JavaScript MVC. Once a bit player, JavaScript increasingly takes center stage. Its footprint—the space it takes up on our servers and in our development schedules—continues to grow. So how can we make our JavaScript more reusable and easier to maintain? Perhaps MVC will offer some clues. Article Continues Below While MVC is a familiar term to those in back-end application development—using frameworks such as Struts, Ruby on Rails, and CakePHP—MVC’s origin in user interface development lends itself to structuring client-side applications.
Let’s examine what MVC is, see how we can use it to rework an example project, and consider some existing MVC frameworks. What is MVC? The acronym has been mentioned six times already, and if you haven’t heard it before, you’re probably champing at the bit to find out what it stands for. Back in 1978 at Xeroc PARC, Trygve Reenskau recalled the origin of the MVC concept (PDF): There are four roles in this user interaction paradigm. In other words, a user does something. Trygve/MVC. Home themes mvc I spent a very happy and inspiring year as a visiting scientist with the Learning Research Gorup (LRG) at Xerox PARC from the summer og 1978 to the summer of 1979. This group was dedicated to Alan Kay's vision of the Dynabook; a portable computer that should contain all data of interest to its owner/user.
Very importantly, these data included the programs the owner used to manipulate them. The owner/user should be able to understand and write the programs, thus gaining ascendancy over the computer. The MVC notes should be read on this background. A note on DynaBook requirements 22 March 1979 (Partial scan, 11 pp I have sometimes been given more credit than is my due, so I should stress that I am not one of the original inventors of Smalltalk. Jim Althoff and others implemented a version of MVC for the Smalltalk-80 class library after I had left Xerox PARC; I was in not involved in this work. How does MVC work? When the user interacts with an application designed using the MVC principles, the Model, the View, and the Controller communicate together to give the user the ability to interact with the Model and perceive the expected results. There are many ways in which the Model, the View and the Controller can work together as explained by Trygve Reenskaug in his paper.
Here the Model reacts only to the Controller’s requests and View’s requests (if any). That is the Model would modify or retrieve data it represents only on the initiative of the Controller or the View. So upon the user’s request the controller would transmit the command to the Model and notify the View of a change in the Model’s state. The View could then request the changes to the Model or the Controller could trasmit those changes to the View. The Model is thus passive. As explained in Steve Burbeck 1992 paper on MVC and Smalltalk: Like this: Be the first to like this. The Smalltalk MVC paradigm with pluggable views. Tweak vs Morphic vs MVC Squeak Smalltalk. Model View Controller History. Model–view–controller. Model–view–controller (MVC) is a software pattern for implementing user interfaces.
It divides a given software application into three interconnected parts, so as to separate internal representations of information from the ways that information is presented to or accepted from the user.[1][2] The central component, the model, consists of application data, business rules, logic and functions. A view can be any output representation of information, such as a chart or a diagram. Multiple views of the same information are possible, such as a bar chart for management and a tabular view for accountants. The third part, the controller, accepts input and converts it to commands for the model or view.[3] Component interactions[edit] A typical collaboration of the MVC components In addition to dividing the application into three kinds of components, the Model–view–controller (MVC) design defines the interactions between them.[4] Use in web applications[edit] History[edit] See also[edit]
GWT, Spring MVC, and REST on Google App Engine / Java - Part 1. When googleing how to integrate GWT and Spring/Spring mvc, the most popular answer is to use the GWT- Widget/Server Library. The solutions are wrapping pojos as an RPC service or for better performance taking a spring controller and adding RPC functionality by extension. With the intoduction of REST features in Spring MVC 3.0, this should make integration between GWT and Spring more natural. This is how to get it all working together on Google App Engine / Java. First use Spring 3.0 M2. <dependency><groupId>org.springframework</groupId><artifactId>org.springframework.spring-library</artifactId><type>libd</type><version>3.0.0.M2</version></dependency> Add the milestone repositorySpringSource Enterprise Bundle Repository - External Bundle Mile ensure your using asm 2.2.3 Now in the web application you need to create the REST support with MVC.
In you spring configuration , it will look like this now.. return "greet"; }} Building a Proper MVC Pattern for the web. Search Google for “web application MVC patterns” or any variant thereof, and the vast majority of results will talk about the server side MVC. This traditional answer will tell you the browser sits outside the MVC altogether, and sends in HTTP requests that are handled by the Controller, then all the MVC garble happens, and finally the View spits out a brand new HTML page (or XML/JSON for AJAX) for the browser to consume. All this ends up looking something like: “So what’s the problem with this model?”
You ask? The JavaScript layer of course . All of the JavaScript in an app is completely unmanaged, and it ends up looking like spaghetti, orThe server side View tries to manage and encompass everything that happens in the browser – including JS – and the code still looks like spaghetti The “honest” version of the above diagram should really look more like this: Clearly this isn’t any way to design an app. What’s needed is to rethink web application architecture. Moving the ‘C’ in MVC. I’m sure I’m not the first to suggest this, but here goes. Ever since somebody first thought of applying the Model-View-Controller paradigm to the web, we’ve had this: The View is a conflation of HTML and JavaScript. JavaScript is an afterthought, a gimmick to make pages “dynamic.” All the real action is in the Controller, which talks to the database, processes the internal application logic, and renders templates before sending complete pages back to the client.
But what if we implement the Controller entirely in JavaScript? Now we can put the Controller on the client, and build a RESTful HTTP interface to communicate with the database. Obviously there are many issues to consider. There are some interesting possibilities. I’m always amazed when one of my posts show up on Reddit. Yes, in a sense I’ve described Ajax. I like Sun’s MVC diagram in which the View takes an active role in rendering the model rather than being just a template. Understanding Model-View-Controller. May 5, 2008 Like everything else in software engineering, it seems, the concept of Model-View-Controller was originally invented by Smalltalk programmers. More specifically, it was invented by one Smalltalk programmer, Trygve Reenskaug.
Trygve maintains a page that explains the history of MVC in his own words. He arrives at these definitions in a paper he published on December 10th, 1979: Models Models represent knowledge. A model could be a single object (rather uninteresting), or it could be some structure of objects. It may seem like we're deep in Architecture Astronaut territory now, but bear with me. This ubiquitous trifecta represents MVC almost perfectly. Model The HTML is the "skeleton" of bedrock content.
So if you believe the web has been at all successful -- most signs I've seen point to yes -- then you also have to acknowledge the incredible power of Model-View-Controller. Just take a gander at the project layout in a sample ASP.NET MVC project : Posted by Jeff Atwood Tim @zeroth: MVC. Home themes mvc I spent a very happy and inspiring year as a visiting scientist with the Learning Research Gorup (LRG) at Xerox PARC from the summer og 1978 to the summer of 1979. This group was dedicated to Alan Kay's vision of the Dynabook; a portable computer that should contain all data of interest to its owner/user.
Very importantly, these data included the programs the owner used to manipulate them. The owner/user should be able to understand and write the programs, thus gaining ascendancy over the computer. The MVC notes should be read on this background. The user was the czar; everything done at LRG was done to support him. An earlier paper adds some background for MVC: A note on DynaBook requirements 22 March 1979 (Partial scan, 11 pp I have sometimes been given more credit than is my due, so I should stress that I am not one of the original inventors of Smalltalk. The two papers have been copied together here:(PDF, 396 567 bytes)