Search Results

Search found 674 results on 27 pages for 'magical getters setters'.

Page 18/27 | < Previous Page | 14 15 16 17 18 19 20 21 22 23 24 25  | Next Page >

  • Creating a ssh tunnel to transfer files?

    - by Vincent
    For me, networks are a very "opaque" thing, and even with reading a lot of tutorial about SSH, I do not understand how to create a basic tunnel to transfer my files. The configuration is the following : My Computer --[Internet]--> Bridge Machine --[Local Network]--> Final Machine Currently I do the following : 1) Connect to the Bridge Machine with : ssh -X [email protected] 2) Connect to the Final Machine with : ssh -X username@finalmachine 3) I copy the address of files I need (for example .../mydirectory) 4) Then I deconnect from the finalmachine with : exit 5) I copy the files to the bridge : scp -r username@finalmachine:/.../mydirectory . 6) I deconnect from the bridge with : exit 7) I copy the files to my machine : scp -r [email protected]:/.../mydirectory . Which is quite complicated. My question is basic : how to simplify this using a SSH tunnel ? (and please explain me the signification of each command line you write, to understand what each line really do and to avoid to use it like a magical thing. Furthermore if some ports number are used, explain me if I can pick a completely random number or if I have to choose a specific one.)

    Read the article

  • Can I have 2Gbit over 1Gbit Nics

    - by Daniel
    So this really baffles me. Apparently because 1Gbit can transmit data in both directions simultaneously it should be possible to get 2Gbit of data transfer on a single NIC (1Gbit flow seend and 1Gbit receive). People claim that because 1Gbit is full-duplex (almost always) it is exactly 2Gbit in total. My intuition and electrical background tells me that something is not right here 4 twisted pairs 250Mbit capacity each gives 1Gbit. Unless it is really possible to transfer data in both directions simultaneously. I did a test with iperf. Ubuntu server 12.04 <-- MacBook Pro. Both with decent CPU speed. Tested speed of connection individually and on Mac I can see 112MB/s regardless which direction data is going. On Ubuntu with vnstat and ifstat I got 970Mbit speeds. Now, launching iperf in server mode on both machines at the same time and sending data using 2 iperf clients shows that I'm for example on Ubuntu box sending at 600Mbit, and receiving 350Mbit. which adds up to pretty much 1Gbit link. So to me there is no magical 2Gbit. Can someone confirm that or tell why I'm wrong? Another thing that confuses me i the fact that e.g. 24-port switch has for example: Throughput»up»to:»50.6Mpps Switching»capacity:»68Gbps Switch»fabric»speed:»88Gbps Which would suggest thay can handle 2GBit per port.

    Read the article

  • Update Grub on Squeeze - Kernel downgrade due VMware Server

    - by vodoo_boot
    Hi! I happen to run into various problems regarding grub and kernels. I don't really care about the kernel internas. All I want is VMware server in that dedicated root-server. 1.) What is a bzImage vs. vmlinuz? kaze:~# ls /boot/ System.map-2.6.32-5-amd64 bzImage-2.6.33.2 config-2.6.33.2 initrd.img-2.6.32-5-amd64 System.map-2.6.33.2 bzImage-2.6.35.6 config-2.6.35.6 vmlinuz-2.6.32-5-amd64 System.map-2.6.35.6 config-2.6.32-5-amd64 grub I updated my menu.lst (grub2): timeout 5 default 0 fallback 1 title 2.6.32.5 kernel (hd0,1)/boot/vmlinuz-2.6.32-5-amd64 root=/dev/sda2 panic=60 noapic acpi=off title 2.6.35.6 kernel (hd0,1)/boot//bzImage-2.6.35.6 root=/dev/sda2 panic=60 noapic acpi=off title 2.6.32.3 kernel (hd0,1)/boot//bzImage-2.6.33.2 root=/dev/sda2 panic=60 noapic acpi=off That doesn't do well... I think the vmlinuz file is missing initrd or so. Dunno. In fact I don't give too much about kernel boot voodoo as long as it works. update-grub(2) does not work. Does anybody know what magical trick there is to get the 2.6.32-5 booting? 2.) I thought t follow the Deban wiki.. I cannot get header-files for the installed 35.6 or 33.2 kernel in the repositories. I cannot build foreign headers because they will not match the running kernel. So how does one deal with that situtation? I'd prefer not to have to downgrade the kernel. Thanks for any answers!

    Read the article

  • Virtual machines with failover setup

    - by kimmmo
    We have three servers and our plan is to run a number of virtual machines on them in such manner, that if one of the nodes blow up, we can either quickly or seamlessly get a spare running on another node. In addition to the normal networking, they're interconnected via dual 10Gbit NIC's, so networked raid/mirroring shouldn't be a problem. The guest VM's are mostly going to be running text mode linux, but of course it wouldn't hurt to be able to spin up a non-mission critical windows guest for running Visual Studio or checking IE compatibility of a web app. We've spent some time trying to get some magical cloud setup running using Stackops and Crowbar but it started to look like they were offering way too much and were too complicated for our needs. The next candidate, I think, is Ubuntu 11.04 server + KVM + Ganeti + Drbd, unless you can come up with a suggestion for a better solution that we have missed. Requirements: Installation should be simple or at least understandable without being in the dev team A browser interface for creating and managing VM's is a nice bonus Single node's hardware failure should cause minimal downtime for VM's that were running on that node Adding more nodes should be possible without shutting down the VM's.

    Read the article

  • IIS 7.0 - responses throttled to 500ms blocks?

    - by Julia Hayward
    Scenario: ASP.NET MVC wep app sitting on my local machine (Vista Ultimate, IIS 7.0), nothing going on except one user (me) logged in and viewing an index page. The page includes 9 dynamic images drawn from the underlying DB and returned from a controller action. I have got the actual processing time for these images down to 15ms each. Turn on Firebug and watch the page load. What I see is 9 requests for images firing off together – no surprise – but four come back to me almost immediately; two more after 0.5s; another after 1s; then at 1.5s and 2s. Logging on the server side suggests the individual responses are still only taking 15ms. So it appears IIS is queueing things up into 500ms chunks. (Repeating the experiment produces different results, but each time the images return in similar blocks – you might get three in the first group, then three at 0.5s, two at 1s etc, for example – and it’s always at 500ms intervals, not anything else.) It’s also repeatable cross-browser, and it’s not repeatable with other forms of content. I haven't found any particular mention of this problem out there, so I'm sort of assuming it's not an IIS bug, so is it: i) IIS on desktop OSs deliberately does it, to make you use server OSs in production? ii) There is some magical setting that has eluded me for as long as I’ve known IIS? iii) Something peculiar to MVC or SQL Server 2008? or something else?

    Read the article

  • How can I cornify a SharePoint site?

    - by Chris Farmer
    Inspired by the April 1 gravatar changes and the memory of last year's cornification of Stack Overflow, I wanted to add a cornify button to my company's SharePoint app. I just added their html snippet to a Content Editor Web Part. <a href="http://www.cornify.com" onclick="cornify_add();return false;"> <img src="http://www.cornify.com/assets/cornifycorn.gif" width="52" height="51" border="0" alt="Cornify" /> </a><script type="text/javascript" src="http://www.cornify.com/js/cornify.js"></script> The button renders all glittery and beautiful, and the magical functionality works fine in Chrome and Firefox (I'm on Windows 7) for me. But, in IE8, all the gorgeous unicorn images get added at the bottom of the page such that you can't see them unless you scroll down. Since most of our users are IE users, I fear that this just isn't going to be all that much fun. So, is there some known way to force this to work better in IE8, or is there another similarly fun site adornment utility that I could use that might behave better in a SharePoint 2007 app running in IE7/8?

    Read the article

  • Network latency and speed of light

    - by James
    This was kinda of covered by the following Is minimum latency fixed by the speed of light? , but i would like to add the follow up a bit. The scenario is as follows; we have two opposing sites one on the West Coast of the US and one in Ireland. The customer is in central Europe, and has requested a latency test. Ireland gives responses of ~65-70ms. However the West Coast guys claim to be faster with a response of 60ms. Now a quick check says that light in fiber would take about 42ms to make the trip to the States and 8.5ms to Ireland. So obviously this is a single hop and does not include routers, switches, firewalls, protocol overhead etc. Would I be right to call BS on their figures? As a final note I tested a ping to Google IP address that was allegedly on the west coast from a site that covered a similar distance and was amazed to get a response time of 20ms. Suggesting ICMP packets that travel twice the speed of light. So A) what am I missing B) Am I right to suspect shenanigans? UPDATE: Guys thanks so far for your help and I have been reading various previous questions on this. About 5 years I had an issue where the hop from the UK to Ireland added 10ms of latency no matter what we did. In the end I moved the servers; So imagine my surprise when I have guys that claim they are 5ms faster with a transatlantic trip. So again should I call BS? Oh and assume both sites are normal mortals that don't have access to Google magical routing, warp dives or flux capacitors. :)

    Read the article

  • Is execution of sync(8) still required before shutting down linux?

    - by Amos Shapira
    I still see people recommend use of "sync; sync; sync; sleep 30; halt" incantations when talking about shutting down or rebooting Linux. I've been running Linux since its inception and although this was the recommended procedure in the BSD 4.2/4.3 and SunOS 4 days, I can't recall that I had to do that for at least the last ten years, during which I probably went through shutdown/reboot of Linux maybe thousands of times. I suspect that this is an anachronism since the days that the kernel couldn't unmount and sync the root filesystem and other critical filesystems required even during single-user mode (e.g. /tmp), and therefore it was necessary to tell it explicitly to flush as much data as it can to disk. These days, without finding the relevant code in the kernel source yet (digging through http://lxr.linux.no and google), I suspect that the kernel is smart enough to cleanly unmount even the root filesystem and the filesystem is smart enough to effectively do a sync(2) before unmounting itself during a normal "shutdown"/"reboot"/"poweorff". The "sync; sync; sync" is only necessary in extreme cases where the filesystem won't unmount cleanly (e.g. physical disk failure) or the system is in a state that only forcing a direct reboot(8) will get it out of its freeze (e.g. the load is too high to let it schedule the shutdown command). I also never do the "sync" procedure before unmounting removable devices, and never hit a problem. Another example - Xen allows the DomU to be sent a "shutdown" command from the Dom0, this is considered a "clean shutdown" without anyone having to login and type the magical "sync; sync; sync" first. Am I right or was I lucky for a few thousands of system shutdowns?

    Read the article

  • iTunes Home Sharing only works one way between 2 Windows XP PC's on the same LAN

    - by scunliffe
    Both PC's have the latest iTunes installed. PC (A) can "see" that there is a shared library "B library" but attempts to connect to it return this error message: The shared library "{Username}'s Library" is not responding (-3259) Check that any firewall software running on either the shared computer or this computer has been set to allow communication on port 3689. however the reverse works fine. e.g. PC (B) can "see" shared library "A library" and can access all content. Notes: Both PC's have Home Sharing enabled (turned off/on several times to verify). Both PC's have Windows Firewall turned on, but in the exceptions tab, iTunes is allowed, and Port 3689 is also added as a firewall exception (just in case) Both iTunes accounts have been "authorized" on both PC's Both PC's connect via LAN via D-Link DIR-615 router. In the advanced application rules, iTunes has also been added to allow traffic on port 3689 un-hindered. Is there any other magical setting/configuration option that I should be aware of and set in order to get this to work? I could care less about sharing apps etc. I just want the music sharing to work. Update: Solved! It turns out on PC (B) there were multiple accounts set up. 1 of the accounts had the checkbox checked under the Windows firewall "On" option which states "No exceptions" thus even though it was added to the exception list on the main user account, this other account was blocking access.

    Read the article

  • Update Grub on Squeeze - Kernel downgrade due VMware Server

    - by vodoo_boot
    I happen to run into various problems regarding grub and kernels. I don't really care about the kernel internas. All I want is VMware server in that dedicated root-server. 1.) What is a bzImage vs. vmlinuz? kaze:~# ls /boot/ System.map-2.6.32-5-amd64 bzImage-2.6.33.2 config-2.6.33.2 initrd.img-2.6.32-5-amd64 System.map-2.6.33.2 bzImage-2.6.35.6 config-2.6.35.6 vmlinuz-2.6.32-5-amd64 System.map-2.6.35.6 config-2.6.32-5-amd64 grub I updated my menu.lst (grub2): timeout 5 default 0 fallback 1 title 2.6.32.5 kernel (hd0,1)/boot/vmlinuz-2.6.32-5-amd64 root=/dev/sda2 panic=60 noapic acpi=off title 2.6.35.6 kernel (hd0,1)/boot//bzImage-2.6.35.6 root=/dev/sda2 panic=60 noapic acpi=off title 2.6.32.3 kernel (hd0,1)/boot//bzImage-2.6.33.2 root=/dev/sda2 panic=60 noapic acpi=off That doesn't do well... I think the vmlinuz file is missing initrd or so. Dunno. In fact I don't give too much about kernel boot voodoo as long as it works. update-grub(2) does not work. Does anybody know what magical trick there is to get the 2.6.32-5 booting? 2.) I thought t follow the Deban wiki.. I cannot get header-files for the installed 35.6 or 33.2 kernel in the repositories. I cannot build foreign headers because they will not match the running kernel. So how does one deal with that situtation? I'd prefer not to have to downgrade the kernel. Thanks for any answers!

    Read the article

  • Which program is locking all my executable files?

    - by Tom Wijsman
    When updating any software product, as well as manually trying to replace .exe files, it says that access is denied to the file and in fact the System process is holding a handle to the file when I check it with Process Explorer. This must be a driver or something that is malfunctioning was my first though, but now I wonder how I figure out which driver / program is doing this and why it is so. Unlocker doesn't seem to be working for me, unless someone can tell me how to use it properly other than making it appear a magical wand in the notification area.... This is what Unlocker puts in my event log: The description for Event ID 1060 from source Application Popup cannot be found. Either the component that raises this event is not installed on your local computer or the installation is corrupted. You can install or repair the component on the local computer. If the event originated on another computer, the display information had to be saved with the event. The following information was included with the event: \??\C:\Program Files (x86)\Unlocker\UnlockerDriver5.sys the message resource is present but the message is not found in the string/message table Upon searching event 1060 I get: <file name> has been blocked from loading due to incompatibility with this system. Perhaps it is because I have 64 bit?

    Read the article

  • Your interesting code tricks/ conventions? [closed]

    - by Paul
    What interesting conventions, rules, tricks do you use in your code? Preferably some that are not so popular so that the rest of us would find them as novelties. :) Here's some of mine... Input and output parameters This applies to C++ and other languages that have both references and pointers. This is the convention: input parameters are always passed by value or const reference; output parameters are always passed by pointer. This way I'm able to see at a glance, directly from the function call, what parameters might get modified by the function: Inspiration: Old C code int a = 6, b = 7, sum = 0; calculateSum(a, b, &sum); Ordering of headers My typical source file begins like this (see code below). The reason I put the matching header first is because, in case that header is not self-sufficient (I forgot to include some necessary library, or forgot to forward declare some type or function), a compiler error will occur. // Matching header #include "example.h" // Standard libraries #include <string> ... Setter functions Sometimes I find that I need to set multiple properties of an object all at once (like when I just constructed it and I need to initialize it). To reduce the amount of typing and, in some cases, improve readability, I decided to make my setters chainable: Inspiration: Builder pattern class Employee { public: Employee& name(const std::string& name); Employee& salary(double salary); private: std::string name_; double salary_; }; Employee bob; bob.name("William Smith").salary(500.00); Maybe in this particular case it could have been just as well done in the constructor. But for Real WorldTM applications, classes would have lots more fields that should be set to appropriate values and it becomes unmaintainable to do it in the constructor. So what about you? What personal tips and tricks would you like to share?

    Read the article

  • Throwing exception from a property when my object state is invalid

    - by Rumi P.
    Microsoft guidelines say: "Avoid throwing exceptions from property getters", and I normally follow that. But my application uses Linq2SQL, and there is the case where my object can be in invalid state because somebody or something wrote nonsense into the database. Consider this toy example: [Table(Name="Rectangle")] public class Rectangle { [Column(Name="ID", IsPrimaryKey = true, IsDbGenerated = true)] public int ID {get; set;} [Column(Name="firstSide")] public double firstSide {get; set;} [Column(Name="secondSide")] public double secondSide {get; set;} public double sideRatio { get { return firstSide/secondSide; } } } Here, I could write code which ensures that my application never writes a Rectangle with a zero-length side into the database. But no matter how bulletproof I make my own code, somebody could open the database with a different application and create an invalid Rectangle, especially one with a 0 for secondSide. (For this example, please forget that it is possible to design the database in a way such that writing a side length of zero into the rectangle table is impossible; my domain model is very complex and there are constraints on model state which cannot be expressed in a relational database). So, the solution I am gravitating to is to change the getter to: get { if(firstSide > 0 && secondSide > 0) return firstSide/secondSide; else throw new System.InvalidOperationException("All rectangle sides should have a positive length"); } The reasoning behind not throwing exceptions from properties is that programmers should be able to use them without having to make precautions about catching and handling them them. But in this case, I think that it is OK to continue to use this property without such precautions: if the exception is thrown because my application wrote a non-zero rectangle side into the database, then this is a serious bug. It cannot and shouldn't be handled in the application, but there should be code which prevents it. It is good that the exception is visibly thrown, because that way the bug is caught. if the exception is thrown because a different application changed the data in the database, then handling it is outside of the scope of my application. So I can't do anything about it if I catch it. Is this a good enough reasoning to get over the "avoid" part of the guideline and throw the exception? Or should I turn it into a method after all? Note that in the real code, the properties which can have an invalid state feel less like the result of a calculation, so they are "natural" properties, not methods.

    Read the article

  • Minimizing Dependencies For GUIs

    - by tuba09
    I've been working on a project, and have been charged with designing the projects GUI front-end. I'm coding in Java and using the Swing toolkit. Usability-wise, the GUI front-end follows all of Nielsen's heuristics. Users can easily get to where they want to go through the click of a button / JComboBox. Essentially, in Swing terms, what happens is their actions drive the creation/deletion of custom panels. The GUI is coming along fine for the most part. However, I have to admit to being utterly dismayed at the tight web of dependencies my code is being smothered in. The main problem that I've encountered, that I haven't been able to fix as of yet, is how to keep a reference to the panels/buttons being changed. I'll give an example: Say there's a button A Say there's a panel B displaying picture C Say there's another picture D (not currently being displayed by panel B) When user clicks A, panel B should remove picture C and display picture D My question is, what's the best way of keeping track of panel B? Since I need a global point of access to panel B, my solution has so far been to just shoehorn it into a static variable, and access it through a series of static getters and setters. And this static variable is usually stored in the reference's original class. I.e. UserPanel has a static variable that stores a reference to itself. Is there an easy, tried-and-true way of dealing with these kinds of situations? Like my GUI works fine, but it is not modular and/or robust at all. To add to this, the dreaded 'cyclical dependencies' issue that's shunned by so many programmers is out here in full effect. I'm fairly new to development and just want to make sure that my code will be fairly extensible and won't cause much of a headache to the next person that decides to get a try at it. I know there's loads of books out there that probably have a nice elegant solution to this, but unfortunately I just don't have the time to leisure read right now. I need something that's quick and dirty. Thanks in advance

    Read the article

  • Code Coverage for Maven Integrated in NetBeans IDE 7.2

    - by Geertjan
    In NetBeans IDE 7.2, JaCoCo is supported natively, i.e., out of the box, as a code coverage engine for Maven projects, since Cobertura does not work with JDK 7 language constructs. (Although, note that Cobertura is supported as well in NetBeans IDE 7.2.) It isn't part of NetBeans IDE 7.2 Beta, so don't even try there; you need some development build from after that. I downloaded the latest development build today. To enable JaCoCo features in NetBeans IDE, you need do no different to what you'd do when enabling JaCoCo in Maven itself, which is rather wonderful. In both cases, all you need to do is add this to the "plugins" section of your POM: <plugin> <groupId>org.jacoco</groupId> <artifactId>jacoco-maven-plugin</artifactId> <version>0.5.7.201204190339</version> <executions> <execution> <goals> <goal>prepare-agent</goal> </goals> </execution> <execution> <id>report</id> <phase>prepare-package</phase> <goals> <goal>report</goal> </goals> </execution> </executions> </plugin> Now you're done and ready to examine the code coverage of your tests, whether they are JUnit or TestNG. At this point, i.e., for no other reason than that you added the above snippet into your POM, you will have a new Code Coverage menu when you right-click on the project node: If you click Show Report above, the Code Coverage Report window opens. Here, once you've run your tests, you can actually see how many classes have been covered by your tests, which is pretty useful since 100% tests passing doesn't mean much when you've only tested one class, as you can see very graphically below: Then, when you click the bars in the Code Coverage Report window, the class under test is shown, with the methods for which tests exist highlighted in green and those that haven't been covered in red: (Note: Of course, striving for 100% code coverage is a bit nonsensical. For example, writing tests for your getters and setters may not be the most useful way to spend one's time. But being able to measure, and visualize, code coverage is certainly useful regardless of the percentage you're striving to achieve.) Best of all about all this is that everything you see above is available out of the box in NetBeans IDE 7.2. Take a look at what else NetBeans IDE 7.2 brings for the first time to the world of Maven: http://wiki.netbeans.org/NewAndNoteworthyNB72#Maven

    Read the article

  • Styling Windows Phone Silverlight Applications

    - by Tim Murphy
    If you have not developed with styles in Silverlight/XAML then it can be challenging and resources can be sparse depending on how deep you get.  One thing that you need to understand is what level you can apply styles and how much they can cascade.  What I am finding is that this doesn’t go to the level that we are used to in HTML and CSS. While styles can be defined at a page level if you want to share styles throughout your application they should be defined in the App.xaml file.  This is of course analogous to placing a style in your HTML file versus an external CSS file.  This is the type of style I will concentrate on in this post. The first thing to look it how styles associate to elements.  TargetType defines the object type that your style will apply to.  In the example below the style is targeting the TextBlock object type. <Style x:Key="TextBlockSmallGray" TargetType="TextBlock"> Next we use a Setter which allows you to apply values for specific attributes of the target object type.  The setters can be a simple value or complex.  The first example here is simply applying a color to the background property of the target. <Setter Property="Background" Value="White"/> The second setter example here is for the same property, but we are applying a the definition of a LinearGradientBrush. <Setter Property="Background"> <Setter.Value> <LinearGradientBrush> <GradientStop Offset="0" Color="Black"/> <GradientStop Offset="1" Color="White"/> </LinearGradientBrush> </Setter.Value> </Setter> The last thing I want to cover here is that you can leverage the system styles and then override or extend them.  The BasedOn attribute of the Style tag allows this sort of inheritance.  In the example below I am going to start with the PhoneTextTitleStyle and then override properties as needed. <Style x:Key="TextBlockTitle" BasedOn="{StaticResource PhoneTextTitle1Style}" TargetType="TextBlock"> So now that we have our styles defined applying it is fairly straight forward.  Add the style name as a static resource to the style property of the element in your page and off you go. <Grid x:Name="LayoutRoot" Style="{StaticResource PageGridStyle}"> So this is one step in creating consistency in your application’s look.  In future posts I will dig a little deeper. del.icio.us Tags: windows phone 7,mobile development,windows phone 7 development,.NET,software development,design,UX

    Read the article

  • How far should an entity take care of its properties values by itself?

    - by Kharlos Dominguez
    Let's consider the following example of a class, which is an entity that I'm using through Entity Framework. - InvoiceHeader - BilledAmount (property, decimal) - PaidAmount (property, decimal) - Balance (property, decimal) I'm trying to find the best approach to keep Balance updated, based on the values of the two other properties (BilledAmount and PaidAmount). I'm torn between two practices here: Updating the balance amount every time BilledAmount and PaidAmount are updated (through their setters) Having a UpdateBalance() method that the callers would run on the object when appropriate. I am aware that I can just calculate the Balance in its getter. However, it isn't really possible because this is an entity field that needs to be saved back to the database, where it has an actual column, and where the calculated amount should be persisted to. My other worry about the automatically updating approach is that the calculated values might be a little bit different from what was originally saved to the database, due to rounding values (an older version of the software, was using floats, but now decimals). So, loading, let's say 2000 entities from the database could change their status and make the ORM believe that they have changed and be persisted back to the database the next time the SaveChanges() method is called on the context. It would trigger a mass of updates that I am not really interested in, or could cause problems, if the calculation methods changed (the entities fetched would lose their old values to be replaced by freshly recalculated ones, simply by being loaded). Then, let's take the example even further. Each invoice has some related invoice details, which also have BilledAmount, PaidAmount and Balance (I'm simplifying my actual business case for the sake of the example, so let's assume the customer can pay each item of the invoice separately rather than as a whole). If we consider the entity should take care of itself, any change of the child details should cause the Invoice totals to change as well. In a fully automated approach, a simple implementation would be looping through each detail of the invoice to recalculate the header totals, every time one the property changes. It probably would be fine for just a record, but if a lot of entities were fetched at once, it could create a significant overhead, as it would perform this process every time a new invoice detail record is fetched. Possibly worse, if the details are not already loaded, it could cause the ORM to lazy-load them, just to recalculate the balances. So far, I went with the Update() method-way, mainly for the reasons I explained above, but I wonder if it was right. I'm noticing I have to keep calling these methods quite often and at different places in my code and it is potential source of bugs. It also has a detrimental effect on data-binding because when the properties of the detail or header changes, the other properties are left out of date and the method has no way to be called. What is the recommended approach in this case?

    Read the article

  • Architecture or Pattern for handling properties with custom setter/getter?

    - by Shelby115
    Current Situation: I'm doing a simple MVC site for keeping journals as a personal project. My concern is I'm trying to keep the interaction between the pages and the classes simplistic. Where I run into issues is the password field. My setter encrypts the password, so the getter retrieves the encrypted password. public class JournalBook { private IEncryptor _encryptor { get; set; } private String _password { get; set; } public Int32 id { get; set; } public String name { get; set; } public String description { get; set; } public String password { get { return this._password; } set { this.setPassword(this._password, value, value); } } public List<Journal> journals { get; set; } public DateTime created { get; set; } public DateTime lastModified { get; set; } public Boolean passwordProtected { get { return this.password != null && this.password != String.Empty; } } ... } I'm currently using model-binding to submit changes or create new JournalBooks (like below). The problem arises that in the code below book.password is always null, I'm pretty sure this is because of the custom setter. [HttpPost] public ActionResult Create(JournalBook book) { // Create the JournalBook if not null. if (book != null) this.JournalBooks.Add(book); return RedirectToAction("Index"); } Question(s): Should I be handling this not in the property's getter/setter? Is there a pattern or architecture that allows for model-binding or another simple method when properties need to have custom getters/setters to manipulate the data? To summarize, how can I handle the password storing with encryption such that I have the following, Robust architecture I don't store the password as plaintext. Submitting a new or modified JournalBook is as easy as default model-binding (or close to it).

    Read the article

  • Is this a valid implementation of the repository pattern?

    - by user1578653
    I've been reading up about the repository pattern, with a view to implementing it in my own application. Almost all examples I've found on the internet use some kind of existing framework rather than showing how to implement it 'from scratch'. Here's my first thoughts of how I might implement it - I was wondering if anyone could advise me on whether this is correct? I have two tables, named CONTAINERS and BITS. Each CONTAINER can contain any number of BITs. I represent them as two classes: class Container{ private $bits; private $id; //...and a property for each column in the table... public function __construct(){ $this->bits = array(); } public function addBit($bit){ $this->bits[] = $bit; } //...getters and setters... } class Bit{ //some properties, methods etc... } Each class will have a property for each column in its respective table. I then have a couple of 'repositories' which handle things to do with saving/retrieving these objects from the database: //repository to control saving/retrieving Containers from the database class ContainerRepository{ //inject the bit repository for use later public function __construct($bitRepo){ $this->bitRepo = $bitRepo; } public function getById($id){ //talk directly to Oracle here to all column data into the object //get all the bits in the container $bits = $this->bitRepo->getByContainerId($id); foreach($bits as $bit){ $container->addBit($bit); } //return an instance of Container } public function persist($container){ //talk directly to Oracle here to save it to the database //if its ID is NULL, create a new container in database, otherwise update the existing one //use BitRepository to save each of the Bits inside the Container $bitRepo = $this->bitRepo; foreach($container->bits as $bit){ $bitRepo->persist($bit); } } } //repository to control saving/retrieving Bits from the database class BitRepository{ public function getById($id){} public function getByContainerId($containerId){} public function persist($bit){} } Therefore, the code I would use to get an instance of Container from the database would be: $bitRepo = new BitRepository(); $containerRepo = new ContainerRepository($bitRepo); $container = $containerRepo->getById($id); Or to create a new one and save to the database: $bitRepo = new BitRepository(); $containerRepo = new ContainerRepository($bitRepo); $container = new Container(); $container->setSomeProperty(1); $bit = new Bit(); $container->addBit($bit); $containerRepo->persist($container); Can someone advise me as to whether I have implemented this pattern correctly? Thanks!

    Read the article

  • Developer’s Life – Every Developer is a Batman

    - by Pinal Dave
    Batman is one of the darkest superheroes in the fantasy canon.  He does not come to his powers through any sort of magical coincidence or radioactive insect, but through a lot of psychological scarring caused by witnessing the death of his parents.  Despite his dark back story, he possesses a lot of admirable abilities that I feel bear comparison to developers. Batman has the distinct advantage that his alter ego, Bruce Wayne is a millionaire (or billionaire in today’s reboots).  This means that he can spend his time working on his athletic abilities, building a secret lair, and investing his money in cool tools.  This might not be true for developers (well, most developers), but I still think there are many parallels. So how are developers like Batman? Well, read on my list of reasons. Develop Skills Batman works on his skills.  He didn’t get the strength to scale Gotham’s skyscrapers by inheriting his powers or suffering an industrial accident.  Developers also hone their skills daily.  They might not be doing pull-ups and scaling buldings, but I think their skills are just as impressive. Clear Goals Batman is driven to build a better Gotham.  He knows that the criminal who killed his parents was a small-time thief, not a super villain – so he has larger goals in mind than simply chasing one villain.  He wants his city as a whole to be better.  Developers are also driven to make things better.  It can be easy to get hung up on one problem, but in the end it is best to focus on the well-being of the system as a whole. Ultimate Teamplayers Batman is the hero Gotham needs – even when that means appearing to be the bad guys.  Developers probably know that feeling well.  Batman takes the fall for a crime he didn’t commit, and developers often have to deliver bad news about the limitations of their networks and servers.  It’s not always a job filled with glory and thanks, but someone has to do it. Always Ready Batman and the Boy Scouts have this in common – they are always prepared.  Let’s add developers to this list.  Batman has an amazing tool belt with gadgets and gizmos, and let’s not even get into all the functions of the Batmobile!  Developers’ skills might be the knowledge and skills they have developed, not tools they can carry in a utility belt, but that doesn’t make them any less impressive. 100% Dedication Bruce Wayne cultivates the personality of a playboy, never keeping the same girlfriend for long and spending his time partying.  Even though he hides it, his driving force is his deep concern and love for his friends and the city as a whole.  Developers also care a lot about their company and employees – even when it is driving them crazy.  You do your best work when you care about your job on a personal level. Quality Output Batman believes the city deserves to be saved.  The citizens might have a love-hate relationship with both Batman and Bruce Wayne, and employees might not always appreciate developers.  Batman and developers, though, keep working for the best of everyone. I hope you are all enjoying reading about developers-as-superheroes as much as I am enjoying writing about them.  Please tell me how else developers are like Superheroes in the comments – especially if you know any developers who are faster than a speeding bullet and can leap tall buildings in a single bound. Reference: Pinal Dave (http://blog.sqlauthority.com)Filed under: PostADay, SQL, SQL Authority, SQL Query, SQL Server, SQL Tips and Tricks, T SQL Tagged: Developer, Superhero

    Read the article

  • “Query cost (relative to the batch)” <> Query cost relative to batch

    - by Dave Ballantyne
    OK, so that is quite a contradictory title, but unfortunately it is true that a common misconception is that the query with the highest percentage relative to batch is the worst performing.  Simply put, it is a lie, or more accurately we dont understand what these figures mean. Consider the two below simple queries: SELECT * FROM Person.BusinessEntity JOIN Person.BusinessEntityAddress ON Person.BusinessEntity.BusinessEntityID = Person.BusinessEntityAddress.BusinessEntityID go SELECT * FROM Sales.SalesOrderDetail JOIN Sales.SalesOrderHeader ON Sales.SalesOrderDetail.SalesOrderID = Sales.SalesOrderHeader.SalesOrderID After executing these and looking at the plans, I see this : So, a 13% / 87% split ,  but 13% / 87% of WHAT ? CPU ? Duration ? Reads ? Writes ? or some magical weighted algorithm ?  In a Profiler trace of the two we can find the metrics we are interested in. CPU and duration are well out but what about reads (210 and 1935)? To save you doing the maths, though you are more than welcome to, that’s a 90.2% / 9.8% split.  Close, but no cigar. Lets try a different tact.  Looking at the execution plan the “Estimated Subtree cost” of query 1 is 0.29449 and query 2 its 1.96596.  Again to save you the maths that works out to 13.03% and 86.97%, round those and thats the figures we are after.  But, what is the worrying word there ? “Estimated”.  So these are not “actual”  execution costs,  but what’s the problem in comparing the estimated costs to derive a meaning of “Most Costly”.  Well, in the case of simple queries such as the above , probably not a lot.  In more complicated queries , a fair bit. By modifying the second query to also show the total number of lines on each order SELECT *,COUNT(*) OVER (PARTITION BY Sales.SalesOrderDetail.SalesOrderID) FROM Sales.SalesOrderDetail JOIN Sales.SalesOrderHeader ON Sales.SalesOrderDetail.SalesOrderID = Sales.SalesOrderHeader.SalesOrderID The split in percentages is now 6% / 94% and the profiler metrics are : Even more of a discrepancy. Estimates can be out with actuals for a whole host of reasons,  scalar UDF’s are a particular bug bear of mine and in-fact the cost of a udf call is entirely hidden inside the execution plan.  It always estimates to 0 (well, a very small number). Take for instance the following udf Create Function dbo.udfSumSalesForCustomer(@CustomerId integer) returns money as begin Declare @Sum money Select @Sum= SUM(SalesOrderHeader.TotalDue) from Sales.SalesOrderHeader where CustomerID = @CustomerId return @Sum end If we have two statements , one that fires the udf and another that doesn't: Select CustomerID from Sales.Customer order by CustomerID go Select CustomerID,dbo.udfSumSalesForCustomer(Customer.CustomerID) from Sales.Customer order by CustomerID The costs relative to batch is a 50/50 split, but the has to be an actual cost of firing the udf. Indeed profiler shows us : No where even remotely near 50/50!!!! Moving forward to window framing functionality in SQL Server 2012 the optimizer sees ROWS and RANGE ( see here for their functional differences) as the same ‘cost’ too SELECT SalesOrderDetailID,SalesOrderId, SUM(LineTotal) OVER(PARTITION BY salesorderid ORDER BY Salesorderdetailid RANGE unbounded preceding) from Sales.SalesOrderdetail go SELECT SalesOrderDetailID,SalesOrderId, SUM(LineTotal) OVER(PARTITION BY salesorderid ORDER BY Salesorderdetailid Rows unbounded preceding) from Sales.SalesOrderdetail By now it wont be a great display to show you the Profiler trace reads a *tiny* bit different. So moral of the story, Percentage relative to batch can give a rough ‘finger in the air’ measurement, but dont rely on it as fact.

    Read the article

  • Drupal Modules for SEO & Content

    - by Aditi
    When we talk about Drupal SEO, there are two things to consider one is about the relevant SEO practices and about appropriate Drupal Modules available. Optimizing your website for search engines is one of the most important aspect of launching & promoting your website especially if ranking matters to you. Understanding SEO For starters, you have begin with Keyword research and then optimize your content according to your findings by tagging, meta tags etc, Drupal modules once installed help you manage a lot of such parameters. Identifying the target keywords Using the Page Title and Token modules PathAuto configuration <H1> heading tags Optimizing Drupal’s default robots.txt file Etc. While Drupal gives you a lot of ability to make your website content worthy & search engine friendly it is important for you to make sure you are not crossing the line or you could get penalized. Modules Overview Drupal Power is at its best when you have these modules & great brain working together. The basic SEO improvements can be achieved easily with the modules enlisted below, but you can win magical rankings if you use them logically & wisely. Understanding your keyword competition & enhancing your content is the basic key to success and ofcourse the modules: Pathauto Automatically create search enging friendly readable URLS from tokens. A token is a piece of data from content, say the author’s username, or the content’s title. For example mysite.com/an-article, rather than mysite.com/node/114 for every node you make. NodeWords Amazingly useful drupal module that allows you to create custom meta tags and descriptions for your nodes, which gives you the ability to target specific keywords and phrases. Page Title Enables you to set an alternative title for the <title></title> tags and for the <h1></h1> tags on a node. Global Redirect Manage content duplication, 301 redirects, and URL validation with this small, but powerful module. Taxonomy manager Make large additions, or changes to taxonomy very easy. This module provides a powerful interface for managing taxonomies. A vocabulary gets displayed in a dynamic tree view, where parent terms can be expanded to list their nested child terms or can be collapsed. robotstxt A robots.txt file is vital for ensuring that search engine spiders don’t index the unwanted areas of your site. This Drupal module gives you the ability to manage your robots.txt file through the CMS admin. xmlsitemap An XML Sitemap lets the search engines index your website content. This module helps in generating and maintaining a complete sitemap for your website and gives you control over exactly which parts of the site you want to be included in the index. It even gives you the ability to automatically submit your sitemap to Google, Yahoo!, Ask.com and Windows Live every time you update a node or at specific interval. Node Import This module allows you to import a set of nodes from a Comma Seperated Values (CSV) or Tab Seperated Values (TSV) text file. Makes it easy to import hundreds-thousands of csv rows and you get to tie up these rows to CCK fields (or locations), and it can file it under the right taxonomy hierarchy. This is Super life saver module.

    Read the article

  • How do NTP Servers Manage to Stay so Accurate?

    - by Akemi Iwaya
    Many of us have had the occasional problem with our computers and other devices retaining accurate time settings, but a quick sync with an NTP server makes all well again. But if our own devices can lose accuracy, how do NTP servers manage to stay so accurate? Today’s Question & Answer session comes to us courtesy of SuperUser—a subdivision of Stack Exchange, a community-driven grouping of Q&A web sites. Photo courtesy of LEOL30 (Flickr). The Question SuperUser reader Frank Thornton wants to know how NTP servers are able to remain so accurate: I have noticed that on my servers and other machines, the clocks always drift so that they have to sync up to remain accurate. How do the NTP server clocks keep from drifting and always remain so accurate? How do the NTP servers manage to remain so accurate? The Answer SuperUser contributor Michael Kjorling has the answer for us: NTP servers rely on highly accurate clocks for precision timekeeping. A common time source for central NTP servers are atomic clocks, or GPS receivers (remember that GPS satellites have atomic clocks onboard). These clocks are defined as accurate since they provide a highly exact time reference. There is nothing magical about GPS or atomic clocks that make them tell you exactly what time it is. Because of how atomic clocks work, they are simply very good at, having once been told what time it is, keeping accurate time (since the second is defined in terms of atomic effects). In fact, it is worth noting that GPS time is distinct from the UTC that we are more used to seeing. These atomic clocks are in turn synchronized against International Atomic Time or TAI in order to not only accurately tell the passage of time, but also the time. Once you have an exact time on one system connected to a network like the Internet, it is a matter of protocol engineering enabling transfer of precise times between hosts over an unreliable network. In this regard a Stratum 2 (or farther from the actual time source) NTP server is no different from your desktop system syncing against a set of NTP servers. By the time you have a few accurate times (as obtained from NTP servers or elsewhere) and know the rate of advancement of your local clock (which is easy to determine), you can calculate your local clock’s drift rate relative to the “believed accurate” passage of time. Once locked in, this value can then be used to continuously adjust the local clock to make it report values very close to the accurate passage of time, even if the local real-time clock itself is highly inaccurate. As long as your local clock is not highly erratic, this should allow keeping accurate time for some time even if your upstream time source becomes unavailable for any reason. Some NTP client implementations (probably most ntpd daemon or system service implementations) do this, and others (like ntpd’s companion ntpdate which simply sets the clock once) do not. This is commonly referred to as a drift file because it persistently stores a measure of clock drift, but strictly speaking it does not have to be stored as a specific file on disk. In NTP, Stratum 0 is by definition an accurate time source. Stratum 1 is a system that uses a Stratum 0 time source as its time source (and is thus slightly less accurate than the Stratum 0 time source). Stratum 2 again is slightly less accurate than Stratum 1 because it is syncing its time against the Stratum 1 source and so on. In practice, this loss of accuracy is so small that it is completely negligible in all but the most extreme of cases. Have something to add to the explanation? Sound off in the comments. Want to read more answers from other tech-savvy Stack Exchange users? Check out the full discussion thread here.

    Read the article

  • asynchrony is viral

    - by Daniel Moth
    It is becoming hard to write code today without introducing some form of asynchrony and, if you are using .NET (e.g. for Windows Phone 8 or Windows Store apps), that means sooner or later you have to await something and mark your method as async. My most recent examples included introducing speech recognition in my Translator By Moth phone app where I had to await mySpeechRecognizerUI.RecognizeWithUIAsync() and when moving that code base to a Windows Store project just to show a MessageBox I had to await myMessageDialog.ShowAsync(). Any time you need to invoke an asynchronous method in your code, you have a choice to make: kick off the operation but don’t wait for it to complete (otherwise known as fire-and-forget), synchronously wait for it to complete (which will entail blocking, which can be bad, especially on a UI thread), or asynchronously wait for it to complete before continuing on with the rest of the method’s work. In most cases, you want the latter, and the await keyword makes that trivial to implement.  When you use the magical await keyword in front of an API call, then you typically have to make additional changes to your code: This await usage is within a method of course, and now you have to annotate that method with async. Furthermore, you have to change the return type of the method you just annotated so it returns a Task (if it previously returned void), or Task<myOldReturnType> (if it previously returned myOldReturnType). Note that if it returns void, in some cases you could cheat and stop there. Furthermore, any method that called this method you just annotated with async will now also be invoking an asynchronous operation, so you have to make that change in the body of the caller method to introduce the await keyword before the call to the method. …you guessed it, you now have to change this caller method to be annotated with async and have its return types tweaked... …and it goes on virally… At some point you reach the root of your user code, e.g. a GUI event handler, and whoever calls that void method can already deal with the fact that you marked it as async and the viral introduction of the keywords stops there… This is all wonderful progress and a very powerful mechanism, and I just wish someone had written a refactoring tool to take care of this… anyone? I mentioned earlier that you have a choice when invoking an asynchronous operation. If the first time you encounter this you wish to localize the impact of all these changes and essentially try to turn the asynchronous behavior into synchronous by blocking - don't! For reasons why you don't want to do that, read Toub's excellent blog post (and check out the rest of his blog with gems on async programming starting with the Async FAQ). Just embrace the pattern knowing that when you use one instance of an await, you'll propagate the change all the way to the root user code method, e.g. typically an event handler. Related aside: I just finished re-writing my MessageBox wrapper class for Phone projects, including making it work in Windows Store projects, and it does expect you to use it with an await :-). I'll share that in an upcoming post for those of you that have the same need… Comments about this post by Daniel Moth welcome at the original blog.

    Read the article

  • Big Data: Size isn’t everything

    - by Simon Elliston Ball
    Big Data has a big problem; it’s the word “Big”. These days, a quick Google search will uncover terabytes of negative opinion about the futility of relying on huge volumes of data to produce magical, meaningful insight. There are also many clichéd but correct assertions about the difficulties of correlation versus causation, in massive data sets. In reading some of these pieces, I begin to understand how climatologists must feel when people complain ironically about “global warming” during snowfall. Big Data has a name problem. There is a lot more to it than size. Shape, Speed, and…err…Veracity are also key elements (now I understand why Gartner and the gang went with V’s instead of S’s). The need to handle data of different shapes (Variety) is not new. Data developers have always had to mold strange-shaped data into our reporting systems, integrating with semi-structured sources, and even straying into full-text searching. However, what we lacked was an easy way to add semi-structured and unstructured data to our arsenal. New “Big Data” tools such as MongoDB, and other NoSQL (Not Only SQL) databases, or a graph database like Neo4J, fill this gap. Still, to many, they simply introduce noise to the clean signal that is their sensibly normalized data structures. What about speed (Velocity)? It’s not just high frequency trading that generates data faster than a single system can handle. Many other applications need to make trade-offs that traditional databases won’t, in order to cope with high data insert speeds, or to extract quickly the required information from data streams. Unfortunately, many people equate Big Data with the Hadoop platform, whose batch driven queries and job processing queues have little to do with “velocity”. StreamInsight, Esper and Tibco BusinessEvents are examples of Big Data tools designed to handle high-velocity data streams. Again, the name doesn’t do the discipline of Big Data any favors. Ultimately, though, does analyzing fast moving data produce insights as useful as the ones we get through a more considered approach, enabled by traditional BI? Finally, we have Veracity and Value. In many ways, these additions to the classic Volume, Velocity and Variety trio acknowledge the criticism that without high-quality data and genuinely valuable outputs then data, big or otherwise, is worthless. As a discipline, Big Data has recognized this, and data quality and cleaning tools are starting to appear to support it. Rather than simply decrying the irrelevance of Volume, we need as a profession to focus how to improve Veracity and Value. Perhaps we should just declare the ‘Big’ silent, embrace these new data tools and help develop better practices for their use, just as we did the good old RDBMS? What does Big Data mean to you? Which V gives your business the most pain, or the most value? Do you see these new tools as a useful addition to the BI toolbox, or are they just enabling a dangerous trend to find ghosts in the noise?

    Read the article

< Previous Page | 14 15 16 17 18 19 20 21 22 23 24 25  | Next Page >