In this article we try using\u00a0JArchitect<\/a>\u00a0to discover the PureMVC in depth, and talk about the main difference between it and the other variants.<\/p>\n PureMVC was popularized first by Flex and Flash developers, but it was ported after to many other languages. The following\u00a0GWT sample<\/a>\u00a0use the java PureMVC framework, let\u2019s analyze it to explore the PureMVC concepts. Here\u2019s the structure of the project<\/p>\n This structure shows the main PureMVC concepts:<\/p>\n The PureMVC best practices encourage developers to put each actor into a specific package, to modularize better the application.<\/p>\n The matrix gives us more details about dependency weight between all namespaces.<\/p>\n There\u2019s no dependency cycle, it\u2019s well layered what makes it very clear and simple to understand.<\/p>\n The PureMVC glue<\/span><\/p>\n To go deep inside the sample let\u2019s discover the dependency graph between all classes<\/p>\n What\u2019s interesting in this dependency graph, is that almost all classes uses INotification.<\/p>\n PureMVC use the publish-subscribe pattern to communicate between all actors(Model,View,Controler), and for this reason INotification is mainly used, and to check that let\u2019s discover the most popular types, for that we can use the TypeRank metric.<\/p>\n The three most popular types concern notification mechanism, what\u2019s proof that this concept is the glue of the PureMVC framework, almost all communication between actors use notification, that make them less coupled.<\/p>\n Publish\u2013subscribe is a messaging pattern where senders of messages, called publishers, do not program the messages to be sent directly to specific receivers, called subscribers. Published messages are characterized into classes, without knowledge of what, if any, subscribers there may be. Subscribers express interest in one or more classes, and only receives messages that are of interest, without knowledge of what, if any, publishers there are.<\/p>\n This allows asynchronous, event-driven communications between the actors of the system, and also promotes a loose coupling between those actors, since the subscriber never needs to have direct knowledge of the publisher.<\/p>\n For our sample we can search for all classes using Notifier class to notify the other actors.<\/p>\n Almost all actors: Mediators, Commands and proxies use the notification mechanism to communicate with each others.<\/p>\n Here\u2019s a concrete example of adding a new user from view.<\/p>\n In this sample the mediator ask the proxy to add a user and after send a notification to inform all the other components that a user was added.<\/p>\n What\u2019s interesting to note here is the fact that the mediator communicate directly with the proxy, in PureMVC, proxies can\u2019t act as subscribers, and can only publish notification.<\/p>\n Inside PureMVC Concepts<\/span><\/p>\n Facade<\/span><\/p>\n \u2013 Facade is singleton Only one static method getInstance instantiate it, this method has one parameter, so we can create many facades, each component has its own singleton facade identified by a name, and it\u2019s why we talk about PureMVC MultiCore.<\/p>\n \u2013 Facade Initialization:<\/p>\n The facade initializes all the other actors.<\/p>\n \u2013 Facade and notification:<\/p>\n The facade caches all actors, and when a notification is published, the facade notifies all observers.<\/p>\n Commands<\/span><\/p>\n Let\u2019s search for all methods used by DeleteUserCommand, the command responsible of deleting a user.<\/p>\n The command doesn\u2019t communicate directly with other components, except for the proxy as we observed before.<\/p>\n Mediators<\/span><\/p>\n
\n<\/span>
\nPureMVC basic Concepts<\/span><\/p>\n![\"\"](\"https:\/\/javadepend.files.wordpress.com\/2011\/11\/structure.png?w=595\" "\\"structure\\"")
<\/a><\/p>\n\n
![\"\"](\"https:\/\/javadepend.files.wordpress.com\/2011\/11\/matrix2.png?w=595\" "\\"matrix\\"")
<\/a><\/p>\n![\"\"](\"https:\/\/javadepend.files.wordpress.com\/2011\/12\/notif.png?w=595\" "\\"notif\\"")
<\/a><\/p>\nSELECT TOP 100 TYPES ORDER BY TypeRank DESC, TypeCa DESC\r\n<\/pre>\n
![\"\"](\"https:\/\/javadepend.files.wordpress.com\/2011\/12\/typerank2.png?w=595\" "\\"typerank\\"")
<\/a><\/p>\nSELECT METHODS FROM JARS \"PureMVC\" WHERE \r\nIsDirectlyUsing \"org.puremvc.java.multicore.patterns.observer.Notifier<\/span>\"\r\n<\/pre>\n![\"\"](\"https:\/\/javadepend.files.wordpress.com\/2011\/12\/notifused1.png?w=595\" "\\"notifused\\"")
<\/a><\/p>\n![\"\"](\"https:\/\/javadepend.files.wordpress.com\/2011\/12\/notification21.png?w=595\" "\\"notification2\\"")
<\/a><\/p>\n
\nIf we search where the facade is instantiated<\/p>\nSELECT METHODS WHERE \r\nDepthOfCreateA \"org.puremvc.java.multicore.patterns.facade.Facade<\/span>\" == 1<\/pre>\n![\"\"](\"https:\/\/javadepend.files.wordpress.com\/2011\/12\/facade2.png?w=595\" "\\"facade\\"")
<\/a><\/p>\nSELECT METHODS WHERE \r\nIsDirectlyUsedBy \"org.puremvc.java.multicore.patterns.facade.Facade<\/span>\"<\/pre>\n![\"\"](\"https:\/\/javadepend.files.wordpress.com\/2011\/12\/facadeinitialize.png?w=595\" "\\"facadeinitialize\\"")
<\/a><\/p>\n![\"\"](\"https:\/\/javadepend.files.wordpress.com\/2011\/11\/notification31.png?w=595\" "\\"notification3\\"")
<\/a><\/p>\nSELECT METHODS WHERE \r\nIsDirectlyUsedBy \"org.puremvc.java.multicore.demos.gwt.employeeadmin.controller.DeleteUserCommand<\/span>\"<\/pre>\n![\"\"](\"https:\/\/javadepend.files.wordpress.com\/2011\/12\/command.png?w=595\" "\\"command\\"")
<\/a><\/p>\nSELECT METHODS WHERE \r\nIsDirectlyUsedBy \"org.puremvc.java.multicore.demos.gwt.employeeadmin.view.UserFormMediator<\/span>\"<\/pre>\n
![\"\"](\"https:\/\/javadepend.files.wordpress.com\/2011\/12\/mediator1.png?w=595\" "\\"mediator\\"")
<\/a><\/p>\n![\"\"](\"https:\/\/javadepend.files.wordpress.com\/2011\/12\/model.png?w=595\" "\\"model\\"")
<\/a><\/p>\n