class ByteSequenceLengthFilter {

	public String filter(String base) {
		if ((base == null) || (base.length() < minLength)) {
			return null;
		}
		if (internalIndex >= 0) {
			return base.substring(0, internalIndex);
		}
		int len = base.length();
		return base.substring(len + internalIndex, len);//internalIndex is negative

	}

	public  ByteSequenceLengthFilter(int internalIndex, int minLength);

}