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  • avoiding code duplication in Rails 3 models

    - by Dustin Frazier
    I'm working on a Rails 3.1 application where there are a number of different enum-like models that are stored in the database. There is a lot of identical code in these models, as well as in the associated controllers and views. I've solved the code duplication for the controllers and views via a shared parent controller class and the new view/layout inheritance that's part of Rails 3. Now I'm trying to solve the code duplication in the models, and I'm stuck. An example of one of my enum models is as follows: class Format < ActiveRecord::Base has_and_belongs_to_many :videos attr_accessible :name validates :name, presence: true, length: { maximum: 20 } before_destroy :verify_no_linked_videos def verify_no_linked_videos unless self.videos.empty? self.errors[:base] << "Couldn't delete format with associated videos." raise ActiveRecord::RecordInvalid.new self end end end I have four or five other classes with nearly identical code (the association declaration being the only difference). I've tried creating a module with the shared code that they all include (which seems like the Ruby Way), but much of the duplicate code relies on ActiveRecord, so the methods I'm trying to use in the module (validate, attr_accessible, etc.) aren't available. I know about ActiveModel, but that doesn't get me all the way there. I've also tried creating a common, non-persistent parent class that subclasses ActiveRecord::Base, but all of the code I've seen to accomplish this assumes that you won't have subclasses of your non-persistent class that do persist. Any suggestions for how best to avoid duplicating these identical lines of code across many different enum models?

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  • Matching on search attributes selected by customer on front end

    - by CodeNinja1974
    I have a method in a class that allows me to return results based on a certain set of Customer specified criteria. The method matches what the Customer specifies on the front end with each item in a collection that comes from the database. In cases where the customer does not specify any of the attributes, the ID of the attibute is passed into the method being equal to 0 (The database has an identity on all tables that is seeded at 1 and is incremental). In this case that attribute should be ignored, for example if the Customer does not specify the Location then customerSearchCriteria.LocationID = 0 coming into the method. The matching would then match on the other attributes and return all Locations matching the other attibutes, example below: public IEnumerable<Pet> FindPetsMatchingCustomerCriteria(CustomerPetSearchCriteria customerSearchCriteria) { if(customerSearchCriteria.LocationID == 0) { return repository.GetAllPetsLinkedCriteria() .Where(x => x.TypeID == customerSearchCriteria.TypeID && x.FeedingMethodID == customerSearchCriteria.FeedingMethodID && x.FlyAblityID == customerSearchCriteria.FlyAblityID ) .Select(y => y.Pet); } } The code for when all criteria is specified is shown below: private PetsRepository repository = new PetsRepository(); public IEnumerable<Pet> FindPetsMatchingCustomerCriteria(CustomerPetSearchCriteria customerSearchCriteria) { return repository.GetAllPetsLinkedCriteria() .Where(x => x.TypeID == customerSearchCriteria.TypeID && x.FeedingMethodID == customerSearchCriteria.FeedingMethodID && x.FlyAblityID == customerSearchCriteria.FlyAblityID && x.LocationID == customerSearchCriteria.LocationID ) .Select(y => y.Pet); } I want to avoid having a whole set of if and else statements to cater for each time the Customer does not explicitly select an attribute of the results they are looking for. What is the most succint and efficient way in which I could achieve this?

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  • Split UInt32 (audio frame) into two SInt16s (left and right)?

    - by morgancodes
    Total noob to anything lower-level than Java, diving into iPhone audio, and realing from all of the casting/pointers/raw memory access. I'm working with some example code wich reads a WAV file from disc and returns stereo samples as single UInt32 values. If I understand correctly, this is just a convenient way to return the 32 bits of memory required to create two 16 bit samples. Eventually this data gets written to a buffer, and an audio unit picks it up down the road. Even though the data is written in UInt32-sized chunks, it eventually is interpreted as pairs of 16-bit samples. What I need help with is splitting these UInt32 frames into left and right samples. I'm assuming I'll want to convert each UInt32 into an SInt16, since an audio sample is a signed value. It seems to me that for efficiency's sake, I ought to be able to simply point to the same blocks in memory, and avoid any copying. So, in pseudo-code, it would be something like this: UInt32 myStereoFrame = getFramefromFilePlayer; SInt16* leftChannel = getFirst16Bits(myStereoFrame); SInt16* rightChannel = getSecond16Bits(myStereoFrame); Can anyone help me turn my pseudo into real code?

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  • Immutability and shared references - how to reconcile?

    - by davetron5000
    Consider this simplified application domain: Criminal Investigative database Person is anyone involved in an investigation Report is a bit of info that is part of an investigation A Report references a primary Person (the subject of an investigation) A Report has accomplices who are secondarily related (and could certainly be primary in other investigations or reports These classes have ids that are used to store them in a database, since their info can change over time (e.g. we might find new aliases for a person, or add persons of interest to a report) If these are stored in some sort of database and I wish to use immutable objects, there seems to be an issue regarding state and referencing. Supposing that I change some meta-data about a Person. Since my Person objects immutable, I might have some code like: class Person( val id:UUID, val aliases:List[String], val reports:List[Report]) { def addAlias(name:String) = new Person(id,name :: aliases,reports) } So that my Person with a new alias becomes a new object, also immutable. If a Report refers to that person, but the alias was changed elsewhere in the system, my Report now refers to the "old" person, i.e. the person without the new alias. Similarly, I might have: class Report(val id:UUID, val content:String) { /** Adding more info to our report */ def updateContent(newContent:String) = new Report(id,newContent) } Since these objects don't know who refers to them, it's not clear to me how to let all the "referrers" know that there is a new object available representing the most recent state. This could be done by having all objects "refresh" from a central data store and all operations that create new, updated, objects store to the central data store, but this feels like a cheesy reimplementation of the underlying language's referencing. i.e. it would be more clear to just make these "secondary storable objects" mutable. So, if I add an alias to a Person, all referrers see the new value without doing anything. How is this dealt with when we want to avoid mutability, or is this a case where immutability is not helpful?

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  • algorithm to find longest non-overlapping sequences

    - by msalvadores
    I am trying to find the best way to solve the following problem. By best way I mean less complex. As an input a list of tuples (start,length) such: [(0,5),(0,1),(1,9),(5,5),(5,7),(10,1)] Each element represets a sequence by its start and length, for example (5,7) is equivalent to the sequence (5,6,7,8,9,10,11) - a list of 7 elements starting with 5. One can assume that the tuples are sorted by the start element. The output should return a non-overlapping combination of tuples that represent the longest continuos sequences(s). This means that, a solution is a subset of ranges with no overlaps and no gaps and is the longest possible - there could be more than one though. For example for the given input the solution is: [(0,5),(5,7)] equivalent to (0,1,2,3,4,5,6,7,8,9,10,11) is it backtracking the best approach to solve this problem ? I'm interested in any different approaches that people could suggest. Also if anyone knows a formal reference of this problem or another one that is similar I'd like to get references. BTW - this is not homework. Edit Just to avoid some mistakes this is another example of expected behaviour for an input like [(0,1),(1,7),(3,20),(8,5)] the right answer is [(3,20)] equivalent to (3,4,5,..,22) with length 20. Some of the answers received would give [(0,1),(1,7),(8,5)] equivalent to (0,1,2,...,11,12) as right answer. But this last answer is not correct because is shorter than [(3,20)].

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  • Business Tier | client state in desktop application- way around Stateful Session Beans?

    - by arthur
    I read positive inputs on the following posts concerning client state management: Stateful EJBs in web application?, here, and here. I want to know how implement such client state management for desktop applications (Swing, AWT, SWT, and other). let's assume there are n desktop clients supposed to use some (remote) services provided on an Application Server. How to maintain a separate and permanent data state for each client , distinct from the other without have to use using stateful session Beans (SFSB) ? is that even possible on this application type ? With Webapp(Servlets / JsSF and JSP) some can avoid using SFSB by HttpSession object and/or coupling it with stateless session beans (SLSB). HttpSession object would keep information for each (Web)client separate and the SLSB would play the business logic music. But HttpSession objects aren't present on desktop application and I go stuck with only SFSB and SLSB. Knowing the problems(Concurrency, Error Handling, usw ) of SFSB, I would have not wanted to use it. What would be the other options? is there only SFSB available? Thanks in advances

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  • Counting XML elements in file on Android

    - by CSharperWithJava
    Take a simple XML file formatted like this: <Lists> <List> <Note/> ... <Note/> </List> <List> <Note/> ... <Note/> </List> </Lists> Each node has some attributes that actually hold the data of the file. I need a very quick way to count the number of each type of element, (List and Note). Lists is simply the root and doesn't matter. I can do this with a simple string search or something similar, but I need to make this as fast as possible. Design Parameters: Must be in java (Android application). Must AVOID allocating memory as much as possible. Must return the total number of Note elements and the number of List elements in the file, regardless of location in file. Number of Lists will typically be small (1-4), and number of notes can potentially be very large (upwards of 1000, typically 100) per file. I look forward to your suggestions.

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  • Efficient (basic) regular expression implementation for streaming data

    - by Brendan Dolan-Gavitt
    I'm looking for an implementation of regular expression matching that operates on a stream of data -- i.e., it has an API that allows a user to pass in one character at a time and report when a match is found on the stream of characters seen so far. Only very basic (classic) regular expressions are needed, so a DFA/NFA based implementation seems like it would be well-suited to the problem. Based on the fact that it's possible to do regular expression matching using a DFA/NFA in a single linear sweep, it seems like a streaming implementation should be possible. Requirements: The library should try to wait until the full string has been read before performing the match. The data I have really is streaming; there is no way to know how much data will arrive, it's not possible to seek forward or backward. Implementing specific stream matching for a couple special cases is not an option, as I don't know in advance what patterns a user might want to look for. For the curious, my use case is the following: I have a system which intercepts memory writes inside a full system emulator, and I would like to have a way to identify memory writes that match a regular expression (e.g., one could use this to find the point in the system where a URL is written to memory). I have found (links de-linkified because I don't have enough reputation): stackoverflow.com/questions/1962220/apply-a-regex-on-stream stackoverflow.com/questions/716927/applying-a-regular-expression-to-a-java-i-o-stream www.codeguru.com/csharp/csharp/cs_data/searching/article.php/c14689/Building-a-Regular-Expression-Stream-Search-with-the-NET-Framework.htm But all of these attempt to convert the stream to a string first and then use a stock regular expression library. Another thought I had was to modify the RE2 library, but according to the author it is architected around the assumption that the entire string is in memory at the same time. If nothing's available, then I can start down the unhappy path of reinventing this wheel to fit my own needs, but I'd really rather not if I can avoid it. Any help would be greatly appreciated!

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  • trouble calculating offset index into 3D array

    - by Derek
    Hello, I am writing a CUDA kernel to create a 3x3 covariance matrix for each location in the rows*cols main matrix. So that 3D matrix is rows*cols*9 in size, which i allocated in a single malloc accordingly. I need to access this in a single index value the 9 values of the 3x3 covariance matrix get their values set according to the appropriate row r and column c from some other 2D arrays. In other words - I need to calculate the appropriate index to access the 9 elements of the 3x3 covariance matrix, as well as the row and column offset of the 2D matrices that are inputs to the value, as well as the appropriate index for the storage array. i have tried to simplify it down to the following: //I am calling this kernel with 1D blocks who are 512 cols x 1row. TILE_WIDTH=512 int bx = blockIdx.x; int by = blockIdx.y; int tx = threadIdx.x; int ty = threadIdx.y; int r = by + ty; int c = bx*TILE_WIDTH + tx; int offset = r*cols+c; int ndx = r*cols*rows + c*cols; if((r < rows) && (c < cols)){ //this IF statement is trying to avoid the case where a threadblock went bigger than my original array..not sure if correct d_cov[ndx + 0] = otherArray[offset]; d_cov[ndx + 1] = otherArray[offset] d_cov[ndx + 2] = otherArray[offset] d_cov[ndx + 3] = otherArray[offset] d_cov[ndx + 4] = otherArray[offset] d_cov[ndx + 5] = otherArray[offset] d_cov[ndx + 6] = otherArray[offset] d_cov[ndx + 7] = otherArray[offset] d_cov[ndx + 8] = otherArray[offset] } When I check this array with the values calculated on the CPU, which loops over i=rows, j=cols, k = 1..9 The results do not match up. in other words d_cov[i*rows*cols + j*cols + k] != correctAnswer[i][j][k] Can anyone give me any tips on how to sovle this problem? Is it an indexing problem, or some other logic error?

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  • error catching exception while System.out.print

    - by user1702633
    I have 2 classes, one that implements a double lookup( int i); and one where I use that lookup(int i) in solving a question, or in this case printing the lookup values. This case is for an array. So I read the exception documentation or google/textbook and come with the following code: public double lookup(int i) throws Exception { if( i > numItems) throw new Exception("out of bounds"); return items[i]; } and take it over to my class and try to print my set, where set is a name of the object type I define in the class above. public void print() { for (int i = 0; i < set.size() - 1; i++) { System.out.print(set.lookup(i) + ","); } System.out.print(set.lookup(set.size())); } I'm using two print()'s to avoid the last "," in the print, but am getting an unhandled exception Exception (my exception's name was Exception) I think I have to catch my exception in my print() but cannot find the correct formatting online. Do I have to write catch exception Exception? because that gives me a syntax error saying invalid type on catch. Sources like http://docs.oracle.com/javase/tutorial/essential/exceptions/ are of little help to me, I'm can't seem to grasp what the text is telling me. I'm also having trouble finding sources with multiple examples where I can actually understand the coding in the examples. so could anybody give me a source/example for the above catch phrase and perhaps a decent source of examples for new Java programmers? my book is horrendous and I cannot seem to find an understandable example for the above catch phrase online.

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  • Updating a Database from DataBound Controls

    - by Avatar_Squadron
    Hi. I'm currently creating a WinForm in VB.NET bound to an access database. Basically what i have are two forms: one is a search form used to search the database, and the other is a details form. You run a search on the searchForm and it returns a list of Primary Keys and a few other identifying values. You then double click on the entry you want to view, and it loads the details form. The Details form has a collection of databound controls to display the data: mostly text boxes and checkboxs. The way i've set it up is i used the UI to build the form and then set the DataBindings Property of each control to "TblPropertiesBindingSource - " where value name is one of the values in the table (such as PropertyID or HasWoodFloor). Then, when you double click an entry in the searchform, I handle the event by parsing the Primary Key (PropertyID) out of the selected row and then storing this to the details form: Note: Detail is the details form that is opened to display the info Private Sub propView_CellDoubleClick(ByVal sender As Object, ByVal e As System.Windows.Forms.DataGridViewCellEventArgs) Handles propView.CellDoubleClick Dim detail As frmPropertiesDetail = New frmPropertiesDetail detail.id = propView.Rows(e.RowIndex).Cells(0).Value detail.Show() End Sub Then, upon loading the details form, it set's the filter on the BindSource as such: TblPropertiesBindingSource.Filter() = "PropertyID=" & id This works great so far. All the controls on the details form will display the correct info. The problem is updating changes. Scenario: If i have the user load the details for say, property 10001, it will show a description in a textBox named descriptionBox which is identical to the value of the description value of for that entry in the database. I want the user to then be able to change the text of the text box (which they can currently do) and click the save button (saveBut) and have the form update all the values in the controls to the database. Theorectically, it should do this as the controls are DataBound, thus i can avoid writing code that tells each entry in the database row to take the value of the aligned control. I've tried calleding PropertiesTableAdapter.Update(PropertiesBindingSource.DataSource), but that doesnt seem to do it.

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  • are there requirements for Struts setters beyond variable name matching?

    - by slk
    I have a model-driven Struts Web action: public class ModelDrivenAction<T extends Object> implements ModelDriven<T>, Preparable { protected Long id; protected T model; @Override public void prepare() {} public void setId(Long id) { this.id = id; } @Override public T getModel() { return model; } public void setModel(T model) { this.model = model; } } I have another action which is not currently model-driven: public class OtherAction implements Preparable { private ModelObj modelObj; private Long modelId; @Override public void prepare() { modelObj = repoService.retrieveModelById(modelId); } public void setModelId(Long modelId) { this.modelId = modelId; } } I wish to make it so, and would like to avoid having to track down all the instances in JavaScript where the action is passed a "modelId" parameter instead of "id" if at all possible. I thought this might work, so either modelId or id could be passed in: public class OtherAction extends ModelDrivenAction<ModelObj> { @Override public void prepare() { model = repoService.retrieveModelById(id); } public void setModelId(Long modelId) { this.id = modelId; } } However, server/path/to/other!method?modelId=123 is failing to set id. I thought so long as a setter matched a parameter name the Struts interceptor would call it on action invocation. Am I missing something here?

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  • Handling Denormalized Schema with Eclipselink

    - by iamrohitbanga
    Hello All I have a denormalized table containing employee information. The fields are employee id, name and department name. The primary key is a composite one consisting of all three fields. An employee can belong to multiple departments. I want to read/write the objects in the table using the Eclipselink Dynamic Persistence API (which is infact a wrapper on top of JPA descriptors etc.). Example Data: 1 e1 dep1 2 e1 dep2 3 e2 dep1 4 e2 dep3 5 e3 dep1 5 e3 dep2 5 e3 dep3 A normal ReadAllQuery (select query) on the table returns a DynamicEntity corresponding to each row in the table. However I want to club all entities based on the emp id and return all the departments he belongs to as a list. I can merge the entities after retrieving them but if I can use some Eclipselink feature out of the box then it would be better. One way to do the read is the following: I create two dynamic types corresponding to employee: Having id,name as the primary key Having id, department as the primary key, I create a OneToManyMapping from the first type to the second one. Then when I query the first type it does return the departments to which employee belongs as a list of DynamicEntity of the second type. This satisfies the read scenario. Is there a better way of doing this? Is this inherently supported by Eclipselink or JPA? I cannot get the same dynamic type configuration working for the write scenario. This is because when I write the changes using the writeObject method of UnitOfWork, it generates insert queries which enter the following entries in the table id name department 102 emp_102 102 st 102 dep_102 102 dep_102 102 dep_102 instead of: id name department 102 emp_102 st 102 emp_102 dep_102 102 emp_102 dep_102 102 emp_102 dep_102 Is there any way I can get write to work with this schema using eclipselink? I want to avoid doing the heavy lifting of merging the rows for such a denormalized schema or generating each row before doing a write. Is there no clean way of doing this using Eclipselink or JPA? Thanks in Advance.

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  • Unable to delete inherited entity class in EF4

    - by Coding Gorilla
    I have two entities in an EF4 model (using Model First), let's call them EntityA and EntityB. EntityA is marked as abstract, and EntityB inherits from EntityA. They are similar to the following: public class EntityA { public Guid Id; public string Name; public string Uri; } public class EntityB : EntityA { public string AnotherProperty; } The generated database tables look as I would expect them, with EntityA as on table, and then another table like: EntityA_EntityB Id (PK, FK, uniqueidentifier) AnotherProperty (varchar) There is a foreign key constraint on EntityA_EntityB that references EntityA's Id property, no cascades are configured (although I did try changing these myself). The problem is that when I attempt to do something like: Context.DeleteObject(EntityA_EntityB); EF attempts to delete the EntityA_EntityB table record before deleting the EntityA table record, which of course violates the foreign key constraint on EntityA_EntityB table. Using EFProfiler I see the following commands being sent to the database: delete [dbo].[EntityA_EntityB] where (([Id] = '5c02899f-09ea-2ed9-d44b-01aef80f6b64' /* @0 */) followed by delete [dbo].[EntityA] where ([Id] = '5c02899f-09ea-2ed9-d44b-01aef80f6b64' /* @0 */) I'm completely stumped as to how to get around this problem. I would think the EF should know that it needs to delete the base class first, before deleting the inherited class. I know I could do some triggers or other database type solutions, but I'd rather avoid doing that if I can. All my classes are POCO built using some customized T4 templates. I don't want to paste in a lot of extraneous code, but if you need more information I'll provide what I can.

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  • Suggestions for opening the Rails toolbox to design a challenge game?

    - by keruilin
    How would you suggest designing a challenge system as part of a food-eating game so that it's automated as possible? All RoR tools, design patterns and logic are at your disposal (e.g., admin consoles, crontab, arch, etc.). Prize goes to whoever can suggest the simplest and most-automated design! Here are the requirements: User has many challenges. Badge has many challenges. (A unique badge is awarded for each challenge won.) Only one challenge can run at a time. Each challenge has a limited number of days that it runs. For example, one challenge can run 3 days, while another runs 7 days. Challenges can be seasonal. For example, "Eat 13 Pumpkins" only runs during the Fall. New challenges are added to the game on an ongoing basis. For example, a new challenge every week. Each challenge has a certain probability of being selected to run. For example, "Eat 10 Pies" challenge has 10% chance of being selected to run. As each new challenge is added to the database, I want the probabilities of running to change dynamically. I want to avoid the scenario where I'm manually updating a database field just to change the probability from 10% to 5%, for example. Challenges act like Easter eggs. Challenge icons pop-up at different places on the webpage. User is awarded a badge for successfully completing a challenge, but only when it's active. There is some wait time between each challenge. Between 1 and 7 days. Which wait time is random, but the probability of the wait time being short is high and the probability of it being a long wait time is low.

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  • Migrating MachineKey from iis6 on old server to iis7 on new server

    - by MaseBase
    I am migrating our hosting environment to a totally new data center with new boxes and hardware and software... the whole deal. Our website cookies are encrypted using the machineKey, so when I make a request to my domain and point it to the new web server (by overriding the local hosts file), I get an error because the cookie cannot be decrypted, since the Machine Key is different. I'd like to avoid any problems a frequent user might have when they arrive at the new server for the first time. To the best of my knowledge, at this point I think I need to set the same MachineKey from our current servers on our new servers. This way when past visitors with a cookie arrive at our website served by the new server, the cookie will be decrypted properly with the MachineKey it was encrypted with and then log them in properly. My question is where do I find my MachineKey value (in IIS 6 win2k3 server) so I can use that value to set it statically on my new servers? I've pulled up my machine.config file, but it doesn't specify the key, it only specifies a configSection where the key can be defined. It's not in my web.config for the app or elsewhere. I did find this great article on some MachineKey and Web Garden woes (which could explain some other bugs I've been experiencing with regard to the machineKey). Update I am back to this issue and am still faced with a similar problem. I have the MachineKey auto-generated on the IIS6 server but I need to get that exact key so I can set it explicitly and not have it auto-generated anymore. Any help is appreciated...

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  • C++, array declaration, templates, linker error

    - by justik
    There is a linker error in my SW. I am using the following structure based on h, hpp, cpp files. Some classes are templatized, some not, some have function templates. Declaration: test.h #ifndef TEST_H #define TEST_H class Test { public: template <typename T> void foo1(); void foo2 () }; #include "test.hpp" #endif Definition: test.hpp #ifndef TEST_HPP #define TEST_HPP template <typename T> void Test::foo1() {} inline void Test::foo2() {} //or in cpp file #endif CPP file: test.cpp #include "test.h" void Test::foo2() {} //or in hpp file as inline I have the following problem. The variable vars[] is declared in my h file test.h #ifndef TEST_H #define TEST_H char *vars[] = { "first", "second"...}; class Test { public: void foo(); }; #include "test.hpp" #endif and used as a local variable inside foo() method defined in hpp file as inline. test.hpp #ifndef TEST_HPP #define TEST_HPP inline void Test::foo() { char *var = vars[0]; //A Linker Error } #endif However, the following linker error occurs: Error 745 error LNK2005: "char * * vars" (?vars@@3PAPADA) already defined in test2.obj How and where to declare vars[] to avoid linker errors? After including #include "test.hpp" it is late to declare it...

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  • boost thread pool

    - by Dtag
    I need a threadpool for my application, and I'd like to rely on standard (C++11 or boost) stuff as much as possible. I realize there is an unofficial(!) boost thread pool class, which basically solves what I need, however I'd rather avoid it because it is not in the boost library itself -- why is it still not in the core library after so many years? In some posts on this page and elsewhere, people suggested using boost::asio to achieve a threadpool like behavior. At first sight, that looked like what I wanted to do, however I found out that all implementations I have seen have no means to join on the currently active tasks, which makes it useless for my application. To perform a join, they send stop signal to all the threads and subsequently join them. However, that completely nullifies the advantage of threadpools in my use case, because that makes new tasks require the creation of a new thread. What I want to do is: ThreadPool pool(4); for (...) { for (int i=0;i<something;i++) pool.pushTask(...); pool.join(); // do something with the results } Can anyone suggest a solution (except for using the existing unofficial thread pool on sourceforge)? Is there anything in C++11 or core boost that can help me here? Thanks a lot

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  • Where to place interactive objects in JavaScript?

    - by Chris
    I'm creating a web based application (i.e. JavaScript with jQuery and lots of SVG) where the user interacts with "objects" on the screen (think of DIVs that can be draged around, resized and connected by arraows - like a vector drawing programm or a graphical programming language). As each "object" contains individual information but is allways belonging to a "class" of elements it's obvious that this application should be programmed by using an OOP approach. But where do I store the "objects" best? Should I create a global structure ("registry") with all (JS native) objects and tell them "draw yourself on the DOM"? Or should I avoid such a structure and think of the (relevant) DOM nodes as my objects and attach the relevant data as .data() to them? The first approach is very MVC - but I guess the attachment of all the event handlers will be non trivial. The second approach will handle the events in a trivial way and it doesn't create a duplicate structure, but I guess the usual OO stuff (like methods) will be more complex. What do you recomend? I think the answer will be JavaScript and SVG specific as "usual" programming languages don't have such a highly organized output "canvas".

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  • How to create a desktop shortcut to a website with website logo as icon?

    - by Wbdvlpr
    Hi I need a solution which allows users to create a desktop shortcut to a website, preferably with website logo as shortcut icon. There are ways users can create shortcut such as drag drop favicon or right click create new shortcut etc. This works but also creates the shortcut with default IE icon on windows. I am trying to avoid this method for this icon and some other reasons. I thought of creating a website-title.URL file, and tell users to download and save file to their desktop, again this works but doesn't solve the icon problem as the website logo (.ico) has to be at local disk and at a pre-specified location [IconFile=path]. I was wondering if it is possible to create a some sort of installer or windows application which users can download from the website. Once its executed by user, it creates this .URL file on user desktop which have IconFile path pre-specified, and copy the website-logo.ico at path specified in .URL file etc. So my questions are - Is it possible to create such a solution? What programming languages can be used to achieve this? Can this installer/app be made to work on non-windows machines as well? From developments point of view how big project it is? if I have to hire a programmer to do this. Please let me know if you need more information. Thanks

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  • A better way of getting a data table with various column types into string array

    - by Vlad
    This should be an easy one, looks like I got myself too confused. I get a table from a database, data ranges from varchar to int to Null values. Cheap and dirty way of converting this into a tab-delimited file that I already have is this (shrunken to preserve space, ugliness is kept on par with original): da.Fill(dt) ' da - DataAdapter ' ' dt - DataTable ' Dim lColumns As Long = dt.Columns.Count Dim arrColumns(dt.Columns.Count) As String Dim arrData(dt.Columns.Count) As Object Dim j As Long = 0 Dim arrData(dt.Columns.Count) As Object For i = 0 To dt.Rows.Count - 1 arrData = dt.Rows(i).ItemArray() For j = 0 To arrData.GetUpperBound(0) - 1 arrColumns(j) = arrData(j).ToString Next wrtOutput.WriteLine(String.Join(strFieldDelimiter, arrColumns)) Array.Clear(arrColumns, 0, arrColumns.GetLength(0)) Array.Clear(arrData, 0, arrData.GetLength(0)) Next Not only this is ugly and inefficient, it is also getting on my nerves. Besides, I want, if possible, to avoid the infamous double-loop through the table. I would really appreciate a clean and safe way of rewriting this piece. I like the approach that is used here - especially that is trying to solve the same problem that I have, but it crashes on me when I apply it to my case directly.

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  • ASP ListView - Eval() as formatted number, Bind() as unformatted?

    - by chucknelson
    I have an ASP ListView, and have a very simple requirement to display numbers as formatted w/ a comma (12,123), while they need to bind to the database without formatting (12123). I am using a standard setup - ListView with a datasource attached, using Bind(). I converted from some older code, so I'm not using ASP.NET controls, just form inputs...but I don't think it matters for this: <asp:SqlDataSource ID="MySqlDataSource" runat="server" ConnectionString='<%$ ConnectionStrings:ConnectionString1 %>' SelectCommand="SELECT NUMSTR FROM MY_TABLE WHERE ID = @ID" UpdateCommand= "UPDATE MY_TABLE SET NUMSTR = @NUMSTR WHERE ID = @ID"> </asp:SqlDataSource> <asp:ListView ID="MyListView" runat="server" DataSourceID="MySqlDataSource"> <LayoutTemplate> <div id="itemplaceholder" runat="server"></div> </LayoutTemplate> <ItemTemplate> <input type="text" name="NUMSTR" ID="NUMSTR" runat="server" value='<%#Bind("NUMSTR")%>' /> <asp:Button ID="UpdateButton" runat="server" Text="Update" Commandname="Update" /> </ItemTemplate> </asp:ListView> In the example above, NUMSTR is a number, but stored as a string in a SqlServer 2008 database. I'm also using the ItemTemplate as read and edit templates, to save on duplicate HTML. In the example, I only get the unformatted number. If I convert the field to an integer (via the SELECT) and use a format string like Bind("NUMSTR", "{0:###,###}"), it writes the formatted number to the database, and then fails when it tries to read it again (can't convert with the comma in there). Is there any elegant/simple solution to this? It's so easy to get the two-way binding going, and I would think there has to be a way to easily format things as well... Oh, and I'm trying to avoid the standard ItemTemplate and EditItemTemplate approach, just for sheer amount of markup required for that. Thanks!

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  • C++ variable to const expression

    - by user1344784
    template <typename Real> class A{ }; template <typename Real> class B{ }; //... a few dozen more similar template classes class Computer{ public slots: void setFrom(int from){ from_ = from; } void setTo(int to){ to_ = to; } private: template <int F, int T> void compute(){ using boost::fusion::vector; using boost::fusion::at_c; vector<A<float>, B<float>, ...> v; at_c<from_>(v).operator()(at_c<to_>(v)); //error; needs to be const-expression. }; This question isn't about Qt, but there is a line of Qt code in my example. The setFrom() and setTo() are functions that are called based on user selection via the GUI widget. The root of my problem is that 'from' and 'to' are variables. In my compute member function I need to pick a type (A, B, etc.) based on the values of 'from' and 'to'. The only way I know how to do what I need to do is to use switch statements, but that's extremely tedious in my case and I would like to avoid. Is there anyway to convert the error line to a constant-expression?

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  • Web page for IPhone - Large fonts instead of scrolling?

    - by chris_l
    I'm planning the layout of my web page, which should also be usable on the IPhone. I don't really have much experience with the IPhone yet - I just installed the IPhone Simulator on my Mac. The page's contents are flexible, so I think it would be better to use this flexibility to avoid that the user has to scroll around the entire page. Especially I have A header and a sidebar that will be used all the time to perform several actions. A main content area with a number of elements (e.g. images). The UI would stay usable pretty well, if the number of elements shown at one time is reduced for a small screen (e.g. by JavaScript). It would also be okay to make the main content area scrollable (as opposed to the entire page). The problem: If I simply display the page on the IPhone, it uses an extremely small font size, so that users must zoom in first, and then scroll around - so that they can't see the header and sidebar all the time. What's the best way to deal with this situation? Just leave it this way (very small fonts), because users expect that behaviour on the IPhone? Increase the font size (by specifying it in em or px or with xx-large, or what would be the best way?), if I detect - somehow - that it's being displayed on the IPhone. Or is there some way to restrict the viewport size to the screen size, and make it zoom in automatically? I think that would be the easiest solution in my case. Or ...?

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  • In Silverlight, what structures, aside of the ListBox, can be used for binding?

    - by Aidenn
    I need to simply provide the content of a property to a custom User Control in Silverlight. My control is something like this: <UserControl x:Class="SilverlightApplication.Header" xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation" xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml" xmlns:d="http://schemas.microsoft.com/expression/blend/2008" xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006" mc:Ignorable="d" d:DesignWidth="300" d:DesignHeight="120"> <Grid x:Name="Header_Layout"> <StackPanel x:Name="hiHeaderContent" Width="Auto" Margin="73,8,8,8"> <TextBlock x:Name="User:" Text="{Binding name}" /> </StackPanel> </Grid> I try to use this User Control from another control where I try to pass the parameter "name" to the previous UserControl ("Header"). I don't need to create a "ListBox" as I will only have 1 header, so I try to avoid doing: <ListBox x:Name="HeaderListBox" Grid.Row="0"> <ListBox.ItemTemplate> <DataTemplate> <SilverlightApplication:Header/> </DataTemplate> </ListBox.ItemTemplate> </ListBox> in order to send the "User" account using: HeaderListBox.ItemsSource = name; Is there any other structure I can use instead of the ListBox to pass the parameter just once? It won't be a list, it's just a header... Thank you!

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