7.9 XmlHeadFactory，用来产生与模型对应的xmlhead

package custom.gef.editor.model;

import custom.gef.editor.model.connection.MessageFromModel;
import custom.gef.editor.model.connection.MessageToModel;
import custom.gef.editor.model.port.PortGuideModel;
import custom.gef.editor.model.port.PortOperationModel;

public class XmlHeadFactory {
    public final static String HEAD_ERROR="ERROR_HEAD"; 

    //connection model XML head
    public final static String HEAD_CONNECTION="Connection";
    //public final static String HEAD_FOUND=HEAD_CONNECTION+"FoundModel";
    public final static String HEAD_CONNECTIONFROM=HEAD_CONNECTION+"From";
    public final static String HEAD_CONNECTIONTO=HEAD_CONNECTION+"To";

    //port model XML head
    public final static String HEAD_PORT="Port";
    public final static String HEAD_PORTOPERATION=HEAD_PORT+"OperationModel";
    public final static String HEAD_PORTGUIDE =HEAD_PORT+"GuideModel";

    public static String getModelXMLHead(ElementModel model){

         if(model instanceof ConnectionElementModel)
            return getConnectioModelXMLHead(model);
         else if(model instanceof PortElementModel)
            return getPortModelXMLHead(model);
         return HEAD_ERROR;
    }

    public static String getConnectioModelXMLHead(ElementModel model){

         /*if(model instanceof FoundModel){
                    return HEAD_FOUND;
         }
         else */if(model instanceof MessageFromModel){
                    return HEAD_CONNECTIONFROM;
         }
         else if(model instanceof MessageToModel){
                    return HEAD_CONNECTIONTO;
         }
         return HEAD_ERROR;
         }

    public static String getPortModelXMLHead(ElementModel model){
        if(model instanceof PortOperationModel){
            return HEAD_PORTOPERATION;
        }
        else if(model instanceof PortGuideModel){
            return HEAD_PORTGUIDE;
        }
        return HEAD_ERROR;
    }

}

7.9 XmlHeadFactory，用来产生与模型对应的xmlhead