I am interested to create a drag-and-drop layout designer using only JavaScript, HTML and CSS. The designer will allow the user to drag the page elements from one place to another (something like Blogger's layout designer) to create a site layout. But I don't want to hand code everything in JavaScript, I would prefer to write my application in .NET (preferably) or Java and rely on a compiler to compile it to JavaScript and HTML.
What are the .NET or Java to JavaScript compilers that you have used and can recommend? For Java to JavaScript I know GWT is available. What about .NET to JavaScript? Microsoft did come out with Volta, but the project seems to be no longer available.
Look no further, you already mentioned GWT pick that!
It has a very good API and many good applications have use them.
Even JavaScript frameworks like http://extjs.com/ have GWT support.
I use it for an small JavaScript calendar recently.
To be honest, I don't really like JavaScript that much. Most of the times the errors are hard to track (specially for a non JavaScript guy as me) and the workarounds included some plug-ins for the explorer just to get exactly what a compiler should do. Catch silly error early.
In the other hand I'm very familiar with the Java Programming language, and many of the libraries (if not the most important) such as java.lang and java.util have been ported to GWT.
Plus, the guy who wrote relevant parts of java.util is the same behind GWT (google Joshua Bloch.)
Check out Nikhil Khotari's Script# project. It allows you to write C# code and compiles it to JavaScript.
Script# has already been mentioned. It hasn't been updated since August 2008.
Milescript is another, but also has seen very little for 6 months.
Extsharp for the Ext library. Adds Ext support for Script#
Javascript compiler to Java (going the wrong way for you)
Java to script Eclipse plugin
My issues with Script# (a known issue) is it doesn't support jQuery yet. However it comes with a very lightweight library to tie in with the .NET framework, in Nikhil's sscorlib.js file and ssfx.core.js files. And also has support for lots of other Javascript APIs (mostly Microsoft, seeing as he is in the ASP.NET team).
I'd love to see a Script# extension for jQuery (I'm thinking about writing it if it's easy enough). As it stands, most don't provide full compilation yet but they're certainly getting there.
Update: I wrote a small extension to enable JQuery support Script# a few months ago. The project can be found here.
I'm going to second the use of GWT. I've used it for several projects and, when used in combination with a modern editor like Eclipse or IDEA, it really makes the mess manageable.
It's important to note that not only does it allow you to write in Java and have that transformed into optimized and obfuscated Javascript it also comes with a substantial subset of the core Java API. In addition to this they provide lots of additional classes for doing things like parsing and working with JSON and XML and communicating with a server via asynchronous HTTP. You can check out the docs to get an idea of what else they offer.
Another feature that might be of special interest to you for implementing drag and drop functionality is it's integration with javascript libraries like Ext and scriptaculous. Either through pre-built interfaces or via JSNI
Also for Java there is J2S.
Java2Script (J2S) Pacemaker provides
an Eclipse Java to JavaScript compiler
plugin and an implementation of
JavaScript version of Eclipse Standard
Widget Toolkit (SWT) with other common
utilities, such as java.lang.* and
java.util.*. You can convert your
SWT-base Rich Client Platform (RCP)
into Rich Internet Application (RIA)
by Java2Script Pacemaker.
This means that if you use the SWT IDE (drag and drop) you can then convert the generated code to JS + HTML.
I wouldn't hand write any Javascript for UI. This can lead to maintenance disaster. jQuery is what I am using but I still wouldn't use it to write full UI Javascript code. ExtJS is also another good option if you plan to write in Javascript. In general what I am saying here is that it's so much easier to main in Java/C# than Javascript. Check out cappuccino framework and Atlas. Never used GWT. Script# is similar to GWT but for ASP.NET framework. Also depends on the requirement, if your site is public facing then RIA isn't a good option. It's all about which extreme end you pursuit (hand written and web standard, or RAD or libraries like jQuery/ExtJS as the middle option).
Check out Axial, a .NET to JavaScript converter that works well in ASP.NET. It supports WebForms, jQuery and canvas. It's not very mature, but it's worth a look.
http://jsc.sourceforge.net/ is a C# to JavaScript, Java, Flash and PHP compiler.
JscriptSuite offers another free .NET to Javascript compiler. There is a big difference to Saltarelle (jsc, SharpKit# etc.). Developer write down and debug only C# code (or any other .NET langauge), like in GWT. Javascript will be generated für deployment only.
Related
I want to create a mod for Minecraft, and I am aware it uses Java. I am currently learning JavaScript, and was wondering if I am able to use JavaScript for the SDK.
Yes and no.
Java is not Javascript...but a Java project can interpret Javascript
Java and Javascript are two completely different languages. However, there is a javascript interpreter created in Java, that you can plug in to java, called Rhino. However, although Rhino makes it easier to embed Javascript into your Java code, its not a simple drop in solution that would allow you to simply script what ever you want with out going through the effort of makin the proper connections. Definitely achievable, but you wont likely be able to start scripting without making that time investment to connect Java and Javascript.
Background story
The relationship between Javascript and Java is a rather shallow one. The similar name comes from a marketing plan back when it was being released by Netscape (which most developers ended up moving to the non-profit Mozilla). They made a deal with Sun (bought by Oracle) to share that similar name, but purely for marketing purposes.
Yes, it is possible to run JavaScript within a Java program, using the Rhino Javascript engine (for example).
However, this would not be a good way develop a Minecraft plugin / mod. None of your knowledge of the Javascript APIs would be relevant. Everything you did to interact with Minecraft would entail using Java classes and methods in the Java or Minecraft libraries.
My advice:
If your aim is to avoid learning Java ... don't be lazy. (You'll end up having to learn the Java APIs anyway. And learning another language will be good for you ... assuming you aspire to be a professional programmer.)
If your aim is to integrate some pre-existing Javascript code-base, it might work. But you might be better off porting the Javascript code to Java.
Sorry, Java and JavaScript are totally different languages. The "Java" in both of them was a marketing decision from ancient times.
They do share some of the same syntax that many languages share, however, so if you have learned JavaScript it might be a little easier to get started with Java. They are definitely NOT interchangeable, though.
Have a look at JDK1.6's ScriptEngine, the interface whose methods provide basic scripting functionality. Using these methods you can execute javascript. Numerous examples can be found on usage of this.
script support is avail from jdk 6 onwards:
reference link
However, this is not a full implementation of Rhino.
If I have implemented a Java Library (that offers certain functionality), could I transform this into a JavaScript library, such that the same functionality can be offered?
I know this may be an ask, but, I was wondering if there are frameworks existing that help in this?
No, in general this is not possible, Java and JavaScript are more or less completely different languages.
However there are a couple of Java to JavaScript translators that you can try. Java2Script is one such tool. Apparently the Google Web Toolkit (GWT) does this as well. Source.
While you could probably do some sort of conversion, it's important to note that Java and JavaScript, while similarly named, are not at all related. Unfortunately, I think you'll be hard pressed to find a framework or system that does a good job converting one to the other. :(
I'm working on a client-side Java application for which I want to create a web-based user interface (which will be served up to a browser from the local app). At the risk of oversimplifying, its a microblogging tool that will support functionality similar to Twitter and Facebook. Its open source, and you can read more on our wiki.
Its important that this app is extremely easy to use, and I also want it to look good relative to contemporary web applications (such as the examples available on the Chrome web store). Since I am not a web designer, I'm hoping to use tools that give me an attractive UI "out of the box". Oh, and I need to keep the distributable file reasonably small (un him so whatever I use needs to be reasonably lightweight.
So far, I've looked at Sproutcore and GWT.
Sproutcore apps definite have the appearance I'm hoping for, but I'm not that familiar with JavaScript, and after some experimentation is not entirely clear to me how I will achieve some of the more sophisticated functionality that I think I'm going to need.
Being Java, GWT is more within my comfort zone, however I had a hell of a time just getting my development environment set up properly. It seems that GWT wants to dictate the structure of my application, but since the user interface is only a small part of it I'm not willing to build the entire app around GWT.
Something else I've been thinking about is using CoffeeScript (which seems more palatable him and him him him him him than JavaScript, and there are Maven builders for it), perhaps together with JQuery-UI.
What other options should I consider?
To recommend two big javascript frameworks Sencha and Cappuccino.
These have an extensive UI toolkit out of the box. The latter has an MVC framework build in, the former has a general JavaScript library build in. Both come highly recommended.
Also as recommended jQuery UI is a reasonable toolkit. I would personally couple Sencha for its rich UI toolkit and a lightweight MVC framework like Backbone. I'm afraid this does require learning JavaScript well.
You can also instead drive your JavaScript UI toolkit mainly from the server and skip the clientside MVC. For that sencha should surfice as a UI toolkit, but if you want meaningful functionality you will need some more structure. I would also recommend RequireJS for modular file management.
Take a look on Vaadin its based on GWT but simpler to use. I use it since 2 years and i'am not a designer too.
Take a look at jQuery & jQuery UI (jQuery Modile if you are looking to deploy to hand held devices)
Also, since you mentioned that you are not a designer, you might want to implement the front end in an MVVM pattern to separate the UI from the business logic of your applications. Knockout is a nice way to do with with decelerative data binding
I don't like writing plain JavaScript, so I'll tell you little bit about Java based frameworks. Recently, I've picked Google Web Toolkit.
Pros:
plenty of materials
Eclipse + Google plugin
Very intuitive API
3rd party libraries
Fancy widgets + optimized JavaScript
lot of generics
very active community
awesome async callbacks
Cons:
very slow debugging, that will drive you mad sooner or later
lot of deprecated code for so young framework
Mixed feelings:
You don't have to write declarative UI (you can do Swing-like development), but your code grows bigger and less maintainable, so it is quite probable that you'll eventually learn some declarative UI like UI Binder
Visual designer for GWT is somehow nice, but very unstable (eclipse) :(
Some considerations:
Do some prototyping with Vaadin. Try some debugging. Then try GWT and debugging on similar sized project. Consider debugging as the VERY important decision factor, because GWT debugging was the most frustrating thing for me.
Consider JSF + some nice rich component framework for JSF like RichFaces, IceFaces, PrimeFaces etc (but you app won't be "light" and "small" anymore if you really care). Be sure to be perfectly comfortable with environment (IDE + plugins), nothing beats JSF there (I'd pick RichFaces + Seam today, if full Java EE is option).
If you don't want to learn javascript I recommend you GWT with Sencha-GWT (GXT), you can develop all your app in java language, and also debug your code in java.
It is very easy to create a web app with this technology, and provides almost all funcionality available in javascript version.
Also you can mix it with hibernate and giled to persist your data, and giled helps you to serialize hibernate objects.
I have been writing an application in SproutCore for the front-end and a Java backend. In my mind this works perfectly.
The backend can stop worrying about HTML and JavaScript contents on the client side, if the request is XHR or plain request/response. I can implement the backends using plain old Java Servlets, and only worry about the data that is passed between the client and the server (JSON for the most part).
The client becomed fast and responsive, and SproutCore has a rich amount of components that you can mix and match.
So in other words with SproutCore (and Cappuccino and other full-blows MVC JavaScript frameworks) you can let your client do what it does best : Render and display HTML, CSS and JavaScript, while leaving your server to worry about what it does best: retrieve, store and update data. If you are interested, the source code for this project is available with the GPLv3 licence: https://github.com/joachimhs/EurekaJ
I have written an article about the differnt approaches between server-side MVC and client-side MVC here: http://haagen.name/2011/05/24/The_RIA_MVC_Model.html.
Also SproutCore comes with the MIT licence, so its avaiable for use without (m)any restrictions.
I'd like to learn GWT, and I like the fact that it compiles to Javascript. My question is, how much of Java I can really use with GWT? My guess would be that limitations apply mostly for client side, while on the server side I should be able to make use of any existing Java library, right? Or, will I be only able to use a small subset , because of the compilation to Javascript thing?
What are it's limitations? I am interested in what it's not able to do, or things that require too many workarounds to implement. I need to know if learning GWT is a good choice for a possible freelance carrier in web development.
The GWT website has this documentation exactly to answer that question.
See the JRE emulation docs. Those are the supported out of the box emulated classes that you can use.
"Google Web Toolkit includes a library that emulates a subset of the Java runtime library. The list below shows the set of JRE packages, types and methods that GWT can translate automatically. Note that in some cases, only a subset of methods is supported for a given type."
You can also provide your own emulation for other classes using <super-source/> in your gwt.xml to point to a package that will provide replacement Java classes for those that can't be directly compiled to JavaScript.
I've been reading about Rhino as a useful way to implement JavaScript inside my Java code.
After reading for a while, searching in google and here, I couldn't find a real reason for which I would use JavaScript inside Java.
Could you point some real world advantages you find on using Rhino for a regular Java application?
Note that since Java 6, the scripting API is in the standard Java library - see the documentation of the package javax.script. The API in javax.script is an adapted version of Rhino. The scripting API supports not only JavaScript, but many other scripting languages.
See Java Scripting Programmer's Guide
The front page there mentions some reasons you might want to use scripting:
Application extension/customization: You can "externalize" parts of your application - like configuration scripts, business logic/rules and math expressions for financial applications.
"Command line" shells for applications -for debugging, runtime/deploy time configuration etc. Most applications have a web-based GUI configuaration tool these days. But sysadmins/deployers frequently prefer command line tools. Instead of inventing ad-hoc scripting language for that purpose, a "standard" scripting language can be used.
An example: You can script Oracle Weblogic using Python scripts, for example to configure your application server domain, to start or stop the server and to do other administration tasks.
Processing XML with Rhino and E4X is a joy compared to most of the Java XML APIs
You have existing JavaScript that "just works" and you don't want to re-write it. This can happen if you have some calculation or processing happening on the client side and move it to the server.
All kinds of neat caching and code loading tricks.
Your problem is better solved by a more dynamic language then Java.
List comprehensions ;)
The benefit of embedding a script language like javascript into your software is that you can offer others a way to write plugins for your software without giving the source code away.
A reason to write the whole app in another language is that you are able to write an app for a company which deploys it in their Java EE environment without having to learn Java.
We use JS (via Rhino) for a DSL in one of our products. It isn't a great DSL, but that is a fault of how we use JS, rather than Rhino.
If you considering to .Net also, I suggests to get along with Rhino.
Besides Java enviroments, rhino is one of the best performance interpreter on .NET environment (using IKVM). On the other hands, nashorn is very slow on .net.
Porting your own Rhino project to .NET is not so difficult.