Application servers like Weblogic and WebSphere are all used like middleware. What is the difference between these two concepts?
Middleware is anything that is not part of an operating system, and neither is it part of one software application, but rather lies between them.
Hence, Application Server is a type of Middleware.
Middleware is more general than Application Server.
An application server is one type of middleware.
The fact is that the term middleware, when applied to distributed computing is rather vague and can be applied to any piece of software that exists between the server and client.
Application Servers may also include components like Web/Servlet containers. Middleware is something that enables inter-system communication/data exchange.
As far as my understanding
Application Server - Middlewares + your application
Middlewares - It acts as a bridge between your request and
application. They process the requests and provides response in
an efficient way.
To make more clear, WebSphere is an application server written in Java and a middleware can be injected into it to make your request and response efficient. Your request communicates with the middleware first and then to the application in the server.
correct me if I am wrong
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I know typically a process is either a service provider or client over D-Bus, is it practically possible that a process be both a service and client (I think it's okay)? I have such needs in my project, originally there is a service provider and client, some requirements come in, I need the original client to provide service as well. Is there any downside if it's theoretically doable?
Yes, it’s possible, straightforward to do, and there are no downsides as long as it’s a suitable architecture for the problem you’re trying to solve.
Many system services already do just this: they expose a system service on the bus, and also act as a client with other system services which provide information to them.
I am building a JavaFX client application communicating with Spring MVC Restful server(Spring boot 1.4.1) application which works as expected.
Some features require fast interaction with the server to validate limits and availability before proceeding to next input example check if member number insert is valid and if has exceeded limit to insert, during accumulation of records(each confirmed record temporarily stored in a tableview before sent to server for storage) before the records are actually saved.
Within JavaFX and Spring framework(in both frontend and backend) scope, how can such kind of features made look more interactive(or live) than normal "let-me-wait-for-response" approach
If question is not clear, just ask, otherwise i think it is
It appears that the only interaction you have between client (JavaFX) and server (SpringBoot) is through a REST API. This will make short bursts of data (such a validation) take longer.
Switching to another communication mechanism (for example gRPC or Netty with Msgpack) could help. Note that once you open the door for non-REST calls it'll make you re-think the use of REST in the first place.
Non-REST communication may not be an option depending on your requirements (firewalls, etc) or may need additional setup in order to surmount other obstacles, in other words, there's no free lunch.
I have a RESTful web-service application that I developed using the Netbeans IDE. The application uses MySQL server as its back end server. What I am wondering now is how often a client application that uses my RESTful application would refresh to reflect the data change in the server.
Are there any default pull intervals that clients get from the RESTful application? Does the framework(JAX-RS) do something about it Or is that my business to take care of.
Thanks in advance
#Abraham
There are no such rules. Only thing you can use for properly implementing this is HTTP's caching capabilities. Service must include control information how long representation of a particular resource can be cached, revalidated, never cached etc...
On client application side of things each client may decide it's own path how it will keep itself in sync with a service. It can be done by locally storing data and serve end user from local cache etc... Service can not(and shouldn't know) how clients are implemented, only thing service can do is to include caching information in response messages as i already mentioned above.
It is your responsibility to schedule the service to execute again and again. We can set time out interval but there is no pull interval.
I have a project that is currently in production delivering some web-services using the REST approach. Right now, I need to delivery some of this web-services in SOAP too (it means that I will need to deliver some of the same web-services in SOAP and others a bit different), so, I ask you:
Should I incorporate to the existent project the SOAP stack (libraries, configuration files, ...), building another layer that deliver the data in envelopes way (some people call it "anti-corruption layer") ?
Should I build another project using just the canonical model in common (become it in a shared-library) ?
... Or how do you proceed in similar situations ?
Please, consider our ideal target a SOA architecture.
Thanks.
In our projects we have a facade layer which exposes the services and maps to business entities, and a business layer where the business logic is run.
So to add a SOAP end point for an existing service, we just create a new facade and call in to the same business logic.
In many cases it is even simpler, since we use WCF we can have a http SOAP endpoint for external clients, and a binary tcpip endpoint for internal clients. The new endpoint can be added by changing the configuration without any need to change the code.
The way I think about an SOA system, you have messages and pub/sub. The message is the interface. Getting those messages into and out of the system is an implementation detail. I create an endpoint that accepts a raw message document (more REST-like, but not really REST) as well as an endpoint that accepts the message as a single parameter to a SOAP call. The code that processes the incoming message is a separate concern from the HTTP endpoint enablement.
You can use an ESB for this. Where ESB receive the soap messages and send the rest request to the back end. WSO2 ESB provides this functionality. Please look at this sample[1].
[1] http://wso2.org/project/esb/java/4.0.0/docs/samples/proxy_samples.html#Sample152
I have a question about the design of an application I'm working on.
I made a monolithic java application with sockets open 24/7, something like a game server. I'm just trying to say it's a single jar application instead of a modular servlet/page based web application.
I would now like to add a RESTful API to this application. So people/clients can make HTTP requests to my application to obtain certain info. Because of the monolithic nature of my java application I'm unsure of how to implement this. One other important thing: I'm expecting multiple requests per second, so it would be nice if I could have an existing http server handle the requests, and somehow forward them to my app to set up a reply, and have the http server send it again.
Some things I have thought of:
wrap my application in a tomcat application, although I'm not sure if tomcat can run an application continuously instead of mapping to servlets on request.
open a socket and parse incoming http requests myself (or there is propably a lib for that?). I fear this will have an impact on performance, and would rather use existing http servers because they are optimized for high traffic.
use an excisting http server to handle the requests (apache, lighttp, ...) and have it forward requests to my app via things like scgi, or use a server that can forward via XMLRPC. Are there any other technologies/protocols to do this?
Any advice on how to handle this?
Thanks!
I'd decouple your RESTful service endpoint as much as possible from your original application. This allows you to scale (add multiple servers for your REST endpoint), but also to change your original application without having to change your REST API directly.
Clients <== REST (HTTP) ==> RESTful endpoint <== legacy (sockets) ==> Legacy backend
So your REST server is one the hand a service provider for your clients, but represents at the same time also a client for your original backend.
I would design the RESTful API and then pick one of the existing REST frameworks for Java, like Restlet, and implement the REST service itself. At the same time you can start implementing a gateway between the REST server and your original backend, by using sockets.
Pay attention to scalability and performance (i.e. you may want to use connection pools for the rest <=> backend bridge and not spawn a socket per incoming API request) and also think of possible advantages of HTTP. You might benefit when you're able to use caching, etc. as far as your backend application logic allows so.