AxisContainerEditPolicy.java

package info.limpet.stackedcharts.ui.editor.policies;

import info.limpet.stackedcharts.model.Dataset;
import info.limpet.stackedcharts.model.DependentAxis;
import info.limpet.stackedcharts.ui.editor.commands.AddDatasetsToAxisCommand;
import info.limpet.stackedcharts.ui.editor.commands.DeleteDatasetsFromAxisCommand;
import info.limpet.stackedcharts.ui.editor.commands.MoveAxisCommand;
import info.limpet.stackedcharts.ui.editor.parts.AxisEditPart;
import info.limpet.stackedcharts.ui.editor.parts.DatasetEditPart;

import java.util.List;

import org.eclipse.draw2d.ColorConstants;
import org.eclipse.draw2d.IFigure;
import org.eclipse.emf.common.util.EList;
import org.eclipse.gef.EditPart;
import org.eclipse.gef.EditPolicy;
import org.eclipse.gef.Request;
import org.eclipse.gef.commands.Command;
import org.eclipse.gef.commands.CompoundCommand;
import org.eclipse.gef.editpolicies.ContainerEditPolicy;
import org.eclipse.gef.requests.CreateRequest;
import org.eclipse.gef.requests.GroupRequest;

public class AxisContainerEditPolicy extends ContainerEditPolicy implements
    EditPolicy
{

  @Override
  public EditPart getTargetEditPart(Request request)
  {
    if (REQ_ADD.equals(request.getType()))
    {
      return getHost();
    }
    return super.getTargetEditPart(request);
  }

  @Override
  protected Command getOrphanChildrenCommand(GroupRequest request)
  {
    @SuppressWarnings("rawtypes")
    List toRemove = request.getEditParts();
    Dataset[] datasets = new Dataset[toRemove.size()];
    int i = 0;
    for (Object o : toRemove)
    {
      datasets[i++] = (Dataset) ((DatasetEditPart) o).getModel();
    }
    return new DeleteDatasetsFromAxisCommand((DependentAxis) getHost()
        .getModel(), datasets);
  }

  @Override
  protected Command getCreateCommand(CreateRequest request)
  {
    // TODO Auto-generated method stub
    return null;
  }

  @Override
  protected Command getAddCommand(GroupRequest request)
  {
    @SuppressWarnings("rawtypes")
    List toAdd = request.getEditParts();

    final Command res;

    // have a peek, to see if it's a dataset, or an axis
    if (toAdd.size() == 0)
    {
      // nothing selected. don't bother
      res = null;
    }
    else
    {
      Object first = toAdd.get(0);
      if (first instanceof DatasetEditPart)
      {
        Dataset[] datasets = new Dataset[toAdd.size()];
        int i = 0;
        for (Object o : toAdd)
        {
          datasets[i++] = (Dataset) ((DatasetEditPart) o).getModel();
        }
        res =
            new AddDatasetsToAxisCommand((DependentAxis) getHost().getModel(),
                datasets);
      }
      else if (first instanceof AxisEditPart)
      {
        CompoundCommand compoundCommand = new CompoundCommand();
        res = compoundCommand;
        // find the listing we belong to
        DependentAxis axis = (DependentAxis) getHost().getModel();

        // find out which list (min/max) this axis is currently on
        EList<DependentAxis> destination = MoveAxisCommand.getHostListFor(axis);

        int indexOfHost = destination.indexOf(axis);
        int newindex = indexOfHost--;
        if (newindex < 0)
          newindex = 0;

        // ok, did we find it?
        if (destination != null)
        {
          for (Object o : toAdd)
          {
            if (o instanceof AxisEditPart)
            {
              compoundCommand.add(new MoveAxisCommand(destination,
                  (DependentAxis) ((AxisEditPart) o).getModel(), newindex));
              newindex++;
            }
          }
        }
      }
      else
      {
        // it's not a type that we're interested in. don't bother
        res = null;
      }
    }
    
    return res;
  }

  @Override
  public void showTargetFeedback(Request request)
  {
    // highlight the Axis when user is about to drop a dataset on it
    if (REQ_ADD.equals(request.getType()))
    {
      AxisEditPart axisEditPart = (AxisEditPart) getHost();
      IFigure figure = axisEditPart.getFigure();
      figure.setBackgroundColor(ColorConstants.lightGray);
    }
  }

  @Override
  public void eraseTargetFeedback(Request request)
  {
    // remove the highlight
    if (REQ_ADD.equals(request.getType()))
    {
      AxisEditPart axisEditPart = (AxisEditPart) getHost();
      IFigure figure = axisEditPart.getFigure();
      figure.setBackgroundColor(AxisEditPart.BACKGROUND_COLOR);
    }
  }

  

}