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• Need a fast programming language that can drive two printers

  - by Pete

  I have a rather unusual application that isn't working the way I need, and I hope someone here will have some suggestions or at least a direction to investigate. We have a museum exhibit that has a computer at the entrance driving two small receipt printers. There are two buttons on a console, wired to the left and right buttons of a disemboweled mouse. The two printers and associated buttons are for girls and boys, each button does a random selection from a database of names and prints a small ticket on the appropriate printer with a graphic image, a few words about the exhibit and the randomly chosen name. Conceptually all is well, but it hangs quite often. I got the project at the last minute, because the original designer got bogged down and couldn't deliver, so the exhibit's author asked me the day before opening, whether I could write something that would work. I did it in Word, since I am an experienced VBA programmer. Several other avenues I attempted first all lead to dead ends - one couldn't do graphics, another couldn't handle two printers, yet another couldn't change fonts and so on. The problem is that it simply isn't fast enough - Word can only drive one printer at a time and changing the active printer takes a long time. Not by office standards, where a second or two of delay before a printer starts working on your document is not an issue, but here I need more or less instant response. If kids press a button and nothing happens, they press it over and over until something does happen, resulting in maybe half a dozen commands being sent before the printer starts reacting. Sometimes it jams the program completely, since boys and girls will be pressing the two buttons simultaneously and Word locks up, and even when it doesn't jam, the printers then spit out a stream of tickets, making a mess. The kids start squabbling over which ticket is whose, pulling them out of the printers, snarling the paper tape, jamming the printer and generally making a mess of the whole affair, often necessitating the exhibit caretakers having to restart the computer and clear torn bits of paper out the printers. What I need is some sort of fast programming language that can drive two printers *-simultaneously-*, not the MSOffice claptrap of having to switch the active printer, that can react to both left and right mouse button click events, can print a small graphic image and can print in different font sizes and styles and. I don't need many, but it's not all in one typeface. Can anyone suggest what I might use for this? I don't even know if it's possible at all under Windows, whether the "single active printer" garbage is an Office artifact, or a Windows restriction. My little Commodore-64 twenty-five years ago had two printers attached to it and drove both simultaneously with no difficulties - it doesn't seem to me it should be such an impossible requirement today.

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• Generating custom-form documents from base-form plus XML?

  - by KlaymenDK

  Hi all, this is my first stack overflow, and it's a complex one. Sorry. My task is to generate custom documents from a basic template plus some XML without having a custom form design element for each case. Here's the whole picture: We are building a Lotus Notes (client, not web) application for world-wide application access control; the scope is something like 400.000 users being able to request access to any of 1000+ applications. Each application needs its own request form -- different number of approvers, various info required, that sort of thing. We simply can't have a thousand forms in a database (one per application), and anyway their maintenance really needs to be pushed from the developers to the application owners. So instead of custom forms, we'd like to create a generic "template" form that stores a block of basic fields, but then allows application owners to define another block of fields dynamically -- "I want a mandatory plain-text field named 'Name' here, and then a date field named 'Due' here that must be later than today's date, and then ...". I hope this makes sense (if not, think of it as a generic questionnaire application). I pretty much have the structure in place for designing the dynamic fields (form builder GUI - XML-encoded data - pre-rendered DXL for injecting into a form), including mark-up for field types, value options, and rudimentary field validation instructions. My problem is generating a document with this dynamic content injected at the proper location (without needing a custom form design element for each case). Doing the dynamic content via HTML is out. The Notes client web rendering is simply way too poor, and it would be quite a challenge to implement things like field validation instructions, date selectors, and name look-ups. DXL, on the other hand, would allow us to use native Notes fields and code. As a tech demo, I've managed to implement a custom form generator that injects the pre-rendered DXL for the dynamic content into a base form; but as I said, we don't want a ton of custom form design elements. I've tried to implement a way to create a document with the "store form in document" flag set, but once I've created the document from the base form, I can't get DXL access to the stored form design, and so I can't inject my dynamic content. I know this is not something Notes was ever intended to do. Has anyone ever tried something like it (and gotten away with it)? Thanks for reading this far. With a boatload of thanks in advance, Jan Gundtofte-Bruun

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• Is this implementation truely tail-recursive?

  - by CFP

  Hello everyone! I've come up with the following code to compute in a tail-recursive way the result of an expression such as 3 4 * 1 + cos 8 * (aka 8*cos(1+(3*4))) The code is in OCaml. I'm using a list refto emulate a stack. type token = Num of float | Fun of (float->float) | Op of (float->float->float);; let pop l = let top = (List.hd !l) in l := List.tl (!l); top;; let push x l = l := (x::!l);; let empty l = (l = []);; let pile = ref [];; let eval data = let stack = ref data in let rec _eval cont = match (pop stack) with | Num(n) -> cont n; | Fun(f) -> _eval (fun x -> cont (f x)); | Op(op) -> _eval (fun x -> cont (op x (_eval (fun y->y)))); in _eval (fun x->x) ;; eval [Fun(fun x -> x**2.); Op(fun x y -> x+.y); Num(1.); Num(3.)];; I've used continuations to ensure tail-recursion, but since my stack implements some sort of a tree, and therefore provides quite a bad interface to what should be handled as a disjoint union type, the call to my function to evaluate the left branch with an identity continuation somehow irks a little. Yet it's working perfectly, but I have the feeling than in calling the _eval (fun y->y) bit, there must be something wrong happening, since it doesn't seem that this call can replace the previous one in the stack structure... Am I misunderstanding something here? I mean, I understand that with only the first call to _eval there wouldn't be any problem optimizing the calls, but here it seems to me that evaluation the _eval (fun y->y) will require to be stacked up, and therefore will fill the stack, possibly leading to an overflow... Thanks!

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• Paypal IPN: how get the POSTs from this class?

  - by sineverba

  I'm using this Class <?php class paypalIPN { //sandbox: private $paypal_url = 'https://www.sandbox.paypal.com/cgi-bin/webscr'; //live site: //private $paypal_url = 'https://www.paypal.com/cgi-bin/webscr'; private $data = null; public function __construct() { $this->data = new stdClass; } public function isa_dispute() { //is it some sort of dispute. return $this->data->txn_type == "new_case"; } public function validate() { // parse the paypal URL $response = ""; $url_parsed = parse_url($this->paypal_url); // generate the post string from the _POST vars aswell as load the // _POST vars into an arry so we can play with them from the calling // script. $post_string = ''; foreach ($_POST as $field=>$value) { $this->data->$field = $value; $post_string .= $field.'='.urlencode(stripslashes($value)).'&'; } $post_string.="cmd=_notify-validate"; // append ipn command $ch = curl_init(); curl_setopt($ch, CURLOPT_URL, $this->paypal_url); //curl_setopt($ch, CURLOPT_VERBOSE, 1); //keep the peer and server verification on, recommended //(can switch off if getting errors, turn to false) curl_setopt($ch, CURLOPT_SSL_VERIFYPEER, FALSE); curl_setopt($ch, CURLOPT_SSL_VERIFYHOST, FALSE); curl_setopt($ch, CURLOPT_RETURNTRANSFER,1); curl_setopt($ch, CURLOPT_POST, 1); curl_setopt($ch, CURLOPT_POSTFIELDS, $post_string); $response = curl_exec($ch); if (curl_errno($ch)) { die("Curl Error: " . curl_errno($ch) . ": " . curl_error($ch)); } curl_close($ch); return $response; if (preg_match("/VERIFIED/", $response)) { // Valid IPN transaction. return $this->data; } else { return false; } } } ANd i recall in this mode: public function get_ipn() { $ipn = new paypalIPN(); $result = $ipn->validate(); $logger = new Log('/error.log'); $logger->write(print_r($result)); } But I obtain only "VERIFIED" or "1" (whitout or with the print_r function). I just tried also to return directly the raw curl response with return $response; or return $this->response; or also return $this->parse_string; but everytime I receive only "1" or "VERIFIED"....... Thank you very much

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• C++: Templates for static functions?

  - by Rosarch

  I have a static Utils class. I want certain methods to be templated, but not the entire class. How do I do this? This fails: #pragma once #include <string> using std::string; class Utils { private: template<class InputIterator, class Predicate> static set<char> findAll_if_rec(InputIterator begin, InputIterator end, Predicate pred, set<char> result); public: static void PrintLine(const string& line, int tabLevel = 0); static string getTabs(int tabLevel); template<class InputIterator, class Predicate> static set<char> Utils::findAll_if(InputIterator begin, InputIterator end, Predicate pred); }; Error: utils.h(10): error C2143: syntax error : missing ';' before '<' utils.h(10): error C4430: missing type specifier - int assumed. Note: C++ does not support default-int utils.h(10): error C4430: missing type specifier - int assumed. Note: C++ does not support default-int utils.h(10): error C2238: unexpected token(s) preceding ';' utils.h(10): error C2988: unrecognizable template declaration/definition utils.h(10): error C2059: syntax error : '<' What am I doing wrong? What is the correct syntax for this? Incidentally, I'd like to templatize the return value, too. So instead of: template<class InputIterator, class Predicate> static set<char> findAll_if_rec(InputIterator begin, InputIterator end, Predicate pred, set<char> result); I'd have: template<class return_t, class InputIterator, class Predicate> static return_t findAll_if_rec(InputIterator begin, InputIterator end, Predicate pred, set<char> result); How would I specify that: 1) return_t must be a set of some sort 2) InputIterator must be an iterator 3) InputIterator's type must work with return_t's type. Thanks.

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• highlight query string in more than one field using solr search feature

  - by Romi

  i am using solr indexes for showing my search results. to show serch results i am parsing json data received from solr. i am able to highlight a query string in search result but only in a single field. for this i set hl=true and hl.fl="field1". i did it as $.getJSON("http://192.168.1.9:8983/solr/db/select/?wt=json&&start=0&rows=100&q="+lowerCaseQuery+"&hl=true&hl.fl=description,name&hl.usePhraseHighlighter=true&sort=price asc&json.wrf=?", function(result){ var n=result.response.numFound var highlight = new Array(n); $.each(result.highlighting, function(i, hitem){ var match = hitem.text[0].match(/<em>(.*?)<\/em>/); highlight[i]=match[1]; }); $.each(newresult.response.docs, function(i,item){ var word=highlight[item["UID_PK"]]; var result = item.text[0].replace(new RegExp(word,'g'), '<em>' + word + '</em>'); }); for this json object is as : { "responseHeader": { "status": 0, "QTime": 32 }, "response": { "numFound": 21, "start": 0, "docs": [ { "description": "The matte finish waves on this wedding band contrast with the high polish borders. This sharp and elegant design was finely crafted in Japan.", "UID_PK": "8252", }, { "description": "This elegant ring has an Akoya cultured pearl with a band of bezel-set round diamonds making it perfect for her to wear to work or the night out.", "UID_PK": "8142", }, ] }, "highlighting": { "8252": { "description": [ " and <em>elegant</em> design was finely crafted in Japan." ] }, "8142": { "description": [ "This <em>elegant</em> ring has an Akoya cultured pearl with a band of bezel-set round diamonds making" ] }, } } Now if i want to highlight query string in two fields i did as hl=true hl.fl=descrption, name my json is as: { "responseHeader":{ "status":0, "QTime":16 }, "response":{ "numFound":1904, "start":0, "docs":[ { "description":"", "UID_PK":"7780", "name":[ "Diamond bracelet with Milgrain Bezel1" ] }, { "description":"This pendant is sure to win hearts. Round diamonds form a simple and graceful line.", "UID_PK":"8121", "name":[ "Heartline Diamond Pendant" ] }, "highlighting":{ "7780":{ "name":[ "<em>Diamond</em> bracelet with Milgrain Bezel1" ] }, "8121":{ "description":[ "This pendant is sure to win hearts. Round <em>diamonds</em> form a simple and graceful line." ], "name":[ "Heartline <em>Diamond</em> Pendant" ] } } } Now how should i parse it to get the result. suggest me some general technique, so if i want to highlight query in more fields then i could do so. Thanks

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• Parallel programming in C#

  - by Alxandr

  I'm interested in learning about parallel programming in C#.NET (not like everything there is to know, but the basics and maybe some good-practices), therefore I've decided to reprogram an old program of mine which is called ImageSyncer. ImageSyncer is a really simple program, all it does is to scan trough a folder and find all files ending with .jpg, then it calculates the new position of the files based on the date they were taken (parsing of xif-data, or whatever it's called). After a location has been generated the program checks for any existing files at that location, and if one exist it looks at the last write-time of both the file to copy, and the file "in its way". If those are equal the file is skipped. If not a md5 checksum of both files is created and matched. If there is no match the file to be copied is given a new location to be copied to (for instance, if it was to be copied to "C:\test.jpg" it's copied to "C:\test(1).jpg" instead). The result of this operation is populated into a queue of a struct-type that contains two strings, the original file and the position to copy it to. Then that queue is iterated over untill it is empty and the files are copied. In other words there are 4 operations: 1. Scan directory for jpegs 2. Parse files for xif and generate copy-location 3. Check for file existence and if needed generate new path 4. Copy files And so I want to rewrite this program to make it paralell and be able to perform several of the operations at the same time, and I was wondering what the best way to achieve that would be. I've came up with two different models I can think of, but neither one of them might be any good at all. The first one is to parallelize the 4 steps of the old program, so that when step one is to be executed it's done on several threads, and when the entire of step 1 is finished step 2 is began. The other one (which I find more interesting because I have no idea of how to do that) is to create a sort of worker and consumer model, so when a thread is finished with step 1 another one takes over and performs step 2 at that object (or something like that). But as said, I don't know if any of these are any good solutions. Also, I don't know much about parallel programming at all. I know how to make a thread, and how to make it perform a function taking in an object as its only parameter, and I've also used the BackgroundWorker-class on one occasion, but I'm not that familiar with any of them. Any input would be appreciated.

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• Mocking methods that call other methods Still hit database.Can I avoid it?

  - by devnet247

  Hi, It has been decided to write some unit tests using moq etc..It's lots of legacy code c# (this is beyond my control so cannot answer the whys of this) Now how do you cope with a scenario when you dont want to hit the database but you indirectly still hit the database? This is something I put together it's not the real code but gives you an idea. How would you deal with this sort of scenario? Basically calling a method on a mocked interface still makes a dal call as inside that method there are other methods not part of that interface?Hope it's clear [TestFixture] public class Can_Test_this_legacy_code { [Test] public void Should_be_able_to_mock_login() { var mock = new Mock<ILoginDal>(); User user; var userName = "Jo"; var password = "password"; mock.Setup(x => x.login(It.IsAny<string>(), It.IsAny<string>(),out user)); var bizLogin = new BizLogin(mock.Object); bizLogin.Login(userName, password, out user); } } public class BizLogin { private readonly ILoginDal _login; public BizLogin(ILoginDal login) { _login = login; } public void Login(string userName, string password, out User user) { //Even if I dont want to this will call the DAL!!!!! var bizPermission = new BizPermission(); var permissionList = bizPermission.GetPermissions(userName); //Method I am actually testing _login.login(userName,password,out user); } } public class BizPermission { public List<Permission>GetPermissions(string userName) { var dal=new PermissionDal(); var permissionlist= dal.GetPermissions(userName); return permissionlist; } } public class PermissionDal { public List<Permission> GetPermissions(string userName) { //I SHOULD NOT BE GETTING HERE!!!!!! return new List<Permission>(); } } public interface ILoginDal { void login(string userName, string password,out User user); } public interface IOtherStuffDal { List<Permission> GetPermissions(); } public class Permission { public int Id { get; set; } public string Name { get; set; } } Any suggestions? Am I missing the obvious? Is this Untestable code? Very very grateful for any suggestions.

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• How to handle environment-specific application configuration organization-wide?

  - by Stuart Lange

  Problem Your organization has many separate applications, some of which interact with each other (to form "systems"). You need to deploy these applications to separate environments to facilitate staged testing (for example, DEV, QA, UAT, PROD). A given application needs to be configured slightly differently in each environment (each environment has a separate database, for example). You want this re-configuration to be handled by some sort of automated mechanism so that your release managers don't have to manually configure each application every time it is deployed to a different environment. Desired Features I would like to design an organization-wide configuration solution with the following properties (ideally): Supports "one click" deployments (only the environment needs to be specified, and no manual re-configuration during/after deployment should be necessary). There should be a single "system of record" where a shared environment-dependent property is specified (such as a database connection string that is shared by many applications). Supports re-configuration of deployed applications (in the event that an environment-specific property needs to change), ideally without requiring a re-deployment of the application. Allows an application to be run on the same machine, but in different environments (run a PROD instance and a DEV instance simultaneously). Possible Solutions I see two basic directions in which a solution could go: Make all applications "environment aware". You would pass the environment name (DEV, QA, etc) at the command line to the app, and then the app is "smart" enough to figure out the environment-specific configuration values at run-time. The app could fetch the values from flat files deployed along with the app, or from a central configuration service. Applications are not "smart" as they are in #1, and simply fetch configuration by property name from config files deployed with the app. The values of these properties are injected into the config files at deploy-time by the install program/script. That install script takes the environment name and fetches all relevant configuration values from a central configuration service. Question How would/have you achieved a configuration solution that solves these problems and supports these desired features? Am I on target with the two possible solutions? Do you have a preference between those solutions? Also, please feel free to tell me that I'm thinking about the problem all wrong. Any feedback would be greatly appreciated.

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• opacity in ie using absolutely positioned divs not working

  - by camomileCase

  I've been banging my head against the wall for a few hours how trying to sort this out. I'm trying to position one div on top of another for the purpose of fading one in on top of the other. The divs will have an image and some other html in them. I cannot get opacity to work in ie8. I've simplified my html as much as possible: <!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN" "http://www.w3.org/TR/html4/strict.dtd"> <html> <head> <style> * { margin: 0; padding: 0; } .carousel-container { position: relative; } .carousel-overlay { position: absolute; } #carousel-container-a { opacity: 1; -ms-filter: "progid:DXImageTransform.Microsoft.Alpha(Opacity=100)"; filter: progid:DXImageTransform.Microsoft.Alpha(Opacity=100); } #carousel-container-b { opacity: 0; -ms-filter: "progid:DXImageTransform.Microsoft.Alpha(Opacity=0)"; filter: progid:DXImageTransform.Microsoft.Alpha(Opacity=0); } h1 { font-size: 100px; } </style> </head> <body> <div id="carousel-container-a" class="carousel-container"> <div class="carousel-overlay" style="left: 10px; top: 10px;"> <h1 style="color: black;">Showcase</h1> </div> <!-- other elements removed for simplicity --> </div> <div id="carousel-container-b" class="carousel-container"> <div class="carousel-overlay" style="left: 20px; top: 20px;"> <h1 style="color: red;">Welcome</h1> </div> <!-- other elements removed for simplicity --> </div> </body> </html> Why doesn't the opacity work? How can I make it work?

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• Makefile issue with compiling a C++ program

  - by Steve

  I recently got MySQL compiled and working on Cygwin, and got a simple test example from online to verify that it worked. The test example compiled and ran successfully. However, when incorporating MySQL in a hobby project of mine it isn't compiling which I believe is due to how the Makefile is setup, I have no experience with Makefiles and after reading tutorials about them, I have a better grasp but still can't get it working correctly. When I try and compile my hobby project I recieve errors such as: Obj/Database.o:Database.cpp:(.text+0x492): undefined reference to `_mysql_insert_id' Obj/Database.o:Database.cpp:(.text+0x4c1): undefined reference to `_mysql_affected_rows' collect2: ld returned 1 exit status make[1]: *** [build] Error 1 make: *** [all] Error 2 Here is my Makefile, it worked with compiling and building the source before I attempted to put in MySQL support into the project. The LIBMYSQL paths are correct, verified by 'mysql_config'. COMPILER = g++ WARNING1 = -Wall -Werror -Wformat-security -Winline -Wshadow -Wpointer-arith WARNING2 = -Wcast-align -Wcast-qual -Wredundant-decls LIBMYSQL = -I/usr/local/include/mysql -L/usr/local/lib/mysql -lmysqlclient DEBUGGER = -g3 OPTIMISE = -O C_FLAGS = $(OPTIMISE) $(DEBUGGER) $(WARNING1) $(WARNING2) -export-dynamic $(LIBMYSQL) L_FLAGS = -lz -lm -lpthread -lcrypt $(LIBMYSQL) OBJ_DIR = Obj/ SRC_DIR = Source/ MUD_EXE = project MUD_DIR = TestP/ LOG_DIR = $(MUD_DIR)Files/Logs/ ECHOCMD = echo -e L_GREEN = \e[1;32m L_WHITE = \e[1;37m L_BLUE = \e[1;34m L_RED = \e[1;31m L_NRM = \e[0;00m DATE = `date +%d-%m-%Y` FILES = $(wildcard $(SRC_DIR)*.cpp) C_FILES = $(sort $(FILES)) O_FILES = $(patsubst $(SRC_DIR)%.cpp, $(OBJ_DIR)%.o, $(C_FILES)) all: @$(ECHOCMD) " Compiling $(L_RED)$(MUD_EXE)$(L_NRM)."; @$(MAKE) -s build build: $(O_FILES) @rm -f $(MUD_EXE) $(COMPILER) -o $(MUD_EXE) $(L_FLAGS) $(O_FILES) @echo " Finished Compiling $(MUD_EXE)."; @chmod g+w $(MUD_EXE) @chmod a+x $(MUD_EXE) @chmod g+w $(O_FILES) $(OBJ_DIR)%.o: $(SRC_DIR)%.cpp @echo " Compiling $@"; $(COMPILER) -c $(C_FLAGS) $< -o $@ .cpp.o: $(COMPILER) -c $(C_FLAGS) $< clean: @echo " Complete compile on $(MUD_EXE)."; @rm -f $(OBJ_DIR)*.o $(MUD_EXE) @$(MAKE) -s build I like the functionality of the Makefile, instead of spitting out all the arguments etc, it just spits out the "Compiling [Filename]" etc. If I add -c to the L_FLAGS then it compiles (I think) but instead spits out stuff like: g++: Obj/Database.o: linker input file unused because linking not done After a full day of trying and research on google, I'm no closer to solving my problem, so I come to you guys to see if you can explain to me why all this is happening and if possible, steps to solve. Regards, Steve

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• Reading three words and sorting them in lexicographic order

  - by Derrick

  I am trying to create a program that asks the User to type three words and sort them in lexicographic order. EXAMPLE; Enter three words separated by spaces: Pear Orange Apple Apple Orange Pear The program is working fine (if I attempt the above example) except for one type of combination example that I will show below. EXAMPLE; Enter three words separated by spaces: Orange Apple Pear Apple Pear Pear The program is skipping the first word (Orange) if it is supposed to appear in the middle of the three words. I believe that this line of code is affecting the program because it says that "this assigned value is never used" but I'm not sure how to fix it since I'm still an entry Java learner. middle = firstWord; Because of that line being unused, it's why Pear appeared twice. import java.util.*; public static void main(String[] args) { Scanner wordInput = new Scanner(System.in); String firstWord; String secondWord; String thirdWord; System.out.println("Enter three words separated by spaces: "); firstWord = wordInput.next(); secondWord = wordInput.next(); thirdWord = wordInput.next(); String top = firstWord; String bottom = firstWord; if( top.compareTo(secondWord) > 0) { top = secondWord; } if( top.compareTo(thirdWord) > 0) { top = thirdWord; } if( bottom.compareTo(secondWord) < 0) { bottom = secondWord; } if( bottom.compareTo(thirdWord) < 0) { bottom = thirdWord; } String middle; if( !firstWord.equals(bottom) && !firstWord.equals(top) ) { middle = firstWord; } if( !secondWord.equals(bottom) && !secondWord.equals(top) ) { middle = secondWord; } else { middle = thirdWord; } System.out.println( top ); System.out.println( middle ); System.out.println( bottom ); } } Does anyone what I am missing or doing wrong? :( Please and thank you for any help!

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• Basic Custom String Class for C++

  - by wdow88

  Hey all, I'm working on building my own string class with very basic functionality. I am having difficulty understand what is going on with the basic class that I have define, and believe there is some sort of error dealing with the scope occurring. When I try to view the objects I created, all the fields are described as (obviously bad pointer). Also, if I make the data fields public or build an accessor method, the program crashes. For some reason the pointer for the object is 0xccccccccc which points to no where. How can a I fix this? Any help/comments are much appreciated. //This is a custom string class, so far the only functions are //constructing and appending #include<iostream> using namespace std; class MyString1 { public: MyString1() { //no arg constructor char *string; string = new char[0]; string[0] ='\0'; std::cout << string; size = 1; } //constructor receives pointer to character array MyString1(char* chars) { int index = 0; //Determine the length of the array while (chars[index] != NULL) index++; //Allocate dynamic memory on the heap char *string; string = new char[index+1]; //Copy the contents of the array pointed by chars into string, the char array of the object for (int ii = 0; ii < index; ii++) string[ii] = chars[ii]; string[index+1] = '\0'; size = index+1; } MyString1 append(MyString1 s) { //determine new size of the appended array and allocate memory int newsize = s.size + size; MyString1 MyString2; char *newstring; newstring = new char[newsize+1]; int index = 0; //load the first string into the array while (string[index] != NULL) { newstring[index] = string[index]; index++; } //load the second string while (s.string[index] != NULL) { newstring[index] = s.string[index]; index++; } //null terminate newstring[newsize+1] = '\0'; delete string; //generate the object for return MyString2.string=newstring; MyString2.size=newsize; return MyString2; } private: char *string; int size; }; int main() { MyString1 string1; MyString1 string2("Hello There"); MyString1 string3("Buddy"); string2.append(string3); return 0; }

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• Release management with a distributed version control system

  - by See Sharp Cheddar

  We're considering a switch from SVN to a distributed VCS at my workplace. I'm familiar with all the reasons for wanting to using a DVCS for day-to-day development: local version control, easier branching and merging, etc., but I haven't seen that much that's compelling in terms of managing software releases. Here's our release process: Discover what changes are available for merging. Run a query to find the defects/tickets associated with these changes. Filter out changes associated with "open" tickets. In our environment, tickets must be in a closed state in order to merged with a release branch. Filter out changes we don't want in the release branch. We are very conservative when it comes to merging changes. If a change isn't absolutely necessary, it doesn't get merged. Merge available changes, preferably in chronological order. We group changes together if they're associated with the same ticket. Block unwanted changes from the release branch (svnmerge block) so we don't have to deal with them again. Sometimes we can be juggling 3-5 different milestones at a time. Some milestones have very different constraints, and the block list can get quite long. I've been messing around with git, mercurial and plastic, and as far as I can tell none of them address this model very well. It seems like they would work very well when you have only one product you're releasing, but I can't imagine using them for juggling multiple, very different products from the same codebase. For example, cherry-picking seems to be an afterthought in mercurial. (You have to use the 'transplant' command). After you cherry-pick a change into a branch it still shows up as an available integration. Cherry-picking breaks the mercurial way of working. DVCS seems to be better suited for feature branches. There's no need for cherry-picking if you merge directly from a feature branch to trunk and the release branch. But who wants to do all that merging all the time? And how do you query for what's available to merge? And how do you make sure all the changes in a feature branch belong together? It sounds like total chaos. I'm torn because the coder in me wants DVCS for day-to-day work. I really want it. But I fear the day when I have to put the release manager hat and sort out what needs to be merged and what doesn't. I want to write code, I don't want to be a merge monkey.

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• User has many computers, computers have many attributes in different tables, best way to JOIN?

  - by krismeld

  I have a table for users: USERS: ID | NAME | ---------------- 1 | JOHN | 2 | STEVE | a table for computers: COMPUTERS: ID | USER_ID | ------------------ 13 | 1 | 14 | 1 | a table for processors: PROCESSORS: ID | NAME | --------------------------- 27 | PROCESSOR TYPE 1 | 28 | PROCESSOR TYPE 2 | and a table for harddrives: HARDDRIVES: ID | NAME | ---------------------------| 35 | HARDDRIVE TYPE 25 | 36 | HARDDRIVE TYPE 90 | Each computer can have many attributes from the different attributes tables (processors, harddrives etc), so I have intersection tables like this, to link the attributes to the computers: COMPUTER_PROCESSORS: C_ID | P_ID | --------------| 13 | 27 | 13 | 28 | 14 | 27 | COMPUTER_HARDDRIVES: C_ID | H_ID | --------------| 13 | 35 | So user JOHN, with id 1 owns computer 13 and 14. Computer 13 has processor 27 and 28, and computer 13 has harddrive 35. Computer 14 has processor 27 and no harddrive. Given a user's id, I would like to retrieve a list of that user's computers with each computers attributes. I have figured out a query that gives me a somewhat of a result: SELECT computers.id, processors.id AS p_id, processors.name AS p_name, harddrives.id AS h_id, harddrives.name AS h_name, FROM computers JOIN computer_processors ON (computer_processors.c_id = computers.id) JOIN processors ON (processors.id = computer_processors.p_id) JOIN computer_harddrives ON (computer_harddrives.c_id = computers.id) JOIN harddrives ON (harddrives.id = computer_harddrives.h_id) WHERE computers.user_id = 1 Result: ID | P_ID | P_NAME | H_ID | H_NAME | ----------------------------------------------------------- 13 | 27 | PROCESSOR TYPE 1 | 35 | HARDDRIVE TYPE 25 | 13 | 28 | PROCESSOR TYPE 2 | 35 | HARDDRIVE TYPE 25 | But this has several problems... Computer 14 doesnt show up, because it has no harddrive. Can I somehow make an OUTER JOIN to make sure that all computers show up, even if there a some attributes they don't have? Computer 13 shows up twice, with the same harddrive listet for both. When more attributes are added to a computer (like 3 blocks of ram), the number of rows returned for that computer gets pretty big, and it makes it had to sort the result out in application code. Can I somehow make a query, that groups the two returned rows together? Or a query that returns NULL in the h_name column in the second row, so that all values returned are unique? EDIT: What I would like to return is something like this: ID | P_ID | P_NAME | H_ID | H_NAME | ----------------------------------------------------------- 13 | 27 | PROCESSOR TYPE 1 | 35 | HARDDRIVE TYPE 25 | 13 | 28 | PROCESSOR TYPE 2 | 35 | NULL | 14 | 27 | PROCESSOR TYPE 1 | NULL | NULL | Or whatever result that make it easy to turn it into an array like this [13] => [P_NAME] => [0] => PROCESSOR TYPE 1 [1] => PROCESSOR TYPE 2 [H_NAME] => [0] => HARDDRIVE TYPE 25 [14] => [P_NAME] => [0] => PROCESSOR TYPE 1

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• Working with friends. Poor career choice?

  - by a_person

  Hi all, Hope you can help me solve somewhat of a moral dilemma. Some time ago, after just a few years of living in U.S. and having to take any job I could get my hands on a friend of mine submitted recommended me for an open position at the company that he was working for. I could have not been happier. I do not have a degree of any sort, however, by being passionate about CS and with constant drive for self education I've became a somewhat of a strong generalist. Every place I worked for recognized me for that quality and used me on various projects where set of technology in hand had no overlap with set of knowledge of the team members. Rapidly I've advanced to Sr. Programmer position and the trend of me following a friend from one place to another have started and continued on for a few years. My friend's goal always been to become an IT Director, mine is to become the best programmer I can be. To my knowledge I've accommodated his goals as much as I could by taking a back seat, and letting him take the lead. Fast forward to today. He's a manager, and I am on his team. I am unhappy and I in considerable amount of suffering. I am not being utilized to my potential, it's almost exact opposite, I am being micromanaged to an unhealthy extent, my decisions, and suggestions are constantly met with negative connotation. Last week I had to hear about how my friend is a better programmer than I am. My ego was ecstatic about this one /s. In addition to that working in the field of BI have exhausted itself for most parts. The only pleasure of my work is being derived from making everything as dynamic and parameter driven as possible. This is the only area where a friend of mine does not feel competent enough to actually micromanage. Because of my situation I feel a fair amount of guilt and ever growing resentment. I need your advice, maybe you've dealt with this expression of ego before, needs of self vs the needs of your friend. Is working with a friend a poor choice? Thank you for reading in.

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• Debugging a basic OpenGL texture fail? (iphone)

  - by Ben

  Hey all, I have a very basic texture map problem in GL on iPhone, and I'm wondering what strategies there are for debugging this kind of thing. (Frankly, just staring at state machine calls and wondering if any of them is wrong or misordered is no way to live-- are there tools for this?) I have a 512x512 PNG file that I'm loading up from disk (not specially packed), creating a CGBitmapContext, then calling CGContextDrawImage to get bytes out of it. (This code is essentially stolen from an Apple sample.) I'm trying to map the texture to a "quad", with code that looks essentially like this-- all flat 2D stuff, nothing fancy: glEnable(GL_TEXTURE_2D); glTexEnvf(GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, GL_MODULATE); glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_REPEAT); glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_REPEAT); glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR); glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR); glEnableClientState(GL_TEXTURE_COORD_ARRAY); GLfloat vertices[8] = { viewRect.origin.x, viewRect.size.height, viewRect.origin.x, viewRect.origin.y, viewRect.size.width, viewRect.origin.y, viewRect.size.width, viewRect.size.height }; GLfloat texCoords[8] = { 0, 1.0, 0, 0, 1.0, 0, 1.0, 1.0 }; glBindTexture(GL_TEXTURE_2D, myTextureRef); // This was previously bound to glVertexPointer(2, GL_FLOAT , 0, vertices); glTexCoordPointer(2, GL_FLOAT, 0, texCoords); glDrawArrays(GL_TRIANGLE_FAN, 0, 4); glDisableClientState(GL_TEXTURE_COORD_ARRAY); glDisable(GL_TEXTURE_2D); My supposedly textured area comes out just black. I see no debug output from the CG calls to set up the texture. glGetError reports nothing. If I simplify this code block to just draw the verts, but set up a pure color, the quad area lights up exactly as expected. If I clear the whole context immediately beforehand to red, I don't see the red-- which means something is being rendered there, but not the contents of my PNG. What could I be doing wrong? And more importantly, what are the right tools and techniques for debugging this sort of thing, because running into this kind of problem and not being able to "step through it" in a debugger in any meaningful way is a bummer. Thanks!

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• dynamic module creation

  - by intuited

  I'd like to dynamically create a module from a dictionary, and I'm wondering if adding an element to sys.modules is really the best way to do this. EG context = { a: 1, b: 2 } import types test_context_module = types.ModuleType('TestContext', 'Module created to provide a context for tests') test_context_module.__dict__.update(context) import sys sys.modules['TestContext'] = test_context_module My immediate goal in this regard is to be able to provide a context for timing test execution: import timeit timeit.Timer('a + b', 'from TestContext import *') It seems that there are other ways to do this, since the Timer constructor takes objects as well as strings. I'm still interested in learning how to do this though, since a) it has other potential applications; and b) I'm not sure exactly how to use objects with the Timer constructor; doing so may prove to be less appropriate than this approach in some circumstances. EDITS/REVELATIONS/PHOOEYS/EUREKAE: I've realized that the example code relating to running timing tests won't actually work, because import * only works at the module level, and the context in which that statement is executed is that of a function in the testit module. In other words, the globals dictionary used when executing that code is that of main, since that's where I was when I wrote the code in the interactive shell. So that rationale for figuring this out is a bit botched, but it's still a valid question. I've discovered that the code run in the first set of examples has the undesirable effect that the namespace in which the newly created module's code executes is that of the module in which it was declared, not its own module. This is like way weird, and could lead to all sorts of unexpected rattlesnakeic sketchiness. So I'm pretty sure that this is not how this sort of thing is meant to be done, if it is in fact something that the Guido doth shine upon. The similar-but-subtly-different case of dynamically loading a module from a file that is not in python's include path is quite easily accomplished using imp.load_source('NewModuleName', 'path/to/module/module_to_load.py'). This does load the module into sys.modules. However this doesn't really answer my question, because really, what if you're running python on an embedded platform with no filesystem? I'm battling a considerable case of information overload at the moment, so I could be mistaken, but there doesn't seem to be anything in the imp module that's capable of this. But the question, essentially, at this point is how to set the global (ie module) context for an object. Maybe I should ask that more specifically? And at a larger scope, how to get Python to do this while shoehorning objects into a given module?

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• jQuery to hide and show divs with an indicator

  - by songdogtech

  Using the jQuery below to toggle the hiding and showing of divs of text: how would I add some sort of indicator - like an up and down arrow as a graphic - to the titles when the divs are either open and closed? What's the best way to do that? Two images? A CSS sprite? And most importantly: how would that be integrated into the JS? I've looked at other jQuery that assigns a random number to each div and then determines which are open and which are closed and toggles one of two images. But I'm using php in a WordPress loop to show a posts, and that gives problems with incrementing in the loop, so there must be an easier way that doesn't require changes in the name of the title div. Thanks.... This JS fires the showing and hiding. Each div can be expanded and collapsed independently. $(document).ready(function() { $('div.demo-show:eq(0)> div').hide(); $('div.demo-show:eq(0)> h3').click(function() { $(this).next().slideToggle('fast'); }); }); This is the HTML it works with: <div class="collapser"> <p class="title">Header-1 </p> <div class="contents">Lorem ipsum</div> <p class="title">Header-2</p> <div class="contents">Lorem ipsum </div> <p class="title">Header-3</p> <div class="contents">Lorem ipsum</div> </div> The CSS is arbitrary: .collapser { margin: 0; padding: 0; width: 500px; } .title { margin: 1px; color: #fff; padding: 3px 10px; cursor: pointer; position: relative; background-color:#c30; } .contents { padding: 5px 10px; background-color:#fafafa; }

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• Format form fields for bootstrap using rails+nokogiri

  - by user1116573

  I have the following in an initializer in a rails app that uses Twitter bootstrap so that it removes the div.field_with_errors that rails applies when validation fails on a field but also the initializer adds the help/validation text after the erroneous input field: require 'nokogiri' ActionView::Base.field_error_proc = Proc.new do |html_tag, instance| html = %(<div class="field_with_errors">#{html_tag}</div>).html_safe form_fields = [ 'textarea', 'input', 'select' ] elements = Nokogiri::HTML::DocumentFragment.parse(html_tag).css("label, " + form_fields.join(', ')) elements.each do |e| if e.node_name.eql? 'label' html = %(#{e}).html_safe elsif form_fields.include? e.node_name if instance.error_message.kind_of?(Array) html = %(#{e}<span class="help-inline">&nbsp;#{instance.error_message.join(',')}</span>).html_safe else html = %(#{e}<span class="help-inline">&nbsp;#{instance.error_message}</span>).html_safe end end end html end This works fine but I also need to apply the .error class to the surrounding div.control-group for each error. My initializer currently gives the following output: <div class="control-group"> <label class="control-label" for="post_message">Message</label> <div class="controls"> <input id="post_message" name="post[message]" required="required" size="30" type="text" value="" /><span class="help-inline">&nbsp;can't be blank</span> </div> </div> but I need something adding to my initializer so that it adds the .error class to the div.control-group like so: <div class="control-group error"> <label class="control-label" for="post_message">Message</label> <div class="controls"> <input id="post_message" name="post[message]" required="required" size="30" type="text" value="" /><span class="help-inline">&nbsp;can't be blank</span> </div> </div> The solution will probably need to allow for the fact that each validation error could have more than one label and input that are all within the same div.control-group (eg radio buttons / checkboxes / 2 text fields side by side). I assume it needs some sort of e.at_xpath() to find the div.control-group parent and add the .error class to it but I'm not sure how to do this. Can anyone help? PS This may all be possible using the formtastic or simple_form gems but I'd rather just use my own html if possible. EDIT If I put e['class'] = 'foo' in the if e.node_name.eql? 'label' section then it applies the class to the label so I think I just need to find the parent tag of e and then apply an .error class to it but I can't figure out what the xpath would be to get from label to its div.control-group parent; no combination of dots, slashes or whatever seems to work but xpath isn't my strong point.

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• Using ImageMagick to create an image from a PDF...efficiently

  - by bigsweater

  I'm using ImageMagick to create a tiny JPG thumbnail image of an already-uploaded PDF. The code works fine. It's a WordPress widget, though this isn't necessarily WordPress specific. I'm unfamiliar with ImageMagick, so I was hoping somebody could tell me if this looks terrible or isn't following some best practices of some sort, or if I'm risking crashing the server. My questions, specifically, are: Is that image cached, or does the server have to re-generate the image every time somebody views the page? If it isn't cached, what's the best way to make sure the server doesn't have to regenerate the thumbnail? I tried to create a separate folder (/thumbs) for ImageMagick to put all the images in, instead of cluttering up the WP upload folders with images of PDFs. It kept throwing a permission error, despite 777 permissions on the folder in my testing environment. Why? Do the source/destination directories have to be the same? Am I doing anything incorrectly/inefficiently here that needs to be improved? The whole widget is on Pastebin: http://pastebin.com/WnSTEDm7 Relevant code: <?php if ( $url ) { $pdf = $url; $info = pathinfo($pdf); $filename = basename($pdf,'.'.$info['extension']); $uploads = wp_upload_dir(); $file_path = str_replace( $uploads['baseurl'], $uploads['basedir'], $url ); $dest_path = str_replace( '.pdf', '.jpg', $file_path ); $dest_url = str_replace( '.pdf', '.jpg', $pdf ); exec("convert \"{$file_path}[0]\" -colorspace RGB -geometry 60 $dest_path"); ?> <div class="entry"> <div class="widgetImg"> <p><a href="<?php echo $url; ?>" title="<?php echo $filename; ?>"><?php echo "<img src='".$dest_url."' alt='".$filename."' class='blueBorder' />"; ?></a></p> </div> <div class="widgetText"> <?php echo wpautop( $desc ); ?> <p><a class="downloadLink" href="<?php echo $url; ?>" title="<?php echo $filename; ?>">Download</a></p> </div> </div> <?php } ?> As you can see, the widget grabs whatever PDF is attached to the current page being viewed, creates an image of the first page of the PDF, stores it, then links to it in HTML. Thanks for any and all help!

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• HTML-like GUI Framework in Java

  - by wintermute

  I was recently brought onto a project where we are developing a lot GUI elements for BlackBerry devices. The standard RIM APIs are pretty basic, almost never do what is required and are difficult or impossible to extend, so we end up re-implementing chunks of it. Currently the code we have isn't super organized and factored so there are lots of little tricks that get implemented over and over again. I had a thought about how to aid development efforts on this platform and wanted to see if the community could tell me if I'm still sane or if I've gone totally nuts. By far, the biggest organizational problem I've run into is making sure that each screen is laid out properly with proper padding and such. The current approach is to manually keep track of padding like so: protected void sublayout(int width, int height) { final int padding = 5; int y = padding; int x = padding; layoutChild(_someChild, width - padding * 2, height / 3 - padding * 2); setPositionChild(_someChild, x, y); y += _someChild.getHeight() + padding; // Calculate where to start drawing next. /* ... snipped ... */ } As you can see, positioning elements on a screen is a nightmare due to the tedium. I have investigated other GUI frameworks but, for a variety of reasons, it is difficult to find one that suites our purposes. One potential solution that came to me is to create a GUI framework who's API resembles HTML/CSS. This would allow for things like padding, margins, borders and colours to be handled through a sort of CSS API while the content would be organized using the HTML part of the API. It might look something like this: public class OptionsScreen extends Document { public OptionsScreen() { // You would set the style (like CSS style) through the constructor. Div content = new Div(new Style(new Padding(5), Color.BLACK)); // Then build up a tree of elements which can each have their own style's. // Each element knows how to draw itself, but it doesn't have to worry about // manually handling things like padding. // content.addChild(new P("This is a paragraph", new Style(new Padding(), Color.RED))); Ul list = new Ul(); list.addChild(new Li("item 1")); list.addChild(new Li("item 2")); content.addChild(list); addChild(content); } } I can imagine this making it easier to customize the UI of our app (which is very important) with different fonts, colours and layouts. Does this idea belong on The Daily WTF or do you think there is some promise?

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• get renamed file names of multiple upload form [js array] in codeigniter

  - by artmania

  Hi friends, I use codeigniter. I have a multiple image upload form. The code below is working well for uploading, but I also need to save file names to database. How can I get the names in here? I spent hours & hours :/ but could not sort it :/ Appreciate helps!!! uploadform.php echo form_open_multipart('gallery/upload'); <input type="file" name="photo" size="50" /> <input type="file" name="thumb" size="50" /> <input type="submit" value="Upload" /> </form> I have a controller between form view and model load model (of course : )) but didnt post here because of no need. gallery_model.php function multiple_upload($upload_dir = 'uploads/', $config = array()) { /* Upload */ $CI =& get_instance(); $files = array(); if(empty($config)) { $config['upload_path'] = realpath($upload_dir); $config['allowed_types'] = 'gif|jpg|jpeg|jpe|png'; $config['max_size'] = '2048'; } $CI->load->library('upload', $config); $errors = FALSE; foreach($_FILES as $key => $value) { if( ! empty($value['name'])) { if( ! $CI->upload->do_upload($key)) { $data['upload_message'] = $CI->upload->display_errors(ERR_OPEN, ERR_CLOSE); // ERR_OPEN and ERR_CLOSE are error delimiters defined in a config file $CI->load->vars($data); $errors = TRUE; } else { // Build a file array from all uploaded files $files[] = $CI->upload->data(); } } } // There was errors, we have to delete the uploaded files if($errors) { foreach($files as $key => $file) { @unlink($file['full_path']); } } elseif(empty($files) AND empty($data['upload_message'])) { $CI->lang->load('upload'); $data['upload_message'] = ERR_OPEN.$CI->lang->line('upload_no_file_selected').ERR_CLOSE; $CI->load->vars($data); } else { return $files; } /* ------------------------------- Insert to database */ // problem is here, i need file names to add db. // if there is already same names file at the folder, it rename file itself. so in such case, I need renamed file name :/ } }

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• Schema to support dynamic properties

  - by Johan Fredrik Varen

  Hi people. I'm working on an editor that enables its users to create "object" definitions in real-time. A definition can contain zero or more properties. A property has a name a type. Once a definition is created, a user can create an object of that definition and set the property values of that object. So by the click of a mouse-button, the user should ie. be able to create a new definition called "Bicycle", and add the property "Size" of type "Numeric". Then another property called "Name" of type "Text", and then another property called "Price" of type "Numeric". Once that is done, the user should be able to create a couple of "Bicycle" objects and fill in the "Name" and "Price" property values of each bike. Now, I've seen this feature in several software products, so it must be a well-known concept. My problem started when I sat down and tried to come up with a DB schema to support this data structure, because I want the property values to be stored using the appropriate column types. Ie. a numeric property value is stored as, say, an INT in the database, and a textual property value is stored as VARCHAR. First, I need a table that will hold all my object definitions: Table obj_defs id | name | ---------------- 1 | "Bicycle" | 2 | "Book" | Then I need a table for holding what sort of properties each object definition should have: Table prop_defs id | obj_def_id | name | type | ------------------------------------ 1 | 1 | "Size" | ? | 2 | 1 | "Name" | ? | 3 | 1 | "Price" | ? | 4 | 2 | "Title" | ? | 5 | 2 | "Author" | ? | 6 | 2 | "ISBN" | ? | I would also need a table that holds each object: Table objects id | created | updated | ------------------------------ 1 | 2011-05-14 | 2011-06-15 | 2 | 2011-05-14 | 2011-06-15 | 3 | 2011-05-14 | 2011-06-15 | Finally, I need a table that will hold the actual property values of each object, and one solution is for this table to have one column for each possible value type, such as this: Table prop_vals id | prop_def_id | object_id | numeric | textual | boolean | ------------------------------------------------------------ 1 | 1 | 1 | 27 | | | 2 | 2 | 1 | | "Trek" | | 3 | 3 | 1 | 1249 | | | 4 | 1 | 2 | 26 | | | 5 | 2 | 2 | | "GT" | | 6 | 3 | 2 | 159 | | | 7 | 4 | 3 | | "It" | | 8 | 5 | 3 | | "King" | | 9 | 6 | 4 | 9 | | | If I implemented this schema, what would the "type" column of the prop_defs table hold? Integers that each map to a column name, varchars that simply hold the column name? Any other possibilities? Would a stored procedure help me out here in some way? And what would the SQL for fetching the "name" property of object 2 look like?

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• NSNotifications vs delegate for multiple instances of same protocol

  - by Brent Traut

  I could use some architectural advice. I've run into the following problem a few times now and I've never found a truly elegant way to solve it. The issue, described at the highest level possible:I have a parent class that would like to act as the delegate for multiple children (all using the same protocol), but when the children call methods on the parent, the parent no longer knows which child is making the call. I would like to use loose coupling (delegates/protocols or notifications) rather than direct calls. I don't need multiple handlers, so notifications seem like they might be overkill. To illustrate the problem, let me try a super-simplified example: I start with a parent view controller (and corresponding view). I create three child views and insert each of them into the parent view. I would like the parent view controller to be notified whenever the user touches one of the children. There are a few options to notify the parent: Define a protocol. The parent implements the protocol and sets itself as the delegate to each of the children. When the user touches a child view, its view controller calls its delegate (the parent). In this case, the parent is notified that a view is touched, but it doesn't know which one. Not good enough. Same as #1, but define the methods in the protocol to also pass some sort of identifier. When the child tells its delegate that it was touched, it also passes a pointer to itself. This way, the parent know exactly which view was touched. It just seems really strange for an object to pass a reference to itself. Use NSNotifications. The parent defines a separate method for each of the three children and then subscribes to the "viewWasTouched" notification for each of the three children as the notification sender. The children don't need to attach themselves to the user dictionary, but they do need to send the notification with a pointer to themselves as the scope. Same as #4, but rather than using separate methods, the parent could just use one with a switch case or other branching along with the notification's sender to determine which path to take. Create multiple man-in-the-middle classes that act as the delegates to the child views and then call methods on the parent either with a pointer to the child or with some other differentiating factor. This approach doesn't seem scalable. Are any of these approaches considered best practice? I can't say for sure, but it feels like I'm missing something more obvious/elegant.

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