org.eclipse.gmf.runtime.diagram.ui.editpolicies.CreationEditPolicy 中一个方法

 1 /**
 2      * Method getCreateElementAndViewCommand.
 3      * 
 4      * @param request
 5      * @return Command Which creates the sematnic and the view command for the
 6      *         given CreateViewAndElementRequest
 7      */
 8     protected Command getCreateElementAndViewCommand(CreateViewAndElementRequest request) {
 9         // get the element descriptor
10         CreateElementRequestAdapter requestAdapter =
11             request.getViewAndElementDescriptor().getCreateElementRequestAdapter();
12 
13         // get the semantic request
14         CreateElementRequest createElementRequest =
15             (CreateElementRequest) requestAdapter.getAdapter(
16                 CreateElementRequest.class);
17 
18         if (createElementRequest.getContainer() == null) {
19             // complete the semantic request by filling in the host's semantic
20             // element as the context
21             View view = (View)getHost().getModel();
22             EObject hostElement = ViewUtil.resolveSemanticElement(view);
23             
24             if (hostElement == null && view.getElement() == null) {
25                 hostElement = view;
26             }            
27 
28             // Returns null if host is unresolvable so that trying to create a
29             // new element in an unresolved shape will not be allowed.
30             if (hostElement == null) {
31                 return null;
32             }
33             createElementRequest.setContainer(hostElement);
34         }
35 
36         // get the create element command based on the elementdescriptor's
37         // request
38         Command createElementCommand =
39             getHost().getCommand(
40                 new EditCommandRequestWrapper(
41                     (CreateElementRequest)requestAdapter.getAdapter(
42                         CreateElementRequest.class), request.getExtendedData()));
43 
44         if (createElementCommand == null) 
45             return UnexecutableCommand.INSTANCE;
46 
47         // create the semantic create wrapper command
48         SemanticCreateCommand semanticCommand =
49             new SemanticCreateCommand(requestAdapter, createElementCommand);
50         Command viewCommand = getCreateCommand(request);
51 
52         Command refreshConnectionCommand =
53             getHost().getCommand(
54                 new RefreshConnectionsRequest(((List)request.getNewObject())));
55 
56 
57         // form the compound command and return
58         CompositeCommand cc = new CompositeCommand(semanticCommand.getLabel());
59         cc.compose(semanticCommand);
60         cc.compose(new CommandProxy(viewCommand));
61         if ( refreshConnectionCommand != null ) {
62             cc.compose(new CommandProxy(refreshConnectionCommand));
63         }
64 
65         return new ICommandProxy(cc);
66     }