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  • Should I continue to pursue programming based on my experience?

    - by El Be
    The reason I ask this question is because I am not sure my troubles come from a lack of confidence, or something much deeper like lack of passion. I'm hoping experienced programmers and developers can help identify the cause of my troubles. To be brief my undergraduate major was in Computer Science, but in a small school and I had the highest gpa in my year in computer science. The first time I ever programmed was once in the 5th grade (using logo) and when I was a freshman in college. I enjoyed programming when I was in school. Then I did an internships where I was expected to produce image processing software and program microchips. I was unsuccessful and produced little results and I hated the job, because I had to figure out everything for myself, did not have any help, and there was a lot of pressure to produce results. Although I tried I could not figure out what to do and was stuck all the time and made me dislike the job. When the internship ended I went to a PhD program for computer science at a prestigious computer science school. I had a very hard time with the course, met people who have been programming since they were 6 and made plenty of applications in their spare time (which I never did, although I tried). I even met many sophomores who understood more than I did. The combination of this and other things have made me feel that programming is not for me, but sometimes I consider a career in programming. I still consider programming as a career because of the career potential (not only just because of money). Based on my experience do you believe my confidence has just been shaken and I should continue to prepare for a programming career, or do you see a lack of passion and it would make it tough to continue programming. thank you for reading and for your advice Thank you for everyone's advice so far! Also: I dropped out of the ph.D program for computer science and switched to a master's in computer graphics. Its more applied, but I still find it hard to be motivated (due to either lack of confidence or passion), but since programming is such a big field I am looking for that niche area that I feel good programming in.

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  • What is a typical profit margin for a small, custom software development shop?

    - by jamieb
    I help manage a small (5-15 employees), custom software development shop. We're hired by various clients to produce web or mobile-based applications. We make everything from pretty simple $10k e-commerce websites to very complex applications that might cost $100k over the course of several months. Our clients are generally start-ups, but we also occasionally work with more established companies (including the federal government). I'm just curious what kind of profit margin would be typical for a business fitting this profile?

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  • How can we improve overall Programmer Education & Training?

    - by crosenblum
    Last week, I was just viewing this amazing interview by Kevin Rose of Phillip Rosedale, of Second Life. And they had an amazing discussion about how to find, hire and identify good programmer's, and how hard it is to find good ones. Which has lead me to really think about the way we programmer's learn, are taught. For a majority of us, myself included, we are self-taught. Which is great about being a programmer, anyone can learn and develop skills. But this also means, that there is no real standards of what a good programmer is/are, and what kind of environment's encourage the growth of programming skills. This isn't so much a question, but just a desire in me, to see how we can change the culture of programming, and the manager's of programming, so that education and self-improvement is encouraged. There are a lot of avenue's for continued education, youtube videos, books, conferences, but because of the experiental nature of what we do, it isn't always clear what's important to learn and to master. Let's look at the The Joel 12 Steps. The Joel Test Do you use source control? Can you make a build in one step? Do you make daily builds? Do you have a bug database? Do you fix bugs before writing new code? Do you have an up-to-date schedule? Do you have a spec? Do programmers have quiet working conditions? Do you use the best tools money can buy? Do you have testers? Do new candidates write code during their interview? Do you do hallway usability testing? I think all of these have important value, but because of something I call the Experiential Gap, if a programmer or manager has never experienced any of the negative consequences for not having done items on the list, they will never see the need to do any of them. The Experiental Gap, is my basic theory, that each of us has different jobs and different experiences. So for some of us, that have always worked with dozens of programmer's, source control is a must have. But for people who have always been the only programmer, they can not imagine the need for source control. And it's because of this major flaw in how we learn, that we evaluate people by what best practices they do or not do, and the reason for either can start a flame war. We always evaluate people in our field by what they do, and think "Oh if this guy/gal isn't doing xyz best practice, he/she can't be a good programmer, so let's not waste time or energy talking to them." This is exactly why we have so many programming flame wars, that it becomes, because of the Experiental Gap, we can't imagine people not having made the decisions that we have had to made. So this has lead me to think, that we totally need to rethink how we train, educate and manage programmer's. For example, what percentage of you have had encouragement by your manager's to go to conferences, and even have them pay for it? For me, and a lot of people, this is extremely rare, a lot of us would love to go to conferences, to learn more, but the money ain't there to do that. So the point of this question is really to spark a lot of how can we train, learn and manage better? How can we create a new culture of learning that doesn't insult people for not having the same job experiences. Yes we all have jobs and work to do, but our ability to do our jobs well, depends on our desire, interest and support in improving our mastery of our skills. Right now, I see our culture being rather disorganized, we support the elite, but those tons of us that want to get better, just don't have enough support to learn and improve ourselves. I mean, do we as an industry, want to be perceived as just replaceable cogs? Thank you...

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  • How do I set up MVP for a Winforms solution?

    - by JonWillis
    Question moved from Stackoverflow - http://stackoverflow.com/questions/4971048/how-do-i-set-up-mvp-for-a-winforms-solution I have used MVP and MVC in the past, and I prefer MVP as it controls the flow of execution so much better in my opinion. I have created my infrastructure (datastore/repository classes) and use them without issue when hard coding sample data, so now I am moving onto the GUI and preparing my MVP. Section A I have seen MVP using the view as the entry point, that is in the views constructor method it creates the presenter, which in turn creates the model, wiring up events as needed. I have also seen the presenter as the entry point, where a view, model and presenter are created, this presenter is then given a view and model object in its constructor to wire up the events. As in 2, but the model is not passed to the presenter. Instead the model is a static class where methods are called and responses returned directly. Section B In terms of keeping the view and model in sync I have seen. Whenever a value in the view in changed, i.e. TextChanged event in .Net/C#. This fires a DataChangedEvent which is passed through into the model, to keep it in sync at all times. And where the model changes, i.e. a background event it listens to, then the view is updated via the same idea of raising a DataChangedEvent. When a user wants to commit changes a SaveEvent it fires, passing through into the model to make the save. In this case the model mimics the view's data and processes actions. Similar to #b1, however the view does not sync with the model all the time. Instead when the user wants to commit changes, SaveEvent is fired and the presenter grabs the latest details and passes them into the model. in this case the model does not know about the views data until it is required to act upon it, in which case it is passed all the needed details. Section C Displaying of business objects in the view, i.e. a object (MyClass) not primitive data (int, double) The view has property fields for all its data that it will display as domain/business objects. Such as view.Animals exposes a IEnumerable<IAnimal> property, even though the view processes these into Nodes in a TreeView. Then for the selected animal it would expose SelectedAnimal as IAnimal property. The view has no knowledge of domain objects, it exposes property for primitive/framework (.Net/Java) included objects types only. In this instance the presenter will pass an adapter object the domain object, the adapter will then translate a given business object into the controls visible on the view. In this instance the adapter must have access to the actual controls on the view, not just any view so becomes more tightly coupled. Section D Multiple views used to create a single control. i.e. You have a complex view with a simple model like saving objects of different types. You could have a menu system at the side with each click on an item the appropriate controls are shown. You create one huge view, that contains all of the individual controls which are exposed via the views interface. You have several views. You have one view for the menu and a blank panel. This view creates the other views required but does not display them (visible = false), this view also implements the interface for each view it contains (i.e. child views) so it can expose to one presenter. The blank panel is filled with other views (Controls.Add(myview)) and ((myview.visible = true). The events raised in these "child"-views are handled by the parent view which in turn pass the event to the presenter, and visa versa for supplying events back down to child elements. Each view, be it the main parent or smaller child views are each wired into there own presenter and model. You can literately just drop a view control into an existing form and it will have the functionality ready, just needs wiring into a presenter behind the scenes. Section E Should everything have an interface, now based on how the MVP is done in the above examples will affect this answer as they might not be cross-compatible. Everything has an interface, the View, Presenter and Model. Each of these then obviously has a concrete implementation. Even if you only have one concrete view, model and presenter. The View and Model have an interface. This allows the views and models to differ. The presenter creates/is given view and model objects and it just serves to pass messages between them. Only the View has an interface. The Model has static methods and is not created, thus no need for an interface. If you want a different model, the presenter calls a different set of static class methods. Being static the Model has no link to the presenter. Personal thoughts From all the different variations I have presented (most I have probably used in some form) of which I am sure there are more. I prefer A3 as keeping business logic reusable outside just MVP, B2 for less data duplication and less events being fired. C1 for not adding in another class, sure it puts a small amount of non unit testable logic into a view (how a domain object is visualised) but this could be code reviewed, or simply viewed in the application. If the logic was complex I would agree to an adapter class but not in all cases. For section D, i feel D1 creates a view that is too big atleast for a menu example. I have used D2 and D3 before. Problem with D2 is you end up having to write lots of code to route events to and from the presenter to the correct child view, and its not drag/drop compatible, each new control needs more wiring in to support the single presenter. D3 is my prefered choice but adds in yet more classes as presenters and models to deal with the view, even if the view happens to be very simple or has no need to be reused. i think a mixture of D2 and D3 is best based on circumstances. As to section E, I think everything having an interface could be overkill I already do it for domain/business objects and often see no advantage in the "design" by doing so, but it does help in mocking objects in tests. Personally I would see E2 as a classic solution, although have seen E3 used in 2 projects I have worked on previously. Question Am I implementing MVP correctly? Is there a right way of going about it? I've read Martin Fowler's work that has variations, and I remember when I first started doing MVC, I understood the concept, but could not originally work out where is the entry point, everything has its own function but what controls and creates the original set of MVC objects.

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  • Collision between sprites in game programming?

    - by Lyn Maxino
    I've since just started coding for an android game using eclipse. I've read Beginning Android Game Programming and various other e-books. Recently, I've encountered a problem with collision between sprites. I've used this code template for my program. package com.project.CAI_test; import java.util.Random; import android.graphics.Bitmap; import android.graphics.Canvas; import android.graphics.Rect; public class Sprite { // direction = 0 up, 1 left, 2 down, 3 right, // animation = 3 back, 1 left, 0 front, 2 right int[] DIRECTION_TO_ANIMATION_MAP = { 3, 1, 0, 2 }; private static final int BMP_ROWS = 4; private static final int BMP_COLUMNS = 3; private static final int MAX_SPEED = 5; private GameView gameView; private Bitmap bmp; private int x = 0; private int y = 0; private int xSpeed; private int ySpeed; private int currentFrame = 0; private int width; private int height; public Sprite(GameView gameView, Bitmap bmp) { this.width = bmp.getWidth() / BMP_COLUMNS; this.height = bmp.getHeight() / BMP_ROWS; this.gameView = gameView; this.bmp = bmp; Random rnd = new Random(); x = rnd.nextInt(gameView.getWidth() - width); y = rnd.nextInt(gameView.getHeight() - height); xSpeed = rnd.nextInt(MAX_SPEED * 2) - MAX_SPEED; ySpeed = rnd.nextInt(MAX_SPEED * 2) - MAX_SPEED; } private void update() { if (x >= gameView.getWidth() - width - xSpeed || x + xSpeed <= 0) { xSpeed = -xSpeed; } x = x + xSpeed; if (y >= gameView.getHeight() - height - ySpeed || y + ySpeed <= 0) { ySpeed = -ySpeed; } y = y + ySpeed; currentFrame = ++currentFrame % BMP_COLUMNS; } public void onDraw(Canvas canvas) { update(); int srcX = currentFrame * width; int srcY = getAnimationRow() * height; Rect src = new Rect(srcX, srcY, srcX + width, srcY + height); Rect dst = new Rect(x, y, x + width, y + height); canvas.drawBitmap(bmp, src, dst, null); } private int getAnimationRow() { double dirDouble = (Math.atan2(xSpeed, ySpeed) / (Math.PI / 2) + 2); int direction = (int) Math.round(dirDouble) % BMP_ROWS; return DIRECTION_TO_ANIMATION_MAP[direction]; } public boolean isCollition(float x2, float y2) { return x2 > x && x2 < x + width && y2 > y && y2 < y + height; } } The above code only detects collision between the generated sprites and the surface border. What I want to achieve is a collision detection that is controlled by the update function without having to change much of the coding. Probably several lines placed in the update() function. Tnx for any comment/suggestion.

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  • Reading graph inputs for a programming puzzle and then solving it

    - by Vrashabh
    I just took a programming competition question and I absolutely bombed it. I had trouble right at the beginning itself from reading the input set. The question was basically a variant of this puzzle http://codercharts.com/puzzle/evacuation-plan but also had an hour component in the first line(say 3 hours after start of evacuation). It reads like this This puzzle is a tribute to all the people who suffered from the earthquake in Japan. The goal of this puzzle is, given a network of road and locations, to determine the maximum number of people that can be evacuated. The people must be evacuated from evacuation points to rescue points. The list of road and the number of people they can carry per hour is provided. Input Specifications Your program must accept one and only one command line argument: the input file. The input file is formatted as follows: the first line contains 4 integers n r s t n is the number of locations (each location is given by a number from 0 to n-1) r is the number of roads s is the number of locations to be evacuated from (evacuation points) t is the number of locations where people must be evacuated to (rescue points) the second line contains s integers giving the locations of the evacuation points the third line contains t integers giving the locations of the rescue points the r following lines contain to the road definitions. Each road is defined by 3 integers l1 l2 width where l1 and l2 are the locations connected by the road (roads are one-way) and width is the number of people per hour that can fit on the road Now look at the sample input set 5 5 1 2 3 0 3 4 0 1 10 0 2 5 1 2 4 1 3 5 2 4 10 The 3 in the first line is the additional component and is defined as the number of hours since the resuce has started which is 3 in this case. Now my solution was to use Dijisktras algorithm to find the shortest path between each of the rescue and evac nodes. Now my problem started with how to read the input set. I read the first line in python and stored the values in variables. But then I did not know how to store the values of the distance between the nodes and what DS to use and how to input it to say a standard implementation of dijikstras algorithm. So my question is two fold 1.) How do I take the input of such problems? - I have faced this problem in quite a few competitions recently and I hope I can get a simple code snippet or an explanation in java or python to read the data input set in such a way that I can input it as a graph to graph algorithms like dijikstra and floyd/warshall. Also a solution to the above problem would also help. 2.) How to solve this puzzle? My algorithm was: Find shortest path between evac points (in the above example it is 14 from 0 to 3) Multiply it by number of hours to get maximal number of saves Also the answer given for the variant for the input set was 24 which I dont understand. Can someone explain that also. UPDATE: I get how the answer is 14 in the given problem link - it seems to be just the shortest path between node 0 and 3. But with the 3 hour component how is the answer 24 UPDATE I get how it is 24 - its a complete graph traversal at every hour and this is how I solve it Hour 1 Node 0 to Node 1 - 10 people Node 0 to Node 2- 5 people TotalRescueCount=0 Node 1=10 Node 2= 5 Hour 2 Node 1 to Node 3 = 5(Rescued) Node 2 to Node 4 = 5(Rescued) Node 0 to Node 1 = 10 Node 0 to Node 2 = 5 Node 1 to Node 2 = 4 TotalRescueCount = 10 Node 1 = 10 Node 2= 5+4 = 9 Hour 3 Node 1 to Node 3 = 5(Rescued) Node 2 to Node 4 = 5+4 = 9(Rescued) TotalRescueCount = 9+5+10 = 24 It hard enough for this case , for multiple evac and rescue points how in the world would I write a pgm for this ?

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  • How do you keep your business rules DRY?

    - by Mario
    I periodically ponder how to best design an application whose every business rule exists in just a single location. (While I know there is no proverbial “best way” and that designs are situational, people must have a leaning toward one practice or another.) I work for a shop where they prefer to house as much of the business rules as possible in the database. This requires developers in many cases to perform identical front-end validations to avoid sending data to the database that will result in an exception—not very DRY. It grates me anytime I find myself duplicating any kind of logic—even lowly validation logic. I am a single-point-of-truth purist to an anal degree. On the other end of the spectrum, I know of shops that create dumb databases (the Rails community leans in this direction) and handle all of the business logic in a separate tier (in Rails the models would house “most” of this). Note the word “most” which implies that some business logic does end up spilling into other places (in Rails it might spill over into the controllers). In way, a clean separation of concerns where all business logic exists in a single core location is a Utopian fantasy that’s hard to uphold (n-tiered architecture or not). Furthermore, is see the “Database as a fortress” and would agree that it should be built on constraints that cause it to reject bad data. As such, I hold principles that cause a degree of angst as I attempt to balance them. How do you balance the database-as-a-fortress view with the desire to have a single-point-of-truth?

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  • Place the business logic in Java Beans?

    - by Lirik
    I was reading this page and I found the following statement: MVC in Java Server Pages Now that we have a convenient architucture to separate the view, how can we leverage that? Java Server Pages (JSP) becomes more interesting because the HTML content can be separated from the Java business objects. JSP can also make use of Java Beans. The business logic could be placed inside Java Beans. If the design is architected correctly, a Web Designer could work with HTML on the JSP site without interfering with the Java developer. Interestingly in my textbook I pulled the following quote: In the MVC architecture... the original request is always handled by a servlet. The servlet invokes the business logic and data access code and creates beans to represent the results (that’s the model). Then, the servlet decides which Java Server Page is appropriate to present those particular results and forwards the request there (the JSP is the view). The servlet decides what business logic code applies and which JSP should present the results (the servlet is the controller). The two statements seem slightly contradicting. What is the best way to use beans: should we place business logic in them or should we only place results in them? Are there ways in which beans are inadequate for representing a model?

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  • How to arrange business logic in a Kohana 3 project

    - by Pekka
    I'm looking for advice, tutorials and links at how to set up a mid-sized web application with Kohana 3. I have implemented MVC patterns in the past but never worked against a "formalized" MVC framework so I'm still getting my head around the terminology - toying around with basic examples, building views and templates, and so on. I'm progressing fairly well but I want to set up a real-world web project (one of my own that I've been planning for quite some time now) as a learning object. I learn best by example, but example-based documentation is a bit sparse for Kohana 3 right now - they say so themselves on the site. While I'm not worried about learning the framework as I go along, I want to make sure the code base is healthily structured from the start - i.e. controllers are split nicely, named well and according to standards, and most importantly the business logic is separated into appropriately sized models. My application could, in its core, be described as a business directory with a range of search and listing functions, and a login area for each entry owner. The actual administrative database backend is already taken care of. Supposing I have all the API worked out and in place already - list all businesses, edit business, list businesses by street name, create offer logged in as business, and so on, and I'm just looking for how to fit the functionality into a MVC pattern and into a Kohana application structure that can be easily extended. Do you know real-life examples of "database-heavy" applications like directories, online communities... with a log-in area built on Kohana 3, preferably Open Source so I could take a peek how they do it? Are there conventions or best practices on how to structure an extendable login area for end users in a Kohana project that is not only able to handle a business directory page, but further products on separate pages as well? Do you know any good resources on building complex applications with Kohana? Have you built something similar and could give me recommendations on a project structure?

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  • How can I break into the development business scene if I'm the new kid on the block?

    - by Sergio Tapia
    I'm about 1 semester short of graduating from college with my Systems Engineer degree. I've started my own software development company here in a country in South America last week, and so far I managed to land myself a nice account. I have to build a simple enough program that will take me 6-7weeks to complete and I'll charge 2000$. 40% up front and the rest on completion. While this is great and I'm really excited about my first project (Hell it's a landmark for any professional!), I'm already setting my eye on landing projects that will be visible for other companies to see. I've spoken with many people in my trade around town and it seems there are two companies that manage the big accounts with other small companies scrounging around for the scraps. How can I break this so called fellowship that is pretty much a monopoly here? Any and all suggestions will be massively appreciated.

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  • Small store infrastructure - where to begin?

    - by KevinM1
    It looks like my older brother is about to change jobs - from lawyer to shooting range proprietor - and since I'm the family 'computer guy' I have the task of coming up with and setting up the in-store equipment. Only problem, I don't know how to start or where to look. I'm a web programmer, not an IT specialist. To that end, I figured I should ask the pros. Users: 3 (myself, my brother, and his business partner) Equipment: 1 Windows (likely 7) desktop for POS software, 1 Windows desktop/laptop for backroom use (bookkeeping, etc.) Other: ?? I'm looking for a reliable and, well, idiot-proof way to handle backups. Neither my brother nor his business partner are tech savvy (A web browser, email, MS Word and Excel are about the extent of their knowledge), so I need something they can handle. On-site would be preferable to off-site, given my brother's hesitance to have sensitive business data be handled by an outside source. I'm also looking for a small on-site server. I estimate that, at most, only 2-3 users will need access. A linux solution would keep costs down, but I'm concerned about Windows <- linux interoperability. Would the store security cameras' storage be handled by the security company, or would we have to stream that data to our own server? I know from my own experience with personal security that the company gives/loans a recording device to the home owner, but I'm not sure about business security. I know this sounds like a shopping list, and it's pretty vague. I wish I could give more detail, but between my own ignorance and things not being 100% nailed down on the business end, I'm a bit stuck. At the very least I'd like a nudge - links on a place to start, what to look for, things I need to think about, etc. - for this endeavor. Thanks.

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  • JSF data transfer between UI and business layer

    - by Ram
    Hi, We are using JSF in UI, Spring in business layer, Hibernate in persistence layer. Now my question is how to pass data from the JSF UI to spring business layer. Can I directly use my business object in my backing bean or should I transfer data between the layer through DTO? Can one explain me with clear explanation if possible with piece of code and that related websites?

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  • What's the best scenario for using a wireless router with Comcast Business Class

    - by Buck
    Just had Comcast Business Class internet installed (usage details at bottom of post). During the call to order I asked about the hardware they'd be providing and was told it was a docsis 3 modem that I'd have to pay $7.00/month for. Figuring I'd have to buy a router anyway, I decided to get my own modem - a Surfboard SB6121 Docsis 3. I called in to tech support to ask some questions and learned that the modem they would have provided DID have a router built in. It's an SMCD3G-CCR. It's not wireless (we need wireless). The guy explained that it was better to have their hardware here because if there's a problem with our service and we're using our own hardware, chances are they'll blame it on our hardware and do nothing since they don't support it. He explained that I could still hang my own wireless router off their modem/router and if we ever had any service problems, we'd be able to plug directly into their hardware and they'd be able to tell where the problem is and they wouldn't be able to pawn it off onto "customer provided equipment". That all said, a few questions: 1. Am I better off returning my Surfboard modem and getting the Comcast one? If I get a wireless router and plug into one of the ethernet ports of the Comcast device, should I NOT plug anything else into the Comcast device since it would be a different network from anything connecting via the wireless router? Is that correct? Given that I know VERY LITTLE about networking and setting up hardware like this... since I need wireless and will HAVE to get a wireless router to work with this Comcast device, do I need to do anything with the settings of the Comcast device? Do I use security on the Comcast device or the wireless router or both? Any suggestions or anything I need to think about, given this scenario, in order to use a business-type voip service like RingCentral or Jive or Nextiva? Any recommendations on a wireless router for this scenario? We are running 2 PCs (possibly 3-4 in the future) - could be wired for the time being if needed but would prefer wireless; would like to have a networked hard drive and a networked printer; NEED business-type VOIP service asap for 2 phone lines. Would like to hook up some IP cameras at some point (but not the kind that require static IPs since I don't have one nor do I plan to pay Comcast another $15/month for one). I don't have or plan to have any type of web servers or anything like that. Want to use WPA or WPA2 security and take advantage of the NAT feature of the router for additional protection (that's the extent of my networking knowledge).

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  • How did you get your first programming job?

    - by Gaz
    Hi All, I have some commercial programming experience although it was not my primary role (C# and Java), SCJP 6 cert, some SQL experience and have been doing a lot of Android programming (I have one app with 36,000 downloads). I have a degree in Chemistry and a Diploma in Programming (half a degree made up of 2nd/3rd year uni courses). I'm trying to get my first entry level programmer job but am finding it tough out there.......How did other people get there first jobs in programming?

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  • Business and data layer in ASP.NET MVC

    - by Shetty
    Hi, I am new to ASP.net MVC architecture. I have read in some articles that Model will contain business and data access logic. So does this mean that i have to implement the business and data access layrers in side model folder? And it is obviously not possible to add class libraries (business layer and Data access layer of n tier) in Model folder. SO please let me know how to design business and data layer if i dont want to include my LINQ queries in Controller. Thanks, Amith

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  • When does logic belong in the Business Object/Entity, and when does it belong in a Service?

    - by Casey
    In trying to understand Domain Driven Design I keep returning to a question that I can't seem to definitively answer. How do you determine what logic belongs to a Domain entity, and what logic belongs to a Domain Service? Example: We have an Order class for an online store. This class is an entity and an aggregate root (it contains OrderItems). Public Class Order:IOrder { Private List<IOrderItem> OrderItems Public Order(List<IOrderItem>) { OrderItems = List<IOrderItem> } Public Decimal CalculateTotalItemWeight() //This logic seems to belong in the entity. { Decimal TotalWeight = 0 foreach(IOrderItem OrderItem in OrderItems) { TotalWeight += OrderItem.Weight } return TotalWeight } } I think most people would agree that CalculateTotalItemWeight belongs on the entity. However, at some point we have to ship this order to the customer. To accomplish this we need to do two things: 1) Determine the postage rate necessary to ship this order. 2) Print a shipping label after determining the postage rate. Both of these actions will require dependencies that are outside the Order entity, such as an external webservice to retrieve postage rates. How should we accomplish these two things? I see a few options: 1) Code the logic directly in the domain entity, like CalculateTotalItemWeight. We then call: Order.GetPostageRate Order.PrintLabel 2) Put the logic in a service that accepts IOrder. We then call: PostageService.GetPostageRate(Order) PrintService.PrintLabel(Order) 3) Create a class for each action that operates on an Order, and pass an instance of that class to the Order through Constructor Injection (this is a variation of option 1 but allows reuse of the RateRetriever and LabelPrinter classes): Public Class Order:IOrder { Private List<IOrderItem> OrderItems Private RateRetriever _Retriever Private LabelPrinter _Printer Public Order(List<IOrderItem>, RateRetriever Retriever, LabelPrinter Printer) { OrderItems = List<IOrderItem> _Retriever = Retriever _Printer = Printer } Public Decimal GetPostageRate { _Retriever.GetPostageRate(this) } Public void PrintLabel { _Printer.PrintLabel(this) } } Which one of these methods do you choose for this logic, if any? What is the reasoning behind your choice? Most importantly, is there a set of guidelines that led you to your choice?

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  • JSF Data transfer between UI to Business Layers

    - by Ram
    Hi, We are using JSF in UI,Spring in Business Layer,Hibernate in Persistance layer.Now my question is how to pass data from my JSF1.1_01 UI to spring Business Layer.Can I directly used my Business object in my Backed Bean or through DTO should I transfer data between the layer? Can one explain me with clear explanation if possible with piece of code and that related websites?

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  • Business Units vs Teams in CRM 2011

    - by GuruJ
    I've been told a few times that Business Units in CRM 2011 are "tricky" and shouldn't be set up lightly since they have irreversible consequences for a CRM 2011 implementation. On the other hand, teams in CRM 2011 seem much more flexible in managing record security. For what reason would I still choose to set up Business Units in CRM 2011? What can I do with Business Units that I can't with Teams (and vice versa)?

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  • An Alphabet of Eponymous Aphorisms, Programming Paradigms, Software Sayings, Annoying Alliteration

    - by Brian Schroer
    Malcolm Anderson blogged about “Einstein’s Razor” yesterday, which reminded me of my favorite software development “law”, the name of which I can never remember. It took much Wikipedia-ing to find it (Hofstadter’s Law – see below), but along the way I compiled the following list: Amara’s Law: We tend to overestimate the effect of a technology in the short run and underestimate the effect in the long run. Brook’s Law: Adding manpower to a late software project makes it later. Clarke’s Third Law: Any sufficiently advanced technology is indistinguishable from magic. Law of Demeter: Each unit should only talk to its friends; don't talk to strangers. Einstein’s Razor: “Make things as simple as possible, but not simpler” is the popular paraphrase, but what he actually said was “It can scarcely be denied that the supreme goal of all theory is to make the irreducible basic elements as simple and as few as possible without having to surrender the adequate representation of a single datum of experience”, an overly complicated quote which is an obvious violation of Einstein’s Razor. (You can tell by looking at a picture of Einstein that the dude was hardly an expert on razors or other grooming apparati.) Finagle's Law of Dynamic Negatives: Anything that can go wrong, will—at the worst possible moment. - O'Toole's Corollary: The perversity of the Universe tends towards a maximum. Greenspun's Tenth Rule: Any sufficiently complicated C or Fortran program contains an ad hoc, informally-specified, bug-ridden, slow implementation of half of Common Lisp. (Morris’s Corollary: “…including Common Lisp”) Hofstadter's Law: It always takes longer than you expect, even when you take into account Hofstadter's Law. Issawi’s Omelet Analogy: One cannot make an omelet without breaking eggs - but it is amazing how many eggs one can break without making a decent omelet. Jackson’s Rules of Optimization: Rule 1: Don't do it. Rule 2 (for experts only): Don't do it yet. Kaner’s Caveat: A program which perfectly meets a lousy specification is a lousy program. Liskov Substitution Principle (paraphrased): Functions that use pointers or references to base classes must be able to use objects of derived classes without knowing it Mason’s Maxim: Since human beings themselves are not fully debugged yet, there will be bugs in your code no matter what you do. Nils-Peter Nelson’s Nil I/O Rule: The fastest I/O is no I/O.    Occam's Razor: The simplest explanation is usually the correct one. Parkinson’s Law: Work expands so as to fill the time available for its completion. Quentin Tarantino’s Pie Principle: “…you want to go home have a drink and go and eat pie and talk about it.” (OK, he was talking about movies, not software, but I couldn’t find a “Q” quote about software. And wouldn’t it be cool to write a program so great that the users want to eat pie and talk about it?) Raymond’s Rule: Computer science education cannot make anybody an expert programmer any more than studying brushes and pigment can make somebody an expert painter.  Sowa's Law of Standards: Whenever a major organization develops a new system as an official standard for X, the primary result is the widespread adoption of some simpler system as a de facto standard for X. Turing’s Tenet: We shall do a much better programming job, provided we approach the task with a full appreciation of its tremendous difficulty, provided that we respect the intrinsic limitations of the human mind and approach the task as very humble programmers.  Udi Dahan’s Race Condition Rule: If you think you have a race condition, you don’t understand the domain well enough. These rules didn’t exist in the age of paper, there is no reason for them to exist in the age of computers. When you have race conditions, go back to the business and find out actual rules. Van Vleck’s Kvetching: We know about as much about software quality problems as they knew about the Black Plague in the 1600s. We've seen the victims' agonies and helped burn the corpses. We don't know what causes it; we don't really know if there is only one disease. We just suffer -- and keep pouring our sewage into our water supply. Wheeler’s Law: All problems in computer science can be solved by another level of indirection... Except for the problem of too many layers of indirection. Wheeler also said “Compatibility means deliberately repeating other people's mistakes.”. The Wrong Road Rule of Mr. X (anonymous): No matter how far down the wrong road you've gone, turn back. Yourdon’s Rule of Two Feet: If you think your management doesn't know what it's doing or that your organisation turns out low-quality software crap that embarrasses you, then leave. Zawinski's Law of Software Envelopment: Every program attempts to expand until it can read mail. Zawinski is also responsible for “Some people, when confronted with a problem, think 'I know, I'll use regular expressions.' Now they have two problems.” He once commented about X Windows widget toolkits: “Using these toolkits is like trying to make a bookshelf out of mashed potatoes.”

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  • "Guiding" a Domain Expert to Retire from Programming

    - by James Kolpack
    I've got a friend who does IT at a local non-profit where they're using a custom web application which is no longer supported by the company who built it. (out of business, support was too expensive, I'm not sure...) Development on this app started around 10+ years ago so the technologies being harnessed are pretty out of date now - classic asp using vbscript and SQL Server 2000. The application domain is in the realm of government bookkeeping - so even though the development team is long gone, there are often new requirements of this software. Enter the... The domain expert. This is an middle aged accounting whiz without much (or any?) prior development experience. He studied the pages, code and queries and learned how to ape the style of the original team which, believe me, is mediocre at best. He's very clever and very tenacious but has no experience in software beyond what he's picked up from this app. Otherwise, he's a pleasant guy to talk to and definitely knows his domain. My friend in IT, and probably his superiors in the company, want him out of the code. They view him as wasting his expertise on coding tasks he shouldn't be doing. My friend got me involved with a few small contracts which I handled without much problem - other than somewhat of a communication barrier with the domain expert. He explained the requirements very quickly, assuming prior knowledge of the domain which I do not have. This is partially his normal style, and I think maybe a bit of resentment from my involvement. So, I think he feels like the owner of the code and has entrenched himself in a development position. So... his coding technique. One of his latest endeavors was to make a page that only he could reach (theoretically - the security model for the system is wretched) where he can enter a raw SQL query, run it, and save the query to run again later. A report that I worked on had been originally implemented by him using 6 distinct queries, 3 or 4 temp tables to coordinate the data between the queries, and the final result obtained by importing the data from the final query into Access and doing a pivot and some formatting. It worked - well, some of the results were incorrect - but at what a cost! (I implemented the report in a single query with at least 1/10th the amount of code.) He edits code in notepad. He doesn't seem to know about online reference material for the languages. I recently read an article on Dr. Dobbs titled "What Makes Bad Programmers Different" - and instantly thought of our domain expert. From the article: Their code is large, messy, and bug laden. They have very superficial knowledge of their problem domain and their tools. Their code has a lot of copy/paste and they have very little interest in techniques that reduce it. The fail to account for edge cases, while inefficiently dealing with the general case. They never have time to comment their code or break it into smaller pieces. Empirical evidence plays no little role in their decisions. 5.5 out of 6. My friend is wanting me to argue the case to their management - specifically, I got this email from their manager to respond to: ...Also, I need to talk to you about what effect there is from Domain Expert continuing to make edits to the live environment. If that is a problem for you I need to know so I can have his access blocked. Some examples would help. In my opinion, from a technical standpoint, it's dangerous to have him making changes without any oversight. On the other hand, I'm just doing one-off contracts at this point and don't have much desire to get involved deeply enough that I'm essentially arguing as one of the Bobs from Office Space. I'd like to help my friend out - but I feel like I'm getting in the middle of a political battle. More importantly - if I do get involved and suggest that his editing privileges be removed, it needs to be handled carefully so that doesn't feel belittled. He is beyond a doubt the foremost expert on this system. I'm hoping this is familiar territory for some other stackechangers, because I'm feeling a little bewildered. How should I respond? Should I argue that he shouldn't be allowed to touch the code? Should I phrase it as "no single developer, no matter how experienced, should be working on production code unchecked"? Should I argue to keep him involved with the code, but with a review process? Should I say "glad I could help, but uh, I'm busy now!" Other options? Thanks a bunch!

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  • Quadratic Programming with Oracle R Enterprise

    - by Jeff Taylor-Oracle
         I wanted to use quadprog with ORE on a server running Oracle Solaris 11.2 on a Oracle SPARC T-4 server For background, see: Oracle SPARC T4-2 http://docs.oracle.com/cd/E23075_01/ Oracle Solaris 11.2 http://www.oracle.com/technetwork/server-storage/solaris11/overview/index.html quadprog: Functions to solve Quadratic Programming Problems http://cran.r-project.org/web/packages/quadprog/index.html Oracle R Enterprise 1.4 ("ORE") 1.4 http://www.oracle.com/technetwork/database/options/advanced-analytics/r-enterprise/ore-downloads-1502823.html Problem: path to Solaris Studio doesn't match my installation: $ ORE CMD INSTALL quadprog_1.5-5.tar.gz * installing to library \u2018/u01/app/oracle/product/12.1.0/dbhome_1/R/library\u2019 * installing *source* package \u2018quadprog\u2019 ... ** package \u2018quadprog\u2019 successfully unpacked and MD5 sums checked ** libs /opt/SunProd/studio12u3/solarisstudio12.3/bin/f95 -m64   -PIC  -g  -c aind.f -o aind.o bash: /opt/SunProd/studio12u3/solarisstudio12.3/bin/f95: No such file or directory *** Error code 1 make: Fatal error: Command failed for target `aind.o' ERROR: compilation failed for package \u2018quadprog\u2019 * removing \u2018/u01/app/oracle/product/12.1.0/dbhome_1/R/library/quadprog\u2019 $ ls -l /opt/solarisstudio12.3/bin/f95 lrwxrwxrwx   1 root     root          15 Aug 19 17:36 /opt/solarisstudio12.3/bin/f95 -> ../prod/bin/f90 Solution: a symbolic link: $ sudo mkdir -p /opt/SunProd/studio12u3 $ sudo ln -s /opt/solarisstudio12.3 /opt/SunProd/studio12u3/ Now, it is all good: $ ORE CMD INSTALL quadprog_1.5-5.tar.gz * installing to library \u2018/u01/app/oracle/product/12.1.0/dbhome_1/R/library\u2019 * installing *source* package \u2018quadprog\u2019 ... ** package \u2018quadprog\u2019 successfully unpacked and MD5 sums checked ** libs /opt/SunProd/studio12u3/solarisstudio12.3/bin/f95 -m64   -PIC  -g  -c aind.f -o aind.o /opt/SunProd/studio12u3/solarisstudio12.3/bin/ cc -xc99 -m64 -I/usr/lib/64/R/include -DNDEBUG -KPIC  -xlibmieee  -c init.c -o init.o /opt/SunProd/studio12u3/solarisstudio12.3/bin/f95 -m64  -PIC -g  -c -o solve.QP.compact.o solve.QP.compact.f /opt/SunProd/studio12u3/solarisstudio12.3/bin/f95 -m64  -PIC -g  -c -o solve.QP.o solve.QP.f /opt/SunProd/studio12u3/solarisstudio12.3/bin/f95 -m64   -PIC  -g  -c util.f -o util.o /opt/SunProd/studio12u3/solarisstudio12.3/bin/ cc -xc99 -m64 -G -o quadprog.so aind.o init.o solve.QP.compact.o solve.QP.o util.o -xlic_lib=sunperf -lsunmath -lifai -lsunimath -lfai -lfai2 -lfsumai -lfprodai -lfminlai -lfmaxlai -lfminvai -lfmaxvai -lfui -lfsu -lsunmath -lmtsk -lm -lifai -lsunimath -lfai -lfai2 -lfsumai -lfprodai -lfminlai -lfmaxlai -lfminvai -lfmaxvai -lfui -lfsu -lsunmath -lmtsk -lm -L/usr/lib/64/R/lib -lR installing to /u01/app/oracle/product/12.1.0/dbhome_1/R/library/quadprog/libs ** R ** preparing package for lazy loading ** help *** installing help indices   converting help for package \u2018quadprog\u2019     finding HTML links ... done     solve.QP                                html      solve.QP.compact                        html  ** building package indices ** testing if installed package can be loaded * DONE (quadprog) ====== Here is an example from http://cran.r-project.org/web/packages/quadprog/quadprog.pdf > require(quadprog) > Dmat <- matrix(0,3,3) > diag(Dmat) <- 1 > dvec <- c(0,5,0) > Amat <- matrix(c(-4,-3,0,2,1,0,0,-2,1),3,3) > bvec <- c(-8,2,0) > solve.QP(Dmat,dvec,Amat,bvec=bvec) $solution [1] 0.4761905 1.0476190 2.0952381 $value [1] -2.380952 $unconstrained.solution [1] 0 5 0 $iterations [1] 3 0 $Lagrangian [1] 0.0000000 0.2380952 2.0952381 $iact [1] 3 2 Here, the standard example is modified to work with Oracle R Enterprise require(ORE) ore.connect("my-name", "my-sid", "my-host", "my-pass", 1521) ore.doEval(   function () {     require(quadprog)   } ) ore.doEval(   function () {     Dmat <- matrix(0,3,3)     diag(Dmat) <- 1     dvec <- c(0,5,0)     Amat <- matrix(c(-4,-3,0,2,1,0,0,-2,1),3,3)     bvec <- c(-8,2,0)    solve.QP(Dmat,dvec,Amat,bvec=bvec)   } ) $solution [1] 0.4761905 1.0476190 2.0952381 $value [1] -2.380952 $unconstrained.solution [1] 0 5 0 $iterations [1] 3 0 $Lagrangian [1] 0.0000000 0.2380952 2.0952381 $iact [1] 3 2 Now I can combine the quadprog compute algorithms with the Oracle R Enterprise Database engine functionality: Scale to large datasets Access to tables, views, and external tables in the database, as well as those accessible through database links Use SQL query parallel execution Use in-database statistical and data mining functionality

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  • Scala programming language for beginners, is it a legend?

    - by ali
    Hi every one, I am Ali from Saudi Arabia. undoubtedly, Scala is one of the best programming language for any programmer to learn, but there is "good" problems that is faced especially by beginners, and what seems frustrating that these problems won't solve soon, so as a beginner and on behalf of beginners let me raise these "objective" questions: 1- why scala has no effective and stable development platform, in fact, it suffers many problems with Eclipse, Netbeat, and Intellij. 2- although I have looked for a clear,easy, and understandable explanation of how to get started with Scala, but fortunately, there was no article or guide that deserves to spend the time I have spent to read it. nobody could tell you clear steps that fit you as a beginner who wants to start his"HELLO WORLD" with Scala, while all other languages have its "HELLO WORLD" guides and books. thank you for your time, be sure that you read notes below. 1- I have no experience in programming language before. 2- don't tell me "not to begin with scala", simply, because I will do. 3- OS is windows vista home premium. 4- I hate excuses, such as Scala is new language......etc

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