code: public boolean isInNavigation() {
  
          if (m_hasNav == null) {
              // use "lazy initializing"
              Object o1 = getProperties().get(CmsPropertyDefinition.PROPERTY_NAVTEXT);
              Object o2 = getProperties().get(CmsPropertyDefinition.PROPERTY_NAVPOS);
              m_hasNav = Boolean.valueOf(((o1 != null) || (o2 != null)) && !CmsResource.isTemporaryFileName(m_sitePath));
          }
          return m_hasNav.booleanValue();
      }
docs: Returns <code>true</code> if this navigation element is in the navigation,
  <code>false</code> otherwise.<p>
  
  A resource is considered to be in the navigation, if <ol>
  <li>it has the property PROPERTY_NAVTEXT set
  <li><em>or</em> it has the property PROPERTY_NAVPOS set
  <li><em>and</em> it is not a temporary file as defined by {@link CmsResource#isTemporaryFileName(String)}.</ol>
  
  @return <code>true</code> if this navigation element is in the navigation, <code>false</code> otherwise