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项目管理软件越来越强大，在甘特图设计中，同时展开多个跨行时间表对象也逐渐成常态化趋势。FlexGantt控件通过使用拦截命令实现此功能。

拦截器方法停止使用单一的常规命令，使用几个常规命令组合成复合命令取代它。 每个命令设置时间跨度为一个基于对象的时间表，实现拖动时间表对象。 前提是构造复合命令拦截器检索列表中的时间表对象，并且这个对象来至选择模型对象层。

源码如下：

setCommandInterceptor(DefaultChangeTimespanCommand.class, new ICommandInterceptor() {
   public boolean intercept(GanttChart gc, com.dlsc.flexgantt.command.ICommand cmd) {
      DefaultChangeTimelineObjectTimespanCommand command = 
        (DefaultChangeTimelineObjectTimespanCommand) cmd;
      TimelineObjectPath objectPath = new TimelineObjectPath(command.getNode().getPath(), 
                                                             command.getTimelineObject(), 
                                                             command.getLayer());
      LayerContainer lc = gc.getLayerContainer();
 
      /*
       * Just an example on how to look up the layer. This is application-specific.
       */
      Layer layer = MyModel.LAYER1;
 
      ITimelineObjectSelectionModel selectionModel = lc.getSelectionModel(planLayer);
      Iterator iter = selectionModel.getSelection();
      List list = new ArrayList();
      while (iter.hasNext()) {
         TimelineObjectPath path = iter.next();
         list.add(path);
      }
      if (list.size() > 1) {
         int result = JOptionPane.showConfirmDialog(gc, 
                                 "Move multiple?", 
                                 "Move",
                                 JOptionPane.YES_NO_CANCEL_OPTION);
         switch (result) {
            case JOptionPane.CANCEL_OPTION :
               return false;
            case JOptionPane.YES_OPTION :
               replanSelection(
                  list, 
                  objectPath, 
                  operationCommand.getOldTimeSpan(), 
                  operationCommand.getNewTimeSpan());
               return false;
            case JOptionPane.NO_OPTION :
               return true;
         }
      }
 
      return true;
   }
 
   private void replanSelection(List list, TimelineObjectPath originalPath, 
                                   ITimeSpan oldSpan, ITimeSpan newSpan) {
      AbstractCompoundCommand comp = new AbstractCompoundCommand("Multi Replan") {};
      long delta = oldSpan.getStartTime() - newSpan.getStartTime();
      for (TimelineObjectPath path : list) {
         ITimeSpan pathSpan = getModel().getTimeSpan(path.getTimelineObject());
         ITimeSpan span = new TimeSpan(pathSpan.getStartTime() - delta, 
                                       pathSpan.getEndTime() - delta);
         comp.addCommand(new DefaultChangeTimelineObjectTimespanCommand(
            (DefaultGanttChartNode) path.getNode(), 
            path.getLayer(), 
            (ITimelineObject) path.getTimelineObject(),
            (DefaultGanttChartModel) getModel(), 
            span, 
            DnDConstants.ACTION_MOVE));
      }
      getCommandStack().execute(comp, 
         new GanttChartProgressMonitor(myGanttChart));
   };
});

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