content: package gov2.nist.javax2.sip.parser.ims;
  /*
  * Conditions Of Use
  *
  * This software was developed by employees of the National Institute of
  * Standards and Technology (NIST), an agency of the Federal Government.
  * Pursuant to title 15 Untied States Code Section 105, works of NIST
  * employees are not subject to copyright protection in the United States
  * and are considered to be in the public domain.  As a result, a formal
  * license is not needed to use the software.
  *
  * This software is provided by NIST as a service and is expressly
  * provided "AS IS."  NIST MAKES NO WARRANTY OF ANY KIND, EXPRESS, IMPLIED
  * OR STATUTORY, INCLUDING, WITHOUT LIMITATION, THE IMPLIED WARRANTY OF
  * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE, NON-INFRINGEMENT
  * AND DATA ACCURACY.  NIST does not warrant or make any representations
  * regarding the use of the software or the results thereof, including but
  * not limited to the correctness, accuracy, reliability or usefulness of
  * the software.
  *
  * Permission to use this software is contingent upon your acceptance
  * of the terms of this agreement
  *
  * .
  *
  */
  import java.text.ParseException;
  
  import javax2.sip.InvalidArgumentException;
  
  import gov2.nist.javax2.sip.header.SIPHeader;
  import gov2.nist.javax2.sip.header.ims.PPreferredService;
  import gov2.nist.javax2.sip.header.ims.ParameterNamesIms;
  import gov2.nist.javax2.sip.parser.HeaderParser;
  import gov2.nist.javax2.sip.parser.Lexer;
  import gov2.nist.javax2.sip.parser.TokenTypes;
  /**
   *
   * @author aayush.bhatnagar
   * Rancore Technologies Pvt Ltd, Mumbai India.
   *
   * Parse this:
   * P-Preferred-Service: urn:urn-7:3gpp-service.exampletelephony.version1
   *
   */
  public class PPreferredServiceParser extends HeaderParser implements TokenTypes{
  
      protected PPreferredServiceParser(Lexer lexer) {
          super(lexer);
      }
  
      public PPreferredServiceParser(String pps)
      {
          super(pps);
      }
  
      /**
       * "The URN consists of a hierarchical service identifier or application
       * identifier, with a sequence of labels separated by periods.The left-most label is
       * the most significant one and is called 'top-level service
       * identifier', while names to the right are called 'sub-services' or
       * 'sub-applications'.
       *
       * For any given service identifier, labels can be removed right-to-left and
       * the resulting URN is still valid, referring a more generic
       * service, with the exception of the top-level service identifier
       * and possibly the first sub-service or sub-application identifier.
       *
       *  Labels cannot be removed beyond a defined basic service, for
       *  example, the label w.x may define a service, but the label w may
       *  only define an assignment authority for assigning subsequent
       *  values and not define a service in its own right.  In other words,
       *  if a service identifier 'w.x.y.z' exists, the URNs 'w.x' and
       *  'w.x.y' are also valid service identifiers, but w may not be a
       *  valid service identifier if it merely defines who is responsible"
       *
       * TODO: PLEASE VALIDATE MY UNDERSTANDING OF THE ABOVE TEXT :)
       * @ranga: Please validate my understanding of the above text in the draft :)
       *         This last para is a little ambiguous.I will only check that atleast
       *         1 sub-service or 1 sub-application is present in the URN declaration.
       *         If not, I throw an exception. I thought of not throwing an exception
       *         and returning whatever was encoded..but the resultant encoding wont
       *         make sense. It would be something like-->
       *         urn:urn-7:3gpp-service OR urn:urn-7:3gpp-application alone with no sub-services
       *         or sub-applications. This is bound to cause an error at the recepient later.
       *
       * Sub-service and Application identifiers are not maintained by IANA and
       * are organization/application dependent (Section 8.2). So we cannot gurantee what lies
       * beyond the first sub-service or sub-application identifier. It should be the responsibility
       * of the application to make sense of the entire URN holistically. We can only check for the
       * standardized part as per the ABNF.
       */
      public SIPHeader parse() throws ParseException {
          if(debug)
              dbg_enter("PPreferredServiceParser.parse");
          try
          {
  
          this.lexer.match(TokenTypes.P_PREFERRED_SERVICE);
          this.lexer.SPorHT();
          this.lexer.match(':');
          this.lexer.SPorHT();
  
          PPreferredService pps = new PPreferredService();
          String urn = this.lexer.getBuffer();
          if(urn.contains(ParameterNamesIms.SERVICE_ID)){
  
             if(urn.contains(ParameterNamesIms.SERVICE_ID_LABEL))
                     {
                      String serviceID = urn.split(ParameterNamesIms.SERVICE_ID_LABEL+".")[1];
  
                       if(serviceID.trim().equals(""))
                          try {
                              throw new InvalidArgumentException("URN should atleast have one sub-service");
                          } catch (InvalidArgumentException e) {
  
                              e.printStackTrace();
                          }
                          else
                      pps.setSubserviceIdentifiers(serviceID);
                     }
             else if(urn.contains(ParameterNamesIms.APPLICATION_ID_LABEL))
                {
                 String appID = urn.split(ParameterNamesIms.APPLICATION_ID_LABEL)[1];
                 if(appID.trim().equals(""))
                      try {
                          throw new InvalidArgumentException("URN should atleast have one sub-application");
                      } catch (InvalidArgumentException e) {
                          e.printStackTrace();
                      }
                      else
                    pps.setApplicationIdentifiers(appID);
                }
             else
             {
                 try {
                  throw new InvalidArgumentException("URN is not well formed");
  
              } catch (InvalidArgumentException e) {
                  e.printStackTrace();
                      }
                    }
            }
  
              super.parse();
              return pps;
          }
          finally{
              if(debug)
                  dbg_enter("PPreferredServiceParser.parse");
          }
  
      }
  }
  