code: public String getURL()
      {
          validateNotEmpty( m_groupId, true, "Group" );
          validateNotEmpty( m_artifactId, true, "Artifact" );
          final StringBuilder url = new StringBuilder();
          url.append( "mvn:" ).append( m_groupId ).append( "/" ).append( m_artifactId );
          if( m_version != null || m_type != null || m_classifier != null )
          {
              url.append( "/" );
          }
          if( m_version != null )
          {
              url.append( m_version );
          }
          if( m_type != null || m_classifier != null )
          {
              url.append( "/" );
          }
          if( m_type != null )
          {
              url.append( m_type );
          }
          if( m_classifier != null )
          {
              url.append( "/" ).append( m_classifier );
          }
          return url.toString();
      }
docs: {@inheritDoc}
  
  @throws IllegalArgumentException - If group id is null or empty
  - If artifact id is null or empty