code: public void setExplorerResource(String value, CmsObject cms) {
  
          if (value == null) {
              return;
          }
          // get the current explorer mode
          String mode = getExplorerMode();
          if (mode == null) {
              mode = CmsWorkplace.VIEW_EXPLORER;
          }
          if (CmsWorkplace.VIEW_EXPLORER.equals(mode)) {
              // append the current site to the key when in explorer view mode
              mode += "_" + getSite() + "/";
          }
  
          // set the resource for the given mode
          if (value.startsWith(CmsResource.VFS_FOLDER_SYSTEM + "/")
              && (!value.startsWith(m_currentSite))
              && (!CmsWorkplace.VIEW_GALLERY.equals(getExplorerMode()))) {
              // restrict access to /system/
              m_explorerResource.put(mode, "/");
          } else {
              if (cms != null) {
                  // Validation with read resource has 2 advantages:
                  // 1: Normalization of the path: a missing trailing slash is not fatal.
                  // 2: existence is verified.
                  try {
                      CmsResource resource = cms.readResource(value);
                      value = cms.getSitePath(resource);
                  } catch (CmsException cme) {
                      // nop
                  }
              }
              m_explorerResource.put(mode, value);
          }
      }
docs: Sets the current resource to be displayed in the explorer.<p>
  
  @param value the current resource to be displayed in the explorer
  
  @param cms needed for validation / normalization of the given path