code: protected final PreviousPageInfo getPreviousPageInfo()
      {
          checkPreviousPageInfoDisabled();
  
          PreviousPageInfo ret = _previousPageInfo != null ? _previousPageInfo : _currentPageInfo;
  
          if ( ret != null )
          {
              ret.reinitialize( this ); // Allows it to reconstruct transient members after session failover
          }
  
          return ret;
      }
docs: Get information about the previous page (in this page flow) shown to the user.  The previous
  page is the one shown before the most recent page.
  <p>
  <i>Note: if the current page flow does not use a
  {@link org.apache.beehive.netui.pageflow.annotations.Jpf.Forward &#64;Jpf.Forward},
  {@link org.apache.beehive.netui.pageflow.annotations.Jpf.SimpleAction &#64;Jpf.SimpleAction}, or
  {@link org.apache.beehive.netui.pageflow.annotations.Jpf.ConditionalForward &#64;Jpf.ConditionalForward}
  with <code>navigateTo={@link org.apache.beehive.netui.pageflow.annotations.Jpf.NavigateTo#currentPage currentPage}</code>
  or <code>navigateTo={@link org.apache.beehive.netui.pageflow.annotations.Jpf.NavigateTo#previousPage previousPage}</code>,
  then this method will always return </i><code>null</code><i> by default.  To enable it in this situation, add the
  following method to the page flow:</i><br>
  </blockquote>
  
  @return a PreviousPageInfo with information about the previous page shown to the user.
  @see #getCurrentPageInfo
  @see #getPreviousActionInfo
  @see #getPreviousActionURI
  @see #getPreviousFormBean
  @see #getPreviousForwardPath
  @see #getCurrentForwardPath