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  • Dealing with large number of text strings

    - by Fadrian
    My project when it is running, will collect a large number of string text block (about 20K and largest I have seen is about 200K of them) in short span of time and store them in a relational database. Each of the string text is relatively small and the average would be about 15 short lines (about 300 characters). The current implementation is in C# (VS2008), .NET 3.5 and backend DBMS is Ms. SQL Server 2005 Performance and storage are both important concern of the project, but the priority will be performance first, then storage. I am looking for answers to these: Should I compress the text before storing them in DB? or let SQL Server worry about compacting the storage? Do you know what will be the best compression algorithm/library to use for this context that gives me the best performance? Currently I just use the standard GZip in .NET framework Do you know any best practices to deal with this? I welcome outside the box suggestions as long as it is implementable in .NET framework? (it is a big project and this requirements is only a small part of it) EDITED: I will keep adding to this to clarify points raised I don't need text indexing or searching on these text. I just need to be able to retrieve them in later stage for display as a text block using its primary key. I have a working solution implemented as above and SQL Server has no issue at all handling it. This program will run quite often and need to work with large data context so you can imagine the size will grow very rapidly hence every optimization I can do will help.

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  • Coding the R-ight way - avoiding the for loop

    - by mropa
    I am going through one of my .R files and by cleaning it up a little bit I am trying to get more familiar with writing the code the r-ight way. As a beginner, one of my favorite starting points is to get rid of the for() loops and try to transform the expression into a functional programming form. So here is the scenario: I am assembling a bunch of data.frames into a list for later usage. dataList <- list (dataA, dataB, dataC, dataD, dataE ) Now I like to take a look at each data.frame's column names and substitute certain character strings. Eg I like to substitute each "foo" and "bar" with "baz". At the moment I am getting the job done with a for() loop which looks a bit awkward. colnames(dataList[[1]]) [1] "foo" "code" "lp15" "bar" "lh15" colnames(dataList[[2]]) [1] "a" "code" "lp50" "ls50" "foo" matchVec <- c("foo", "bar") for (i in seq(dataList)) { for (j in seq(matchVec)) { colnames (dataList[[i]])[grep(pattern=matchVec[j], x=colnames (dataList[[i]]))] <- c("baz") } } Since I am working here with a list I thought about the lapply function. My attempts handling the job with the lapply function all seem to look alright but only at first sight. If I write f <- function(i, xList) { gsub(pattern=c("foo"), replacement=c("baz"), x=colnames(xList[[i]])) } lapply(seq(dataList), f, xList=dataList) the last line prints out almost what I am looking for. However, if i take another look at the actual names of the data.frames in dataList: lapply (dataList, colnames) I see that no changes have been made to the initial character strings. So how can I rewrite the for() loop and transform it into a functional programming form? And how do I substitute both strings, "foo" and "bar", in an efficient way? Since the gsub() function takes as its pattern argument only a character vector of length one.

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  • What stackoverflow questions bring out the best in you? [closed]

    - by Mark Robinson
    This question is to help me (us) ask better questions of this community to encourage better working together. What questions here bring out the best in you? I don't mean which are the best / most appropriate questions but which bring the best out of you? That is, it brings out your best thinking and most constructive behaviour. Consider, for example, questions that make you think or that are asked in a certain way. Or consider specific a question should be. Or more abstractly, questions asked on a certain day / time, ... So I'm not necessarily asking about specific subjects but rather how a question is asked. What inspires you to drop everything and start answering? This comes from my observing questions that get highest points - I’m graduating with a Computer Science degree but I don’t feel like I know how to program. is very positive but my first ever question caused a minor storm. Ironically, I'm nervous posting this question so please don't attack if this is inappropriate.

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  • Add to a table with javascript

    - by incrediman
    I have a table which looks like this: <table id='t'> <thead> .... </thead> <tbody id='t_tbody'> </tbody> </table> thead is filled with content tbody is empty I want to use javascript to add this (for example) to t_tbody: <tr> <td>Name</td> <td>Points</td> <td>Information</td> </tr> How can I do this? I need a function which adds the above to t_tbody. Note that simply using document.getElementById('t_tbody').innerHtml+="<tr>...</tr>" works fine in FF, but not in IE. Also note that I need to use raw javascript (ie. no frameworks) for this project, as I am finishing a project which has already been mostly completed using raw javascript.

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  • How do I slow down a flash game?

    - by dsaccount1
    Basically the objective is to click on certain targets, which upon doing so would destroy the target and garner you points. I've written a macro to help me until the point where its impossible to even see the target more than a mere flicker, (maybe even less than that, i cant see it with my eyes). But its possible because i believe others have done so. (Maybe on slower comps?) Anyway the question is, how would it be possible to slow down the flash game? I've thought of a couple of ways that could work but i'm not sure how to implement them. 1. Slow down the cpu speed? (smth like that? how?) 2. As the game progress the time the targets appear and stay up is reduced. Maybe theres a variable controlling all of this, isit possible to modify the address of this variable? freeze it or smth? Any ideas, suggestions and especially advice would really be appreciated, thanks!

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  • How difficult is it to write our own Robots API, similar to G Wave Robots API ? Please read the deta

    - by user169650
    Consider the following entities : a) My own Wave-server b) My own Robots API c) Tomcat d) Google wave server/any other wave server Let us consider that a and d interact with one another via Google wave federation protocol. Now, I want to write my own Robots API in Java (similar to that of G Wave Robots API) using which I want to create Robots; which I want to host in entity c), which may in-turn connect to a) for listening to events and responding with operations. Let us consider that a) is already in place, i.e. implemented. Let us also consider that the Robot running on tomcat and entity a) are co-located, so that we do not need to use JSON-RPC for receiving events/sending operations; instead we can use Java interfaces. Now, my questions are : 1.How much of an effort is it to write my own Robots API to run on a tomcat container ? 2.What are the salient points to be taken care of ? Am I missing some important point here ? 3.How can I reuse some of the classes/packages/interfaces (e.g. com.google.wave.api.AbstractRobot, com.google.wave.api.event) with little/no changes at all ?

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  • Seeking good practice advice: multisite in Drupal

    - by deanloh
    I'm using multisite to host my client sites. During development stage, I use subdomain to host the staging site, e.g. client1.mydomain.com. And here's how it look under the SITES folder: /sites/client1.mydomain.com When the site is completed and ready to go live, I created another folder for the actual domain, e.g. client1.com. Hence: /sites/client1.com Next, I created symlinks under client1.com for FILES and SETTINGS.PHP that points to the subdomain i.e. /sites/client1.com/settings.php --> /sites/client1.mydomain.com/settings.php /sites/client1.com/files --> /sites/client1.mydomain.com/files Finally, to prevent Google from indexing both the subdomain and actual domain, I created the rule in .htaccess to rewrite client1.mydomain.com to client1.com, therefore, should anyone try to access the subdomain, he will be redirected to the actual domain. This above arrangement works perfectly fine. But I somehow feel there is a better way to achieve the above in much simplified manner. Please feel free to share your views and all advice is much appreciated.

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  • Is there a Python module for handling Python object addresses?

    - by cool-RR
    (When I say "object address", I mean the string that you type in Python to access an object. For example 'life.State.step'. Most of the time, all the objects before the last dot will be packages/modules, but in some cases they can be classes or other objects.) In my Python project I often have the need to play around with object addresses. Some tasks that I have to do: Given an object, get its address. Given an address, get the object, importing any needed modules on the way. Shorten an object's address by getting rid of redundant intermediate modules. (For example, 'life.life.State.step' may be the official address of an object, but if 'life.State.step' points at the same object, I'd want to use it instead because it's shorter.) Shorten an object's address by "rooting" a specified module. (For example, 'garlicsim_lib.simpacks.prisoner.prisoner.State.step' may be the official address of an object, but I assume that the user knows where the prisoner package is, so I'd want to use 'prisoner.prisoner.State.step' as the address.) Is there a module/framework that handles things like that? I wrote a few utility modules to do these things, but if someone has already written a more mature module that does this, I'd prefer to use that. One note: Please, don't try to show me a quick implementation of these things. It's more complicated than it seems, there are plenty of gotchas, and any quick-n-dirty code will probably fail for many important cases. These kind of tasks call for battle-tested code. UPDATE: When I say "object", I mostly mean classes, modules, functions, methods, stuff like these. Sorry for not making this clear before.

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  • Effective simulation of compound poisson process in Matlab

    - by Henrik
    I need to simulate a huge bunch of compound poisson processes in Matlab on a very fine grid so I am looking to do it most effectively. I need to do a lot of simulations on the same random numbers but with parameters changing so it is practical to draw the uniforms and normals beforehand even though it means i have to draw a lot more than i will probably need and won't matter much because it will only need to be done once compared to in the order 500*n repl times the actual compound process generation. My method is the following: Let T be for how long i need to simulate and N the grid points, then my grid is: t=linspace(1,T,N); Let nrepl be the number of processes i need then I simulate P=poissrnd(lambda,nrepl,1); % Number of jumps for each replication U=(T-1)*rand(10000,nrepl)+1; % Set of uniforms on (1,T) for jump times N=randn(10000,nrepl); % Set of normals for jump size Then for replication j: Poiss=P(j); % Jumps for replication Uni=U(1:Poiss,j);% Jump times Norm=mu+sigma*N(1:Poiss,j);% Jump sizes Then this I guess is where I need your advice, I use this one-liner but it seems very slow: CPP_norm=sum(bsxfun(@times,bsxfun(@gt,t,Uni),Norm),1); In the inner for each jump it creates a series of same length as t with 0 until jump and then 1 after, multiplying this will create a grid with zeroes until jump has arrived and then the jump size and finally adding all these will produce the entire jump process on the grid. How can this be done more effectively? Thank you very much.

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  • C++: Vector of objects vs. vector of pointers to new objects?

    - by metamemetics
    Hello, I am seeking to improve my C++ skills by writing a sample software renderer. It takes objects consisting of points in a 3d space and maps them to a 2d viewport and draws circles of varying size for each point in view. Which is better: class World{ vector<ObjectBaseClass> object_list; public: void generate(){ object_list.clear(); object_list.push_back(DerivedClass1()); object_list.push_back(DerivedClass2()); or... class World{ vector<ObjectBaseClass*> object_list; public: void generate(){ object_list.clear(); object_list.push_back(new DerivedClass1()); object_list.push_back(new DerivedClass2()); ?? Would be using pointers in the 2nd example to create new objects defeat the point of using vectors, because vectors automatically call the DerivedClass destructors in the first example but not in the 2nd? Are pointers to new objects necessary when using vectors because they handle memory management themselves as long as you use their access methods? Now let's say I have another method in world: void drawfrom(Viewport& view){ for (unsigned int i=0;i<object_list.size();++i){ object_list.at(i).draw(view); } } When called this will run the draw method for every object in the world list. Let's say I want derived classes to be able to have their own versions of draw(). Would the list need to be of pointers then in order to use the method selector (-) ?

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  • User submitted content filtering

    - by Jim
    Hey all, Does anyone have any ideas on what could be used as a way to filter untrustworthy user submitted content? Take Yelp for instance, they would need to prevent competitors writing business reviews on their competitors. They would need to prevent business owners favourably reviewing their own business, or forcing friends/family to do so. They would need to prevent poor quality reviews from affecting a businesses rating and so on. I can't think what they might use to do this: Prevent multiple users from the same IP reviewing certain things Prevent business owners reviewing their own business (maybe even other businesses in the same categories as their own?) Somehow determine what a review is about and what the actual intentions behind it are Other than the first and second points, I can't think of any clever/easy way to filter potentially harmful reviews from being made available, other than a human doing it. Obviously for a site the size of Yelp this wouldn't be feasible, so what parameters could they take into consideration? Even with human intervention, how would anyone know it was the owners best buddy writing a fake review without knowing the people? I'm using this as an example in a larger study on the subject of filtering user content automatically. Does anyone have any ideas how these systems may work and what they take into consideration? Thanks!

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  • Paypal Sandbox 2014 Non US test account Sign Up proper link

    - by Flood Gravemind
    Ok I had a Paypal Sandbox account a year ago. I am developing a new site for a client and when I try to Login it won't recognize my email address. I tried forgot my password forgot password still nothing. So I guessed that maybe due to inactivity for such a long time they may have deleted my account. So then I try to Sign Up for a new one. I entered my details 3 times now and spent 6 hours trying to figure out what is the proper link to do this. Then I went to another Sandbox link which required me to entered a US Zip code and its a dead end. I am not even sure which Paypal account I signed up for those three times. No email nothing at all. I am a Non US developer and the FAQ link for Non US developers just points to their REST API. Can someone please guide me to the proper Paypal Sandbox Setup for Non US developers including the proper sign up links please. And I know Stackoverflow does not like rants but from my experience dealing with Paypal, GTA 6 should make a satirical Paypal company in their next Game with Paypal Developer Rampage mode for the main protagonist who also happens to be a Developer. EDIT: REST API does not include UK :(

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  • Pointers into elements in a container

    - by Pillsy
    Say I have an object: struct Foo { int bar_; Foo(int bar) bar_(bar) {} }; and I have an STL container that contains Foos, perhaps a vector, and I take // Elsewhere... vector<Foo> vec; vec.push_back(Foo(4)); int *p = &(vec[0].bar_) This is a terrible idea, right? The reason is that vector is going to be storing its elements in a dynamically allocated array somewhere, and eventually, if you add enough elements, it will have to allocate another array, copy over all the elements of the original array, and delete the old array. After that happens, p points to garbage. This is why many operations on a vector will invalidate iterators. It seems like it would be reasonable to assume that an operation that would invalidate iterators from a container will also invalidate pointers to data members of container elements, and that if an operation doesn't invalidate iterators, those pointers will still be safe. However, many reasonable assumptions are false. Is this one of them?

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  • Doesn't this defeat the whole purpose of having read-only properties?

    - by flockofcode
    I know how to use properties and I understand that they implicitly call underlying get and set accessors, depending on whether we are writing to or reading from a property. static void Main(string[] args) { A a = new A(); (a.b).i = 100; } class A { private B _b = new B(); public B b { get { return _b; } } } class B { public int i; } What code (a.b).i = 100; essentially does is that first property’s get accessor returns a reference to an object _b, and once we have this reference, we are able to access _b’s members and change their values. Thus, in our example, having read only property only prevents outside code from changing the value of a reference variable _b, but it doesn’t prevent outside code from accessing _b’s members. So it seems that property can only detect whether we are trying to read from or write to a variable ( in our case variable _b ) located on the stack, while it’s not able to detect whether we’re trying to also write to members of an object to which the variable on the stack ( assuming this variable is of reference type ) points to. a) But doesn’t that defeat the whole purpose of having read-only properties? Wouldn’t it be more effective if properties had the ability to also detect whether we’re trying to access members of an object returned by get accessor( assuming backing field is of a reference type )? thank you

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  • Dynamic External Program in debug tab vs2008

    - by Justin Holbrook
    I am playing with NServiceBus using the generic host; specifically I'm working on having 2 different configurations, a debug configuration that logs to the console and a release version that logs to metabase (I'm using VS2008). I had just made some code changes (commented out a logging statement), but it was still showing in the log when I ran my solution. I eventually figured out that I had switched configuration to release, made my change, then built. I think the change isn’t being picked up because in the debug tab of my project properties I have the following (abbreviated) path to the generic host: C:...\Inventory\bin\Debug\NServiceBus.Host.exe Notice it specifically points to the debug directory. So basically even though I’m in release config it’s firing up the host in the debug directory which I think is then using the dll's in the debug directory (which is why my changes didn't get picked up). I tried to come up with a workaround, but have been unsuccessful. VS Macros (like $(Configuration)) and relative pathing are not allowed here. http://connect.microsoft.com/VisualStudio/feedback/details/422223/relative-path-not-allowed-in-c-project-debug-properties-window Any ideas? I hope this doesn’t require a custom build task.

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  • A question on getting number of nodes in a Binary Tree

    - by Robert
    Dear all, I have written up two functions (pseudo code) for calculation the number of nodes and the tree height of a Binary Tree,given the root of the tree. Most importantly,the Binary Tree is represented as the First chiled/next sibling format. so struct TreeNode { Object element; TreeNode *firstChild; TreeNode *nextSibling; } Calculate the # of nodes: public int countNode(TreeNode root) { int count=0; while(root!=null) { root= root.firstChild; count++; } return count; } public int countHeight(TreeNode root) { int height=0; while(root!=null) { root= root.nextSibling; height++; } return height; } This is one of the problem I saw on an algorithm book,and my solution above seems to have some problems,also I didn't quite get the points of using this First Child/right sibling representation of Binary Tree,could you guys give me some idea and feedback,please? Cheers!

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  • lightbox dynamic image retrieval

    - by GSTAR
    I am constructing a lighbox gallery, currently experimenting with FancyBox (http://fancybox.net) and ColorBox (http://colorpowered.com/colorbox). By default you have to include a link to the large version of the image so that the Lightbox can display it. However, I am wanting to have the image link URLs pointing to a script rather than directly to the image file. So for example, instead of: <a href="mysite/images/myimage.jpg"> I want to do: <a href="mysite/photos/view/abc123"> The above URL points to a function: public function actionPhotos($view) { $photo=Photo::model()->find('name=:name', array(':name'=>$view)); if(!empty($photo)) { $user=$photo->user; $this->renderPartial('_photo', array('user'=>$user, 'photo'=>$photo, true)); } } At some point in the future the function will also update the view count of the image. Now this approach is working to an extent - most images load up but some do not load up (the lightbox gets displayed in a malformed state). I think the reason for this is because it is not processing the function quick enough. For example when I click the "next" button it needs to go to the URL, process the function and retreive/output the response. Does anybody know how I can get this working properly?

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  • Code Golf: Connecting the dots

    - by ChristopheD
    Description: The input are multiple lines (terminated by a newline) which describe a 'field'. There are 'numbers' scattered across this field: the numbers always start at 1 they follow the ordering of the natural numbers: every 'next number' is incremented with 1 every number is surrounded by (at least) one whitespace on it's left and right Task: Draw lines between these numbers in their natural order (1 -> 2 -> 3 -> ...N) with the following characteristics: replace a number with a '+' character for horizontal lines: use '-' for vertical lines: use '|' going left and down or right and up: / going left and up or right and down: \ Important note: When drawing lines of type 4 and 5 you can assume that : (given points to connect with coordinates x1, y1 and x2, y2) distance(x1,x2) == distance(y1,y2). Have a look at the examples to see where you should 'attach' the lines. It is important to follow the order in which the dots are connected (newer lines can be drawn over older lines). Sample input 1 9 10 8 7 6 5 11 13 12 3 4 14 15 16 1 2 Sample output 1 /+ / | / | +/ +--+ | +\ | \ | \+ /+ | / | /+-------------+/ +---+ / | +--+ | + | +--------------------------+ Sample input 2 4 2 3 5 6 1 8 7 Sample output 2 /+ / | / | / | /+------------------+/ +--------+\ / \ +/ +--------------------------------------+ Winner: shortest solution (by code count). Input can be read via command line.

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  • How would you structure your workflow for a web application ?

    - by cx42net
    Hi ! When designing a web application (or something else), it's good to have a workflow, and it's better to have a well ordered one. Starting with this idea in mind, I'd like to know what is your process from having an idea to maintain this great working project. For me actually, the process is the following one : Having the idea Checking this project already exists, and how it works Describing on a paper its functionalities finding a good and adequate name for this (and checking the domain availability with WHOISMyProject) Making a quick layout of the project on a paper Designing the project (via TheGimp, Photoshop, etc) Making a complete mockup of each pages Developing a prototype of the client-side application (with false datas) Developing the server side Testing Making the documentation/help/faq Releasing the project Maintaining it. Would you change the order of some points ? add/remove some ? I would please to know how you do that. I'm looking to set up a perfect workflow in order to make my project become real in the best way possible. Thank you for your opinion !

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  • Java servlet's request parameter's name set to entire json object

    - by Geren White
    I'm sending a json object through ajax to a java servlet. The json object is key-value type with three keys that point to arrays and a key that points to a single string. I build it in javascript like this: var jsonObject = {"arrayOne": arrayOne, "arrayTwo": arrayTwo, "arrayThree": arrThree, "string": stringVar}; I then send it to a java servlet using ajax as follows: httpRequest.open('POST', url, true); httpRequest.setRequestHeader("Content-type", "application/x-www-form-urlencoded"); httpRequest.setRequestHeader("Connection", "close"); var jsonString = jsonObject.toJSONString(); httpRequest.send(jsonString); This will send the string to my servlet, but It isn't showing as I expect it to. The whole json string gets set to the name of one of my request's parameters. So in my servlet if I do request.getParameterNames(); It will return an enumeration with one of the table entries' key's to be the entire object contents. I may be mistaken, but my thought was that it should set each key to a different parameter name. So I should have 4 parameters, arrayOne, arrayTwo, arrayThree, and string. Am I doing something wrong or is my thinking off here? Any help is appreciated. Thanks

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  • Adding linked table to Access 2003 while keeping ODBC connection info in MDB

    - by webworm
    I have an Access 2003 database MDB where all of the tables exist as linked tables within SQL Server 2005. The MDB file contains all of the ODBC information that points to the correct SQL Server and log-on credentials (trusted connection). What I would like to do is add a new linked table to the MDB file however I am not sure how to go about specifying the ODBC connection information. When I try to add a new linked table I keep getting prompted to locate or create a DSN file. I don't want to have to create a new DSN entry on every machine, rather I would like all that information stored within the Access MDB file itself. In the existing database I can "hover" over the table names and see the ODBC connection info as a tool-tip. All I need to do is add another linked table using the same connection information. I do have access to the SQL Server where the tables are linked to,. I have already created the new table I wanted to add. I just need to find a way to link to it.

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  • Return the Column Name for row with last non-null value "Ms Access 2007"

    - by bri1969
    I have a Table, which contains a list of league players. Each season, we record their Points per Dart. Their total PPD for that season is stored in other tables and extracted through other queries, which in turn are imported to the master table "Player History" at the end of the season for use as historical data. The current query retrieves each players PPD for each season they played, when they played last, and how many seasons played. The code for Last season Played has become too long and unstable to use. it was originally created, and split into two separate columns because a single SQL was to long. (LSP1) and LSP2) which work, but as I add seasons, Access does not like the length of code. In short, i need to find a more simple code that will look at each row, and look in that row for the last non null cell and report which column that last non null value is in. So if a player played seasons 30 & 31, but did not play 32..but did play 33, the Column with the code should be titled Last Season Played, and for that Player, it would state "33" in that cell, indicating that this player last played season "33" I will provide both tables and the query.. Please help

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  • How to document an existing small web site (web application), inside and out?

    - by Ricket
    We have a "web application" which has been developed over the past 7 months. The problem is, it was not really documented. The requirements consisted of a small bulleted list from the initial meeting 7 months ago (it's more of a "goals" statement than software requirements). It has collected a number of features which stemmed from small verbal or chat discussions. The developer is leaving very soon. He wrote the entire thing himself and he knows all of the quirks and underlying rules to each page, but nobody else really knows much more than the user interface side of it; which of course is the easy part, as it's made to be intuitive to the user. But if someone needs to repair or add a feature to it, the entire thing is a black box. The code has some minimal comments, and of course the good thing about web applications is that the address bar points you in the right direction towards fixing a problem or upgrading a page. But how should the developer go about documenting this web application? He is a bit lost as far as where to begin. As developers, how do you completely document your web applications for other developers, maintainers, and administrative-level users? What approach do you use, where do you start, do you have a template? An idea of magnitude: it uses PHP, MySQL and jQuery. It has about 20-30 main (frontend) files, along with about 15 included files and a couple folders of some assets. So overall it's a pretty small application. It interfaces with 7 MySQL tables, each one well-named, so I think the database end is pretty self-explanatory. There is a config.inc.php file with definitions of consts like the MySQL user details, some from/to emails, and URLs which PHP uses to insert into emails and pages (relative and absolute paths, basiecally). There is some AJAX via jQuery. Please comment if there is any other information that would help you help me and I will be glad to edit it in.

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  • Safe way for getting/finding a vertex in a graph with custom properties -> good programming practice

    - by Shadow
    Hi, I am writing a Graph-class using boost-graph-library. I use custom vertex and edge properties and a map to store/find the vertices/edges for a given property. I'm satisfied with how it works, so far. However, I have a small problem, where I'm not sure how to solve it "nicely". The class provides a method Vertex getVertex(Vertexproperties v_prop) and a method bool hasVertex(Vertexproperties v_prop) The question now is, would you judge this as good programming practice in C++? My opinion is, that I have first to check if something is available before I can get it. So, before getting a vertex with a desired property, one has to check if hasVertex() would return true for those properties. However, I would like to make getVertex() a bit more robust. ATM it will segfault when one would directly call getVertex() without prior checking if the graph has a corresponding vertex. A first idea was to return a NULL-pointer or a pointer that points past the last stored vertex. For the latter, I haven't found out how to do this. But even with this "robust" version, one would have to check for correctness after getting a vertex or one would also run into a SegFault when dereferencing that vertex-pointer for example. Therefore I am wondering if it is "ok" to let getVertex() SegFault if one does not check for availability beforehand?

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  • Generic factory of generic containers

    - by Feuermurmel
    I have a generic abstract class Factory<T> with a method createBoxedInstance() which returns instances of T created by implementations of createInstance() wrapped in the generic container Box<T>. abstract class Factory<T> { abstract T createInstance(); public final Box<T> createBoxedInstance() { return new Box<T>(createInstance()); } public final class Box<T> { public final T content; public Box(T content) { this.content = content; } } } At some points I need a container of type Box<S> where S is an ancestor of T. Is it possible to make createBoxedInstance() itself generic so that it will return instances of Box<S> where S is chosen by the caller? Sadly, defining the function as follows does not work as a type parameter cannot be declared using the super keyword, only used. public final <S super T> Box<S> createBoxedInstance() { return new Box<S>(createInstance()); } The only alternative I see, is to make all places that need an instance of Box<S> accept Box<? extends S> which makes the container's content member assignable to S. Is there some way around this without re-boxing the instances of T into containers of type Box<S>? (I know I could just cast the Box<T> to a Box<S> but I would feel very, very guilty.)

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