Hibernate integration: CRUD operations

[bgranvea]

Hi,

I would like to load my Hibernate objets in an editable Grid or a Tree and send the changes (updates/deletion/insertion) back to the server. I'm not sure what is the best way to do this with GXT.

I've played a little bit with SmartGWT and they have a nice concept of Datasource which encapsulates the CRUD operations. You just have to implement a RPCDatasource and to give it to a grid.

I don't see the equivalent of this in GXT.

There is the RpcProxy but AFAIK it only handles loading of remote objects. I've seen that there is a StoreListener to be notified of the modifications in the local store and send them to the backend, is that the way to go?

Of course, I don't want to send directly my persistent objects. I've implemented all the necessary DTOs.

Thanks for your help.

[jackielii]

I have the same question.

[danielbertini]

Anyone can help?

[terciofilho]

The Grid itself is just a Render. You have to work directly inside a Store.

In your store you have a Loader, that is responsible to load the Store Data. This is easy, just implement a RpcProxy and you are done.

To work with modifications, like insert, update and delete, you must implement the way is more easy to you.

I'll explain my implementation

I have a object MyStore, that extends a ListStore<ModelData>. In this store I set a Loader(With a RpcProxy), so it can be loaded without any work.

To insert a record I have a Toolbar with a New Record button that call this method in MyStore:

	public ModelData createNewRecord()
	{
		final ModelData modelData = new ModelData();
		this.store.insert(modelData, 0);
		// I create a field(That I use as Primary Key) just to flag this modelData as Dirty, so I know it's a new one.
		final Record record = this.store.getRecord(modelData);
		record.beginEdit();
		record.set(RecordConstant.PRIMARY_KEY, null);
		record.endEdit();
		return modelData;
	}

This will create an empty ModelData, and will return it, so I can start editing by doing this(I use a Row Editor):

int modelIndex = this.store.indexOf(this.store.createNewRecord());
this.rowEditor.startEditing(modelIndex, false);

Well, this will start editing this new record.

To save the modified records I do this(I use the Command Pattern, so I wrap the action inside an Action object):

	public void saveModifiedRecords(final AsyncCallback<Integer> callback)
	{
		if (callback == null)
		{
			throw new IllegalArgumentException("callback cannot be null!");
		}

		final List<Action<?>> actions = new ArrayList<Action<?>>();

		// Create an SaveStoreAction for every modified Record
		final List<Record> modifiedRecords = this.store.getModifiedRecords();
		if (modifiedRecords.size() > 0)
		{
			for (final Record record : modifiedRecords)
			{
				final int documentId = this.document.getId();
				actions.add(new SaveStoreAction(documentId, this.parentModelData, (ModelData) record.getModel()));
			}

			// Create a Batch Action
			final BatchAction batchAction = new BatchAction(OnExceptionType.IGNORE, actions);

			this.actionService.executeAction(batchAction, new AsyncCallback<BatchResponse>()
			{
				public void onFailure(final Throwable caught)
				{
					// Action failed!
					callback.onFailure(caught);
				}

				public void onSuccess(final BatchResponse result)
				{
					int unsavedRecords = 0;
					for (int i = 0; i < result.getResponses().size(); i++)
					{
						final SaveStoreResponse saveResponse = (SaveStoreResponse) result.getResponses().get(i);
						final Exception saveException = result.getExceptions().get(i);
						// If no Exception, commit the modification
						if (saveException == null)
						{
							final Record record = modifiedRecords.get(i);
							record.commit(false);
						}
						else
						{
							unsavedRecords++;
						}
					}
					callback.onSuccess(unsavedRecords);
				}
			});
		}
		else
		{
			// No Modified Records to save!
		}
	}

This method when called, will create a Action object for every Modified Record in the Store, this Action is dispatched to the Server, that will update the Hibernate Objects based on the ModelData and will commit to Database, if an error occurs, the Action will return it to Client so the Client knows that that record has not been saved.

The deletion is basically the same, but you send the "this.grid.getSelectionModel().getSelectedItem();" to the Server.

Hope it helps.

[danielbertini]

Hello terciofilho!
Thank you for help!

[DaRkViDe]

Hi, when is called your save metod? Is it possible to call it on press event of the "Save" button of the row editor?
Or what event is fired whe the "Save" button of the row editor is pressed?
There are some example with a Save button on a toolbar on the bottom of the grid and use this to save data!
I don't wont to use another button like this but just the "Save" button of the row editor!
How can i catch with a listener the event of the "Save" button of the row editor like the following wrong example?

final RowEditor<RecapitiModel> re = new RowEditor<RecapitiModel>();
        re.setClicksToEdit(ClicksToEdit.TWO);
        re.addListener(Events.Submit, new Listener<BaseEvent>() {
            @Override
            public void handleEvent(BaseEvent be) {
            
        //call method to save modified data...
                
            }

There is any way to do it?
Please help, Thanks

[sven]

The RowEditor fires an Events.AfterEdit event editing.

[DaRkViDe]

thanks, i will try!

[DaRkViDe]

I have try this simple example but it doesn't works! It is correct? What is the problem?

  
 final RowEditor<RecapitiModel> re = new RowEditor<RecapitiModel>();
        re.setClicksToEdit(ClicksToEdit.TWO);
        
        re.addListener(Events.AfterEdit, new Listener<BaseEvent>() {

            @Override
            public void handleEvent(BaseEvent be) {
            
            Window.alert("hello");
                
            }
        });

Thanks

[DaRkViDe]

it works!