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• URL with no query parameters - How to distinguish.

  - by Broken Link

  Env: .NET 1.1 I got into this situation. Where I need to give a URL that someone could redirect them to our page. When they redirect they also need to tell us, what message I need to display on the page. Initially I thought of something like this. http://example.com/a.aspx?reason=100 http://example.com/a.aspx?reason=101 ... http://example.com/a.aspx?reason=115 So when we get this url based on 'reason' we can display different message. But the problem turns out to be that they can not send any query parameters at all. They want 15 difference URL's since they can't send query params. It doesn't make any sense to me to created 15 pages just to display a message. Any smart ideas,that have one URL and pass the 'reason' thru some means? EDIT: Options I'm thinking based on Answers Try HttpRequest.PathInfo or Second option I was thinking was to have a httphanlder read read the path like this - HttpContext.Request.Path based on path act. Ofcourse I will have some 15 entries like this in web.config. <add verb="*" path="reason1.ashx" type="WebApplication1.Class1, WebApplication1" /> <add verb="*" path="reason2.ashx" type="WebApplication1.Class1, WebApplication1" /> Does that look clean?

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• Requested operation requires an OLE DB Session object... - Connecting Excel to SQL server via ADO

  - by Frank V

  I'm attempting to take Excel 2003 and connect it to SQL Server 2000 to run a few dynamicly generated SQL Queries which ultimately filling certain cells. I'm attempting to do this via VBA via ADO (I've tried 2.8 to 2.0) but I'm getting an error while setting the ActiveConnection variable which is inside the ADODB.Connection object. I need to resolve this pretty quick... Requested operation requires an OLE DB Session object, which is not supported by the current provider. I'm honestly not sure what this error means and right now I don't care. How can get this connection to succeed so that I can run my queries? Here is my VB code: Dim SQL As String, RetValue As String SQL = " select top 1 DateTimeValue from SrcTable where x='value' " 'Not the real SQL RetValue = "" Dim RS As ADODB.Recordset Dim Con As New ADODB.Connection Dim Cmd As New ADODB.Command Con.ConnectionString = "Provider=sqloledb;DRIVER=SQL Server;Data Source=Server\Instance;Initial Catalog=MyDB_DC;User Id=<UserName>;Password=<Password>;" Con.CommandTimeout = (60 * 30) Set Cmd.ActiveConnection = Con ''Error occurs here. ' I'm not sure if the rest is right. I've just coded it. Can't get past the line above. Cmd.CommandText = SQL Cmd.CommandType = adCmdText Con.Open Set RS = Cmd.Execute() If Not RS.EOF Then RetValue = RS(0).Value Debug.Print "RetValue is: " & RetValue End If Con.Close I imagine something is wrong with the connection string but I've tried over a dozen variations. Now I'm just shooting in the dark.... Note/Update: To make matters more confusing, if I Google for the error quote above, I get a lot of hits back but nothing seems relevant or I'm not sure what information is relevant.... I've got the VBA code in "Sheet1" under "Microsoft Excel Objects." I've done this before but usually put things in a module. Could this make a difference?

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• How much effort do you have to put in to get gains from using SSE?

  - by John

  Case One Say you have a little class: class Point3D { private: float x,y,z; public: operator+=() ...etc }; Point3D &Point3D::operator+=(Point3D &other) { this->x += other.x; this->y += other.y; this->z += other.z; } A naive use of SSE would simply replace these function bodies with using a few intrinsics. But would we expect this to make much difference? MMX used to involve costly state cahnges IIRC, does SSE or are they just like other instructions? And even if there's no direct "use SSE" overhead, would moving the values into SSE registers and back out again really make it any faster? Case Two Instead, you're working with a less OO-based code base. Rather than an array/vector of Point3D objects, you simply have a big array of floats: float coordinateData[NUM_POINTS*3]; void add(int i,int j) //yes it's unsafe, no overlap check... example only { for (int x=0;x<3;++x) { coordinateData[i*3+x] += coordinateData[j*3+x]; } } What about use of SSE here? Any better? In conclusion Is trying to optimise single vector operations using SSE actually worthwhile, or is it really only valuable when doing bulk operations?

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• New Rails deployment half working...not sure why?

  - by Meltemi

  I'm in the final stages of going round trip through the entire Rails cycle: development - test - production (on an external server). I'm very close...but seeing some errors with the production version and don't know enough about Rails' "magic" to troubleshoot it yet... all seems well and I can load my app by going to www.mydomain.com/rails and it seems to work...I can interact with my app and create new objects in my database. However, when I go to www.mydomain.com/rails/ (difference is the trailing slash) i get a webpage that just says "Index from public" on it?!? I don't know where that's coming from? index.html is long removed from public. this may or may not be related to why I can't access, say, the first record in one of my classes by calling its controller like so: www.mydomain.com/rails/mycontroller/1 . and yes, there are records in the database. anyway, something's askew. it works fine on development box. but, only half working on production server. anyone know what might be causing this? this app is running on the server box (not development) Installed Passenger on server to serve app via Apache modified my httpd.conf with Passenger's stuff (headache but finally got it to respond) loaded schema into the production database: rake db:schema:load RAILS_ENV=production

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• Problem with setVisible (true)

  - by Jessy

  The two examples shown below are same. Both are supposed to produce same result e.g. generate the coordinates of images displayed on JPanel. Example 1, works perfectly (print the coordinates of images), however example 2 returning 0 for the coordinate. I was wondering why because, I have put the setvisible (true) after adding the panel, in both examples. The only difference is that example 1 used extends JPanel and example 2 extends JFrame EXAMPLE 1: public class Grid extends JPanel{ public static void main(String[] args){ JFrame jf=new JFrame(); jf.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); final Grid grid = new Grid(); jf.add(grid); jf.pack(); Component[] components = grid.getComponents(); for (Component component : components) { System.out.println("Coordinate: "+ component.getBounds()); } jf.setVisible(true); } } EXAMPLE 2: public class Grid extends JFrame { public Grid () { setLayout(new GridBagLayout()); GridBagLayout m = new GridBagLayout(); Container c = getContentPane(); c.setLayout (m); GridBagConstraints con = new GridBagConstraints(); //construct the JPanel pDraw = new JPanel(); ... m.setConstraints(pDraw, con); pDraw.add (new GetCoordinate ()); // call new class to generate the coordinate c.add(pDraw); pack(); setVisible(true); } public static void main(String[] args) { new Grid(); } }

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• _dl_runtime_resolve -- When do the shared objects get loaded in to memory?

  - by windfinder

  We have a message processing system with high performance demands. Recently we have noticed that the first message takes many times longer then subsequent messages. A bunch of transformation and message augmentation happens as this goes through our system, much of it done by way of external lib. I just profiled this issue (using callgrind), comparing a "run" of just one message with a "run" of many messages (providing a baseline of comparison). The main difference I see is the function "do_lookup_x" taking up a huge amount of time. Looking at the various calls to this function, they all seem to be called by the common function: _dl_runtime_resolve. Not sure what this function does, but to me this looks like the first time the various shared libraries are being used, and are then being loaded in to memory by the ld. Is this a correct assumption? That the binary will not load the shared libraries in to memory until they are being prepped for use, therefore we will see a massive slowdown on the first message, but on none of the subsequent? How do we go about avoiding this? Note: We operate on the microsecond scale.

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• Long-held TCP sessions in an ASMX client

  - by John

  Hi, I have an ASP.NET application which talks to a third-party SOAP web service. My application uses an ASMX client proxy (i.e. System.Web.Services.Protocols.SoapHttpClientProtocol). The third-party service uses WCF, although I don't expect that makes much difference. I should note that we're using .NET 3.5 SP1. We haven't customised the proxy or done anything unusual - we're just making standard web service requests and getting back the results. We have encapsulated the proxy reference within a using block so it will get disposed after the response is received. We've been told that our application is behaving strangely in its use of TCP sessions. Instead of opening a new TCP session for each request from a new proxy instance (which is what I would have expected it to do), it's apparently keeping several connections alive and re-using them. This is causing some issues at the third party end, as they are expecting us to be using multiple sessions. Is this a known behaviour for the SoapHttpClientProtocol client proxy? If so, is there any way we can override it so that each request results in a new TCP session? Thanks, John

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• Auto-implemented getters and setters vs. public fields

  - by tclem

  I see a lot of example code for C# classes that does this: public class Point { public int x { get; set; } public int y { get; set; } } Or, in older code, the same with an explicit private backing value and without the new auto-implemented properties: public class Point { private int _x; private int _y; public int x { get { return _x; } set { _x = value; } } public int y { get { return _y; } set { _y = value; } } } My question is why. Is there any functional difference between doing the above and just making these members public fields, like below? public class Point { public int x; public int y; } To be clear, I understand the value of getters and setters when you need to do some translation of the underlying data. But in cases where you're just passing the values through, it seems needlessly verbose.

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• rails validation of presence not failing on nil

  - by holden

  I want to make sure an attibute exists, but it seems to still slip thru and I'm not sure how better to check for it. This should work, but doesn't. It's a attr_accessor and not a real attribute if that makes a difference. validates_presence_of :confirmed, :rooms {"commit"=>"Make Booking", "place_id"=>"the-kosmonaut", "authenticity_token"=>"Tkd9bfGqYFfYUv0n/Kqp6psXHjLU7CmX+D4UnCWMiMk=", "utf8"=>"✓", "booking"=>{"place_id"=>"6933", "bookdate"=>"2010-11-22", "rooms"=>[{}], "no_days"=>"2"}} Not sure why my form_for returns a blank hash in an array... <% form_for :booking, :url => place_bookings_path(@place) do |f| %> <%= f.hidden_field :bookdate, { :value => user_cart.getDate } %> <%= f.hidden_field :no_days, { :value => user_cart.getDays } %> <% for room in pricing_table(@place.rooms,@valid_dates) %> <%= select_tag("booking[rooms][][#{room.id}]", available_beds(room)) %> <% end %> <% end %>

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• How can I pass a const array or a variable array to a function in C?

  - by CSharperWithJava

  I have a simple function Bar that uses a set of values from a data set that is passed in in the form of an Array of data structures. The data can come from two sources: a constant initialized array of default values, or a dynamically updated cache. The calling function determines which data is used and should be passed to Bar. Bar doesn't need to edit any of the data and in fact should never do so. How should I declare Bar's data parameter so that I can provide data from either set? union Foo { long _long; int _int; } static const Foo DEFAULTS[8] = {1,10,100,1000,10000,100000,1000000,10000000}; static Foo Cache[8] = {0}; void Bar(Foo* dataSet, int len);//example function prototype Note, this is C, NOT C++ if that makes a difference; Edit Oh, one more thing. When I use the example prototype I get a type qualifier mismatch warning, (because I'm passing a mutable reference to a const array?). What do I have to change for that?

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• NSUserDefaults: Saved Number Always 0, iPhone

  - by Stumf

  Hello all, I have looked at other answers and the docs. Maybe I am missing something, or maybe I have another issue. I am trying to save a number on exiting the app, and then when the app is loaded I want to check if this value exists and take action accordingly. This is what I have tried: To save on exiting: - (void)applicationWillTerminate: (UIApplication *) application { double save = [label.text doubleValue]; [[NSUserDefaults standardUserDefaults] setDouble: save forKey: @"savedNumber"]; [[NSUserDefaults standardUserDefaults] synchronize]; } To check: - (IBAction)buttonclickSkip{ double save = [[NSUserDefaults standardUserDefaults] doubleForKey: @"savedNumber"]; if (save == 0) { [self performSelector:@selector(displayAlert) withObject:nil]; test.enabled = YES; test.alpha = 1.0; skip.enabled = NO; skip.alpha = 0.0; } else { label.text = [NSString stringWithFormat:@"%.1f %%", save]; } } The problem is I always get my alert message displayed, the saved value is not put into the label so somehow == 0 is always true. If it makes any difference I am testing this on the iPhone simulator. Many thanks, Stu

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• Having trouble with confusing behaviour of error between debug and release modes in Xcode

  - by Cocorico

  Hi guys, I am confused over something (what is new!). I have an iPhone program I am writing and using some sqlite in a certain method, and there is some error which is giving me a message that says "Program received signal: “EXC_BAD_ACCESS” Okay, so I am trying to hunt down why this is doing this, and I notice something: When I run the program in debug mode, it gives me this error every single time I access this method (I test on the device). However when I run the program in release mode, I can access this method 2 times, and then it will give me this error the third time. So I mean, can someone just give me an explanation of what might cause this, I think that maybe deep-down I am not that smart on the difference in XCode of debug and release modes. I think that release mode does optimizing, and I guess the actual assembly machine code comes out different, yes? I AM A BIG NEWBIE USER UNFORTUNATELY! I am not clear on a lot of things like this, or whether it needs for I to remove nslog commands in the release build and such. Maybe I should just post the actual code in separate Stack OVerflow post, and see if people can see the error, then maybe this all become clear to me.

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• Same jQuery code returns two different results – Submit Button Text

  - by Lijo

  I have two jQuery codes - http://jsfiddle.net/Lijo/CXGX7/7/ and http://jsfiddle.net/Lijo/CXGX7/8/ . The first code returns undefined whereas the second code returns text of button. QUESTIONS What is the reason for this difference in result? Why is the first code not returning expected text of button? Note: I verified that both are using same version of jQuery (by an alert of jQuery) alert($.fn.jquery); CODE <html xmlns="http://www.w3.org/1999/xhtml"> <head><title> </title> <script type="text/javascript" src="http://ajax.aspnetcdn.com/ajax/jquery/jquery-1.8.1.js"></script> <script type="text/javascript"> alert($('.myButton').attr("value")); </script> </head> <body> <form method="post" action="Test.aspx" id="form1"> <div class="aspNetHidden"> <input type="hidden" name="__VIEWSTATE" id="__VIEWSTATE" value="/wEPDwULLTE0MDM4MzYxMjNkZMycQvsYQ+GPFsQHoQ8j/8vEo2vQbqkhfgPc60kxXaQO" /> </div> <div class="aspNetHidden"> <input type="hidden" name="__EVENTVALIDATION" id="__EVENTVALIDATION" value="/wEWAwKqxqqrCgLi/JazDQKM54rGBqgaroRQTXJkD1LyUlVxAmLRCNfTGVe73swQBMemBtvN" /> </div> <div> <input name="txtEmpName" type="text" id="txtEmpName" /> <input type="submit" name="Button1" value="Submit" id="Button1" class="myButton" /> </div> </form> </body> </html> REFERENCES Retrieve Button value with jQuery How to determine and print jQuery version?

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• Arrow keys and changing control's focus hang the application

  - by sthay

  I have a usercontrol that contains a FlowLayoutPanel (topdown flow) with a bunch of radiobuttons. The control exposes a CheckedChanged event that fires whenever one of the radiobuttons's check changed. My form contains the usercontrol and a textbox. I subscribe the usercontrol's CheckedChanged event and depending on which radiobutton gets checked, I either disable the textbox or put a focus inside the textbox. All this works fine with mouseclick when changing the radiobutton's check state. However, this will hang indefinitely when using the arrow keys. I don't understand why the difference. The following are steps to reproduce the behavior I'm seeing: Create a usercontrol and drop a FlowLayoutPanel control and set its FlowDirection = TopDown. Then add two radiobuttons to the FlowLayoutPanel. Provide an event handler in the usercontrol public event EventHandler CheckedChanged { add { radioButton2.CheckedChanged += value; } remove { radioButton2.CheckedChanged -= value; } } Create a windows form and drop the above user control. Add a textbox and set Enabled to False. Subscribe to the usercontrol's CheckedChanged event as follows private void userControl11_CheckedChanged(object sender, EventArgs e) { textBox1.Select(); } Run. Notice that if you use the mouse to click between the radiobuttons, thing works fine; but it will crash if you use the up/down arrow keys.

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• Performance: float to int cast and clipping result to range

  - by durandai

  I'm doing some audio processing with float. The result needs to be converted back to PCM samples, and I noticed that the cast from float to int is surprisingly expensive. Whats furthermore frustrating that I need to clip the result to the range of a short (-32768 to 32767). While I would normally instictively assume that this could be assured by simply casting float to short, this fails miserably in Java, since on the bytecode level it results in F2I followed by I2S. So instead of a simple: int sample = (short) flotVal; I needed to resort to this ugly sequence: int sample = (int) floatVal; if (sample > 32767) { sample = 32767; } else if (sample < -32768) { sample = -32768; } Is there a faster way to do this? (about ~6% of the total runtime seems to be spent on casting, while 6% seem to be not that much at first glance, its astounding when I consider that the processing part involves a good chunk of matrix multiplications and IDCT) EDIT The cast/clipping code above is (not surprisingly) in the body of a loop that reads float values from a float[] and puts them into a byte[]. I have a test suite that measures total runtime on several test cases (processing about 200MB of raw audio data). The 6% were concluded from the runtime difference when the cast assignment "int sample = (int) floatVal" was replaced by assigning the loop index to sample. EDIT @leopoldkot: I'm aware of the truncation in Java, as stated in the original question (F2I, I2S bytecode sequence). I only tried the cast to short because I assumed that Java had an F2S bytecode, which it unfortunately does not (comming originally from an 68K assembly background, where a simple "fmove.w FP0, D0" would have done exactly what I wanted).

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• Initializing objects on the fly

  - by pocoa

  I have a vector called players and a class called Player. And what I'm trying to do is to write: players.push_back(Player(name, Weapon(bullets))); So I want to be able to create players in a loop. But I see an error message says "no matching function for call Player::Player..." Then I've changed that to: Weapon w(bullets); Player p(name, w); players.push_back(p); Here is my Player definition: class Player { public: Player(string &name, Weapon &weapon); private string name; Weapon weapon; } I'm just trying to learn what is the difference between these definitions. And is this the right way to pass an object to an object constructor. Note: These are not my actual class definitions. I'm just trying to learn something about object oriented programming in C++ with coding it. I mean I know that Weapon should be initialized in Player :)

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• Oracle DBMS_PROFILER only shows Anonymous in the results tables

  - by Greg Reynolds

  I am new to DBMS_PROFILER. All the examples I have seen use a simple top-level procedure to demonstrate the use of the profiler, and from there get all the line numbers etc. I deploy all code in packages, and I am having great difficulty getting my profile session to populate the plsql_profiler_units with useful data. Most of my runs look like this: RUNID RUN_COMMENT UNIT_OWNER UNIT_NAME SECS PERCEN ----- ----------- ----------- -------------- ------- ------ 5 Test <anonymous> <anonymous> .00 2.1 Profiler 5 Test <anonymous> <anonymous> .00 2.1 Profiler 5 Test <anonymous> <anonymous> .00 2.1 Profiler I have just embedded the calls to the dbms_profiler.start_profiler, flush_data and stop_profiler as per all the examples. The main difference is that my code is in a package, and calls in to other package. Do you have to profile every single stored procedure in your call stack? If so that makes this tool a little useless! I have checked http://www.dba-oracle.com/t_plsql_dbms_profiler.htm for hints, among other similar sites.

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• ImageButton OnClick Event not firing

  - by webnoob

  Hi All, I am really confused about this one. I have some code that runs fine on my development server but I am now trying to get the site working on the sales guys new laptop. None of the image buttons on the website seem to be working for him (they just redirect me back to the websites homepage) whereas they used to on his previous machine. The only difference between each machine is that his old one was Vista and the new one is Windows 7. Has anyone come accross this issue? Some code: The form: <div class="form_text"></div> <div class="form_box_link"> <asp:ImageButton id="LoginSubmitButton" onClick="FLoginWebService" ImageURL="~/Images/login.png" runat="server" /> </div> The code behind (delphi): procedure TMemberLogin.FLoginWebService(Sender: TObject; e: System.EventArgs); begin //Code Removed but using OutputDebugString shows nothing is being done in here end; As mentioned, this works everywhere else except on his windows 7 machine.

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• how to access anti aliasing method of a font with CSS

  - by Daniel Ramirez-Escudero

  I've had this problem in a lot of different webs. You have a font which has different anti-aliasing options, the designer uses the same font with different anti-aliasing options on different parts of the text on the web. So there is a difference between some elements. In this case I have sharp, crisp, strong and smooth. I've used a font generator to get the code to access it via @font-face. Even so, I also have the original .otf if important to know. Is there a method to access this? I upload a picture of what I mean and my actual code: ![@font-face { font-family: 'light'; src: url('../_fnt/light/gothamrnd-light.eot'); src: url('../_fnt/light/gothamrnd-light.eot?#iefix') format('embedded-opentype'), url('../_fnt/light/gothamrnd-light.woff') format('woff'), url('../_fnt/light/gothamrnd-light.ttf') format('truetype'), url('../_fnt/light/gothamrnd-light.svg#../_fnt/light/gothamrnd-light') format('svg'); font-weight: normal; font-style: normal; }]![enter image description here][1]

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• Persistant Http client connections in java

  - by Akusete

  I am trying to write a simple Http client application in Java and am a bit confused by the seemingly different ways to establish Http client connections, and efficiently re-use the objects. Current I am using the following steps (I have left out exception handling for simplicity) Iterator<URI> uriIterator = someURIs(); HttpClient client = new DefaultHttpClient(); while (uriIterator.hasNext()) { URI uri = uriIterator.next(); HttpGet request = new HttpGet(uri); HttpResponse response = client.execute(request); HttpEntity entity = response.getEntity(); InputStream s = entity.getContent(); processStream (); s.close(); } In regard to the code above, my questions is: Assuming all URI's are pointing to the same host (but different resources on that host). What is the recommended way to use a single http connection for all requests? And how do you close the connection after the last request? --edit: Also what is the difference between using uri.openConnection(), versus HttpClient? Which is preferable, and what other methods exist?

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• How to interpolate in MatLab

  - by G Sam

  I have a 1x1 Matrix of points which specifies speed of a drive with respect to time. This speed changes throughout the operation; which means that the difference between two points is changing. To give you an example: M = [1; 2; 3; 5; 7; 9; 11; 15; 19]. (Only that this is a 892x1 matrix) I want to make this matrix twice as long (so changing the relative speed per timestep), while retaining the way the speeds change. Eg: M' = [1; 1.5; 2; 2.5; 3; 4; 5; 6; 7; 8; 9; 10; 11; 13; 15; 17; 19]. Is there an easy way to do this in MatLab? So far I have tried upsampling (which fills the time step with zeros); interp (which fills it with low-pass interpolation. Thanks!

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• Calling services from the Orchestrating layer in SOA?

  - by Martin Lee

  The Service Oriented Architecture Principles site says that Service Composition is an important thing in SOA. But Service Loose Coupling is important as well. Does that mean that the "Orchestrating layer" should be the only one that is allowed to make calls to services in the system? As I understand SOA, the "Orchestrating layer" 'glues' all the services together into one software application. I tried to depict that on Fig.A and Fig.B. The difference between the two is that on Fig.A the application is composed of services and all the logic is done in the "Orchestrating layer" (all calls to services are done from the "Orchestrating layer" only). On Fig.B the application is composed from services, but one service calls another service. Does the architecture on Fig.B violate the "Service Loose Coupling" principle of SOA? Can a service call another service in SOA? And more generally, can the architecture on Fig.A be considered superior to the one on Fig.B in terms of service loose coupling, abstraction, reusability, autonomy, etc.? My guess is that the A architecture is much more universal, but it can add some unnecessary data transfers between the "Orchestrating layer" and all the called services.

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• Why ntp settle time toe long?

  - by fercis

  I simply try to set-up NTP to my system. Both server and clients will run on my computer which are linked together with local link. One of them will have the reference clock. Both the server and Client are linux Ubuntu. I install ntp daemon to both sides. In clients, I enter the ip address of the server to /etc/ntp.conf. Everything works fine. However, the setting of the time to correct time in client side takes too long time (around 17 minutes). Is it possible to gather correct time just at startup. I write some code that regularly calls "ntpdate " by system call and the problem is solved but there has to be something that allows me to decrease the poll time of the client to 1-2 minutes. There are some settings as maxpoll - minpoll in ntp.conf, but I couldn't manage to understand their function, because with the best configuration (minpoll 4? 16 seconds?) I also cannot see that client side corrects its time before 10 minutes. In addition, in some cases my client is an embedded system (ARM - IGEP board) and it always opens with an irrelevant date (2-3 years ago). So the time that takes to correct the time should not depend on the time difference also.

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• Java try finally variations

  - by Petr Gladkikh

  This question nags me for a while but I did not found complete answer to it yet (e.g. this one is for C# http://stackoverflow.com/questions/463029/initializing-disposable-resources-outside-or-inside-try-finally). Consider two following Java code fragments: Closeable in = new FileInputStream("data.txt"); try { doSomething(in); } finally { in.close(); } and second variation Closeable in = null; try { in = new FileInputStream("data.txt"); doSomething(in); } finally { if (null != in) in.close(); } The part that worries me is that the thread might be somewhat interrupted between the moment resource is acquired (e.g. file is opened) but resulting value is not assigned to respective local variable. Is there any other scenarios the thread might be interrupted in the point above other than: InterruptedException (e.g. via Thread#interrupt()) or OutOfMemoryError exception is thrown JVM exits (e.g. via kill, System.exit()) Hardware fail (or bug in JVM for complete list :) I have read that second approach is somewhat more "idiomatic" but IMO in the scenario above there's no difference and in all other scenarios they are equal. So the question: What are the differences between the two? Which should I prefer if I do concerned about freeing resources (especially in heavily multi-threading applications)? Why? I would appreciate if anyone points me to parts of Java/JVM specs that support the answers.

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• OpenCL - incremental summation during compute

  - by user1721997

  I'm absolutelly novice in OpenCL programming. For my app. (molecular simulaton) I wrote a kernel for calculate intermolecular potential of lennard-jones liquid. In this kernel I need to compute cumulative value of the potential of all particles with one: __kernel void Molsim(__global const float* inmatrix, __global float* fi, const int c, const float r1, const float r2, const float r3, const float rc, const float epsilon, const float sigma, const float h1, const float h23) { float fi0; float fi1; float d; unsigned int i = get_global_id(0); //number of particles (typically 2000) if(c!=i) { // potential before particle movement d=sqrt(pow((0.5*h1-fabs(0.5*h1-fabs(inmatrix[c*3]-inmatrix[i*3]))),2.0)+pow((0.5*h23-fabs(0.5*h23-fabs(inmatrix[c*3+1]-inmatrix[i*3+1]))),2.0)+pow((0.5*h23-fabs(0.5*h23-fabs(inmatrix[c*3+2]-inmatrix[i*3+2]))),2.0)); if(d<rc) { fi0=4.0*epsilon*(pow(sigma/d,12.0)-pow(sigma/d,6.0)); } else { fi0=0; } // potential after particle movement d=sqrt(pow((0.5*h1-fabs(0.5*h1-fabs(r1-inmatrix[i*3]))),2.0)+pow((0.5*h23-fabs(0.5*h23-fabs(r2-inmatrix[i*3+1]))),2.0)+pow((0.5*h23-fabs(0.5*h23-fabs(r3-inmatrix[i*3+2]))),2.0)); if(d<rc) { fi1=4.0*epsilon*(pow(sigma/d,12.0)-pow(sigma/d,6.0)); } else { fi1=0; } // cumulative difference of potentials fi[0]+=fi1-fi0; } } My problem is in the line: fi[0]+=fi1-fi0;. In the one-element vector fi[0] are wrong results. I read something about sum reduction, but I do not know how to do it during the calculation. Exist any simple solution of my problem?

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