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• Ideal way to deliver large data over Web Services

  - by zengr

  We are trying to design 6 web services, which will serve another client component. The client component requires data from the web service we are implementing. Now, the problem is, there is not 1 WS we are implementing, there is one WS which the client component hits, this initiates a series (5 more) of WSs which gather data from their respective data stores and finally provide the data back to the original WS, which then delivers the data back to the client component. So, if the requested data becomes huge, then, this will be a serious problem for our internal communication channel. So, what do you guys suggest? What can be done to avoid overloading of the communication channel between the internal WS and at the same time, also delivering the data to the client component.

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• Does DB2 have an "insert or update" statement?

  - by Mikael Eriksson

  From my code (Java) I want to ensure that a row exists in the database (DB2) after my code is executed. My code now does a select and if no result is returned it does an insert. I really don't like this code since it exposes me to concurrency issuses when running in a multi-threaded environment. What I would like to do is to put this logic in DB2 instead of in my Java code. Does DB2 have an "insert-or-update" statement? Or anything like it that I can use? For example: insertupdate into mytable values ('myid') Another way of doing it would probably be to allways do the insert and catch "SQL-code -803 primary key already exists", but I would like to avoid that if possible.

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• Explanation for expires header

  - by sushil bharwani

  I have a joomla application working on Apache.To improve site performace we have written a .htaccess file to root of the application with setting a far future expires header to all the static content. As desired first time the files load in fresh with 200 status code. when again click on the same link many of the files are served directly from cache. I need explanation for two things When i press f5 then a number of files load with 304 status code however i expected them to be coming directly from cache without hitting the server for a status header? When i close the browser and come back to the same page again i see the same thing happening a number of files load with 304 status code although i thought they will load directly from the browser cache? I understand that 304 also servs file from browser cache but i want to avoid the header communication between servers as my static files wont ever change. Also i want to add that my requests are over a https connection does that create any issue.

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• Showing Live Wallpaper in a 1.6 target app by detecting if it's a 2.1 device?

  - by itamarw

  We're building an Android app with target SDK 1.6, so it will run on 1.6 devices and higher. We'd like to support Live Wallpapers, which we know is 2.1+ only. Is there a way to build one app with 1.6 SDK as the target, but detect if the device it's running on is 2.1, and only in that scenario call the live wallpaper API. We're trying to avoid having to build a separate 1.6 and 2.1 versions, and would like to be able to support Live Wallpapers for only 2.1 devices. So to be clear- 1 app, that can support 1.6 and higher, and support live wallpapers for 2.1 devices. Any way of doing this?

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• explicit copy constructor or implicit parameter by value

  - by R Samuel Klatchko

  I recently read (and unfortunately forgot where), that the best way to write operator= is like this: foo &operator=(foo other) { swap(*this, other); return *this; } instead of this: foo &operator=(const foo &other) { foo copy(other); swap(*this, copy); return *this; } The idea is that if operator= is called with an rvalue, the first version can optimize away construction of a copy. So when called with a rvalue, the first version is faster and when called with an lvalue the two are equivalent. I'm curious as to what other people think about this? Would people avoid the first version because of lack of explicitness? Am I correct that the first version can be better and can never be worse?

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• How to make an invisible button to run a command

  - by Denis Mitropolskiy

  I have a form with TextBox and two Buttons. One button has IsDefault property set to true, and IsCancel set to true for other button. TextBox is CommandTarget for both buttons. When I'm pressing Enter or ESC keys on TextBox, it works as I'm pressing on corresponding button. I want to remove buttons from the form. They should not be visible, but the textbox should react on Enter or ESC as before. I cannot just set button's Visible property to collapsed - in this case they does not work at all. And I prefer to avoid of tracking keyboard events. Is it possible?

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• How to remove duplication from RSpec

  - by Asa

  context "answer is correct" do before(:each) do @answer = stub_model(Answer, :correct => true).as_new_record assigns[:answer] = @answer render "answers/summarize" end it "should display flashcard context properly" do response.should contain("Quiz") end it "should summarize results" do response.should contain("is correct") end end context "answer is incorrect" do before(:each) do @answer = stub_model(Answer, :correct => false).as_new_record assigns[:answer] = @answer render "answers/summarize" end it "should display flashcard context properly" do response.should contain("Quiz") end it "should summarize results" do response.should contain("is incorrect") end end How do I avoid repeating the following block within both of the above contexts? it "should display flashcard context properly" do response.should contain("Quiz") end

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• Multiple levels of 'collection.defaultdict' in Python

  - by Morlock

  Thanks to some great folks on SO, I discovered the possibilities offered by collections.defaultdict, notably in readability and speed. I have put them to use with success. Now I would like to implement three levels of dictionaries, the two top ones being defaultdict and the lowest one being int. I don't find the appropriate way to do this. Here is my attempt: from collections import defaultdict d = defaultdict(defaultdict) a = [("key1", {"a1":22, "a2":33}), ("key2", {"a1":32, "a2":55}), ("key3", {"a1":43, "a2":44})] for i in a: d[i[0]] = i[1] Now this works, but the following, which is the desired behavior, doesn't: d["key4"]["a1"] + 1 I suspect that I should have declared somewhere that the second level defaultdict is of type int, but I didn't find where or how to do so. The reason I am using defaultdict in the first place is to avoid having to initialize the dictionary for each new key. Any more elegant suggestion? Thanks pythoneers!

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• Complicated idea - how to create car racing for my RPG game's players

  - by Donator

  So, I want to create car racing for my RPG game's players. Player can create race and choose how many participants can participate in race. After race is being created, other people can join it. When the maximum participants are collected, race begins. My idea, when the last participant joins, then instantly choose the winner (who's car is the best, that person wins), but how can I do it? If I choose to pick the winner after the last participant joins, then I have to put many queries in one page (select data from table, then delete the race, then select players' cars' statistics and pick the winner and then again, using mysql, send message to everyone). But this idea is really not optimal and it will lag cruelly for that last person. Maybe you have any ideas how I can avoid lag and make it more optimal. Thank you very much.

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• Does JavaME and/or Proguard reorder assignments?

  - by chrisdew

  This is a simplified example - I have two threads: Can JavaME and/Proguard ever reorder the obX = ... statements, such that thread_B will have a null pointer exception at ob2.someMethod? thread_A: Object ob1 = null; Object ob2 = null; ... ob1 = something1; ob2 = something2; thread_B: if (ob2 != null) { ob1.someMethod(); ... } P.S. I do realise that synchronising these will avoid the issue. Synchronisation has both a performance overhead, and more importantly, a chance to introduce deadlock.

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• TableAdapter to return ONLY selected columns? (VS2008)

  - by MattSlay

  (VS2008) I'm trying to configure a TableAdapter in a Typed DataSet to return only a certain subset of columns from the main schema of the table on which it is based, but it always returns the entire schema (all columns) with blank values in the columns I have omitted. The TableAdpater has the default Fill and GetData() methods that come from the wizard, which contain every column in the table, which is fine. I then added a new parameterized query method called GetActiveJobsByCustNo(CustNo), and I only included a few columns in the SQL query that I actually want to be in this table view. But, again, it returns all the columns in the master table schema, with empty values for the columns I omitted. The reason I am wanting this, is so I can just get a few columns back to use that table view with AutoGenerateColumns in an ASP.NET GridView. With it giving me back EVERY column i nthe schema, my presentation GridView contains way more columns that I want to show th user. And, I want to avoid have to declare the columns in the GridView.

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• Development deployment: how to achive edit-and-reload with JSP pages?

  - by doublep

  Out project uses WebLogic as web-server and uses mostly JSP for user interface. With standard setup it is possible to copy edited JSP files into the exploded deployment directory and WebLogic will automatically pick them up, recompile and serve new content through HTTP. However, is it possible to avoid copying at all, so that I just save a file in my editor and it is immediately (well, after a couple of seconds for recompilation) visible? The project uses Apache Ant as building tool. I would imagine what I want would be possible with symlinks (since this is for deployment only I don't care about cross-platformity), but then I don't see how it is possible to symlink lots of files at once with Ant. So, how do I achieve save-JSP-hit-F5-in-browser functionality either with some setting in WebLogic; or with symlinking JSPs using Apache Ant (instead of copying them as is done now); or something else completely?

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• Spring MVC; avoiding file extension in url?

  - by Ezombort

  I just started with Spring Web MVC. I'm trying to avoid file extenstions in the url. How can i do this? (I'm using Spring 2.5.x) Bean: <bean name="/hello.htm" class="springapp.web.HelloController"/> I want it to be: <bean name="/hello" class="springapp.web.HelloController"/> I cannot get it to work. Any ideas? Edit: Url-mapping <servlet-mapping> <servlet-name>springapp</servlet-name> <url-pattern>*.htm</url-pattern> </servlet-mapping> I have tried changing the url-pattern with no luck (* and /*).

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• T-SQL out of order insert

  - by tearman

  Basically I have a User-Defined Table Type (for use as a table-valued variable) which I'm referencing in a stored procedure that effectively just calls two other stored procedures, then inserts those values into the table type. Id est INSERT INTO @tableValuedVariable (var1, var2, var3, var4, var5) EXEC [dbo].StoredProcedure1; INSERT INTO @tableValuedVariable (var1, var2, var5) EXEC [dbo].StoredProcedure2; You can probably already tell what I'm going to ask. Basically StoredProcedure2 only returns a few of the values the table is set to hold, and I'd like those other variables to just be null (as defined as default). Only SQL is complaining that I'm not specifying all the variables available to that table. The return datasets can be quite sizable so I'd like to avoid loops and such for obvious reasons. Thanks for any help.

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• Using an EJB inside a JAX-RS resource class in RestEasy?

  - by Laird Nelson

  I would like to have the following kind of resource class work when deployed under RestEasy in JBoss 6: @Path("Something") public class Foo { @EJB private SomeService service @GET public Object frobnicate() { assert service != null; // JBoss blows up here return result; } } Two questions: It is a limitation of RestEasy, not of the Java EE specification, right, that RestEasy can't inject anything annotated with @EJB? What have people done to work around this limitation? My developers are about to surge forward with hard-coded JNDI lookups (e.g. context.lookup(someHardCodedNameHere)) because no one can find a workaround to this specification violation at the present time. I really want to avoid this. Lastly, I've looked at using CDI, but the story here isn't much better as RestEasy and CDI still aren't talking to each other. Thanks in advance for any pointers.

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• Visual Studio 2008 adding incorrect working folders to TFS Workspace

  - by Bryan Rowe

  I am using Visual Studio 2008 with TFS. I have one workspace set up with one working folder. I map the root source control folder $/ to C:\TFS and get all code. When working on any project under the root, Visual Studio will randomly add incorrectly mapped working folders to my workspace. For example, it might map $/WebProject/ to C:\TFS\WebProject\DataAccess -- where the real files exist at C:\TFS\WebProject. Once it incorrectly adds these working folders, I can no longer open the solution. I am forced to remove the working folders that Visual Studio added and get latest from TFS. Has anyone experienced this? Is there something I can do to avoid running into this?

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• How to find good looking font color if background color is known?

  - by Mecki

  There seem to be so many color wheel, color picker, and color matcher web apps out there, where you give one color and the they'll find a couple of other colors that will create a harmonic layout when being used in combination. However most of them focus on background colors only and any text printed on each background color (if text is printed at all in the preview) is either black or white. My problem is different. I know the background color I want to use for a text area. What I need help with is choosing a couple of colors (the more, the merrier) I can use as font colors on this background. Most important is that the color will make sure the font is readable (contrast not being too low, also maybe not being too high to avoid that eyes are stressed) and of course that the combination of foreground and background just looks good. Anyone being aware of such an application? I'd prefer a web application to anything I have to download. Thanks.

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• Easily switching ConnectionStrings on publish to Azure

  - by David Pfeffer

  I'm currently building an Azure Web Role. I am testing this project against a local database server on localhost. Then, when confident that the project is working, I publish it to Staging on Windows Azure. However, I also have to remember to change the connection string to point to the live SQL server on SQL Azure before deploying, and then change it back to localhost afterwards. Is there any nice way to automate this, or perhaps a different process to take to avoid the issue altogether? For example is there a way to have a configuration file for Azure that isn't updated with every deploy?

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• Static Access To Multiple Instance Variable

  - by Qua

  I have a singleton instance that is referenced throughout the project which works like a charm. It saves me the trouble from having to pass around an instance of the object to every little class in the project. However, now I need to manage multiple instances of the previous setup, which means that the singleton pattern breaks since each instance would need it's own singleton instance. What options are there to still maintain static access to the singleton? To be more specific, we have our game engine and several components and plugins reference the engine through a static property. Now our server needs to host multiple game instances each having their own engine, which means that on the server side the singleton pattern breaks. I'm trying to avoid all the classes having the engine in the constructor.

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• Automatically deleting pyc files when corresponding py is moved (Mercurial)

  - by Oddthinking

  (I foresaw this problem might happen 3 months ago, and was told to be diligent to avoid it. Yesterday, I was bitten by it, hard, and now that it has cost me real money, I am keen to fix it.) If I move one of my Python source files into another directory, I need to remember to tell Mercurial that it moved (hg move). When I deploy the new software to my server with Mercurial, it carefully deletes the old Python file and creates it in the new directory. However, Mercurial is unaware of the pyc file in the same directory, and leaves it behind. The old pyc is used preferentially over new python file by other modules in the same directory. What ensues is NOT hilarity. How can I persuade Mercurial to automatically delete my old pyc file when I move the python file? Is there another better practice? Trying to remember to delete the pyc file from all the Mercurial repositories isn't working.

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• polymorphic hql

  - by Berryl

  I have a base type where "business id" must be unique for a given subclass, but it is possible for there to be different subclasses with the same business id. If there is a base type with a requested id but of the wrong subclass I want to return null, using a named query. The code below does this, but I am wondering if I can avoid the try/catch with a better HQL. Can I? Cheers, Berryl current hql <query name="FindActivitySubjectByBusinessId"> <![CDATA[ from ActivitySubject act where act.BusinessId = :businessId ]]> </query> current fetch code public ActivitySubject FindByBusinessId<T>(string businessId) where T : ActivitySubject { Check.RequireStringValue(businessId, "businessId"); try { return _session.GetNamedQuery("FindActivitySubjectByBusinessId") .SetString("businessId", businessId) .UniqueResult<T>(); } catch (InvalidCastException e) { // an Activity Subject was found with the requested id but the wrong type return null; } }

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• Copying (or recovering) a .PFX password to another machine?

  - by Adam Robinson

  First things first, I'm aware of all of the finger-wagging potential that this question provides. However, I'm attempting to help out a friend with a project so I haven't been part of the decision making process thus far. I'm attempting to set up a new development machine, but one of the projects is signed with a .PFX key that's password protected and the original developer does not remember the password. The current development machine can open and build the project just fine, so I'm wondering if there is any way either to copy or to recover the saved password that Visual Studio is using on the original box so that the file can be used on the new box. Signing with a new file is obviously an option, but one that we'd prefer to avoid. Does anyone know of a way either to recover or copy the credentials for this file to a new machine?

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• Actionscript 3 : XML cached in local testing

  - by Boun

  Hi, My question is about XML loading. I need to avoid xml caching. On a web server, the technique is adding a random param to reload each time the XML file. But on local testing (in Flash CS4 IDE, CTRL + Enter), the following lines are not possible : var my_date : Date; path = "toto.xml?time="+my_date.getSeconds()+my_date.getMilliseconds(); Is there any trick to bypass this issue ? I've read on different forum about the "delete" method, we delete the xml object and then recreate one new. In my case, I put : myXML = null; myXML = new XML ( loadedData ); But it doesn't work at all. I spent many hours on that problem, if anyone has a good solution... Thank you.

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• Using Accelerometer in Wiimote for Physics Practicals

  - by Omar

  I have to develop some software in my school to utilize the accelerometer in the Wiimote for recording data from experiments, for example finding the acceleration and velocity of a moving object. I understand how the accelerometer values will be used but I am sort of stuck on the programming front. There is a set of things that I would like to do: Live streaming of data from the Wiimote via bluetooth Use the accelerometer values to find velocity and displacment via integration Plot a set of results Avoid the use of the infrared sensor on the Wiimote Please can anyone give me their thoughts on how to go about this. Also it would be great if people could direct me to existing projects that utizlise the wiimote. Also can someone suggest what would be the best programming language to use for this. My current bet is on using Visual basic. Any sort of help is greatly appretiated.

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• NDIS or TDI for packet redirection to a local proxy

  - by Enrico Detoma

  I need to develop a transparent filter to redirect outgoing HTTP packets to a local proxy, to do transparent content filtering. Which is the best technology to do it, TDI or NDIS IM? My main constraint is to avoid conflicts with antivirus software, which also do some kind of packet redirection to inspect HTTP content (I don't know whether antivirus programs use TDI, NDIS IM, or both). Rather than writing the driver myself, actually, I'm also considering two commercial SDKs for packet filtering/modification: one uses a TDI driver while the other uses a NDIS IM driver, so that's the origin of my question (I was only aware of NDIS IM, before looking at the two SDKs).

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