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  • Erasing and modifying elements in Boost MultiIndex Container

    - by Sarah
    I'm trying to use a Boost MultiIndex container in my simulation. My knowledge of C++ syntax is very weak, and I'm concerned I'm not properly removing an element from the container or deleting it from memory. I also need to modify elements, and I was hoping to confirm the syntax and basic philosophy here too. // main.cpp ... #include <boost/multi_index_container.hpp> #include <boost/multi_index/hashed_index.hpp> #include <boost/multi_index/member.hpp> #include <boost/multi_index/ordered_index.hpp> #include <boost/multi_index/mem_fun.hpp> #include <boost/tokenizer.hpp> #include <boost/shared_ptr.hpp> ... #include "Host.h" // class Host, all members private, using get fxns to access using boost::multi_index_container; using namespace boost::multi_index; typedef multi_index_container< boost::shared_ptr< Host >, indexed_by< hashed_unique< const_mem_fun<Host,int,&Host::getID> > // ordered_non_unique< BOOST_MULTI_INDEX_MEM_FUN(Host,int,&Host::getAge) > > // end indexed_by > HostContainer; typedef HostContainer::nth_index<0>::type HostsByID; int main() { ... HostContainer allHosts; Host * newHostPtr; newHostPtr = new Host( t, DOB, idCtr, 0, currentEvents ); allHosts.insert( boost::shared_ptr<Host>(newHostPtr) ); // allHosts gets filled up int randomHostID = 4; int newAge = 50; modifyHost( randomHostID, allHosts, newAge ); killHost( randomHostID, allHosts ); } void killHost( int id, HostContainer & hmap ){ HostsByID::iterator it = hmap.find( id ); cout << "Found host id " << (*it)->getID() << "Attempting to kill. hmap.size() before is " << hmap.size() << " and "; hmap.erase( it ); // Is this really erasing (freeing from mem) the underlying Host object? cout << hmap.size() << " after." << endl; } void modifyHost( int id, HostContainer & hmap, int newAge ){ HostsByID::iterator it = hmap.find( id ); (*it) -> setAge( newAge ); // Not actually the "modify" function for MultiIndex... } My questions are In the MultiIndex container allHosts of shared_ptrs to Host objects, is calling allHosts.erase( it ) on an iterator to the object's shared_ptr enough to delete the object permanently and free it from memory? It appears to be removing the shared_ptr from the container. The allhosts container currently has one functioning index that relies on the host's ID. If I introduce an ordered second index that calls on a member function (Host::getAge()), where the age changes over the course of the simulation, is the index always going to be updated when I refer to it? What is the difference between using the MultiIndex's modify to modify the age of the underlying object versus the approach I show above? I'm vaguely confused about what is assumed/required to be constant in MultiIndex. Thanks in advance. Update Here's my attempt to get the modify syntax working, based on what I see in a related Boost example. struct update_age { update_age():(){} // have no idea what this really does... elicits error void operator() (boost::shared_ptr<Host> ptr) { ptr->incrementAge(); // incrementAge() is a member function of class Host } }; and then in modifyHost, I'd have hmap.modify(it,update_age). Even if by some miracle this turns out to be right, I'd love some kind of explanation of what's going on.

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  • Avoiding Agnostic Jagged Array Flattening in Powershell

    - by matejhowell
    Hello, I'm running into an interesting problem in Powershell, and haven't been able to find a solution to it. When I google (and find things like this post), nothing quite as involved as what I'm trying to do comes up, so I thought I'd post the question here. The problem has to do with multidimensional arrays with an outer array length of one. It appears Powershell is very adamant about flattening arrays like @( @('A') ) becomes @( 'A' ). Here is the first snippet (prompt is , btw): > $a = @( @( 'Test' ) ) > $a.gettype().isarray True > $a[0].gettype().isarray False So, I'd like to have $a[0].gettype().isarray be true, so that I can index the value as $a[0][0] (the real world scenario is processing dynamic arrays inside of a loop, and I'd like to get the values as $a[$i][$j], but if the inner item is not recognized as an array but as a string (in my case), you start indexing into the characters of the string, as in $a[0][0] -eq 'T'). I have a couple of long code examples, so I have posted them at the end. And, for reference, this is on Windows 7 Ultimate with PSv2 and PSCX installed. Consider code example 1: I build a simple array manually using the += operator. Intermediate array $w is flattened, and consequently is not added to the final array correctly. I have found solutions online for similar problems, which basically involve putting a comma before the inner array to force the outer array to not flatten, which does work, but again, I'm looking for a solution that can build arrays inside a loop (a jagged array of arrays, processing a CSS file), so if I add the leading comma to the single element array (implemented as intermediate array $y), I'd like to do the same for other arrays (like $z), but that adversely affects how $z is added to the final array. Now consider code example 2: This is closer to the actual problem I am having. When a multidimensional array with one element is returned from a function, it is flattened. It is correct before it leaves the function. And again, these are examples, I'm really trying to process a file without having to know if the function is going to come back with @( @( 'color', 'black') ) or with @( @( 'color', 'black'), @( 'background-color', 'white') ) Has anybody encountered this, and has anybody resolved this? I know I can instantiate framework objects, and I'm assuming everything will be fine if I create an object[], or a list<, or something else similar, but I've been dealing with this for a little bit and something sure seems like there has to be a right way to do this (without having to instantiate true framework objects). Code Example 1 function Display($x, [int]$indent, [string]$title) { if($title -ne '') { write-host "$title`: " -foregroundcolor cyan -nonewline } if(!$x.GetType().IsArray) { write-host "'$x'" -foregroundcolor cyan } else { write-host '' $s = new-object string(' ', $indent) for($i = 0; $i -lt $x.length; $i++) { write-host "$s[$i]: " -nonewline -foregroundcolor cyan Display $x[$i] $($indent+1) } } if($title -ne '') { write-host '' } } ### Start Program $final = @( @( 'a', 'b' ), @('c')) Display $final 0 'Initial Value' ### How do we do this part ??? ########### ## $w = @( @('d', 'e') ) ## $x = @( @('f', 'g'), @('h') ) ## # But now $w is flat, $w.length = 2 ## ## ## # Even if we put a leading comma (,) ## # in front of the array, $y will work ## # but $w will not. This can be a ## # problem inside a loop where you don't ## # know the length of the array, and you ## # need to put a comma in front of ## # single- and multidimensional arrays. ## $y = @( ,@('D', 'E') ) ## $z = @( ,@('F', 'G'), @('H') ) ## ## ## ########################################## $final += $w $final += $x $final += $y $final += $z Display $final 0 'Final Value' ### Desired final value: @( @('a', 'b'), @('c'), @('d', 'e'), @('f', 'g'), @('h'), @('D', 'E'), @('F', 'G'), @('H') ) ### As in the below: # # Initial Value: # [0]: # [0]: 'a' # [1]: 'b' # [1]: # [0]: 'c' # # Final Value: # [0]: # [0]: 'a' # [1]: 'b' # [1]: # [0]: 'c' # [2]: # [0]: 'd' # [1]: 'e' # [3]: # [0]: 'f' # [1]: 'g' # [4]: # [0]: 'h' # [5]: # [0]: 'D' # [1]: 'E' # [6]: # [0]: 'F' # [1]: 'G' # [7]: # [0]: 'H' Code Example 2 function Display($x, [int]$indent, [string]$title) { if($title -ne '') { write-host "$title`: " -foregroundcolor cyan -nonewline } if(!$x.GetType().IsArray) { write-host "'$x'" -foregroundcolor cyan } else { write-host '' $s = new-object string(' ', $indent) for($i = 0; $i -lt $x.length; $i++) { write-host "$s[$i]: " -nonewline -foregroundcolor cyan Display $x[$i] $($indent+1) } } if($title -ne '') { write-host '' } } function funA() { $ret = @() $temp = @(0) $temp[0] = @('p', 'q') $ret += $temp Display $ret 0 'Inside Function A' return $ret } function funB() { $ret = @( ,@('r', 's') ) Display $ret 0 'Inside Function B' return $ret } ### Start Program $z = funA Display $z 0 'Return from Function A' $z = funB Display $z 0 'Return from Function B' ### Desired final value: @( @('p', 'q') ) and same for r,s ### As in the below: # # Inside Function A: # [0]: # [0]: 'p' # [1]: 'q' # # Return from Function A: # [0]: # [0]: 'p' # [1]: 'q' Thanks, Matt

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  • PHP Form not working IE and Chrome, but fine in FF

    - by RO
    <? if(isset($_POST['accountUser']) && isset($_POST['accountPassword'])) { include("dbase.php"); include("settings.php"); if ($_POST['accountType']=="member") { $database="chatusers"; } else if ($_POST['accountType']=="model") { $database="chatmodels"; } else if ($_POST['accountType']=="studioop") { $database="chatoperators"; } $userExists=false; $result = mysql_query("SELECT id,user,password,status FROM $database WHERE status!='pending' AND status!='rejected' "); while($row = mysql_fetch_array($result)) { $tempUser=$row["user"]; $tempPass=$row["password"]; $tempId=$row["id"]; if ($_POST['accountUser']==$tempUser && md5($_POST['accountPassword'])==$tempPass) { if ($row["status"]=="blocked") { $userExists=true; $errorMsg="Account is blocked, please contact the administrator for more details"; } else { $userExists=true; $currentTime=time(); mysql_query("UPDATE $database SET lastLogIn='$currentTime' WHERE id = '$tempId' LIMIT 1"); setcookie("usertype", $database, time()+3600); setcookie("id", $tempId, time()+3600); header("Location: cp/$database/"); } } } if (!$userExists){ $errorMsg="Wrong Username or password"; } } else if (isset($_GET['from']) && $_GET['from']=="recoverpass"){ $errorMsg="Your new password has been sent to your mail"; } else { $errorMsg="Please complete username and password fields"; } ?> <? include("_main.header.php"); ?> <table width="720" height="200" border="0" align="center" cellpadding="0" cellspacing="0"> <tr> <td align="center" valign="middle"><form action="login.php" method="post" enctype="application/x-www-form-urlencoded" name="form1"> <p>&nbsp;</p> <table width="720" border="0" align="center"> <tr> <td colspan="2"><p align="left"> <span class="error"><?php if ( isset($errorMsg) && $errorMsg!=""){ echo $errorMsg; } ?></span> <br> <br> </p></td> </tr> <tr> <td width="210" align="right" valign="top" class="form_definitions"><div align="right">Username:</div></td> <td align="left" valign="top"><input name="accountUser" type="text" id="accountUser" value="<? echo $_GET[user];?>" size="24" maxlength="24"></td> </tr> <tr> <td align="right" valign="top" class="form_definitions"><div align="right">Password:</div></td> <td align="left" valign="top"><input name="accountPassword" type="password" id="accountPassword2" size="24" maxlength="24"></td> </tr> <tr> <td align="right" valign="top" class="form_definitions"><div align="right">Account type:</div></td> <td align="left" valign="top"> <select name="accountType" id="select"> <option value="member" selected>Member</option> <option value="model">Model</option> <option value="studioop">Studio Operator</option> </select> <div align="left"></div></td> </tr> <tr> <td align="right" valign="top" class="form_definitions">&nbsp;</td> <td align="left" valign="top"> <input type="submit" name="Submit" value="Log In to your account"> <div align="left"></div></td> </tr> <tr> <td align="right" valign="top" class="form_definitions">&nbsp;</td> <td align="left" valign="top"><a href="lostpassword.php" class="left">Lost Password? Press Here!</a></td> </tr> </table> </form></td> </tr> </table> <br> <br> <? include("_main.footer.php"); ?>

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  • Signals and threads - good or bad design decision?

    - by Jens
    I have to write a program that performs highly computationally intensive calculations. The program might run for several days. The calculation can be separated easily in different threads without the need of shared data. I want a GUI or a web service that informs me of the current status. My current design uses BOOST::signals2 and BOOST::thread. It compiles and so far works as expected. If a thread finished one iteration and new data is available it calls a signal which is connected to a slot in the GUI class. My question(s): Is this combination of signals and threads a wise idea? I another forum somebody advised someone else not to "go down this road". Are there potential deadly pitfalls nearby that I failed to see? Is my expectation realistic that it will be "easy" to use my GUI class to provide a web interface or a QT, a VTK or a whatever window? Is there a more clever alternative (like other boost libs) that I overlooked? following code compiles with g++ -Wall -o main -lboost_thread-mt <filename>.cpp code follows: #include <boost/signals2.hpp> #include <boost/thread.hpp> #include <boost/bind.hpp> #include <iostream> #include <iterator> #include <string> using std::cout; using std::cerr; using std::string; /** * Called when a CalcThread finished a new bunch of data. */ boost::signals2::signal<void(string)> signal_new_data; /** * The whole data will be stored here. */ class DataCollector { typedef boost::mutex::scoped_lock scoped_lock; boost::mutex mutex; public: /** * Called by CalcThreads call the to store their data. */ void push(const string &s, const string &caller_name) { scoped_lock lock(mutex); _data.push_back(s); signal_new_data(caller_name); } /** * Output everything collected so far to std::out. */ void out() { typedef std::vector<string>::const_iterator iter; for (iter i = _data.begin(); i != _data.end(); ++i) cout << " " << *i << "\n"; } private: std::vector<string> _data; }; /** * Several of those can calculate stuff. * No data sharing needed. */ struct CalcThread { CalcThread(string name, DataCollector &datcol) : _name(name), _datcol(datcol) { } /** * Expensive algorithms will be implemented here. * @param num_results how many data sets are to be calculated by this thread. */ void operator()(int num_results) { for (int i = 1; i <= num_results; ++i) { std::stringstream s; s << "["; if (i == num_results) s << "LAST "; s << "DATA " << i << " from thread " << _name << "]"; _datcol.push(s.str(), _name); } } private: string _name; DataCollector &_datcol; }; /** * Maybe some VTK or QT or both will be used someday. */ class GuiClass { public: GuiClass(DataCollector &datcol) : _datcol(datcol) { } /** * If the GUI wants to present or at least count the data collected so far. * @param caller_name is the name of the thread whose data is new. */ void slot_data_changed(string caller_name) const { cout << "GuiClass knows: new data from " << caller_name << std::endl; } private: DataCollector & _datcol; }; int main() { DataCollector datcol; GuiClass mc(datcol); signal_new_data.connect(boost::bind(&GuiClass::slot_data_changed, &mc, _1)); CalcThread r1("A", datcol), r2("B", datcol), r3("C", datcol), r4("D", datcol), r5("E", datcol); boost::thread t1(r1, 3); boost::thread t2(r2, 1); boost::thread t3(r3, 2); boost::thread t4(r4, 2); boost::thread t5(r5, 3); t1.join(); t2.join(); t3.join(); t4.join(); t5.join(); datcol.out(); cout << "\nDone" << std::endl; return 0; }

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  • C# Generic Arrays and math operations on it

    - by msedi
    Hello, I'm currently involved in a project where I have very large image volumes. This volumes have to processed very fast (adding, subtracting, thresholding, and so on). Additionally most of the volume are so large that they event don't fit into the memory of the system. For that reason I have created an abstract volume class (VoxelVolume) that host the volume and image data and overloads the operators so that it's possible to perform the regular mathematical operations on volumes. Thereby two more questions opened up which I will put into stackoverflow into two additional threads. Here is my first question. My volume is implemented in a way that it only can contain float array data, but most of the containing data is from an UInt16 image source. Only operations on the volume can create float array images. When I started implementing such a volume the class looked like following: public abstract class VoxelVolume<T> { ... } but then I realized that overloading the operators or return values would get more complicated. An example would be: public abstract class VoxelVolume<T> { ... public static VoxelVolume<T> Import<T>(param string[] files) { } } also adding two overloading operators would be more complicated: ... public static VoxelVolume<T> operator+(VoxelVolume<T> A, VoxelVolume<T> B) { ... } Let's assume I can overcome the problems described above, nevertheless I have different types of arrays that contain the image data. Since I have fixed my type in the volumes to float the is no problem and I can do an unsafe operation when adding the contents of two image volume arrays. I have read a few threads here and had a look around the web, but found no real good explanation of what to do when I want to add two arrays of different types in a fast way. Unfortunately every math operation on generics is not possible, since C# is not able to calculate the size of the underlying data type. Of course there might by a way around this problem by using C++/CLR, but currently everything I have done so far, runs in 32bit and 64bit without having to do a thing. Switching to C++/CLR seemed to me (pleased correct me if I'm wrong) that I'm bound to a certain platform (32bit) and I have to compile two assemblies when I let the application run on another platform (64bit). Is this true? So asked shortly: How is it possible to add two arrays of two different types in a fast way. Is it true that the developers of C# haven't thought about this. Switching to a different language (C# - C++) seems not to be an option. I realize that simply performing this operation float []A = new float[]{1,2,3}; byte []B = new byte[]{1,2,3}; float []C = A+B; is not possible and unnecessary although it would be nice if it would work. My solution I was trying was following: public static class ArrayExt { public static unsafe TResult[] Add<T1, T2, TResult>(T1 []A, T2 []B) { // Assume the length of both arrays is equal TResult[] result = new TResult[A.Length]; GCHandle h1 = GCHandle.Alloc (A, Pinned); GCHandle h2 = GCHandle.Alloc (B, Pinned); GCHandle hR = GCHandle.Alloc (C, Pinned); void *ptrA = h1.ToPointer(); void *ptrB = h2.ToPointer(); void *ptrR = hR.ToPointer(); for (int i=0; i<A.Length; i++) { *((TResult *)ptrR) = (TResult *)((T1)*ptrA + (T2)*ptrB)); } h1.Free(); h2.Free(); hR.Free(); return result; } } Please excuse if the code above is not quite correct, I wrote it without using an C# editor. Is such a solution a shown above thinkable? Please feel free to ask if I made a mistake or described some things incompletely. Thanks for your help Martin

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  • Printing an array in a method, from a different class?

    - by O.Lodhi
    Hello All, I'm a fairly inexperienced programmer, and i'm currently working on a Console Application project. It's basically a little 'mathematics game'; the application generates two random numbers, that have either been added, subtracted, multiplied or divided against each other randomly. The answer is shown on screen and the user has to pick from the menu which is the right mathematical operator, once the correct answer is picked the application then displays on screen how long it took for the user in milliseconds to input the correct answer. Now I want to save the times of the players in an array that can be called up later with all the scores. I need to include a method in this programme and I figured a method to save the times into an array would be suitable. I seem to have stumbled across a little problem though. I'm not quite sure what's wrong: using System; using System.Collections.Generic; using System.Linq; using System.Text; namespace Mathgame { class Program { } class arrayclass { public static void saveInArray(int duration) { int[] TopTenScores = {000,1000,2000,3000,4000,5000,6000,7000,8000,9000}; if (duration < 1000) { duration = TopTenScores[000]; } else if ((duration >= 1000) && (duration <= 1999)) { duration = TopTenScores[1000]; } else if ((duration >= 2000) && (duration <= 2999)) { duration = TopTenScores[2000]; } else if ((duration >= 3000) && (duration <= 3999)) { duration = TopTenScores[3000]; } else if ((duration >= 4000) && (duration <= 4999)) { duration = TopTenScores[4000]; } else if ((duration >= 5000) && (duration <= 5999)) { duration = TopTenScores[5000]; } else if ((duration >= 6000) && (duration <= 6999)) { duration = TopTenScores[6000]; } else if ((duration >= 7000) && (duration <= 7999)) { duration = TopTenScores[7000]; } else if ((duration >= 8000) && (duration <= 8999)) { duration = TopTenScores[8000]; } else if ((duration >= 9000) && (duration <= 9999)) { duration = TopTenScores[9000]; } Console.WriteLine(TopTenScores); } static void Main(string[] args) { int intInput, num1, num2, incorrect, array1; float answer; string input; System.Random randNum = new System.Random(); Console.WriteLine("Welcome to the Maths game!"); Console.WriteLine("(Apologies for the glitchiness!)"); Console.WriteLine(); Console.WriteLine("Please choose from the following options:"); Console.WriteLine(); retry: Console.WriteLine("1 - Test your Maths against the clock!"); Console.WriteLine("2 - Exit the application."); Console.WriteLine("3 - Top scores"); Console.WriteLine(); input = Console.ReadLine(); intInput = int.Parse(input); if (intInput == 1) { goto start; } else if (intInput == 2) { goto fin; } else if (intInput == 3) { array1 = array1.saveInArray; goto retry; } Now, in the last 'else if' statement in the code, you can see my variable array1 trying to call the method, but no matter what I do I keep getting errors. This is the only error I have at the moment, but I have a feeling soon as I resolve that error, another will come up. For now i'm just determined to get past this error: 'int' does not contain a definition for 'saveInArray' and no extension method 'saveInArray' accepting a first argument of type 'int' could be found (are you missing a using directive or an assembly reference?). Any help would be kindly appreciated, apologies in advanced for my ugly written code! And thank you to any help that I receive! Regards, Omar.

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  • Searching a set of data with multiple terms using Linq

    - by Cj Anderson
    I'm in the process of moving from ADO.NET to Linq. The application is a directory search program to look people up. The users are allowed to type the search criteria into a single textbox. They can separate each term with a space, or wrap a phrase in quotes such as "park place" to indicate that it is one term. Behind the scenes the data comes from a XML file that has about 90,000 records in it and is about 65 megs. I load the data into a DataTable and then use the .Select method with a SQL query to perform the searches. The query I pass is built from the search terms the user passed. I split the string from the textbox into an array using a regular expression that will split everything into a separate element that has a space in it. However if there are quotes around a phrase, that becomes it's own element in the array. I then end up with a single dimension array with x number of elements, which I iterate over to build a long query. I then build the search expression below: query = query & _ "((userid LIKE '" & tempstr & "%') OR " & _ "(nickname LIKE '" & tempstr & "%') OR " & _ "(lastname LIKE '" & tempstr & "%') OR " & _ "(firstname LIKE '" & tempstr & "%') OR " & _ "(department LIKE '" & tempstr & "%') OR " & _ "(telephoneNumber LIKE '" & tempstr & "%') OR " & _ "(email LIKE '" & tempstr & "%') OR " & _ "(Office LIKE '" & tempstr & "%'))" Each term will have a set of the above query. If there is more than one term, I put an AND in between, and build another query like above with the next term. I'm not sure how to do this in Linq. So far, I've got the XML file loading correctly. I'm able to search it with specific criteria, but I'm not sure how to best implement the search over multiple terms. 'this works but far too simple to get the job done Dim results = From c In m_DataSet...<Users> _ Where c.<userid>.Value = "XXXX" _ Select c The above code also doesn't use the LIKE operator either. So partial matches don't work. It looks like what I'd want to use is the .Startswith but that appears to be only in Linq2SQL. Any guidance would be appreciated. I'm new to Linq, so I might be missing a simple way to do this. The XML file looks like so: <?xml version="1.0" standalone="yes"?> <theusers> <Users> <userid>person1</userid> <nickname></nickname> <lastname></lastname> <firstname></firstname> <department></department> <telephoneNumber></telephoneNumber> <email></email> </Users> <Users> <userid>person2</userid> <nickname></nickname> <lastname></lastname> <firstname></firstname> <department></department> <telephoneNumber></telephoneNumber> <email></email> </Users>

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  • C++ destructor seems to be called 'early'

    - by suicideducky
    Please see the "edit" section for the updated information. Sorry for yet another C++ dtor question... However I can't seem to find one exactly like mine as all the others are assigning to STL containers (that will delete objects itself) whereas mine is to an array of pointers. So I have the following code fragment #include<iostream> class Block{ public: int x, y, z; int type; Block(){ x=1; y=2; z=3; type=-1; } }; template <class T> class Octree{ T* children[8]; public: ~Octree(){ for( int i=0; i<8; i++){ std::cout << "del:" << i << std::endl; delete children[i]; } } Octree(){ for( int i=0; i<8; i++ ) children[i] = new T; } // place newchild in array at [i] void set_child(int i, T* newchild){ children[i] = newchild; } // return child at [i] T* get_child(int i){ return children[i]; } // place newchild at [i] and return the old [i] T* swap_child(int i, T* newchild){ T* p = children[i]; children[i] = newchild; return p; } }; int main(){ Octree< Octree<Block> > here; std::cout << "nothing seems to have broken" << std::endl; } Looking through the output I notice that the destructor is being called many times before I think it should (as Octree is still in scope), the end of the output also shows: del:0 del:0 del:1 del:2 del:3 Process returned -1073741819 (0xC0000005) execution time : 1.685 s Press any key to continue. For some reason the destructor is going through the same point in the loop twice (0) and then dying. All of this occures before the "nothing seems to have gone wrong" line which I expected before any dtor was called. Thanks in advance :) EDIT The code I posted has some things removed that I thought were unnecessary but after copying and compiling the code I pasted I no longer get the error. What I removed was other integer attributes of the code. Here is the origional: #include<iostream> class Block{ public: int x, y, z; int type; Block(){ x=1; y=2; z=3; type=-1; } Block(int xx, int yy, int zz, int ty){ x=xx; y=yy; z=zz; type=ty; } Block(int xx, int yy, int zz){ x=xx; y=yy; z=zz; type=0; } }; template <class T> class Octree{ int x, y, z; int size; T* children[8]; public: ~Octree(){ for( int i=0; i<8; i++){ std::cout << "del:" << i << std::endl; delete children[i]; } } Octree(int xx, int yy, int zz, int size){ x=xx; y=yy; z=zz; size=size; for( int i=0; i<8; i++ ) children[i] = new T; } Octree(){ Octree(0, 0, 0, 10); } // place newchild in array at [i] void set_child(int i, T* newchild){ children[i] = newchild; } // return child at [i] T* get_child(int i){ return children[i]; } // place newchild at [i] and return the old [i] T* swap_child(int i, T* newchild){ T* p = children[i]; children[i] = newchild; return p; } }; int main(){ Octree< Octree<Block> > here; std::cout << "nothing seems to have broken" << std::endl; } Also, as for the problems with set_child, get_child and swap_child leading to possible memory leaks this will be solved as a wrapper class will either use get before set or use swap to get the old child and write this out to disk before freeing the memory itself. I am glad that it is not my memory management failing but rather another error. I have not made a copy and/or assignment operator yet as I was just testing the block tree out, I will almost certainly make them all private very soon. This version spits out -1073741819. Thank you all for your suggestions and I apologise for highjacking my own thread :$

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  • Using a boost::fusion::map in boost::spirit::karma

    - by user1097105
    I am using boost spirit to parse some text files into a data structure and now I am beginning to generate text from this data structure (using spirit karma). One attempt at a data structure is a boost::fusion::map (as suggested in an answer to this question). But although I can use boost::spirit::qi::parse() and get data in it easily, when I tried to generate text from it using karma, I failed. Below is my attempt (look especially at the "map_data" type). After some reading and playing around with other fusion types, I found boost::fusion::vector and BOOST_FUSION_DEFINE_ASSOC_STRUCT. I succeeded to generate output with both of them, but they don't seem ideal: in vector you cannot access a member using a name (it is like a tuple) -- and in the other solution, I don't think I need both ways (member name and key type) to access the members. #include <iostream> #include <string> #include <boost/spirit/include/karma.hpp> #include <boost/fusion/include/map.hpp> #include <boost/fusion/include/make_map.hpp> #include <boost/fusion/include/vector.hpp> #include <boost/fusion/include/as_vector.hpp> #include <boost/fusion/include/transform.hpp> struct sb_key; struct id_key; using boost::fusion::pair; typedef boost::fusion::map < pair<sb_key, int> , pair<id_key, unsigned long> > map_data; typedef boost::fusion::vector < int, unsigned long > vector_data; #include <boost/fusion/include/define_assoc_struct.hpp> BOOST_FUSION_DEFINE_ASSOC_STRUCT( (), assocstruct_data, (int, a, sb_key) (unsigned long, b, id_key)) namespace karma = boost::spirit::karma; template <typename X> std::string to_string ( const X& data ) { std::string generated; std::back_insert_iterator<std::string> sink(generated); karma::generate_delimited ( sink, karma::int_ << karma::ulong_, karma::space, data ); return generated; } int main() { map_data d1(boost::fusion::make_map<sb_key, id_key>(234, 35314988526ul)); vector_data d2(boost::fusion::make_vector(234, 35314988526ul)); assocstruct_data d3(234,35314988526ul); std::cout << "map_data as_vector: " << boost::fusion::as_vector(d1) << std::endl; //std::cout << "map_data to_string: " << to_string(d1) << std::endl; //*FAIL No 1* std::cout << "at_key (sb_key): " << boost::fusion::at_key<sb_key>(d1) << boost::fusion::at_c<0>(d1) << std::endl << std::endl; std::cout << "vector_data: " << d2 << std::endl; std::cout << "vector_data to_string: " << to_string(d2) << std::endl << std::endl; std::cout << "assoc_struct as_vector: " << boost::fusion::as_vector(d3) << std::endl; std::cout << "assoc_struct to_string: " << to_string(d3) << std::endl; std::cout << "at_key (sb_key): " << boost::fusion::at_key<sb_key>(d3) << d3.a << boost::fusion::at_c<0>(d3) << std::endl; return 0; } Including the commented line gives lots of pages of compilation errors, among which notably something like: no known conversion for argument 1 from ‘boost::fusion::pair’ to ‘double’ no known conversion for argument 1 from ‘boost::fusion::pair’ to ‘float’ Might it be that to_string needs the values of the map_data, and not the pairs? Though I am not good with templates, I tried to get a vector from a map using transform in the following way template <typename P> struct take_second { typename P::second_type operator() (P p) { return p.second; } }; // ... inside main() pair <char, int> ff(32); std::cout << "take_second (expect 32): " << take_second<pair<char,int>>()(ff) << std::endl; std::cout << "transform map_data and to_string: " << to_string(boost::fusion::transform(d1, take_second<>())); //*FAIL No 2* But I don't know what types am I supposed to give when instantiating take_second and anyway I think there must be an easier way to get (iterate over) the values of a map (is there?) If you answer this question, please also give your opinion on whether using an ASSOC_STRUCT or a map is better.

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  • Parse a text file into multiple text file

    - by Vijay Kumar Singh
    I want to get multiple file by parsing a input file Through Java. The Input file contains many fasta format of thousands of protein sequence and I want to generate raw format(i.e., without any comma semicolon and without any extra symbol like "", "[", "]" etc) of each protein sequence. A fasta sequence starts form "" symbol followed by description of protein and then sequence of protein. For example ? lcl|NC_000001.10_cdsid_XP_003403591.1 [gene=LOC100652771] [protein=hypothetical protein LOC100652771] [protein_id=XP_003403591.1] [location=join(12190..12227,12595..12721,13403..13639)] MSESINFSHNLGQLLSPPRCVVMPGMPFPSIRSPELQKTTADLDHTLVSVPSVAESLHHPEITFLTAFCL PSFTRSRPLPDRQLHHCLALCPSFALPAGDGVCHGPGLQGSCYKGETQESVESRVLPGPRHRH Like above formate the input file contains 1000s of protein sequence. I have to generate thousands of raw file containing only individual protein sequence without any special symbol or gaps. I have developed the code for it in Java but out put is : Cannot open a file followed by cannot find file. Please help me to solve my problem. Regards Vijay Kumar Garg Varanasi Bharat (India) The code is /*Java code to convert FASTA format to a raw format*/ import java.io.*; import java.util.*; import java.util.regex.*; import java.io.FileInputStream; // java package for using regular expression public class Arrayren { public static void main(String args[]) throws IOException { String a[]=new String[1000]; String b[][] =new String[1000][1000]; /*open the id file*/ try { File f = new File ("input.txt"); //opening the text document containing genbank ids FileInputStream fis = new FileInputStream("input.txt"); //Reading the file contents through inputstream BufferedInputStream bis = new BufferedInputStream(fis); // Writing the contents to a buffered stream DataInputStream dis = new DataInputStream(bis); //Method for reading Java Standard data types String inputline; String line; String separator = System.getProperty("line.separator"); // reads a line till next line operator is found int i=0; while ((inputline=dis.readLine()) != null) { i++; a[i]=inputline; a[i]=a[i].replaceAll(separator,""); //replaces unwanted patterns like /n with space a[i]=a[i].trim(); // trims out if any space is available a[i]=a[i]+".txt"; //takes the file name into an array try // to handle run time error /*take the sequence in to an array*/ { BufferedReader in = new BufferedReader (new FileReader(a[i])); String inline = null; int j=0; while((inline=in.readLine()) != null) { j++; b[i][j]=inline; Pattern q=Pattern.compile(">"); //Compiling the regular expression Matcher n=q.matcher(inline); //creates the matcher for the above pattern if(n.find()) { /*appending the comment line*/ b[i][j]=b[i][j].replaceAll(">gi",""); //identify the pattern and replace it with a space b[i][j]=b[i][j].replaceAll("[a-zA-Z]",""); b[i][j]=b[i][j].replaceAll("|",""); b[i][j]=b[i][j].replaceAll("\\d{1,15}",""); b[i][j]=b[i][j].replaceAll(".",""); b[i][j]=b[i][j].replaceAll("_",""); b[i][j]=b[i][j].replaceAll("\\(",""); b[i][j]=b[i][j].replaceAll("\\)",""); } /*printing the sequence in to a text file*/ b[i][j]=b[i][j].replaceAll(separator,""); b[i][j]=b[i][j].trim(); // trims out if any space is available File create = new File(inputline+"R.txt"); try { if(!create.exists()) { create.createNewFile(); // creates a new file } else { System.out.println("file already exists"); } } catch(IOException e) // to catch the exception and print the error if cannot open a file { System.err.println("cannot create a file"); } BufferedWriter outt = new BufferedWriter(new FileWriter(inputline+"R.txt", true)); outt.write(b[i][j]); // printing the contents to a text file outt.close(); // closing the text file System.out.println(b[i][j]); } } catch(Exception e) { System.out.println("cannot open a file"); } } } catch(Exception ex) // catch the exception and prints the error if cannot find file { System.out.println("cannot find file "); } } } If you provide me correct it will be much easier to understand.

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  • Help modify a javascript code to perform a div scroll

    - by Jamex
    Hi, The code below uses javascript to smoothly scroll content in a div. I don't need the smooth scrolling action, and only need the onclick action for the buttons. I would like to use this code so that if a scroll up/down button is pressed, the scroll would instantaneously jump up/down to a position, just like if you were to press the reset button (see demo link). If the down button is pressed, it would jump down the position of the content div (say 300px) and show the text instantaneously without showing how the scrolling text. I am not familiar with JS, so it you know a shorter way, please suggest. TIA the demo link is HERE The code is > this.easyscroll = function(){ // id of the container element var > id = "myContent"; // navigation > buttons text var nav = ["Scroll Up", > "Scroll Down", "Reset"]; // id for > each navigation button (OPTIONAL) var > navId = ["btnUp", "btnDown", > "btnReset"]; > > // movement speed var speed = 5; > // desired height of the container > element (in pixels) var height = 200; > // // END CONFIG // do not edit > below this line (unless you want to of > course :) ) // > > var obj = > document.getElementById(id); obj.up > = false; obj.down = false; obj.fast = false; > > var container = > document.createElement("div"); var > parent = obj.parentNode; > container.id="easyscroll"; > parent.insertBefore(container,obj); > parent.removeChild(obj); > container.style.position = > "relative"; container.style.height = > height + "px"; > container.style.overflow = "hidden"; > obj.style.position = "absolute"; > obj.style.top = "0"; obj.style.left > = "0"; container.appendChild(obj); var btns = new Array(); var ul = > document.createElement("ul"); > ul.id="easyscrollnav"; for (var > i=0;i<nav.length;i++){ var li = > document.createElement("li"); > li.innerHTML = nav[i]; li.id = > navId[i]; btns.push(li); > ul.appendChild(li); }; > parent.insertBefore(ul,container); > btns[0].onmouseover = function(){ > obj.up = true; this.className = > "over"; }; btns[0].onmouseout = > function(){ obj.up = false; > this.className = ""; }; > btns[1].onmouseover = function(){ > obj.down = true; this.className = > "over"; }; btns[1].onmouseout = > function(){ obj.down = false; > this.className = ""; }; > btns[0].onmousedown = > btns[1].onmousedown = function(){ > obj.fast = true; }; > btns[0].onmouseup = btns[1].onmouseup > = function(){ obj.fast = false; }; btns[2].onmouseover = > function(){ this.className = > "over"; }; btns[2].onmouseout = > function(){ this.className = ""; > }; btns[2].onclick = function(){ > obj.style.top = "0px"; }; > this.start = function(){ var newTop; var objHeight = > obj.offsetHeight; var top = > obj.offsetTop; var fast = (obj.fast) > ? 2 : 1; if(obj.down){ newTop > = ((objHeight+top) > height) ? top-(speed*fast) : top; > obj.style.top = newTop + "px"; > }; if(obj.up){ newTop = > (top < 0) ? top+(speed*fast) : top; > obj.style.top = newTop + "px"; }; > }; obj.interval = > setInterval("start()",50); }; > > > this.addEvent = function(obj,type,fn){ > if(obj.attachEvent){ > obj['e'+type+fn] = fn; > obj[type+fn] = > function(){obj['e'+type+fn](window.event > );} obj.attachEvent('on'+type, > obj[type+fn]); } else { > obj.addEventListener(type,fn,false); > }; }; > addEvent(window,"load",easyscroll);

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  • Update table rows in a non-sequential way using the output of a php script

    - by moviemaniac
    Good evening everybody, this is my very first question and I hope I've done my search in stack's archive at best!!! I need to monitor several devices by querying theyr mysql database and gather some informations. Then these informations are presented to the operator in an html table. I have wrote a php script wich loads devices from a multidimensional array, loops through the array and gather data and create the table. The table structure is the following: <table id="monitoring" class="rt cf"> <thead class="cf"> <tr> <th>Device</th> <th>Company</th> <th>Data1</th> <th>Data2</th> <th>Data3</th> <th>Data4</th> <th>Data5</th> <th>Data6</th> <th>Data7</th> <th>Data8</th> <th>Data9</th> </tr> </thead> <tbody> <tr id="Device1"> <td>Devide 1 name</td> <td>xx</td> <td><img src="/path_to_images/ajax_loader.gif" width="24px" /></td> <td>&nbsp;</td> <td>&nbsp;</td> <td>&nbsp;</td> <td>&nbsp;</td> <td>&nbsp;</td> <td>&nbsp;</td> <td>&nbsp;</td> <td>&nbsp;</td> </tr> <tr id="Device2"> <td>Devide 1 name</td> <td>xx</td> <td><img src="/path_to_images/ajax_loader.gif" width="24px" /></td> <td>&nbsp;</td> <td>&nbsp;</td> <td>&nbsp;</td> <td>&nbsp;</td> <td>&nbsp;</td> <td>&nbsp;</td> <td>&nbsp;</td> <td>&nbsp;</td> </tr> <tr id="DeviceN"> <td>Devide 1 name</td> <td>xx</td> <td><img src="/path_to_images/ajax_loader.gif" width="24px" /></td> <td>&nbsp;</td> <td>&nbsp;</td> <td>&nbsp;</td> <td>&nbsp;</td> <td>&nbsp;</td> <td>&nbsp;</td> <td>&nbsp;</td> <td>&nbsp;</td> </tr> </tbody> </table> The above table is directly populated when I first load the page; then, with a very simple function, i update this table every minute without reloading the page: <script> var auto_refresh = setInterval( function() { jQuery("#monitoring").load('/overview.php').fadeIn("slow"); var UpdateTime= new Date(); var StrUpdateTime; StrUpdateTime= ('0' + UpdateTime.getHours()).slice(-2) + ':' + ('0' + UpdateTime.getMinutes()).slice(-2) + ':' + ('0' + UpdateTime.getSeconds()).slice(-2); jQuery("#progress").text("Updated on: " + StrUpdateTime); }, 60000); </script> The above code runs in a wordpress environment. It comes out that when devices are too much and internet connection is not that fast, the script times out, even if i dramatically increase the timeout period. So it is impossible even to load the page the first time... Therefore I would like to change my code so that I can handle each row as a single entity, with its own refresh period. So when the user first loads the page, he sees n rows (one per device) with the ajax loader image... then an update cycle should start independently for each row, so that the user sees data gathered from each database... then ajax loader when the script is trying to retrieve data, then the gathered data once it has been collected or an error message stating that it is not possible to gather data since hour xx:yy:zz. So rows updating should be somewhat independent from the others, like if each row updating was a single closed process. So that rows updating is not done sequentially from the first row to the last. I hope I've sufficiently detailed my problem. Currently I feel like I am at a dead-end. Could someone please show me somewhere to start from?

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  • How to use Devicemotion/Gyroscope to move a dot from center to 8 directions of iphone screen

    - by iSeeker
    I am trying to move a dot at center to 8 directions of iphone screen using Devicemotion such that it moves faster when tilted at a faster rate. Rough sketch is below: I could find a similar implementation in an app called Gyrododge in appstore, i cant figure out how to make it work... Update: This is what i have done so far, but the response is not smooth, and is very jittery.. xdiff and ydiff are the change of device attitude in x and y directions, derived from quatenion implementation. if (currDeviceMotion.rotationRate.x < -2) { NSLog(@"To Top"); if (195+800*ydiff >=193 && 195+800*ydiff <= 197) { [self.pitchDot setFrame:CGRectMake(150, 195, 20, 20)]; }else{ if (195+800*ydiff >=390 ) { [self.pitchDot setFrame:CGRectMake(150, 390, 20, 20)]; }else if (195+800*ydiff <= 0){ [self.pitchDot setFrame:CGRectMake(150, 0, 20, 20)]; }else if(195+800*ydiff < 194){ [self.pitchDot setFrame:CGRectMake(150, 195+800*ydiff, 20, 20)]; }else if(195+800*ydiff > 196){ [self.pitchDot setFrame:CGRectMake(150, 195+800*ydiff, 20, 20)]; } } }else if (currDeviceMotion.rotationRate.x > 2){ NSLog(@"To Bottom"); if (195+800*ydiff >=193 && 195+800*ydiff <= 197) { [self.pitchDot setFrame:CGRectMake(150, 195, 20, 20)]; }else{ if (195+800*ydiff >=390 ) { [self.pitchDot setFrame:CGRectMake(150, 390, 20, 20)]; }else if (195+800*ydiff <= 0){ [self.pitchDot setFrame:CGRectMake(150, 0, 20, 20)]; }else if(195+800*ydiff < 194){ [self.pitchDot setFrame:CGRectMake(150, 195+800*ydiff, 20, 20)]; }else if(195+800*ydiff > 196){ [self.pitchDot setFrame:CGRectMake(150, 195+800*ydiff, 20, 20)]; } } }else if (currDeviceMotion.rotationRate.y < -2){ NSLog(@"To Left"); if (150+500*xdiff >= 148 && 150+500*xdiff <=152) { [self.pitchDot setFrame:CGRectMake(150, 195, 20, 20)]; }else{ if (150+500*xdiff >= 300 ) { [self.pitchDot setFrame:CGRectMake(300, 195, 20, 20)]; }else if (150+500*xdiff <= 0){ [self.pitchDot setFrame:CGRectMake(0, 195, 20, 20)]; }else if(150+500*xdiff < 148){ [self.pitchDot setFrame:CGRectMake(150+500*xdiff, 195, 20, 20)]; }else if(150+500*xdiff > 152){ [self.pitchDot setFrame:CGRectMake(150+500*xdiff, 195, 20, 20)]; } } }else if (currDeviceMotion.rotationRate.y > 2){ NSLog(@"To Right"); if (150+500*xdiff >= 148 && 150+500*xdiff <=152) { [self.pitchDot setFrame:CGRectMake(150, 195, 20, 20)]; }else{ if (150+500*xdiff >= 300 ) { [self.pitchDot setFrame:CGRectMake(300, 195, 20, 20)]; }else if (150+500*xdiff <= 0){ [self.pitchDot setFrame:CGRectMake(0, 195, 20, 20)]; }else if(150+500*xdiff < 148){ [self.pitchDot setFrame:CGRectMake(150+500*xdiff, 195, 20, 20)]; }else if(150+500*xdiff > 152){ [self.pitchDot setFrame:CGRectMake(150+500*xdiff, 195, 20, 20)]; } } }else if (currDeviceMotion.rotationRate.x < -0.20 && currDeviceMotion.rotationRate.y > 0.20 ){ NSLog(@"To Diagonal Right Top"); if (150+650*xdiff >= 148 && 150+650*xdiff <=152) { [self.pitchDot setFrame:CGRectMake(150, 195, 20, 20)]; }else{ if (150+650*xdiff >= 300 ) { [self.pitchDot setFrame:CGRectMake(300, 0, 20, 20)]; }else if(150+650*xdiff > 152){ [self.pitchDot setFrame:CGRectMake(150+650*xdiff, 195-1.3*650*xdiff, 20, 20)]; } } }else if (currDeviceMotion.rotationRate.x > 0.20 && currDeviceMotion.rotationRate.y < -0.20 ){ NSLog(@"To Diagonal Left Bottom"); if (150+650*xdiff >= 148 && 150+650*xdiff <=152) { [self.pitchDot setFrame:CGRectMake(150, 195, 20, 20)]; }else{ if (150+650*xdiff <= 0 ) { [self.pitchDot setFrame:CGRectMake(0, 390, 20, 20)]; }else if(150+650*xdiff < 148){ [self.pitchDot setFrame:CGRectMake(150+650*xdiff, 195-1.3*650*xdiff, 20, 20)]; } } }else if (currDeviceMotion.rotationRate.x < -0.20 && currDeviceMotion.rotationRate.y < -0.20 ){ NSLog(@"To Diagonal Left Top and xdiff is %f",xdiff); if (150+650*xdiff >= 148 && 150+650*xdiff <=152) { [self.pitchDot setFrame:CGRectMake(150, 195, 20, 20)]; }else{ if (150+650*xdiff <= 0 ) { [self.pitchDot setFrame:CGRectMake(0, 0, 20, 20)]; }else if(150+650*xdiff < 148){ [self.pitchDot setFrame:CGRectMake(150+650*xdiff, 195+1.3*650*xdiff, 20, 20)]; } } }else if (currDeviceMotion.rotationRate.x > 0.20 && currDeviceMotion.rotationRate.y > 0.20 ){ NSLog(@"To Diagonal Right Bottom"); if (150+650*xdiff >= 148 && 150+650*xdiff <=152) { [self.pitchDot setFrame:CGRectMake(150, 195, 20, 20)]; }else{ if (150+650*xdiff >= 300 ) { [self.pitchDot setFrame:CGRectMake(300, 390, 20, 20)]; }else if(150+650*xdiff > 152){ [self.pitchDot setFrame:CGRectMake(150+650*xdiff, 195+1.3*650*xdiff, 20, 20)]; } } }else if((currDeviceMotion.rotationRate.x < 0.20 && currDeviceMotion.rotationRate.x < -0.20) ||(currDeviceMotion.rotationRate.y < 0.20 && currDeviceMotion.rotationRate.y < -0.20) ||(currDeviceMotion.rotationRate.z < 0.20 && currDeviceMotion.rotationRate.z < -0.20)){ [self.rollDot setFrame:CGRectMake(150, 195, 20, 20)]; [self.pitchDot setFrame:CGRectMake(150, 195, 20, 20)]; } It could be great if i could make it move like the application i have stated above, called Gyrododge This link also addresses a similar question:Link. Any advice or help is greatly appreciated... Thanks.

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  • Inheritance Mapping Strategies with Entity Framework Code First CTP5: Part 3 – Table per Concrete Type (TPC) and Choosing Strategy Guidelines

    - by mortezam
    This is the third (and last) post in a series that explains different approaches to map an inheritance hierarchy with EF Code First. I've described these strategies in previous posts: Part 1 – Table per Hierarchy (TPH) Part 2 – Table per Type (TPT)In today’s blog post I am going to discuss Table per Concrete Type (TPC) which completes the inheritance mapping strategies supported by EF Code First. At the end of this post I will provide some guidelines to choose an inheritance strategy mainly based on what we've learned in this series. TPC and Entity Framework in the Past Table per Concrete type is somehow the simplest approach suggested, yet using TPC with EF is one of those concepts that has not been covered very well so far and I've seen in some resources that it was even discouraged. The reason for that is just because Entity Data Model Designer in VS2010 doesn't support TPC (even though the EF runtime does). That basically means if you are following EF's Database-First or Model-First approaches then configuring TPC requires manually writing XML in the EDMX file which is not considered to be a fun practice. Well, no more. You'll see that with Code First, creating TPC is perfectly possible with fluent API just like other strategies and you don't need to avoid TPC due to the lack of designer support as you would probably do in other EF approaches. Table per Concrete Type (TPC)In Table per Concrete type (aka Table per Concrete class) we use exactly one table for each (nonabstract) class. All properties of a class, including inherited properties, can be mapped to columns of this table, as shown in the following figure: As you can see, the SQL schema is not aware of the inheritance; effectively, we’ve mapped two unrelated tables to a more expressive class structure. If the base class was concrete, then an additional table would be needed to hold instances of that class. I have to emphasize that there is no relationship between the database tables, except for the fact that they share some similar columns. TPC Implementation in Code First Just like the TPT implementation, we need to specify a separate table for each of the subclasses. We also need to tell Code First that we want all of the inherited properties to be mapped as part of this table. In CTP5, there is a new helper method on EntityMappingConfiguration class called MapInheritedProperties that exactly does this for us. Here is the complete object model as well as the fluent API to create a TPC mapping: public abstract class BillingDetail {     public int BillingDetailId { get; set; }     public string Owner { get; set; }     public string Number { get; set; } }          public class BankAccount : BillingDetail {     public string BankName { get; set; }     public string Swift { get; set; } }          public class CreditCard : BillingDetail {     public int CardType { get; set; }     public string ExpiryMonth { get; set; }     public string ExpiryYear { get; set; } }      public class InheritanceMappingContext : DbContext {     public DbSet<BillingDetail> BillingDetails { get; set; }              protected override void OnModelCreating(ModelBuilder modelBuilder)     {         modelBuilder.Entity<BankAccount>().Map(m =>         {             m.MapInheritedProperties();             m.ToTable("BankAccounts");         });         modelBuilder.Entity<CreditCard>().Map(m =>         {             m.MapInheritedProperties();             m.ToTable("CreditCards");         });                 } } The Importance of EntityMappingConfiguration ClassAs a side note, it worth mentioning that EntityMappingConfiguration class turns out to be a key type for inheritance mapping in Code First. Here is an snapshot of this class: namespace System.Data.Entity.ModelConfiguration.Configuration.Mapping {     public class EntityMappingConfiguration<TEntityType> where TEntityType : class     {         public ValueConditionConfiguration Requires(string discriminator);         public void ToTable(string tableName);         public void MapInheritedProperties();     } } As you have seen so far, we used its Requires method to customize TPH. We also used its ToTable method to create a TPT and now we are using its MapInheritedProperties along with ToTable method to create our TPC mapping. TPC Configuration is Not Done Yet!We are not quite done with our TPC configuration and there is more into this story even though the fluent API we saw perfectly created a TPC mapping for us in the database. To see why, let's start working with our object model. For example, the following code creates two new objects of BankAccount and CreditCard types and tries to add them to the database: using (var context = new InheritanceMappingContext()) {     BankAccount bankAccount = new BankAccount();     CreditCard creditCard = new CreditCard() { CardType = 1 };                      context.BillingDetails.Add(bankAccount);     context.BillingDetails.Add(creditCard);     context.SaveChanges(); } Running this code throws an InvalidOperationException with this message: The changes to the database were committed successfully, but an error occurred while updating the object context. The ObjectContext might be in an inconsistent state. Inner exception message: AcceptChanges cannot continue because the object's key values conflict with another object in the ObjectStateManager. Make sure that the key values are unique before calling AcceptChanges. The reason we got this exception is because DbContext.SaveChanges() internally invokes SaveChanges method of its internal ObjectContext. ObjectContext's SaveChanges method on its turn by default calls AcceptAllChanges after it has performed the database modifications. AcceptAllChanges method merely iterates over all entries in ObjectStateManager and invokes AcceptChanges on each of them. Since the entities are in Added state, AcceptChanges method replaces their temporary EntityKey with a regular EntityKey based on the primary key values (i.e. BillingDetailId) that come back from the database and that's where the problem occurs since both the entities have been assigned the same value for their primary key by the database (i.e. on both BillingDetailId = 1) and the problem is that ObjectStateManager cannot track objects of the same type (i.e. BillingDetail) with the same EntityKey value hence it throws. If you take a closer look at the TPC's SQL schema above, you'll see why the database generated the same values for the primary keys: the BillingDetailId column in both BankAccounts and CreditCards table has been marked as identity. How to Solve The Identity Problem in TPC As you saw, using SQL Server’s int identity columns doesn't work very well together with TPC since there will be duplicate entity keys when inserting in subclasses tables with all having the same identity seed. Therefore, to solve this, either a spread seed (where each table has its own initial seed value) will be needed, or a mechanism other than SQL Server’s int identity should be used. Some other RDBMSes have other mechanisms allowing a sequence (identity) to be shared by multiple tables, and something similar can be achieved with GUID keys in SQL Server. While using GUID keys, or int identity keys with different starting seeds will solve the problem but yet another solution would be to completely switch off identity on the primary key property. As a result, we need to take the responsibility of providing unique keys when inserting records to the database. We will go with this solution since it works regardless of which database engine is used. Switching Off Identity in Code First We can switch off identity simply by placing DatabaseGenerated attribute on the primary key property and pass DatabaseGenerationOption.None to its constructor. DatabaseGenerated attribute is a new data annotation which has been added to System.ComponentModel.DataAnnotations namespace in CTP5: public abstract class BillingDetail {     [DatabaseGenerated(DatabaseGenerationOption.None)]     public int BillingDetailId { get; set; }     public string Owner { get; set; }     public string Number { get; set; } } As always, we can achieve the same result by using fluent API, if you prefer that: modelBuilder.Entity<BillingDetail>()             .Property(p => p.BillingDetailId)             .HasDatabaseGenerationOption(DatabaseGenerationOption.None); Working With The Object Model Our TPC mapping is ready and we can try adding new records to the database. But, like I said, now we need to take care of providing unique keys when creating new objects: using (var context = new InheritanceMappingContext()) {     BankAccount bankAccount = new BankAccount()      {          BillingDetailId = 1                          };     CreditCard creditCard = new CreditCard()      {          BillingDetailId = 2,         CardType = 1     };                      context.BillingDetails.Add(bankAccount);     context.BillingDetails.Add(creditCard);     context.SaveChanges(); } Polymorphic Associations with TPC is Problematic The main problem with this approach is that it doesn’t support Polymorphic Associations very well. After all, in the database, associations are represented as foreign key relationships and in TPC, the subclasses are all mapped to different tables so a polymorphic association to their base class (abstract BillingDetail in our example) cannot be represented as a simple foreign key relationship. For example, consider the the domain model we introduced here where User has a polymorphic association with BillingDetail. This would be problematic in our TPC Schema, because if User has a many-to-one relationship with BillingDetail, the Users table would need a single foreign key column, which would have to refer both concrete subclass tables. This isn’t possible with regular foreign key constraints. Schema Evolution with TPC is Complex A further conceptual problem with this mapping strategy is that several different columns, of different tables, share exactly the same semantics. This makes schema evolution more complex. For example, a change to a base class property results in changes to multiple columns. It also makes it much more difficult to implement database integrity constraints that apply to all subclasses. Generated SQLLet's examine SQL output for polymorphic queries in TPC mapping. For example, consider this polymorphic query for all BillingDetails and the resulting SQL statements that being executed in the database: var query = from b in context.BillingDetails select b; Just like the SQL query generated by TPT mapping, the CASE statements that you see in the beginning of the query is merely to ensure columns that are irrelevant for a particular row have NULL values in the returning flattened table. (e.g. BankName for a row that represents a CreditCard type). TPC's SQL Queries are Union Based As you can see in the above screenshot, the first SELECT uses a FROM-clause subquery (which is selected with a red rectangle) to retrieve all instances of BillingDetails from all concrete class tables. The tables are combined with a UNION operator, and a literal (in this case, 0 and 1) is inserted into the intermediate result; (look at the lines highlighted in yellow.) EF reads this to instantiate the correct class given the data from a particular row. A union requires that the queries that are combined, project over the same columns; hence, EF has to pad and fill up nonexistent columns with NULL. This query will really perform well since here we can let the database optimizer find the best execution plan to combine rows from several tables. There is also no Joins involved so it has a better performance than the SQL queries generated by TPT where a Join is required between the base and subclasses tables. Choosing Strategy GuidelinesBefore we get into this discussion, I want to emphasize that there is no one single "best strategy fits all scenarios" exists. As you saw, each of the approaches have their own advantages and drawbacks. Here are some rules of thumb to identify the best strategy in a particular scenario: If you don’t require polymorphic associations or queries, lean toward TPC—in other words, if you never or rarely query for BillingDetails and you have no class that has an association to BillingDetail base class. I recommend TPC (only) for the top level of your class hierarchy, where polymorphism isn’t usually required, and when modification of the base class in the future is unlikely. If you do require polymorphic associations or queries, and subclasses declare relatively few properties (particularly if the main difference between subclasses is in their behavior), lean toward TPH. Your goal is to minimize the number of nullable columns and to convince yourself (and your DBA) that a denormalized schema won’t create problems in the long run. If you do require polymorphic associations or queries, and subclasses declare many properties (subclasses differ mainly by the data they hold), lean toward TPT. Or, depending on the width and depth of your inheritance hierarchy and the possible cost of joins versus unions, use TPC. By default, choose TPH only for simple problems. For more complex cases (or when you’re overruled by a data modeler insisting on the importance of nullability constraints and normalization), you should consider the TPT strategy. But at that point, ask yourself whether it may not be better to remodel inheritance as delegation in the object model (delegation is a way of making composition as powerful for reuse as inheritance). Complex inheritance is often best avoided for all sorts of reasons unrelated to persistence or ORM. EF acts as a buffer between the domain and relational models, but that doesn’t mean you can ignore persistence concerns when designing your classes. SummaryIn this series, we focused on one of the main structural aspect of the object/relational paradigm mismatch which is inheritance and discussed how EF solve this problem as an ORM solution. We learned about the three well-known inheritance mapping strategies and their implementations in EF Code First. Hopefully it gives you a better insight about the mapping of inheritance hierarchies as well as choosing the best strategy for your particular scenario. Happy New Year and Happy Code-Firsting! References ADO.NET team blog Java Persistence with Hibernate book a { color: #5A99FF; } a:visited { color: #5A99FF; } .title { padding-bottom: 5px; font-family: Segoe UI; font-size: 11pt; font-weight: bold; padding-top: 15px; } .code, .typeName { font-family: consolas; } .typeName { color: #2b91af; } .padTop5 { padding-top: 5px; } .padTop10 { padding-top: 10px; } .exception { background-color: #f0f0f0; font-style: italic; padding-bottom: 5px; padding-left: 5px; padding-top: 5px; padding-right: 5px; }

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  • More CPU cores may not always lead to better performance – MAXDOP and query memory distribution in spotlight

    - by sqlworkshops
    More hardware normally delivers better performance, but there are exceptions where it can hinder performance. Understanding these exceptions and working around it is a major part of SQL Server performance tuning.   When a memory allocating query executes in parallel, SQL Server distributes memory to each task that is executing part of the query in parallel. In our example the sort operator that executes in parallel divides the memory across all tasks assuming even distribution of rows. Common memory allocating queries are that perform Sort and do Hash Match operations like Hash Join or Hash Aggregation or Hash Union.   In reality, how often are column values evenly distributed, think about an example; are employees working for your company distributed evenly across all the Zip codes or mainly concentrated in the headquarters? What happens when you sort result set based on Zip codes? Do all products in the catalog sell equally or are few products hot selling items?   One of my customers tested the below example on a 24 core server with various MAXDOP settings and here are the results:MAXDOP 1: CPU time = 1185 ms, elapsed time = 1188 msMAXDOP 4: CPU time = 1981 ms, elapsed time = 1568 msMAXDOP 8: CPU time = 1918 ms, elapsed time = 1619 msMAXDOP 12: CPU time = 2367 ms, elapsed time = 2258 msMAXDOP 16: CPU time = 2540 ms, elapsed time = 2579 msMAXDOP 20: CPU time = 2470 ms, elapsed time = 2534 msMAXDOP 0: CPU time = 2809 ms, elapsed time = 2721 ms - all 24 cores.In the above test, when the data was evenly distributed, the elapsed time of parallel query was always lower than serial query.   Why does the query get slower and slower with more CPU cores / higher MAXDOP? Maybe you can answer this question after reading the article; let me know: [email protected].   Well you get the point, let’s see an example.   The best way to learn is to practice. To create the below tables and reproduce the behavior, join the mailing list by using this link: www.sqlworkshops.com/ml and I will send you the table creation script.   Let’s update the Employees table with 49 out of 50 employees located in Zip code 2001. update Employees set Zip = EmployeeID / 400 + 1 where EmployeeID % 50 = 1 update Employees set Zip = 2001 where EmployeeID % 50 != 1 go update statistics Employees with fullscan go   Let’s create the temporary table #FireDrill with all possible Zip codes. drop table #FireDrill go create table #FireDrill (Zip int primary key) insert into #FireDrill select distinct Zip from Employees update statistics #FireDrill with fullscan go  Let’s execute the query serially with MAXDOP 1. --Example provided by www.sqlworkshops.com --Execute query with uneven Zip code distribution --First serially with MAXDOP 1 set statistics time on go declare @EmployeeID int, @EmployeeName varchar(48),@zip int select @EmployeeName = e.EmployeeName, @zip = e.Zip from Employees e       inner join #FireDrill fd on (e.Zip = fd.Zip)       order by e.Zip option (maxdop 1) goThe query took 1011 ms to complete.   The execution plan shows the 77816 KB of memory was granted while the estimated rows were 799624.  No Sort Warnings in SQL Server Profiler.  Now let’s execute the query in parallel with MAXDOP 0. --Example provided by www.sqlworkshops.com --Execute query with uneven Zip code distribution --In parallel with MAXDOP 0 set statistics time on go declare @EmployeeID int, @EmployeeName varchar(48),@zip int select @EmployeeName = e.EmployeeName, @zip = e.Zip from Employees e       inner join #FireDrill fd on (e.Zip = fd.Zip)       order by e.Zip option (maxdop 0) go The query took 1912 ms to complete.  The execution plan shows the 79360 KB of memory was granted while the estimated rows were 799624.  The estimated number of rows between serial and parallel plan are the same. The parallel plan has slightly more memory granted due to additional overhead. Sort properties shows the rows are unevenly distributed over the 4 threads.   Sort Warnings in SQL Server Profiler.   Intermediate Summary: The reason for the higher duration with parallel plan was sort spill. This is due to uneven distribution of employees over Zip codes, especially concentration of 49 out of 50 employees in Zip code 2001. Now let’s update the Employees table and distribute employees evenly across all Zip codes.   update Employees set Zip = EmployeeID / 400 + 1 go update statistics Employees with fullscan go  Let’s execute the query serially with MAXDOP 1. --Example provided by www.sqlworkshops.com --Execute query with uneven Zip code distribution --Serially with MAXDOP 1 set statistics time on go declare @EmployeeID int, @EmployeeName varchar(48),@zip int select @EmployeeName = e.EmployeeName, @zip = e.Zip from Employees e       inner join #FireDrill fd on (e.Zip = fd.Zip)       order by e.Zip option (maxdop 1) go   The query took 751 ms to complete.  The execution plan shows the 77816 KB of memory was granted while the estimated rows were 784707.  No Sort Warnings in SQL Server Profiler.   Now let’s execute the query in parallel with MAXDOP 0. --Example provided by www.sqlworkshops.com --Execute query with uneven Zip code distribution --In parallel with MAXDOP 0 set statistics time on go declare @EmployeeID int, @EmployeeName varchar(48),@zip int select @EmployeeName = e.EmployeeName, @zip = e.Zip from Employees e       inner join #FireDrill fd on (e.Zip = fd.Zip)       order by e.Zip option (maxdop 0) go The query took 661 ms to complete.  The execution plan shows the 79360 KB of memory was granted while the estimated rows were 784707.  Sort properties shows the rows are evenly distributed over the 4 threads. No Sort Warnings in SQL Server Profiler.    Intermediate Summary: When employees were distributed unevenly, concentrated on 1 Zip code, parallel sort spilled while serial sort performed well without spilling to tempdb. When the employees were distributed evenly across all Zip codes, parallel sort and serial sort did not spill to tempdb. This shows uneven data distribution may affect the performance of some parallel queries negatively. For detailed discussion of memory allocation, refer to webcasts available at www.sqlworkshops.com/webcasts.     Some of you might conclude from the above execution times that parallel query is not faster even when there is no spill. Below you can see when we are joining limited amount of Zip codes, parallel query will be fasted since it can use Bitmap Filtering.   Let’s update the Employees table with 49 out of 50 employees located in Zip code 2001. update Employees set Zip = EmployeeID / 400 + 1 where EmployeeID % 50 = 1 update Employees set Zip = 2001 where EmployeeID % 50 != 1 go update statistics Employees with fullscan go  Let’s create the temporary table #FireDrill with limited Zip codes. drop table #FireDrill go create table #FireDrill (Zip int primary key) insert into #FireDrill select distinct Zip       from Employees where Zip between 1800 and 2001 update statistics #FireDrill with fullscan go  Let’s execute the query serially with MAXDOP 1. --Example provided by www.sqlworkshops.com --Execute query with uneven Zip code distribution --Serially with MAXDOP 1 set statistics time on go declare @EmployeeID int, @EmployeeName varchar(48),@zip int select @EmployeeName = e.EmployeeName, @zip = e.Zip from Employees e       inner join #FireDrill fd on (e.Zip = fd.Zip)       order by e.Zip option (maxdop 1) go The query took 989 ms to complete.  The execution plan shows the 77816 KB of memory was granted while the estimated rows were 785594. No Sort Warnings in SQL Server Profiler.  Now let’s execute the query in parallel with MAXDOP 0. --Example provided by www.sqlworkshops.com --Execute query with uneven Zip code distribution --In parallel with MAXDOP 0 set statistics time on go declare @EmployeeID int, @EmployeeName varchar(48),@zip int select @EmployeeName = e.EmployeeName, @zip = e.Zip from Employees e       inner join #FireDrill fd on (e.Zip = fd.Zip)       order by e.Zip option (maxdop 0) go The query took 1799 ms to complete.  The execution plan shows the 79360 KB of memory was granted while the estimated rows were 785594.  Sort Warnings in SQL Server Profiler.    The estimated number of rows between serial and parallel plan are the same. The parallel plan has slightly more memory granted due to additional overhead.  Intermediate Summary: The reason for the higher duration with parallel plan even with limited amount of Zip codes was sort spill. This is due to uneven distribution of employees over Zip codes, especially concentration of 49 out of 50 employees in Zip code 2001.   Now let’s update the Employees table and distribute employees evenly across all Zip codes. update Employees set Zip = EmployeeID / 400 + 1 go update statistics Employees with fullscan go Let’s execute the query serially with MAXDOP 1. --Example provided by www.sqlworkshops.com --Execute query with uneven Zip code distribution --Serially with MAXDOP 1 set statistics time on go declare @EmployeeID int, @EmployeeName varchar(48),@zip int select @EmployeeName = e.EmployeeName, @zip = e.Zip from Employees e       inner join #FireDrill fd on (e.Zip = fd.Zip)       order by e.Zip option (maxdop 1) go The query took 250  ms to complete.  The execution plan shows the 9016 KB of memory was granted while the estimated rows were 79973.8.  No Sort Warnings in SQL Server Profiler.  Now let’s execute the query in parallel with MAXDOP 0.  --Example provided by www.sqlworkshops.com --Execute query with uneven Zip code distribution --In parallel with MAXDOP 0 set statistics time on go declare @EmployeeID int, @EmployeeName varchar(48),@zip int select @EmployeeName = e.EmployeeName, @zip = e.Zip from Employees e       inner join #FireDrill fd on (e.Zip = fd.Zip)       order by e.Zip option (maxdop 0) go The query took 85 ms to complete.  The execution plan shows the 13152 KB of memory was granted while the estimated rows were 784707.  No Sort Warnings in SQL Server Profiler.    Here you see, parallel query is much faster than serial query since SQL Server is using Bitmap Filtering to eliminate rows before the hash join.   Parallel queries are very good for performance, but in some cases it can hinder performance. If one identifies the reason for these hindrances, then it is possible to get the best out of parallelism. I covered many aspects of monitoring and tuning parallel queries in webcasts (www.sqlworkshops.com/webcasts) and articles (www.sqlworkshops.com/articles). I suggest you to watch the webcasts and read the articles to better understand how to identify and tune parallel query performance issues.   Summary: One has to avoid sort spill over tempdb and the chances of spills are higher when a query executes in parallel with uneven data distribution. Parallel query brings its own advantage, reduced elapsed time and reduced work with Bitmap Filtering. So it is important to understand how to avoid spills over tempdb and when to execute a query in parallel.   I explain these concepts with detailed examples in my webcasts (www.sqlworkshops.com/webcasts), I recommend you to watch them. The best way to learn is to practice. To create the above tables and reproduce the behavior, join the mailing list at www.sqlworkshops.com/ml and I will send you the relevant SQL Scripts.   Register for the upcoming 3 Day Level 400 Microsoft SQL Server 2008 and SQL Server 2005 Performance Monitoring & Tuning Hands-on Workshop in London, United Kingdom during March 15-17, 2011, click here to register / Microsoft UK TechNet.These are hands-on workshops with a maximum of 12 participants and not lectures. For consulting engagements click here.   Disclaimer and copyright information:This article refers to organizations and products that may be the trademarks or registered trademarks of their various owners. Copyright of this article belongs to R Meyyappan / www.sqlworkshops.com. You may freely use the ideas and concepts discussed in this article with acknowledgement (www.sqlworkshops.com), but you may not claim any of it as your own work. This article is for informational purposes only; you use any of the suggestions given here entirely at your own risk.   Register for the upcoming 3 Day Level 400 Microsoft SQL Server 2008 and SQL Server 2005 Performance Monitoring & Tuning Hands-on Workshop in London, United Kingdom during March 15-17, 2011, click here to register / Microsoft UK TechNet.These are hands-on workshops with a maximum of 12 participants and not lectures. For consulting engagements click here.   R Meyyappan [email protected] LinkedIn: http://at.linkedin.com/in/rmeyyappan  

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  • CodePlex Daily Summary for Monday, March 05, 2012

    CodePlex Daily Summary for Monday, March 05, 2012Popular ReleasesSimple Injector: Simple Injector v1.4.1: This release adds two small improvements to the SimpleInjector.Extensions.dll. No changes have been made to the core library. New features and improvements in this release for the SimpleInjector.Extensions.dll The RegisterManyForOpenGeneric extension methods now accept non-generic decorator, as long as they implement the given open generic service type. GetTypesToRegister methods added to the OpenGenericBatchRegistrationExtensions class which allows to customize the behavior. Note that the...SQL Scriptz Runner: Application: Scriptz Runner source code and applicationCommonLibrary: Code: CodePowerGUI Visual Studio Extension: PowerGUI VSX 1.5.2: Added support for PowerGUI 3.2.Path Copy Copy: 10.0: New version with the following biggest new features: Regular expression support in custom commands (see this work item) Import/export feature for custom commands (see this work item) This version also addresses the following work items: 11353 11348 This version is a recommended upgrade for all users. Note: new custom commands that user regular expressions won't be compatible with earlier versions (if installed by registry manipulation or via network installation), but everything else is ...VidCoder: 1.3.1: Updated HandBrake core to 0.9.6 release (svn 4472). Removed erroneous "None" container choice. Change some logic and help text to stop assuming you have to pick the VIDEO_TS folder for a DVD scan. This should make previewing DVD titles on the Queue Multiple Titles window possible when you've picked the root DVD directory.ASP.NET MVC Framework - Abstracting Data Annotations, HTML5, Knockout JS techs: Version 1.0: Please download the source code. I am not associating any dll for release.ExtAspNet: ExtAspNet v3.1.0: ExtAspNet - ?? ExtJS ??? ASP.NET 2.0 ???,????? AJAX ?????????? ExtAspNet ????? ExtJS ??? ASP.NET 2.0 ???,????? AJAX ??????????。 ExtAspNet ??????? JavaScript,?? CSS,?? UpdatePanel,?? ViewState,?? WebServices ???????。 ??????: IE 7.0, Firefox 3.6, Chrome 3.0, Opera 10.5, Safari 3.0+ ????:Apache License 2.0 (Apache) ??:http://extasp.net/ ??:http://bbs.extasp.net/ ??:http://extaspnet.codeplex.com/ ??:http://sanshi.cnblogs.com/ ????: +2012-03-04 v3.1.0 -??Hidden???????(〓?〓)。 -?PageManager??...AcDown????? - Anime&Comic Downloader: AcDown????? v3.9.1: ?? ●AcDown??????????、??、??????,????1M,????,????,?????????????????????????。???????????Acfun、????(Bilibili)、??、??、YouTube、??、???、??????、SF????、????????????。??????AcPlay?????,??????、????????????????。 ● AcDown???????????????????????????,???,???????????????????。 ● AcDown???????C#??,????.NET Framework 2.0??。?????"Acfun?????"。 ????32??64? Windows XP/Vista/7/8 ????????????? ??:????????Windows XP???,?????????.NET Framework 2.0???(x86),?????"?????????"??? ??????????????,??????????: ??"AcDo...Windows Phone Commands for VS2010: Version 1.0: Initial Release Version 1.0 Connect from device or emulator (Monitors the connection) Show Device information (Plataform, build , version, avaliable memory, total memory, architeture Manager installed applications (Launch, uninstall and explorer isolate storage files) Manager core applications (Launch blocked applications from emulator (Office, Calculator, alarm, calendar , etc) Manager blocked settings from emulator (Airplane Mode, Celullar Network, Wifi, etc) Deploy and update ap...DNN Metro7 style Skin package: Metro7 style Skin for DotNetNuke 06.01.00: Changes on Version 06.01.00 Fixed issue on GraySmallTitle container, that breaks the layout Fixed issue on Blue Metro7 Skin where the Search, Login, Register, Date is missing Fixed issue with the Version numbers on the target file Fixed issue where the jQuery and jQuery-UI files not deleted on upgrade from Version 01.00.00 Added a internal page where the Image Slider would be replaces with a BannerPaneMedia Companion: MC 3.433b Release: General More GUI tweaks (mostly imperceptible!) Updates for mc_com.exe TV The 'Watched' button has been re-instigated Added TV Menu sub-option to search ALL for new Episodes (includes locked shows) Movies Added 'Source' field (eg DVD, Bluray, HDTV), customisable in Advanced Preferences (try it out, let us know how it works!) Added HTML <<format>> tag with optional parameters for video container, source, and resolution (updated HTML tags to be added to Documentation shortly) Known Issu...Picturethrill: Version 2.3.2.0: Release includes Self-Update feature for Picturethrill. What that means for users is that they are always guaranteed to have a fresh copy of Picturethrill on their computers with all latest fixes. When Picturethrill adds a new website to get pictures from, you will get it too!Simple MVVM Toolkit for Silverlight, WPF and Windows Phone: Simple MVVM Toolkit v3.0.0.0: Added support for Silverlight 5.0 and Windows Phone 7.1. Upgraded project templates and samples. Upgraded installer. There are some new prerequisites required for this version, namely Silverlight 5 Tools, Expression Blend Preview for Silverlight 5 (until the SDK is released), Windows Phone 7.1 SDK. Because it is in the experimental band, I have also removed the dependency on the Silverlight Testing Framework. You can use it if you wish, but the Ria Services project template no longer uses ...CODE Framework: 4.0.20301: The latest version adds a number of new features to the WPF system (such as stylable and testable messagebox support) as well as various new features throughout the system (especially in the Utilities namespace).MyRouter (Virtual WiFi Router): MyRouter 1.0.2 (Beta): A friendlier User Interface. A logger file to catch exceptions so you may send it to use to improve and fix any bugs that may occur. A feedback form because we always love hearing what you guy's think of MyRouter. Check for update menu item for you to stay up to date will the latest changes. Facebook fan page so you may spread the word and share MyRouter with friends and family And Many other exciting features were sure your going to love!WPF Sound Visualization Library: WPF SVL 0.3 (Source, Binaries, Examples, Help): Version 0.3 of WPFSVL. This includes three new controls: an equalizer, a digital clock, and a time editor.Orchard Project: Orchard 1.4: Please read our release notes for Orchard 1.4: http://docs.orchardproject.net/Documentation/Orchard-1-4-Release-NotesNetSqlAzMan - .NET SQL Authorization Manager: 3.6.0.15: 3.6.0.15 28-Feb-2012 • Fix: The communication object, System.ServiceModel.Channels.ServiceChannel, cannot be used for communication because it is in the Faulted state. Work Item 10435: http://netsqlazman.codeplex.com/workitem/10435 • Fix: Made StorageCache thread safe. Thanks to tangrl. • Fix: Members property of SqlAzManApplicationGroup is not functioning. Thanks to tangrl. Work Item 10267: http://netsqlazman.codeplex.com/workitem/10267 • Fix: Indexer are making database calls. Thanks to t...SCCM Client Actions Tool: Client Actions Tool v1.1: SCCM Client Actions Tool v1.1 is the latest version. It comes with following changes since last version: Added stop button to stop the ongoing process. Added action "Query update status". Added option "saveOnlineComputers" in config.ini to enable saving list of online computers from last session. Default value for "LatestClientVersion" set to SP2 R3 (4.00.6487.2157). Wuauserv service manual startup mode is considered healthy on Windows 7. Errors are now suppressed in checkReleases...New ProjectsAbsolute Risk Game: Risk Game is a classic "World Domination Risk" game where you try to conquer the world.Architecture Document Catalog: The Architecture Document Catalog is a catalog for various documentation used by software solution architects. The initial architecture framework supported is from Rozanski and Woods, also called Viewpoints and Perspectives. It's in C#, Silverlight, WCF RIA Services.Background Worker Job Execution & Job Scheduler: Background worker is a multi-threaded job execution and scheduling engine. Very similar to Quartz, but with a slightly different focus.BWOS: preparing a new operating system. and name BWOS. CommonLibrary: Common modules and componentesCustomizeTool: CustomizeToolData Foundry: Data Foundry is a Swiss army knife for database administrator. With capabilities to cross reference check data between tables to find orphaned data and table relations.Data Grid Extensions: Modular extensions for the DataGrid control. Attach filtering capabilities to your existing DataGrid.dk.Helper: dk.Helper makes it easier for tribal wars game players (divoke-kmene.sk) to manage common activities in game. It's developed in C#.ExEn: ExEn is a high-performance implementation of a subset of the XNA API that runs on Silverlight, iOS and Android.Extended Methods for .NET: Developed in VB.NET, this DLL includes some functions I came across over the internet. Originally they were functions. I made some changes to suit my work and recreated them as Extended methods. Currently includes two extended methods for the Image class and one extended method for the String class. I will update it with new methods as I go along.GestionarComenzi: Gestioneaza Comenzi - Firma transporturiGIS Library Management: GIS Library Management System.iFinity Cache Master for DotNetNuke: The iFinity DotNetNuke Cache Master is an Administration module for DotNetNuke. This module allows administrators to inspect the current contents of the ASP.NET Cache in their running DotNetNuke installation. A very useful tool for developers working with the DotNetNuke cache.intelliEssay Document Format Checker: This is a product that tries to check a document's format to see if it conforms to certain given standard.Just T[he]IP: "Just The IP" leverages the Bing API v2 and the ip: Bing Advanced Operator to list the other web sites hosted at this IP Address (that are indexed by Bing).KTool: Ktool is a tool for learning japanese kanji. This program is still in developed. Current version can only display and find a kanji word (Press ctrl-F on main screen for search). Developed in WPF, .NET 4.0Lab Checker: Lab Checker makes it easy for teacher to check students' programs. It allows a student to test his program on a set of test cases which eliminates the need to run the program manually.MeoBox Vera Control Plugin: This is my project for creating a plugin to control my MeoBox ( Scientific Atlanta ) using Vera ( www.micasaverde.com ) Should work with other TV2Client boxesNUnitTestHelper: NUnitTestHelper is a helper class for developing unit tests for C# applications with NUnit framework. This helper library provides set of classes and method which can be used for accomplishing faster unit test development for any kind of project. NUnitTestBase – Supports basic functionality for writing a unit test with NUnit framework. This base class provides built in support for mocking framework. This version provides support for Rhino mocking framework.OnlineExam: Common online examination system based on Asp.net MVC3 can used for knowledge test, I/Q test, college test or most other test project.Orchard Code Generation Extensions: Code Generation Extensions module for Orchard.OrchardTranstion_CN: Orchar?? OsAvatar: to next step showOwnTools: About my toolsPhone Finder App: PhoneFinder will be a Windows Phone platform app alternative for finding a lost or stolen phone. Our plan is to have additional functionality the Windows software does not include. It will be developed using ASP.NET MVC, SQL Server, C#, etc.PoshChat: PoshChat is a client/server chat program written in PowerShell. Supports multiple client connections to a single server to chat.Process Attachment And Secure Text: ProcessAttachmentAndSecureText is an Exchange Transport Agent DLL and associated ASPX page. It is used to 1) strip out attachments and send them to an upload portal, and 2) to strip out text from emails and send it to an upload portal. It is currently coded for Exchange 2010Resource Viewer - Visual Studio Extension: Simply put the “resource viewer extension” enables you to visually view your ResourceDictionary. To open it go to: View – Other Windows – Resource Viewer. When working with WPF/Silverlight you put your reusable resources in a common ResourceDictionary, those resources might be of type Style, SolidColorBrush, DrawingBrush, BitmapImage and more. The problems starts when you have that ResourceDictionary you have no way to see how your resources look like, making the work process (of both t...Scumm XNA: Scumm XNA is an engine that runs old school LucasArts graphical adventure games. It is written completely in C# and will run on PC, Xbox 360 and Windows phone. The code is inspired by ScummVM but this project is not a port, it is a complete rewrite in order to optimize the engine for the CLR. Of course, you will need to own the orinigal games in order to use it. Currently, I will focus my work on the great "Day of Tentacle" game specifically the CD version.SDX DataGrid: SDXDataGrid is a comprehensive data grid component for Microsoft .NET 3.5 web application developers. It is designed to ease the exhausting process of implementing the necessary code for sorting, navigation, grouping, searching and data editing in a data representation object.SQL Scriptz Runner: Features are : Drag And Drop script files Run a directory of script files Sql Script out put messages during execution Script passed or failed that are colored green and red (yellow for running) Stop on error option Open script on error option Run report with time taken for each uComponents Demo: A demo for the code of running uComponents in Umbraco siteUnixTable: UnixTable makes it easier to realize application to access database, with no code but only with visual instrument at runtime. You'll no longer have to write query or code to read table from database. It's developed in Visual Basic for .NET 4. VOA Player.NET: VOA Player is a lightweight windows client for listening VOA Special English. Because of GFW blocking it fetch RSS data via rss2proxy.appspot.com indirectly. User can view article page and listen MP3 stream. The project is a C# implementation of voaplayer.sinaapp.com.Windows Metafile Library: The library supports reading and writing WMF files. Source code is written in pure .NET from scratch following the Windows Metafile Format Specification.Windows Phone 7.1 + MicroFramework (a phone device as remote control): Windows Phone 7.1 + .Net MicroFramework (How use a windows phone device as remote control of a Fez Panda II/MicroFramework board). A windows phone device can be connected to a wifi network (for example a wifi router). If you have also a MicroFramework board connected to the wifi network; you can send some http rest commands from the windows phone device to the MicroFramework board. The microframework board, it must support the tcp/ip protocol through a connect shield. In this exaple it will...XBMC Cache Manager: A Windows Service to manage a shared XBMC MySQL database and shared cache folder.

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  • Install Control Center Agent on Oracle Application Server

    - by qianqian.wu
    Control Center Agent (CCA) The Control Center Agent is the OWB component that runs the Template Mappings in the Oracle Containers for J2EE (OC4J) server; also referred to as the J2EE Runtime. The Control Center Agent provides a Java-based runtime environment that can be installed on Oracle and non-Oracle database hosts. The Control Center Agent provides fundamental infrastructure for the heterogeneous, Code Template-based mapping support and Web services-related features of OWB in this release. In Oracle Warehouse Builder 11gR2 the Control Center Agent, by default will run in the built-in OC4J that is bundled in the Oracle Home. Besides that, you also have ability to install the Control Center Agent in an Oracle Application Server install. In this article, you will find step-by-step instructions how to install the Control Center Agent on an Oracle Application Server instance. The instructions cover the following tasks: Task 1: Install and Configure the Application Server Task 2: Deploy the Control Center Agent to the Application Server Task 3: Optional Configuration Tasks   Task 1: Install and Configure the Application Server Before configuring the Application Server, you need to install it from Oracle Application Server CD-ROM, or by downloading the installation program from Oracle Technology Network (OTN). Once the installation is completed, you are ready to configure the Application Server. The purpose of the configuration task is to make sure the Control Center Agent ear file can be deployed and runs in the Application Server successfully. The essential configuration tasks are outlined below: · Modify the OC4J Startup Script · Set up Control Center Agent Server Side Logging · Set up Audit Table Data Source · Copy ct_permissions.properties File · Set up Security Roles for Control Center Agent · Create JMS Queues · Install JDBC Drivers to OC4J Modify the OC4J Startup Script The OC4J startup script “opmn.xml” is located in Application Server configuration directory, $AS_HOME/opmn/conf. $AS_HOME stands for the root home directory of the application server. Open the file opmn.xml in a text editor, and alter the contents of the file as displayed in the following sample. You need to make sure that: The MaxPerSize is set to 128M. This is to ensure that you allocate enough PermGen space to OC4J to run Control Center Agent. This will prevent java.lang.OutOfMemoryError when running the agent. The Python.path sets the path for the Python library files used by the Control Center Agent: jython_lib.zip and jython_owblib.jar. These two files are in the $OWB_HOME/owb/lib/int directory, where $OWB_HOME is the directory where owb is installed. · The km_security_needed determines whether restrictions will be applied to the kinds of operating system commands allowed to be executed by the OWB Code Template script executed by Control Center Agent. Setting km_security_needed to “true” enforces such restriction while setting it to “false” removes such restrictions. Set up Control Center Agent Server Side Logging Ensure that you are in the Application Server configuration directory, $AS_HOME/j2ee/home/config. Open the file j2ee-logging.xml in a text editor and add the following lines to the log handler section. The jrt-internal-log-handler is the handler used by Control Center Agent runtime logger to create log files. Then add the following entry into the loggers section to create the logger for Control Center Agent runtime auditing. Set up Audit Table Data Source To enable Audit Table logging, a managed data source and connection pool need to be set up before Control Center Agent deployment. Ensure that you are in the Application Server configuration directory, $AS_HOME/j2ee/home/config. Open the file data-sources.xml in a text editor. Define the audit data source shown below in the file, <managed-data-source name="AuditDS" connection-pool-name="OWBSYS Audit   Connection Pool" jndi-name="jdbc/AuditDS"/> <connection-pool name="OWBSYS Audit Connection Pool">   <connection-factory factory-class="oracle.jdbc.pool.OracleDataSource"     user="owbsys_audit" password="owbsys_audit"     url="jdbc:oracle:thin:@//localhost:1521/ORCL"/> </connection-pool> Copy ct_permissions.properties File The ct_permissions.properties can be obtained from $OWB_HOME /owb/jrt/config/ directory. You need to copy the file to $AS_HOME/j2ee/home/config directory.This properties file takes effect when the setting km-security is set to true in Control Center Agent. By default the ALLOWED_CMD is commented out in ct_permissions.properties file. This prevents all system command from being invoked from scripts executed in Control Center Agent (when km-security is set to true). To allow certain system commands to be invoked, ALLOWED_CMD needs to be uncommented out, and the system commands (allowed to be invoked) need to be added to the ALLOWED_CMD. Set up Security Roles for Control Center Agent You can set up the Control Center Agent security roles through Oracle Enterprise Manager. In a web browser, navigate to Enterprise Manager Homepage (e.g. http://hostname:8889/em). 1. Log in using the oc4jadmin credentials. After the Cluster Topology page is loaded, click home (the OC4J instance). This takes you to the home page of the OC4J instance. On the OC4J home screen, click the Administration tab. On the Administration Tasks screen, expand Security. Click the task icon next to Security Providers. 2. On Security Providers page click on the button “Instance Level Security”. On Instance Level Security page, go to “Realms” tab. You will see a row for the default realm “jazn.com” in the results table. It has a “Roles” column and a “Users” column. Click on the number in “Roles” column. In the “Roles” page it will display all the roles available for the realm. Click on “Create” button to create a new role “OWB_J2EE_ EXECUTOR”. 3. On the Add Role screen, enter Name OWB_J2EE_EXECUTOR, and click OK. 4. Follow the same steps as before, and create a new role “OWB_J2EE_OPERATOR”. 5. Assign role “oc4j-administrators” and “OWB_J2EE_EXECUTOR” to the role “OWB_J2EE_OPERATOR” by moving these roles from “Available Roles” and click “OK” to save. 6. Go back to Instance Level Security page and create a new role “OWB_J2EE_ADMINISTRATOR”. 7. Assign roles “OWB_J2EE_ OPERATOR” and “OWB_J2EE_EXECUTOR” to the role “OWB_J2EE_ ADMINISTRATOR” by moving these roles from “Available Roles” and click “OK” to save. 8.Go back to Instance Level Security page. This time, click on the number in “Users” column for the realm “jazn.com”. In the “Users” page, it shows all the users defined for this realm. Locate the user “oc4jadmin” in the results table and click on it. 9. Assign the roles “OWB_J2EE_ADMINISTRATOR” and “oc4j-app-administrators” to this user by moving the role from the “Available Roles” selection box to “Selected Roles” box and click “Apply” to save. 10. Go back to Instance Level Security page and create a new role “OWB_INTERNAL_USERS”, assign no user or role to this role. Simply click “OK” to create this role. Now you have finished creating the security roles required for Control Center Agent. Create JMS Queues You need to create two JMS queues for Control Center Agent: owbQueue and abort_owbQueue. 1. Now go to OC4J home Page. On the OC4J home screen, click the Administration tab. On the Administration Tasks screen, expand Services and then expand Enterprise Messaging Service. Click the task icon next to JMS Destinations. 2. On JMS Destinations page, click “Create New” button to create a new JMS queue. On Add Destination page, choose “Queue” as Destination Type. Put “owbQueue” as Destination Name. Select “In Memory Persistence Only” as the Persistence Type and put “jms/owbQueue” as JNDI Location and click on “OK” to finish. 3. Follow the same instruction as above to create the owb_abortQueue. Now you have finished creating the JMS queues required for Control Center Agent. Install JDBC Drivers to OC4J In order to execute Code Templates using commercial databases other than Oracle, e.g. DB2, SQL Server etc, the corresponding jdbc driver files need to be added to $AS_HOME/j2ee/home/applib directory. 1. To install other JDBC drivers to OC4J, first obtain the .jar file containing the JDBC driver. All the external JDBC drivers .jar files can be found in the directory: $OWB_HOME/owb/lib/ext/. For DB2, the files needed are db2jcc.jar and db2jcc_license_cu.jar. For SQL Server the file is sqljdbc.jar. For sunopsis JDBC drivers, the file needed is snpsxmlo.jar. 2. Copy the required JDBC driver file into the directory $AS_HOME/j2ee/home/applib. Now you have finished the Application Server configuration. To make the configuration to take an effect, you need to restart the Application Server.   Task 2: Deploy the Control Center Agent to the Application Server Now you can deploy the Control Center Agent to the Application Server. In a web browser, navigate to Enterprise Manager Homepage (e.g. http://hostname:8889/em). 1. Log in using the oc4jadmin credentials. After the Cluster Topology page is loaded, click home (the OC4J instance). This takes you to the home page of the OC4J instance. On the OC4J home screen, click the Applications tab. Click Deploy to begin deploying Control Center Agent. 2. On the Deploy: Select Archive screen, under Archive, select Archive is present on local host. Upload the archive to the server where Application Server Control is running. Click Browse and locate the jrt.ear file in the $OWB_HOME/owb/jrt/applications directory. Under Deployment Plan, select Automatically create a new deployment plan. Click Next. 3. Wait for the ear file to be uploaded to Application Server. On the Deploy: Application Attributes screen, enter Application Name jrt, and Context Root jrt. Leave the other attributes at their default values. Click Next. 4. On Deploy: Deployment Settings screen, leave all attributes at their default values, and click Deploy. This will take about 1 minute or so and when the application is deployed successfully, a confirmation message will be displayed. Now the Control Center Agent is started automatically. Go back to OC4J home page and click on Applications tab to make sure the deployed application jrt is showing in the applications list.   Task 3: Optional Configuration Tasks The optional configuration tasks contain: · Secure Control Center Agent Web Service · Setting the PATH Environment Variable Secure Control Center Agent Web Service If you want to use JRTWebService with a secure website, you need to do the following steps, 1. Create a file “secure-web-site.xml” in the $AS_HOME/j2ee/home/config directory. The file can be obtained from $OWB_HOME/owb/jrt/config directory. A sample secure-web-site.xml is shown as below. We need to modify the “protocol” to “https”, and “secure” to “true”, also choose an port as the secure http port. Also we need to add the entry “ssl-config” in the file. Remember to use the absolute path for the key store file. 2. Modify the file “server.xml” that is located at $AS_HOME/j2ee/home/config directory. Then add the <web-site> element in the file for the secure-web-site. 3. Create a key store file “serverkeystore.jks” in the $AS_HOME/j2ee/home/config directory. The file can be obtained from $OWB_HOME/owb/jrt/config directory. After the three files are altered, restart the application server. Now you can access the JRTWebService in SSL way through https://hostname:4443/jrt/webservice. Setting the PATH Environment Variable Sometimes, some system commands such as linux ls, sh etc, can not be executed successfully during the script execution due to they are not found in PATH. To ensure they work normally, you can setup the environment variable PATH. Let’s navigate to the Enterprise Manager Homepage. 1. Go to OC4J home screen and click the Administration tab. Expand Administration Tasks, then expand Properties. Click the task icon next to Server Properties. 2. On the Server Properties screen, scroll down to Environment Variables section. Under Environment Variables, click Add Another Row. Enter PATH in Name, and fill Value with directories that contain the system commands. Click Apply.   After you work through this article, I believe you have developed a deeper understanding of the Control Center Agent installation process, and you can apply this knowledge in other installation plan such as Control Center Agent installation on Standalone OC4J.

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  • Metro: Understanding CSS Media Queries

    - by Stephen.Walther
    If you are building a Metro style application then your application needs to look great when used on a wide variety of devices. Your application needs to work on tiny little phones, slates, desktop monitors, and the super high resolution displays of the future. Your application also must support portable devices used with different orientations. If someone tilts their phone from portrait to landscape mode then your application must still be usable. Finally, your Metro style application must look great in different states. For example, your Metro application can be in a “snapped state” when it is shrunk so it can share screen real estate with another application. In this blog post, you learn how to use Cascading Style Sheet media queries to support different devices, different device orientations, and different application states. First, you are provided with an overview of the W3C Media Query recommendation and you learn how to detect standard media features. Next, you learn about the Microsoft extensions to media queries which are supported in Metro style applications. For example, you learn how to use the –ms-view-state feature to detect whether an application is in a “snapped state” or “fill state”. Finally, you learn how to programmatically detect the features of a device and the state of an application. You learn how to use the msMatchMedia() method to execute a media query with JavaScript. Using CSS Media Queries Media queries enable you to apply different styles depending on the features of a device. Media queries are not only supported by Metro style applications, most modern web browsers now support media queries including Google Chrome 4+, Mozilla Firefox 3.5+, Apple Safari 4+, and Microsoft Internet Explorer 9+. Loading Different Style Sheets with Media Queries Imagine, for example, that you want to display different content depending on the horizontal resolution of a device. In that case, you can load different style sheets optimized for different sized devices. Consider the following HTML page: <!DOCTYPE html> <html xmlns="http://www.w3.org/1999/xhtml"> <head> <title>U.S. Robotics and Mechanical Men</title> <link href="main.css" rel="stylesheet" type="text/css" /> <!-- Less than 1100px --> <link href="medium.css" rel="stylesheet" type="text/css" media="(max-width:1100px)" /> <!-- Less than 800px --> <link href="small.css" rel="stylesheet" type="text/css" media="(max-width:800px)" /> </head> <body> <div id="header"> <h1>U.S. Robotics and Mechanical Men</h1> </div> <!-- Advertisement Column --> <div id="leftColumn"> <img src="advertisement1.gif" alt="advertisement" /> <img src="advertisement2.jpg" alt="advertisement" /> </div> <!-- Product Search Form --> <div id="mainContentColumn"> <label>Search Products</label> <input id="search" /><button>Search</button> </div> <!-- Deal of the Day Column --> <div id="rightColumn"> <h1>Deal of the Day!</h1> <p> Buy two cameras and get a third camera for free! Offer is good for today only. </p> </div> </body> </html> The HTML page above contains three columns: a leftColumn, mainContentColumn, and rightColumn. When the page is displayed on a low resolution device, such as a phone, only the mainContentColumn appears: When the page is displayed in a medium resolution device, such as a slate, both the leftColumn and the mainContentColumns are displayed: Finally, when the page is displayed in a high-resolution device, such as a computer monitor, all three columns are displayed: Different content is displayed with the help of media queries. The page above contains three style sheet links. Two of the style links include a media attribute: <link href="main.css" rel="stylesheet" type="text/css" /> <!-- Less than 1100px --> <link href="medium.css" rel="stylesheet" type="text/css" media="(max-width:1100px)" /> <!-- Less than 800px --> <link href="small.css" rel="stylesheet" type="text/css" media="(max-width:800px)" /> The main.css style sheet contains default styles for the elements in the page. The medium.css style sheet is applied when the page width is less than 1100px. This style sheet hides the rightColumn and changes the page background color to lime: html { background-color: lime; } #rightColumn { display:none; } Finally, the small.css style sheet is loaded when the page width is less than 800px. This style sheet hides the leftColumn and changes the page background color to red: html { background-color: red; } #leftColumn { display:none; } The different style sheets are applied as you stretch and contract your browser window. You don’t need to refresh the page after changing the size of the page for a media query to be applied: Using the @media Rule You don’t need to divide your styles into separate files to take advantage of media queries. You can group styles by using the @media rule. For example, the following HTML page contains one set of styles which are applied when a device’s orientation is portrait and another set of styles when a device’s orientation is landscape: <!DOCTYPE html> <html> <head> <meta charset="utf-8" /> <title>Application1</title> <style type="text/css"> html { font-family:'Segoe UI Semilight'; font-size: xx-large; } @media screen and (orientation:landscape) { html { background-color: lime; } p.content { width: 50%; margin: auto; } } @media screen and (orientation:portrait) { html { background-color: red; } p.content { width: 90%; margin: auto; } } </style> </head> <body> <p class="content"> Lorem ipsum dolor sit amet, consectetuer adipiscing elit. Maecenas porttitor congue massa. Fusce posuere, magna sed pulvinar ultricies, purus lectus malesuada libero, sit amet commodo magna eros quis urna. </p> </body> </html> When a device has a landscape orientation then the background color is set to the color lime and the text only takes up 50% of the available horizontal space: When the device has a portrait orientation then the background color is red and the text takes up 90% of the available horizontal space: Using Standard CSS Media Features The official list of standard media features is contained in the W3C CSS Media Query recommendation located here: http://www.w3.org/TR/css3-mediaqueries/ Here is the official list of the 13 media features described in the standard: · width – The current width of the viewport · height – The current height of the viewport · device-width – The width of the device · device-height – The height of the device · orientation – The value portrait or landscape · aspect-ratio – The ratio of width to height · device-aspect-ratio – The ratio of device width to device height · color – The number of bits per color supported by the device · color-index – The number of colors in the color lookup table of the device · monochrome – The number of bits in the monochrome frame buffer · resolution – The density of the pixels supported by the device · scan – The values progressive or interlace (used for TVs) · grid – The values 0 or 1 which indicate whether the device supports a grid or a bitmap Many of the media features in the list above support the min- and max- prefix. For example, you can test for the min-width using a query like this: (min-width:800px) You can use the logical and operator with media queries when you need to check whether a device supports more than one feature. For example, the following query returns true only when the width of the device is between 800 and 1,200 pixels: (min-width:800px) and (max-width:1200px) Finally, you can use the different media types – all, braille, embossed, handheld, print, projection, screen, speech, tty, tv — with a media query. For example, the following media query only applies to a page when a page is being printed in color: print and (color) If you don’t specify a media type then media type all is assumed. Using Metro Style Media Features Microsoft has extended the standard list of media features which you can include in a media query with two custom media features: · -ms-high-contrast – The values any, black-white, white-black · -ms-view-state – The values full-screen, fill, snapped, device-portrait You can take advantage of the –ms-high-contrast media feature to make your web application more accessible to individuals with disabilities. In high contrast mode, you should make your application easier to use for individuals with vision disabilities. The –ms-view-state media feature enables you to detect the state of an application. For example, when an application is snapped, the application only occupies part of the available screen real estate. The snapped application appears on the left or right side of the screen and the rest of the screen real estate is dominated by the fill application (Metro style applications can only be snapped on devices with a horizontal resolution of greater than 1,366 pixels). Here is a page which contains style rules for an application in both a snap and fill application state: <!DOCTYPE html> <html> <head> <meta charset="utf-8" /> <title>MyWinWebApp</title> <style type="text/css"> html { font-family:'Segoe UI Semilight'; font-size: xx-large; } @media screen and (-ms-view-state:snapped) { html { background-color: lime; } } @media screen and (-ms-view-state:fill) { html { background-color: red; } } </style> </head> <body> <p class="content"> Lorem ipsum dolor sit amet, consectetuer adipiscing elit. Maecenas porttitor congue massa. Fusce posuere, magna sed pulvinar ultricies, purus lectus malesuada libero, sit amet commodo magna eros quis urna. </p> </body> </html> When the application is snapped, the application appears with a lime background color: When the application state is fill then the background color changes to red: When the application takes up the entire screen real estate – it is not in snapped or fill state – then no special style rules apply and the application appears with a white background color. Querying Media Features with JavaScript You can perform media queries using JavaScript by taking advantage of the window.msMatchMedia() method. This method returns a MSMediaQueryList which has a matches method that represents success or failure. For example, the following code checks whether the current device is in portrait mode: if (window.msMatchMedia("(orientation:portrait)").matches) { console.log("portrait"); } else { console.log("landscape"); } If the matches property returns true, then the device is in portrait mode and the message “portrait” is written to the Visual Studio JavaScript Console window. Otherwise, the message “landscape” is written to the JavaScript Console window. You can create an event listener which triggers code whenever the results of a media query changes. For example, the following code writes a message to the JavaScript Console whenever the current device is switched into or out of Portrait mode: window.msMatchMedia("(orientation:portrait)").addListener(function (mql) { if (mql.matches) { console.log("Switched to portrait"); } }); Be aware that the event listener is triggered whenever the result of the media query changes. So the event listener is triggered both when you switch from landscape to portrait and when you switch from portrait to landscape. For this reason, you need to verify that the matches property has the value true before writing the message. Summary The goal of this blog entry was to explain how CSS media queries work in the context of a Metro style application written with JavaScript. First, you were provided with an overview of the W3C CSS Media Query recommendation. You learned about the standard media features which you can query such as width and orientation. Next, we focused on the Microsoft extensions to media queries. You learned how to use –ms-view-state to detect whether a Metro style application is in “snapped” or “fill” state. You also learned how to use the msMatchMedia() method to perform a media query from JavaScript.

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  • How to Run Low-Cost Minecraft on a Raspberry Pi for Block Building on the Cheap

    - by Jason Fitzpatrick
    We’ve shown you how to run your own blocktastic personal Minecraft server on a Windows/OSX box, but what if you crave something lighter weight, more energy efficient, and always ready for your friends? Read on as we turn a tiny Raspberry Pi machine into a low-cost Minecraft server you can leave on 24/7 for around a penny a day. Why Do I Want to Do This? There’s two aspects to this tutorial, running your own Minecraft server and specifically running that Minecraft server on a Raspberry Pi. Why would you want to run your own Minecraft server? It’s a really great way to extend and build upon the Minecraft play experience. You can leave the server running when you’re not playing so friends and family can join and continue building your world. You can mess around with game variables and introduce mods in a way that isn’t possible when you’re playing the stand-alone game. It also gives you the kind of control over your multiplayer experience that using public servers doesn’t, without incurring the cost of hosting a private server on a remote host. While running a Minecraft server on its own is appealing enough to a dedicated Minecraft fan, running it on the Raspberry Pi is even more appealing. The tiny little Pi uses so little resources that you can leave your Minecraft server running 24/7 for a couple bucks a year. Aside from the initial cost outlay of the Pi, an SD card, and a little bit of time setting it up, you’ll have an always-on Minecraft server at a monthly cost of around one gumball. What Do I Need? For this tutorial you’ll need a mix of hardware and software tools; aside from the actual Raspberry Pi and SD card, everything is free. 1 Raspberry Pi (preferably a 512MB model) 1 4GB+ SD card This tutorial assumes that you have already familiarized yourself with the Raspberry Pi and have installed a copy of the Debian-derivative Raspbian on the device. If you have not got your Pi up and running yet, don’t worry! Check out our guide, The HTG Guide to Getting Started with Raspberry Pi, to get up to speed. Optimizing Raspbian for the Minecraft Server Unlike other builds we’ve shared where you can layer multiple projects over one another (e.g. the Pi is more than powerful enough to serve as a weather/email indicator and a Google Cloud Print server at the same time) running a Minecraft server is a pretty intense operation for the little Pi and we’d strongly recommend dedicating the entire Pi to the process. Minecraft seems like a simple game, with all its blocky-ness and what not, but it’s actually a pretty complex game beneath the simple skin and required a lot of processing power. As such, we’re going to tweak the configuration file and other settings to optimize Rasbian for the job. The first thing you’ll need to do is dig into the Raspi-Config application to make a few minor changes. If you’re installing Raspbian fresh, wait for the last step (which is the Raspi-Config), if you already installed it, head to the terminal and type in “sudo raspi-config” to launch it again. One of the first and most important things we need to attend to is cranking up the overclock setting. We need all the power we can get to make our Minecraft experience enjoyable. In Raspi-Config, select option number 7 “Overclock”. Be prepared for some stern warnings about overclocking, but rest easy knowing that overclocking is directly supported by the Raspberry Pi foundation and has been included in the configuration options since late 2012. Once you’re in the actual selection screen, select “Turbo 1000MhHz”. Again, you’ll be warned that the degree of overclocking you’ve selected carries risks (specifically, potential corruption of the SD card, but no risk of actual hardware damage). Click OK and wait for the device to reset. Next, make sure you’re set to boot to the command prompt, not the desktop. Select number 3 “Enable Boot to Desktop/Scratch”  and make sure “Console Text console” is selected. Back at the Raspi-Config menu, select number 8 “Advanced Options’. There are two critical changes we need to make in here and one option change. First, the critical changes. Select A3 “Memory Split”: Change the amount of memory available to the GPU to 16MB (down from the default 64MB). Our Minecraft server is going to ruin in a GUI-less environment; there’s no reason to allocate any more than the bare minimum to the GPU. After selecting the GPU memory, you’ll be returned to the main menu. Select “Advanced Options” again and then select A4 “SSH”. Within the sub-menu, enable SSH. There is very little reason to keep this Pi connected to a monitor and keyboard, by enabling SSH we can remotely access the machine from anywhere on the network. Finally (and optionally) return again to the “Advanced Options” menu and select A2 “Hostname”. Here you can change your hostname from “raspberrypi” to a more fitting Minecraft name. We opted for the highly creative hostname “minecraft”, but feel free to spice it up a bit with whatever you feel like: creepertown, minecraft4life, or miner-box are all great minecraft server names. That’s it for the Raspbian configuration tab down to the bottom of the main screen and select “Finish” to reboot. After rebooting you can now SSH into your terminal, or continue working from the keyboard hooked up to your Pi (we strongly recommend switching over to SSH as it allows you to easily cut and paste the commands). If you’ve never used SSH before, check out how to use PuTTY with your Pi here. Installing Java on the Pi The Minecraft server runs on Java, so the first thing we need to do on our freshly configured Pi is install it. Log into your Pi via SSH and then, at the command prompt, enter the following command to make a directory for the installation: sudo mkdir /java/ Now we need to download the newest version of Java. At the time of this publication the newest release is the OCT 2013 update and the link/filename we use will reflect that. Please check for a more current version of the Linux ARMv6/7 Java release on the Java download page and update the link/filename accordingly when following our instructions. At the command prompt, enter the following command: sudo wget --no-check-certificate http://www.java.net/download/jdk8/archive/b111/binaries/jdk-8-ea-b111-linux-arm-vfp-hflt-09_oct_2013.tar.gz Once the download has finished successfully, enter the following command: sudo tar zxvf jdk-8-ea-b111-linux-arm-vfp-hflt-09_oct_2013.tar.gz -C /opt/ Fun fact: the /opt/ directory name scheme is a remnant of early Unix design wherein the /opt/ directory was for “optional” software installed after the main operating system; it was the /Program Files/ of the Unix world. After the file has finished extracting, enter: sudo /opt/jdk1.8.0/bin/java -version This command will return the version number of your new Java installation like so: java version "1.8.0-ea" Java(TM) SE Runtime Environment (build 1.8.0-ea-b111) Java HotSpot(TM) Client VM (build 25.0-b53, mixed mode) If you don’t see the above printout (or a variation thereof if you’re using a newer version of Java), try to extract the archive again. If you do see the readout, enter the following command to tidy up after yourself: sudo rm jdk-8-ea-b111-linux-arm-vfp-hflt-09_oct_2013.tar.gz At this point Java is installed and we’re ready to move onto installing our Minecraft server! Installing and Configuring the Minecraft Server Now that we have a foundation for our Minecraft server, it’s time to install the part that matter. We’ll be using SpigotMC a lightweight and stable Minecraft server build that works wonderfully on the Pi. First, grab a copy of the the code with the following command: sudo wget http://ci.md-5.net/job/Spigot/lastSuccessfulBuild/artifact/Spigot-Server/target/spigot.jar This link should remain stable over time, as it points directly to the most current stable release of Spigot, but if you have any issues you can always reference the SpigotMC download page here. After the download finishes successfully, enter the following command: sudo /opt/jdk1.8.0/bin/java -Xms256M -Xmx496M -jar /home/pi/spigot.jar nogui Note: if you’re running the command on a 256MB Pi change the 256 and 496 in the above command to 128 and 256, respectively. Your server will launch and a flurry of on-screen activity will follow. Be prepared to wait around 3-6 minutes or so for the process of setting up the server and generating the map to finish. Future startups will take much less time, around 20-30 seconds. Note: If at any point during the configuration or play process things get really weird (e.g. your new Minecraft server freaks out and starts spawning you in the Nether and killing you instantly), use the “stop” command at the command prompt to gracefully shutdown the server and let you restart and troubleshoot it. After the process has finished, head over to the computer you normally play Minecraft on, fire it up, and click on Multiplayer. You should see your server: If your world doesn’t popup immediately during the network scan, hit the Add button and manually enter the address of your Pi. Once you connect to the server, you’ll see the status change in the server status window: According to the server, we’re in game. According to the actual Minecraft app, we’re also in game but it’s the middle of the night in survival mode: Boo! Spawning in the dead of night, weaponless and without shelter is no way to start things. No worries though, we need to do some more configuration; no time to sit around and get shot at by skeletons. Besides, if you try and play it without some configuration tweaks first, you’ll likely find it quite unstable. We’re just here to confirm the server is up, running, and accepting incoming connections. Once we’ve confirmed the server is running and connectable (albeit not very playable yet), it’s time to shut down the server. Via the server console, enter the command “stop” to shut everything down. When you’re returned to the command prompt, enter the following command: sudo nano server.properties When the configuration file opens up, make the following changes (or just cut and paste our config file minus the first two lines with the name and date stamp): #Minecraft server properties #Thu Oct 17 22:53:51 UTC 2013 generator-settings= #Default is true, toggle to false allow-nether=false level-name=world enable-query=false allow-flight=false server-port=25565 level-type=DEFAULT enable-rcon=false force-gamemode=false level-seed= server-ip= max-build-height=256 spawn-npcs=true white-list=false spawn-animals=true texture-pack= snooper-enabled=true hardcore=false online-mode=true pvp=true difficulty=1 player-idle-timeout=0 gamemode=0 #Default 20; you only need to lower this if you're running #a public server and worried about loads. max-players=20 spawn-monsters=true #Default is 10, 3-5 ideal for Pi view-distance=5 generate-structures=true spawn-protection=16 motd=A Minecraft Server In the server status window, seen through your SSH connection to the pi, enter the following command to give yourself operator status on your Minecraft server (so that you can use more powerful commands in game, without always returning to the server status window). op [your minecraft nickname] At this point things are looking better but we still have a little tweaking to do before the server is really enjoyable. To that end, let’s install some plugins. The first plugin, and the one you should install above all others, is NoSpawnChunks. To install the plugin, first visit the NoSpawnChunks webpage and grab the download link for the most current version. As of this writing the current release is v0.3. Back at the command prompt (the command prompt of your Pi, not the server console–if your server is still active shut it down) enter the following commands: cd /home/pi/plugins sudo wget http://dev.bukkit.org/media/files/586/974/NoSpawnChunks.jar Next, visit the ClearLag plugin page, and grab the latest link (as of this tutorial, it’s v2.6.0). Enter the following at the command prompt: sudo wget http://dev.bukkit.org/media/files/743/213/Clearlag.jar Because the files aren’t compressed in a .ZIP or similar container, that’s all there is to it: the plugins are parked in the plugin directory. (Remember this for future plugin downloads, the file needs to be whateverplugin.jar, so if it’s compressed you need to uncompress it in the plugin directory.) Resart the server: sudo /opt/jdk1.8.0/bin/java -Xms256M -Xmx496M -jar /home/pi/spigot.jar nogui Be prepared for a slightly longer startup time (closer to the 3-6 minutes and much longer than the 30 seconds you just experienced) as the plugins affect the world map and need a minute to massage everything. After the spawn process finishes, type the following at the server console: plugins This lists all the plugins currently active on the server. You should see something like this: If the plugins aren’t loaded, you may need to stop and restart the server. After confirming your plugins are loaded, go ahead and join the game. You should notice significantly snappier play. In addition, you’ll get occasional messages from the plugins indicating they are active, as seen below: At this point Java is installed, the server is installed, and we’ve tweaked our settings for for the Pi.  It’s time to start building with friends!     

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  • MERGE Bug with Filtered Indexes

    - by Paul White
    A MERGE statement can fail, and incorrectly report a unique key violation when: The target table uses a unique filtered index; and No key column of the filtered index is updated; and A column from the filtering condition is updated; and Transient key violations are possible Example Tables Say we have two tables, one that is the target of a MERGE statement, and another that contains updates to be applied to the target.  The target table contains three columns, an integer primary key, a single character alternate key, and a status code column.  A filtered unique index exists on the alternate key, but is only enforced where the status code is ‘a’: CREATE TABLE #Target ( pk integer NOT NULL, ak character(1) NOT NULL, status_code character(1) NOT NULL,   PRIMARY KEY (pk) );   CREATE UNIQUE INDEX uq1 ON #Target (ak) INCLUDE (status_code) WHERE status_code = 'a'; The changes table contains just an integer primary key (to identify the target row to change) and the new status code: CREATE TABLE #Changes ( pk integer NOT NULL, status_code character(1) NOT NULL,   PRIMARY KEY (pk) ); Sample Data The sample data for the example is: INSERT #Target (pk, ak, status_code) VALUES (1, 'A', 'a'), (2, 'B', 'a'), (3, 'C', 'a'), (4, 'A', 'd');   INSERT #Changes (pk, status_code) VALUES (1, 'd'), (4, 'a');          Target                     Changes +-----------------------+    +------------------+ ¦ pk ¦ ak ¦ status_code ¦    ¦ pk ¦ status_code ¦ ¦----+----+-------------¦    ¦----+-------------¦ ¦  1 ¦ A  ¦ a           ¦    ¦  1 ¦ d           ¦ ¦  2 ¦ B  ¦ a           ¦    ¦  4 ¦ a           ¦ ¦  3 ¦ C  ¦ a           ¦    +------------------+ ¦  4 ¦ A  ¦ d           ¦ +-----------------------+ The target table’s alternate key (ak) column is unique, for rows where status_code = ‘a’.  Applying the changes to the target will change row 1 from status ‘a’ to status ‘d’, and row 4 from status ‘d’ to status ‘a’.  The result of applying all the changes will still satisfy the filtered unique index, because the ‘A’ in row 1 will be deleted from the index and the ‘A’ in row 4 will be added. Merge Test One Let’s now execute a MERGE statement to apply the changes: MERGE #Target AS t USING #Changes AS c ON c.pk = t.pk WHEN MATCHED AND c.status_code <> t.status_code THEN UPDATE SET status_code = c.status_code; The MERGE changes the two target rows as expected.  The updated target table now contains: +-----------------------+ ¦ pk ¦ ak ¦ status_code ¦ ¦----+----+-------------¦ ¦  1 ¦ A  ¦ d           ¦ <—changed from ‘a’ ¦  2 ¦ B  ¦ a           ¦ ¦  3 ¦ C  ¦ a           ¦ ¦  4 ¦ A  ¦ a           ¦ <—changed from ‘d’ +-----------------------+ Merge Test Two Now let’s repopulate the changes table to reverse the updates we just performed: TRUNCATE TABLE #Changes;   INSERT #Changes (pk, status_code) VALUES (1, 'a'), (4, 'd'); This will change row 1 back to status ‘a’ and row 4 back to status ‘d’.  As a reminder, the current state of the tables is:          Target                        Changes +-----------------------+    +------------------+ ¦ pk ¦ ak ¦ status_code ¦    ¦ pk ¦ status_code ¦ ¦----+----+-------------¦    ¦----+-------------¦ ¦  1 ¦ A  ¦ d           ¦    ¦  1 ¦ a           ¦ ¦  2 ¦ B  ¦ a           ¦    ¦  4 ¦ d           ¦ ¦  3 ¦ C  ¦ a           ¦    +------------------+ ¦  4 ¦ A  ¦ a           ¦ +-----------------------+ We execute the same MERGE statement: MERGE #Target AS t USING #Changes AS c ON c.pk = t.pk WHEN MATCHED AND c.status_code <> t.status_code THEN UPDATE SET status_code = c.status_code; However this time we receive the following message: Msg 2601, Level 14, State 1, Line 1 Cannot insert duplicate key row in object 'dbo.#Target' with unique index 'uq1'. The duplicate key value is (A). The statement has been terminated. Applying the changes using UPDATE Let’s now rewrite the MERGE to use UPDATE instead: UPDATE t SET status_code = c.status_code FROM #Target AS t JOIN #Changes AS c ON t.pk = c.pk WHERE c.status_code <> t.status_code; This query succeeds where the MERGE failed.  The two rows are updated as expected: +-----------------------+ ¦ pk ¦ ak ¦ status_code ¦ ¦----+----+-------------¦ ¦  1 ¦ A  ¦ a           ¦ <—changed back to ‘a’ ¦  2 ¦ B  ¦ a           ¦ ¦  3 ¦ C  ¦ a           ¦ ¦  4 ¦ A  ¦ d           ¦ <—changed back to ‘d’ +-----------------------+ What went wrong with the MERGE? In this test, the MERGE query execution happens to apply the changes in the order of the ‘pk’ column. In test one, this was not a problem: row 1 is removed from the unique filtered index by changing status_code from ‘a’ to ‘d’ before row 4 is added.  At no point does the table contain two rows where ak = ‘A’ and status_code = ‘a’. In test two, however, the first change was to change row 1 from status ‘d’ to status ‘a’.  This change means there would be two rows in the filtered unique index where ak = ‘A’ (both row 1 and row 4 meet the index filtering criteria ‘status_code = a’). The storage engine does not allow the query processor to violate a unique key (unless IGNORE_DUP_KEY is ON, but that is a different story, and doesn’t apply to MERGE in any case).  This strict rule applies regardless of the fact that if all changes were applied, there would be no unique key violation (row 4 would eventually be changed from ‘a’ to ‘d’, removing it from the filtered unique index, and resolving the key violation). Why it went wrong The query optimizer usually detects when this sort of temporary uniqueness violation could occur, and builds a plan that avoids the issue.  I wrote about this a couple of years ago in my post Beware Sneaky Reads with Unique Indexes (you can read more about the details on pages 495-497 of Microsoft SQL Server 2008 Internals or in Craig Freedman’s blog post on maintaining unique indexes).  To summarize though, the optimizer introduces Split, Filter, Sort, and Collapse operators into the query plan to: Split each row update into delete followed by an inserts Filter out rows that would not change the index (due to the filter on the index, or a non-updating update) Sort the resulting stream by index key, with deletes before inserts Collapse delete/insert pairs on the same index key back into an update The effect of all this is that only net changes are applied to an index (as one or more insert, update, and/or delete operations).  In this case, the net effect is a single update of the filtered unique index: changing the row for ak = ‘A’ from pk = 4 to pk = 1.  In case that is less than 100% clear, let’s look at the operation in test two again:          Target                     Changes                   Result +-----------------------+    +------------------+    +-----------------------+ ¦ pk ¦ ak ¦ status_code ¦    ¦ pk ¦ status_code ¦    ¦ pk ¦ ak ¦ status_code ¦ ¦----+----+-------------¦    ¦----+-------------¦    ¦----+----+-------------¦ ¦  1 ¦ A  ¦ d           ¦    ¦  1 ¦ d           ¦    ¦  1 ¦ A  ¦ a           ¦ ¦  2 ¦ B  ¦ a           ¦    ¦  4 ¦ a           ¦    ¦  2 ¦ B  ¦ a           ¦ ¦  3 ¦ C  ¦ a           ¦    +------------------+    ¦  3 ¦ C  ¦ a           ¦ ¦  4 ¦ A  ¦ a           ¦                            ¦  4 ¦ A  ¦ d           ¦ +-----------------------+                            +-----------------------+ From the filtered index’s point of view (filtered for status_code = ‘a’ and shown in nonclustered index key order) the overall effect of the query is:   Before           After +---------+    +---------+ ¦ pk ¦ ak ¦    ¦ pk ¦ ak ¦ ¦----+----¦    ¦----+----¦ ¦  4 ¦ A  ¦    ¦  1 ¦ A  ¦ ¦  2 ¦ B  ¦    ¦  2 ¦ B  ¦ ¦  3 ¦ C  ¦    ¦  3 ¦ C  ¦ +---------+    +---------+ The single net change there is a change of pk from 4 to 1 for the nonclustered index entry ak = ‘A’.  This is the magic performed by the split, sort, and collapse.  Notice in particular how the original changes to the index key (on the ‘ak’ column) have been transformed into an update of a non-key column (pk is included in the nonclustered index).  By not updating any nonclustered index keys, we are guaranteed to avoid transient key violations. The Execution Plans The estimated MERGE execution plan that produces the incorrect key-violation error looks like this (click to enlarge in a new window): The successful UPDATE execution plan is (click to enlarge in a new window): The MERGE execution plan is a narrow (per-row) update.  The single Clustered Index Merge operator maintains both the clustered index and the filtered nonclustered index.  The UPDATE plan is a wide (per-index) update.  The clustered index is maintained first, then the Split, Filter, Sort, Collapse sequence is applied before the nonclustered index is separately maintained. There is always a wide update plan for any query that modifies the database. The narrow form is a performance optimization where the number of rows is expected to be relatively small, and is not available for all operations.  One of the operations that should disallow a narrow plan is maintaining a unique index where intermediate key violations could occur. Workarounds The MERGE can be made to work (producing a wide update plan with split, sort, and collapse) by: Adding all columns referenced in the filtered index’s WHERE clause to the index key (INCLUDE is not sufficient); or Executing the query with trace flag 8790 set e.g. OPTION (QUERYTRACEON 8790). Undocumented trace flag 8790 forces a wide update plan for any data-changing query (remember that a wide update plan is always possible).  Either change will produce a successfully-executing wide update plan for the MERGE that failed previously. Conclusion The optimizer fails to spot the possibility of transient unique key violations with MERGE under the conditions listed at the start of this post.  It incorrectly chooses a narrow plan for the MERGE, which cannot provide the protection of a split/sort/collapse sequence for the nonclustered index maintenance. The MERGE plan may fail at execution time depending on the order in which rows are processed, and the distribution of data in the database.  Worse, a previously solid MERGE query may suddenly start to fail unpredictably if a filtered unique index is added to the merge target table at any point. Connect bug filed here Tests performed on SQL Server 2012 SP1 CUI (build 11.0.3321) x64 Developer Edition © 2012 Paul White – All Rights Reserved Twitter: @SQL_Kiwi Email: [email protected]

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  • CodePlex Daily Summary for Friday, January 07, 2011

    CodePlex Daily Summary for Friday, January 07, 2011Popular ReleasesAutoLoL: AutoLoL v1.5.2: Implemented the Auto Updater Fix: Your settings will no longer be cleared with new releases of AutoLoL The mastery Editor and Browser now have their own tabs instead of nested tabs The Browser tab will only show the masteries matching ALL filters instead of just one Added a 'Browse' button in the Mastery Editor tab to open the Masteries Directory The Browser tab now shows a message when there are no mastery files in the Masteries Directory Fix: Fixed the Save As dialog again, for ...Ionics Isapi Rewrite Filter: 2.1 latest stable: V2.1 is stable, and is in maintenance mode. This is v2.1.1.25. It is a bug-fix release. There are no new features. 28629 29172 28722 27626 28074 29164 27659 27900 many documentation updates and fixes proper x64 build environment. This release includes x64 binaries in zip form, but no x64 MSI file. You'll have to manually install x64 servers, following the instructions in the documentation.StyleCop for ReSharper: StyleCop for ReSharper 5.1.14980.000: A considerable amount of work has gone into this release: Huge focus on performance around the violation scanning subsystem: - caching added to reduce IO operations around reading and merging of settings files - caching added to reduce creation of expensive objects Users should notice condsiderable perf boost and a decrease in memory usage. Bug Fixes: - StyleCop's new ObjectBasedEnvironment object does not resolve the StyleCop installation path, thus it does not return the correct path ...VivoSocial: VivoSocial 7.4.1: New release with bug fixes and updates for performance.SSH.NET Library: 2011.1.6: Fixes CommandTimeout default value is fixed to infinite. Port Forwarding feature improvements Memory leaks fixes New Features Add ErrorOccurred event to handle errors that occurred on different thread New and improve SFTP features SftpFile now has more attributes and some operations Most standard operations now available Allow specify encoding for command execution KeyboardInteractiveConnectionInfo class added for "keyboard-interactive" authentication. Add ability to specify bo....NET Extensions - Extension Methods Library for C# and VB.NET: Release 2011.03: Added lot's of new extensions and new projects for MVC and Entity Framework. object.FindTypeByRecursion Int32.InRange String.RemoveAllSpecialCharacters String.IsEmptyOrWhiteSpace String.IsNotEmptyOrWhiteSpace String.IfEmptyOrWhiteSpace String.ToUpperFirstLetter String.GetBytes String.ToTitleCase String.ToPlural DateTime.GetDaysInYear DateTime.GetPeriodOfDay IEnumberable.RemoveAll IEnumberable.Distinct ICollection.RemoveAll IList.Join IList.Match IList.Cast Array.IsNullOrEmpty Array.W...VidCoder: 0.8.0: Added x64 version. Made the audio output preview more detailed and accurate. If the chosen encoder or mixdown is incompatible with the source, the fallback that will be used is displayed. Added "Auto" to the audio mixdown choices. Reworked non-anamorphic size calculation to work better with non-standard pixel aspect ratios and cropping. Reworked Custom anamorphic to be more intuitive and allow display width to be set automatically (Thanks, Statick). Allowing higher bitrates for 6-ch....NET Voice Recorder: Auto-Tune Release: This is the source code and binaries to accompany the article on the Coding 4 Fun website. It is the Auto Tuner release of the .NET Voice Recorder application.BloodSim: BloodSim - 1.3.2.0: - Simulation Log is now automatically disabled and hidden when running 10 or more iterations - Hit and Expertise are now entered by Rating, and include option for a Racial Expertise bonus - Added option for boss to use a periodic magic ability (Dragon Breath) - Added option for boss to periodically Enrage, gaining a Damage/Attack Speed buffASP.NET MVC CMS ( Using CommonLibrary.NET ): CommonLibrary.NET CMS 0.9.5 Alpha: CommonLibrary CMSA simple yet powerful CMS system in ASP.NET MVC 2 using C# 4.0. ActiveRecord based components for Blogs, Widgets, Pages, Parts, Events, Feedback, BlogRolls, Links Includes several widgets ( tag cloud, archives, recent, user cloud, links twitter, blog roll and more ) Built using the http://commonlibrarynet.codeplex.com framework. ( Uses TDD, DDD, Models/Entities, Code Generation ) Can run w/ In-Memory Repositories or Sql Server Database See Documentation tab for Ins...AllNewsManager.NET: AllNewsManager.NET 1.2.1: AllNewsManager.NET 1.2.1 It is a minor update from version 1.2EnhSim: EnhSim 2.2.9 BETA: 2.2.9 BETAThis release supports WoW patch 4.03a at level 85 To use this release, you must have the Microsoft Visual C++ 2010 Redistributable Package installed. This can be downloaded from http://www.microsoft.com/downloads/en/details.aspx?FamilyID=A7B7A05E-6DE6-4D3A-A423-37BF0912DB84 To use the GUI you must have the .NET 4.0 Framework installed. This can be downloaded from http://www.microsoft.com/downloads/en/details.aspx?FamilyID=9cfb2d51-5ff4-4491-b0e5-b386f32c0992 - Added in the Gobl...xUnit.net - Unit Testing for .NET: xUnit.net 1.7 Beta: xUnit.net release 1.7 betaBuild #1533 Important notes for Resharper users: Resharper support has been moved to the xUnit.net Contrib project. Important note for TestDriven.net users: If you are having issues running xUnit.net tests in TestDriven.net, especially on 64-bit Windows, we strongly recommend you upgrade to TD.NET version 3.0 or later. This release adds the following new features: Added support for ASP.NET MVC 3 Added Assert.Equal(double expected, double actual, int precision)...Json.NET: Json.NET 4.0 Release 1: New feature - Added Windows Phone 7 project New feature - Added dynamic support to LINQ to JSON New feature - Added dynamic support to serializer New feature - Added INotifyCollectionChanged to JContainer in .NET 4 build New feature - Added ReadAsDateTimeOffset to JsonReader New feature - Added ReadAsDecimal to JsonReader New feature - Added covariance to IJEnumerable type parameter New feature - Added XmlSerializer style Specified property support New feature - Added ...DbDocument: DbDoc Initial Version: DbDoc Initial versionASP .NET MVC CMS (Content Management System): Atomic CMS 2.1.2: Atomic CMS 2.1.2 release notes Atomic CMS installation guide N2 CMS: 2.1: N2 is a lightweight CMS framework for ASP.NET. It helps you build great web sites that anyone can update. Major Changes Support for auto-implemented properties ({get;set;}, based on contribution by And Poulsen) All-round improvements and bugfixes File manager improvements (multiple file upload, resize images to fit) New image gallery Infinite scroll paging on news Content templates First time with N2? Try the demo site Download one of the template packs (above) and open the proj...Mobile Device Detection and Redirection: 0.1.11.10: IMPORTANT CHANGESThis release changes the way some WURFL capabilities and attributes are exposed to .NET developers. If you cast MobileCapabilities to return some values then please read the Release Note before implementing this release. The following code snippet can be used to access any WURFL capability. For instance, if the device is a tablet: string capability = Request.Browser["is_tablet"]; SummaryNew attributes have been added to the redirect section: originalUrlAsQueryString If se...Wii Backup Fusion: Wii Backup Fusion 1.0: - Norwegian translation - French translation - German translation - WBFS dump for analysis - Scalable full HQ cover - Support for log file - Load game images improved - Support for image splitting - Diff for images after transfer - Support for scrubbing modes - Search functionality for log - Recurse depth for Files/Load - Show progress while downloading game cover - Supports more databases for cover download - Game cover loading routines improvedBlogEngine.NET: BlogEngine.NET 2.0: Get DotNetBlogEngine for 3 Months Free! Click Here for More Info 3 Months FREE – BlogEngine.NET Hosting – Click Here! If you want to set up and start using BlogEngine.NET right away, you should download the Web project. If you want to extend or modify BlogEngine.NET, you should download the source code. If you are upgrading from a previous version of BlogEngine.NET, please take a look at the Upgrading to BlogEngine.NET 2.0 instructions. To get started, be sure to check out our installatio...New Projects9192631770: This project is created for learning .net 3.5 personally. However it may not suffice for anyone to give a start point. (9192631770) is equivalent to 1 sec in atomic clock.AGS: AGSAll-In-One Code Framework Prerelease: All-In-One Code Framework PrereleaseAwait Events with "yield": This is a library that allows you to stop running the code wherever you want in order to await an event using the functionality of "yield" sentence. It's useful when you want to await asynchronous events or when you have to deal with many events in a sequential way.Battle.net SDK: This is a SDK that retrieves it's information from the Battle.Net community site. At the moment blizzard only supports this for World of Warcraft, so that's what our main aim is at the momeen.t C++ Hash Container Benchmark: C++ Hash Container Benchmark for STL map, C++0x unordered map, Boost unordered map, ATL map and ATL hash map for STL wide string and ATL CString.Colour Lovers .NET: A .NET library for the Colour Lovers API.DatingGame: Course to teach high-school aged girls basic T-SQL using a fun scenario - querying to find the hottest boys! Used at Microsoft DigiGirlz and TKP events. Included DDL script, CSV for bcp with data, PPTX, T-SQL Cheat Sheet and teaching tips. Enjoy!do-Dots open .NET SDK: The do-Dots open SDK brings developers a full set of classes that allow to build applications based on do-Dots, a framework for M2M communication. It's developed in C#. EFMVC - ASP.NET MVC 3 and EF Code First: Demo web app using ASP.NET MVC 3 and EF Code FirstGS1: D is a 2D game demo written in C++ and using an API : HAPI for the graphic part and the audio part. All the xml files are handled with tinyXML. It is a vertical scrolling shoot'em up where the player controls a dragon flying in Central Park.GS2: In Zombies, you are a wizard, the most powerful wizard in the world, and two days ago, the Devil forces began to attack our world. The only person capable of stopping them is you, this is why the Devil himself came to you and took your powers. You're now alone, without any weaponIPProvider: DFGiwtfly: ????iwtfly26050: iwtfly2Knowledge Exchange .Net: This is my learning experience with creating an enterprise scale .NET application with tools such as Tortoise SVN, NANT, and Linq to SQLLinqPad Data Context Driver for SharePoint: The SharePoint Data Context Driver for LinqPad makes it easer for SharePoint 2010 Developers to develop, maintain and just play around with Linq To SharePoint statements via LinqPad. It is developed in C# and enables SharePoint 2010 Support to LinqPad.MaxLeafWebSiteK3: MaxLeafWebSiteK3Open ASP.NET CMS: Open ASP.NET 3.5 CMS Plug 'N Play Settings Manager: Plug 'N Play Settings Manager will be an application to configure settings on a windows computer by waiting for a usb thumbstick with a configuration file to be inserted, the application would then read and apply those settings. The early focus will be applying network settings.project windy: Windy - enhanced window manager. windy does window management a breeze. It started as a windows alternative to divvy, but now it has evolved with into its own. Thanks to the generous feedback from you folks. whats different from divvy? - first - its free. - has divvy likeRiaMVVM : MVVM Friendly WCF Ria Services: Simple, light-weight, MVVM friendly access to WCF Ria Services. Written in C# for use with Silverlight 4.SharePoint Designer 2007 Policy: Enable or Disable SharePoint Designer 2007 per site web application and per site colleciton. Spruckus - SharePoint ReUsable Content Keystamp Usage Search: Adds a keystamp to all html type items in the SharePoint Reusable Content list and adds a context item to the reusable content list that will find usages of that reusable content in your site using search.Student Insiders: Student InsidersTea: Tea Web Operator SystemVegas.NET: Projeto teste de TransportadoraXNA 4 Game state management system: XNA 4 Game State Management??????: aa

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  • C#/.NET Little Wonders: Interlocked CompareExchange()

    - by James Michael Hare
    Once again, in this series of posts I look at the parts of the .NET Framework that may seem trivial, but can help improve your code by making it easier to write and maintain. The index of all my past little wonders posts can be found here. Two posts ago, I discussed the Interlocked Add(), Increment(), and Decrement() methods (here) for adding and subtracting values in a thread-safe, lightweight manner.  Then, last post I talked about the Interlocked Read() and Exchange() methods (here) for safely and efficiently reading and setting 32 or 64 bit values (or references).  This week, we’ll round out the discussion by talking about the Interlocked CompareExchange() method and how it can be put to use to exchange a value if the current value is what you expected it to be. Dirty reads can lead to bad results Many of the uses of Interlocked that we’ve explored so far have centered around either reading, setting, or adding values.  But what happens if you want to do something more complex such as setting a value based on the previous value in some manner? Perhaps you were creating an application that reads a current balance, applies a deposit, and then saves the new modified balance, where of course you’d want that to happen atomically.  If you read the balance, then go to save the new balance and between that time the previous balance has already changed, you’ll have an issue!  Think about it, if we read the current balance as $400, and we are applying a new deposit of $50.75, but meanwhile someone else deposits $200 and sets the total to $600, but then we write a total of $450.75 we’ve lost $200! Now, certainly for int and long values we can use Interlocked.Add() to handles these cases, and it works well for that.  But what if we want to work with doubles, for example?  Let’s say we wanted to add the numbers from 0 to 99,999 in parallel.  We could do this by spawning several parallel tasks to continuously add to a total: 1: double total = 0; 2:  3: Parallel.For(0, 10000, next => 4: { 5: total += next; 6: }); Were this run on one thread using a standard for loop, we’d expect an answer of 4,999,950,000 (the sum of all numbers from 0 to 99,999).  But when we run this in parallel as written above, we’ll likely get something far off.  The result of one of my runs, for example, was 1,281,880,740.  That is way off!  If this were banking software we’d be in big trouble with our clients.  So what happened?  The += operator is not atomic, it will read in the current value, add the result, then store it back into the total.  At any point in all of this another thread could read a “dirty” current total and accidentally “skip” our add.   So, to clean this up, we could use a lock to guarantee concurrency: 1: double total = 0.0; 2: object locker = new object(); 3:  4: Parallel.For(0, count, next => 5: { 6: lock (locker) 7: { 8: total += next; 9: } 10: }); Which will give us the correct result of 4,999,950,000.  One thing to note is that locking can be heavy, especially if the operation being locked over is trivial, or the life of the lock is a high percentage of the work being performed concurrently.  In the case above, the lock consumes pretty much all of the time of each parallel task – and the task being locked on is relatively trivial. Now, let me put in a disclaimer here before we go further: For most uses, lock is more than sufficient for your needs, and is often the simplest solution!    So, if lock is sufficient for most needs, why would we ever consider another solution?  The problem with locking is that it can suspend execution of your thread while it waits for the signal that the lock is free.  Moreover, if the operation being locked over is trivial, the lock can add a very high level of overhead.  This is why things like Interlocked.Increment() perform so well, instead of locking just to perform an increment, we perform the increment with an atomic, lockless method. As with all things performance related, it’s important to profile before jumping to the conclusion that you should optimize everything in your path.  If your profiling shows that locking is causing a high level of waiting in your application, then it’s time to consider lighter alternatives such as Interlocked. CompareExchange() – Exchange existing value if equal some value So let’s look at how we could use CompareExchange() to solve our problem above.  The general syntax of CompareExchange() is: T CompareExchange<T>(ref T location, T newValue, T expectedValue) If the value in location == expectedValue, then newValue is exchanged.  Either way, the value in location (before exchange) is returned. Actually, CompareExchange() is not one method, but a family of overloaded methods that can take int, long, float, double, pointers, or references.  It cannot take other value types (that is, can’t CompareExchange() two DateTime instances directly).  Also keep in mind that the version that takes any reference type (the generic overload) only checks for reference equality, it does not call any overridden Equals(). So how does this help us?  Well, we can grab the current total, and exchange the new value if total hasn’t changed.  This would look like this: 1: // grab the snapshot 2: double current = total; 3:  4: // if the total hasn’t changed since I grabbed the snapshot, then 5: // set it to the new total 6: Interlocked.CompareExchange(ref total, current + next, current); So what the code above says is: if the amount in total (1st arg) is the same as the amount in current (3rd arg), then set total to current + next (2nd arg).  This check and exchange pair is atomic (and thus thread-safe). This works if total is the same as our snapshot in current, but the problem, is what happens if they aren’t the same?  Well, we know that in either case we will get the previous value of total (before the exchange), back as a result.  Thus, we can test this against our snapshot to see if it was the value we expected: 1: // if the value returned is != current, then our snapshot must be out of date 2: // which means we didn't (and shouldn't) apply current + next 3: if (Interlocked.CompareExchange(ref total, current + next, current) != current) 4: { 5: // ooops, total was not equal to our snapshot in current, what should we do??? 6: } So what do we do if we fail?  That’s up to you and the problem you are trying to solve.  It’s possible you would decide to abort the whole transaction, or perhaps do a lightweight spin and try again.  Let’s try that: 1: double current = total; 2:  3: // make first attempt... 4: if (Interlocked.CompareExchange(ref total, current + i, current) != current) 5: { 6: // if we fail, go into a spin wait, spin, and try again until succeed 7: var spinner = new SpinWait(); 8:  9: do 10: { 11: spinner.SpinOnce(); 12: current = total; 13: } 14: while (Interlocked.CompareExchange(ref total, current + i, current) != current); 15: } 16:  This is not trivial code, but it illustrates a possible use of CompareExchange().  What we are doing is first checking to see if we succeed on the first try, and if so great!  If not, we create a SpinWait and then repeat the process of SpinOnce(), grab a fresh snapshot, and repeat until CompareExchnage() succeeds.  You may wonder why not a simple do-while here, and the reason it’s more efficient to only create the SpinWait until we absolutely know we need one, for optimal efficiency. Though not as simple (or maintainable) as a simple lock, this will perform better in many situations.  Comparing an unlocked (and wrong) version, a version using lock, and the Interlocked of the code, we get the following average times for multiple iterations of adding the sum of 100,000 numbers: 1: Unlocked money average time: 2.1 ms 2: Locked money average time: 5.1 ms 3: Interlocked money average time: 3 ms So the Interlocked.CompareExchange(), while heavier to code, came in lighter than the lock, offering a good compromise of safety and performance when we need to reduce contention. CompareExchange() - it’s not just for adding stuff… So that was one simple use of CompareExchange() in the context of adding double values -- which meant we couldn’t have used the simpler Interlocked.Add() -- but it has other uses as well. If you think about it, this really works anytime you want to create something new based on a current value without using a full lock.  For example, you could use it to create a simple lazy instantiation implementation.  In this case, we want to set the lazy instance only if the previous value was null: 1: public static class Lazy<T> where T : class, new() 2: { 3: private static T _instance; 4:  5: public static T Instance 6: { 7: get 8: { 9: // if current is null, we need to create new instance 10: if (_instance == null) 11: { 12: // attempt create, it will only set if previous was null 13: Interlocked.CompareExchange(ref _instance, new T(), (T)null); 14: } 15:  16: return _instance; 17: } 18: } 19: } So, if _instance == null, this will create a new T() and attempt to exchange it with _instance.  If _instance is not null, then it does nothing and we discard the new T() we created. This is a way to create lazy instances of a type where we are more concerned about locking overhead than creating an accidental duplicate which is not used.  In fact, the BCL implementation of Lazy<T> offers a similar thread-safety choice for Publication thread safety, where it will not guarantee only one instance was created, but it will guarantee that all readers get the same instance.  Another possible use would be in concurrent collections.  Let’s say, for example, that you are creating your own brand new super stack that uses a linked list paradigm and is “lock free”.  We could use Interlocked.CompareExchange() to be able to do a lockless Push() which could be more efficient in multi-threaded applications where several threads are pushing and popping on the stack concurrently. Yes, there are already concurrent collections in the BCL (in .NET 4.0 as part of the TPL), but it’s a fun exercise!  So let’s assume we have a node like this: 1: public sealed class Node<T> 2: { 3: // the data for this node 4: public T Data { get; set; } 5:  6: // the link to the next instance 7: internal Node<T> Next { get; set; } 8: } Then, perhaps, our stack’s Push() operation might look something like: 1: public sealed class SuperStack<T> 2: { 3: private volatile T _head; 4:  5: public void Push(T value) 6: { 7: var newNode = new Node<int> { Data = value, Next = _head }; 8:  9: if (Interlocked.CompareExchange(ref _head, newNode, newNode.Next) != newNode.Next) 10: { 11: var spinner = new SpinWait(); 12:  13: do 14: { 15: spinner.SpinOnce(); 16: newNode.Next = _head; 17: } 18: while (Interlocked.CompareExchange(ref _head, newNode, newNode.Next) != newNode.Next); 19: } 20: } 21:  22: // ... 23: } Notice a similar paradigm here as with adding our doubles before.  What we are doing is creating the new Node with the data to push, and with a Next value being the original node referenced by _head.  This will create our stack behavior (LIFO – Last In, First Out).  Now, we have to set _head to now refer to the newNode, but we must first make sure it hasn’t changed! So we check to see if _head has the same value we saved in our snapshot as newNode.Next, and if so, we set _head to newNode.  This is all done atomically, and the result is _head’s original value, as long as the original value was what we assumed it was with newNode.Next, then we are good and we set it without a lock!  If not, we SpinWait and try again. Once again, this is much lighter than locking in highly parallelized code with lots of contention.  If I compare the method above with a similar class using lock, I get the following results for pushing 100,000 items: 1: Locked SuperStack average time: 6 ms 2: Interlocked SuperStack average time: 4.5 ms So, once again, we can get more efficient than a lock, though there is the cost of added code complexity.  Fortunately for you, most of the concurrent collection you’d ever need are already created for you in the System.Collections.Concurrent (here) namespace – for more information, see my Little Wonders – The Concurent Collections Part 1 (here), Part 2 (here), and Part 3 (here). Summary We’ve seen before how the Interlocked class can be used to safely and efficiently add, increment, decrement, read, and exchange values in a multi-threaded environment.  In addition to these, Interlocked CompareExchange() can be used to perform more complex logic without the need of a lock when lock contention is a concern. The added efficiency, though, comes at the cost of more complex code.  As such, the standard lock is often sufficient for most thread-safety needs.  But if profiling indicates you spend a lot of time waiting for locks, or if you just need a lock for something simple such as an increment, decrement, read, exchange, etc., then consider using the Interlocked class’s methods to reduce wait. Technorati Tags: C#,CSharp,.NET,Little Wonders,Interlocked,CompareExchange,threading,concurrency

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  • .NET Code Evolution

    - by Alois Kraus
    Originally posted on: http://geekswithblogs.net/akraus1/archive/2013/07/24/153504.aspxAt my day job I do look at a lot of code written by other people. Most of the code is quite good and some is even a masterpiece. And there is also code which makes you think WTF… oh it was written by me. Hm not so bad after all. There are many excuses reasons for bad code. Most often it is time pressure followed by not enough ambition (who cares) or insufficient training. Normally I do care about code quality quite a lot which makes me a (perceived) slow worker who does write many tests and refines the code quite a lot because of the design deficiencies. Most of the deficiencies I do find by putting my design under stress while checking for invariants. It does also help a lot to step into the code with a debugger (sometimes also Windbg). I do this much more often when my tests are red. That way I do get a much better understanding what my code really does and not what I think it should be doing. This time I do want to show you how code can evolve over the years with different .NET Framework versions. Once there was  time where .NET 1.1 was new and many C++ programmers did switch over to get rid of not initialized pointers and memory leaks. There were also nice new data structures available such as the Hashtable which is fast lookup table with O(1) time complexity. All was good and much code was written since then. At 2005 a new version of the .NET Framework did arrive which did bring many new things like generics and new data structures. The “old” fashioned way of Hashtable were coming to an end and everyone used the new Dictionary<xx,xx> type instead which was type safe and faster because the object to type conversion (aka boxing) was no longer necessary. I think 95% of all Hashtables and dictionaries use string as key. Often it is convenient to ignore casing to make it easy to look up values which the user did enter. An often followed route is to convert the string to upper case before putting it into the Hashtable. Hashtable Table = new Hashtable(); void Add(string key, string value) { Table.Add(key.ToUpper(), value); } This is valid and working code but it has problems. First we can pass to the Hashtable a custom IEqualityComparer to do the string matching case insensitive. Second we can switch over to the now also old Dictionary type to become a little faster and we can keep the the original keys (not upper cased) in the dictionary. Dictionary<string, string> DictTable = new Dictionary<string, string>(StringComparer.OrdinalIgnoreCase); void AddDict(string key, string value) { DictTable.Add(key, value); } Many people do not user the other ctors of Dictionary because they do shy away from the overhead of writing their own comparer. They do not know that .NET has for strings already predefined comparers at hand which you can directly use. Today in the many core area we do use threads all over the place. Sometimes things break in subtle ways but most of the time it is sufficient to place a lock around the offender. Threading has become so mainstream that it may sound weird that in the year 2000 some guy got a huge incentive for the idea to reduce the time to process calibration data from 12 hours to 6 hours by using two threads on a dual core machine. Threading does make it easy to become faster at the expense of correctness. Correct and scalable multithreading can be arbitrarily hard to achieve depending on the problem you are trying to solve. Lets suppose we want to process millions of items with two threads and count the processed items processed by all threads. A typical beginners code might look like this: int Counter; void IJustLearnedToUseThreads() { var t1 = new Thread(ThreadWorkMethod); t1.Start(); var t2 = new Thread(ThreadWorkMethod); t2.Start(); t1.Join(); t2.Join(); if (Counter != 2 * Increments) throw new Exception("Hmm " + Counter + " != " + 2 * Increments); } const int Increments = 10 * 1000 * 1000; void ThreadWorkMethod() { for (int i = 0; i < Increments; i++) { Counter++; } } It does throw an exception with the message e.g. “Hmm 10.222.287 != 20.000.000” and does never finish. The code does fail because the assumption that Counter++ is an atomic operation is wrong. The ++ operator is just a shortcut for Counter = Counter + 1 This does involve reading the counter from a memory location into the CPU, incrementing value on the CPU and writing the new value back to the memory location. When we do look at the generated assembly code we will see only inc dword ptr [ecx+10h] which is only one instruction. Yes it is one instruction but it is not atomic. All modern CPUs have several layers of caches (L1,L2,L3) which try to hide the fact how slow actual main memory accesses are. Since cache is just another word for redundant copy it can happen that one CPU does read a value from main memory into the cache, modifies it and write it back to the main memory. The problem is that at least the L1 cache is not shared between CPUs so it can happen that one CPU does make changes to values which did change in meantime in the main memory. From the exception you can see we did increment the value 20 million times but half of the changes were lost because we did overwrite the already changed value from the other thread. This is a very common case and people do learn to protect their  data with proper locking.   void Intermediate() { var time = Stopwatch.StartNew(); Action acc = ThreadWorkMethod_Intermediate; var ar1 = acc.BeginInvoke(null, null); var ar2 = acc.BeginInvoke(null, null); ar1.AsyncWaitHandle.WaitOne(); ar2.AsyncWaitHandle.WaitOne(); if (Counter != 2 * Increments) throw new Exception(String.Format("Hmm {0:N0} != {1:N0}", Counter, 2 * Increments)); Console.WriteLine("Intermediate did take: {0:F1}s", time.Elapsed.TotalSeconds); } void ThreadWorkMethod_Intermediate() { for (int i = 0; i < Increments; i++) { lock (this) { Counter++; } } } This is better and does use the .NET Threadpool to get rid of manual thread management. It does give the expected result but it can result in deadlocks because you do lock on this. This is in general a bad idea since it can lead to deadlocks when other threads use your class instance as lock object. It is therefore recommended to create a private object as lock object to ensure that nobody else can lock your lock object. When you read more about threading you will read about lock free algorithms. They are nice and can improve performance quite a lot but you need to pay close attention to the CLR memory model. It does make quite weak guarantees in general but it can still work because your CPU architecture does give you more invariants than the CLR memory model. For a simple counter there is an easy lock free alternative present with the Interlocked class in .NET. As a general rule you should not try to write lock free algos since most likely you will fail to get it right on all CPU architectures. void Experienced() { var time = Stopwatch.StartNew(); Task t1 = Task.Factory.StartNew(ThreadWorkMethod_Experienced); Task t2 = Task.Factory.StartNew(ThreadWorkMethod_Experienced); t1.Wait(); t2.Wait(); if (Counter != 2 * Increments) throw new Exception(String.Format("Hmm {0:N0} != {1:N0}", Counter, 2 * Increments)); Console.WriteLine("Experienced did take: {0:F1}s", time.Elapsed.TotalSeconds); } void ThreadWorkMethod_Experienced() { for (int i = 0; i < Increments; i++) { Interlocked.Increment(ref Counter); } } Since time does move forward we do not use threads explicitly anymore but the much nicer Task abstraction which was introduced with .NET 4 at 2010. It is educational to look at the generated assembly code. The Interlocked.Increment method must be called which does wondrous things right? Lets see: lock inc dword ptr [eax] The first thing to note that there is no method call at all. Why? Because the JIT compiler does know very well about CPU intrinsic functions. Atomic operations which do lock the memory bus to prevent other processors to read stale values are such things. Second: This is the same increment call prefixed with a lock instruction. The only reason for the existence of the Interlocked class is that the JIT compiler can compile it to the matching CPU intrinsic functions which can not only increment by one but can also do an add, exchange and a combined compare and exchange operation. But be warned that the correct usage of its methods can be tricky. If you try to be clever and look a the generated IL code and try to reason about its efficiency you will fail. Only the generated machine code counts. Is this the best code we can write? Perhaps. It is nice and clean. But can we make it any faster? Lets see how good we are doing currently. Level Time in s IJustLearnedToUseThreads Flawed Code Intermediate 1,5 (lock) Experienced 0,3 (Interlocked.Increment) Master 0,1 (1,0 for int[2]) That lock free thing is really a nice thing. But if you read more about CPU cache, cache coherency, false sharing you can do even better. int[] Counters = new int[12]; // Cache line size is 64 bytes on my machine with an 8 way associative cache try for yourself e.g. 64 on more modern CPUs void Master() { var time = Stopwatch.StartNew(); Task t1 = Task.Factory.StartNew(ThreadWorkMethod_Master, 0); Task t2 = Task.Factory.StartNew(ThreadWorkMethod_Master, Counters.Length - 1); t1.Wait(); t2.Wait(); Counter = Counters[0] + Counters[Counters.Length - 1]; if (Counter != 2 * Increments) throw new Exception(String.Format("Hmm {0:N0} != {1:N0}", Counter, 2 * Increments)); Console.WriteLine("Master did take: {0:F1}s", time.Elapsed.TotalSeconds); } void ThreadWorkMethod_Master(object number) { int index = (int) number; for (int i = 0; i < Increments; i++) { Counters[index]++; } } The key insight here is to use for each core its own value. But if you simply use simply an integer array of two items, one for each core and add the items at the end you will be much slower than the lock free version (factor 3). Each CPU core has its own cache line size which is something in the range of 16-256 bytes. When you do access a value from one location the CPU does not only fetch one value from main memory but a complete cache line (e.g. 16 bytes). This means that you do not pay for the next 15 bytes when you access them. This can lead to dramatic performance improvements and non obvious code which is faster although it does have many more memory reads than another algorithm. So what have we done here? We have started with correct code but it was lacking knowledge how to use the .NET Base Class Libraries optimally. Then we did try to get fancy and used threads for the first time and failed. Our next try was better but it still had non obvious issues (lock object exposed to the outside). Knowledge has increased further and we have found a lock free version of our counter which is a nice and clean way which is a perfectly valid solution. The last example is only here to show you how you can get most out of threading by paying close attention to your used data structures and CPU cache coherency. Although we are working in a virtual execution environment in a high level language with automatic memory management it does pay off to know the details down to the assembly level. Only if you continue to learn and to dig deeper you can come up with solutions no one else was even considering. I have studied particle physics which does help at the digging deeper part. Have you ever tried to solve Quantum Chromodynamics equations? Compared to that the rest must be easy ;-). Although I am no longer working in the Science field I take pride in discovering non obvious things. This can be a very hard to find bug or a new way to restructure data to make something 10 times faster. Now I need to get some sleep ….

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  • Top things web developers should know about the Visual Studio 2013 release

    - by Jon Galloway
    ASP.NET and Web Tools for Visual Studio 2013 Release NotesASP.NET and Web Tools for Visual Studio 2013 Release NotesSummary for lazy readers: Visual Studio 2013 is now available for download on the Visual Studio site and on MSDN subscriber downloads) Visual Studio 2013 installs side by side with Visual Studio 2012 and supports round-tripping between Visual Studio versions, so you can try it out without committing to a switch Visual Studio 2013 ships with the new version of ASP.NET, which includes ASP.NET MVC 5, ASP.NET Web API 2, Razor 3, Entity Framework 6 and SignalR 2.0 The new releases ASP.NET focuses on One ASP.NET, so core features and web tools work the same across the platform (e.g. adding ASP.NET MVC controllers to a Web Forms application) New core features include new templates based on Bootstrap, a new scaffolding system, and a new identity system Visual Studio 2013 is an incredible editor for web files, including HTML, CSS, JavaScript, Markdown, LESS, Coffeescript, Handlebars, Angular, Ember, Knockdown, etc. Top links: Visual Studio 2013 content on the ASP.NET site are in the standard new releases area: http://www.asp.net/vnext ASP.NET and Web Tools for Visual Studio 2013 Release Notes Short intro videos on the new Visual Studio web editor features from Scott Hanselman and Mads Kristensen Announcing release of ASP.NET and Web Tools for Visual Studio 2013 post on the official .NET Web Development and Tools Blog Scott Guthrie's post: Announcing the Release of Visual Studio 2013 and Great Improvements to ASP.NET and Entity Framework Okay, for those of you who are still with me, let's dig in a bit. Quick web dev notes on downloading and installing Visual Studio 2013 I found Visual Studio 2013 to be a pretty fast install. According to Brian Harry's release post, installing over pre-release versions of Visual Studio is supported.  I've installed the release version over pre-release versions, and it worked fine. If you're only going to be doing web development, you can speed up the install if you just select Web Developer tools. Of course, as a good Microsoft employee, I'll mention that you might also want to install some of those other features, like the Store apps for Windows 8 and the Windows Phone 8.0 SDK, but they do download and install a lot of other stuff (e.g. the Windows Phone SDK sets up Hyper-V and downloads several GB's of VM's). So if you're planning just to do web development for now, you can pick just the Web Developer Tools and install the other stuff later. If you've got a fast internet connection, I recommend using the web installer instead of downloading the ISO. The ISO includes all the features, whereas the web installer just downloads what you're installing. Visual Studio 2013 development settings and color theme When you start up Visual Studio, it'll prompt you to pick some defaults. These are totally up to you -whatever suits your development style - and you can change them later. As I said, these are completely up to you. I recommend either the Web Development or Web Development (Code Only) settings. The only real difference is that Code Only hides the toolbars, and you can switch between them using Tools / Import and Export Settings / Reset. Web Development settings Web Development (code only) settings Usually I've just gone with Web Development (code only) in the past because I just want to focus on the code, although the Standard toolbar does make it easier to switch default web browsers. More on that later. Color theme Sigh. Okay, everyone's got their favorite colors. I alternate between Light and Dark depending on my mood, and I personally like how the low contrast on the window chrome in those themes puts the emphasis on my code rather than the tabs and toolbars. I know some people got pretty worked up over that, though, and wanted the blue theme back. I personally don't like it - it reminds me of ancient versions of Visual Studio that I don't want to think about anymore. So here's the thing: if you install Visual Studio Ultimate, it defaults to Blue. The other versions default to Light. If you use Blue, I won't criticize you - out loud, that is. You can change themes really easily - either Tools / Options / Environment / General, or the smart way: ctrl+q for quick launch, then type Theme and hit enter. Signing in During the first run, you'll be prompted to sign in. You don't have to - you can click the "Not now, maybe later" link at the bottom of that dialog. I recommend signing in, though. It's not hooked in with licensing or tracking the kind of code you write to sell you components. It is doing good things, like  syncing your Visual Studio settings between computers. More about that here. So, you don't have to, but I sure do. Overview of shiny new things in ASP.NET land There are a lot of good new things in ASP.NET. I'll list some of my favorite here, but you can read more on the ASP.NET site. One ASP.NET You've heard us talk about this for a while. The idea is that options are good, but choice can be a burden. When you start a new ASP.NET project, why should you have to make a tough decision - with long-term consequences - about how your application will work? If you want to use ASP.NET Web Forms, but have the option of adding in ASP.NET MVC later, why should that be hard? It's all ASP.NET, right? Ideally, you'd just decide that you want to use ASP.NET to build sites and services, and you could use the appropriate tools (the green blocks below) as you needed them. So, here it is. When you create a new ASP.NET application, you just create an ASP.NET application. Next, you can pick from some templates to get you started... but these are different. They're not "painful decision" templates, they're just some starting pieces. And, most importantly, you can mix and match. I can pick a "mostly" Web Forms template, but include MVC and Web API folders and core references. If you've tried to mix and match in the past, you're probably aware that it was possible, but not pleasant. ASP.NET MVC project files contained special project type GUIDs, so you'd only get controller scaffolding support in a Web Forms project if you manually edited the csproj file. Features in one stack didn't work in others. Project templates were painful choices. That's no longer the case. Hooray! I just did a demo in a presentation last week where I created a new Web Forms + MVC + Web API site, built a model, scaffolded MVC and Web API controllers with EF Code First, add data in the MVC view, viewed it in Web API, then added a GridView to the Web Forms Default.aspx page and bound it to the Model. In about 5 minutes. Sure, it's a simple example, but it's great to be able to share code and features across the whole ASP.NET family. Authentication In the past, authentication was built into the templates. So, for instance, there was an ASP.NET MVC 4 Intranet Project template which created a new ASP.NET MVC 4 application that was preconfigured for Windows Authentication. All of that authentication stuff was built into each template, so they varied between the stacks, and you couldn't reuse them. You didn't see a lot of changes to the authentication options, since they required big changes to a bunch of project templates. Now, the new project dialog includes a common authentication experience. When you hit the Change Authentication button, you get some common options that work the same way regardless of the template or reference settings you've made. These options work on all ASP.NET frameworks, and all hosting environments (IIS, IIS Express, or OWIN for self-host) The default is Individual User Accounts: This is the standard "create a local account, using username / password or OAuth" thing; however, it's all built on the new Identity system. More on that in a second. The one setting that has some configuration to it is Organizational Accounts, which lets you configure authentication using Active Directory, Windows Azure Active Directory, or Office 365. Identity There's a new identity system. We've taken the best parts of the previous ASP.NET Membership and Simple Identity systems, rolled in a lot of feedback and made big enhancements to support important developer concerns like unit testing and extensiblity. I've written long posts about ASP.NET identity, and I'll do it again. Soon. This is not that post. The short version is that I think we've finally got just the right Identity system. Some of my favorite features: There are simple, sensible defaults that work well - you can File / New / Run / Register / Login, and everything works. It supports standard username / password as well as external authentication (OAuth, etc.). It's easy to customize without having to re-implement an entire provider. It's built using pluggable pieces, rather than one large monolithic system. It's built using interfaces like IUser and IRole that allow for unit testing, dependency injection, etc. You can easily add user profile data (e.g. URL, twitter handle, birthday). You just add properties to your ApplicationUser model and they'll automatically be persisted. Complete control over how the identity data is persisted. By default, everything works with Entity Framework Code First, but it's built to support changes from small (modify the schema) to big (use another ORM, store your data in a document database or in the cloud or in XML or in the EXIF data of your desktop background or whatever). It's configured via OWIN. More on OWIN and Katana later, but the fact that it's built using OWIN means it's portable. You can find out more in the Authentication and Identity section of the ASP.NET site (and lots more content will be going up there soon). New Bootstrap based project templates The new project templates are built using Bootstrap 3. Bootstrap (formerly Twitter Bootstrap) is a front-end framework that brings a lot of nice benefits: It's responsive, so your projects will automatically scale to device width using CSS media queries. For example, menus are full size on a desktop browser, but on narrower screens you automatically get a mobile-friendly menu. The built-in Bootstrap styles make your standard page elements (headers, footers, buttons, form inputs, tables etc.) look nice and modern. Bootstrap is themeable, so you can reskin your whole site by dropping in a new Bootstrap theme. Since Bootstrap is pretty popular across the web development community, this gives you a large and rapidly growing variety of templates (free and paid) to choose from. Bootstrap also includes a lot of very useful things: components (like progress bars and badges), useful glyphicons, and some jQuery plugins for tooltips, dropdowns, carousels, etc.). Here's a look at how the responsive part works. When the page is full screen, the menu and header are optimized for a wide screen display: When I shrink the page down (this is all based on page width, not useragent sniffing) the menu turns into a nice mobile-friendly dropdown: For a quick example, I grabbed a new free theme off bootswatch.com. For simple themes, you just need to download the boostrap.css file and replace the /content/bootstrap.css file in your project. Now when I refresh the page, I've got a new theme: Scaffolding The big change in scaffolding is that it's one system that works across ASP.NET. You can create a new Empty Web project or Web Forms project and you'll get the Scaffold context menus. For release, we've got MVC 5 and Web API 2 controllers. We had a preview of Web Forms scaffolding in the preview releases, but they weren't fully baked for RTM. Look for them in a future update, expected pretty soon. This scaffolding system wasn't just changed to work across the ASP.NET frameworks, it's also built to enable future extensibility. That's not in this release, but should also hopefully be out soon. Project Readme page This is a small thing, but I really like it. When you create a new project, you get a Project_Readme.html page that's added to the root of your project and opens in the Visual Studio built-in browser. I love it. A long time ago, when you created a new project we just dumped it on you and left you scratching your head about what to do next. Not ideal. Then we started adding a bunch of Getting Started information to the new project templates. That told you what to do next, but you had to delete all of that stuff out of your website. It doesn't belong there. Not ideal. This is a simple HTML file that's not integrated into your project code at all. You can delete it if you want. But, it shows a lot of helpful links that are current for the project you just created. In the future, if we add new wacky project types, they can create readme docs with specific information on how to do appropriately wacky things. Side note: I really like that they used the internal browser in Visual Studio to show this content rather than popping open an HTML page in the default browser. I hate that. It's annoying. If you're doing that, I hope you'll stop. What if some unnamed person has 40 or 90 tabs saved in their browser session? When you pop open your "Thanks for installing my Visual Studio extension!" page, all eleventy billion tabs start up and I wish I'd never installed your thing. Be like these guys and pop stuff Visual Studio specific HTML docs in the Visual Studio browser. ASP.NET MVC 5 The biggest change with ASP.NET MVC 5 is that it's no longer a separate project type. It integrates well with the rest of ASP.NET. In addition to that and the other common features we've already looked at (Bootstrap templates, Identity, authentication), here's what's new for ASP.NET MVC. Attribute routing ASP.NET MVC now supports attribute routing, thanks to a contribution by Tim McCall, the author of http://attributerouting.net. With attribute routing you can specify your routes by annotating your actions and controllers. This supports some pretty complex, customized routing scenarios, and it allows you to keep your route information right with your controller actions if you'd like. Here's a controller that includes an action whose method name is Hiding, but I've used AttributeRouting to configure it to /spaghetti/with-nesting/where-is-waldo public class SampleController : Controller { [Route("spaghetti/with-nesting/where-is-waldo")] public string Hiding() { return "You found me!"; } } I enable that in my RouteConfig.cs, and I can use that in conjunction with my other MVC routes like this: public class RouteConfig { public static void RegisterRoutes(RouteCollection routes) { routes.IgnoreRoute("{resource}.axd/{*pathInfo}"); routes.MapMvcAttributeRoutes(); routes.MapRoute( name: "Default", url: "{controller}/{action}/{id}", defaults: new { controller = "Home", action = "Index", id = UrlParameter.Optional } ); } } You can read more about Attribute Routing in ASP.NET MVC 5 here. Filter enhancements There are two new additions to filters: Authentication Filters and Filter Overrides. Authentication filters are a new kind of filter in ASP.NET MVC that run prior to authorization filters in the ASP.NET MVC pipeline and allow you to specify authentication logic per-action, per-controller, or globally for all controllers. Authentication filters process credentials in the request and provide a corresponding principal. Authentication filters can also add authentication challenges in response to unauthorized requests. Override filters let you change which filters apply to a given action method or controller. Override filters specify a set of filter types that should not be run for a given scope (action or controller). This allows you to configure filters that apply globally but then exclude certain global filters from applying to specific actions or controllers. ASP.NET Web API 2 ASP.NET Web API 2 includes a lot of new features. Attribute Routing ASP.NET Web API supports the same attribute routing system that's in ASP.NET MVC 5. You can read more about the Attribute Routing features in Web API in this article. OAuth 2.0 ASP.NET Web API picks up OAuth 2.0 support, using security middleware running on OWIN (discussed below). This is great for features like authenticated Single Page Applications. OData Improvements ASP.NET Web API now has full OData support. That required adding in some of the most powerful operators: $select, $expand, $batch and $value. You can read more about OData operator support in this article by Mike Wasson. Lots more There's a huge list of other features, including CORS (cross-origin request sharing), IHttpActionResult, IHttpRequestContext, and more. I think the best overview is in the release notes. OWIN and Katana I've written about OWIN and Katana recently. I'm a big fan. OWIN is the Open Web Interfaces for .NET. It's a spec, like HTML or HTTP, so you can't install OWIN. The benefit of OWIN is that it's a community specification, so anyone who implements it can plug into the ASP.NET stack, either as middleware or as a host. Katana is the Microsoft implementation of OWIN. It leverages OWIN to wire up things like authentication, handlers, modules, IIS hosting, etc., so ASP.NET can host OWIN components and Katana components can run in someone else's OWIN implementation. Howard Dierking just wrote a cool article in MSDN magazine describing Katana in depth: Getting Started with the Katana Project. He had an interesting example showing an OWIN based pipeline which leveraged SignalR, ASP.NET Web API and NancyFx components in the same stack. If this kind of thing makes sense to you, that's great. If it doesn't, don't worry, but keep an eye on it. You're going to see some cool things happen as a result of ASP.NET becoming more and more pluggable. Visual Studio Web Tools Okay, this stuff's just crazy. Visual Studio has been adding some nice web dev features over the past few years, but they've really cranked it up for this release. Visual Studio is by far my favorite code editor for all web files: CSS, HTML, JavaScript, and lots of popular libraries. Stop thinking of Visual Studio as a big editor that you only use to write back-end code. Stop editing HTML and CSS in Notepad (or Sublime, Notepad++, etc.). Visual Studio starts up in under 2 seconds on a modern computer with an SSD. Misspelling HTML attributes or your CSS classes or jQuery or Angular syntax is stupid. It doesn't make you a better developer, it makes you a silly person who wastes time. Browser Link Browser Link is a real-time, two-way connection between Visual Studio and all connected browsers. It's only attached when you're running locally, in debug, but it applies to any and all connected browser, including emulators. You may have seen demos that showed the browsers refreshing based on changes in the editor, and I'll agree that's pretty cool. But it's really just the start. It's a two-way connection, and it's built for extensiblity. That means you can write extensions that push information from your running application (in IE, Chrome, a mobile emulator, etc.) back to Visual Studio. Mads and team have showed off some demonstrations where they enabled edit mode in the browser which updated the source HTML back on the browser. It's also possible to look at how the rendered HTML performs, check for compatibility issues, watch for unused CSS classes, the sky's the limit. New HTML editor The previous HTML editor had a lot of old code that didn't allow for improvements. The team rewrote the HTML editor to take advantage of the new(ish) extensibility features in Visual Studio, which then allowed them to add in all kinds of features - things like CSS Class and ID IntelliSense (so you type style="" and get a list of classes and ID's for your project), smart indent based on how your document is formatted, JavaScript reference auto-sync, etc. Here's a 3 minute tour from Mads Kristensen. The previous HTML editor had a lot of old code that didn't allow for improvements. The team rewrote the HTML editor to take advantage of the new(ish) extensibility features in Visual Studio, which then allowed them to add in all kinds of features - things like CSS Class and ID IntelliSense (so you type style="" and get a list of classes and ID's for your project), smart indent based on how your document is formatted, JavaScript reference auto-sync, etc. Lots more Visual Studio web dev features That's just a sampling - there's a ton of great features for JavaScript editing, CSS editing, publishing, and Page Inspector (which shows real-time rendering of your page inside Visual Studio). Here are some more short videos showing those features. Lots, lots more Okay, that's just a summary, and it's still quite a bit. Head on over to http://asp.net/vnext for more information, and download Visual Studio 2013 now to get started!

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  • The Incremental Architect&rsquo;s Napkin - #5 - Design functions for extensibility and readability

    - by Ralf Westphal
    Originally posted on: http://geekswithblogs.net/theArchitectsNapkin/archive/2014/08/24/the-incremental-architectrsquos-napkin---5---design-functions-for.aspx The functionality of programs is entered via Entry Points. So what we´re talking about when designing software is a bunch of functions handling the requests represented by and flowing in through those Entry Points. Designing software thus consists of at least three phases: Analyzing the requirements to find the Entry Points and their signatures Designing the functionality to be executed when those Entry Points get triggered Implementing the functionality according to the design aka coding I presume, you´re familiar with phase 1 in some way. And I guess you´re proficient in implementing functionality in some programming language. But in my experience developers in general are not experienced in going through an explicit phase 2. “Designing functionality? What´s that supposed to mean?” you might already have thought. Here´s my definition: To design functionality (or functional design for short) means thinking about… well, functions. You find a solution for what´s supposed to happen when an Entry Point gets triggered in terms of functions. A conceptual solution that is, because those functions only exist in your head (or on paper) during this phase. But you may have guess that, because it´s “design” not “coding”. And here is, what functional design is not: It´s not about logic. Logic is expressions (e.g. +, -, && etc.) and control statements (e.g. if, switch, for, while etc.). Also I consider calling external APIs as logic. It´s equally basic. It´s what code needs to do in order to deliver some functionality or quality. Logic is what´s doing that needs to be done by software. Transformations are either done through expressions or API-calls. And then there is alternative control flow depending on the result of some expression. Basically it´s just jumps in Assembler, sometimes to go forward (if, switch), sometimes to go backward (for, while, do). But calling your own function is not logic. It´s not necessary to produce any outcome. Functionality is not enhanced by adding functions (subroutine calls) to your code. Nor is quality increased by adding functions. No performance gain, no higher scalability etc. through functions. Functions are not relevant to functionality. Strange, isn´t it. What they are important for is security of investment. By introducing functions into our code we can become more productive (re-use) and can increase evolvability (higher unterstandability, easier to keep code consistent). That´s no small feat, however. Evolvable code can hardly be overestimated. That´s why to me functional design is so important. It´s at the core of software development. To sum this up: Functional design is on a level of abstraction above (!) logical design or algorithmic design. Functional design is only done until you get to a point where each function is so simple you are very confident you can easily code it. Functional design an logical design (which mostly is coding, but can also be done using pseudo code or flow charts) are complementary. Software needs both. If you start coding right away you end up in a tangled mess very quickly. Then you need back out through refactoring. Functional design on the other hand is bloodless without actual code. It´s just a theory with no experiments to prove it. But how to do functional design? An example of functional design Let´s assume a program to de-duplicate strings. The user enters a number of strings separated by commas, e.g. a, b, a, c, d, b, e, c, a. And the program is supposed to clear this list of all doubles, e.g. a, b, c, d, e. There is only one Entry Point to this program: the user triggers the de-duplication by starting the program with the string list on the command line C:\>deduplicate "a, b, a, c, d, b, e, c, a" a, b, c, d, e …or by clicking on a GUI button. This leads to the Entry Point function to get called. It´s the program´s main function in case of the batch version or a button click event handler in the GUI version. That´s the physical Entry Point so to speak. It´s inevitable. What then happens is a three step process: Transform the input data from the user into a request. Call the request handler. Transform the output of the request handler into a tangible result for the user. Or to phrase it a bit more generally: Accept input. Transform input into output. Present output. This does not mean any of these steps requires a lot of effort. Maybe it´s just one line of code to accomplish it. Nevertheless it´s a distinct step in doing the processing behind an Entry Point. Call it an aspect or a responsibility - and you will realize it most likely deserves a function of its own to satisfy the Single Responsibility Principle (SRP). Interestingly the above list of steps is already functional design. There is no logic, but nevertheless the solution is described - albeit on a higher level of abstraction than you might have done yourself. But it´s still on a meta-level. The application to the domain at hand is easy, though: Accept string list from command line De-duplicate Present de-duplicated strings on standard output And this concrete list of processing steps can easily be transformed into code:static void Main(string[] args) { var input = Accept_string_list(args); var output = Deduplicate(input); Present_deduplicated_string_list(output); } Instead of a big problem there are three much smaller problems now. If you think each of those is trivial to implement, then go for it. You can stop the functional design at this point. But maybe, just maybe, you´re not so sure how to go about with the de-duplication for example. Then just implement what´s easy right now, e.g.private static string Accept_string_list(string[] args) { return args[0]; } private static void Present_deduplicated_string_list( string[] output) { var line = string.Join(", ", output); Console.WriteLine(line); } Accept_string_list() contains logic in the form of an API-call. Present_deduplicated_string_list() contains logic in the form of an expression and an API-call. And then repeat the functional design for the remaining processing step. What´s left is the domain logic: de-duplicating a list of strings. How should that be done? Without any logic at our disposal during functional design you´re left with just functions. So which functions could make up the de-duplication? Here´s a suggestion: De-duplicate Parse the input string into a true list of strings. Register each string in a dictionary/map/set. That way duplicates get cast away. Transform the data structure into a list of unique strings. Processing step 2 obviously was the core of the solution. That´s where real creativity was needed. That´s the core of the domain. But now after this refinement the implementation of each step is easy again:private static string[] Parse_string_list(string input) { return input.Split(',') .Select(s => s.Trim()) .ToArray(); } private static Dictionary<string,object> Compile_unique_strings(string[] strings) { return strings.Aggregate( new Dictionary<string, object>(), (agg, s) => { agg[s] = null; return agg; }); } private static string[] Serialize_unique_strings( Dictionary<string,object> dict) { return dict.Keys.ToArray(); } With these three additional functions Main() now looks like this:static void Main(string[] args) { var input = Accept_string_list(args); var strings = Parse_string_list(input); var dict = Compile_unique_strings(strings); var output = Serialize_unique_strings(dict); Present_deduplicated_string_list(output); } I think that´s very understandable code: just read it from top to bottom and you know how the solution to the problem works. It´s a mirror image of the initial design: Accept string list from command line Parse the input string into a true list of strings. Register each string in a dictionary/map/set. That way duplicates get cast away. Transform the data structure into a list of unique strings. Present de-duplicated strings on standard output You can even re-generate the design by just looking at the code. Code and functional design thus are always in sync - if you follow some simple rules. But about that later. And as a bonus: all the functions making up the process are small - which means easy to understand, too. So much for an initial concrete example. Now it´s time for some theory. Because there is method to this madness ;-) The above has only scratched the surface. Introducing Flow Design Functional design starts with a given function, the Entry Point. Its goal is to describe the behavior of the program when the Entry Point is triggered using a process, not an algorithm. An algorithm consists of logic, a process on the other hand consists just of steps or stages. Each processing step transforms input into output or a side effect. Also it might access resources, e.g. a printer, a database, or just memory. Processing steps thus can rely on state of some sort. This is different from Functional Programming, where functions are supposed to not be stateful and not cause side effects.[1] In its simplest form a process can be written as a bullet point list of steps, e.g. Get data from user Output result to user Transform data Parse data Map result for output Such a compilation of steps - possibly on different levels of abstraction - often is the first artifact of functional design. It can be generated by a team in an initial design brainstorming. Next comes ordering the steps. What should happen first, what next etc.? Get data from user Parse data Transform data Map result for output Output result to user That´s great for a start into functional design. It´s better than starting to code right away on a given function using TDD. Please get me right: TDD is a valuable practice. But it can be unnecessarily hard if the scope of a functionn is too large. But how do you know beforehand without investing some thinking? And how to do this thinking in a systematic fashion? My recommendation: For any given function you´re supposed to implement first do a functional design. Then, once you´re confident you know the processing steps - which are pretty small - refine and code them using TDD. You´ll see that´s much, much easier - and leads to cleaner code right away. For more information on this approach I call “Informed TDD” read my book of the same title. Thinking before coding is smart. And writing down the solution as a bunch of functions possibly is the simplest thing you can do, I´d say. It´s more according to the KISS (Keep It Simple, Stupid) principle than returning constants or other trivial stuff TDD development often is started with. So far so good. A simple ordered list of processing steps will do to start with functional design. As shown in the above example such steps can easily be translated into functions. Moving from design to coding thus is simple. However, such a list does not scale. Processing is not always that simple to be captured in a list. And then the list is just text. Again. Like code. That means the design is lacking visuality. Textual representations need more parsing by your brain than visual representations. Plus they are limited in their “dimensionality”: text just has one dimension, it´s sequential. Alternatives and parallelism are hard to encode in text. In addition the functional design using numbered lists lacks data. It´s not visible what´s the input, output, and state of the processing steps. That´s why functional design should be done using a lightweight visual notation. No tool is necessary to draw such designs. Use pen and paper; a flipchart, a whiteboard, or even a napkin is sufficient. Visualizing processes The building block of the functional design notation is a functional unit. I mostly draw it like this: Something is done, it´s clear what goes in, it´s clear what comes out, and it´s clear what the processing step requires in terms of state or hardware. Whenever input flows into a functional unit it gets processed and output is produced and/or a side effect occurs. Flowing data is the driver of something happening. That´s why I call this approach to functional design Flow Design. It´s about data flow instead of control flow. Control flow like in algorithms is of no concern to functional design. Thinking about control flow simply is too low level. Once you start with control flow you easily get bogged down by tons of details. That´s what you want to avoid during design. Design is supposed to be quick, broad brush, abstract. It should give overview. But what about all the details? As Robert C. Martin rightly said: “Programming is abot detail”. Detail is a matter of code. Once you start coding the processing steps you designed you can worry about all the detail you want. Functional design does not eliminate all the nitty gritty. It just postpones tackling them. To me that´s also an example of the SRP. Function design has the responsibility to come up with a solution to a problem posed by a single function (Entry Point). And later coding has the responsibility to implement the solution down to the last detail (i.e. statement, API-call). TDD unfortunately mixes both responsibilities. It´s just coding - and thereby trying to find detailed implementations (green phase) plus getting the design right (refactoring). To me that´s one reason why TDD has failed to deliver on its promise for many developers. Using functional units as building blocks of functional design processes can be depicted very easily. Here´s the initial process for the example problem: For each processing step draw a functional unit and label it. Choose a verb or an “action phrase” as a label, not a noun. Functional design is about activities, not state or structure. Then make the output of an upstream step the input of a downstream step. Finally think about the data that should flow between the functional units. Write the data above the arrows connecting the functional units in the direction of the data flow. Enclose the data description in brackets. That way you can clearly see if all flows have already been specified. Empty brackets mean “no data is flowing”, but nevertheless a signal is sent. A name like “list” or “strings” in brackets describes the data content. Use lower case labels for that purpose. A name starting with an upper case letter like “String” or “Customer” on the other hand signifies a data type. If you like, you also can combine descriptions with data types by separating them with a colon, e.g. (list:string) or (strings:string[]). But these are just suggestions from my practice with Flow Design. You can do it differently, if you like. Just be sure to be consistent. Flows wired-up in this manner I call one-dimensional (1D). Each functional unit just has one input and/or one output. A functional unit without an output is possible. It´s like a black hole sucking up input without producing any output. Instead it produces side effects. A functional unit without an input, though, does make much sense. When should it start to work? What´s the trigger? That´s why in the above process even the first processing step has an input. If you like, view such 1D-flows as pipelines. Data is flowing through them from left to right. But as you can see, it´s not always the same data. It get´s transformed along its passage: (args) becomes a (list) which is turned into (strings). The Principle of Mutual Oblivion A very characteristic trait of flows put together from function units is: no functional units knows another one. They are all completely independent of each other. Functional units don´t know where their input is coming from (or even when it´s gonna arrive). They just specify a range of values they can process. And they promise a certain behavior upon input arriving. Also they don´t know where their output is going. They just produce it in their own time independent of other functional units. That means at least conceptually all functional units work in parallel. Functional units don´t know their “deployment context”. They now nothing about the overall flow they are place in. They are just consuming input from some upstream, and producing output for some downstream. That makes functional units very easy to test. At least as long as they don´t depend on state or resources. I call this the Principle of Mutual Oblivion (PoMO). Functional units are oblivious of others as well as an overall context/purpose. They are just parts of a whole focused on a single responsibility. How the whole is built, how a larger goal is achieved, is of no concern to the single functional units. By building software in such a manner, functional design interestingly follows nature. Nature´s building blocks for organisms also follow the PoMO. The cells forming your body do not know each other. Take a nerve cell “controlling” a muscle cell for example:[2] The nerve cell does not know anything about muscle cells, let alone the specific muscel cell it is “attached to”. Likewise the muscle cell does not know anything about nerve cells, let a lone a specific nerve cell “attached to” it. Saying “the nerve cell is controlling the muscle cell” thus only makes sense when viewing both from the outside. “Control” is a concept of the whole, not of its parts. Control is created by wiring-up parts in a certain way. Both cells are mutually oblivious. Both just follow a contract. One produces Acetylcholine (ACh) as output, the other consumes ACh as input. Where the ACh is going, where it´s coming from neither cell cares about. Million years of evolution have led to this kind of division of labor. And million years of evolution have produced organism designs (DNA) which lead to the production of these different cell types (and many others) and also to their co-location. The result: the overall behavior of an organism. How and why this happened in nature is a mystery. For our software, though, it´s clear: functional and quality requirements needs to be fulfilled. So we as developers have to become “intelligent designers” of “software cells” which we put together to form a “software organism” which responds in satisfying ways to triggers from it´s environment. My bet is: If nature gets complex organisms working by following the PoMO, who are we to not apply this recipe for success to our much simpler “machines”? So my rule is: Wherever there is functionality to be delivered, because there is a clear Entry Point into software, design the functionality like nature would do it. Build it from mutually oblivious functional units. That´s what Flow Design is about. In that way it´s even universal, I´d say. Its notation can also be applied to biology: Never mind labeling the functional units with nouns. That´s ok in Flow Design. You´ll do that occassionally for functional units on a higher level of abstraction or when their purpose is close to hardware. Getting a cockroach to roam your bedroom takes 1,000,000 nerve cells (neurons). Getting the de-duplication program to do its job just takes 5 “software cells” (functional units). Both, though, follow the same basic principle. Translating functional units into code Moving from functional design to code is no rocket science. In fact it´s straightforward. There are two simple rules: Translate an input port to a function. Translate an output port either to a return statement in that function or to a function pointer visible to that function. The simplest translation of a functional unit is a function. That´s what you saw in the above example. Functions are mutually oblivious. That why Functional Programming likes them so much. It makes them composable. Which is the reason, nature works according to the PoMO. Let´s be clear about one thing: There is no dependency injection in nature. For all of an organism´s complexity no DI container is used. Behavior is the result of smooth cooperation between mutually oblivious building blocks. Functions will often be the adequate translation for the functional units in your designs. But not always. Take for example the case, where a processing step should not always produce an output. Maybe the purpose is to filter input. Here the functional unit consumes words and produces words. But it does not pass along every word flowing in. Some words are swallowed. Think of a spell checker. It probably should not check acronyms for correctness. There are too many of them. Or words with no more than two letters. Such words are called “stop words”. In the above picture the optionality of the output is signified by the astrisk outside the brackets. It means: Any number of (word) data items can flow from the functional unit for each input data item. It might be none or one or even more. This I call a stream of data. Such behavior cannot be translated into a function where output is generated with return. Because a function always needs to return a value. So the output port is translated into a function pointer or continuation which gets passed to the subroutine when called:[3]void filter_stop_words( string word, Action<string> onNoStopWord) { if (...check if not a stop word...) onNoStopWord(word); } If you want to be nitpicky you might call such a function pointer parameter an injection. And technically you´re right. Conceptually, though, it´s not an injection. Because the subroutine is not functionally dependent on the continuation. Firstly continuations are procedures, i.e. subroutines without a return type. Remember: Flow Design is about unidirectional data flow. Secondly the name of the formal parameter is chosen in a way as to not assume anything about downstream processing steps. onNoStopWord describes a situation (or event) within the functional unit only. Translating output ports into function pointers helps keeping functional units mutually oblivious in cases where output is optional or produced asynchronically. Either pass the function pointer to the function upon call. Or make it global by putting it on the encompassing class. Then it´s called an event. In C# that´s even an explicit feature.class Filter { public void filter_stop_words( string word) { if (...check if not a stop word...) onNoStopWord(word); } public event Action<string> onNoStopWord; } When to use a continuation and when to use an event dependens on how a functional unit is used in flows and how it´s packed together with others into classes. You´ll see examples further down the Flow Design road. Another example of 1D functional design Let´s see Flow Design once more in action using the visual notation. How about the famous word wrap kata? Robert C. Martin has posted a much cited solution including an extensive reasoning behind his TDD approach. So maybe you want to compare it to Flow Design. The function signature given is:string WordWrap(string text, int maxLineLength) {...} That´s not an Entry Point since we don´t see an application with an environment and users. Nevertheless it´s a function which is supposed to provide a certain functionality. The text passed in has to be reformatted. The input is a single line of arbitrary length consisting of words separated by spaces. The output should consist of one or more lines of a maximum length specified. If a word is longer than a the maximum line length it can be split in multiple parts each fitting in a line. Flow Design Let´s start by brainstorming the process to accomplish the feat of reformatting the text. What´s needed? Words need to be assembled into lines Words need to be extracted from the input text The resulting lines need to be assembled into the output text Words too long to fit in a line need to be split Does sound about right? I guess so. And it shows a kind of priority. Long words are a special case. So maybe there is a hint for an incremental design here. First let´s tackle “average words” (words not longer than a line). Here´s the Flow Design for this increment: The the first three bullet points turned into functional units with explicit data added. As the signature requires a text is transformed into another text. See the input of the first functional unit and the output of the last functional unit. In between no text flows, but words and lines. That´s good to see because thereby the domain is clearly represented in the design. The requirements are talking about words and lines and here they are. But note the asterisk! It´s not outside the brackets but inside. That means it´s not a stream of words or lines, but lists or sequences. For each text a sequence of words is output. For each sequence of words a sequence of lines is produced. The asterisk is used to abstract from the concrete implementation. Like with streams. Whether the list of words gets implemented as an array or an IEnumerable is not important during design. It´s an implementation detail. Does any processing step require further refinement? I don´t think so. They all look pretty “atomic” to me. And if not… I can always backtrack and refine a process step using functional design later once I´ve gained more insight into a sub-problem. Implementation The implementation is straightforward as you can imagine. The processing steps can all be translated into functions. Each can be tested easily and separately. Each has a focused responsibility. And the process flow becomes just a sequence of function calls: Easy to understand. It clearly states how word wrapping works - on a high level of abstraction. And it´s easy to evolve as you´ll see. Flow Design - Increment 2 So far only texts consisting of “average words” are wrapped correctly. Words not fitting in a line will result in lines too long. Wrapping long words is a feature of the requested functionality. Whether it´s there or not makes a difference to the user. To quickly get feedback I decided to first implement a solution without this feature. But now it´s time to add it to deliver the full scope. Fortunately Flow Design automatically leads to code following the Open Closed Principle (OCP). It´s easy to extend it - instead of changing well tested code. How´s that possible? Flow Design allows for extension of functionality by inserting functional units into the flow. That way existing functional units need not be changed. The data flow arrow between functional units is a natural extension point. No need to resort to the Strategy Pattern. No need to think ahead where extions might need to be made in the future. I just “phase in” the remaining processing step: Since neither Extract words nor Reformat know of their environment neither needs to be touched due to the “detour”. The new processing step accepts the output of the existing upstream step and produces data compatible with the existing downstream step. Implementation - Increment 2 A trivial implementation checking the assumption if this works does not do anything to split long words. The input is just passed on: Note how clean WordWrap() stays. The solution is easy to understand. A developer looking at this code sometime in the future, when a new feature needs to be build in, quickly sees how long words are dealt with. Compare this to Robert C. Martin´s solution:[4] How does this solution handle long words? Long words are not even part of the domain language present in the code. At least I need considerable time to understand the approach. Admittedly the Flow Design solution with the full implementation of long word splitting is longer than Robert C. Martin´s. At least it seems. Because his solution does not cover all the “word wrap situations” the Flow Design solution handles. Some lines would need to be added to be on par, I guess. But even then… Is a difference in LOC that important as long as it´s in the same ball park? I value understandability and openness for extension higher than saving on the last line of code. Simplicity is not just less code, it´s also clarity in design. But don´t take my word for it. Try Flow Design on larger problems and compare for yourself. What´s the easier, more straightforward way to clean code? And keep in mind: You ain´t seen all yet ;-) There´s more to Flow Design than described in this chapter. In closing I hope I was able to give you a impression of functional design that makes you hungry for more. To me it´s an inevitable step in software development. Jumping from requirements to code does not scale. And it leads to dirty code all to quickly. Some thought should be invested first. Where there is a clear Entry Point visible, it´s functionality should be designed using data flows. Because with data flows abstraction is possible. For more background on why that´s necessary read my blog article here. For now let me point out to you - if you haven´t already noticed - that Flow Design is a general purpose declarative language. It´s “programming by intention” (Shalloway et al.). Just write down how you think the solution should work on a high level of abstraction. This breaks down a large problem in smaller problems. And by following the PoMO the solutions to those smaller problems are independent of each other. So they are easy to test. Or you could even think about getting them implemented in parallel by different team members. Flow Design not only increases evolvability, but also helps becoming more productive. All team members can participate in functional design. This goes beyon collective code ownership. We´re talking collective design/architecture ownership. Because with Flow Design there is a common visual language to talk about functional design - which is the foundation for all other design activities.   PS: If you like what you read, consider getting my ebook “The Incremental Architekt´s Napkin”. It´s where I compile all the articles in this series for easier reading. I like the strictness of Function Programming - but I also find it quite hard to live by. And it certainly is not what millions of programmers are used to. Also to me it seems, the real world is full of state and side effects. So why give them such a bad image? That´s why functional design takes a more pragmatic approach. State and side effects are ok for processing steps - but be sure to follow the SRP. Don´t put too much of it into a single processing step. ? Image taken from www.physioweb.org ? My code samples are written in C#. C# sports typed function pointers called delegates. Action is such a function pointer type matching functions with signature void someName(T t). Other languages provide similar ways to work with functions as first class citizens - even Java now in version 8. I trust you find a way to map this detail of my translation to your favorite programming language. I know it works for Java, C++, Ruby, JavaScript, Python, Go. And if you´re using a Functional Programming language it´s of course a no brainer. ? Taken from his blog post “The Craftsman 62, The Dark Path”. ?

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