code: private static String getHeaderParam( final String value, final String paramName ) {
          if( value == null || value.length() == 0 )
              return null;
  
          final int length = value.length();
          int start = value.indexOf(';') + 1;
          if( start == 0 || start == length )
              return null;
  
          int end = value.indexOf(';', start);
          if( end == -1 )
              end = length;
  
          while( start < end ) {
              int nameEnd = value.indexOf('=', start);
              if( nameEnd != -1 && nameEnd < end && paramName.equals(value.substring(start, nameEnd).trim()) ) {
                  String paramValue = value.substring(nameEnd + 1, end).trim();
                  int valueLength = paramValue.length();
                  if( valueLength != 0 )
                      if( valueLength > 2 && '"' == paramValue.charAt(0) && '"' == paramValue.charAt(valueLength - 1) )
                          return paramValue.substring(1, valueLength - 1);
                      else
                          return paramValue;
              }
  
              start = end + 1;
              end = value.indexOf(';', start);
              if( end == -1 )
                  end = length;
          }
  
          return null;
      }
docs: Get parameter value from header value
  
  @param value
  @param paramName
  @return parameter value or null if none