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• T4MVC Optional Parameter Inferred From Current Context

  - by Itakou

  I have read the other post about this at T4MVC OptionalParameter values implied from current context and I am using the latest T4MVC (2.11.1) which is suppose to have the fix in. I even checked checked to make sure that it's there -- and it is. I am still getting the optional parameters filled in based on the current context. For example: Let's say I have a list that is by default ordered by a person's last name. I have the option to order by first name instead with the URL http://localhost/list/stuff?orderby=firstname When I am in that page, I want to go back to order by first name with the code: @Html.ActionLink("order by last name", MVC.List.Stuff(null)) the link I wanted was simply http://localhost/list/stuff without any parameters to keep the URL simple and short - invoking default behaviors within the action. But instead the orderby is kept and the url is still http://localhost/list/stuff?orderby=firstname Any help would be great. I know that in the most general cases, this does remove the query parameter - maybe I do have a specific case where it was not removed. I find that it only happens when I have the URL inside a page that I included with RenderPartial. My actual code is <li>@Html.ActionLink("Recently Updated", MVC.Network.Ticket.List(Model.UI.AccountId, "LastModifiedDate", null, null, null, null, null))</li> <li>@Html.ActionLink("Recently Created", MVC.Network.Ticket.List(Model.UI.AccountId, "CreatedDate", null, null, null, null, null))</li> <li>@Html.ActionLink("Most Severe", MVC.Network.Ticket.List(Model.UI.AccountId, "MostSevere", null, null, null, null, null))</li> <li>@Html.ActionLink("Previously Closed", MVC.Network.Ticket.List(Model.UI.AccountId, "LastModifiedDate", null, "Closed", null, null, null))</li> the problem happens when someone clicks Previously Closed and and go to ?status=closed. When they click Recently Updated, which I want to the ?status so that it shows the active ones, the ?status=closed stays. Any insight would be greatly appreciated.

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• Noise with multi-threaded raytracer

  - by herber88

  This is my first multi-threaded implementation, so it's probably a beginners mistake. The threads handle the rendering of every second row of pixels (so all rendering is handled within each thread). The problem persists if the threads render the upper and lower parts of the screen respectively. Both threads read from the same variables, can this cause any problems? From what I've understood only writing can cause concurrency problems... Can calling the same functions cause any concurrency problems? And again, from what I've understood this shouldn't be a problem... The only time both threads write to the same variable is when saving the calculated pixel color. This is stored in an array, but they never write to the same indices in that array. Can this cause a problem? Multi-threaded rendered image (Spam prevention stops me from posting images directly..) Ps. I use the exactly same implementation in both cases, the ONLY difference is a single vs. two threads created for the rendering.

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• Is it true that in most Object Oriented Programming Languages, an "i" in an instance method always r

  - by Jian Lin

  In the following code: <script type="text/javascript"> var i = 10; function Circle(radius) { this.r = radius; this.i = radius; } Circle.i = 123; Circle.prototype.area = function() { alert(i); } var c = new Circle(1); var a = c.area(); </script> What is being alerted? The answer is at the end of this question. I found that the i in the alert call either refers to any local (if any), or the global variable. There is no way that it can be the instance variable or the class variable even when there is no local and no global defined. To refer to the instance variable i, we need this.i, and to the class variable i, we need Circle.i. Is this actually true for almost all Object oriented programming languages? Any exception? Are there cases that when there is no local and no global, it will look up the instance variable and then the class variable scope? (or in this case, are those called scope?) the answer is: 10 is being alerted.

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• help me to choose between two designs

  - by alex

  // stupid title, but I could not think anything smarter I have a code (see below, sorry for long code but it's very-very simple): namespace Option1 { class AuxClass1 { string _field1; public string Field1 { get { return _field1; } set { _field1 = value; } } // another fields. maybe many fields maybe several properties public void Method1() { // some action } public void Method2() { // some action 2 } } class MainClass { AuxClass1 _auxClass; public AuxClass1 AuxClass { get { return _auxClass; } set { _auxClass = value; } } public MainClass() { _auxClass = new AuxClass1(); } } } namespace Option2 { class AuxClass1 { string _field1; public string Field1 { get { return _field1; } set { _field1 = value; } } // another fields. maybe many fields maybe several properties public void Method1() { // some action } public void Method2() { // some action 2 } } class MainClass { AuxClass1 _auxClass; public string Field1 { get { return _auxClass.Field1; } set { _auxClass.Field1 = value; } } public void Method1() { _auxClass.Method1(); } public void Method2() { _auxClass.Method2(); } public MainClass() { _auxClass = new AuxClass1(); } } } class Program { static void Main(string[] args) { // Option1 Option1.MainClass mainClass1 = new Option1.MainClass(); mainClass1.AuxClass.Field1 = "string1"; mainClass1.AuxClass.Method1(); mainClass1.AuxClass.Method2(); // Option2 Option2.MainClass mainClass2 = new Option2.MainClass(); mainClass2.Field1 = "string2"; mainClass2.Method1(); mainClass2.Method2(); Console.ReadKey(); } } What option (option1 or option2) do you prefer ? In which cases should I use option1 or option2 ? Is there any special name for option1 or option2 (composition, aggregation) ?

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• Unit Testing - Algorithm or Sample based ?

  - by ohadsc

  Say I'm trying to test a simple Set class public IntSet : IEnumerable<int> { Add(int i) {...} //IEnumerable implementation... } And suppose I'm trying to test that no duplicate values can exist in the set. My first option is to insert some sample data into the set, and test for duplicates using my knowledge of the data I used, for example: //OPTION 1 void InsertDuplicateValues_OnlyOneInstancePerValueShouldBeInTheSet() { var set = new IntSet(); //3 will be added 3 times var values = new List<int> {1, 2, 3, 3, 3, 4, 5}; foreach (int i in values) set.Add(i); //I know 3 is the only candidate to appear multiple times int counter = 0; foreach (int i in set) if (i == 3) counter++; Assert.AreEqual(1, counter); } My second option is to test for my condition generically: //OPTION 2 void InsertDuplicateValues_OnlyOneInstancePerValueShouldBeInTheSet() { var set = new IntSet(); //The following could even be a list of random numbers with a duplicate var values = new List<int> { 1, 2, 3, 3, 3, 4, 5}; foreach (int i in values) set.Add(i); //I am not using my prior knowledge of the sample data //the following line would work for any data CollectionAssert.AreEquivalent(new HashSet<int>(values), set); } Of course, in this example, I conveniently have a set implementation to check against, as well as code to compare collections (CollectionAssert). But what if I didn't have either ? This is the situation when you are testing your real life custom business logic. Granted, testing for expected conditions generically covers more cases - but it becomes very similar to implementing the logic again (which is both tedious and useless - you can't use the same code to check itself!). Basically I'm asking whether my tests should look like "insert 1, 2, 3 then check something about 3" or "insert 1, 2, 3 and check for something in general" EDIT - To help me understand, please state in your answer if you prefer OPTION 1 or OPTION 2 (or neither, or that it depends on the case, etc )

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• best web database solution for scala for a high traffic site?

  - by egervari

  I am in charge of a rebuilding a website that gets about 250,000 visitors a day. We'd like to use Scala, but it does not work very well with Spring (in some minor cases) and Hibernate (there is a major and very annoying mismatch here if you want to use scala collections, which we do). The application itself is going to have about 40-50 tables. Other than Hibernate, is there an ORM that works awesome with Scala and is as performant and reliable as Hibernate? Does it also have the same capabilities, or are we going to run into leaky-abstractions if we don't use Hibernate? It would be a big risk for us to go with a framework that is newer and doesn't seem to have a lot of industry backing... and at the same time, Hibernate is a real pain to program against when using Scala. 1) The Java Collection <- Scala Collection is absolutely painful. There is a lot more boilerplate and crap to write. 2) The IDE doesn't import JavaConversions and java interfaces automatically... so we this needs to be done manually. Optimizing Imports in IDEA is going to destroy all the manual work. 3) There is also a performance cost to converting back and forth all the time in your domain objects and your dao classes. 4) Not to mention there needs to be a lot of casting, which produces code ugly as sin. I actually would love to write my own orm that is 100% tailored to scala, but obviously this is really outside of the scope of our project for now. So what is the best approach?

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• When is a bool not a bool (compiler warning C4800)

  - by omatai

  Consider this being compiled in MS Visual Studio 2005 (and probably others): CPoint point1( 1, 2 ); CPoint point2( 3, 4 ); const bool point1And2Identical( point1 == point2 ); // C4800 warning const bool point1And2TheSame( ( point1 == point2 ) == TRUE ); // no warning What the...? Is the MSVC compiler brain-dead? As far as I can tell, TRUE is #defined as 1, without any type information. So by what magic is there any difference between these two lines? Surely the type of the expression inside the brackets is the same in both cases? [This part of the question now satisfactorily answered in the comments just below] Personally, I think that avoiding the warning by using the == TRUE option is ugly (though less ugly than the != 0 alternative, despite being more strictly correct), and it is better to use #pragma warning( disable:4800 ) to imply "my code is good, the compiler is an ass". Agree? Note - I have seen all manner of discussion on C4800 talking about assigning ints to bools, or casting a burger combo with large fries (hold the onions) to a bool, and wondering why there are strange results. I can't find a clear answer on what seems like a much simpler question... that might just shine line on C4800 in general.

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• BufferedImage & ColorModel in Java

  - by spol

  I am using a image processing library in java to manipulate images.The first step I do is I read an image and create a java.awt.Image.BufferedImage object. I do it in this way, BufferedImage sourceImage = ImageIO.read( new File( filePath ) ); The above code creates a BufferedImage ojbect with a DirectColorModel: rmask=ff0000 gmask=ff00 bmask=ff amask=0. This is what happens when I run the above code on my macbook. But when I run this same code on a linux machine (hosted server), this creates a BufferedImage object with ColorModel: #pixelBits = 24 numComponents = 3 color space = java.awt.color.ICC_ColorSpace@c39a20 transparency = 1 has alpha = false isAlphaPre = false. And I use the same jpg image in both the cases. I don't know why the color model on the same image is different when run on mac and linux. The colormodel for mac has 4 components and the colormodel for linux has 3 components.There is a problem arising because of this, the image processing library that I use always assumes that there are always 4 components in the colormodel of the image passed, and it throws array out of bounds exception when run on linux box. But on macbook, it runs fine. I am not sure if I am doing something wrong or there is a problem with the library. Please let me know your thoughts. Also ask me any questions if I am not making sense!

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• Extended slice that goes to beginning of sequence with negative stride

  - by recursive

  Bear with me while I explain my question. Skip down to the bold heading if you already understand extended slice list indexing. In python, you can index lists using slice notation. Here's an example: >>> A = list(range(10)) >>> A[0:5] [0, 1, 2, 3, 4] You can also include a stride, which acts like a "step": >>> A[0:5:2] [0, 2, 4] The stride is also allowed to be negative, meaning the elements are retrieved in reverse order: >>> A[5:0:-1] [5, 4, 3, 2, 1] But wait! I wanted to see [4, 3, 2, 1, 0]. Oh, I see, I need to decrement the start and end indices: >>> A[4:-1:-1] [] What happened? It's interpreting -1 as being at the end of the array, not the beginning. I know you can achieve this as follows: >>> A[4::-1] [4, 3, 2, 1, 0] But you can't use this in all cases. For example, in a method that's been passed indices. My question is: Is there any good pythonic way of using extended slices with negative strides and explicit start and end indices that include the first element of a sequence? This is what I've come up with so far, but it seems unsatisfying. >>> A[0:5][::-1] [4, 3, 2, 1, 0]

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• How to model and handle presentation DTO's to abstract from complicated domain model?

  - by arrages

  Hi I am developing an application that needs to work with a complex domain model using Hibernate. This application uses Spring MVC and using the domain objects in the presentation layer is very messy so I think I should use DTO's that go to and from my service layer so that these match what I need in my views. Now lets assume I have a CarLease entity whose properties are not simple java primitives but it's composed with other entities like Make, Model, etc public class CarLease { private Make make; Private Model model; . . . } most properties are in this fashion and they are selectable using drop down selects on the jsp view, each will post back an ID to the controller. Now considering some standard use cases: create, edit, display How would you go about modeling the presentation DTO's to be used as form backing objects and communication between presentation and service layers?? Would you create a different DTO for each case (create, edit, display), would you make DTO's for the complex attributes? if so where would you translate the ID to entity? how and where would you handle validation, DTO/Domain assembly, what would you return from service layer methods? (create, edit, get) As you can see, I now I will benefit by separating my view from the domain objects (very complex with lots of stuff I don't need.) but I am having a hard time finding any real world examples and best practices for this. I need some architecture guidance from top to bottom, please keep in mind I will use Spring MVC in case that may leverage on your anwser. thanks in advance.

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• Modular Inverse and BigInteger division

  - by dano82

  I've been working on the problem of calculating the modular inverse of an large integer i.e. a^-1 mod n. and have been using BigInteger's built in function modInverse to check my work. I've coded the algorithm as shown in The Handbook of Applied Cryptography by Menezes, et al. Unfortunately for me, I do not get the correct outcome for all integers. My thinking is that the line q = a.divide(b) is my problem as the divide function is not well documented (IMO)(my code suffers similarly). Does BigInteger.divide(val) round or truncate? My assumption is truncation since the docs say that it mimics int's behavior. Any other insights are appreciated. This is the code that I have been working with: private static BigInteger modInverse(BigInteger a, BigInteger b) throws ArithmeticException { //make sure a >= b if (a.compareTo(b) < 0) { BigInteger temp = a; a = b; b = temp; } //trivial case: b = 0 => a^-1 = 1 if (b.equals(BigInteger.ZERO)) { return BigInteger.ONE; } //all other cases BigInteger x2 = BigInteger.ONE; BigInteger x1 = BigInteger.ZERO; BigInteger y2 = BigInteger.ZERO; BigInteger y1 = BigInteger.ONE; BigInteger x, y, q, r; while (b.compareTo(BigInteger.ZERO) == 1) { q = a.divide(b); r = a.subtract(q.multiply(b)); x = x2.subtract(q.multiply(x1)); y = y2.subtract(q.multiply(y1)); a = b; b = r; x2 = x1; x1 = x; y2 = y1; y1 = y; } if (!a.equals(BigInteger.ONE)) throw new ArithmeticException("a and n are not coprime"); return x2; }

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• Iphone Core Data Internal Inconsistency

  - by kiyoshi

  This question has something to do with the question I posted here: http://stackoverflow.com/questions/1230858/iphone-core-data-crashing-on-save however the error is different so I am making a new question. Now I get this error when trying to insert new objects into my managedObjectContext: *** Terminating app due to uncaught exception 'NSInternalInconsistencyException', reason: '"MailMessage" is not a subclass of NSManagedObject.' But clearly it is: @interface MailMessage : NSManagedObject { .... And when I run this code: NSManagedObjectModel *managedObjectModel = [[self.managedObjectContext persistentStoreCoordinator] managedObjectModel]; NSEntityDescription *entity =[[managedObjectModel entitiesByName] objectForKey:@"MailMessage"]; NSManagedObject *newObject = [[NSManagedObject alloc] initWithEntity:entity insertIntoManagedObjectContext:self.managedObjectContext]; It runs fine when I do not present an MFMailComposeViewController, but if I run this code in the - (void)mailComposeController:(MFMailComposeViewController*)controller didFinishWithResult:(MFMailComposeResult)result error:(NSError*)error { method, it throws the above error when creating the newObject variable. The entity object when I use print object produces the following: (<NSEntityDescription: 0x1202e0>) name MailMessage, managedObjectClassName MailMessage, renamingIdentifier MailMessage, isAbstract 0, superentity name (null), properties { in both cases, so I don't think the managedObjectContext is completely invalid. I have no idea why it would say MailMessage is not a subclass of NSManagedObject at that point, and not at the other. Any help would be appreciated, thanks in advance.

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• Which options do I have for Java process communication?

  - by Dmitriy Matveev

  We have a place in a code of such form: void processParam(Object param) { wrapperForComplexNativeObject result = jniCallWhichMayCrash(param); processResult(result); } processParam - method which is called with many different arguments. jniCallWhichMayCrash - a native method which is intended to do some complex processing of it's parameter and to create some complex object. It can crash in some cases. wrapperForComplexNativeObject - wrapper type generated by SWIG processResult - a method written in pure Java which processes it's parameter by creation of several kinds (by the kinds I'm not meaning classes, maybe some like hierarchies) of objects: 1 - Some non-unique objects which are referencing each other (from the same hierarchy), these objects can have duplicates created from the invocations of processParam() method with different parameter values. Since it's costly to keep all the duplicates it's necessary to cache them. 2 - Some unique objects which are referencing each other (from the same hierarchy) and some of the objects of 1st kind. After processParam is executed for each of the arguments from some set the data created in processResult will be processed together. The problem is in fact that jniCallWhichMayCrash method may crash the entire JVM and this will be very bad. The reason of crash may be such that it can happen for one argument value and not for the other. We've decided that it's better to ignore crashes inside of JVM and just skip some chunks of data when such crashes occur. In order to do this we should run processParam function inside of separate process and pass the result somehow (HOW? HOW?! This is a question) to the main process and in case of any crashes we will only lose some part of data (It's ok) without lose of everything else. So for now the main problem is implementation of transport between different processes. Which options do I have? I can think about serialization and transmitting of binary data by the streams, but serialization may be not very fast due to object complexity. Maybe I have some other options of implementing this?

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• C++ and Dependency Injection in unit testing

  - by lhumongous

  Suppose I have a C++ class like so: class A { public: A() { } void SetNewB( const B& _b ) { m_B = _b; } private: B m_B; } In order to unit test something like this, I would have to break A's dependency on B. Since class A holds onto an actual object and not a pointer, I would have to refactor this code to take a pointer. Additionally, I would need to create a parent interface class for B so I can pass in my own fake of B when I test SetNewB. In this case, doesn't unit testing with dependency injection further complicate the existing code? If I make B a pointer, I'm now introducing heap allocation, and some piece of code is now responsible for cleaning it up (unless I use ref counted pointers). Additionally, if B is a rather trivial class with only a couple of member variables and functions, why introduce a whole new interface for it instead of just testing with an instance of B? I suppose you could make the argument that it would be easier to refactor A by using an interface. But are there some cases where two classes might need to be tightly coupled?

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• C# Casting system.__comobject to class type

  - by ijrufus

  I have an Excel Add-In that I'm currently trying to set up a unit test framework for. For the unit tests I've followed this guide: http://blogs.msdn.com/b/varsha/archive/2010/08/17/writing-automated-test-cases-for-vsto-application.aspx It seems to work fine, until I want to return a class object from my interface. Specifying the class object as the return type throws a "return argument has an invalid type" exception when calling the method. Changing the return type from the class to an object allows me to call the method and get the object, but now I'm unable to cast it as the class and use it as intended, getting this exception message when I try: > Unable to cast COM object of type 'System.__ComObject' to class type > 'anaplan.Utility.XYCoordinates'. Instances of types that represent COM > components cannot be cast to types that do not represent COM > components; however they can be cast to interfaces as long as the > underlying COM component supports QueryInterface calls for the IID of > the interface. I've retrieved the Type name using VisualBasic.Information.TypeName and it's showing it as the class I expect. Is there any way to get the comobject cast back to the class? Or another way to access the properties it has? Or am I just being a bit stupid here?

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• Creating simple calculator with bison & flex in C++ (not C)

  - by ak91

  Hey, I would like to create simple C++ calculator using bison and flex. Please note I'm new to the creating parsers. I already found few examples in bison/flex but they were all written in C. My goal is to create C++ code, where classes would contain nodes of values, operations, funcs - to create AST (evaluation would be done just after creating whole AST - starting from the root and going forward). For example: my_var = sqrt(9 ** 2 - 32) + 4 - 20 / 5 my_var * 3 Would be parsed as: = / \ my_var + / \ sqrt - | / \ - 4 / / \ / \ ** 32 20 5 / \ 9 2 and the second AST would look like: * / \ my_var 3 Then following pseudocode reflects AST: ast_root = create_node('=', new_variable("my_var"), exp) where exp is: exp = create_node(OPERATOR, val1, val2) but NOT like this: $$ = $1 OPERATOR $3 because this way I directly get value of operation instead of creation the Node. I believe the Node should contain type (of operation), val1 (Node), val2 (Node). In some cases val2 would be NULL, like above mentioned sqrt which takes in the end one argument. Right? It will be nice if you can propose me C++ skeleton (without evaluation) for above described problem (including *.y file creating AST) to help me understand the way of creating/holding Nodes in AST. Code can be snipped, just to let me get the idea. I'll also be grateful if you point me to an existing (possibly simple) example if you know any. Thank you all for your time and assistance!

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• zend-framework doctrine, and mvc pattern: what should connect data between models and forms?

  - by Skirmantas

  I am learning Zend Framework and Doctrine. I am wondering what is the best practice to connect forms to models and vice versa. I don't know where I should put my code. I have seen in Zendcast video tutorials where author creates methods like mapFormToRecord and mapRecordToForm in form class. Well I guess it is very handy when form is sophisticated and uses many records. Is it a good practice? I somehow believe that form-class should not need to know about data-records. And sometimes we might have model which is used in many forms. So It would be handy to have few functions in that model which would help to prepare data for forms. For example to give an array of id=name pairs so that it might be used in Zend_Form_Element_Select. However I would like to have a consistency. So I don't want to put this code nor in model nor in form because on different situations I act different. So only controller is what is left to deal it. However this will result in code duplication if one form will be used more than in one controller. Moreover controller gets bloated if form is not from the simple ones. Or maybe there is a consistent pattern in those data conversions between forms and models? I think that there is. At least in my simple cases. So maybe a separate class could be a solution? Where should I put such class and how should I name it? Another question: Zend_Form has validators and filter. Doctrine has validators and filters too. Which do we use and when? What is your way of dealing the connections between forms and models? (Sorry if it was hard for you to read my text. I don't have enough knowledge of English language to express myself freely)

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• Algorithm to determine if array contains n...n+m?

  - by Kyle Cronin

  I saw this question on Reddit, and there were no positive solutions presented, and I thought it would be a perfect question to ask here. This was in a thread about interview questions: Write a method that takes an int array of size m, and returns (True/False) if the array consists of the numbers n...n+m-1, all numbers in that range and only numbers in that range. The array is not guaranteed to be sorted. (For instance, {2,3,4} would return true. {1,3,1} would return false, {1,2,4} would return false. The problem I had with this one is that my interviewer kept asking me to optimize (faster O(n), less memory, etc), to the point where he claimed you could do it in one pass of the array using a constant amount of memory. Never figured that one out. Along with your solutions please indicate if they assume that the array contains unique items. Also indicate if your solution assumes the sequence starts at 1. (I've modified the question slightly to allow cases where it goes 2, 3, 4...) edit: I am now of the opinion that there does not exist a linear in time and constant in space algorithm that handles duplicates. Can anyone verify this? The duplicate problem boils down to testing to see if the array contains duplicates in O(n) time, O(1) space. If this can be done you can simply test first and if there are no duplicates run the algorithms posted. So can you test for dupes in O(n) time O(1) space?

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• PHP: Extract direct sub directory from path string

  - by Nebs

  I need to extract the name of the direct sub directory from a full path string. For example, say we have: $str = "dir1/dir2/dir3/dir4/filename.ext"; $dir = "dir1/dir2"; Then the name of the sub-directory in the $str path relative to $dir would be "dir3". Note that $dir never has '/' at the ends. So the function should be: $subdir = getsubdir($str,$dir); echo $subdir; // Outputs "dir3" If $dir="dir1" then the output would be "dir2". If $dir="dir1/dir2/dir3/dir4" then the output would be "" (empty). If $dir="" then the output would be "dir1". Etc.. Currently this is what I have, and it works (as far as I've tested it). I'm just wondering if there's a simpler way since I find I'm using a lot of string functions. Maybe there's some magic regexp to do this in one line? (I'm not too good with regexp unfortunately). function getsubdir($str,$dir) { // Remove the filename $str = dirname($str); // Remove the $dir if(!empty($dir)){ $str = str_replace($dir,"",$str); } // Remove the leading '/' if there is one $si = stripos($str,"/"); if($si == 0){ $str = substr($str,1); } // Remove everything after the subdir (if there is anything) $lastpart = strchr($str,"/"); $str = str_replace($lastpart,"",$str); return $str; } As you can see, it's a little hacky in order to handle some odd cases (no '/' in input, empty input, etc). I hope all that made sense. Any help/suggestions are welcome.

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• Web services or shared database for (game) server communication?

  - by jaaronfarr

  We have 2 server clusters: the first is made up of typical web applications backed by SQL databases. The second are highly optimized multiplayer game servers which keep all data in memory. Both clusters communicate with clients via HTTP (Ajax with JSON). There are a few cases in which we need to share data between the two server types, for example, reporting back and storing the results of a game (should ultimately end up in the database). We're considering several approaches for inter-server communication: Just share the MySQL databases between clusters (introduce SQL to the game servers) Sharing data in a distributed key-value store like Memcache, Redis, etc. Use an RPC technology like Google ProtoBufs or Apache Thrift Using RESTful web services (the game server would POST back to the web servers, for example) At the moment, we're leaning towards web services or just sharing the database. Sharing the database seems easy, but we're concerned this adds extra memory and a new dependency into the game servers. Web services provide good separation of concerns and fit with the existing Ajax we use, but add complexity, overhead and many more ways for communication to fail. Are there any other good reasons not to use one or the other approach? Which would be easier to scale?

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• Populate JOIN into a list in one database query

  - by axio

  I am trying to get the records from the 'many' table of a one-to-many relationship and add them as a list to the relevant record from the 'one' table. I am also trying to do this in a single database request. Code derived from http://stackoverflow.com/questions/1580199/linq-to-sql-populate-join-result-into-a-list almost achieves the intended result, but makes one database request per entry in the 'one' table which is unacceptable. That failing code is here: var res = from variable in _dc.GetTable<VARIABLE>() select new { x = variable, y = variable.VARIABLE_VALUEs }; However if I do a similar query but loop through all the results, then only a single database request is made. This code achieves all goals: var res = from variable in _dc.GetTable<VARIABLE>() select variable; List<GDO.Variable> output = new List<GDO.Variable>(); foreach (var v2 in res) { List<GDO.VariableValue> values = new List<GDO.VariableValue>(); foreach (var vv in v2.VARIABLE_VALUEs) { values.Add(VariableValue.EntityToGDO(vv)); } output.Add(EntityToGDO(v2)); output[output.Count - 1].VariableValues = values; } However the latter code is ugly as hell, and it really feels like something that should be do-able in a single linq query. So, how can this be done in a single linq query that makes only a single database query? In both cases the table is set to preload using the following code: _dc = _db.CreateLinqDataContext(); var loadOptions = new DataLoadOptions(); loadOptions.LoadWith<VARIABLE>(v => v.VARIABLE_VALUEs); _dc.LoadOptions = loadOptions; I am using .NET 3.5, and the database back-end was generated using SqlMetal.

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• When to define SDD(System Sequence Diagram) operations System->Actor?

  - by devoured elysium

  I am having some trouble understanding how to make System Sequence Diagrams, as I don't fully grasp why in some cases one should define operations for System - Actor and in others don't. Here is an example: Let's assume the System is a Cinema Ticket Store and the Actor is a client that wants to buy a ticket. 1) The User tells the System that wants to buy some tickets, stating his client number. 2) The System confirms that the given client number is valid. 3) The User tells the System the movie that wants to see. 4) The System shows the set of available sessions and seats for that movie. 5) The System asks the user which session/seat he wants. 6) The User tells the System the chosen session/seat. This would be converted to: a) -----> tellClientNumber(clientNumber) b) <----- validClientNumber c) -----> tellMovieToSee(movie) d) <----- showsAvailableSeatsHours e) -----> tellSystemChosenSessionSeat(session, seat) I know that when we are dealing with SDD's we are still far away from coding. But I can't help trying to imagine how it how it would have been had I to convert it right away to code: I can understand 1) and 2). It's like if it was a C#/Java method with the following signature: boolean tellClientNumber(clientNumber) so I put both on the SDD. Then, we have the pair 3) 4). I can imagine that as something as: SomeDataStructureThatHoldsAvailableSessionsSeats tellSystemMovieToSee(movie) Now, the problem: From what I've come to understand, my lecturer says that we shouldn't make an operation on the SDD for 5) as we should only show operations from the Actor to the System and when the System is either presenting us data (as in c)) or validating sent data (such as in b)). I find this odd, as if I try to imagine this like a DOS app where you have to put your input sequencially, it makes sense to make an arrow even for 5). Why is this wrong? How should I try to visualize this? Thanks

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• Javascript Graph Layout Engine

  - by GJK

  I'm looking for a Javascript library/engine that can do graph layouts. (And when I say layouts, I mean logically position vertices nicely.) The graphs I'm working with are all m-ary trees. M is usually no more than 5 or 6, but it can be greater in some cases. I do have something that I use now, Graphviz's node program, and it works perfectly. The problem is, when running a web app, I have to send a request to the server every time I want a layout. Preferably, I would like something written in Javascript that can be quickly run on the client side. All it needs to do is provide layout information (relative positioning and whatnot). I don't need it to draw to a canvas or use SVG or anything, all I'm interested in is the layout. Library use like jQuery or RaphaelJS is fine by me. I'll work with it. I'm just looking for something to speed things along a little. Also, I'd consider writing my own if I could find a nice description of an algorithm to do the layouts. But I really don't want to spend too much time. I have something that works now, so getting it on the client side is just a bonus, not a necessity.

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• Typical Search, Result and Detail Workflow Staying Within an Android Tab

  - by Justin

  So, I've been banging my head looking for a good solution for a few days and am stuck. I have a search screen (Activity) in a tab, and after the user enters a value and clicks "search" I would like the results to come back in that same tab, and then if an item from the results is selected, to show more detailed results, in that same tab. I have it all working now in separate activities, and even the first step working in a tab, but as soon as I call the activity to process he search results... i.e. startActivity(i); for the results Activity, the results displayed are not in the tab! I am having a very difficult time getting this flow to work all under a tab. Any thoughts on how to make this happen? I keep hearing that Android views should be used instead of activities, but am I then to assume that all the logic I have right now for 3 activity needs to go inside 1 activity and then I need to handle setting the content and state for each of these cases? Plus, won't the history stack not work as pressing the back button will take the user out of the application, instead of taking them from say the search result to the search screen, or the details to the search results, etc. This seems like a mess. Can anyone show a more complex example of tabs or how one might have a simple search, result and detail workflow staying in a tab? I have seen a few questions on this concept of keeping activities "within a tab", but no good resolution. Please help.

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• Defining and using controller methods in ember.js

  - by OriginalEXE

  first of all, I am total noob when it comes to OOP in JS, this is new to me so treat me like a noob. I am building my first ember.js application and I am stuck (not the first time but I would get unstuck by myself, this is a tough one though). I have two models: forms entries Entries is of course in (one to many) relationship to forms, so each form can have as many properties. Form properties: id : DS.attr( 'number' ), title : DS.attr( 'string' ), views : DS.attr( 'number' ), conversion : DS.attr( 'number' ), entries : DS.hasMany( 'entry' ) Entry properties: id : DS.attr( 'number' ), parent_id: DS.belongsTo( 'form' ) Now, I have forms route that displays all forms in tabled view, and each table row has some info like form id, name etc. and that works great. What I wanted to do is display the number of entries each form has. I figured I should do that via controller, so here is my controller now: // Form controller App.FormController = Ember.ObjectController.extend({ entriescount: function() { var entries = this.get( 'store').find( 'entry' ); return entries.filterBy( 'parent_id', this.get( 'id' ) ).get( 'length' ); }.property( '[email protected]_id') }); Now for some reason, when I use {{entriescount}} in {{#each}} loop, this returns nothing. It also returns nothing in single form route. Note that in both cases, {{title}} for example works. I am wondering, am I going the right way by using controller for this, and how do I get controller to output the data. Thanks

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