I am learning pureMVC and trying to implement the framework into one of my application. I have follwing case:
My main application has Canvas which is used to add different kind of custom components. One of the custom component is a "Search Component" (multiple instances are created on page). My search component has a textfiled and a search button and initiate search in following steps:
1-Clicking search button dispatches a custom event, that custom event keeps reference of search component as a property.
2-My AppMediator listens the custom event and get the reference of current search component along with search text.
3-Mediator send a notification (sentNotification(AppConstants.SEARCH_CLICKED, component)).
4-I have registered a command with SEARCH_CLICKED notification.
5-Command retrieve a WebserviceProxy and invokes its Search(text) method.
6-WebserviceProxy talks to remote webservice and uses asyncToken to get results.
My Questions is:
My Command has the reference to the custom search component when it start search but search webservice takes some time and get the result. How can i handle the results back to custom search component that initiated the search. Since i have multiple instances of search component. What is the best place to keep the reference of that component, should i add a variables in WebserviceProxy to keep that reference and hand the results over to it, or i have to create a Global Proxy to keep references of such components?
Thanks
I have been using PureMVC for some years and I like it!
I think you have not yet understood roles and collaboration of main components.
You should not have any dependencies between Commands and UI-elements. Your Mediator has to get the concrete value from your UI-component and send it through the Notification. In this case the Command and the Proxy will get only a text value and it is no matter, what is the source of it! Suppose you will change your UI after some time and you will have another components on the user side to determine the search value. In your case you would have to change the Proxy and the Command. It would be bad.
Proxy may not have any information about Commands and Mediators. It can only offer its functions to let another components interact with it AND it sends Notifications with new information after getting it without knowing who is interesting in it.
Read the description of the framework once more and write your questions.
I had some problems with understanding the stuff too, I see your problem.
Based on Anton's answer, i re-think and tried to separate dependencis. As a result, i tried to mediate each instance of Search Widget with "SearchMediator" separately by providing different ID to the constructor of Mediator. Now, when search widget intiates a new search, it's mediator invokes the Command, Command invokes a method of Proxy to do actual search and fetch results from DB and sends a Notification. SearchMediator takes care about that notification and hands over the results to appropriate UI.
Related
I am trying to create a custom activity for windows workflow that needs to get the name of the workflow file that uses it. Is there a way to achieve this?
One way I can think of is to write a tracking participant and add it to the workflows' extensions collection. Your tracker would simply remember the name of the initial activity that launches.
Then your custom activity can query the activity context for an instance of your tracker, and read the "initial" activity executed from it.
I'll give a code example when I'm back in my laptop later today.
Why(In what scenarios) do we need to integrate Spring Webflow with Spring MVC? Both these frameworks are used to create web-app and I do not see any point why we would integrate them. I would appreciate if someone could clarify me about it.
This is really late but I don't see a satisfactory answer to this question and would like to share an approach I had tried in a recent project which I feel is better than the spring web flow approach which is strictly tied down to spring views and unnecessarily adds to the already existing xml load . I created a SPA(Single Page Application) using angular js with Spring MVC. In angular js I did not use routers or state, rather I created a div within the controller like below
On the server side to capture all possible transitions from one frame(I am referring to a particular screen in the SPA) to another I created a tree of rules using MVEL . So in the database I had a structure which stored a tree of rules for every frame . The data in the MVEL expressions were being set by the various services each action invoked. Thus on any action the following steps were followed.
1) Validate the action.
2) Invoke various services.
3) Capture the data from these services and merge it with the existing data of the user.
4) Feed this captured data into collection of rules for each frame along with the details of the current frame.
5) Run the rules of the tree w.r.t to current frame and fetch its output.
6) If there is only one transition then that is the final transition. If there are 2 transitions and one is default then ignore the default transition and use the other transition.
7) Return the template name of the transition to the angular controller and set the value of the page variable in the scope of the controller.
Using this approach all my services had to do was store data in different data fields w.r.t a particular action. All the complex if-else conditions for Web Flows or any complex process definitions(like the one defined in Spring-Web Flow) were not required. The MVEL rule engine managed all that and since it was all in the database it could be changed without needing a server re-start.
I believe this generic approach with MVEL is a flexible approach which comprehensively handles the problem of a convoluted flow without making the application code a mess or adding additional unnecessary xml files.
We combine both. Web Flow for the multi-step activities, where it doesn't make sense to jump into the middle of a process, and plain-MVC Controllers for the single-step activities. Things you might bookmark individually.
For example, an appointment-scheduling application, "find my appointment" might be a single Controller that accepts identifying information. "Make a new appointment" is a flow, with multiple steps of selecting a location, date, time, confirm the appointment, etc.
If your application have complex Flow pages, events which need to be defined as Finite state machine then use Webflow. It would be justified to use webflow for website where you buy Insurance, Flight Tickets. Web Flow conditions are like:
There is a clear start and an end point.
The user must go through a set of screens in a specific order.
The changes are not finalized until the last step.
Once complete it shouldn't be possible to repeat a transaction accidentally
I am writing an Adobe AIR application using PureMVC.
Imagine that I have an page-based application view ( using ViewStack ), and user is navigating through this pages in some way ( like clicking the button or whatever ).
Now for example I have an Account Infromation page which when instantiated or showed again needs to load the data from WebService ( for example email, account balance and username ), and when the data is returned I want to show it on my Account Information page in the proper labels.
The problem is when I will execute this three Web Calls, each of them will return different resultEvent at different time. I am wondering what is the best way to get the information that ALL of the service calls returned results, so I know that I can finally show all the results at once ( and maybe before this happens play some loading screen ).
I really don't know much about PureMVC, but the as3commons-async library is great for managing async calls and should work just fine in any framework-setup
http://as3commons.org/as3-commons-async/
In your case, you could create 3 classes implementing IOperation or IAsyncCommand (depending on if you plan to execute the operations immediately or deferred) encapsulating your RPCs.
After that is done you simply create a new CompositeCommand and add the operations to its queue.
When all is done, CompositeCommand will fire an OperationEvent.COMPLETE
BTW, the library even includes some pre-implemented common Flex Operations, such as HTTPRequest, when you download the as3commons-asyc-flex package as well.
I would do it in this way:
Create a proxy for each of three information entities (EMailProxy, BalanceProxy, UsernameProxy);
Create a delegate class which handles the interaction with your WebService (something like "public class WSConnector implements IResponder{...}"), which is used by the proxies to call the end ws-methods;
Create a proxy which coordinates all the three results (CoordProxy);
Choose a mediator which will coordinate all the three calls (for example it could be done by your ApplicationMediator);
Create notification constants for all proxy results (GET_EMAIL_RESULT, GET_BALANCE_RESULT, GET_USERNAME_RESULT, COORD_RESULT);
Let the ApplicationMediator get all 4 notifications;
it is important that you should not only wait for all three results but also be ready for some errors and their interpretation. That is why a simple counter could be too weak.
The overall workflow could look like this:
The user initiates the process;
Some mediator gets an event from your GUI-component and sends a notification like DO_TRIPLECALL;
The ApplicationMediator catches this notification, drops the state of the CoordProxy and calls all 3 methods from your proxies (getEMail, getBalance, getUsername).
The responses are coming asynchronously. Each proxy gets its response from the delegate, changes its own data object and sends an appropriate notification.
The ApplicationMediator catches those notifications and changes the state of the CoordProxy. When all three responses are there (may be not all are successful) the CoordProxy sends a notification with the overall result.
I know it is not the best approach to do such an interaction through mediators. The initial idea was to use commands for all "business logic" decisions. But it can be too boring to create the bureaucracy.
I hope it can help you. I would be glad to know your solution and discuss it here.
I have a standard web page with Ajax update panel. WorkFlow of the page is : The user can add some entity, delete some entity(on click of their respective buttons) to create some definition. And then user can save these definition, edit it and delete it.
Upon adding/deleting the entities, a complex calculation needs to take place which would be time intensive. What I want is, when the user adds or deletes some entity, a separate thread should do the computation and update the UI. The point to be kept in mind here is, when the entity are added or deleted , the corresponding server side code need to be run first, which adds/deletes the entities from a collection stored in session(that means I can not launch a ajax call on the button, because the server side code for the button needs to run first), and then the logic for computation.
What I have thought of doing is
1. Make the server call for button click
2. When response returns, use AJAX client life cycle to catch the response before page is rendered. This is the place where I would make ajax call, if request was for add/delete entity.
This how ever seems over complicated. I am sure, there must be a easy way to do this.
Found out answer to my problem. What I needed was PageAsyncTask which is in built in asp.net for these kind of jobs.
Google
Until recently I have been using cairngorm as a framework for flex. However, in this latest project I have switched to Mate. It's` still confusing me a little as I kind of got used to leaving data in the model. I have a couple of components which rely on the same dataset(collection).
In the component the creation complete handler sends a 'GiveMeMyDataEvent' which is caught by one of the eventmaps. Now in cairngorm in my command class I would have had a quick peek in the model to decide whether I need to get the data from the server or not and then either returned the data from the model or called the db.
How would I do this in Mate? Or is there a better way to go about this, I'm trying to utilize the data that has already been recieved from the server, but at the same time I'm not sure I have loaded the data or not. If a component which uses that same data has been instantiated then the answer is yes otherwise no.
Any help/hints greatly appreciated.
Most things in Mate are indirect. You have managers that manage your data, and you set up injectors (which are bindings) between the managers and your views. The injectors make sure your views are synchronized with your managers. That way the views always have the latest data. Views don't get updated as a direct consequence of dispatching an event, but as an indirect consequence.
When you want to load new data you dispatch an event which is caught by an event map, which in turn calls some service, which loads data and returns it to the event map, and the event map sticks it into the appropriate manager.
When the manager gets updated the injectors make sure that the views are updated.
By using injectors you are guaranteed to always have the latest data in your views, so if the views have data the data is loaded -- unless you need to update periodically, in which case it's up to you to determine if data is stale and dispatch an event that triggers a service call, which triggers an update, which triggers the injectors to push the new data into the views again, and round it goes.
So, in short the answer to your question is that you need to make sure you use injectors properly. If this is a too high-level answer for you I know you can get more help in the Mate forums.
I ran into a similiar situation with the app I am working on at the moment, and found that it is easily implemented in Mate when you start thinking about having two events.
The first event being something like DataEvent.REFRESH_MY_DATA. This event is handled by some DataManager, which can decide to either ignore it (since data is already present in the client and considered up to date), or the manager can dispatch an event like DataEvent.FETCH_MY_DATA.
The FETCH_MY_DATA event triggers a service call in the event map, which updates a value in the manager. This update is property-injected into the view, happy days :)