isEmpty()) {
        line = reader.readLine();
        if (line == null)
            return false;
    }
    if (!line.trim().equals(target)) {
        if (throwException)
            throw new ParseException(target + " not found.", reader.getLineNumber());
        else {
            reader.reset();
            return false;
        }
    }
    return true;
}
 

public void test_markI() throws IOException {
    lnr = new LineNumberReader(new StringReader(text));
    String line;
    lnr.skip(80);
    lnr.mark(100);
    line = lnr.readLine();
    lnr.reset();
    assertTrue("Test 1: Failed to return to marked position.",
            line.equals(lnr.readLine()));

    lnr.close();
    try {
        lnr.mark(42);
        fail("Test 2: IOException expected.");
    } catch (IOException e) {
        // Expected.
    }

    // The spec does not say the mark has to be invalidated
}
 

public void test_reset() throws IOException {
    lnr = new LineNumberReader(new StringReader(text));
    assertEquals("Test 1: Returned incorrect line number;",
            0, lnr.getLineNumber());
    String line = null;
    lnr.mark(100);
    lnr.readLine();
    lnr.reset();
    line = lnr.readLine();
    assertEquals("Test 2: Failed to reset reader", "0", line);

    lnr.mark(100);
    lnr.close();
    try {
        lnr.reset();
        fail("Test 3: IOException expected.");
    } catch (IOException e) {
        // Expected.
    }
}