Constantly changing data [closed] - java

As it currently stands, this question is not a good fit for our Q&A format. We expect answers to be supported by facts, references, or expertise, but this question will likely solicit debate, arguments, polling, or extended discussion. If you feel that this question can be improved and possibly reopened, visit the help center for guidance.
Closed 10 years ago.
This is my first question on StackOverflow. I'm new to it all. I know you're all pretty strict here, so I did all the research I could before asking this. Unfortunately I came up empty.
I'm building an app that shows an event that occurs every three months. This event has different shows in it that change very often. That is where my app comes in, it keeps people updated on what will be happening at the event. So when the event planners change their schedule, I need it to update my users. Pictures need to be changed too. Obviously, having them update the app is not the easiest way.
I know I could build a webpage, and have the app read off that. But I am really hoping there is an easier way than that. And if the webpage IS the only way, what is the best api?
So my question is; What is the easiest way to do this, so I can do more research about it?

https://www.parse.com/
Parse might be your best option if all you need is some basic data on a server. You don't need to write a whole web application or scrape html off of a web page. If you need other non technical users to write this data, you can make one "manager" version of your app and include some authentication logic (which you could also do against your Parse account). I have done this kind of thing using Amazon S3 buckets when I didn't have the time to write a whole web app just for some very basic server interaction for a mobile app.

You're going to want to have a server that your app can talk to. I would do this in two parts that have to happen more or less at the same pace. First, I would use Google's Cloud Messaging API to do the "light lifting" - it lets your app do a small check to see if anything needs updating. Then I would set up the server. You're obviously going to need to learn how to open up connections, downloads, storage, etc.
Important thing to keep in mind though, efficiency. Be smart about the data transimitted. Keeping it simple will benefit your app (less code, more straightforward) and your users (smaller app, less data usage).
But first, do research, try stuff out and don't be afraid to ask questions.

you don't need to build a webpage, you just need a server that the app can query

Related

JSF performance limit [closed]

As it currently stands, this question is not a good fit for our Q&A format. We expect answers to be supported by facts, references, or expertise, but this question will likely solicit debate, arguments, polling, or extended discussion. If you feel that this question can be improved and possibly reopened, visit the help center for guidance.
Closed 9 years ago.
I have a sort of unusual question, and I know it is a very controversial, but here it comes.
I have developed a few JSF applications in the past but these all limit the amount of users that can be servred about 5-6. This was partly because of a license based policy. I performed some tests with 20+ users and Selenium, and the applications went really slow. The problem was probably originating from the server's performance but still, I can't help to ask the following question:
Can a JSF application support a large number of users? My bet would be that the framework should allow it, however I can't think of any commercial website that uses JSF and can support thousands of users at a time. (If you could show me some that would be great!)
I ask this, because I have been asked to develop a larger system, and I would love to use JSF because I love it very much, however the recent performance tests gave me doubts. The lead programmer said it is only the server machine's perfomance that is the issue, but in that case, what kind of machine can support thousands of users logged in at the same time? The lead programmer is not the best of it's kind, that is why I want to hear a second opinion from SOF if you dont mind.
If there is any framework more suitable for extreme use please let me know which one it is, the only real constraint I have is that it should be Java based on the server side.
Again my apologies for the unconstructive question.
these all limit the amount of users that can be servred about 5-6
Not sure what the app's load or design are, but that sounds unbelievably low. JSF should be able to handle many 100s of users if designed right or even 1000s with the right infrastructure. JSF code runs with servlets and facelets - the framework is standard code on top of these, that has been optimized over time and gets JIT optimised at runtime.
E.g. With IBM Websphere Portal Server and Oracle Portal, the standard way to build customer portals and apps is via JSF. And they're used in massive installations.
Sounds like your past app(s) have some problem. I don't think you can blame that performance on JSF.
If you want an extreme number of connection is Java you might consider http://netty.io/ It is designed to support and has been tested for 100,000+ connections.
I suspect the bottleneck is not the number of connections you have but how efficient you serve up pages i.e. you JSF is particularly slow. If you optimise that I suspect you can handle more connections.

What is Websphere? [closed]

As it currently stands, this question is not a good fit for our Q&A format. We expect answers to be supported by facts, references, or expertise, but this question will likely solicit debate, arguments, polling, or extended discussion. If you feel that this question can be improved and possibly reopened, visit the help center for guidance.
Closed 9 years ago.
Googling this question returns lots of results with marketing jargon.
What I am looking for is a summary of what it does, more along these lines What is Maven?
This is the closest I could get.
"WebSphere" in the most abstract sense is a brand encompassing various products, so "a brand" is about as good an answer as you can get.
What one usually refers to when saying "WebSphere", though, is the WebSphere Application Server, which (as the name implies) is an application server - something that runs EJBs and other server-side Java technologies like servlets, JMS, etc. An example of another important player in this space is JBoss AS.
Finally, another possible definition of "WebSphere" is "its creator's biggest technology mistake" ;)
Unlike a regular web server which simply provides clients acces to html-documents, which their browser then displays as websites, an application server allows for programms/scripts to be invoked by requesting websites, which dynamically generate the websites.
In this case the scripts are written in Java. This allows for a lot of the apis provieded in Java to be utilised by your web-application (the website itself is simply the frontend of your webapplication)
So web sphere is an application server from IBM. Simple as that. This tells you what it can do.
Hope that helps.
WebSphere is an application server which supports a lot of advanced functions including load balancing, database connection managing, advanced logging options and many more.
On the other hand it introduces severe overhead, is difficult to administrate and one has to learn a lot to use it effectively. And more often than on other servers you find yourself in JAR hell. Been there.

Hard Coded SQL statements VS. Web Service to execute the queries [closed]

As it currently stands, this question is not a good fit for our Q&A format. We expect answers to be supported by facts, references, or expertise, but this question will likely solicit debate, arguments, polling, or extended discussion. If you feel that this question can be improved and possibly reopened, visit the help center for guidance.
Closed 10 years ago.
I'm developing a Java application that communicates with a MySQL database in a server. The app should be able to read some data from an XML file and then insert the info read into the database.
I used to write SQL Statements directly to the Java code, but then a friend advised me to create a web service that does all the SQL stuff for the tool, and let the tool's only job is to read XML and send data into the web service.
My question is, does it deserve that effort? Why or Why not?
SQL in code is not recommended as it becomes difficult to maintain. The application is also tightly coupled to the database structure. Every time the database change (or you are moving to a new database) you need to make changes to your code and release again.
I don't think a web service is the correct answer here. I would recommend you try one of the following:
If your application uses a lot of tables and very high throughput is not critical, use Hibernate as an ORM tool. It has many features and can really reduce the time spent on data access.
If you do not have that many tables and you don't have the time to learn Hibernate, use iBatis. It will take you 30 minutes to grasp. It essentially allows you to put your SQL in a separate XML file, which it will read for you. For smaller applications it is really useful and it is faster than Hibernate.
As a last resort, rather put your SQL in a text file(s) which you open and execute.
How do you intend to create the webservice part? If you have the time to do, worth trying with Core Java or any Webservice framework, though I would suggest use Core java which would help to keep minimal dependency for your tool. Nevertheless, there is an ample amount of effort required to get the XML and Webservice requests in sync. My take - if it is not broken, dont fix it.

what is the knowledge i have to know to make centrelized DB in PC and access it via internet using java application? [closed]

As it currently stands, this question is not a good fit for our Q&A format. We expect answers to be supported by facts, references, or expertise, but this question will likely solicit debate, arguments, polling, or extended discussion. If you feel that this question can be improved and possibly reopened, visit the help center for guidance.
Closed 10 years ago.
i want to make centralized MySQL DB in PC like server ,
and manipulate it via internet using java application .
i have already learn MySQL and java ,but i can't reach which i want.
what is the knowledge i have to know to make this ?
some detailed description about my project :
i work at a community as a data administrator which have many activities.
in each activity there is many clients and workers deal with this activity.
i have a team work with me , for each activity has a 1 data team member responsible for it (entering data , updating , making reports).
we make all this with MS Excel,but the data is increasing and i can't manage it.
so i think to make a program help me to manage all these data , but we need one database to hold these data not many database, to union it and every one can work at home.
so, i need some one refers to tutorials and books to make this program .
A web application would be a solution for your problems.
For that you would need to know how to configure and work with a server like JBoss for example. Further you'll be needing servlets or some mvc framework like spring for example. There are so many possibilities; sounds to me like you should find someone who can do this for you.

Backend Server Scripts [closed]

As it currently stands, this question is not a good fit for our Q&A format. We expect answers to be supported by facts, references, or expertise, but this question will likely solicit debate, arguments, polling, or extended discussion. If you feel that this question can be improved and possibly reopened, visit the help center for guidance.
Closed 11 years ago.
I have a system that the backend currently relies on Python.
Basically it has a series of scripts that will go through a MySQL database and check for certain parameters across multiple tables and then perform actions such as send emails and text messages then amend relevant cells to say these issues were dealt with. There is then another script that sits and listens on a port for UDP packets, unpacks them validates them and if they pass validation inserts them into the database and check to see if the data triggers any alarms will send an email and tech message.
My question is am I doing this the most efficient way? As I am not sure how to have a system of checking to see if the scripts are running and if not relaunch them. All of them run infinitely 24/7. Would rewriting them in Java be more stable and efficient?
There is no real way to answer either question without knowing all aspects of the system.
If your system basically have 2 scripts written in Python that perform well I don't see any reason whatsoever to change that architecture. One more consideration that I would give you to ponder is that at least one of these scripts is a support script and the guys responsible for support mostly don't care much about Java to be able to troubleshoot the code.
As far as JAVA is concerned I am not sure that you would be better off with Java then you are with Python. There is no shortage of expertise out there in either language but given what the programs are used for I'd say Python would be a better choice. If you are concerned about performance though I would look at Cython as a possiblity.

Categories

Resources