/** Whether has parameter <i>param_name</i> */
public boolean hasParameter(String param_name)
{ char[] name_separators={'=', ' ', '\t', '\r', '\n'};
SipParser par=new SipParser(value);
par.skipString(); // skip the auth_scheme
par.skipWSPCRLF();
while (par.hasMore())
{ String name=par.getWord(name_separators);
if (name.equals(param_name)) return true;
par.goToCommaHeaderSeparator().skipChar().skipWSPCRLF();