content: /*
  * 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
  *
  * .
  *
  */
  package gov2.nist.javax2.sip.parser;
  
  import gov2.nist.core.Token;
  import gov2.nist.javax2.sip.header.*;
  
  import java.text.ParseException;
  
  /**
   * Parser for UserAgent header.
   *
   * @version 1.2 $Revision: 1.15 $ $Date: 2009/07/17 18:58:07 $
   *
   * @author Olivier Deruelle  <br/>
   * @author M. Ranganathan  <br/>
   *
   *
   */
  public class UserAgentParser extends HeaderParser {
  
      /**
       * Constructor
       *
       * @param userAgent -
       *            UserAgent header to parse
       */
      public UserAgentParser(String userAgent) {
          super(userAgent);
      }
  
      /**
       * Constructor
       *
       * @param lexer -
       *            the lexer to use.
       */
      protected UserAgentParser(Lexer lexer) {
          super(lexer);
      }
  
      /**
       * parse the message. Note that we have losened up on the parsing quite a bit because
       * user agents tend to be very bad about specifying the user agent according to RFC.
       *
       * @return SIPHeader (UserAgent object)
       * @throws SIPParseException
       *             if the message does not respect the spec.
       */
      public SIPHeader parse() throws ParseException {
          if (debug)
              dbg_enter("UserAgentParser.parse");
          UserAgent userAgent = new UserAgent();
          try {
              headerName(TokenTypes.USER_AGENT);
              if (this.lexer.lookAhead(0) == '\n')
                  throw createParseException("empty header");
  
              /*
               * BNF User-Agent = "User-Agent" HCOLON server-val *(LWS server-val)
               * server-val = product / comment product = token [SLASH
               * product-version] product-version = token
               */
              while (this.lexer.lookAhead(0) != '\n'
                      && this.lexer.lookAhead(0) != '\0') {
  
                  if (this.lexer.lookAhead(0) == '(') {
                      String comment = this.lexer.comment();
                      userAgent.addProductToken('(' + comment + ')');
                  } else {
                      // product = token [SLASHproduct-version]
                      // product-version = token
                      // The RFC Does NOT allow this space but we are generous in what we accept
  
                      this.getLexer().SPorHT();
  
  
                      String product = this.lexer.byteStringNoSlash();
                      if ( product == null ) throw createParseException("Expected product string");
  
                      StringBuffer productSb = new StringBuffer(product);
                      // do we possibily have the optional product-version?
                      if (this.lexer.peekNextToken().getTokenType() == TokenTypes.SLASH) {
                          // yes
                          this.lexer.match(TokenTypes.SLASH);
                          // product-version
                          // The RFC Does NOT allow this space but we are generous in what we accept
                          this.getLexer().SPorHT();
  
                          String productVersion = this.lexer.byteStringNoSlash();
  
                          if ( productVersion == null ) throw createParseException("Expected product version");
  
                          productSb.append("/");
  
                          productSb.append(productVersion);
                      }
  
                      userAgent.addProductToken(productSb.toString());
                  }
                  // LWS
                  this.lexer.SPorHT();
              }
          } finally {
              if (debug)
                  dbg_leave("UserAgentParser.parse");
          }
  
          return userAgent;
      }
  
  
        public static void main(String args[]) throws ParseException { String
        userAgent[] = { "User-Agent: Softphone/Beta1.5 \n", "User-Agent:Nist/Beta1 (beta version) \n", "User-Agent: Nist UA (beta version)\n",
        "User-Agent: Nist1.0/Beta2 Ubi/vers.1.0 (very cool) \n" ,
        "User-Agent: SJphone/1.60.299a/L (SJ Labs)\n",
        "User-Agent: sipXecs/3.5.11 sipXecs/sipxbridge (Linux)\n"};
  
        for (int i = 0; i < userAgent.length; i++ ) { UserAgentParser parser =
        new UserAgentParser(userAgent[i]); UserAgent ua= (UserAgent)
        parser.parse(); System.out.println("encoded = " + ua.encode()); }
         }
  
  }
  