Two Java programs have to communicate with each other, To do that I found two possibilities
Using Sockets
Using JavaSpaces
After looking into the description, I found out, that JavaSpaces is apparently the better solution. Sadly, I can't get it to run. Ever totourial roots me to another installation process, to other files and so on.... :(
How to install JavaSpaces, where to download them etc?
If someone offers me a better solution for it I'll be thankful to (JavaSpaces seems to be from 2005)
this are the websites I found so far:
http://www.jroller.com/matsh/entry/intreagued_by_javaspaces_try_blitz
(Installation description, not working...)
http://www.jini.org/wiki/Main_Page
(Download links are broken)
http://www.jarvana.com/jarvana/inspect/com/sun/jini/jini-starterkit/2.1/jini-starterkit-2.1.zip?folder=jini2_1/
(Download of jini starter kit)
For one quick start using GigaSpaces, a commercial JavaSpaces product (with a community edition available), see http://www.gigaspaces.com/wiki/display/XAP8/Data+Grid+Quick+Start
Also see http://replay.waybackmachine.org/20070202031207/http://www.theserverside.com/tt/articles/article.tss%3Fl%3DUsingJavaSpaces and http://www.theserverside.com/news/thread.tss?thread_id=42164 and http://www.enigmastation.com/?page_id=425
JavaSpaces is great, IMO (I'm biased, as I work for GigaSpaces... but then again, I work for GigaSpaces because I think the underlying technology is great.) - it's got a very simple API but the transaction model is actually pretty strong, and it's very fast. It's simpler and stronger than JMS, and has a simpler deployment/connection model.
If you're GigaSpaces-averse for some reason ("yikes, someone makes money from this") you can look into Blitz as well.
In Feb 2009 another user on SO mentioned, that GigaSpaces is a mature version of JavaSpaces.
Looking at that older question, I start believing that JavaSpaces is dead..!?
Have you considered also using something like RMI where it becomes transparent the fact that you are invoking a method on a remote system?
Or JMS where you just send and read messages -- and the infrastructure routes them to the right place/process?
Or how about another approach where you have a network cache (e.g. memcached) where both processes can put and get items to/from the cache -- thus allowing for inter-process communication to a certain extent?
Related
Recently I got introduced to node.js and cool packages like express and jade. I have few questions consistently knocking my door:
If I pick node.js to build my next website, I will be using JavaScript to write my server-side complicated logic? but I don't think you can compare JavaScript with Java or Python to write server-side code as they have such a vast ocean of libraries. Is node.js really meant for it? or I have missed something?
Can I call Java or Python from node.js?
Not quite sure what most of these folks are talking about.
A "vast ocean of libraries" is something the community is actively working on. Check this: http://search.npmjs.org/#/_analytics -- there were 8 packages published yesterday
Its not going to solve your software design for you. As for where and how to write business logic, many of us embrace mvc or mvvm or something close to it. If you're building an application and like how Rubyists (for example), structure their code you might look at doing something just like that -- aint nobody going to tell you how to structure your code.
Check https://github.com/joyent/node/wiki/modules
Some of the more popular libraries for doing the day to day:
Express: http://expressjs.com/ - https://github.com/visionmedia/express
Sinatra inspired, use it to build a typical web app
Stats: 3407 watchers, 286 forks, on pull request 778
Compare that to Sinatra itself! 2529 watchers, 366 forks
With connect, it supports all kinds of middleware:
sessions,
all kinds of routing,
static files
some 15 different templating engines
validation, form handling, etc, etc
Socket.io: http://socket.io/ - make it 'real-time'
DNode: https://github.com/substack/dnode - do rpc between anything
Backbone.js: http://documentcloud.github.com/backbone/ - MVC
Variety of techniques for re-using your models on the server:
http://andyet.net/blog/2011/feb/15/re-using-backbonejs-models-on-the-server-with-node/
Spine.js: http://maccman.github.com/spine.tutorials/index.html - MCV
Techniques for re-using code on the server:
http://maccman.github.com/spine.tutorials/node.html
caolan/async: https://github.com/caolan/async - Help manage your async business logic
Database, pick your poision
node_redis, https://github.com/mranney/node_redis - or one of the eight other clients
"This is a complete Redis client for node.js. It supports all Redis commands"
node-mysql, https://github.com/felixge/node-mysql - or one of eleven other clients/orms
node-mongodb-native, https://github.com/christkv/node-mongodb-native
node-postgres, https://github.com/brianc/node-postgres
There's also a host of ORMs out there, if thats your bag. Things like http://mongoosejs.com/, http://sequelizejs.com/ and friends
Test-driven development is at the core of node. There are 15 different TDD packages to choose from that range from full code coverage analysis to custom assert modules.
Saying all modules are incomplete is silly. There is an incredibly dedicated group of people building and maintaining tons working open-source in this community every day.
There might be reasons to pass over node, but its not for an inactive community or lack of libraries.
I would say you missed something - more specifically, the core purpose of Node.js, that is, the asynchronous I/O model.
I started a little pet project to test Node.js - how it "feels" and how to program on it. I became impressed by the ease of working in such ecosystem: Node.js code is easy to write (although its asynchronous paradigm is not that straightforward for the conventional programmer), libraries are easy to build etc. etc. Even npm is amazingly easy: I just found the most straightforward way to provide code of your own as a library is to make a public package of it - and it is absurdly easy!
However, there is not much good tools to work with Node.js. Maybe because it is too easy to do anything, most libraries are partially-implemented, undocumented solutions.
Also, note that the relevant difference of Node.js is not the JavaScript language, but the asynchronous I/O model. It is the most interesting aspect of Node.js, but the asynchronous programming style is not as well tested as the conventional way of web development. Maybe it is really the marvel that is propagandized - or perhaps, it is not as good as promised.
Even in the case it pays off, will you have enough developers to maintain such an (at least still) unusual codebase? If you can get a lot of advantages from the asynchronous "way of life" of Node.js, you can use more consolidated languages and frameworks, such as Twisted for Python (which is my preferred languabe, so take care with my opinion :) ). There may be something like this for Java, too. Anyway, I suspect that you do not have a lot of interest in this model for now, since your question focuses more on languages than in the programming paradigm, so Node.js does not have much to offer to you anyway.
So... no, I would not develop something professonaly in Node.js for now, although I think it is both fun and instructive to study. You can do it, however - just do not do it without having in mind the main purpose of Node.js: asynchronous-IO, event-driven programming. If it is what you want, Node.js is a good alternative.
Ryan did not start with JavaScript. A large part of why Node was created in JavaScript is that JavaScript lacked vast oceans of libraries.
Those vast oceans of libraries are almost all written in blocking code.
To take full advantage of Node.js you need to limit your self to non blocking libraries. Which means that might need to write some libraries to complete your project in Node.js.
I think you'll be surprised by the amount of work you can get done in JavaScript via Node.js. There are a bunch of libraries available for Node and more are being written all the time. Furthermore, native extensions are also available for those times where you might need to drop down to a lower-level.
If you think there's a gap where Node won't be able to provide for your business logic, take a look around NPM or give Google a quick serch to see if anyone else has already solved your problem.
Of course, you can use Python, PHP, c++ or other technologies with nodejs 'cuz node can run it as a child process. Nodejs give you the freedom to use any technology which you want inside itself. You can use whatever you want combining the most performance programs.
There are some things that JavaScript just can't do. If you come up against those Node might not be the best choice for your app. However you can probably accomplish most of what you need.
As far as the API being limited, I suggest you take a look at npm and all the libraries in its repository. Specifically ones like underscore.js. Many aim to fill in the gaps of what native JavaScript lacks compared to other languages.
We are currently using MICO to establish the communication between a server and a client, where the client is a simulator written in C++ and the server is a java program displaying an animation of what happens in the simulation. It seems that the developemt of MICO has slowed down to an almost halt and bugs that only allow us to hack around them (as we don't have the time to first figure out which parts of MICO are responsible for codegeneration and so on) keep us from making real progress.
So, does any one of you know of a good drop-in replacement? We would like to have the following:
The compiler can generate both C++ and Java-Code from the idl.
The project should still show considerable support.
The implementation should be open-sourced (GPL or BSD, or something alike), as we use our programs to teach students as well.
The migration from MICO should be as easy as possible. (This is not a hard requirement, but would be a good thing)
I found some other CORBA implementations, e.g. TAO, but I didn't find any of which I could
say that they are still supported. Correct me if I am wrong here.
The Free CORBA® Downloads page might be of interest to you.
Just naming:
orbit2 1, also pyorbit etc.
omniORB
TAO (has already been mentioned)
1 On my Ubuntu box, apt-rdepends -r liborbit2 returns 5530 lines...
I don't know where CORBA or MICO in particular has gone in the last 5 years, but back then a drop in replacement was not really possible, since differences between vendors where still there.
Not necessarily API differences (POA, etc.) but
in implementation behavior,
in custom extensions which were required to make it work in a real-world environment (threading, load balancing, security, etc.),
in how the development tools worked
and also about the whole deployment or runtime story.
We had Orbix ASP/2000/Whatever and ORBacus which were interchangeable having a small compatibility layer, some Makefile framework to hide differences in tools (e.g. the IDL compiler) and some scripts for wrapping ORB specific processes.
Unfortunately, ORBacus has long been bought by (then) IONA, which already make Orbix. IONA itself has been bought by someone else (I forgot). The original authors of ORBacus, plus some devs from IONA Orbix, changed their ways somewhat and produced Ice, which is not CORBA but somewhat alike - of course without the glitches ;-)
Concerning TOA, I think it would be the "best" choice concerning still being developed as it is driven by research on the Washington University. But last time I looked, they didn't have Java implementation but people seemed to use JacORB.
Maybe all this helps you little, unless it brings even more confusion :-)
TAO as C++ ORB is still actively supported and developed (see http://www.cs.wustl.edu/~schmidt/commercial-support.html). For Java I would propose JacORB.
On http://www.orbzone.org there is an overview of available corba implementations.
I am looking for something that will make it easy to run (correctly coded) embarrassingly parallel JVM code on a cluster (so that I can use Clojure + Incanter).
I have used Parallel Python in the past to do this. We have a new PBS cluster and our admin will soon set up IPython nodes that use PBS as the backend. Both of these systems make it almost a no-brainer to run certain types of code in a cluster.
I made the mistake of using Hadoop in the past (Hadoop is just not suited to the kind of data that I use) - the latency made even small runs execute for 1-2 minutes.
Is JPPF or Gridgain better for what I need? Does anyone here have any experience with either? Is there anything else you can recommend?
Check out cascalog - http://github.com/nathanmarz/cascalog
Clojure is reported to work on Terracotta, subject to some patching.
Look at Skandium
Edit :
Above link is no more live, so adding github link
https://github.com/mleyton/Skandium
I suggest you look at Skandium, alternative licenses to GPL can be negotiated with the developers upon request.
Does anybody have experience using the open source offering from Terracotta as opposed to their enterprise offering? Specifically, I'm interested if it is worth the effort to use terracotta without the enterprise tools to manage your cluster?
Over-simplified usage summary: we're a small startup with limited budget that needs to process millions of records and scale for hundreds-of-thousands of page views per day.
I am in a process of integrating Terracotta with my project (a sensor node network simulator). About three weeks ago I found out about Terracotta from one of my colleagues. And now my application takes advantage of grid computing using Terracotta. Below I summarized some essential points of my experience with Terracotta.
The Terracotta site contains pretty detailed documentation. This article probably a good starting point for a developer Concept and Architecture Guide
When you are stuck with a problem and found no answer in the documentation, the Terracotta community forum is a good place to ask questions. It seems that Terracotta developers check it on a regular basis and pretty responsive.
Even though Terracotta is running under JVM and it is advertised that it is only a matter of configuration to make you application running in a cluster, you should be ready that it may require to introduce some serious changes in you application to make it perform reasonably well. E.g. I had to completely rewrite synchronization logic of my application.
Good integration with Eclipse.
Admin Console is a great tool and it helped me a lot in tweaking my application to perform decently under Terracotta. It collects all performance metrics from servers and clients you can only think of. It certainly has some GUI related issues, but who does not :-)
Prefer standard Java Synchronization primitives (synchronized/wait/notify) over java.util.concurrent.* citizens. I found that standard primitives provide higher flexibility (can be configured to be a read or write cluster lock or even not-a-lock at all), easier to track in the Admin Console (you see the class name of the object being locked rather then e.g. some ReentrantLock).
Hope that helps.
At the moment, the Terracotta enterprise tools provide only a few features beyond the open source version around things like visualization and management (like the ability to kick a client out of the cluster). That will continue to diverge and the enterprise tools are likely to boast more operator-level functionality around things like managing and monitoring, but you can certainly manage and tune an app even with the open source tools.
The enterprise license also gives you things like support, indemnification, etc which may or may not be as important to you as the tooling.
I would urge you to try it for yourself. If you'd like to see an example of a real app using Terracotta, you should check out this reference web app that was just released:
The Examinator
You may want to take a look at JBossCache/PojoCache which is an in-memory distributed caching solution. The difference is it uses a simple API to propagate objects across your 'cluster' of caches, where as Terracotta works at the classloading/jvm level.
(They don't actually have their own JVM, but they modify classes as they are loaded to allow them to be 'clusterable')
Our company had a lot of luck with JBossCache, I'd recommend checking it out.
Update
What I see in the OP message is "well, I don't really know what we need (thus the lack of detailed requirements), but may be some enterprizey tool will magically solve all our problems, known and unforeseen? That would be awesome!"
With an architectural approach like this it's not gonna fly. No success stories from Teracotta would change that.
OSS is beneficial when the community around it can replace the commercial support. Suppose the guy have a problem in production. Community cannot help -- it's too small for the obscure product like this. Servers are down, business is in danger. You see? You need a commercial license up-front. No money? Well, then you're not a business, and probably not gonna become one (if nobody's willing to invest into it).
Sorry for interrupting your day-dreaming.
IMHO:
Terracotta is a clustering solution. Clustering is required for large, enterprise-grade applications. Large applications mean big budgets. Big budgets mean you can afford commercial license from Terracotta.
To put it in another way: if you don't have budget to buy it, it's probably not beneficial for your project.
Everyone I talk to who knows (knew) about it claims it was the greatest thing since sliced bread. Why did it fail? Or, if it didn't fail, who's using it now?
Check out GigaSpaces. It's a quite successful Jini/Javaspaces implementation.
I think Jini has a great model, but it is stuck with Java. Web-services is more appealing because it works with standarized protocols, even though Jini service discovery is more natural.
Things have definitely quited down for the idea. Which is strange since you'd think its goals are even more relevant now.
http://www.jini.org/wiki/Category:News
old question, but JINI was given to Apache and became Apache River project. However, that project is now retired.
Zeroconf and other discovery protocols are similarly referred to as the greatest thing since sliced bread; it's just that the flavor keeps changing.
My two cents... Jini was/is nice, but I think it tried to be a Java-centric CORBA back in the day when corporations were beginning to be reluctant regarding paying the big bucks for what CORBA brought to the table. WS-* specs began to acquire the "accepted-solution" mind-share in the industry. I think there was a small window where Jini could have grabbed substantial market share, but it never happened. Sun wanted too much money for what Jini brought to the table compared to other alternatives. I would love to hear from folks that disagree! My opinion is that Jini is sound tech, but business-wise has no future in the enterprise. It may find a niche elsewhere, depending on what Oracle decides to do with it.
Jini was an amazing technology. The only reason pushed EJB systems was that it allowed Sun to sell more hardware as EJB ran best on highpowered machines (due to shared state and database access). At the time (1999) Jini allowed much better scalability which ran well on commodity hardware, so it made sense for Sun to not promote Jini. Its a shame as I kept wondering when someone would release an Open Source easy to use Jini server like JBoss did with J2EE. I did however save companies alot of time and money by using the Jini techniques (based on Linda TupleSpaces) and applying them to writing software systems by using Tuple Spaces implemented in other ways.
The jewel in the crown of Jini was it's JavaSpaces service IMO. Sad that Sun seem to have abandoned it. It still exists as Apache River, but is now retired.