import org.apache.hadoop.eclipse.dfs.DFSActions; //导入依赖的package包/类
public void run(IAction action) {

    // Ignore non structured selections
    if (!(this.selection instanceof IStructuredSelection))
      return;

    // operate on the DFS asynchronously to prevent blocking the main UI
    final IStructuredSelection ss = (IStructuredSelection) selection;
    final String actionId = action.getActionDefinitionId();
    Display.getDefault().asyncExec(new Runnable() {
      public void run() {
        try {
          switch (DFSActions.getById(actionId)) {
            case DELETE: {
              delete(ss);
              break;
            }
            case OPEN: {
              open(ss);
              break;
            }
            case MKDIR: {
              mkdir(ss);
              break;
            }
            case UPLOAD_FILES: {
              uploadFilesToDFS(ss);
              break;
            }
            case UPLOAD_DIR: {
              uploadDirectoryToDFS(ss);
              break;
            }
            case REFRESH: {
              refresh(ss);
              break;
            }
            case DOWNLOAD: {
              downloadFromDFS(ss);
              break;
            }
            case RECONNECT: {
              reconnect(ss);
              break;
            }
            case DISCONNECT: {
              disconnect(ss);
              break;
            }
            default: {
              System.err.printf("Unhandled DFS Action: " + actionId);
              break;
            }
          }

        } catch (Exception e) {
          e.printStackTrace();
          MessageDialog.openError(Display.getDefault().getActiveShell(),
              "DFS Action error",
              "An error occurred while performing DFS operation: "
                  + e.getMessage());
        }
      }
    });
  }