line string reader in J2ME : String « Date Type « Android

line string reader in J2ME



 * line string reader in J2ME
 * @author celon
public class TextFileReader extends Reader {
  private InputStream is;
  private byte[] buffer = new byte[65535];
  private int index = buffer.length;
  private StringBuffer sb = new StringBuffer();
  private boolean fileEOF = false;
  private int scanEndIndex;
  private static final String UTF_ENCODE = "UTF-8";
  private static final char endChar = '\n';

   * @param args
  public static void main(String[] args) {
    // TODO Auto-generated method stub


  public TextFileReader(InputStream _is) {
    is = _is;

  public void close() throws IOException {

   * never use it
  public int read(char[] cbuf, int off, int len) throws IOException {
    return 0;

   * read a line from text file, return null when get EOF
   * @return
   * @throws IOException
  public String readLine() throws IOException {
    boolean endFound = false;
    while (!endFound) {
      //add string to buffer until found endChar
      if (!fileEOF) {
        scanEndIndex = buffer.length;
        if (index >= buffer.length) {
          //reload from file and reset index
          int bufferByteNum = readToBuffer();
          index = 0;
          if (bufferByteNum < buffer.length) {
            scanEndIndex = bufferByteNum;
            fileEOF = true;
      for (; index < scanEndIndex; index++) {
        if (buffer[index] == endChar) {
          //found line end
          endFound = true;
          //skip endChar
          return returnBuffer();
        } else {
          //append to buffer
          sb.append((char) (buffer[index]));
      if (endFound) {
        return returnBuffer();
      } else if (fileEOF) {
        return returnBuffer();
    return null;

  private int readToBuffer() throws IOException {
    int result =;
    return result;

  private String returnBuffer() {
    if (sb.length() == 0)
      return null;
    byte[] data = new byte[sb.length()];
    for (int i = 0; i < data.length; i++) {
      data[i] = (byte) (sb.charAt(i));
    String result = null;
    try {
      result = new String(data, UTF_ENCODE);
    } catch (UnsupportedEncodingException e) {
    //clear buffer
    sb.delete(0, sb.length());
    return result;


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