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• Excel macro to delete empty rows isn't stopping

  - by RocketGoal

  How do I make it stop after a certain amount of rows? I've taken a VBA course and my teacher explained how to delete empty rows. I'm now trying to put this in place but my macro isn't stopping. I thought I had limited it to 200 rows. I'm missing something important. Any pointers much appreciated. Sub RemoveRows() ' Remove rows from last blank cell Dim LastRow As Long Dim ISEmpty As Long 'Count how many records in the list. This is done so that the Do loop has a finish point. LastRow = Range("A200").End(xlUp).Row 'Start at the top of the list Range("A1").Select 'Loop until the end of the list Do While ActiveCell.Row < LastRow 'Assign number of non empty cells in the row ISEmpty = Application.CountA(ActiveCell.EntireRow) 'If ISEmpty = 0 then delete the row, if not move down a cell into the next row If ISEmpty = 0 Then ActiveCell.EntireRow.Delete Else ActiveCell.Offset(1, 0).Select End If Loop End Sub

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• Cocoa nextEventMatchingMask not receiving NSMouseMoved event

  - by Jonny

  Hello, I created a local event loop and showed up a borderless window (derived from NSPanel), I found in the event loop there's no NSMouseMoved event received, although I can receive Mouse button down/up events. What should I do to get the NSMouseMoved events? I found making the float window as key window can receive the NSMouseMoved events, but I don't want to change key window. And it appears this is possible, because I found after clicking the test App Icon in System Dock Bar, I can receive the mousemoved events, and the key window/mainwindow are unchanged. Here's the my test code: (Create a Cocoa App project names FloatWindowTest, and put a button to link it with the onClick: IBAction). Thanks in advance! -Jonny #import "FloatWindowTestAppDelegate.h" @interface FloatWindow : NSPanel @end @interface FloatWindowContentView : NSView @end @implementation FloatWindowTestAppDelegate @synthesize window; - (void)delayedAction:(id)sender { // What does this function do? // 1. create a float window // 2. create a local event loop // 3. print out the events got from nextEventMatchingMask. // 4. send it to float window. // What is the problem? // In local event loop, althrough the event mask has set NSMouseMovedMask // there's no mouse moved messages received. // FloatWindow* floatWindow = [[FloatWindow alloc] init]; NSEvent* event = [NSApp currentEvent]; NSPoint screenOrigin = [[self window] convertBaseToScreen:[event locationInWindow]]; [floatWindow setFrameTopLeftPoint:screenOrigin]; [floatWindow orderFront:nil]; //Making the float window as Key window will work, however //change active window is not anticipated. //[floatWindow makeKeyAndOrderFront:nil]; BOOL done = NO; while (!done) { NSAutoreleasePool* pool = [NSAutoreleasePool new]; NSUInteger eventMask = NSLeftMouseDownMask| NSLeftMouseUpMask| NSMouseMovedMask| NSMouseEnteredMask| NSMouseExitedMask| NSLeftMouseDraggedMask; NSEvent* event = [NSApp nextEventMatchingMask:eventMask untilDate:[NSDate distantFuture] inMode:NSDefaultRunLoopMode dequeue:YES]; //why I cannot get NSMouseMoved event?? NSLog(@"new event %@", [event description]); [floatWindow sendEvent:event]; [pool drain]; } [floatWindow release]; return; } -(IBAction)onClick:(id)sender { //Tried to postpone the local event loop //after return from button's mouse tracking loop. //but not fixes this problem. [[NSRunLoop currentRunLoop] performSelector:@selector(delayedAction:) target:self argument:nil order:0 modes:[NSArray arrayWithObject:NSDefaultRunLoopMode]]; } @end @implementation FloatWindow - (id)init { NSRect contentRect = NSMakeRect(200,300,200,300); self = [super initWithContentRect:contentRect styleMask:NSTitledWindowMask backing:NSBackingStoreBuffered defer:YES]; if (self) { [self setLevel:NSFloatingWindowLevel]; NSRect frameRect = [self frameRectForContentRect:contentRect]; NSView* view = [[[FloatWindowContentView alloc] initWithFrame:frameRect] autorelease]; [self setContentView:view]; [self setAcceptsMouseMovedEvents:YES]; [self setIgnoresMouseEvents:NO]; } return self; } - (BOOL)becomesKeyOnlyIfNeeded { return YES; } - (void)becomeMainWindow { NSLog(@"becomeMainWindow"); [super becomeMainWindow]; } - (void)becomeKeyWindow { NSLog(@"becomeKeyWindow"); [super becomeKeyWindow]; } @end @implementation FloatWindowContentView - (BOOL)acceptsFirstMouse:(NSEvent *)theEvent { return YES; } - (BOOL)acceptsFirstResponder { return YES; } - (id)initWithFrame:(NSRect)frameRect { self = [super initWithFrame:frameRect]; if (self) { NSTrackingArea* area; area = [[NSTrackingArea alloc] initWithRect:frameRect options:NSTrackingActiveAlways| NSTrackingMouseMoved| NSTrackingMouseEnteredAndExited owner:self userInfo:nil]; [self addTrackingArea:area]; [area release]; } return self; } - (void)drawRect:(NSRect)rect { [[NSColor redColor] set]; NSRectFill([self bounds]); } - (BOOL)becomeFirstResponder { NSLog(@"becomeFirstResponder"); return [super becomeFirstResponder]; } @end

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• Python/numpy tricky slicing problem

  - by daver

  Hi stack overflow, I have a problem with some numpy stuff. I need a numpy array to behave in an unusual manner by returning a slice as a view of the data I have sliced, not a copy. So heres an example of what I want to do: Say we have a simple array like this: a = array([1, 0, 0, 0]) I would like to update consecutive entries in the array (moving left to right) with the previous entry from the array, using syntax like this: a[1:] = a[0:3] This would get the following result: a = array([1, 1, 1, 1]) Or something like this: a[1:] = 2*a[:3] # a = [1,2,4,8] To illustrate further I want the following kind of behaviour: for i in range(len(a)): if i == 0 or i+1 == len(a): continue a[i+1] = a[i] Except I want the speed of numpy. The default behavior of numpy is to take a copy of the slice, so what I actually get is this: a = array([1, 1, 0, 0]) I already have this array as a subclass of the ndarray, so I can make further changes to it if need be, I just need the slice on the right hand side to be continually updated as it updates the slice on the left hand side. Am I dreaming or is this magic possible? Update: This is all because I am trying to use Gauss-Seidel iteration to solve a linear algebra problem, more or less. It is a special case involving harmonic functions, I was trying to avoid going into this because its really not necessary and likely to confuse things further, but here goes. The algorithm is this: while not converged: for i in range(len(u[:,0])): for j in range(len(u[0,:])): # skip over boundary entries, i,j == 0 or len(u) u[i,j] = 0.25*(u[i-1,j] + u[i+1,j] + u[i, j-1] + u[i,j+1]) Right? But you can do this two ways, Jacobi involves updating each element with its neighbours without considering updates you have already made until the while loop cycles, to do it in loops you would copy the array then update one array from the copied array. However Gauss-Seidel uses information you have already updated for each of the i-1 and j-1 entries, thus no need for a copy, the loop should essentially 'know' since the array has been re-evaluated after each single element update. That is to say, every time we call up an entry like u[i-1,j] or u[i,j-1] the information calculated in the previous loop will be there. I want to replace this slow and ugly nested loop situation with one nice clean line of code using numpy slicing: u[1:-1,1:-1] = 0.25(u[:-2,1:-1] + u[2:,1:-1] + u[1:-1,:-2] + u[1:-1,2:]) But the result is Jacobi iteration because when you take a slice: u[:,-2,1:-1] you copy the data, thus the slice is not aware of any updates made. Now numpy still loops right? Its not parallel its just a faster way to loop that looks like a parallel operation in python. I want to exploit this behaviour by sort of hacking numpy to return a pointer instead of a copy when I take a slice. Right? Then every time numpy loops, that slice will 'update' or really just replicate whatever happened in the update. To do this I need slices on both sides of the array to be pointers. Anyway if there is some really really clever person out there that awesome, but I've pretty much resigned myself to believing the only answer is to loop in C.

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• Input not cleared.

  - by SoulBeaver

  As the question says, for some reason my program is not flushing the input or using my variables in ways that I cannot identify at the moment. This is for a homework project that I've gone beyond what I had to do for it, now I just want the program to actually work :P Details to make the finding easier: The program executes flawlessly on the first run through. All throws work, only the proper values( n 0 ) are accepted and turned into binary. As soon as I enter my terminate input, the program goes into a loop and only asks for the termiante again like so: When I run this program on Netbeans on my Linux Laptop, the program crashes after I input the terminate value. On Visual C++ on Windows it goes into the loop like just described. In the code I have tried to clear every stream and initialze every variable new as the program restarts, but to no avail. I just can't see my mistake. I believe the error to lie in either the main function: int main( void ) { vector<int> store; int terminate = 1; do { int num = 0; string input = ""; if( cin.fail() ) { cin.clear(); cin.ignore( numeric_limits<streamsize>::max(), '\n' ); } cout << "Please enter a natural number." << endl; readLine( input, num ); cout << "\nThank you. Number is being processed..." << endl; workNum( num, store ); line; cout << "Go again? 0 to terminate." << endl; cin >> terminate // No checking yet, just want it to work! cin.clear(); }while( terminate ); cin.get(); return 0; } or in the function that reads the number: void readLine( string &input, int &num ) { int buf = 1; stringstream ss; vec_sz size; if( ss.fail() ) { ss.clear(); ss.ignore( numeric_limits<streamsize>::max(), '\n' ); } if( getline( cin, input ) ) { size = input.size(); for( int loop = 0; loop < size; ++loop ) if( isalpha( input[loop] ) ) throw domain_error( "Invalid Input." ); ss << input; ss >> buf; if( buf <= 0 ) throw domain_error( "Invalid Input." ); num = buf; ss.clear(); } }

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• Async networking + threading problem

  - by randallmeadows

  I kick off a network request, assuming no login credentials are required to talk to the destination server. If they are required, then I get an authentication challenge, at which point I display a view requesting said credentials from the user. When they are supplied, I restart the network request, using those credentials. That's all fine and dandy, as long as I only do one request at a time. But I'm not, typically. When both requests are kicked off, I get the first challenge, and present the prompt (using -presentModalViewController:). Then the 2nd challenge comes in. And I crash when it tries to display the 2nd prompt. I have the bulk of this wrapped in an @synchronized() block, but this has no effect because these delegate methods are all being called on the same (main) thread. The docs say the delegate methods are called on the same thread in which the connection was started. OK, no problem; I'll just write a method that I run on a background thread using -performSelectorInBackground: NSURLConnection *connection = [[NSURLConnection alloc] initWithRequest:request delegate:self startImmediately:NO]; [connections addObject:connection]; [self performSelectorInBackground:@selector(startConnection:) withObject:connection]; [connection release]; - (void)startConnection:(NSURLConnection *)connection { NSAutoreleasePool *pool = [NSAutoreleasePool new]; [connection scheduleInRunLoop:[NSRunLoop currentRunLoop] forMode:NSDefaultRunLoopMode]; [connection start]; [pool drain]; } which should put every network request, and its callbacks, on its own thread, and then my @synchronized() blocks will take effect. The docs for -initWithRequest:... state "Messages to the delegate will be sent on the thread that calls this method. By default, for the connection to work correctly the calling thread’s run loop must be operating in the default run loop mode." Ok, I'm doing that. They also state "If you pass NO [for startImmediately], you must schedule the connection in a run loop before starting it." OK, I'm doing that, too. Furthermore, the docs for NSRunLoop state "Each NSThread object, including the application’s main thread, has an NSRunLoop object automatically created for it as needed. If you need to access the current thread’s run loop, you do so with the class method currentRunLoop." I'm assuming this applies to the background thread created by the call -performSelectorInBackground... (which does appear to be the case, when I execute 'po [NSClassFromString(@"NSRunLoop") currentRunLoop]' in the -startConnection: method). The -startConnection: method is indeed being called. But after kicking off the connection, I now never get any callbacks on it. None of the -connectionDid… delegate methods. (I even tried explicitly starting the thread's run loop, but that made no difference; I've used threads like this before, and I've never had to start the run loop manually before--but I'm now grasping at straws...) I think I've come up with a workaround such that I only handle one request at a time, but it's kludgy and I'd like to do this the Right Way. But, what am I missing here? Thanks! randy

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• replaceAll() method using parameter from text file

  - by Herman Plani Ginting

  i have a collection of raw text in a table in database, i need to replace some words in this collection using a set of words. i put all the term to be replace and its substitutes in a text file as below min=admin lelet=lambat lemot=lambat nii=nih ntu=itu and so on. i have successfully initiate a variabel of File and Scanner to read the collection of the term and its substitutes. i loop all the dataset and save the raw text in a string in the same loop i loop all the term collection and save its row to a string name 'pattern', and split the pattern into two string named 'term' and 'replacer' in this loop i initiate a new string which its value is the string from the dataset modified by replaceAll(term,replacer) end loop for term collection then i insert the new string to another table in database end loop for dataset i do it manualy as below replaceAll("min","admin") and its works but its really something to code it manually for almost 2000 terms to be replace it. anyone ever face this kind of really something.. i really need a help now desperate :( package sentimenrepo; import javax.swing.*; import java.sql.*; import java.io.*; //import java.util.HashMap; import java.util.Scanner; //import java.util.Map; /** * * @author herman */ public class synonimReplaceV2 extends SwingWorker { protected Object doInBackground() throws Exception { new skripsisentimen.sentimenttwitter().setVisible(true); Integer row = 0; File synonimV2 = new File("synV2/catatan_kata_sinonim.txt"); String newTweet = ""; DB db = new DB(); Connection conn = db.dbConnect("jdbc:mysql://localhost:3306/tweet", "root", ""); try{ Statement select = conn.createStatement(); select.executeQuery("select * from synonimtweet"); ResultSet RS = select.getResultSet(); Scanner scSynV2 = new Scanner(synonimV2); while(RS.next()){ row++; String no = RS.getString("no"); String tweet = " "+ RS.getString("tweet"); String published = RS.getString("published"); String label = RS.getString("label"); clean2 cleanv2 = new clean2(); newTweet = cleanv2.cleanTweet(tweet); try{ Statement insert = conn.createStatement(); insert.executeUpdate("INSERT INTO synonimtweet_v2(no,tweet,published,label) values('" +no+"','"+newTweet+"','"+published+"','"+label+"')"); String current = skripsisentimen.sentimenttwitter.txtAreaResult.getText(); skripsisentimen.sentimenttwitter.txtAreaResult.setText(current+"\n"+row+"original : "+tweet+"\n"+newTweet+"\n______________________\n"); skripsisentimen.sentimenttwitter.lblStat.setText(row+" tweet read"); skripsisentimen.sentimenttwitter.txtAreaResult.setCaretPosition(skripsisentimen.sentimenttwitter.txtAreaResult.getText().length() - 1); }catch(Exception e){ skripsisentimen.sentimenttwitter.lblStat.setText(e.getMessage()); } skripsisentimen.sentimenttwitter.lblStat.setText(e.getMessage()); } }catch(Exception e){ skripsisentimen.sentimenttwitter.lblStat.setText(e.getMessage()); } return row; } class clean2{ public clean2(){} public String cleanTweet(String tweet){ File synonimV2 = new File("synV2/catatan_kata_sinonim.txt"); String pattern = ""; String term = ""; String replacer = ""; String newTweet=""; try{ Scanner scSynV2 = new Scanner(synonimV2); while(scSynV2.hasNext()){ pattern = scSynV2.next(); term = pattern.split("=")[0]; replacer = pattern.split("=")[1]; newTweet = tweet.replace(term, replacer); } }catch(Exception e){ e.printStackTrace(); } System.out.println(newTweet+"\n"+tweet); return newTweet; } } }

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• GLSL compile error when accessing an array with compile-time constant index

  - by Benlitz

  I have this shader that works well on my computer (using an ATI HD 5700). I have a loop iterating between two constant values, which is, afaik, acceptable in a glsl shader. I write stuff in two arrays in this loop. #define NB_POINT_LIGHT 2 ... varying vec3 vVertToLight[NB_POINT_LIGHT]; varying vec3 vVertToLightWS[NB_POINT_LIGHT]; ... void main() { ... for (int i = 0; i < NB_POINT_LIGHT; ++i) { if (bPointLightUse[i]) { vVertToLight[i] = ConvertToTangentSpace(ShPointLightData[i].Position - WorldPos.xyz); vVertToLightWS[i] = ShPointLightData[i].Position - WorldPos.xyz; } } ... } I tried my program on another computer equipped with an nVidia GTX 560 Ti, and it fails to compile my shader. I get the following errors (94 and 95 are the lines of the two affectations) when calling glLinkProgram: Vertex info ----------- 0(94) : error C5025: lvalue in assignment too complex 0(95) : error C5025: lvalue in assignment too complex I think my code is valid, I don't know if this comes from a compiler bug, a conversion of my shader to another format from the compiler (nvidia looks to convert it to CG), or if I just missed something. I already tried to remove the if (bPointLightUse[i]) statement and I still have the same error. However, if I just write this: vVertToLight[0] = ConvertToTangentSpace(ShPointLightData[0].Position - WorldPos.xyz); vVertToLightWS[0] = ShPointLightData[0].Position - WorldPos.xyz; vVertToLight[1] = ConvertToTangentSpace(ShPointLightData[1].Position - WorldPos.xyz); vVertToLightWS[1] = ShPointLightData[1].Position - WorldPos.xyz; Then I don't have the error anymore, but it's really unconvenient so I would prefer to keep something loop-based. Here is the more detailled config that works: Vendor: ATI Technologies Inc. Renderer: ATI Radeon HD 5700 Series Version: 4.1.10750 Compatibility Profile Context Shading Language version: 4.10 And here is the more detailed config that doesn't work (should also be compatibility profile, although not indicated): Vendor: NVIDIA Corporation Renderer: GeForce GTX 560 Ti/PCI/SSE2 Version: 4.1.0 Shading Language version: 4.10 NVIDIA via Cg compiler

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• Creating the concept of Time

  - by Jamie Dixon

  So I've reached the point in my exploration of gaming where I'd like to impliment the concept of time into my little demo I've been building. What are some common methodologies for creating the concept of time passing within a game? My thoughts so far: My game loop tendes to spend a fair bit of time sitting around waiting or user input so any time system will likely need to be run in a seperate thread. What I've currently done is create a BackgroundWorker passing in a method that contains a loop triggering every second. This is working fine and I can output information to the console from here etc. Inside this loop I have a DateTime object that is incrimented by 1 minute for every realtime second. (the game begins in the year 01/01/01) Is this a standard way of acheiving this result or are there more tried and tested methods? I'm also curious about how to go about performing time based actions (reducing player energy, moving entities around the game board, life/death etc). Thanks for any pointers or advice. I've searched around however I'm not familiar enough with the terms and so my searches are yeilding little result on this one.

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• Diagram that could explain a state machine's code?

  - by Incognito

  We have a lot of concepts in making diagrams like UML and flowcharting or just making up whatever boxes-and-arrows combination works at the time, but I'm looking at doing a visual diagram on something that's actually really complex. State machines like those that parse HTML or regular expressions tend to be very long and complicated bits of code. For example, this is the stateLoop for FireFox 9 beta. It's actually generated by another file, but this is the code that runs. How can I diagram something with the complexity of this in a way that explains flow of the code without taking it to a level where I draw every single line-of-code into it's own box on a flowchart? I don't want to draw "Invoke loop, then return" but I don't want to explain every last detail. What kind of graph is suitable to do this? Is there already something out there similar to this? Just an example of how to do this without going overboard in complexity or too-high-level is really what I want. If you don't feel like looking at the code, basically it's 70 different state flags that could occur, inside an infinite loop that exists to a label based on some conditions, each flag has it's own infinite loop that exists to a label somewhere, and each of those loops has checks for different types of chars, which then runs off into various other methods.

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• How to Handle frame rates and synchronizing screen repaints

  - by David Kroukamp

  I would first off say sorry if the title is worded incorrectly. Okay now let me give the scenario I'm creating a 2 player fighting game, An average battle will include a Map (moving/still) and 2 characters (which are rendered by redrawing a varying amount of sprites one after the other). Now at the moment I have a single game loop limiting me to a set number of frames per second (using Java): Timer timer = new Timer(0, new AbstractAction() { @Override public void actionPerformed(ActionEvent e) { long beginTime; //The time when the cycle begun long timeDiff; //The time it took for the cycle to execute int sleepTime; //ms to sleep (< 0 if we're behind) int fps = 1000 / 40; beginTime = System.nanoTime() / 1000000; //execute loop to update check collisions and draw gameLoop(); //Calculate how long did the cycle take timeDiff = System.nanoTime() / 1000000 - beginTime; //Calculate sleep time sleepTime = fps - (int) (timeDiff); if (sleepTime > 0) {//If sleepTime > 0 we're OK ((Timer)e.getSource()).setDelay(sleepTime); } } }); timer.start(); in gameLoop() characters are drawn to the screen ( a character holds an array of images which consists of their current sprites) every gameLoop() call will change the characters current sprite to the next and loop if the end is reached. But as you can imagine if a sprite is only 3 images in length than calling gameLoop() 40 times will cause the characters movement to be drawn 40/3=13 times. This causes a few minor anomilies in the sprited for some charcters So my question is how would I go about delivering a set amount of frames per second in when I have 2 characters on screen with varying amount of sprites?

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• What is the best practice for when to check if something needs to be done?

  - by changokun

  Let's say I have a function that does x. I pass it a variable, and if the variable is not null, it does some action. And I have an array of variables and I'm going to run this function on each one. Inside the function, it seems like a good practice is to check if the argument is null before proceeding. A null argument is not an error, it just causes an early return. I could loop through the array and pass each value to the function, and the function will work great. Is there any value to checking if the var is null and only calling the function if it is not null during the loop? This doubles up on the checking for null, but: Is there any gained value? Is there any gain on not calling a function? Any readability gain on the loop in the parent code? For the sake of my question, let's assume that checking for null will always be the case. I can see how checking for some object property might change over time, which makes the first check a bad idea. Pseudo code example: for(thing in array) { x(thing) } Versus: for(thing in array) { if(thing not null) x(thing) } If there are language-specific concerns, I'm a web developer working in PHP and JavaScript.

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• Any Practical Alternative to the Signals + Slots model for GUI Programming?

  - by IntermediateHacker

  The majority of GUI Toolkits nowadays use the Signals + Slots model. It was Qt and GTK+, if I am not wrong, who pioneered it. You know, the widgets or graphical objects (sometimes even ones that aren't displayed) send signals to the main-loop handler. The main-loop handler then calls the events, callbacks or slots assigned for that widget / graphical object. There are usually default (and in most cases virtual) event-handlers already provided by the toolkit for handling all pre-defined signals, therefore, unlike previous designs where the developer had to write the entire main-loop and handler for each and every message himself (think WINAPI), the developer only has to worry about the signals he needs to implement new functionality on. Now this design is being used in most modern toolkits as far as I know. There are Qt, GTK+, FLTK etc. There is Java Swing. C# even has a language feature for it ( events and delegates ), and Windows Forms has been developed on this design. In fact, over the last decade, this design for GUI programming has become a kind of an unwritten standard. Since it increases productivity and provides greater abstraction. However, my question is: Is there any alternative design, that is parallel or practical for modern GUI programming? i.e Is the Signals + Slots design, the only practical one in town? Is it feasible to do GUI Programming with any other design? Are any modern (preferably successful and popular) GUI toolkits built on an alternative design?

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• Implementing the transport layer for a SIP UAC

  - by Jonathan Henson

  I have a somewhat simple, but specific, question about implementing the transport layer for a SIP UAC. Do I expect the response to a request on the same socket that I sent the request on, or do I let the UDP or TCP listener pick up the response and then route it to the correct transaction from there? The RFC does not seem to say anything on the matter. It seems that especially using UDP, which is connection-less, that I should just let the listeners pick up the response, but that seems sort of counter intuitive. Particularly, I have seen plenty of UAC implementations which do not depend on having a Listener in the transport layer. Also, most implementations I have looked at do not have the UAS receiving loop responding on the socket at all. This would tend to indicate that the client should not be expecting a reply on the socket that it sent the request on. For clarification: Suppose my transport layer consists of the following elements: TCPClient (Sends Requests for a UAC via TCP) UDPClient (Sends Requests for a UAC vid UDP) TCPSever (Loop receiving Requests and dispatching to transaction layer via TCP) UDPServer (Loop receiving Requests and dispatching to transaction layer via UDP) Obviously, the *Client sends my Requests. The question is, what receives the Response? The *Client waiting on a recv or recvfrom call on the socket it used to send the request, or the *Server? Conversely, the *Server receives my requests, What sends the Response? The *Client? doesn't this break the roles of each member a bit?

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• How to parse JSON data from web more faster [closed]

  - by Kaidul Islam Sazal

  I have json inventory inventory.json on the server like this: [ { "body" : "SUV", "color" : { "ext" : "White diamond pearl", "int" : "Taupe" }, "id" : "276181", "make" : "Acura", "miles" : 35949, "model" : "RDX", "pic" : [ { "full" : "http://images1.dealercp.com/90961/000JNBD/001_0292.jpg" } ], "power" : { "drive" : "Front wheel drive", "eng" : "2.3L DOHC PGM-FI 16-VALVE", "trans" : "Automatic" }, "price" : { "net" : 29488 }, "stock" : "6942", "trim" : "AWD 4dr Tech Pkg SUV", "vin" : "5J8TB2H53BA000334", "year" : 2011 }, { "body" : "Sedan", "color" : { "ext" : "Premium white pearl", "int" : "Taupe" }, "id" : "275622", "make" : "Acura", "miles" : 40923, "model" : "TSX", "pic" : [ { "full" : "http://images1.dealercp.com/90961/000JMC6/001_1765.jpg" } ], "power" : { "drive" : "Front wheel drive", "eng" : "2.4L L4 MPI DOHC 16V", "trans" : "Automatic" }, "price" : { "net" : 22288 }, "stock" : "6945", "trim" : "4dr Sdn I4 Auto Sedan", "vin" : "JH4CU2F66AC011933", "year" : 2010 } ] here are two index, There are almost 5000 index like this. I parsed this json like this: var url = "inventory/inventory.json"; $.getJSON(url, function(data){ $.each(data, function(index, item){ //straight-forward loop if(item.year == 2012) { $('#desc').append(item.make + ' ' + item.model + ' ' + '<br/>' + item.price.net + '<br/>' + item.pic[0].full); } }); }); This is working fine.But the problem is that, this searching and fetching process is little bit slow as there are 5000 indexes already and it's increasing day by day. It seems that, it is a straight-forward loop to parse the data and a normal brute-force method. Now I want to know if there any time efiicient way to parse more faster.Any faster method to parse instead of straight-forward loop ?

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• Are long methods always bad?

  - by wobbily_col

  So looking around earlier I noticed some comments about long methods being bad practice. I am not sure I always agree that long methods are bad (and would like opinions from others). For example I have some Django views that do a bit of processing of the objects before sending them to the view, a long method being 350 lines of code. I have my code written so that it deals with the paramaters - sorting / filtering the queryset, then bit by bit does some processing on the objects my query has returned. So the processing is mainly conditional aggregation, that has complex enough rules it can't easily be done in the database, so I have some variables declared outside the main loop then get altered during the loop. varaible_1 = 0 variable_2 = 0 for object in queryset : if object.condition_condition_a and variable_2 > 0 : variable 1+= 1 ..... ... . more conditions to alter the variables return queryset, and context So according to the theory I should factor out all the code into smaller methods, so That I have the view method as being maximum one page long. However having worked on various code bases in the past, I sometimes find it makes the code less readable, when you need to constantly jump from one method to the next figuring out all the parts of it, while keeping the outermost method in your head. I find that having a long method that is well formatted, you can see the logic more easily, as it isn't getting hidden away in inner methods. I could factor out the code into smaller methods, but often there is is an inner loop being used for two or three things, so it would result in more complex code, or methods that don't do one thing but two or three (alternatively I could repeat inner loops for each task, but then there will be a performance hit). So is there a case that long methods are not always bad? Is there always a case for writing methods, when they will only be used in one place?

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• How to tell your boss that he's a bad programmer? [closed]

  - by Doe

  Possible Duplicate: How to tell your boss that his programming style is really bad? There was a question about the boss having a bad programming style (weird booleans, empty loops, etc.) Having a bad/weird style does not imply being a bad programmer, but my situation is different. My boss outputs some really nasty code for the project, on which we are working together (just two of us). Examples: functions that span over several screens (big screens - 1900 x 1200) Deeply nested Conditional and Loop statements (up to 10 levels!!) Too much static variables, singletons, and both (singleton class with all the methods and members also static) Sometimes the code committed to the version control system does not even compile! Copy-Paste code instead of separating it into an independent function. Fail all the deadlines. "This's [C#|Java|Python] it shouldn't be efficient, that's why we loop all over the haystack to find the needle." "This's C/C++, it's fast enough to loop all over the haystack to find the needle." There is much more to mention... But the worst is that I have to redo much of the stuff he does, my code, which I try to keep clean is often polluted with above-mentioned atrocities. He's reaching 30 soon, so all his skills are established, and I don't even know if it's possible to change something. I like the project, but sometimes I just want to quit...

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• Active Directory and Apple's Workgroup Manager

  - by qbn

  I thought I'd share my experiences here. I work for a small business with only ~20 users. I wanted the ability to use managed client preferences to assign things like the software update server. Basically the ability to manage my Macs easily and in a native way. At first I tried the magic triangle solution, but I found this to be very complicated. Not only does it require a Mac OS X Server, but it gives you two points of failure. Additionally each Mac workstation must be bound to both servers. Eventually I sucked it up and went with the schema changes documented here. I was hesitant at first, because the instructions require a lot of manual work. However it was fairly basic and only took me about an hour and a half. Below you'll find the schema changes file that was a result of my work. I followed the instructions exactly and double checked everything, after six months of having this in place things have been running great. Too good to not share. I hope I save someone a couple of hours. # ================================================================== # # This file should be imported with the following command: # ldifde -i -u -f Apple AD Schema Changes.ldf -s server:port -b username domain password -j . -c "cn=Configuration,dc=X" #configurationNamingContext # LDIFDE.EXE from AD/AM V1.0 or above must be used. # This LDIF file should be imported into AD or AD/AM. It may not work for other directories. # # ================================================================== # ================================================================== # Attributes # ================================================================== # Attribute: apple-category dn: cn=apple-category,cn=Schema,cn=Configuration,dc=X changetype: ntdsschemaadd objectClass: attributeSchema attributeId: 1.3.6.1.4.1.63.1000.1.1.1.10.4 ldapDisplayName: apple-category attributeSyntax: 2.5.5.12 adminDescription: Category for the computer or neighborhood oMSyntax: 64 systemOnly: FALSE # Attribute: apple-computeralias dn: cn=apple-computeralias,cn=Schema,cn=Configuration,dc=X changetype: ntdsschemaadd objectClass: attributeSchema attributeId: 1.3.6.1.4.1.63.1000.1.1.1.20.3 ldapDisplayName: apple-computeralias attributeSyntax: 2.5.5.12 adminDescription: XML plist referring to a computer record oMSyntax: 64 systemOnly: FALSE # Attribute: apple-computer-list-groups dn: cn=apple-computer-list-groups,cn=Schema,cn=Configuration,dc=X changetype: ntdsschemaadd objectClass: attributeSchema attributeId: 1.3.6.1.4.1.63.1000.1.1.1.11.4 ldapDisplayName: apple-computer-list-groups attributeSyntax: 2.5.5.12 adminDescription: groups oMSyntax: 64 systemOnly: FALSE # Attribute: apple-computers dn: cn=apple-computers,cn=Schema,cn=Configuration,dc=X changetype: ntdsschemaadd objectClass: attributeSchema attributeId: 1.3.6.1.4.1.63.1000.1.1.1.11.3 ldapDisplayName: apple-computers attributeSyntax: 2.5.5.12 adminDescription: computers oMSyntax: 64 systemOnly: FALSE # Attribute: apple-data-stamp dn: cn=apple-data-stamp,cn=Schema,cn=Configuration,dc=X changetype: ntdsschemaadd objectClass: attributeSchema attributeId: 1.3.6.1.4.1.63.1000.1.1.1.12.2 ldapDisplayName: apple-data-stamp attributeSyntax: 2.5.5.5 adminDescription: data stamp oMSyntax: 22 isSingleValued: TRUE systemOnly: FALSE # Attribute: apple-dns-domain dn: cn=apple-dns-domain,cn=Schema,cn=Configuration,dc=X changetype: ntdsschemaadd objectClass: attributeSchema attributeId: 1.3.6.1.4.1.63.1000.1.1.1.18.1 ldapDisplayName: apple-dns-domain attributeSyntax: 2.5.5.12 adminDescription: DNS domain oMSyntax: 64 systemOnly: FALSE # Attribute: apple-dnsname dn: cn=apple-dnsname,cn=Schema,cn=Configuration,dc=X changetype: ntdsschemaadd objectClass: attributeSchema attributeId: 1.3.6.1.4.1.63.1000.1.1.1.19.4 ldapDisplayName: apple-dnsname attributeSyntax: 2.5.5.12 adminDescription: DNS name oMSyntax: 64 systemOnly: FALSE # Attribute: apple-dns-nameserver dn: cn=apple-dns-nameserver,cn=Schema,cn=Configuration,dc=X changetype: ntdsschemaadd objectClass: attributeSchema attributeId: 1.3.6.1.4.1.63.1000.1.1.1.18.2 ldapDisplayName: apple-dns-nameserver attributeSyntax: 2.5.5.12 adminDescription: DNS name server list oMSyntax: 64 systemOnly: FALSE # Attribute: apple-group-homeowner dn: cn=apple-group-homeowner,cn=Schema,cn=Configuration,dc=X changetype: ntdsschemaadd objectClass: attributeSchema attributeId: 1.3.6.1.4.1.63.1000.1.1.1.14.2 ldapDisplayName: apple-group-homeowner attributeSyntax: 2.5.5.5 adminDescription: group home owner settings oMSyntax: 22 isSingleValued: TRUE systemOnly: FALSE # Attribute: apple-group-homeurl dn: cn=apple-group-homeurl,cn=Schema,cn=Configuration,dc=X changetype: ntdsschemaadd objectClass: attributeSchema attributeId: 1.3.6.1.4.1.63.1000.1.1.1.14.1 ldapDisplayName: apple-group-homeurl attributeSyntax: 2.5.5.5 adminDescription: group home url oMSyntax: 22 isSingleValued: TRUE systemOnly: FALSE # Attribute: apple-imhandle dn: cn=apple-imhandle,cn=Schema,cn=Configuration,dc=X changetype: ntdsschemaadd objectClass: attributeSchema attributeId: 1.3.6.1.4.1.63.1000.1.1.1.1.21 ldapDisplayName: apple-imhandle attributeSyntax: 2.5.5.12 adminDescription: IM handle (service:account name) oMSyntax: 64 systemOnly: FALSE # Attribute: apple-keyword dn: cn=apple-keyword,cn=Schema,cn=Configuration,dc=X changetype: ntdsschemaadd objectClass: attributeSchema attributeId: 1.3.6.1.4.1.63.1000.1.1.1.1.19 ldapDisplayName: apple-keyword attributeSyntax: 2.5.5.12 adminDescription: keywords oMSyntax: 64 systemOnly: FALSE # Attribute: apple-mcxflags dn: cn=apple-mcxflags,cn=Schema,cn=Configuration,dc=X changetype: ntdsschemaadd objectClass: attributeSchema attributeId: 1.3.6.1.4.1.63.1000.1.1.1.1.10 ldapDisplayName: apple-mcxflags attributeSyntax: 2.5.5.12 adminDescription: mcx flags oMSyntax: 64 isSingleValued: TRUE systemOnly: FALSE # Attribute: apple-mcxsettings dn: cn=apple-mcxsettings,cn=Schema,cn=Configuration,dc=X changetype: ntdsschemaadd objectClass: attributeSchema attributeId: 1.3.6.1.4.1.63.1000.1.1.1.1.16 ldapDisplayName: apple-mcxsettings attributeSyntax: 2.5.5.12 adminDescription: mcx settings oMSyntax: 64 systemOnly: FALSE # Attribute: apple-neighborhoodalias dn: cn=apple-neighborhoodalias,cn=Schema,cn=Configuration,dc=X changetype: ntdsschemaadd objectClass: attributeSchema attributeId: 1.3.6.1.4.1.63.1000.1.1.1.20.2 ldapDisplayName: apple-neighborhoodalias attributeSyntax: 2.5.5.12 adminDescription: XML plist referring to another neighborhood record oMSyntax: 64 systemOnly: FALSE # Attribute: apple-networkview dn: cn=apple-networkview,cn=Schema,cn=Configuration,dc=X changetype: ntdsschemaadd objectClass: attributeSchema attributeId: 1.3.6.1.4.1.63.1000.1.1.1.10.3 ldapDisplayName: apple-networkview attributeSyntax: 2.5.5.12 adminDescription: Network view for the computer oMSyntax: 64 systemOnly: FALSE # Attribute: apple-nodepathxml dn: cn=apple-nodepathxml,cn=Schema,cn=Configuration,dc=X changetype: ntdsschemaadd objectClass: attributeSchema attributeId: 1.3.6.1.4.1.63.1000.1.1.1.20.1 ldapDisplayName: apple-nodepathxml attributeSyntax: 2.5.5.12 adminDescription: XML plist of directory node path oMSyntax: 64 systemOnly: FALSE # Attribute: apple-service-location dn: cn=apple-service-location,cn=Schema,cn=Configuration,dc=X changetype: ntdsschemaadd objectClass: attributeSchema attributeId: 1.3.6.1.4.1.63.1000.1.1.1.19.5 ldapDisplayName: apple-service-location attributeSyntax: 2.5.5.12 adminDescription: Service location oMSyntax: 64 systemOnly: FALSE # Attribute: apple-service-port dn: cn=apple-service-port,cn=Schema,cn=Configuration,dc=X changetype: ntdsschemaadd objectClass: attributeSchema attributeId: 1.3.6.1.4.1.63.1000.1.1.1.19.3 ldapDisplayName: apple-service-port attributeSyntax: 2.5.5.9 adminDescription: Service port number oMSyntax: 2 systemOnly: FALSE # Attribute: apple-service-type dn: cn=apple-service-type,cn=Schema,cn=Configuration,dc=X changetype: ntdsschemaadd objectClass: attributeSchema attributeId: 1.3.6.1.4.1.63.1000.1.1.1.19.1 ldapDisplayName: apple-service-type attributeSyntax: 2.5.5.5 adminDescription: type of service oMSyntax: 22 systemOnly: FALSE # Attribute: apple-service-url dn: cn=apple-service-url,cn=Schema,cn=Configuration,dc=X changetype: ntdsschemaadd objectClass: attributeSchema attributeId: 1.3.6.1.4.1.63.1000.1.1.1.19.2 ldapDisplayName: apple-service-url attributeSyntax: 2.5.5.5 adminDescription: URL of service oMSyntax: 22 systemOnly: FALSE # Attribute: apple-user-authenticationhint dn: cn=apple-user-authenticationhint,cn=Schema,cn=Configuration,dc=X changetype: ntdsschemaadd objectClass: attributeSchema attributeId: 1.3.6.1.4.1.63.1000.1.1.1.1.15 ldapDisplayName: apple-user-authenticationhint attributeSyntax: 2.5.5.12 adminDescription: password hint oMSyntax: 64 isSingleValued: TRUE systemOnly: FALSE # Attribute: apple-user-class dn: cn=apple-user-class,cn=Schema,cn=Configuration,dc=X changetype: ntdsschemaadd objectClass: attributeSchema attributeId: 1.3.6.1.4.1.63.1000.1.1.1.1.7 ldapDisplayName: apple-user-class attributeSyntax: 2.5.5.5 adminDescription: user class oMSyntax: 22 isSingleValued: TRUE systemOnly: FALSE # Attribute: apple-user-homequota dn: cn=apple-user-homequota,cn=Schema,cn=Configuration,dc=X changetype: ntdsschemaadd objectClass: attributeSchema attributeId: 1.3.6.1.4.1.63.1000.1.1.1.1.8 ldapDisplayName: apple-user-homequota attributeSyntax: 2.5.5.5 adminDescription: home directory quota oMSyntax: 22 isSingleValued: TRUE systemOnly: FALSE # Attribute: apple-user-homesoftquota dn: cn=apple-user-homesoftquota,cn=Schema,cn=Configuration,dc=X changetype: ntdsschemaadd objectClass: attributeSchema attributeId: 1.3.6.1.4.1.63.1000.1.1.1.1.17 ldapDisplayName: apple-user-homesoftquota attributeSyntax: 2.5.5.5 adminDescription: home directory soft quota oMSyntax: 22 isSingleValued: TRUE systemOnly: FALSE # Attribute: apple-user-homeurl dn: cn=apple-user-homeurl,cn=Schema,cn=Configuration,dc=X changetype: ntdsschemaadd objectClass: attributeSchema attributeId: 1.3.6.1.4.1.63.1000.1.1.1.1.6 ldapDisplayName: apple-user-homeurl attributeSyntax: 2.5.5.5 adminDescription: home directory URL oMSyntax: 22 isSingleValued: TRUE systemOnly: FALSE # Attribute: apple-user-mailattribute dn: cn=apple-user-mailattribute,cn=Schema,cn=Configuration,dc=X changetype: ntdsschemaadd objectClass: attributeSchema attributeId: 1.3.6.1.4.1.63.1000.1.1.1.1.9 ldapDisplayName: apple-user-mailattribute attributeSyntax: 2.5.5.12 adminDescription: mail attribute oMSyntax: 64 isSingleValued: TRUE systemOnly: FALSE # Attribute: apple-user-picture dn: cn=apple-user-picture,cn=Schema,cn=Configuration,dc=X changetype: ntdsschemaadd objectClass: attributeSchema attributeId: 1.3.6.1.4.1.63.1000.1.1.1.1.12 ldapDisplayName: apple-user-picture attributeSyntax: 2.5.5.12 adminDescription: picture oMSyntax: 64 isSingleValued: TRUE systemOnly: FALSE # Attribute: apple-user-printattribute dn: cn=apple-user-printattribute,cn=Schema,cn=Configuration,dc=X changetype: ntdsschemaadd objectClass: attributeSchema attributeId: 1.3.6.1.4.1.63.1000.1.1.1.1.13 ldapDisplayName: apple-user-printattribute attributeSyntax: 2.5.5.12 adminDescription: print attribute oMSyntax: 64 isSingleValued: TRUE systemOnly: FALSE # Attribute: apple-webloguri dn: cn=apple-webloguri,cn=Schema,cn=Configuration,dc=X changetype: ntdsschemaadd objectClass: attributeSchema attributeId: 1.3.6.1.4.1.63.1000.1.1.1.1.22 ldapDisplayName: apple-webloguri attributeSyntax: 2.5.5.12 adminDescription: Weblog URI oMSyntax: 64 isSingleValued: TRUE systemOnly: FALSE # Attribute: apple-xmlplist dn: cn=apple-xmlplist,cn=Schema,cn=Configuration,dc=X changetype: ntdsschemaadd objectClass: attributeSchema attributeId: 1.3.6.1.4.1.63.1000.1.1.1.17.1 ldapDisplayName: apple-xmlplist attributeSyntax: 2.5.5.12 adminDescription: XML plist data oMSyntax: 64 isSingleValued: TRUE systemOnly: FALSE # Attribute: ipHostNumber dn: cn=ipHostNumber,cn=Schema,cn=Configuration,dc=X changetype: ntdsschemaadd objectClass: attributeSchema attributeId: 1.3.6.1.1.1.1.19 ldapDisplayName: ipHostNumber attributeSyntax: 2.5.5.5 adminDescription: IP address oMSyntax: 22 systemOnly: FALSE rangeUpper: 128 # Attribute: macAddress dn: cn=macAddress,cn=Schema,cn=Configuration,dc=X changetype: ntdsschemaadd objectClass: attributeSchema attributeId: 1.3.6.1.1.1.1.22 ldapDisplayName: macAddress attributeSyntax: 2.5.5.5 adminDescription: MAC address oMSyntax: 22 systemOnly: FALSE rangeUpper: 128 # Attribute: mountDirectory dn: cn=apple-mountDirectory,cn=Schema,cn=Configuration,dc=X changetype: ntdsschemaadd objectClass: attributeSchema attributeId: 1.3.6.1.4.1.63.1000.1.1.1.8.1 ldapDisplayName: mountDirectory attributeSyntax: 2.5.5.12 adminDescription: mount path oMSyntax: 64 isSingleValued: TRUE systemOnly: FALSE # Attribute: mountDumpFrequency dn: cn=apple-mountDumpFrequency,cn=Schema,cn=Configuration,dc=X changetype: ntdsschemaadd objectClass: attributeSchema attributeId: 1.3.6.1.4.1.63.1000.1.1.1.8.4 ldapDisplayName: mountDumpFrequency attributeSyntax: 2.5.5.5 adminDescription: mount dump frequency oMSyntax: 22 isSingleValued: TRUE systemOnly: FALSE # Attribute: mountOption dn: cn=apple-mountOption,cn=Schema,cn=Configuration,dc=X changetype: ntdsschemaadd objectClass: attributeSchema attributeId: 1.3.6.1.4.1.63.1000.1.1.1.8.3 ldapDisplayName: mountOption attributeSyntax: 2.5.5.5 adminDescription: mount options oMSyntax: 22 systemOnly: FALSE # Attribute: mountPassNo dn: cn=apple-mountPassNo,cn=Schema,cn=Configuration,dc=X changetype: ntdsschemaadd objectClass: attributeSchema attributeId: 1.3.6.1.4.1.63.1000.1.1.1.8.5 ldapDisplayName: mountPassNo attributeSyntax: 2.5.5.5 adminDescription: mount passno oMSyntax: 22 isSingleValued: TRUE systemOnly: FALSE # Attribute: mountType dn: cn=apple-mountType,cn=Schema,cn=Configuration,dc=X changetype: ntdsschemaadd objectClass: attributeSchema attributeId: 1.3.6.1.4.1.63.1000.1.1.1.8.2 ldapDisplayName: mountType attributeSyntax: 2.5.5.5 adminDescription: mount VFS type oMSyntax: 22 isSingleValued: TRUE systemOnly: FALSE # Attribute: ttl dn: cn=ttl,cn=Schema,cn=Configuration,dc=X changetype: ntdsschemaadd objectClass: attributeSchema attributeId: 1.3.6.1.4.1.250.1.60 ldapDisplayName: ttl attributeSyntax: 2.5.5.9 oMSyntax: 2 isSingleValued: TRUE systemOnly: FALSE dn: changetype: modify add: schemaUpdateNow schemaUpdateNow: 1 - # ================================================================== # Classes # ================================================================== # Class: apple-computer dn: cn=apple-computer,cn=Schema,cn=Configuration,dc=X changetype: ntdsschemaadd objectClass: classSchema governsID: 1.3.6.1.4.1.63.1000.1.1.2.10 ldapDisplayName: apple-computer adminDescription: computer objectClassCategory: 3 # subclassOf: top subclassOf: 2.5.6.0 # rdnAttId: cn rdnAttId: 2.5.4.3 # mayContain: apple-category mayContain: 1.3.6.1.4.1.63.1000.1.1.1.10.4 # mayContain: apple-computer-list-groups mayContain: 1.3.6.1.4.1.63.1000.1.1.1.11.4 # mayContain: apple-keyword mayContain: 1.3.6.1.4.1.63.1000.1.1.1.1.19 # mayContain: apple-mcxflags mayContain: 1.3.6.1.4.1.63.1000.1.1.1.1.10 # mayContain: apple-mcxsettings mayContain: 1.3.6.1.4.1.63.1000.1.1.1.1.16 # mayContain: apple-networkview mayContain: 1.3.6.1.4.1.63.1000.1.1.1.10.3 # mayContain: apple-service-url mayContain: 1.3.6.1.4.1.63.1000.1.1.1.19.2 # mayContain: apple-xmlplist mayContain: 1.3.6.1.4.1.63.1000.1.1.1.17.1 # mayContain: macAddress mayContain: 1.3.6.1.1.1.1.22 # mayContain: ttl mayContain: 1.3.6.1.4.1.250.1.60 # Class: apple-computer-list dn: cn=apple-computer-list,cn=Schema,cn=Configuration,dc=X changetype: ntdsschemaadd objectClass: classSchema governsID: 1.3.6.1.4.1.63.1000.1.1.2.11 ldapDisplayName: apple-computer-list adminDescription: computer list objectClassCategory: 1 # subclassOf: top subclassOf: 2.5.6.0 # rdnAttId: cn rdnAttId: 2.5.4.3 # mayContain: apple-computer-list-groups mayContain: 1.3.6.1.4.1.63.1000.1.1.1.11.4 # mayContain: apple-computers mayContain: 1.3.6.1.4.1.63.1000.1.1.1.11.3 # mayContain: apple-keyword mayContain: 1.3.6.1.4.1.63.1000.1.1.1.1.19 # mayContain: apple-mcxflags mayContain: 1.3.6.1.4.1.63.1000.1.1.1.1.10 # mayContain: apple-mcxsettings mayContain: 1.3.6.1.4.1.63.1000.1.1.1.1.16 possSuperiors: organizationalUnit possSuperiors: container # Class: apple-configuration dn: cn=apple-configuration,cn=Schema,cn=Configuration,dc=X changetype: ntdsschemaadd objectClass: classSchema governsID: 1.3.6.1.4.1.63.1000.1.1.2.12 ldapDisplayName: apple-configuration adminDescription: configuration objectClassCategory: 3 # subclassOf: top subclassOf: 2.5.6.0 # rdnAttId: cn rdnAttId: 2.5.4.3 # mayContain: apple-data-stamp mayContain: 1.3.6.1.4.1.63.1000.1.1.1.12.2 # mayContain: apple-keyword mayContain: 1.3.6.1.4.1.63.1000.1.1.1.1.19 # mayContain: apple-xmlplist mayContain: 1.3.6.1.4.1.63.1000.1.1.1.17.1 # mayContain: ttl mayContain: 1.3.6.1.4.1.250.1.60 possSuperiors: organizationalUnit possSuperiors: container # Class: apple-group dn: cn=apple-group,cn=Schema,cn=Configuration,dc=X changetype: ntdsschemaadd objectClass: classSchema governsID: 1.3.6.1.4.1.63.1000.1.1.2.14 ldapDisplayName: apple-group adminDescription: group account objectClassCategory: 3 # subclassOf: top subclassOf: 2.5.6.0 # rdnAttId: cn rdnAttId: 2.5.4.3 # mayContain: apple-group-homeowner mayContain: 1.3.6.1.4.1.63.1000.1.1.1.14.2 # mayContain: apple-group-homeurl mayContain: 1.3.6.1.4.1.63.1000.1.1.1.14.1 # mayContain: apple-keyword mayContain: 1.3.6.1.4.1.63.1000.1.1.1.1.19 # mayContain: apple-mcxflags mayContain: 1.3.6.1.4.1.63.1000.1.1.1.1.10 # mayContain: apple-mcxsettings mayContain: 1.3.6.1.4.1.63.1000.1.1.1.1.16 # mayContain: apple-user-picture mayContain: 1.3.6.1.4.1.63.1000.1.1.1.1.12 # mayContain: ttl mayContain: 1.3.6.1.4.1.250.1.60 # Class: apple-location dn: cn=apple-location,cn=Schema,cn=Configuration,dc=X changetype: ntdsschemaadd objectClass: classSchema governsID: 1.3.6.1.4.1.63.1000.1.1.2.18 ldapDisplayName: apple-location objectClassCategory: 1 # subclassOf: top subclassOf: 2.5.6.0 # rdnAttId: cn rdnAttId: 2.5.4.3 # mayContain: apple-dns-domain mayContain: 1.3.6.1.4.1.63.1000.1.1.1.18.1 # mayContain: apple-dns-nameserver mayContain: 1.3.6.1.4.1.63.1000.1.1.1.18.2 possSuperiors: organizationalUnit possSuperiors: container # Class: apple-neighborhood dn: cn=apple-neighborhood,cn=Schema,cn=Configuration,dc=X changetype: ntdsschemaadd objectClass: classSchema governsID: 1.3.6.1.4.1.63.1000.1.1.2.20 ldapDisplayName: apple-neighborhood objectClassCategory: 1 # subclassOf: top subclassOf: 2.5.6.0 # rdnAttId: cn rdnAttId: 2.5.4.3 # mayContain: apple-category mayContain: 1.3.6.1.4.1.63.1000.1.1.1.10.4 # mayContain: apple-computeralias mayContain: 1.3.6.1.4.1.63.1000.1.1.1.20.3 # mayContain: apple-keyword mayContain: 1.3.6.1.4.1.63.1000.1.1.1.1.19 # mayContain: apple-neighborhoodalias mayContain: 1.3.6.1.4.1.63.1000.1.1.1.20.2 # mayContain: apple-nodepathxml mayContain: 1.3.6.1.4.1.63.1000.1.1.1.20.1 # mayContain: apple-xmlplist mayContain: 1.3.6.1.4.1.63.1000.1.1.1.17.1 # mayContain: ttl mayContain: 1.3.6.1.4.1.250.1.60 possSuperiors: 2.5.6.5 possSuperiors: container # Class: apple-serverassistant-config dn: cn=apple-serverassistant-config,cn=Schema,cn=Configuration,dc=X changetype: ntdsschemaadd objectClass: classSchema governsID: 1.3.6.1.4.1.63.1000.1.1.2.17 ldapDisplayName: apple-serverassistant-config objectClassCategory: 1 # subclassOf: top subclassOf: 2.5.6.0 # rdnAttId: cn rdnAttId: 2.5.4.3 # mayContain: apple-xmlplist mayContain: 1.3.6.1.4.1.63.1000.1.1.1.17.1 possSuperiors: organizationalUnit possSuperiors: container # Class: apple-service dn: cn=apple-service,cn=Schema,cn=Configuration,dc=X changetype: ntdsschemaadd objectClass: classSchema governsID: 1.3.6.1.4.1.63.1000.1.1.2.19 ldapDisplayName: apple-service objectClassCategory: 1 # subclassOf: top subclassOf: 2.5.6.0 # rdnAttId: cn rdnAttId: 2.5.4.3 # mustContain: apple-service-type mustContain: 1.3.6.1.4.1.63.1000.1.1.1.19.1 # mayContain: apple-dnsname mayContain: 1.3.6.1.4.1.63.1000.1.1.1.19.4 # mayContain: apple-keyword mayContain: 1.3.6.1.4.1.63.1000.1.1.1.1.19 # mayContain: apple-service-location mayContain: 1.3.6.1.4.1.63.1000.1.1.1.19.5 # mayContain: apple-service-port mayContain: 1.3.6.1.4.1.63.1000.1.1.1.19.3 # mayContain: apple-service-url mayContain: 1.3.6.1.4.1.63.1000.1.1.1.19.2 # mayContain: ipHostNumber mayContain: 1.3.6.1.1.1.1.19 possSuperiors: organizationalUnit possSuperiors: container # Class: apple-user dn: cn=apple-user,cn=Schema,cn=Configuration,dc=X changetype: ntdsschemaadd objectClass: classSchema governsID: 1.3.6.1.4.1.63.1000.1.1.2.1 ldapDisplayName: apple-user adminDescription: apple user account objectClassCategory: 3 # subclassOf: top subclassOf: 2.5.6.0 # rdnAttId: cn rdnAttId: 2.5.4.3 # mayContain: apple-imhandle mayContain: 1.3.6.1.4.1.63.1000.1.1.1.1.21 # mayContain: apple-keyword mayContain: 1.3.6.1.4.1.63.1000.1.1.1.1.19 # mayContain: apple-mcxflags mayContain: 1.3.6.1.4.1.63.1000.1.1.1.1.10 # mayContain: apple-mcxsettings mayContain: 1.3.6.1.4.1.63.1000.1.1.1.1.16 # mayContain: apple-user-authenticationhint mayContain: 1.3.6.1.4.1.63.1000.1.1.1.1.15 # mayContain: apple-user-class mayContain: 1.3.6.1.4.1.63.1000.1.1.1.1.7 # mayContain: apple-user-homequota mayContain: 1.3.6.1.4.1.63.1000.1.1.1.1.8 # mayContain: apple-user-homesoftquota mayContain: 1.3.6.1.4.1.63.1000.1.1.1.1.17 # mayContain: apple-user-homeurl mayContain: 1.3.6.1.4.1.63.1000.1.1.1.1.6 # mayContain: apple-user-mailattribute mayContain: 1.3.6.1.4.1.63.1000.1.1.1.1.9 # mayContain: apple-user-picture mayContain: 1.3.6.1.4.1.63.1000.1.1.1.1.12 # mayContain: apple-user-printattribute mayContain: 1.3.6.1.4.1.63.1000.1.1.1.1.13 # mayContain: apple-webloguri mayContain: 1.3.6.1.4.1.63.1000.1.1.1.1.22 # Class: mount dn: cn=apple-mount,cn=Schema,cn=Configuration,dc=X changetype: ntdsschemaadd objectClass: classSchema governsID: 1.3.6.1.4.1.63.1000.1.1.2.8 ldapDisplayName: mount objectClassCategory: 1 # subclassOf: top subclassOf: 2.5.6.0 # rdnAttId: cn rdnAttId: 2.5.4.3 # mayContain: mountDirectory mayContain: 1.3.6.1.4.1.63.1000.1.1.1.8.1 # mayContain: mountDumpFrequency mayContain: 1.3.6.1.4.1.63.1000.1.1.1.8.4 # mayContain: mountOption mayContain: 1.3.6.1.4.1.63.1000.1.1.1.8.3 # mayContain: mountPassNo mayContain: 1.3.6.1.4.1.63.1000.1.1.1.8.5 # mayContain: mountType mayContain: 1.3.6.1.4.1.63.1000.1.1.1.8.2 possSuperiors: 2.5.6.5 possSuperiors: container dn: changetype: modify add: schemaUpdateNow schemaUpdateNow: 1 - # ================================================================== # Updating present elements # ================================================================== # Add the new class to the user object dn: CN=User,CN=Schema,CN=Configuration,DC=X changetype: modify add: auxiliaryClass auxiliaryClass: apple-user - # Add the new class to the computer object dn: CN=Computer,CN=Schema,CN=Configuration,DC=X changetype: modify add: auxiliaryClass auxiliaryClass: apple-computer - # Add the new class to the group object dn: CN=Group,CN=Schema,CN=Configuration,DC=X changetype: modify add: auxiliaryClass auxiliaryClass: apple-group - # Add the new class to the configuration object dn: CN=Configuration,CN=Schema,CN=Configuration,DC=X changetype: modify add: auxiliaryClass auxiliaryClass: apple-configuration -

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• WMI Remote Process Starting

  - by Goober

  Scenario I've written a WMI Wrapper that seems to be quite sufficient, however whenever I run the code to start a remote process on a server, I see the process name appear in the task manager but the process itself does not start like it should (as in, I don't see the command line log window of the process that prints out what it's doing etc.) The process I am trying to start is just a C# application executable that I have written. Below is my WMI Wrapper Code and the code I am using to start running the process. Question Is the process actually running? - Even if it is only displaying the process name in the task manager and not actually launching the application to the users window? Code To Start The Process IPHostEntry hostEntry = Dns.GetHostEntry("InsertServerName"); WMIWrapper wrapper = new WMIWrapper("Insert User Name", "Insert Password", hostEntry.HostName); List<Process> processes = wrapper.GetProcesses(); foreach (Process process in processes) { if (process.Caption.Equals("MyAppName.exe")) { Console.WriteLine(process.Caption); Console.WriteLine(process.CommandLine); int processId; wrapper.StartProcess("E:\\MyData\\Data\\MyAppName.exe", out processId); Console.WriteLine(processId.ToString()); } } Console.ReadLine(); WMI Wrapper Code using System; using System.Collections.Generic; using System.Management; using System.Runtime.InteropServices; using Common.WMI.Objects; using System.Net; namespace Common.WMIWrapper { public class WMIWrapper : IDisposable { #region Constructor /// <summary> /// Creates a new instance of the wrapper /// </summary> /// <param jobName="username"></param> /// <param jobName="password"></param> /// <param jobName="server"></param> public WMIWrapper(string server) { Initialise(server); } /// <summary> /// Creates a new instance of the wrapper /// </summary> /// <param jobName="username"></param> /// <param jobName="password"></param> /// <param jobName="server"></param> public WMIWrapper(string username, string password, string server) { Initialise(username, password, server); } #endregion #region Destructor /// <summary> /// Clean up unmanaged references /// </summary> ~WMIWrapper() { Dispose(false); } #endregion #region Initialise /// <summary> /// Initialise the WMI Connection (local machine) /// </summary> /// <param name="server"></param> private void Initialise(string server) { m_server = server; // set connection options m_connectOptions = new ConnectionOptions(); IPHostEntry host = Dns.GetHostEntry(Environment.MachineName); } /// <summary> /// Initialise the WMI connection /// </summary> /// <param jobName="username">Username to connect to server with</param> /// <param jobName="password">Password to connect to server with</param> /// <param jobName="server">Server to connect to</param> private void Initialise(string username, string password, string server) { m_server = server; // set connection options m_connectOptions = new ConnectionOptions(); IPHostEntry host = Dns.GetHostEntry(Environment.MachineName); if (host.HostName.Equals(server, StringComparison.OrdinalIgnoreCase)) return; m_connectOptions.Username = username; m_connectOptions.Password = password; m_connectOptions.Impersonation = ImpersonationLevel.Impersonate; m_connectOptions.EnablePrivileges = true; } #endregion /// <summary> /// Return a list of available wmi namespaces /// </summary> /// <returns></returns> public List<String> GetWMINamespaces() { ManagementScope wmiScope = new ManagementScope(String.Format("\\\\{0}\\root", this.Server), this.ConnectionOptions); List<String> wmiNamespaceList = new List<String>(); ManagementClass wmiNamespaces = new ManagementClass(wmiScope, new ManagementPath("__namespace"), null); ; foreach (ManagementObject ns in wmiNamespaces.GetInstances()) wmiNamespaceList.Add(ns["Name"].ToString()); return wmiNamespaceList; } /// <summary> /// Return a list of available classes in a namespace /// </summary> /// <param jobName="wmiNameSpace">Namespace to get wmi classes for</param> /// <returns>List of classes in the requested namespace</returns> public List<String> GetWMIClassList(string wmiNameSpace) { ManagementScope wmiScope = new ManagementScope(String.Format("\\\\{0}\\root\\{1}", this.Server, wmiNameSpace), this.ConnectionOptions); List<String> wmiClasses = new List<String>(); ManagementObjectSearcher wmiSearcher = new ManagementObjectSearcher(wmiScope, new WqlObjectQuery("SELECT * FROM meta_Class"), null); foreach (ManagementClass wmiClass in wmiSearcher.Get()) wmiClasses.Add(wmiClass["__CLASS"].ToString()); return wmiClasses; } /// <summary> /// Get a list of wmi properties for the specified class /// </summary> /// <param jobName="wmiNameSpace">WMI Namespace</param> /// <param jobName="wmiClass">WMI Class</param> /// <returns>List of properties for the class</returns> public List<String> GetWMIClassPropertyList(string wmiNameSpace, string wmiClass) { List<String> wmiClassProperties = new List<string>(); ManagementClass managementClass = GetWMIClass(wmiNameSpace, wmiClass); foreach (PropertyData property in managementClass.Properties) wmiClassProperties.Add(property.Name); return wmiClassProperties; } /// <summary> /// Returns a list of methods for the class /// </summary> /// <param jobName="wmiNameSpace"></param> /// <param jobName="wmiClass"></param> /// <returns></returns> public List<String> GetWMIClassMethodList(string wmiNameSpace, string wmiClass) { List<String> wmiClassMethods = new List<string>(); ManagementClass managementClass = GetWMIClass(wmiNameSpace, wmiClass); foreach (MethodData method in managementClass.Methods) wmiClassMethods.Add(method.Name); return wmiClassMethods; } /// <summary> /// Retrieve the specified management class /// </summary> /// <param jobName="wmiNameSpace">Namespace of the class</param> /// <param jobName="wmiClass">Type of the class</param> /// <returns></returns> public ManagementClass GetWMIClass(string wmiNameSpace, string wmiClass) { ManagementScope wmiScope = new ManagementScope(String.Format("\\\\{0}\\root\\{1}", this.Server, wmiNameSpace), this.ConnectionOptions); ManagementClass managementClass = null; ManagementObjectSearcher wmiSearcher = new ManagementObjectSearcher(wmiScope, new WqlObjectQuery(String.Format("SELECT * FROM meta_Class WHERE __CLASS = '{0}'", wmiClass)), null); foreach (ManagementClass wmiObject in wmiSearcher.Get()) managementClass = wmiObject; return managementClass; } /// <summary> /// Get an instance of the specficied class /// </summary> /// <param jobName="wmiNameSpace">Namespace of the classes</param> /// <param jobName="wmiClass">Type of the classes</param> /// <returns>Array of management classes</returns> public ManagementObject[] GetWMIClassObjects(string wmiNameSpace, string wmiClass) { ManagementScope wmiScope = new ManagementScope(String.Format("\\\\{0}\\root\\{1}", this.Server, wmiNameSpace), this.ConnectionOptions); List<ManagementObject> wmiClasses = new List<ManagementObject>(); ManagementObjectSearcher wmiSearcher = new ManagementObjectSearcher(wmiScope, new WqlObjectQuery(String.Format("SELECT * FROM {0}", wmiClass)), null); foreach (ManagementObject wmiObject in wmiSearcher.Get()) wmiClasses.Add(wmiObject); return wmiClasses.ToArray(); } /// <summary> /// Get a full list of services /// </summary> /// <returns></returns> public List<Service> GetServices() { return GetService(null); } /// <summary> /// Get a list of services /// </summary> /// <returns></returns> public List<Service> GetService(string name) { ManagementObject[] services = GetWMIClassObjects("CIMV2", "WIN32_Service"); List<Service> serviceList = new List<Service>(); for (int i = 0; i < services.Length; i++) { ManagementObject managementObject = services[i]; Service service = new Service(managementObject); service.Status = (string)managementObject["Status"]; service.Name = (string)managementObject["Name"]; service.DisplayName = (string)managementObject["DisplayName"]; service.PathName = (string)managementObject["PathName"]; service.ProcessId = (uint)managementObject["ProcessId"]; service.Started = (bool)managementObject["Started"]; service.StartMode = (string)managementObject["StartMode"]; service.ServiceType = (string)managementObject["ServiceType"]; service.InstallDate = (string)managementObject["InstallDate"]; service.Description = (string)managementObject["Description"]; service.Caption = (string)managementObject["Caption"]; if (String.IsNullOrEmpty(name) || name.Equals(service.Name, StringComparison.OrdinalIgnoreCase)) serviceList.Add(service); } return serviceList; } /// <summary> /// Get a list of processes /// </summary> /// <returns></returns> public List<Process> GetProcesses() { return GetProcess(null); } /// <summary> /// Get a list of processes /// </summary> /// <returns></returns> public List<Process> GetProcess(uint? processId) { ManagementObject[] processes = GetWMIClassObjects("CIMV2", "WIN32_Process"); List<Process> processList = new List<Process>(); for (int i = 0; i < processes.Length; i++) { ManagementObject managementObject = processes[i]; Process process = new Process(managementObject); process.Priority = (uint)managementObject["Priority"]; process.ProcessId = (uint)managementObject["ProcessId"]; process.Status = (string)managementObject["Status"]; DateTime createDate; if (ConvertFromWmiDate((string)managementObject["CreationDate"], out createDate)) process.CreationDate = createDate.ToString("dd-MMM-yyyy HH:mm:ss"); process.Caption = (string)managementObject["Caption"]; process.CommandLine = (string)managementObject["CommandLine"]; process.Description = (string)managementObject["Description"]; process.ExecutablePath = (string)managementObject["ExecutablePath"]; process.ExecutionState = (string)managementObject["ExecutionState"]; process.MaximumWorkingSetSize = (UInt32?)managementObject ["MaximumWorkingSetSize"]; process.MinimumWorkingSetSize = (UInt32?)managementObject["MinimumWorkingSetSize"]; process.KernelModeTime = (UInt64)managementObject["KernelModeTime"]; process.ThreadCount = (UInt32)managementObject["ThreadCount"]; process.UserModeTime = (UInt64)managementObject["UserModeTime"]; process.VirtualSize = (UInt64)managementObject["VirtualSize"]; process.WorkingSetSize = (UInt64)managementObject["WorkingSetSize"]; if (processId == null || process.ProcessId == processId.Value) processList.Add(process); } return processList; } /// <summary> /// Start the specified process /// </summary> /// <param jobName="commandLine"></param> /// <returns></returns> public bool StartProcess(string command, out int processId) { processId = int.MaxValue; ManagementClass processClass = GetWMIClass("CIMV2", "WIN32_Process"); object[] objectsIn = new object[4]; objectsIn[0] = command; processClass.InvokeMethod("Create", objectsIn); if (objectsIn[3] == null) return false; processId = int.Parse(objectsIn[3].ToString()); return true; } /// <summary> /// Schedule a process on the remote machine /// </summary> /// <param name="command"></param> /// <param name="scheduleTime"></param> /// <param name="jobName"></param> /// <returns></returns> public bool ScheduleProcess(string command, DateTime scheduleTime, out string jobName) { jobName = String.Empty; ManagementClass scheduleClass = GetWMIClass("CIMV2", "Win32_ScheduledJob"); object[] objectsIn = new object[7]; objectsIn[0] = command; objectsIn[1] = String.Format("********{0:00}{1:00}{2:00}.000000+060", scheduleTime.Hour, scheduleTime.Minute, scheduleTime.Second); objectsIn[5] = true; scheduleClass.InvokeMethod("Create", objectsIn); if (objectsIn[6] == null) return false; UInt32 scheduleid = (uint)objectsIn[6]; jobName = scheduleid.ToString(); return true; } /// <summary> /// Returns the current time on the remote server /// </summary> /// <returns></returns> public DateTime Now() { ManagementScope wmiScope = new ManagementScope(String.Format("\\\\{0}\\root\\{1}", this.Server, "CIMV2"), this.ConnectionOptions); ManagementClass managementClass = null; ManagementObjectSearcher wmiSearcher = new ManagementObjectSearcher(wmiScope, new WqlObjectQuery(String.Format("SELECT * FROM Win32_LocalTime")), null); DateTime localTime = DateTime.MinValue; foreach (ManagementObject time in wmiSearcher.Get()) { UInt32 day = (UInt32)time["Day"]; UInt32 month = (UInt32)time["Month"]; UInt32 year = (UInt32)time["Year"]; UInt32 hour = (UInt32)time["Hour"]; UInt32 minute = (UInt32)time["Minute"]; UInt32 second = (UInt32)time["Second"]; localTime = new DateTime((int)year, (int)month, (int)day, (int)hour, (int)minute, (int)second); }; return localTime; } /// <summary> /// Converts a wmi date into a proper date /// </summary> /// <param jobName="wmiDate">Wmi formatted date</param> /// <returns>Date time object</returns> private static bool ConvertFromWmiDate(string wmiDate, out DateTime properDate) { properDate = DateTime.MinValue; string properDateString; // check if string is populated if (String.IsNullOrEmpty(wmiDate)) return false; wmiDate = wmiDate.Trim().ToLower().Replace("*", "0"); string[] months = new string[] { "Jan", "Feb", "Mar", "Apr", "May", "Jun", "Jul", "Aug", "Sep", "Oct", "Nov", "Dec" }; try { properDateString = String.Format("{0}-{1}-{2} {3}:{4}:{5}.{6}", wmiDate.Substring(6, 2), months[int.Parse(wmiDate.Substring(4, 2)) - 1], wmiDate.Substring(0, 4), wmiDate.Substring(8, 2), wmiDate.Substring(10, 2), wmiDate.Substring(12, 2), wmiDate.Substring(15, 6)); } catch (InvalidCastException) { return false; } catch (ArgumentOutOfRangeException) { return false; } // try and parse the new date if (!DateTime.TryParse(properDateString, out properDate)) return false; // true if conversion successful return true; } private bool m_disposed; #region IDisposable Members /// <summary> /// Managed dispose /// </summary> public void Dispose() { Dispose(true); GC.SuppressFinalize(this); } /// <summary> /// Dispose of managed and unmanaged objects /// </summary> /// <param jobName="disposing"></param> public void Dispose(bool disposing) { if (disposing) { m_connectOptions = null; } } #endregion #region Properties private ConnectionOptions m_connectOptions; /// <summary> /// Gets or sets the management scope /// </summary> private ConnectionOptions ConnectionOptions { get { return m_connectOptions; } set { m_connectOptions = value; } } private String m_server; /// <summary> /// Gets or sets the server to connect to /// </summary> public String Server { get { return m_server; } set { m_server = value; } } #endregion } }

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• Why is Java EE 6 better than Spring ?

  - by arungupta

  Java EE 6 was released over 2 years ago and now there are 14 compliant application servers. In all my talks around the world, a question that is frequently asked is Why should I use Java EE 6 instead of Spring ? There are already several blogs covering that topic: Java EE wins over Spring by Bill Burke Why will I use Java EE instead of Spring in new Enterprise Java projects in 2012 ? by Kai Waehner (more discussion on TSS) Spring to Java EE migration (Part 1 and 2, 3 and 4 coming as well) by David Heffelfinger Spring to Java EE - A Migration Experience by Lincoln Baxter Migrating Spring to Java EE 6 by Bert Ertman and Paul Bakker at NLJUG Moving from Spring to Java EE 6 - The Age of Frameworks is Over at TSS Java EE vs Spring Shootout by Rohit Kelapure and Reza Rehman at JavaOne 2011 Java EE 6 and the Ewoks by Murat Yener Definite excuse to avoid Spring forever - Bert Ertman and Arun Gupta I will try to share my perspective in this blog. First of all, I'd like to start with a note: Thank you Spring framework for filling the interim gap and providing functionality that is now included in the mainstream Java EE 6 application servers. The Java EE platform has evolved over the years learning from frameworks like Spring and provides all the functionality to build an enterprise application. Thank you very much Spring framework! While Spring was revolutionary in its time and is still very popular and quite main stream in the same way Struts was circa 2003, it really is last generation's framework - some people are even calling it legacy. However my theory is "code is king". So my approach is to build/take a simple Hello World CRUD application in Java EE 6 and Spring and compare the deployable artifacts. I started looking at the official tutorial Developing a Spring Framework MVC Application Step-by-Step but it is using the older version 2.5. I wasn't able to find any updated version in the current 3.1 release. Next, I downloaded Spring Tool Suite and thought that would provide some template samples to get started. A least a quick search did not show any handy tutorials - either video or text-based. So I searched and found a link to their SVN repository at src.springframework.org/svn/spring-samples/. I tried the "mvc-basic" sample and the generated WAR file was 4.43 MB. While it was named a "basic" sample it seemed to come with 19 different libraries bundled but it was what I could find: ./WEB-INF/lib/aopalliance-1.0.jar./WEB-INF/lib/hibernate-validator-4.1.0.Final.jar./WEB-INF/lib/jcl-over-slf4j-1.6.1.jar./WEB-INF/lib/joda-time-1.6.2.jar./WEB-INF/lib/joda-time-jsptags-1.0.2.jar./WEB-INF/lib/jstl-1.2.jar./WEB-INF/lib/log4j-1.2.16.jar./WEB-INF/lib/slf4j-api-1.6.1.jar./WEB-INF/lib/slf4j-log4j12-1.6.1.jar./WEB-INF/lib/spring-aop-3.0.5.RELEASE.jar./WEB-INF/lib/spring-asm-3.0.5.RELEASE.jar./WEB-INF/lib/spring-beans-3.0.5.RELEASE.jar./WEB-INF/lib/spring-context-3.0.5.RELEASE.jar./WEB-INF/lib/spring-context-support-3.0.5.RELEASE.jar./WEB-INF/lib/spring-core-3.0.5.RELEASE.jar./WEB-INF/lib/spring-expression-3.0.5.RELEASE.jar./WEB-INF/lib/spring-web-3.0.5.RELEASE.jar./WEB-INF/lib/spring-webmvc-3.0.5.RELEASE.jar./WEB-INF/lib/validation-api-1.0.0.GA.jar And it is not even using any database! The app deployed fine on GlassFish 3.1.2 but the "@Controller Example" link did not work as it was missing the context root. With a bit of tweaking I could deploy the application and assume that the account got created because no error was displayed in the browser or server log. Next I generated the WAR for "mvc-ajax" and the 5.1 MB WAR had 20 JARs (1 removed, 2 added): ./WEB-INF/lib/aopalliance-1.0.jar./WEB-INF/lib/hibernate-validator-4.1.0.Final.jar./WEB-INF/lib/jackson-core-asl-1.6.4.jar./WEB-INF/lib/jackson-mapper-asl-1.6.4.jar./WEB-INF/lib/jcl-over-slf4j-1.6.1.jar./WEB-INF/lib/joda-time-1.6.2.jar./WEB-INF/lib/jstl-1.2.jar./WEB-INF/lib/log4j-1.2.16.jar./WEB-INF/lib/slf4j-api-1.6.1.jar./WEB-INF/lib/slf4j-log4j12-1.6.1.jar./WEB-INF/lib/spring-aop-3.0.5.RELEASE.jar./WEB-INF/lib/spring-asm-3.0.5.RELEASE.jar./WEB-INF/lib/spring-beans-3.0.5.RELEASE.jar./WEB-INF/lib/spring-context-3.0.5.RELEASE.jar./WEB-INF/lib/spring-context-support-3.0.5.RELEASE.jar./WEB-INF/lib/spring-core-3.0.5.RELEASE.jar./WEB-INF/lib/spring-expression-3.0.5.RELEASE.jar./WEB-INF/lib/spring-web-3.0.5.RELEASE.jar./WEB-INF/lib/spring-webmvc-3.0.5.RELEASE.jar./WEB-INF/lib/validation-api-1.0.0.GA.jar 2 more JARs for just doing Ajax. Anyway, deploying this application gave the following error: Caused by: java.lang.NoSuchMethodError: org.codehaus.jackson.map.SerializationConfig.<init>(Lorg/codehaus/jackson/map/ClassIntrospector;Lorg/codehaus/jackson/map/AnnotationIntrospector;Lorg/codehaus/jackson/map/introspect/VisibilityChecker;Lorg/codehaus/jackson/map/jsontype/SubtypeResolver;)V    at org.springframework.samples.mvc.ajax.json.ConversionServiceAwareObjectMapper.<init>(ConversionServiceAwareObjectMapper.java:20)    at org.springframework.samples.mvc.ajax.json.JacksonConversionServiceConfigurer.postProcessAfterInitialization(JacksonConversionServiceConfigurer.java:40)    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.applyBeanPostProcessorsAfterInitialization(AbstractAutowireCapableBeanFactory.java:407) Seems like some incorrect repos in the "pom.xml". Next one is "mvc-showcase" and the 6.49 MB WAR now has 28 JARs as shown below: ./WEB-INF/lib/aopalliance-1.0.jar./WEB-INF/lib/aspectjrt-1.6.10.jar./WEB-INF/lib/commons-fileupload-1.2.2.jar./WEB-INF/lib/commons-io-2.0.1.jar./WEB-INF/lib/el-api-2.2.jar./WEB-INF/lib/hibernate-validator-4.1.0.Final.jar./WEB-INF/lib/jackson-core-asl-1.8.1.jar./WEB-INF/lib/jackson-mapper-asl-1.8.1.jar./WEB-INF/lib/javax.inject-1.jar./WEB-INF/lib/jcl-over-slf4j-1.6.1.jar./WEB-INF/lib/jdom-1.0.jar./WEB-INF/lib/joda-time-1.6.2.jar./WEB-INF/lib/jstl-api-1.2.jar./WEB-INF/lib/jstl-impl-1.2.jar./WEB-INF/lib/log4j-1.2.16.jar./WEB-INF/lib/rome-1.0.0.jar./WEB-INF/lib/slf4j-api-1.6.1.jar./WEB-INF/lib/slf4j-log4j12-1.6.1.jar./WEB-INF/lib/spring-aop-3.1.0.RELEASE.jar./WEB-INF/lib/spring-asm-3.1.0.RELEASE.jar./WEB-INF/lib/spring-beans-3.1.0.RELEASE.jar./WEB-INF/lib/spring-context-3.1.0.RELEASE.jar./WEB-INF/lib/spring-context-support-3.1.0.RELEASE.jar./WEB-INF/lib/spring-core-3.1.0.RELEASE.jar./WEB-INF/lib/spring-expression-3.1.0.RELEASE.jar./WEB-INF/lib/spring-web-3.1.0.RELEASE.jar./WEB-INF/lib/spring-webmvc-3.1.0.RELEASE.jar./WEB-INF/lib/validation-api-1.0.0.GA.jar The app at least deployed and showed results this time. But still no database! Next I tried building "jpetstore" and got the error: [ERROR] Failed to execute goal on project org.springframework.samples.jpetstore:Could not resolve dependencies for project org.springframework.samples:org.springframework.samples.jpetstore:war:1.0.0-SNAPSHOT: Failed to collect dependencies for [commons-fileupload:commons-fileupload:jar:1.2.1 (compile), org.apache.struts:com.springsource.org.apache.struts:jar:1.2.9 (compile), javax.xml.rpc:com.springsource.javax.xml.rpc:jar:1.1.0 (compile), org.apache.commons:com.springsource.org.apache.commons.dbcp:jar:1.2.2.osgi (compile), commons-io:commons-io:jar:1.3.2 (compile), hsqldb:hsqldb:jar:1.8.0.7 (compile), org.apache.tiles:tiles-core:jar:2.2.0 (compile), org.apache.tiles:tiles-jsp:jar:2.2.0 (compile), org.tuckey:urlrewritefilter:jar:3.1.0 (compile), org.springframework:spring-webmvc:jar:3.0.0.BUILD-SNAPSHOT (compile), org.springframework:spring-orm:jar:3.0.0.BUILD-SNAPSHOT (compile), org.springframework:spring-context-support:jar:3.0.0.BUILD-SNAPSHOT (compile), org.springframework.webflow:spring-js:jar:2.0.7.RELEASE (compile), org.apache.ibatis:com.springsource.com.ibatis:jar:2.3.4.726 (runtime), com.caucho:com.springsource.com.caucho:jar:3.2.1 (compile), org.apache.axis:com.springsource.org.apache.axis:jar:1.4.0 (compile), javax.wsdl:com.springsource.javax.wsdl:jar:1.6.1 (compile), javax.servlet:jstl:jar:1.2 (runtime), org.aspectj:aspectjweaver:jar:1.6.5 (compile), javax.servlet:servlet-api:jar:2.5 (provided), javax.servlet.jsp:jsp-api:jar:2.1 (provided), junit:junit:jar:4.6 (test)]: Failed to read artifact descriptor for org.springframework:spring-webmvc:jar:3.0.0.BUILD-SNAPSHOT: Could not transfer artifact org.springframework:spring-webmvc:pom:3.0.0.BUILD-SNAPSHOT from/to JBoss repository (http://repository.jboss.com/maven2): Access denied to: http://repository.jboss.com/maven2/org/springframework/spring-webmvc/3.0.0.BUILD-SNAPSHOT/spring-webmvc-3.0.0.BUILD-SNAPSHOT.pom It appears the sample is broken - maybe I was pulling from the wrong repository - would be great if someone were to point me at a good target to use here. With a 50% hit on samples in this repository, I started searching through numerous blogs, most of which have either outdated information (using XML-heavy Spring 2.5), some piece of configuration (which is a typical "feature" of Spring) is missing, or too much complexity in the sample. I finally found this blog that worked like a charm. This blog creates a trivial Spring MVC 3 application using Hibernate and MySQL. This application performs CRUD operations on a single table in a database using typical Spring technologies.  I downloaded the sample code from the blog, deployed it on GlassFish 3.1.2 and could CRUD the "person" entity. The source code for this application can be downloaded here. More details on the application statistics below. And then I built a similar CRUD application in Java EE 6 using NetBeans wizards in a couple of minutes. The source code for the application can be downloaded here and the WAR here. The Spring Source Tool Suite may also offer similar wizard-driven capabilities but this blog focus primarily on comparing the runtimes. The lack of STS tutorials was slightly disappointing as well. NetBeans however has tons of text-based and video tutorials and tons of material even by the community. One more bit on the download size of tools bundle ... NetBeans 7.1.1 "All" is 211 MB (which includes GlassFish and Tomcat) Spring Tool Suite  2.9.0 is 347 MB (~ 65% bigger) This blog is not about the tooling comparison so back to the Java EE 6 version of the application .... In order to run the Java EE version on GlassFish, copy the MySQL Connector/J to glassfish3/glassfish/domains/domain1/lib/ext directory and create a JDBC connection pool and JDBC resource as: ./bin/asadmin create-jdbc-connection-pool --datasourceclassname \\ com.mysql.jdbc.jdbc2.optional.MysqlDataSource --restype \\ javax.sql.DataSource --property \\ portNumber=3306:user=mysql:password=mysql:databaseName=mydatabase \\ myConnectionPool ./bin/asadmin create-jdbc-resource --connectionpoolid myConnectionPool jdbc/myDataSource I generated WARs for the two projects and the table below highlights some differences between them: Java EE 6 Spring WAR File Size 0.021030 MB 10.87 MB (~516x) Number of files 20 53 (> 2.5x) Bundled libraries 0 36 Total size of libraries 0 12.1 MB XML files 3 5 LoC in XML files 50 (11 + 15 + 24) 129 (27 + 46 + 16 + 11 + 19) (~ 2.5x) Total .properties files 1 Bundle.properties 2 spring.properties, log4j.properties Cold Deploy 5,339 ms 11,724 ms Second Deploy 481 ms 6,261 ms Third Deploy 528 ms 5,484 ms Fourth Deploy 484 ms 5,576 ms Runtime memory ~73 MB ~101 MB Some points worth highlighting from the table ... 516x WAR file, 10x deployment time - With 12.1 MB of libraries (for a very basic application) bundled in your application, the WAR file size and the deployment time will naturally go higher. The WAR file for Spring-based application is 516x bigger and the deployment time is double during the first deployment and ~ 10x during subsequent deployments. The Java EE 6 application is fully portable and will run on any Java EE 6 compliant application server. 36 libraries in the WAR - There are 14 Java EE 6 compliant application servers today. Each of those servers provide all the functionality like transactions, dependency injection, security, persistence, etc typically required of an enterprise or web application. There is no need to bundle 36 libraries worth 12.1 MB for a trivial CRUD application. These 14 compliant application servers provide all the functionality baked in. Now you can also deploy these libraries in the container but then you don't get the "portability" offered by Spring in that case. Does your typical Spring deployment actually do that ? 3x LoC in XML - The number of XML files is about 1.6x and the LoC is ~ 2.5x. So much XML seems circa 2003 when the Java language had no annotations. The XML files can be further reduced, e.g. faces-config.xml can be replaced without providing i18n, but I just want to compare stock applications. Memory usage - Both the applications were deployed on default GlassFish 3.1.2 installation and any additional memory consumed as part of deployment/access was attributed to the application. This is by no means scientific but at least provides an initial ballpark. This area definitely needs more investigation. Another table that compares typical Java EE 6 compliant application servers and the custom-stack created for a Spring application ... Java EE 6 Spring Web Container ? 53 MB (tcServer 2.6.3 Developer Edition) Security ? 12 MB (Spring Security 3.1.0) Persistence ? 6.3 MB (Hibernate 4.1.0, required) Dependency Injection ? 5.3 MB (Framework) Web Services ? 796 KB (Spring WS 2.0.4) Messaging ? 3.4 MB (RabbitMQ Server 2.7.1) 936 KB (Java client 936) OSGi ? 1.3 MB (Spring OSGi 1.2.1) GlassFish and WebLogic (starting at 33 MB) 83.3 MB There are differentiating factors on both the stacks. But most of the functionality like security, persistence, and dependency injection is baked in a Java EE 6 compliant application server but needs to be individually managed and patched for a Spring application. This very quickly leads to a "stack explosion". The Java EE 6 servers are tested extensively on a variety of platforms in different combinations whereas a Spring application developer is responsible for testing with different JDKs, Operating Systems, Versions, Patches, etc. Oracle has both the leading OSS lightweight server with GlassFish and the leading enterprise Java server with WebLogic Server, both Java EE 6 and both with lightweight deployment options. The Web Container offered as part of a Java EE 6 application server not only deploys your enterprise Java applications but also provide operational management, diagnostics, and mission-critical capabilities required by your applications. The Java EE 6 platform also introduced the Web Profile which is a subset of the specifications from the entire platform. It is targeted at developers of modern web applications offering a reasonably complete stack, composed of standard APIs, and is capable out-of-the-box of addressing the needs of a large class of Web applications. As your applications grow, the stack can grow to the full Java EE 6 platform. The GlassFish Server Web Profile starting at 33MB (smaller than just the non-standard tcServer) provides most of the functionality typically required by a web application. WebLogic provides battle-tested functionality for a high throughput, low latency, and enterprise grade web application. No individual managing or patching, all tested and commercially supported for you! Note that VMWare does have a server, tcServer, but it is non-standard and not even certified to the level of the standard Web Profile most customers expect these days. Customers who choose this risk proprietary lock-in since VMWare does not seem to want to formally certify with either Java EE 6 Enterprise Platform or with Java EE 6 Web Profile but of course it would be great if they were to join the community and help their customers reduce the risk of deploying on VMWare software. Some more points to help you decide choose between Java EE 6 and Spring ... Freedom to choose container - There are 14 Java EE 6 compliant application servers today, with a variety of open source and commercial offerings. A Java EE 6 application can be deployed on any of those containers. So if you deployed your application on GlassFish today and would like to scale up with your demands then you can deploy the same application to WebLogic. And because of the portability of a Java EE 6 application, you can even take it a different vendor altogether. Spring requires a runtime which could be any of these app servers as well. But why use Spring when all the required functionality is already baked into the application server itself ? Spring also has a different definition of portability where they claim to bundle all the libraries in the WAR file and move to any application server. But we saw earlier how bloated that archive could be. The equivalent features in Spring runtime offerings (mainly tcServer) are not all open source, not as mature, and often require manual assembly.  Vendor choice - The Java EE 6 platform is created using the Java Community Process where all the big players like Oracle, IBM, RedHat, and Apache are conritbuting to make the platform successful. Each application server provides the basic Java EE 6 platform compliance and has its own competitive offerings. This allows you to choose an application server for deploying your Java EE 6 applications. If you are not happy with the support or feature of one vendor then you can move your application to a different vendor because of the portability promise offered by the platform. Spring is a set of products from a single company, one price book, one support organization, one sustaining organization, one sales organization, etc. If any of those cause a customer headache, where do you go ? Java EE, backed by multiple vendors, is a safer bet for those that are risk averse. Production support - With Spring, typically you need to get support from two vendors - VMWare and the container provider. With Java EE 6, all of this is typically provided by one vendor. For example, Oracle offers commercial support from systems, operating systems, JDK, application server, and applications on top of them. VMWare certainly offers complete production support but do you really want to put all your eggs in one basket ? Do you really use tcServer ? ;-) Maintainability - With Spring, you are likely building your own distribution with multiple JAR files, integrating, patching, versioning, etc of all those components. Spring's claim is that multiple JAR files allow you to go à la carte and pick the latest versions of different components. But who is responsible for testing whether all these versions work together ? Yep, you got it, its YOU! If something does not work, who patches and maintains the JARs ? Of course, you! Commercial support for such a configuration ? On your own! The Java EE application servers manage all of this for you and provide a well-tested and commercially supported bundle. While it is always good to realize that there is something new and improved that updates and replaces older frameworks like Spring, the good news is not only does a Java EE 6 container offer what is described here, most also will let you deploy and run your Spring applications on them while you go through an upgrade to a more modern architecture. End result, you get the best of both worlds - keeping your legacy investment but moving to a more agile, lightweight world of Java EE 6. A message to the Spring lovers ... The complexity in J2EE 1.2, 1.3, and 1.4 led to the genesis of Spring but that was in 2004. This is 2012 and the name has changed to "Java EE 6" :-) There are tons of improvements in the Java EE platform to make it easy-to-use and powerful. Some examples: Adding @Stateless on a POJO makes it an EJB EJBs can be packaged in a WAR with no special packaging or deployment descriptors "web.xml" and "faces-config.xml" are optional in most of the common cases Typesafe dependency injection is now part of the Java EE platform Add @Path on a POJO allows you to publish it as a RESTful resource EJBs can be used as backing beans for Facelets-driven JSF pages providing full MVC Java EE 6 WARs are known to be kilobytes in size and deployed in milliseconds Tons of other simplifications in the platform and application servers So if you moved away from J2EE to Spring many years ago and have not looked at Java EE 6 (which has been out since Dec 2009) then you should definitely try it out. Just be at least aware of what other alternatives are available instead of restricting yourself to one stack. Here are some workshops and screencasts worth trying: screencast #37 shows how to build an end-to-end application using NetBeans screencast #36 builds the same application using Eclipse javaee-lab-feb2012.pdf is a 3-4 hours self-paced hands-on workshop that guides you to build a comprehensive Java EE 6 application using NetBeans Each city generally has a "spring cleanup" program every year. It allows you to clean up the mess from your house. For your software projects, you don't need to wait for an annual event, just get started and reduce the technical debt now! Move away from your legacy Spring-based applications to a lighter and more modern approach of building enterprise Java applications using Java EE 6. Watch this beautiful presentation that explains how to migrate from Spring -> Java EE 6: List of files in the Java EE 6 project: ./index.xhtml./META-INF./person./person/Create.xhtml./person/Edit.xhtml./person/List.xhtml./person/View.xhtml./resources./resources/css./resources/css/jsfcrud.css./template.xhtml./WEB-INF./WEB-INF/classes./WEB-INF/classes/Bundle.properties./WEB-INF/classes/META-INF./WEB-INF/classes/META-INF/persistence.xml./WEB-INF/classes/org./WEB-INF/classes/org/javaee./WEB-INF/classes/org/javaee/javaeemysql./WEB-INF/classes/org/javaee/javaeemysql/AbstractFacade.class./WEB-INF/classes/org/javaee/javaeemysql/Person.class./WEB-INF/classes/org/javaee/javaeemysql/Person_.class./WEB-INF/classes/org/javaee/javaeemysql/PersonController$1.class./WEB-INF/classes/org/javaee/javaeemysql/PersonController$PersonControllerConverter.class./WEB-INF/classes/org/javaee/javaeemysql/PersonController.class./WEB-INF/classes/org/javaee/javaeemysql/PersonFacade.class./WEB-INF/classes/org/javaee/javaeemysql/util./WEB-INF/classes/org/javaee/javaeemysql/util/JsfUtil.class./WEB-INF/classes/org/javaee/javaeemysql/util/PaginationHelper.class./WEB-INF/faces-config.xml./WEB-INF/web.xml List of files in the Spring 3.x project: ./META-INF ./META-INF/MANIFEST.MF./WEB-INF./WEB-INF/applicationContext.xml./WEB-INF/classes./WEB-INF/classes/log4j.properties./WEB-INF/classes/org./WEB-INF/classes/org/krams ./WEB-INF/classes/org/krams/tutorial ./WEB-INF/classes/org/krams/tutorial/controller ./WEB-INF/classes/org/krams/tutorial/controller/MainController.class ./WEB-INF/classes/org/krams/tutorial/domain ./WEB-INF/classes/org/krams/tutorial/domain/Person.class ./WEB-INF/classes/org/krams/tutorial/service ./WEB-INF/classes/org/krams/tutorial/service/PersonService.class ./WEB-INF/hibernate-context.xml ./WEB-INF/hibernate.cfg.xml ./WEB-INF/jsp ./WEB-INF/jsp/addedpage.jsp ./WEB-INF/jsp/addpage.jsp ./WEB-INF/jsp/deletedpage.jsp ./WEB-INF/jsp/editedpage.jsp ./WEB-INF/jsp/editpage.jsp ./WEB-INF/jsp/personspage.jsp ./WEB-INF/lib ./WEB-INF/lib/antlr-2.7.6.jar ./WEB-INF/lib/aopalliance-1.0.jar ./WEB-INF/lib/c3p0-0.9.1.2.jar ./WEB-INF/lib/cglib-nodep-2.2.jar ./WEB-INF/lib/commons-beanutils-1.8.3.jar ./WEB-INF/lib/commons-collections-3.2.1.jar ./WEB-INF/lib/commons-digester-2.1.jar ./WEB-INF/lib/commons-logging-1.1.1.jar ./WEB-INF/lib/dom4j-1.6.1.jar ./WEB-INF/lib/ejb3-persistence-1.0.2.GA.jar ./WEB-INF/lib/hibernate-annotations-3.4.0.GA.jar ./WEB-INF/lib/hibernate-commons-annotations-3.1.0.GA.jar ./WEB-INF/lib/hibernate-core-3.3.2.GA.jar ./WEB-INF/lib/javassist-3.7.ga.jar ./WEB-INF/lib/jstl-1.1.2.jar ./WEB-INF/lib/jta-1.1.jar ./WEB-INF/lib/junit-4.8.1.jar ./WEB-INF/lib/log4j-1.2.14.jar ./WEB-INF/lib/mysql-connector-java-5.1.14.jar ./WEB-INF/lib/persistence-api-1.0.jar ./WEB-INF/lib/slf4j-api-1.6.1.jar ./WEB-INF/lib/slf4j-log4j12-1.6.1.jar ./WEB-INF/lib/spring-aop-3.0.5.RELEASE.jar ./WEB-INF/lib/spring-asm-3.0.5.RELEASE.jar ./WEB-INF/lib/spring-beans-3.0.5.RELEASE.jar ./WEB-INF/lib/spring-context-3.0.5.RELEASE.jar ./WEB-INF/lib/spring-context-support-3.0.5.RELEASE.jar ./WEB-INF/lib/spring-core-3.0.5.RELEASE.jar ./WEB-INF/lib/spring-expression-3.0.5.RELEASE.jar ./WEB-INF/lib/spring-jdbc-3.0.5.RELEASE.jar ./WEB-INF/lib/spring-orm-3.0.5.RELEASE.jar ./WEB-INF/lib/spring-tx-3.0.5.RELEASE.jar ./WEB-INF/lib/spring-web-3.0.5.RELEASE.jar ./WEB-INF/lib/spring-webmvc-3.0.5.RELEASE.jar ./WEB-INF/lib/standard-1.1.2.jar ./WEB-INF/lib/xml-apis-1.0.b2.jar ./WEB-INF/spring-servlet.xml ./WEB-INF/spring.properties ./WEB-INF/web.xml So, are you excited about Java EE 6 ? Want to get started now ? Here are some resources: Java EE 6 SDK (including runtime, samples, tutorials etc) GlassFish Server Open Source Edition 3.1.2 (Community) Oracle GlassFish Server 3.1.2 (Commercial) Java EE 6 using WebLogic 12c and NetBeans (Video) Java EE 6 with NetBeans and GlassFish (Video) Java EE with Eclipse and GlassFish (Video)

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• Cleaner HTML Markup with ASP.NET 4 Web Forms - Client IDs (VS 2010 and .NET 4.0 Series)

  - by ScottGu

  This is the sixteenth in a series of blog posts I’m doing on the upcoming VS 2010 and .NET 4 release. Today’s post is the first of a few blog posts I’ll be doing that talk about some of the important changes we’ve made to make Web Forms in ASP.NET 4 generate clean, standards-compliant, CSS-friendly markup.  Today I’ll cover the work we are doing to provide better control over the “ID” attributes rendered by server controls to the client. [In addition to blogging, I am also now using Twitter for quick updates and to share links. Follow me at: twitter.com/scottgu] Clean, Standards-Based, CSS-Friendly Markup One of the common complaints developers have often had with ASP.NET Web Forms is that when using server controls they don’t have the ability to easily generate clean, CSS-friendly output and markup.  Some of the specific complaints with previous ASP.NET releases include: Auto-generated ID attributes within HTML make it hard to write JavaScript and style with CSS Use of tables instead of semantic markup for certain controls (in particular the asp:menu control) make styling ugly Some controls render inline style properties even if no style property on the control has been set ViewState can often be bigger than ideal ASP.NET 4 provides better support for building standards-compliant pages out of the box.  The built-in <asp:> server controls with ASP.NET 4 now generate cleaner markup and support CSS styling – and help address all of the above issues.  Markup Compatibility When Upgrading Existing ASP.NET Web Forms Applications A common question people often ask when hearing about the cleaner markup coming with ASP.NET 4 is “Great - but what about my existing applications?  Will these changes/improvements break things when I upgrade?” To help ensure that we don’t break assumptions around markup and styling with existing ASP.NET Web Forms applications, we’ve enabled a configuration flag – controlRenderingCompatbilityVersion – within web.config that let’s you decide if you want to use the new cleaner markup approach that is the default with new ASP.NET 4 applications, or for compatibility reasons render the same markup that previous versions of ASP.NET used:   When the controlRenderingCompatbilityVersion flag is set to “3.5” your application and server controls will by default render output using the same markup generation used with VS 2008 and .NET 3.5.  When the controlRenderingCompatbilityVersion flag is set to “4.0” your application and server controls will strictly adhere to the XHTML 1.1 specification, have cleaner client IDs, render with semantic correctness in mind, and have extraneous inline styles removed. This flag defaults to 4.0 for all new ASP.NET Web Forms applications built using ASP.NET 4. Any previous application that is upgraded using VS 2010 will have the controlRenderingCompatbilityVersion flag automatically set to 3.5 by the upgrade wizard to ensure backwards compatibility.  You can then optionally change it (either at the application level, or scope it within the web.config file to be on a per page or directory level) if you move your pages to use CSS and take advantage of the new markup rendering. Today’s Cleaner Markup Topic: Client IDs The ability to have clean, predictable, ID attributes on rendered HTML elements is something developers have long asked for with Web Forms (ID values like “ctl00_ContentPlaceholder1_ListView1_ctrl0_Label1” are not very popular).  Having control over the ID values rendered helps make it much easier to write client-side JavaScript against the output, makes it easier to style elements using CSS, and on large pages can help reduce the overall size of the markup generated. New ClientIDMode Property on Controls ASP.NET 4 supports a new ClientIDMode property on the Control base class.  The ClientIDMode property indicates how controls should generate client ID values when they render.  The ClientIDMode property supports four possible values: AutoID—Renders the output as in .NET 3.5 (auto-generated IDs which will still render prefixes like ctrl00 for compatibility) Predictable (Default)— Trims any “ctl00” ID string and if a list/container control concatenates child ids (example: id=”ParentControl_ChildControl”) Static—Hands over full ID naming control to the developer – whatever they set as the ID of the control is what is rendered (example: id=”JustMyId”) Inherit—Tells the control to defer to the naming behavior mode of the parent container control The ClientIDMode property can be set directly on individual controls (or within container controls – in which case the controls within them will by default inherit the setting): Or it can be specified at a page or usercontrol level (using the <%@ Page %> or <%@ Control %> directives) – in which case controls within the pages/usercontrols inherit the setting (and can optionally override it): Or it can be set within the web.config file of an application – in which case pages within the application inherit the setting (and can optionally override it): This gives you the flexibility to customize/override the naming behavior however you want. Example: Using the ClientIDMode property to control the IDs of Non-List Controls Let’s take a look at how we can use the new ClientIDMode property to control the rendering of “ID” elements within a page.  To help illustrate this we can create a simple page called “SingleControlExample.aspx” that is based on a master-page called “Site.Master”, and which has a single <asp:label> control with an ID of “Message” that is contained with an <asp:content> container control called “MainContent”: Within our code-behind we’ll then add some simple code like below to dynamically populate the Label’s Text property at runtime:   If we were running this application using ASP.NET 3.5 (or had our ASP.NET 4 application configured to run using 3.5 rendering or ClientIDMode=AutoID), then the generated markup sent down to the client would look like below: This ID is unique (which is good) – but rather ugly because of the “ct100” prefix (which is bad). Markup Rendering when using ASP.NET 4 and the ClientIDMode is set to “Predictable” With ASP.NET 4, server controls by default now render their ID’s using ClientIDMode=”Predictable”.  This helps ensure that ID values are still unique and don’t conflict on a page, but at the same time it makes the IDs less verbose and more predictable.  This means that the generated markup of our <asp:label> control above will by default now look like below with ASP.NET 4: Notice that the “ct100” prefix is gone. Because the “Message” control is embedded within a “MainContent” container control, by default it’s ID will be prefixed “MainContent_Message” to avoid potential collisions with other controls elsewhere within the page. Markup Rendering when using ASP.NET 4 and the ClientIDMode is set to “Static” Sometimes you don’t want your ID values to be nested hierarchically, though, and instead just want the ID rendered to be whatever value you set it as.  To enable this you can now use ClientIDMode=static, in which case the ID rendered will be exactly the same as what you set it on the server-side on your control.  This will cause the below markup to be rendered with ASP.NET 4: This option now gives you the ability to completely control the client ID values sent down by controls. Example: Using the ClientIDMode property to control the IDs of Data-Bound List Controls Data-bound list/grid controls have historically been the hardest to use/style when it comes to working with Web Form’s automatically generated IDs.  Let’s now take a look at a scenario where we’ll customize the ID’s rendered using a ListView control with ASP.NET 4. The code snippet below is an example of a ListView control that displays the contents of a data-bound collection — in this case, airports: We can then write code like below within our code-behind to dynamically databind a list of airports to the ListView above: At runtime this will then by default generate a <ul> list of airports like below.  Note that because the <ul> and <li> elements in the ListView’s template are not server controls, no IDs are rendered in our markup: Adding Client ID’s to Each Row Item Now, let’s say that we wanted to add client-ID’s to the output so that we can programmatically access each <li> via JavaScript.  We want these ID’s to be unique, predictable, and identifiable. A first approach would be to mark each <li> element within the template as being a server control (by giving it a runat=server attribute) and by giving each one an id of “airport”: By default ASP.NET 4 will now render clean IDs like below (no ctl001-like ids are rendered):   Using the ClientIDRowSuffix Property Our template above now generates unique ID’s for each <li> element – but if we are going to access them programmatically on the client using JavaScript we might want to instead have the ID’s contain the airport code within them to make them easier to reference.  The good news is that we can easily do this by taking advantage of the new ClientIDRowSuffix property on databound controls in ASP.NET 4 to better control the ID’s of our individual row elements. To do this, we’ll set the ClientIDRowSuffix property to “Code” on our ListView control.  This tells the ListView to use the databound “Code” property from our Airport class when generating the ID: And now instead of having row suffixes like “1”, “2”, and “3”, we’ll instead have the Airport.Code value embedded within the IDs (e.g: _CLE, _CAK, _PDX, etc): You can use this ClientIDRowSuffix approach with other databound controls like the GridView as well. It is useful anytime you want to program row elements on the client – and use clean/identified IDs to easily reference them from JavaScript code. Summary ASP.NET 4 enables you to generate much cleaner HTML markup from server controls and from within your Web Forms applications.  In today’s post I covered how you can now easily control the client ID values that are rendered by server controls.  In upcoming posts I’ll cover some of the other markup improvements that are also coming with the ASP.NET 4 release. Hope this helps, Scott

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• C#/.NET Little Wonders: The Concurrent Collections (1 of 3)

  - by James Michael Hare

  Once again we consider some of the lesser known classes and keywords of C#.  In the next few weeks, we will discuss the concurrent collections and how they have changed the face of concurrent programming. This week’s post will begin with a general introduction and discuss the ConcurrentStack<T> and ConcurrentQueue<T>.  Then in the following post we’ll discuss the ConcurrentDictionary<T> and ConcurrentBag<T>.  Finally, we shall close on the third post with a discussion of the BlockingCollection<T>. For more of the "Little Wonders" posts, see the index here. A brief history of collections In the beginning was the .NET 1.0 Framework.  And out of this framework emerged the System.Collections namespace, and it was good.  It contained all the basic things a growing programming language needs like the ArrayList and Hashtable collections.  The main problem, of course, with these original collections is that they held items of type object which means you had to be disciplined enough to use them correctly or you could end up with runtime errors if you got an object of a type you weren't expecting. Then came .NET 2.0 and generics and our world changed forever!  With generics the C# language finally got an equivalent of the very powerful C++ templates.  As such, the System.Collections.Generic was born and we got type-safe versions of all are favorite collections.  The List<T> succeeded the ArrayList and the Dictionary<TKey,TValue> succeeded the Hashtable and so on.  The new versions of the library were not only safer because they checked types at compile-time, in many cases they were more performant as well.  So much so that it's Microsoft's recommendation that the System.Collections original collections only be used for backwards compatibility. So we as developers came to know and love the generic collections and took them into our hearts and embraced them.  The problem is, thread safety in both the original collections and the generic collections can be problematic, for very different reasons. Now, if you are only doing single-threaded development you may not care – after all, no locking is required.  Even if you do have multiple threads, if a collection is “load-once, read-many” you don’t need to do anything to protect that container from multi-threaded access, as illustrated below: 1: public static class OrderTypeTranslator 2: { 3: // because this dictionary is loaded once before it is ever accessed, we don't need to synchronize 4: // multi-threaded read access 5: private static readonly Dictionary<string, char> _translator = new Dictionary<string, char> 6: { 7: {"New", 'N'}, 8: {"Update", 'U'}, 9: {"Cancel", 'X'} 10: }; 11:  12: // the only public interface into the dictionary is for reading, so inherently thread-safe 13: public static char? Translate(string orderType) 14: { 15: char charValue; 16: if (_translator.TryGetValue(orderType, out charValue)) 17: { 18: return charValue; 19: } 20:  21: return null; 22: } 23: } Unfortunately, most of our computer science problems cannot get by with just single-threaded applications or with multi-threading in a load-once manner.  Looking at  today's trends, it's clear to see that computers are not so much getting faster because of faster processor speeds -- we've nearly reached the limits we can push through with today's technologies -- but more because we're adding more cores to the boxes.  With this new hardware paradigm, it is even more important to use multi-threaded applications to take full advantage of parallel processing to achieve higher application speeds. So let's look at how to use collections in a thread-safe manner. Using historical collections in a concurrent fashion The early .NET collections (System.Collections) had a Synchronized() static method that could be used to wrap the early collections to make them completely thread-safe.  This paradigm was dropped in the generic collections (System.Collections.Generic) because having a synchronized wrapper resulted in atomic locks for all operations, which could prove overkill in many multithreading situations.  Thus the paradigm shifted to having the user of the collection specify their own locking, usually with an external object: 1: public class OrderAggregator 2: { 3: private static readonly Dictionary<string, List<Order>> _orders = new Dictionary<string, List<Order>>(); 4: private static readonly _orderLock = new object(); 5:  6: public void Add(string accountNumber, Order newOrder) 7: { 8: List<Order> ordersForAccount; 9:  10: // a complex operation like this should all be protected 11: lock (_orderLock) 12: { 13: if (!_orders.TryGetValue(accountNumber, out ordersForAccount)) 14: { 15: _orders.Add(accountNumber, ordersForAccount = new List<Order>()); 16: } 17:  18: ordersForAccount.Add(newOrder); 19: } 20: } 21: } Notice how we’re performing several operations on the dictionary under one lock.  With the Synchronized() static methods of the early collections, you wouldn’t be able to specify this level of locking (a more macro-level).  So in the generic collections, it was decided that if a user needed synchronization, they could implement their own locking scheme instead so that they could provide synchronization as needed. The need for better concurrent access to collections Here’s the problem: it’s relatively easy to write a collection that locks itself down completely for access, but anything more complex than that can be difficult and error-prone to write, and much less to make it perform efficiently!  For example, what if you have a Dictionary that has frequent reads but in-frequent updates?  Do you want to lock down the entire Dictionary for every access?  This would be overkill and would prevent concurrent reads.  In such cases you could use something like a ReaderWriterLockSlim which allows for multiple readers in a lock, and then once a writer grabs the lock it blocks all further readers until the writer is done (in a nutshell).  This is all very complex stuff to consider. Fortunately, this is where the Concurrent Collections come in.  The Parallel Computing Platform team at Microsoft went through great pains to determine how to make a set of concurrent collections that would have the best performance characteristics for general case multi-threaded use. Now, as in all things involving threading, you should always make sure you evaluate all your container options based on the particular usage scenario and the degree of parallelism you wish to acheive. This article should not be taken to understand that these collections are always supperior to the generic collections. Each fills a particular need for a particular situation. Understanding what each container is optimized for is key to the success of your application whether it be single-threaded or multi-threaded. General points to consider with the concurrent collections The MSDN points out that the concurrent collections all support the ICollection interface. However, since the collections are already synchronized, the IsSynchronized property always returns false, and SyncRoot always returns null.  Thus you should not attempt to use these properties for synchronization purposes. Note that since the concurrent collections also may have different operations than the traditional data structures you may be used to.  Now you may ask why they did this, but it was done out of necessity to keep operations safe and atomic.  For example, in order to do a Pop() on a stack you have to know the stack is non-empty, but between the time you check the stack’s IsEmpty property and then do the Pop() another thread may have come in and made the stack empty!  This is why some of the traditional operations have been changed to make them safe for concurrent use. In addition, some properties and methods in the concurrent collections achieve concurrency by creating a snapshot of the collection, which means that some operations that were traditionally O(1) may now be O(n) in the concurrent models.  I’ll try to point these out as we talk about each collection so you can be aware of any potential performance impacts.  Finally, all the concurrent containers are safe for enumeration even while being modified, but some of the containers support this in different ways (snapshot vs. dirty iteration).  Once again I’ll highlight how thread-safe enumeration works for each collection. ConcurrentStack<T>: The thread-safe LIFO container The ConcurrentStack<T> is the thread-safe counterpart to the System.Collections.Generic.Stack<T>, which as you may remember is your standard last-in-first-out container.  If you think of algorithms that favor stack usage (for example, depth-first searches of graphs and trees) then you can see how using a thread-safe stack would be of benefit. The ConcurrentStack<T> achieves thread-safe access by using System.Threading.Interlocked operations.  This means that the multi-threaded access to the stack requires no traditional locking and is very, very fast! For the most part, the ConcurrentStack<T> behaves like it’s Stack<T> counterpart with a few differences: Pop() was removed in favor of TryPop() Returns true if an item existed and was popped and false if empty. PushRange() and TryPopRange() were added Allows you to push multiple items and pop multiple items atomically. Count takes a snapshot of the stack and then counts the items. This means it is a O(n) operation, if you just want to check for an empty stack, call IsEmpty instead which is O(1). ToArray() and GetEnumerator() both also take snapshots. This means that iteration over a stack will give you a static view at the time of the call and will not reflect updates. Pushing on a ConcurrentStack<T> works just like you’d expect except for the aforementioned PushRange() method that was added to allow you to push a range of items concurrently. 1: var stack = new ConcurrentStack<string>(); 2:  3: // adding to stack is much the same as before 4: stack.Push("First"); 5:  6: // but you can also push multiple items in one atomic operation (no interleaves) 7: stack.PushRange(new [] { "Second", "Third", "Fourth" }); For looking at the top item of the stack (without removing it) the Peek() method has been removed in favor of a TryPeek().  This is because in order to do a peek the stack must be non-empty, but between the time you check for empty and the time you execute the peek the stack contents may have changed.  Thus the TryPeek() was created to be an atomic check for empty, and then peek if not empty: 1: // to look at top item of stack without removing it, can use TryPeek. 2: // Note that there is no Peek(), this is because you need to check for empty first. TryPeek does. 3: string item; 4: if (stack.TryPeek(out item)) 5: { 6: Console.WriteLine("Top item was " + item); 7: } 8: else 9: { 10: Console.WriteLine("Stack was empty."); 11: } Finally, to remove items from the stack, we have the TryPop() for single, and TryPopRange() for multiple items.  Just like the TryPeek(), these operations replace Pop() since we need to ensure atomically that the stack is non-empty before we pop from it: 1: // to remove items, use TryPop or TryPopRange to get multiple items atomically (no interleaves) 2: if (stack.TryPop(out item)) 3: { 4: Console.WriteLine("Popped " + item); 5: } 6:  7: // TryPopRange will only pop up to the number of spaces in the array, the actual number popped is returned. 8: var poppedItems = new string[2]; 9: int numPopped = stack.TryPopRange(poppedItems); 10:  11: foreach (var theItem in poppedItems.Take(numPopped)) 12: { 13: Console.WriteLine("Popped " + theItem); 14: } Finally, note that as stated before, GetEnumerator() and ToArray() gets a snapshot of the data at the time of the call.  That means if you are enumerating the stack you will get a snapshot of the stack at the time of the call.  This is illustrated below: 1: var stack = new ConcurrentStack<string>(); 2:  3: // adding to stack is much the same as before 4: stack.Push("First"); 5:  6: var results = stack.GetEnumerator(); 7:  8: // but you can also push multiple items in one atomic operation (no interleaves) 9: stack.PushRange(new [] { "Second", "Third", "Fourth" }); 10:  11: while(results.MoveNext()) 12: { 13: Console.WriteLine("Stack only has: " + results.Current); 14: } The only item that will be printed out in the above code is "First" because the snapshot was taken before the other items were added. This may sound like an issue, but it’s really for safety and is more correct.  You don’t want to enumerate a stack and have half a view of the stack before an update and half a view of the stack after an update, after all.  In addition, note that this is still thread-safe, whereas iterating through a non-concurrent collection while updating it in the old collections would cause an exception. ConcurrentQueue<T>: The thread-safe FIFO container The ConcurrentQueue<T> is the thread-safe counterpart of the System.Collections.Generic.Queue<T> class.  The concurrent queue uses an underlying list of small arrays and lock-free System.Threading.Interlocked operations on the head and tail arrays.  Once again, this allows us to do thread-safe operations without the need for heavy locks! The ConcurrentQueue<T> (like the ConcurrentStack<T>) has some departures from the non-concurrent counterpart.  Most notably: Dequeue() was removed in favor of TryDequeue(). Returns true if an item existed and was dequeued and false if empty. Count does not take a snapshot It subtracts the head and tail index to get the count.  This results overall in a O(1) complexity which is quite good.  It’s still recommended, however, that for empty checks you call IsEmpty instead of comparing Count to zero. ToArray() and GetEnumerator() both take snapshots. This means that iteration over a queue will give you a static view at the time of the call and will not reflect updates. The Enqueue() method on the ConcurrentQueue<T> works much the same as the generic Queue<T>: 1: var queue = new ConcurrentQueue<string>(); 2:  3: // adding to queue is much the same as before 4: queue.Enqueue("First"); 5: queue.Enqueue("Second"); 6: queue.Enqueue("Third"); For front item access, the TryPeek() method must be used to attempt to see the first item if the queue.  There is no Peek() method since, as you’ll remember, we can only peek on a non-empty queue, so we must have an atomic TryPeek() that checks for empty and then returns the first item if the queue is non-empty. 1: // to look at first item in queue without removing it, can use TryPeek. 2: // Note that there is no Peek(), this is because you need to check for empty first. TryPeek does. 3: string item; 4: if (queue.TryPeek(out item)) 5: { 6: Console.WriteLine("First item was " + item); 7: } 8: else 9: { 10: Console.WriteLine("Queue was empty."); 11: } Then, to remove items you use TryDequeue().  Once again this is for the same reason we have TryPeek() and not Peek(): 1: // to remove items, use TryDequeue. If queue is empty returns false. 2: if (queue.TryDequeue(out item)) 3: { 4: Console.WriteLine("Dequeued first item " + item); 5: } Just like the concurrent stack, the ConcurrentQueue<T> takes a snapshot when you call ToArray() or GetEnumerator() which means that subsequent updates to the queue will not be seen when you iterate over the results.  Thus once again the code below will only show the first item, since the other items were added after the snapshot. 1: var queue = new ConcurrentQueue<string>(); 2:  3: // adding to queue is much the same as before 4: queue.Enqueue("First"); 5:  6: var iterator = queue.GetEnumerator(); 7:  8: queue.Enqueue("Second"); 9: queue.Enqueue("Third"); 10:  11: // only shows First 12: while (iterator.MoveNext()) 13: { 14: Console.WriteLine("Dequeued item " + iterator.Current); 15: } Using collections concurrently You’ll notice in the examples above I stuck to using single-threaded examples so as to make them deterministic and the results obvious.  Of course, if we used these collections in a truly multi-threaded way the results would be less deterministic, but would still be thread-safe and with no locking on your part required! For example, say you have an order processor that takes an IEnumerable<Order> and handles each other in a multi-threaded fashion, then groups the responses together in a concurrent collection for aggregation.  This can be done easily with the TPL’s Parallel.ForEach(): 1: public static IEnumerable<OrderResult> ProcessOrders(IEnumerable<Order> orderList) 2: { 3: var proxy = new OrderProxy(); 4: var results = new ConcurrentQueue<OrderResult>(); 5:  6: // notice that we can process all these in parallel and put the results 7: // into our concurrent collection without needing any external locking! 8: Parallel.ForEach(orderList, 9: order => 10: { 11: var result = proxy.PlaceOrder(order); 12:  13: results.Enqueue(result); 14: }); 15:  16: return results; 17: } Summary Obviously, if you do not need multi-threaded safety, you don’t need to use these collections, but when you do need multi-threaded collections these are just the ticket! The plethora of features (I always think of the movie The Three Amigos when I say plethora) built into these containers and the amazing way they acheive thread-safe access in an efficient manner is wonderful to behold. Stay tuned next week where we’ll continue our discussion with the ConcurrentBag<T> and the ConcurrentDictionary<TKey,TValue>. For some excellent information on the performance of the concurrent collections and how they perform compared to a traditional brute-force locking strategy, see this wonderful whitepaper by the Microsoft Parallel Computing Platform team here.   Tweet Technorati Tags: C#,.NET,Concurrent Collections,Collections,Multi-Threading,Little Wonders,BlackRabbitCoder,James Michael Hare

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• MVC Automatic Menu

  - by Nuri Halperin

  An ex-colleague of mine used to call his SQL script generator "Super-Scriptmatic 2000". It impressed our then boss little, but was fun to say and use. We called every batch job and script "something 2000" from that day on. I'm tempted to call this one Menu-Matic 2000, except it's waaaay past 2000. Oh well. The problem: I'm developing a bunch of stuff in MVC. There's no PM to generate mounds of requirements and there's no Ux Architect to create wireframe. During development, things change. Specifically, actions get renamed, moved from controller x to y etc. Well, as the site grows, it becomes a major pain to keep a static menu up to date, because the links change. The HtmlHelper doesn't live up to it's name and provides little help. How do I keep this growing list of pesky little forgotten actions reigned in? The general plan is: Decorate every action you want as a menu item with a custom attribute Reflect out all menu items into a structure at load time Render the menu using as CSS  friendly <ul><li> HTML. The MvcMenuItemAttribute decorates an action, designating it to be included as a menu item: [AttributeUsage(AttributeTargets.Method, AllowMultiple = true)] public class MvcMenuItemAttribute : Attribute {   public string MenuText { get; set; }   public int Order { get; set; }   public string ParentLink { get; set; }   internal string Controller { get; set; }   internal string Action { get; set; }     #region ctor   public MvcMenuItemAttribute(string menuText) : this(menuText, 0) { } public MvcMenuItemAttribute(string menuText, int order) { MenuText = menuText; Order = order; }       internal string Link { get { return string.Format("/{0}/{1}", Controller, this.Action); } }   internal MvcMenuItemAttribute ParentItem { get; set; } #endregion } The MenuText allows overriding the text displayed on the menu. The Order allows the items to be ordered. The ParentLink allows you to make this item a child of another menu item. An example action could then be decorated thusly: [MvcMenuItem("Tracks", Order = 20, ParentLink = "/Session/Index")] . All pretty straightforward methinks. The challenge with menu hierarchy becomes fairly apparent when you try to render a menu and highlight the "current" item or render a breadcrumb control. Both encounter an  ambiguity if you allow a data source to have more than one menu item with the same URL link. The issue is that there is no great way to tell which link a person click. Using referring URL will fail if a user bookmarked the page. Using some extra query string to disambiguate duplicate URLs essentially changes the links, and also ads a chance of collision with other query parameters. Besides, that smells. The stock ASP.Net sitemap provider simply disallows duplicate URLS. I decided not to, and simply pick the first one encountered as the "current". Although it doesn't solve the issue completely – one might say they wanted the second of the 2 links to be "current"- it allows one to include a link twice (home->deals and products->deals etc), and the logic of deciding "current" is easy enough to explain to the customer. Now that we got that out of the way, let's build the menu data structure: public static List<MvcMenuItemAttribute> ListMenuItems(Assembly assembly) { var result = new List<MvcMenuItemAttribute>(); foreach (var type in assembly.GetTypes()) { if (!type.IsSubclassOf(typeof(Controller))) { continue; } foreach (var method in type.GetMethods()) { var items = method.GetCustomAttributes(typeof(MvcMenuItemAttribute), false) as MvcMenuItemAttribute[]; if (items == null) { continue; } foreach (var item in items) { if (String.IsNullOrEmpty(item.Controller)) { item.Controller = type.Name.Substring(0, type.Name.Length - "Controller".Length); } if (String.IsNullOrEmpty(item.Action)) { item.Action = method.Name; } result.Add(item); } } } return result.OrderBy(i => i.Order).ToList(); } Using reflection, the ListMenuItems method takes an assembly (you will hand it your MVC web assembly) and generates a list of menu items. It digs up all the types, and for each one that is an MVC Controller, digs up the methods. Methods decorated with the MvcMenuItemAttribute get plucked and added to the output list. Again, pretty simple. To make the structure hierarchical, a LINQ expression matches up all the items to their parent: public static void RegisterMenuItems(List<MvcMenuItemAttribute> items) { _MenuItems = items; _MenuItems.ForEach(i => i.ParentItem = items.FirstOrDefault(p => String.Equals(p.Link, i.ParentLink, StringComparison.InvariantCultureIgnoreCase))); } The _MenuItems is simply an internal list to keep things around for later rendering. Finally, to package the menu building for easy consumption: public static void RegisterMenuItems(Type mvcApplicationType) { RegisterMenuItems(ListMenuItems(Assembly.GetAssembly(mvcApplicationType))); } To bring this puppy home, a call in Global.asax.cs Application_Start() registers the menu. Notice the ugliness of reflection is tucked away from the innocent developer. All they have to do is call the RegisterMenuItems() and pass in the type of the application. When you use the new project template, global.asax declares a class public class MvcApplication : HttpApplication and that is why the Register call passes in that type. protected void Application_Start() { AreaRegistration.RegisterAllAreas(); RegisterRoutes(RouteTable.Routes);   MvcMenu.RegisterMenuItems(typeof(MvcApplication)); }   What else is left to do? Oh, right, render! public static void ShowMenu(this TextWriter output) { var writer = new HtmlTextWriter(output);   renderHierarchy(writer, _MenuItems, null); }   public static void ShowBreadCrumb(this TextWriter output, Uri currentUri) { var writer = new HtmlTextWriter(output); string currentLink = "/" + currentUri.GetComponents(UriComponents.Path, UriFormat.Unescaped);   var menuItem = _MenuItems.FirstOrDefault(m => m.Link.Equals(currentLink, StringComparison.CurrentCultureIgnoreCase)); if (menuItem != null) { renderBreadCrumb(writer, _MenuItems, menuItem); } }   private static void renderBreadCrumb(HtmlTextWriter writer, List<MvcMenuItemAttribute> menuItems, MvcMenuItemAttribute current) { if (current == null) { return; } var parent = current.ParentItem; renderBreadCrumb(writer, menuItems, parent); writer.Write(current.MenuText); writer.Write(" / ");   }     static void renderHierarchy(HtmlTextWriter writer, List<MvcMenuItemAttribute> hierarchy, MvcMenuItemAttribute root) { if (!hierarchy.Any(i => i.ParentItem == root)) return;   writer.RenderBeginTag(HtmlTextWriterTag.Ul); foreach (var current in hierarchy.Where(element => element.ParentItem == root).OrderBy(i => i.Order)) { if (ItemFilter == null || ItemFilter(current)) {   writer.RenderBeginTag(HtmlTextWriterTag.Li); writer.AddAttribute(HtmlTextWriterAttribute.Href, current.Link); writer.AddAttribute(HtmlTextWriterAttribute.Alt, current.MenuText); writer.RenderBeginTag(HtmlTextWriterTag.A); writer.WriteEncodedText(current.MenuText); writer.RenderEndTag(); // link renderHierarchy(writer, hierarchy, current); writer.RenderEndTag(); // li } } writer.RenderEndTag(); // ul } The ShowMenu method renders the menu out to the provided TextWriter. In previous posts I've discussed my partiality to using well debugged, time test HtmlTextWriter to render HTML rather than writing out angled brackets by hand. In addition, writing out using the actual writer on the actual stream rather than generating string and byte intermediaries (yes, StringBuilder being no exception) disturbs me. To carry out the rendering of an hierarchical menu, the recursive renderHierarchy() is used. You may notice that an ItemFilter is called before rendering each item. I figured that at some point one might want to exclude certain items from the menu based on security role or context or something. That delegate is the hook for such future feature. To carry out rendering of a breadcrumb recursion is used again, this time simply to unwind the parent hierarchy from the leaf node, then rendering on the return from the recursion rather than as we go along deeper. I guess I was stuck in LISP that day.. recursion is fun though.   Now all that is left is some usage! Open your Site.Master or wherever you'd like to place a menu or breadcrumb, and plant one of these calls: <% MvcMenu.ShowBreadCrumb(this.Writer, Request.Url); %> to show a breadcrumb trail (notice lack of "=" after <% and the semicolon). <% MvcMenu.ShowMenu(Writer); %> to show the menu.   As mentioned before, the HTML output is nested <UL> <LI> tags, which should make it easy to style using abundant CSS to produce anything from static horizontal or vertical to dynamic drop-downs.   This has been quite a fun little implementation and I was pleased that the code size remained low. The main crux was figuring out how to pass parent information from the attribute to the hierarchy builder because attributes have restricted parameter types. Once I settled on that implementation, the rest falls into place quite easily.

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• Unity The parameter host could not be resolved when attempting to call constructor

  - by Terrance

  When I attempt to instantiate my instance of the base class I get the error: a ResolutionFailedException with roughly the following error "The parameter host could not be resolved when attempting to call constructor" I'm currently not using an Interface for the base type and my instance of the class is inheriting the base type class. I'm new to Unity and DI so I'm thinking its something I forgot possibly. ExeConfigurationFileMap map = new ExeConfigurationFileMap(); map.ExeConfigFilename = "Unity.Config"; Configuration config = ConfigurationManager.OpenMappedExeConfiguration(map, ConfigurationUserLevel.None); UnityConfigurationSection section = (UnityConfigurationSection)config.GetSection("unity"); IUnityContainer container = new UnityContainer(); section.Containers.Default.Configure(container); //Throws exception here on this BaseCalculatorServer server = container.Resolve<BaseCalculatorServer>(); and the Unity.Config file <container> <types> <type name ="CalculatorServer" type="Calculator.Logic.BaseCalculatorServer, Calculator.Logic" mapTo="Calculator.Logic.CalculateApi, Calculator.Logic"/> </types> </container> </containers> The Base class using System; using System.Collections.Generic; using System.Linq; using System.Text; using System.Runtime.Serialization; using System.ServiceModel; using System.ServiceModel.Transactions; using Microsoft.Practices.Unity; using Calculator.Logic; namespace Calculator.Logic { public class BaseCalculatorServer : IDisposable { public BaseCalculatorServer(){} public CalculateDelegate Calculate { get; set; } public CalculationHistoryDelegate CalculationHistory { get; set; } /// <summary> /// Performs application-defined tasks associated with freeing, releasing, or resetting unmanaged resources. /// </summary> public void Dispose() { this.Dispose(); } } } The Implementation using System; using System.Collections.Generic; using System.Linq; using System.Text; using Calculator.Logic; using System.ServiceModel; using System.ServiceModel.Configuration; using Microsoft.Practices.Unity; namespace Calculator.Logic { public class CalculateApi:BaseCalculatorServer { public CalculateApi(ServiceHost host) { host.Open(); Console.WriteLine("Press Enter To Exit"); Console.ReadLine(); host.Close(); } public CalculateDelegate Calculate { get; set; } public CalculationHistoryDelegate CalculationHistory { get; set; } } } Yes both base class and implementation are in the same Namespace and thats something design wise that will change once I get this working. Oh and a more detailed error Resolution of the dependency failed, type = "Calculator.Logic.BaseCalculatorServer", name = "". Exception message is: The current build operation (build key Build Key[Calculator.Logic.BaseCalculatorServer, null]) failed: The value for the property "Calculate" could not be resolved. (Strategy type BuildPlanStrategy, index 3)

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• Duplication in parallel inheritance hierarchies

  - by flamingpenguin

  Using an OO language with static typing (like Java), what are good ways to represent the following model invariant without large amounts of duplication. I have two (actually multiple) flavours of the same structure. Each flavour requires its own (unique to that flavour data) on each of the objects within that structure as well as some shared data. But within each instance of the aggregation only objects of one (the same) flavour are allowed. FooContainer can contain FooSources and FooDestinations and associations between the "Foo" objects BarContainer can contain BarSources and BarDestinations and associations between the "Bar" objects interface Container() { List<? extends Source> sources(); List<? extends Destination> destinations(); List<? extends Associations> associations(); } interface FooContainer() extends Container { List<? extends FooSource> sources(); List<? extends FooDestination> destinations(); List<? extends FooAssociations> associations(); } interface BarContainer() extends Container { List<? extends BarSource> sources(); List<? extends BarDestination> destinations(); List<? extends BarAssociations> associations(); } interface Source { String getSourceDetail1(); } interface FooSource extends Source { String getSourceDetail2(); } interface BarSource extends Source { String getSourceDetail3(); } interface Destination { String getDestinationDetail1(); } interface FooDestination extends Destination { String getDestinationDetail2(); } interface BarDestination extends Destination { String getDestinationDetail3(); } interface Association { Source getSource(); Destination getDestination(); } interface FooAssociation extends Association { FooSource getSource(); FooDestination getDestination(); String getFooAssociationDetail(); } interface BarAssociation extends Association { BarSource getSource(); BarDestination getDestination(); String getBarAssociationDetail(); }

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• C#/.NET Little Wonders: The ConcurrentDictionary

  - by James Michael Hare

  Once again we consider some of the lesser known classes and keywords of C#.  In this series of posts, we will discuss how the concurrent collections have been developed to help alleviate these multi-threading concerns.  Last week’s post began with a general introduction and discussed the ConcurrentStack<T> and ConcurrentQueue<T>.  Today's post discusses the ConcurrentDictionary<T> (originally I had intended to discuss ConcurrentBag this week as well, but ConcurrentDictionary had enough information to create a very full post on its own!).  Finally next week, we shall close with a discussion of the ConcurrentBag<T> and BlockingCollection<T>. For more of the "Little Wonders" posts, see the index here. Recap As you'll recall from the previous post, the original collections were object-based containers that accomplished synchronization through a Synchronized member.  While these were convenient because you didn't have to worry about writing your own synchronization logic, they were a bit too finely grained and if you needed to perform multiple operations under one lock, the automatic synchronization didn't buy much. With the advent of .NET 2.0, the original collections were succeeded by the generic collections which are fully type-safe, but eschew automatic synchronization.  This cuts both ways in that you have a lot more control as a developer over when and how fine-grained you want to synchronize, but on the other hand if you just want simple synchronization it creates more work. With .NET 4.0, we get the best of both worlds in generic collections.  A new breed of collections was born called the concurrent collections in the System.Collections.Concurrent namespace.  These amazing collections are fine-tuned to have best overall performance for situations requiring concurrent access.  They are not meant to replace the generic collections, but to simply be an alternative to creating your own locking mechanisms. Among those concurrent collections were the ConcurrentStack<T> and ConcurrentQueue<T> which provide classic LIFO and FIFO collections with a concurrent twist.  As we saw, some of the traditional methods that required calls to be made in a certain order (like checking for not IsEmpty before calling Pop()) were replaced in favor of an umbrella operation that combined both under one lock (like TryPop()). Now, let's take a look at the next in our series of concurrent collections!For some excellent information on the performance of the concurrent collections and how they perform compared to a traditional brute-force locking strategy, see this wonderful whitepaper by the Microsoft Parallel Computing Platform team here. ConcurrentDictionary – the fully thread-safe dictionary The ConcurrentDictionary<TKey,TValue> is the thread-safe counterpart to the generic Dictionary<TKey, TValue> collection.  Obviously, both are designed for quick – O(1) – lookups of data based on a key.  If you think of algorithms where you need lightning fast lookups of data and don’t care whether the data is maintained in any particular ordering or not, the unsorted dictionaries are generally the best way to go. Note: as a side note, there are sorted implementations of IDictionary, namely SortedDictionary and SortedList which are stored as an ordered tree and a ordered list respectively.  While these are not as fast as the non-sorted dictionaries – they are O(log2 n) – they are a great combination of both speed and ordering -- and still greatly outperform a linear search. Now, once again keep in mind that if all you need to do is load a collection once and then allow multi-threaded reading you do not need any locking.  Examples of this tend to be situations where you load a lookup or translation table once at program start, then keep it in memory for read-only reference.  In such cases locking is completely non-productive. However, most of the time when we need a concurrent dictionary we are interleaving both reads and updates.  This is where the ConcurrentDictionary really shines!  It achieves its thread-safety with no common lock to improve efficiency.  It actually uses a series of locks to provide concurrent updates, and has lockless reads!  This means that the ConcurrentDictionary gets even more efficient the higher the ratio of reads-to-writes you have. ConcurrentDictionary and Dictionary differences For the most part, the ConcurrentDictionary<TKey,TValue> behaves like it’s Dictionary<TKey,TValue> counterpart with a few differences.  Some notable examples of which are: Add() does not exist in the concurrent dictionary. This means you must use TryAdd(), AddOrUpdate(), or GetOrAdd().  It also means that you can’t use a collection initializer with the concurrent dictionary. TryAdd() replaced Add() to attempt atomic, safe adds. Because Add() only succeeds if the item doesn’t already exist, we need an atomic operation to check if the item exists, and if not add it while still under an atomic lock. TryUpdate() was added to attempt atomic, safe updates. If we want to update an item, we must make sure it exists first and that the original value is what we expected it to be.  If all these are true, we can update the item under one atomic step. TryRemove() was added to attempt atomic, safe removes. To safely attempt to remove a value we need to see if the key exists first, this checks for existence and removes under an atomic lock. AddOrUpdate() was added to attempt an thread-safe “upsert”. There are many times where you want to insert into a dictionary if the key doesn’t exist, or update the value if it does.  This allows you to make a thread-safe add-or-update. GetOrAdd() was added to attempt an thread-safe query/insert. Sometimes, you want to query for whether an item exists in the cache, and if it doesn’t insert a starting value for it.  This allows you to get the value if it exists and insert if not. Count, Keys, Values properties take a snapshot of the dictionary. Accessing these properties may interfere with add and update performance and should be used with caution. ToArray() returns a static snapshot of the dictionary. That is, the dictionary is locked, and then copied to an array as a O(n) operation.  GetEnumerator() is thread-safe and efficient, but allows dirty reads. Because reads require no locking, you can safely iterate over the contents of the dictionary.  The only downside is that, depending on timing, you may get dirty reads. Dirty reads during iteration The last point on GetEnumerator() bears some explanation.  Picture a scenario in which you call GetEnumerator() (or iterate using a foreach, etc.) and then, during that iteration the dictionary gets updated.  This may not sound like a big deal, but it can lead to inconsistent results if used incorrectly.  The problem is that items you already iterated over that are updated a split second after don’t show the update, but items that you iterate over that were updated a split second before do show the update.  Thus you may get a combination of items that are “stale” because you iterated before the update, and “fresh” because they were updated after GetEnumerator() but before the iteration reached them. Let’s illustrate with an example, let’s say you load up a concurrent dictionary like this: 1: // load up a dictionary. 2: var dictionary = new ConcurrentDictionary<string, int>(); 3:  4: dictionary["A"] = 1; 5: dictionary["B"] = 2; 6: dictionary["C"] = 3; 7: dictionary["D"] = 4; 8: dictionary["E"] = 5; 9: dictionary["F"] = 6; Then you have one task (using the wonderful TPL!) to iterate using dirty reads: 1: // attempt iteration in a separate thread 2: var iterationTask = new Task(() => 3: { 4: // iterates using a dirty read 5: foreach (var pair in dictionary) 6: { 7: Console.WriteLine(pair.Key + ":" + pair.Value); 8: } 9: }); And one task to attempt updates in a separate thread (probably): 1: // attempt updates in a separate thread 2: var updateTask = new Task(() => 3: { 4: // iterates, and updates the value by one 5: foreach (var pair in dictionary) 6: { 7: dictionary[pair.Key] = pair.Value + 1; 8: } 9: }); Now that we’ve done this, we can fire up both tasks and wait for them to complete: 1: // start both tasks 2: updateTask.Start(); 3: iterationTask.Start(); 4:  5: // wait for both to complete. 6: Task.WaitAll(updateTask, iterationTask); Now, if I you didn’t know about the dirty reads, you may have expected to see the iteration before the updates (such as A:1, B:2, C:3, D:4, E:5, F:6).  However, because the reads are dirty, we will quite possibly get a combination of some updated, some original.  My own run netted this result: 1: F:6 2: E:6 3: D:5 4: C:4 5: B:3 6: A:2 Note that, of course, iteration is not in order because ConcurrentDictionary, like Dictionary, is unordered.  Also note that both E and F show the value 6.  This is because the output task reached F before the update, but the updates for the rest of the items occurred before their output (probably because console output is very slow, comparatively). If we want to always guarantee that we will get a consistent snapshot to iterate over (that is, at the point we ask for it we see precisely what is in the dictionary and no subsequent updates during iteration), we should iterate over a call to ToArray() instead: 1: // attempt iteration in a separate thread 2: var iterationTask = new Task(() => 3: { 4: // iterates using a dirty read 5: foreach (var pair in dictionary.ToArray()) 6: { 7: Console.WriteLine(pair.Key + ":" + pair.Value); 8: } 9: }); The atomic Try…() methods As you can imagine TryAdd() and TryRemove() have few surprises.  Both first check the existence of the item to determine if it can be added or removed based on whether or not the key currently exists in the dictionary: 1: // try add attempts an add and returns false if it already exists 2: if (dictionary.TryAdd("G", 7)) 3: Console.WriteLine("G did not exist, now inserted with 7"); 4: else 5: Console.WriteLine("G already existed, insert failed."); TryRemove() also has the virtue of returning the value portion of the removed entry matching the given key: 1: // attempt to remove the value, if it exists it is removed and the original is returned 2: int removedValue; 3: if (dictionary.TryRemove("C", out removedValue)) 4: Console.WriteLine("Removed C and its value was " + removedValue); 5: else 6: Console.WriteLine("C did not exist, remove failed."); Now TryUpdate() is an interesting creature.  You might think from it’s name that TryUpdate() first checks for an item’s existence, and then updates if the item exists, otherwise it returns false.  Well, note quite... It turns out when you call TryUpdate() on a concurrent dictionary, you pass it not only the new value you want it to have, but also the value you expected it to have before the update.  If the item exists in the dictionary, and it has the value you expected, it will update it to the new value atomically and return true.  If the item is not in the dictionary or does not have the value you expected, it is not modified and false is returned. 1: // attempt to update the value, if it exists and if it has the expected original value 2: if (dictionary.TryUpdate("G", 42, 7)) 3: Console.WriteLine("G existed and was 7, now it's 42."); 4: else 5: Console.WriteLine("G either didn't exist, or wasn't 7."); The composite Add methods The ConcurrentDictionary also has composite add methods that can be used to perform updates and gets, with an add if the item is not existing at the time of the update or get. The first of these, AddOrUpdate(), allows you to add a new item to the dictionary if it doesn’t exist, or update the existing item if it does.  For example, let’s say you are creating a dictionary of counts of stock ticker symbols you’ve subscribed to from a market data feed: 1: public sealed class SubscriptionManager 2: { 3: private readonly ConcurrentDictionary<string, int> _subscriptions = new ConcurrentDictionary<string, int>(); 4:  5: // adds a new subscription, or increments the count of the existing one. 6: public void AddSubscription(string tickerKey) 7: { 8: // add a new subscription with count of 1, or update existing count by 1 if exists 9: var resultCount = _subscriptions.AddOrUpdate(tickerKey, 1, (symbol, count) => count + 1); 10:  11: // now check the result to see if we just incremented the count, or inserted first count 12: if (resultCount == 1) 13: { 14: // subscribe to symbol... 15: } 16: } 17: } Notice the update value factory Func delegate.  If the key does not exist in the dictionary, the add value is used (in this case 1 representing the first subscription for this symbol), but if the key already exists, it passes the key and current value to the update delegate which computes the new value to be stored in the dictionary.  The return result of this operation is the value used (in our case: 1 if added, existing value + 1 if updated). Likewise, the GetOrAdd() allows you to attempt to retrieve a value from the dictionary, and if the value does not currently exist in the dictionary it will insert a value.  This can be handy in cases where perhaps you wish to cache data, and thus you would query the cache to see if the item exists, and if it doesn’t you would put the item into the cache for the first time: 1: public sealed class PriceCache 2: { 3: private readonly ConcurrentDictionary<string, double> _cache = new ConcurrentDictionary<string, double>(); 4:  5: // adds a new subscription, or increments the count of the existing one. 6: public double QueryPrice(string tickerKey) 7: { 8: // check for the price in the cache, if it doesn't exist it will call the delegate to create value. 9: return _cache.GetOrAdd(tickerKey, symbol => GetCurrentPrice(symbol)); 10: } 11:  12: private double GetCurrentPrice(string tickerKey) 13: { 14: // do code to calculate actual true price. 15: } 16: } There are other variations of these two methods which vary whether a value is provided or a factory delegate, but otherwise they work much the same. Oddities with the composite Add methods The AddOrUpdate() and GetOrAdd() methods are totally thread-safe, on this you may rely, but they are not atomic.  It is important to note that the methods that use delegates execute those delegates outside of the lock.  This was done intentionally so that a user delegate (of which the ConcurrentDictionary has no control of course) does not take too long and lock out other threads. This is not necessarily an issue, per se, but it is something you must consider in your design.  The main thing to consider is that your delegate may get called to generate an item, but that item may not be the one returned!  Consider this scenario: A calls GetOrAdd and sees that the key does not currently exist, so it calls the delegate.  Now thread B also calls GetOrAdd and also sees that the key does not currently exist, and for whatever reason in this race condition it’s delegate completes first and it adds its new value to the dictionary.  Now A is done and goes to get the lock, and now sees that the item now exists.  In this case even though it called the delegate to create the item, it will pitch it because an item arrived between the time it attempted to create one and it attempted to add it. Let’s illustrate, assume this totally contrived example program which has a dictionary of char to int.  And in this dictionary we want to store a char and it’s ordinal (that is, A = 1, B = 2, etc).  So for our value generator, we will simply increment the previous value in a thread-safe way (perhaps using Interlocked): 1: public static class Program 2: { 3: private static int _nextNumber = 0; 4:  5: // the holder of the char to ordinal 6: private static ConcurrentDictionary<char, int> _dictionary 7: = new ConcurrentDictionary<char, int>(); 8:  9: // get the next id value 10: public static int NextId 11: { 12: get { return Interlocked.Increment(ref _nextNumber); } 13: } Then, we add a method that will perform our insert: 1: public static void Inserter() 2: { 3: for (int i = 0; i < 26; i++) 4: { 5: _dictionary.GetOrAdd((char)('A' + i), key => NextId); 6: } 7: } Finally, we run our test by starting two tasks to do this work and get the results… 1: public static void Main() 2: { 3: // 3 tasks attempting to get/insert 4: var tasks = new List<Task> 5: { 6: new Task(Inserter), 7: new Task(Inserter) 8: }; 9:  10: tasks.ForEach(t => t.Start()); 11: Task.WaitAll(tasks.ToArray()); 12:  13: foreach (var pair in _dictionary.OrderBy(p => p.Key)) 14: { 15: Console.WriteLine(pair.Key + ":" + pair.Value); 16: } 17: } If you run this with only one task, you get the expected A:1, B:2, ..., Z:26.  But running this in parallel you will get something a bit more complex.  My run netted these results: 1: A:1 2: B:3 3: C:4 4: D:5 5: E:6 6: F:7 7: G:8 8: H:9 9: I:10 10: J:11 11: K:12 12: L:13 13: M:14 14: N:15 15: O:16 16: P:17 17: Q:18 18: R:19 19: S:20 20: T:21 21: U:22 22: V:23 23: W:24 24: X:25 25: Y:26 26: Z:27 Notice that B is 3?  This is most likely because both threads attempted to call GetOrAdd() at roughly the same time and both saw that B did not exist, thus they both called the generator and one thread got back 2 and the other got back 3.  However, only one of those threads can get the lock at a time for the actual insert, and thus the one that generated the 3 won and the 3 was inserted and the 2 got discarded.  This is why on these methods your factory delegates should be careful not to have any logic that would be unsafe if the value they generate will be pitched in favor of another item generated at roughly the same time.  As such, it is probably a good idea to keep those generators as stateless as possible. Summary The ConcurrentDictionary is a very efficient and thread-safe version of the Dictionary generic collection.  It has all the benefits of type-safety that it’s generic collection counterpart does, and in addition is extremely efficient especially when there are more reads than writes concurrently. Tweet Technorati Tags: C#, .NET, Concurrent Collections, Collections, Little Wonders, Black Rabbit Coder,James Michael Hare

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