protected static String encodeDocInfo(Map<String, String> info) { if (info == null) { return null; } StringBuilder buf = new StringBuilder(); for (Entry<String, String> e : info.entrySet()) { if (buf.length() > 0) { buf.append(';'); } buf.append(e.getKey()); if (e.getValue() != null) { buf.append(':').append(e.getValue()); } } return buf.length() > 0 ? buf.toString() : null; }