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  • C++: defining maximum/minimum limits for a class

    - by Luis
    Basically what the title says... I have created a class that models time slots in a variable-granularity daily schedule (where for example the first time slot is 30 minutes, but the second time slot can be 40 minutes); the first available slot starts at (a value comparable to) 1. What I want to do now is to define somehow the maximum and minimum allowable values that this class takes and I have two practical questions in order to do so: 1.- does it make sense to define absolute minimum and maximum in such a way for a custom class? Or better, does it suffice that a value always compares as lower-than any other possible value of the type, given the class's defined relational operators, to be defined the min? (and analogusly for the max) 2.- assuming the previous question has an answer modeled after "yes" (or "yes but ..."), how do I define such max/min? I know that there is std::numeric_limits<> but from what I read it is intended for "numeric types". Do I interpret that as meaning "represented as a number" or can I make a broader assumption like "represented with numbers" or "having a correspondence to integers"? After all, it would make sense to define the minimum and maximum for a date class, and maybe for a dictionary class, but numeric_limits may not be intended for those uses (I don't have much experience with it). Plus, numeric_limits has a lot of extra members and information that I don't know what to make with. If I don't use numeric_limits, what other well-known / widely-used mechanism does C++ offer to indicate the available range of values for a class?

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  • C++. How to define template parameter of type T for class A when class T needs a type A template parameter?

    - by jaybny
    Executor class has template of type P and it takes a P object in constructor. Algo class has a template E and also has a static variable of type E. Processor class has template T and a collection of Ts. Question how can I define Executor< Processor<Algo> > and Algo<Executor> ? Is this possible? I see no way to defining this, its kind of an "infinite recursive template argument" See code. template <class T> class Processor { map<string,T> ts; void Process(string str, int i) { ts[str].Do(i); } } template <class P> class Executor { Proc &p; Executor(P &p) : Proc(p) {} void Foo(string str, int i) { p.Process(str,i); } Execute(string str) { } } template <class E> class Algo { static E e; void Do(int i) {} void Foo() { e.Execute("xxx"); } } main () { typedef Processor<Algo> PALGO; // invalid typedef Executor<PALGO> EPALGO; typedef Algo<EPALGO> AEPALGO; Executor<PALGO> executor(PALGO()); AEPALGO::E = executor; }

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  • different thread accessing MemoryStream

    - by Wayne
    There's a bit of code which writes data to a MemoryStream object directly into it's data buffer by calling GetBuffer(). It also uses and updates the Position and SetLength() properties appropriately. This code works purposes 99.9999% of the time. Literally. Only every so many 100,000's of iterations it will barf. The specific problem is that the memory.Position property suddenly returns zero instead of the appropriate value. However, code was added that checks for the 0 and throws an exception which include log of the MemoryStream properties like Position and Length in a separate method. Those return the correct value. Further addition shows that when this rare condition occurs, the memory.Position only has zero inside this particular method. Okay. Obviously, this must be a threading issue. But this code is well locked. However, the nature of this software is that it's organized by "tasks" with a scheduler and so any one of several actual O/S thread may run this code at any give time--but never more than one at a time. So it's my guess that ordinarily it so happens that the same thread keeps getting used for this method and then on a rare occasion a different thread get used. Then due to compiler optimizations, the different thread never gets the correct value. It gets a "stale" value. Ordinarily in a situation like this I would apply a "volatile" keyword to the variable in question. But that (those) variables are inside the MemoryStream object. Does anyone have any other idea? Or does this mean we have to implement our own MemoryStream object? (Just like we end up having to do with practically every collection in .NET?) It's a shame to have such an awesome platform as .NET and have virtually the entire system useless as-is for seriously parallelized applications. If I'm wrong or you have other ideas, please advise. Sincerely, Wayne

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  • Why does GLSL's arithmetic functions yield so different results on the iPad than on the simulator?

    - by cheeesus
    I'm currently chasing some bugs in my OpenGL ES 2.0 fragment shader code which is running on iOS devices. The code runs fine in the simulator, but on the iPad it has huge problems and some of the calculations yield vastly different results, I had for example 0.0 on the iPad and 4013.17 on the simulator, so I'm not talking about small differences which could be the result of some rounding errors. One of the things I noticed is that, on the iPad, float1 = pow(float2, 2.0); can yield results which are very different from the results of float1 = float2 * float2; Specifically, when using pow(x, 2.0) on a variable containing a larger negative number like -8, it seemed to return a value which satified the condition if (powResult <= 0.0). Also, the result of both operations (pow(x, 2.0) as well as x*x) yields different results in the simulator than on the iPad. Used floats are mediump, but I get the same stuff with highp. Is there a simple explanation for those differences? I'm narrowing the problem down, but it takes so much time, so maybe someone can help me here with a simple explanation.

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  • reading a file of unknown length with a function

    - by Faken
    I'm trying to write a short function that will let me quickly read in a file of unknown size and return pointer to the array of data and the length of that array but it seems my code isn't working. What am i doing wrong? int readIn(int* pointer, param parameters, string description) { string fileName = parameters.fileName + " " + description + ".bin"; ifstream readFile; readFile.open(fileName.c_str(), ios::in|ios::binary|ios::ate); int size = readFile.tellg(); int length = size / 4; int* output = new int [length]; readFile.seekg (0, ios::beg); readFile.read(reinterpret_cast<char*>(output), (size)); readFile.close(); pointer = output; // link new array with the pointer return length; } and in the main function: int* testList; int numEntries = readIn(testList, parameters, "test"); I end up with an error saying that my testList variable was used and not initialized. What am i doing wrong?

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  • How to get OCI lib to work on red hat machine to work with R Oracle?

    - by Matt Bannert
    I need to get OCI lib working on my rhel 6.3 machine and I am experiencing some trouble with OCI headers files that can't be found. I have installed (using yum install) oracle-instantclient11.2-basic-11.2.0.3.0-1.x86_64.rpm because this official page it's all I need to run OCI. To test the whole thing in general I've installed sqplus64, which worked after I set export LD_LIBRARY_PATH=/usr/lib/oracle/11.2/client64/lib. Unfortunately the headers files couldn't be found after setting LD_LIBRARY_PATH. Actually I am not surprised because there is no include directory in any of these oracle paths. So the question is: Where do I get these missing header files from? Are they actually already there and I just can find them? Btw: I am doing this whole exercise because I want to use ROracle on my R Studio server and this R package depends on the OCI library. Once I am back in R territory the road gets much less bumpier for me. EDIT: this documentation helped me a little further. However, I guess I found some header files now in: "/usr/include/oracle/11.2/client64". But which variable do I have to set to this location?

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  • Can I use drawRect to refresh a UIView subclass?

    - by Timbo
    I've created a subclass of UIView called Status which is designed to display a rectangle of a certain size (within a view) depending on the value of a variable. // Interface #import <Foundation/Foundation.h> #import <QuartzCore/QuartzCore.h> @interface Status: UIView { NSString* name; int someVariable; } @property int someVariable; @property (assign) NSString *name; - (void) createStatus: (NSString*)withName; - (void) drawRect:(CGRect)rect; @end // Implementation #import "Status.h" @implementation Status @synthesize name, someVariable; - (void) createStatus: (NSString*)withName { name = withName; someVariable = 10000; } - (void) drawRect:(CGRect)rect { CGContextRef context = UIGraphicsGetCurrentContext(); //Draw Status CGContextSetRGBFillColor(context, 0.0, 0.0, 1.0, 1); // fill CGContextFillRect(context, CGRectMake(0.0, 0.0, someVariable, 40.0)); } //// myviewcontroller implementation - (void) viewDidAppear:(BOOL)animated { [super viewDidAppear:animated]; myStatus = [[Status alloc] initWithFrame:CGRectMake(8,8,200,56)]; myStatus.backgroundColor = [UIColor grayColor]; [self.view addSubview:myStatus]; } How do I set this up so I can repeatedly call a refresh of the status bar? I'll probably call the refresh 4 times per second using a NSTimer, I'm just not sure what to call or if I should move this rectangle drawing to a separate function or something... Thanks in advance for your help :)

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  • Does F# documentation have a way to search for functions by their types?

    - by Nathan Sanders
    Say I want to know if F# has a library function of type ('T -> bool) -> 'T list -> int ie, something that counts how many items of a list that a function returns true for. (or returns the index of the first item that returns true) I used to use the big list at the MSR site for F# before the documentation on MSDN was ready. I could just search the page for the above text because the types were listed. But now the MSDN documentation only lists types on the individual pages--the module page is a mush of descriptive text. Google kinda-sorta works, but it can't help with // compatible interfaces ('T -> bool) -> Seq<'T> -> int // argument-swaps Seq<'T> -> ('T -> bool) -> int // type-variable names ('a -> bool) -> Seq<'a> -> int // wrappers ('a -> bool) -> 'a list -> option<int> // uncurried versions ('T -> bool) * 'T list -> int // .NET generic syntax ('T -> bool) -> List<'T> -> int // methods List<'T> member : ('T -> bool) -> int Haskell has a standalone program for this called Hoogle. Does F# have an equivalent, like Fing or something?

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  • Why does this Haskell code produce the "infinite type" error?

    - by Charlie Flowers
    I am new to Haskell and facing a "cannot construct infinite type" error that I cannot make sense of. In fact, beyond that, I have not been able to find a good explanation of what this error even means, so if you could go beyond my basic question and explain the "infinite type" error, I'd really appreciate it. Here's the code: intersperse :: a -> [[a]] -> [a] -- intersperse '*' ["foo","bar","baz","quux"] -- should produce the following: -- "foo*bar*baz*quux" -- intersperse -99 [ [1,2,3],[4,5,6],[7,8,9]] -- should produce the following: -- [1,2,3,-99,4,5,6,-99,7,8,9] intersperse _ [] = [] intersperse _ [x] = x intersperse s (x:y:xs) = x:s:y:intersperse s xs And here's the error trying to load it into the interpreter: Prelude :load ./chapter.3.ending.real.world.haskell.exercises.hs [1 of 1] Compiling Main ( chapter.3.ending.real.world.haskell.exercises.hs, interpreted ) chapter.3.ending.real.world.haskell.exercises.hs:147:0: Occurs check: cannot construct the infinite type: a = [a] When generalising the type(s) for `intersperse' Failed, modules loaded: none. Thanks. EDIT: Thanks to the responses, I have corrected the code and I also have a general guideline for dealing with the "infinite type" error in Haskell: Corrected code intersperse _ [] = [] intersperse _ [x] = x intersperse s (x:xs) = x ++ s:intersperse s xs What the problem was: My type signature states that the second parameter to intersperse is a list of lists. Therefore, when I pattern matched against "s (x:y:xs)", x and y became lists. And yet I was treating x and y as elements, not lists. Guideline for dealing with the "infinite type" error: Most of the time, when you get this error, you have forgotten the types of the various variables you're dealing with, and you have attempted to use a variable as if it were some other type than what it is. Look carefully at what type everything is versus how you're using it, and this will usually uncover the problem.

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  • Looking for the log file on iPhone

    - by zp26
    Hi, I have a problem. I have the code below for save a data on file. I build my app on the device, and run. The result variable is TRUE, but i don't find the file on the my iPhone device. Can you help me? Thank and sorry for my english XP -(void)saveXML:(NSString*)name:(float)x:(float)y:(float)z{ NSMutableData *data = [NSMutableData data]; NSKeyedArchiver *archiver = [[NSKeyedArchiver alloc] initForWritingWithMutableData:data]; [archiver setOutputFormat:NSPropertyListXMLFormat_v1_0]; [archiver encodeFloat:x forKey:@"x"]; [archiver encodeFloat:y forKey:@"y"]; [archiver encodeFloat:z forKey:@"z"]; [archiver encodeObject:name forKey:@"name"]; [archiver finishEncoding]; NSString* filePath = [[NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES) objectAtIndex:0] stringByAppendingPathComponent:@"XML Position"]; BOOL result = [data writeToFile:filePath atomically:YES]; if(result) [self updateTextView:@"success"]; [archiver release]; }

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  • C/C++ macro/template blackmagic to generate unique name.

    - by anon
    Macros are fine. Templates are fine. Pretty much whatever it works is fine. The example is OpenGL; but the technique is C++ specific and relies on no knowledge of OpenGL. Precise problem: I want an expression E; where I do not have to specify a unique name; such that a constructor is called where E is defined, and a destructor is called where the block E is in ends. For example, consider: class GlTranslate { GLTranslate(float x, float y, float z); { glPushMatrix(); glTranslatef(x, y, z); } ~GlTranslate() { glPopMatrix(); } }; Manual solution: { GlTranslate foo(1.0, 0.0, 0.0); // I had ti give it a name ..... } // auto popmatrix Now, I have this not only for glTranslate, but lots of other PushAttrib/PopAttrib calls too. I would prefer not to have to come up with a unique name for each var. Is there some trick involving macros templates ... or something else that will automatically create a variable who's constructor is called at point of definition; and destructor called at end of block? Thanks!

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  • How to reference var from frame on timeline in an object class

    - by brybam
    I'm using Flash Professional cs5/AS3 I'll try and describe this the best I can. I'm new to ActionScript. So, in my timeline I have a var on a frame that represents "lives" and i have some code in the timeline that takes down the number of lives depending on certain events, which all works great. so, now i wanted to make a constructor class that I could reuse for a bunch of movie clip objects and I only want these objects to be able to move if the lives variable is greater than certain number. So now, building my constructor class for these objects i just wanted put an if statement that is looking to see if the lives are greater than a certain number, which if it is then should make these objects do what i want...But, when i run the project I get "1120: Access of undefined property lives." lives is the var I made obviously like I said, and it works fine being referenced everyone else except when I make a new .as file for these objects then try and reference it. I get the same error when I try and establish "lives" in the main project class too. I'm not sure where I should put this var or how I can make it so i can reference it from an object class. I'm not really sure how to word or describe my issue which has made it hard to search for a tutorial. Any suggestions i'm sure this has to be a simple task.

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  • When should we use private variables and when should we use properties.

    - by Shantanu Gupta
    In most of the cases we usually creates a private variable and its corresponding public properties and uses them for performing our functionalities. Everyone has different approach like some ppl uses properties every where and some uses private variables within a same class as they are private and opens it to be used by external environment by using properties. Suppose I takes a scenario say insertion in a database. I creates some parameters that need to be initialized. I creates 10 private variables and their corresp public properties which are given as private string name; public string Name { get{return name;} set{name=value;} } and so on. In these cases what should be used internally variables or properties. And in those cases like public string Name { get{return name;} set{name=value>5?5:0;} //or any action can be done. this is just an eg. } In such cases what should be done.

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  • In SQL can I return a tables with a varying number of columns

    - by Matt
    I have a somewhat more complicated scenario, but I think it should be possible. I have a large SPROC whose result is a set of characteristics for a set of persons. So the Table would look something like this: Property | Client1 Client 2 Client3 ----------------------------------------------------------- Sex | M F M Age | 67 56 67 Income | Low Mid Low It's built using cursors, iterating over different datasets. The problem I am facing is that there is a varying number of Clients and Properties, so an equally valid result over different input sets might be: Property | Client1 Client 2 ------------------------------------------- Sex | M F Age | 67 56 Weight | 122 122 The different number of properties is easy, those are just extra rows. My problem is that I need to declare a temporary table with a varying number of columns. There could be 2 clients or 100. Every client in guaranteed to have every property ultimately listed. What SQL structure would statisfy this and how can I declare it and insert things into it? I can't just flip the columns and rows either because there is a variable number of each.

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  • Creating a dynamic two-column iOS spinning wheel with HTML/Javascript

    - by JSW189
    I am trying to create a dynamic two-column spinning wheel for iOS Safari using this HTML/Javascript wheel. However, I am having trouble getting the value of the first column to change the results of the second column. I have tried using an if statement to get the value of the first variable (var beverage) and add the value of the second column correspondingly. Does anybody know what I am doing wrong/if there is a better approach? function openBirthDate() { var beverage = { 1:'Coffee', 2:'Soda' }; //THIS IS WHERE I'M HAVING TROUBLE var results = SpinningWheel.getSelectedValues(); if (results.values === 1) { var company = { 1:'Starbucks', 2:'Dunkin Donuts' }; } else { var company = { 1:'Coke', 2:'Pepsi' }; } var size = { 1:'Tall', 2:'Grande', 3:'Venti' }; SpinningWheel.addSlot(type, '', 1); SpinningWheel.addSlot(company, '', 1); SpinningWheel.addSlot(size, '', 1); SpinningWheel.setCancelAction(cancel); SpinningWheel.setDoneAction(done); SpinningWheel.open(); } function done() { var results = SpinningWheel.getSelectedValues(); document.getElementById('result').innerHTML = 'values: ' + results.values.join(' ') + '<br />keys: ' + results.keys.join(', '); } function cancel() { document.getElementById('result').innerHTML = 'cancelled!'; } window.addEventListener('load', function(){ setTimeout(function(){ window.scrollTo(0,0); }, 100); }, true);

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  • Unpacking varargin to individual variables

    - by Richie Cotton
    I'm writing a wrapper to a function that takes varargin as its inputs. I want to preserve the function signature in the wrapper, but nesting varargin causes all the variable to be lumped together. function inner(varargin) %#ok<VANUS> % An existing function disp(nargin) end function outer(varargin) % My wrapper inner(varargin); end outer('foo', 1:3, {}) % Uh-oh, this is 1 I need a way to unpack varargin in the outer function, so that I have a list of individual variables. There is a really nasty way to do this by constructing a string of the names of the variables to pass the inner, and calling eval. function outer2(varargin) %#ok<VANUS> % My wrapper, second attempt inputstr = ''; for i = 1:nargin inputstr = [inputstr 'varargin{' num2str(i) '}']; %#ok<AGROW> if i < nargin inputstr = [inputstr ', ']; %#ok<AGROW> end end eval(['inner(' inputstr ')']); end outer2('foo', 1:3, {}) % 3, as it should be Can anyone think of a less hideous way of doing things, please?

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  • java.awt.Robot.keyPress for continuous keystrokes

    - by Deb
    So, here's my problem. I have a java program which will send keystroke messages to a game (built in Unity), based on how the user interacts with an android phone. (My java program is a listener for the android interaction over wi-fi) Now, in order to do this, I am using java.awt.Robot to send keyPresses to the game window. I have the following code block written in my listener program: if(interacting) { Robot robot = new Robot(); robot.keyPress(VK_A); robot.delay(20); //to simulate the normal keyboard rate } Now the variable interacting will be true as long as the user presses down on the touch screen of the phone, and what I intend to achieve is a continuous chain of keystroke messages being delivered to the game (through the listener). However, this is severely affecting performance, for some reason. I am noticing that the game becomes slow (rapidly dropping frame rates), and even the computer becomes slow, in general. What's going wrong? Should I use a robot.keyRelease(VK_A) after each keyPress? But my game has a different action mapped to the release of a key, and I do not want rapid key presses and releases; what I really want is to simulate continuous keystrokes, in exactly the way it would behave if the user were pressing down the A key on their keyboard manually. Please help.

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  • using 'or' operator not working for menu

    - by John Wilkes
    In my code here, I have a CSS class called "active" which I use if the $_GET['page'] == tutorials, php, mysql, etc... The problem is, even if the 'page' variable is not equal to any of these values, the Tutorials button in this case is still active for some reason. Any ideas why this would be happening? Am I using the 'or' (||) operand incorrectly? <?php if($_GET['page'] == 'tutorials' || 'php' || 'mysql' || 'html' || 'css' || 'js') { ?> <li class="active"> <?php } else { ?> <li> <?php } ?> <a href="index.php?page=tutorials">Tutorials</a> <ul> <li><a href="index.php?page=php">PHP</a></li> <li><a href="index.php?page=mysql">MySQL</a></li> <li><a href="index.php?page=html">HTML</a></li> <li><a href="index.php?page=css">CSS</a></li> <li><a href="index.php?page=js">JS</a></li> </ul> </li>

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  • Open an Emacs buffer when a command tries to open an editor in shell-mode

    - by Chris Conway
    I like to use Emacs' shell mode, but it has a few deficiencies. One of those is that it's not smart enough to open a new buffer when a shell command tries to invoke an editor. For example with the environment variable VISUAL set to vim I get the following from svn propedit: $ svn propedit svn:externals . "svn-prop.tmp" 2L, 149C[1;1H ~ [4;1H~ [5;1H~ [6;1H~ [7;1H~ ... (It may be hard to tell from the representation, but it's a horrible, ugly mess.) With VISUAL set to "emacs -nw", I get $ svn propedit svn:externals . emacs: Terminal type "dumb" is not powerful enough to run Emacs. It lacks the ability to position the cursor. If that is not the actual type of terminal you have, use the Bourne shell command `TERM=... export TERM' (C-shell: `setenv TERM ...') to specify the correct type. It may be necessary to do `unset TERMINFO' (C-shell: `unsetenv TERMINFO') as well.svn: system('emacs -nw svn-prop.tmp') returned 256 (It works with VISUAL set to just emacs, but only from inside an Emacs X window, not inside a terminal session.) Is there a way to get shell mode to do the right thing here and open up a new buffer on behalf of the command line process?

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  • How does scope in Javascript work?

    - by Jim
    I can not understand how scoping works in Javascript. E.g. <html> <head> <script>var userName = "George"; </script> </head> <body> ...... <script> document.write('Name = ' + userName); </script> </body> </html> The variable userName is declared in another "section" of a script. As I understand it the browser renders html and executes code in the order it finds it. So how does userName in the second script tag gets resolved? Does it go to a global setting? Anything I declare earlier is global? I noticed the same happens if I do something like: <html> <head> <script> do { var userName = "George"; //bla } while (someCondition); </script> </head> <body> ...... <script> document.write('Name = ' + userName); </script> </body> </html> Even when userName is declared inside {} it is still resolved in the second script. How is that possible?

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  • jQuery $.ajax calls success handler when reuqest fails because of browser reloading

    - by Martin
    I have the following code: $.ajax({ type: "POST", url: url, data: sendable, dataType: "json", success: function(data) { if(customprocessfunc) customprocessfunc(data); }, error: function(XMLHttpRequest, textStatus, errorThrown){ // error handler here } }); I have a timer which makes AJAX requests often. If I do not receive anything in 'data', I show an error message to the user - it means, something wnet bad on the server. The problem is when user reloads the page while the AJAX call is in progress. I can see in the firebug that the AJAX call fails (URL is colored red and no HTTP status is displayed) so I expect that jQuery will stop the reuqest or at least go to the error handler. But it goes to the success handler and passes null in the 'data' variable. As a result, when user reloads the page, sometimes he can see my big red message about unknown error (because data is null). Is there any way to make jQuery abort the request on complete reloading all at least not to call my success function? I have no way to know in the success handler why the data is null - did it came empty from the server or the call was aborted because of reload.

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  • Oracle 10.1 and 11.2 produce different XML using the same statement

    - by MindFyer
    I am migrating a database from Oracle 10.1 to 11.2 and I have the following problem. The statement SELECT '<?xml version="1.0" encoding="utf-8" ?>' || (Xml).getClobVal() AS XmlClob FROM ( SELECT XmlElement( "Element1", ( SELECT XmlAgg(tpx.Xml) FROM ( SELECT XmlElement("Element3",XmlForest('content' as Element4)) AS Xml FROM dual ) tpx ) AS "Element2" ) AS Xml FROM dual ) On the original 10.1 database produces XML like this... <?xml version="1.0" encoding="utf-8"?> <Element1> <Element2> <Element3> <ELEMENT4>content</ELEMENT4> </Element3> </Element2> </Element1> On the new 11.2 system it looks like this... <?xml version="1.0" encoding="utf-8"?> <Element1> <Element3> <ELEMENT4>content</ELEMENT4> </Element3> </Element1> Is there some environmental variable I am missing that tells Oracle how to format its XML. There are hundreds of thousands of lines of PL/SQL in the database; it would be a mammoth task to rewrite if it turned out they had changed they way Oracle formats XML between versions. Hopefully someone has come accross this before. Thanks

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  • Java: Tracking a user login session - Session EJBs vs HTTPSession

    - by bguiz
    If I want to keep track of a conversational state with each client using my web application, which is the better alternative - a Session Bean or a HTTP Session - to use? Using HTTP Session: //request is a variable of the class javax.servlet.http.HttpServletRequest //UserState is a POJO HttpSession session = request.getSession(true); UserState state = (UserState)(session.getAttribute("UserState")); if (state == null) { //create default value .. } String uid = state.getUID(); //now do things with the user id Using Session EJB: In the implementation of ServletContextListener registered as a Web Application Listener in WEB-INF/web.xml: //UserState NOT a POJO this this time, it is //the interface of the UserStateBean Stateful Session EJB @EJB private UserState userStateBean; public void contextInitialized(ServletContextEvent sce) { ServletContext servletContext = sce.getServletContext(); servletContext.setAttribute("UserState", userStateBean); ... In a JSP: public void jspInit() { UserState state = (UserState)(getServletContext().getAttribute("UserState")); ... } Elsewhere in the body of the same JSP: String uid = state.getUID(); //now do things with the user id It seems to me that the they are almost the same, with the main difference being that the UserState instance is being transported in the HttpRequest.HttpSession in the former, and in a ServletContext in the case of the latter. Which of the two methods is more robust, and why?

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  • Pass in a value into Python Class through command line

    - by chrissygormley
    Hello, I have got some code to pass in a variable into a script from the command line. The script is: import sys, os def function(var): print var class function_call(object): def __init__(self, sysArgs): try: self.function = None self.args = [] self.modulePath = sysArgs[0] self.moduleDir, tail = os.path.split(self.modulePath) self.moduleName, ext = os.path.splitext(tail) __import__(self.moduleName) self.module = sys.modules[self.moduleName] if len(sysArgs) > 1: self.functionName = sysArgs[1] self.function = self.module.__dict__[self.functionName] self.args = sysArgs[2:] except Exception, e: sys.stderr.write("%s %s\n" % ("PythonCall#__init__", e)) def execute(self): try: if self.function: self.function(*self.args) except Exception, e: sys.stderr.write("%s %s\n" % ("PythonCall#execute", e)) if __name__=="__main__": test = test() function_call(sys.argv).execute() This works by entering ./function <function> <arg1 arg2 ....>. The problem is that I want to to select the function I want that is in a class rather than just a function by itself. The code I have tried is the same except that function(var): is in a class. I was hoping for some ideas on how to modify my function_call class to accept this. Thanks for any help.

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  • Silverlight Binding - Binds when item is added but doesn't get updates.

    - by dw
    Hello, I'm sorta at a loss to why this doesn't work considering I got it from working code, just added a new level of code, but here's what I have. Basically, when I bind the ViewModel to a list, the binding picks up when Items are added to a collection. However, if an update occurs to the item that is bound, it doesn't get updated. Basically, I have an ObservableCollection that contains a custom class with a string value. When that string value gets updated I need it to update the List. Right now, when I debug, the list item does get updated correctly, but the UI doesn't reflect the change. If I set the bound item to a member variable and null it out then reset it to the right collection it will work, but not desired behavior. Here is a mockup of the code, hopefully someone can tell me where I am wrong. Also, I've tried implementing INofityPropertyChanged at every level in the code below. public class Class1 { public string ItemName; } public class Class2 { private Class2 _items; private Class2() //Singleton { _items = new ObservableCollection<Class1>(); } public ObservableCollection<Class1> Items { get { return _items; } internal set { _items = value; } } } public class Class3 { private Class2 _Class2Instnace; private Class3() { _Class2Instnace = Class2.Instance; } public ObservableCollection<Class1> Items2 { get {return _Class2Instnace.Items; } } } public class MyViewModel : INofityPropertyChanged { private Class3 _myClass3; private MyViewModel() { _myClass3 = new Class3(); } private BindingItems { get { return _myClass3.Items2; } // Binds when adding items but not when a Class1.ItemName gets updated. } }

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