Daily Archives

Articles indexed Thursday October 24 2013

Page 16/18 | < Previous Page | 12 13 14 15 16 17 18  | Next Page >

• how to improve design ability

  - by Cong Hui

  I recently went on a couple of interviews and all of them asked a one or two design questions, like how you would design a chess, monopoly, and so on. I didn't do good on those since I am a college student and lack of the experience of implementing big and complex systems. I figure the only way to improve my design capability is to read lots of others' code and try to implement myself. Therefore, for those companies that ask these questions, what are their real goals in this? I figure most of college grads start off working in a team guided by a senior leader in their first jobs. They might not have lots of design experience fresh out of colleges. Anyone could give pointers about how to practice those skills? Thank you very much

  Read the article

• Why isn't there a typeclass for functions?

  - by Steve314

  I already tried this on Reddit, but there's no sign of a response - maybe it's the wrong place, maybe I'm too impatient. Anyway... In a learning problem I've been messing around with, I realised I needed a typeclass for functions with operations for applying, composing etc. Reasons... It can be convenient to treat a representation of a function as if it were the function itself, so that applying the function implicitly uses an interpreter, and composing functions derives a new description. Once you have a typeclass for functions, you can have derived typeclasses for special kinds of functions - in my case, I want invertible functions. For example, functions that apply integer offsets could be represented by an ADT containing an integer. Applying those functions just means adding the integer. Composition is implemented by adding the wrapped integers. The inverse function has the integer negated. The identity function wraps zero. The constant function cannot be provided because there's no suitable representation for it. Of course it doesn't need to spell things as if it the values were genuine Haskell functions, but once I had the idea, I thought a library like that must already exist and maybe even using the standard spellings. But I can't find such a typeclass in the Haskell library. I found the Data.Function module, but there's no typeclass - just some common functions that are also available from the Prelude. So - why isn't there a typeclass for functions? Is it "just because there isn't" or "because it's not so useful as you think"? Or maybe there's a fundamental problem with the idea? The biggest possible problem I've thought of so far is that function application on actual functions would probably have to be special-cased by the compiler to avoid a looping problem - in order to apply this function I need to apply the function application function, and to do that I need to call the function application function, and to do that...

  Read the article

• Simple alternating text in Visual Basic 2008

  - by Josh Grate

  I have a simple completed program, but i would like to add one more feature to it but I'm not sure how. I have it set up to send a message automatically every 7 seconds when a text field is selected, repeating the message of course. What I would like for it to do is alternate between two separate messages, instead just repeating the one. I would like the new program to post at an interval of 12 seconds. Can you help me? Here is my coding. Public Class Form1 Private Sub Timer1_Tick(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Timer1.Tick SendKeys.Send(TextBox1.Text) SendKeys.Send("{ENTER}") End Sub Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click Timer1.Enabled = True Timer1.Interval = (TextBox2.Text) End Sub Private Sub Button2_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button2.Click Timer1.Enabled = False End Sub Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load Timer1.Enabled = False End Sub End Class

  Read the article

• Missing return statement when using .charAt [migrated]

  - by Timothy Butters

  I need to write a code that returns the number of vowels in a word, I keep getting an error in my code asking for a missing return statement. Any solutions please? :3 import java.util.*; public class vowels { public static void main(String[] args) { Scanner input = new Scanner(System.in); System.out.println("Please type your name."); String name = input.nextLine(); System.out.println("Congratulations, your name has "+ countVowels(name) +" vowels."); } public static int countVowels(String str) { int count = 0; for (int i=0; i < str.length(); i++) { // char c = str.charAt(i); if (str.charAt(i) == 'a' || str.charAt(i) == 'e' || str.charAt(i) == 'o' || str.charAt(i) == 'i' || str.charAt(i) == 'u') count = count + 1; } } }

  Read the article

• What are the safety benefits of a type system?

  - by vandros526

  In Javascript: The Good Parts by Douglas Crockford, he mentions in his inheritance chapter, "The other benefit of classical inheritance is that it includes the specification of a system of types. This mostly frees the programmer from having to write explicit casting operations, which is a very good thing because when casting, the safety benefits of a type system are lost." So first of all, what actually is safety? protection against data corruption, or hackers, or system malfunctions, etc? What are the safety benefits of a type system? What makes a type system different that allows it to provide these safety benefits?

  Read the article

• Information I need to know as a Java Developer [on hold]

  - by Woy

  I'm a java developer. I'm trying to get more knowledge to become a better programmer. I've listed a number of technologies to learn. Instead of what I've listed, what technologies would you suggest to learn as well for a Junior Java Developer? I realize, there's a lot of things to study. Java: - how a garbage collector works - resource management - network programming - TCP/IP HTTP - transactions, - consistency: interfaces, classes collections, hash codes, algorithms, comp. complexity concurrent programming: synchronizing, semafores steam management metability: thread-safety byte code manipulations, reflections, Aspect-Oriented Programming as base to understand frameworks such as Spring etc. Web stack: servlets, filters, socket programming Libraries: JDK, GWT, Apache Commons, Joda-Time, Dependency Injections: Spring, Nano Tools: IDE: very good knowledge - debugger - profiler - web analyzers: Wireshark, firebugs - unit testing SQL/Databases: Basics SELECTing columns from a table Aggregates Part 1: COUNT, SUM, MAX/MIN Aggregates Part 2: DISTINCT, GROUP BY, HAVING + Intermediate JOINs, ANSI-89 and ANSI-92 syntax + UNION vs UNION ALL x NULL handling: COALESCE & Native NULL handling Subqueries: IN, EXISTS, and inline views Subqueries: Correlated ITH syntax: Subquery Factoring/CTE Views Advanced Topics Functions, Stored Procedures, Packages Pivoting data: CASE & PIVOT syntax Hierarchical Queries Cursors: Implicit and Explicit Triggers Dynamic SQL Materialized Views Query Optimization: Indexes Query Optimization: Explain Plans Query Optimization: Profiling Data Modelling: Normal Forms, 1 through 3 Data Modelling: Primary & Foreign Keys Data Modelling: Table Constraints Data Modelling: Link/Corrollary Tables Full Text Searching XML Isolation Levels Entity Relationship Diagrams (ERDs), Logical and Physical Transactions: COMMIT, ROLLBACK, Error Handling

  Read the article

• How do I run Conkeror in Emacs?

  - by Anake

  I have been using emacs for about 3 months, and have been amazed by how much improved my interactions with my computer are. I now use eshell rather than a separate terminal, and the last thing I still need to leave my emacs environment for is for my web browser. I have been reading up on Conkeror, and it seems almost ideal (emacs keybindings, no need to use the mouse etc.) but it runs in a separate window. If it could be run within emacs, it would mean that I would never really have to have interaction with the actual OS, which would be good for someone who is forced to rotate between linux, mac and windows (i.e. me). I understand that it couldn't be run from emacs in -nw mode, but would it be possible (or likely) that Conkeror could be setup to run within an emacs window? Note: - I've tried w3m and didn't really like it

  Read the article

• I don't understand how TDD helps me get a good design if I need a design to start testing it

  - by Michael Stum

  I'm trying to wrap my head around TDD, specifically the development part. I've looked at some books, but the ones I found mainly tackle the testing part - the History of NUnit, why testing is good, Red/Green/Refactor and how to create a String Calculator. Good stuff, but that's "just" Unit Testing, not TDD. Specifically, I don't understand how TDD helps me get a good design if I need a Design to start testing it. To illustrate, imagine these 3 requirements: A catalog needs to have a list of products The catalog should remember which products a user viewed Users should be able to search for a product At this points, many books pull a magic rabbit out of a hat and just dive into "Testing the ProductService", but they don't explain how they came to the conclusion that there is a ProductService in the first place. That is the "Development" part in TDD that I'm trying to understand. There needs to be an existing design, but stuff outside of entity-services (that is: There is a Product, so there should be a ProductService) is nowhere to be found (e.g., the second requirement requires me to have some concept of a User, but where would I put the functionality to remind? And is Search a feature of the ProductService or a separate SearchService? How would I know which I should choose?) According to SOLID, I would need a UserService, but if I design a system without TDD, I might end up with a whole bunch of Single-Method Services. Isn't TDD intended to make me discover my design in the first place? I'm a .net developer, but Java resources would also work. I feel that there doesn't seem to be a real sample application or book that deals with a real line of business application. Can someone provide a clear example that illustrates the process of creating a design using TDD?

  Read the article

• SSO between multiple Flex applications

  - by KarthiPk

  We have three applications developed in Flex and all these use BlazeDS. These applications have their own authentication implementations (Database). Also they will be deployed in tomcat. Deploying all these applications in the same tomcat instance is acceptable for us. We want to bring the authentication credentials of all these applications into a single place and also provide SSO feature between these applications. We also want the authentication module to be configurable. Something like the system administrator can decide if the authentication should be done against a database or LDAP. Say, if the user successfully logs into app1, and when he access app2 in the same browser he should be automatically logged in. Same goes for logout as well. We have been exploring OpenAM, jGuard and JOSSO. I'm not sure if these require lot of customization to work with Flex. I would like to know how people are implementing SSO for Flex applications. Is there a common and simple SSO solution available for Flex based applications ?

  Read the article

• Attachment handling for web application with Jackrabbit

  - by Andrea Girardi

  I need to manage attachments on my Spring web application and I thought to use an open source repository. My app it's a job approval system using J2EE / SPRING 3 Framework and Postgress DB to allow user to tracks the job,right through every step of the approval process. It is a fully managed, collaborative system that operates from a central server and is accessed by a standard internet browser. An user should be able to add an attach to a request or an approval step, so, I though to use Jackrabbit with Postgres database persistence manager. I took a look to this post: http://onjava.com/pub/a/onjava/2006/10/04/what-is-java-content-repository.html?page=1 It's really interesting but, I've some question about this kind of solution :- I seen that Jackrabbit standalone as a Derby database embedded solution for persistence, is it enough for a professional use of the repository with more than 50 request / days (with attachment) ? Is there a reason for which I should use another database manager for persistence instead of the default one ?

  Read the article

• What are the most important languages to localize for on the App Store?

  - by Kevin Y

  It's obvious that to gain more customers on any given platform, one of the most important steps to take would be to localize your software into many languages: as many as possible, ideally. However, with independently developed apps, it tends to be difficult to localize into many different languages, due to not having the budget and / or time to do so. My question is if I were to localize my apps into languages other than English on the iOS App Store, which languages should I prioritize? (Maybe the top three or four most important.) (Also, let's pretend this is a generic app that won't cater more to one language demographic than another.)

  Read the article

• usb keyboard stopped working in terminal window after update from 13.04 to 13.10

  - by Jim

  When I start the computer, I am logged in automatically. Using the keyboard, I type Ctrl+Alt+t, which brings up a terminal window, just like it should; however, nothing happens when I attempt to type into the terminal. If I change over to the guest account, I can type into the terminal, but (different problem here, I'll ask it separately unless someone is kind enough to answer it here) my password doesn't work for sudo or anything else. Elsewhere I read that Language support could fix it, but that won't accept my password either - and no, I haven't changed it lately. Also, my Plex Media Server seems to have disappeared. I'll re-install everything if necessary, but I sure would rather avoid that if possible

  Read the article

• What differences should I know? I just upgraded to 13.10 from 10.10 [on hold]

  - by test

  I ran Ubuntu 10.10 for a long time because I liked the menu style. The change in GUI with the upgrades drove me nuts but I finally gave in and downloaded Saucy Salamander 13.10 x64. It's a fresh install running as a virtual machine guest in VMWare Workstation 9 on a Windows 7 x64 host. Well it looks like all those icons are still there on the side which I would be OK with if there were some way to bring back my menus. I have no organized way of accessing things now, or do I? That is the purpose for this question, maybe there is some functionality I just can't find but is there. Also all my fine tuning was gone. I used to be able to change DPI but that's gone. I went ahead and installed Unity Tweak Tool via sudo apt-get install unity-tweak-tool but I couldn't find an icon for it after I installed it.. because again no menu. So I did a search for it and found it there. I've changed the font and which side the window buttons appear on which is good enough for now. Anyway... any suggestions you may have for me I'm game. I'm a Windows 7 user primarily but I use Ubuntu every once in a while. I really liked the old style where everything was categorized like for Applications there was Accessories, Games, Graphics, Internet, Office, Sound & Video, Wine.

  Read the article

• SD card won't appear after upgrade to 13.10

  - by Pixel

  My SD card won't mount when I put it into my lap top, everything was fine before the upgrade. The information about the SD card appears just fine when I type "sudo fdisk l " it just says that it doesn't have a valid partition table. When I type "_sudo blkid" I get the following answer: /dev/sda1: UUID="CCA8-9030" TYPE="vfat" /dev/sda2: UUID="8a1d135b-384b-432d-b608-64dcf09ada24" TYPE="ext2" /dev/sda3: UUID="7s6PtU-kj2Z-N8XD-0mzl-840i-i3HG-enlbAf" TYPE="LVM2_member" /dev/sr0: LABEL="Bamboo CD" TYPE="iso9660" /dev/mapper/ubuntu--vg-root: UUID="c9b521c8-7c9f-493b-95c8-a7d79c465318" TYPE="ext4" /dev/mapper/ubuntu--vg-swap_1: UUID="7f155ab6-e1b9-485b-a2bc-443c0622284d" TYPE="swap" When I use lsusb: Bus 002 Device 002: ID 8087:0024 Intel Corp. Integrated Rate Matching Hub Bus 002 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub Bus 001 Device 003: ID 13d3:5710 IMC Networks UVC VGA Webcam Bus 001 Device 002: ID 8087:0024 Intel Corp. Integrated Rate Matching Hub Bus 001 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub Bus 004 Device 001: ID 1d6b:0003 Linux Foundation 3.0 root hub Bus 003 Device 002: ID 046d:c52f Logitech, Inc. Unifying Receiver Bus 003 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub I've read the other threads and I couldn't really find any good answers, my card reader was compatible with the previous version of ubuntu, so technically it should still be compatible with the next version. Also I can't erase what's on the card, it contains important data which I need... :/ If you need anymore information just ask, I'll give it as soon as I can. Pixel.

  Read the article

• Ubuntu 13.10 Installer freezes on partition recognition on Alienware M17x

  - by Mutewinter

  I'm trying to install Ubuntu 13.10 on an Alienware M17x, after bypassing the graphical problems with "nomodeset" (annoying!), I'm facing a rather different problem: I click on "Install Ubuntu", the guided installation progress reach the point where the partition, mount point etc. needs to be selected and...nothing. In the partition selection menu it sees only dev/sda, but in the window where the actual way the disk is partitioned should appear nothing shows, it's blank. I've tried to click on "change..." to try to force it to read something, but the installer simply quits. The button "change partition table" etcetera are greyed out (well, obviously, since no partition table has been read). What's that? The Alienware has Windows 7 and legacy BIOS (so no UEFI here). Anyone has an idea? Thanks for your time and help!

  Read the article

• can unbuntu 13.03 be loaded with flash drive? USB

  - by Steve Shaw

  I am wanting to do a split pc, half win xp, half unbuntu 13.04, want to use the linux for internet surfing, youtube, crackle, hulu videos viewing. My pc is a older DELL C521, 1.87ghz, 1.5 gb ram, 32bit, 80gb hd...will this be better than present slow slow slow win xp? need it for internet mostly. Would consider dumping win xp later on if I get the hang of the linux distro...any help appreciated. thanks

  Read the article

• Graphics problems: noise-like glitch, and screen freezes in Ubuntu 13.04

  - by user207253

  I have recently upgraded to 13.04 and am using unity. I am experiencing two intermittent problems with the graphics: 1) All or part of the screen is taken up by 'noise', which lasts for about a second, see screenshot: 2) The launcher panel freezes. I can still move the mouse and the keyboard responds to function keys (I can dim the screen), but I cannot select anything. At the moment I recover by ctr-alt-f1, and restarting lightdm. My computer is a Samsung Chronos 7 laptop, model NP700Z5C, with Intel HD 4000 graphics The same problems occur with lightdm and gdm. I have attempted to install the intel drivers (as the screenshot hints) but these are not indicated as additional drivers in software & updates so I'm not sure whether they are in use. Any suggestions?

  Read the article

• What's the lastest version of Openstack that I can deploy with Juju? Where can find this information?

  - by Azendale

  I've been trying to deploy openstack. I thought Havana was the latest, but deployed nova cloud controller, and the log said 2013-10-24 19:13:25 INFO juju juju-log.go:66 nova-cloud-controller/0: FATAL ERROR: Invalid Cloud Archive release specified: precise-updates/havana. Is there somewhere to see what the latest Juju deployable (with the standard repositories) version is? Or am I just using the wrong format when I specify openstack-origin: cloud:precise-updates/havana in the config?

  Read the article

• External hdd boot entries added to GRUB after upgrade to 13.10

  - by Jason

  Long story short, I was using my laptop's internal HDD as an external one on my desktop, and I forgot to remove it when I was upgrading to 13.10. Now GRUB on my desktop has added entries for the Windows and Ubuntu partitions that exist on the laptop's HDD, but I don't want them to be there. Can I safely remove them ? My GRUB table looks like this if I recall correctly: Ubuntu Advanced Options (or something like this) Memtest Another Memtest Entry Windows 7 (loader) on /dev/sda1 Windows 7 (loader) on /dev/sdb1 Ubuntu 13.04 Advanced Options for Ubuntu 13.04 Where Windows 7 (loader) on /dev/sdb1 Ubuntu 13.04 Advanced Options for Ubuntu 13.04 are the entries from the external/laptop's HDD.

  Read the article

• Problem after upgrading to 13.10

  - by paul Barnett

  I am a new user to Ubuntu and not a very accomplished user. I have dual partitioned my laptop, recently upgraded to Windows 8.1 and also Ubuntu 13.10.Now when I boot into Ubuntu I get a running line of 3's and squiggles followed by scrolling (with a fail on the line "reload cups, upon starting avahi-daemon to make sure remote queues are populated"). If I press any key, but mostly return, it will boot into the password page. Any ideas? Thanks.

  Read the article

• Juju didn't configure rabbitmq for openstack?

  - by SaM

  I have installed ubuntu Openstack HA with juju with all 24 servers. But my openstack is not working at all. On dashboard on every page I get errors saying "could not retrieve usage information", "could not retrieve volume information, "could not retrieve .....etc I spent hours and have discovered that juju has not done configuration correctly. I found that on cloud controller in nova.conf juju has added rabitmq vhost enrty, but that virtual host is not added in rabbitmq. Then how is its suppose to work? And on juju-gui canvas rabbimq is all green and is working fine, which in reality its not. I am really wondering if juju has really done correct configuration in all 24 servers now, I am getting the feeling that it would have been faster if I would have done openstack deployment manually instead of using juju. Why was the virtual host entry not added in rabbitmq? How should I solve this?

  Read the article

• System monitor network speed monitor not working for LAN but works for my Wi-fi

  - by Pavak

  I'm on Ubuntu 13.10. I generally use wi-fi to connect to the internet. But Yesterday my wi-fi router occurred some problem and now it's out for warranty. So temporarily I'm using LAN. System monitor displayed the network speed correctly when I was in wi-fi. But now it's not showing any kinda network speed in System Monitor. I checked the preferences opption but couldn't find a way. I also checked "ksysguard"(KDE's system monitor) and conky. None of them working. How can i solve this? I'm attaching a screenshot to clear the problem.

  Read the article

• Can't set music library in Banshee

  - by user1783674

  Recently I noticed that my music doesn't get copied to my music folder when I open files in Banshee and drag them to the library. I opened preferences and the music library folder drop down was empty. I set it back to my music library and tried again: still didn't work. My preferences shows no music folder and I tried setting it to several other folders, neither would stay selected after closing the preferences. What's going on here? Thanks.

  Read the article

• Installing Ubuntu on HP Envy 4 - 1104tx (preinstalled Windows 8)

  - by Froyo

  I have been using Linux for more than 2 years now. I had hp pavilion dv4 laptop and Ubuntu 12.04 was working great. I recently purchased HP Envy 4 - 1104tx which has Windows 8 preinstalled. I tried to install Ubuntu 12.04 but since it is not much compatible with UFEI, I downloaded 64 bit iso of ubuntu 12.10. Made a liveUSB using UnetBootin 583. I followed Installing Ubuntu on a Pre-Installed UEFI Supported Windows 8 system but still I am not able to boot with LiveUSB. I disabled secure boot. There is no option for fast boot or anything as such. It still wouldn't work. I also tried booting through Legacy, but I'm unable to install via LiveUSB. Is there any other way? I don't have SSD so no problem of fake raid. Is there some way by which I can install Ubuntu (12.04 preferred)? I don't care about Windows 8. Is there any way via which I can install Ubutnu over Windows 8? (I don't have a CD/DVD ROM).

  Read the article

• Mouse lagging on 12.10 login page

  - by stariz77

  I just installed ubuntu 12.10 and it seems the mouse lags/is choppy (it will momentarily stick to the page and then appear where I had gestured to instantly every half second or so) on the login page. It appears to go away once my network connection is established. Is this indicative of anything in particular? Do I need to update a driver for something? I have installed it on an OCZ agility 3 SSD, using 8GB ram, intel core i7, intel(R) 82579V Gigabit Network Connection.

  Read the article

< Previous Page | 12 13 14 15 16 17 18  | Next Page >