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• Correct way to detect sequence parameter?

  - by noamtm

  I want to write a function that accepts a parameter which can be either a sequence or a single value. The type of value is str, int, etc., but I don't want it to be restricted to a hardcoded list. In other words, I want to know if the parameter X is a sequence or something I have to convert to a sequence to avoid special-casing later. I could do type(X) in (list, tuple) but there may be other sequence types I'm not aware of, and no common base class. -N. Edit: See my "answer" below for why most of these answers don't help me. Maybe you have something better to suggest.

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• Communication between Page and User Controls

  - by Narmatha Balasundaram

  I have a main page that has multiple user controls on it. All the user controls have static text and some data to be retrieved from the DB. The aysnchronous DB call is clubbed at the page level and one call is made to avoid multiple calls (in the different user controls) to get the same data. I want the page and user controls to load initially with the static text and later refresh the contents obtained from the server. To sum it all up, Page Loads = Asyn calls fired on page load = Data received back from the server (XML/text/whatever) = User controls to load with this data using AJAX. What methods do I have to let the user controls know that I have the data from the server and they need to update with this data?

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• Struts2 dynamic form elements

  - by bozo

  Hi, I would like to create little higer-level framework on top of Stuts2 which can take form element description from Action and render a complete form, in order to avoid having a separate JSP files with hardcoded form elements for every form in a large web application (so if I manage to do this I will have just a few generic JSPs for data form and few for layout). Application is extremely data-driven. My idea is to create form description using custom objects in the Action (i.e. Button, TextInput etc.) and then to create a single JSP page that will render eveything out. What is the best way of doing this? Can you propose some concrete way to do this? I don't want to write something if I can reuse the existing code with some effort. Any ideas are appreciated. Kind regards, Bozo

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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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• When is JavaScript's eval() not evil?

  - by Richard Turner

  I'm writing some JavaScript to parse user-entered functions (for spreadsheet-like functionality). Having parsed the formula I could convert it into JavaScript and run eval() on it to yield the result. However, I've always shied away from using eval() if I can avoid it because it's evil (and, rightly or wrongly, I've always thought it is even more evil in JavaScript because the code to be evaluated might be changed by the user). Obviously one has to use eval() to parse JSON (I presume that JS libraries use eval() for this somewhere, even if they run the JSON through a regex check first), but when else, other than when manipulating JSON, it is OK to use eval()?

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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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• Model Binding an IList of selected items only

  - by jeef3

  I have an action method setup: public ActionResult Delete(IList<Product> products) And a table of products in my view. I have got Model Binding working so that on submit I can populate the products list. But I would like to populate it with only the products that are selected via a checkbox. I think I could do it by changing the action method to this: public ActionResult Delete(IList<Product> products, IList<int> toDelete) And passing the list of check boxes to the toDelete but I would really like to avoid changing the method signature if possible. Is there a way to pass only the selected items? Or am I going to have to write a custom ModelBinder?

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• Opposite of Bloom filter?

  - by abc

  Hi, I'm trying to optimize a piece of software which is basically running millions of tests. These tests are generated in such a way that there can be some repetitions. Of course, I don't want to spend time running tests which I already ran if I can avoid it efficiently. So, I'm thinking about using a Bloom filter to store the tests which have been already ran. However, the Bloom filter errs on the unsafe side for me. It gives false positives. That is, it may report that I've ran a test which I haven't. Although this could be acceptable in the scenario I'm working on, I was wondering if there's an equivalent to a Bloom filter, but erring on the opposite side, that is, only giving false negatives. I've skimmed through the literature without any luck.

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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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• iPhone+Quartz+OpenGL. What is the correct way for Quartz and OpenGL to play nice together regarding

  - by dugla

  So we know the CoreGraphics/Quartz imaging model is based on pre-multiplied alpha. We also know that OpenGL blending is based on un-premultiplied alpha. What is the best practice to avoid head explosion when doing blending with textures that are derived from pre-multiplied alpha imagery (PNG files generated in Photoshop with pre-multiplied alpha). Given the apples/oranges mish mash of Quartz and OpenGL, what is the correct glBlendFunc for doing the fundamental Porter/Duff "over" operation? Typical example: A simple paint program. Brush shapes are texture-map patterns created from pre-multiplied alpha rgba images. Paint color is specified via glColor4(...) with the alpha channel used to control paint transparency. GL_MODULATE is used so the brush texture multiplies the (translucent) paint color to blend the color into the canvas. Problem: The texture is premult. The color is not. What is the correct way to handle this fundamental inconsistency? Thanks, Doug

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• What are the common programming mistakes in Python?

  - by Paul McGuire

  I was about to tag the recent question in which the OP accidentally shadowed the builtin operator module with his own local operator.py with the "common-mistakes" tag, and I saw that there are a number of interesting questions posted asking for common mistakes to avoid in Java, Ruby, Scala, Clojure, .Net, jQuery, Haskell, SQL, ColdFusion, and so on, but I didn't see any for Python. For the benefit of Python beginners, can we enumerate the common mistakes that we have all committed at one time or another, in the hopes of maybe steering a newbie or two clear of them? (In homage to "The Princess Bride", I call these the Classic Blunders.) If possible, a little supporting explanation on what the problem is, and the generally accepted resolution/workaround, so that the beginning Pythoner doesn't read your answer and say "ok, that's a mistake, how do I fix it?"

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• What is the main purpose and sense to have staging server the same as production?

  - by truthseeker

  Hi, In our company we have staging and production servers. I'm trying to have them in state 1:1 after latest release. We've got web application running on several host and many instances of it. The issue is that I am an advocate of having the same architecture (structure) of web applications on staging and production servers to easily test new features and avoid creating of new bugs with new releases. But not everyone agree with me, and for them is not a such big deal to have different connection between staging application instances. Even maybe to have more application and connections between application on staging than on production server. I would like to ask about pros and cons of such an approach? I mean some good points to agree with me, or some bad why maybe i don't have right. Some examples of consequences and so forth.

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• jquery checked checkbox IE problem

  - by lidermin

  Hi, I'm having an issue verifying if a checkbox is checked using jquery on Internet Explorer. This is the code I'm using: if ($('#chkjq_1').attr('checked') == true) It works fine on Firefox or Chrome, but on Internet Explorer 7, the condition is always false because the browser sets the property this way: <input id="chkjq_1" type="checkbox" CHECKED/> IE7 And the right way is the following: (Firefox, Chrome): <input id="chkjq_1" type="checkbox" checked="checked"/> FF, Chrome, etc What should I do to avoid this issue on Internet Explorer 7; is there a generic way in jquery to solve this? Thanks in advance.

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• How to compile a program which needs a newer version of glib

  - by michael

  Hi, I am trying to compile Webkit on Ubuntu 8.04. But when i run autogen.sh, I get the following error saying it needs a newer version of glib. So what is the safest way to install glib without screwing up the rest of my OS (since the rest needs 2.16 while webkit compile needs 2.21)? checking for GLIB... configure: error: Package requirements (glib-2.0 >= 2.21.3 gobject-2.0 >= 2.0 gthread-2.0 >= 2.0) were not met: Requested 'glib-2.0 >= 2.21.3' but version of GLib is 2.16.6 Consider adjusting the PKG_CONFIG_PATH environment variable if you installed software in a non-standard prefix. Alternatively, you may set the environment variables GLIB_CFLAGS and GLIB_LIBS to avoid the need to call pkg-config. See the pkg-config man page for more details.

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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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• Optimize code perfromance when odd/even threads are doing different things in CUDA

  - by Ashraf

  Hi all! I have two large vectors, I am trying to do some sort of element multiplication, where an even-numbered element in the first vector is multiplied by the next odd-numbered element in the second vector .... and where the odd-numbered element in the first vector is multiplied by the preceding even-numbered element in the second vector Ex. vector 1 is V1(1) V1(2) V1(3) V1(4) vector 2 is V2(1) V2(2) V2(3) V2(4) V1(1) * V2(2) V1(3) * V2(4) V1(2) * V2(1) V1(4) * V2(3) I have written a Cuda code to do this: (Pds has the elements of the first vector in shared memory, Nds the second Vector) //instead of using %2 .. i check for the first bit to decide if number is odd/even -- faster if ((tx & 0x0001) == 0x0000) Nds[tx+1] = Pds[tx] * Nds[tx+1]; else Nds[tx-1] = Pds[tx] * Nds[tx-1]; __syncthreads(); Is there anyway to further accelerate this code or avoid divergence .. Thanks

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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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• 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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• 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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• Python UTF-16 encoding hex representation

  - by Romeno

  I have a string in Python 2.7.2 say u"\u0638". When I write it to file: f = open("J:\\111.txt", "w+") f.write(u"\u0638".encode('utf-16')) f.close() In hex it looks like: FF FE 38 06 When i print such a string to stdout i will see: '\xff\xfe8\x06'. The querstion: Where is \x38 in the string output to stdout? In other words why the string output to stdout is not '\xff\xfe\x38\x06'? If I write the string to file twice: f = open("J:\\111.txt", "w+") f.write(u"\u0638".encode('utf-16')) f.write(u"\u0638".encode('utf-16')) f.close() The hex representation in file contains byte order mark (BOM) \xff\xfe twice: FF FE 38 06 FF FE 38 06 I wonder what is the techique to avoid writting BOM in UTF-16 encoded strings?

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• MySQL: Blank row in table after LOAD DATA INFILE

  - by Tom

  Hi, I'm uploading a large amount of data from a CSV (I'm doing it via MySQL Workbench): LOAD DATA INFILE 'C:/development/mydoc.csv' INTO TABLE mydatabase.mytable CHARACTER SET utf8 FIELDS TERMINATED BY ',' OPTIONALLY ENCLOSED BY '"' LINES TERMINATED BY '\r'; However, I'm noticing that it keeps adding an empty line full of nulls/zeros after the last record. I'm guessing it's because of the "LINES TERMINATED" command. However, I need that to load the data in correctly. Is there some way around this / some better SQL to avoid the blank row in the table? Thanks

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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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• Resolving patch conflicts manually

  - by Antony Hatchkins

  I've downloaded a patch from some site and trying to apply it (twisted, python web framework). Several hunks failed. How do I automate manual patching process using vim? Details: I'm trying to automate the process of applying failed hunks. Many tiny changes, each about adding/removing 1-2 chars. Difficult to see. I Have to create two new temporary files and :diffthis them manually to see the difference. Yes, outside VCS. I can imagine a neat way to deal with it using git, but I would prefer to avoid creating git repo for that.

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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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• Sharepoint: Is it possible to automate the deployment of a custom CAS policy?

  - by user332133

  Hi all, I'm looking for a way to automate the deployment of a custom CAS policy in SharePoint. What i would like to achieve is the following: All assemblies that have been built and signed by our build server (with a secret key) should run in SharePoint under the 'higher than normal' trust level. Now I can manually edit the cas policy files to include something like this: <CodeGroup class="UnionCodeGroup" version="1" PermissionSetName="MyPermissionSet" Name="[My Company public key]" Description="Grants all "> <IMembershipCondition class="StrongNameMembershipCondition" version="1" PublicKeyBlob="[public key goes here]" /> </CodeGroup> And that works great. However, we have several huge sharepoint farms, with many applications running on it. I'd like to avoid having to manually edit all policy files to include this xml snippet. Is there a way to automate this? For example, from a feature? With kind regards, Erwin van der Valk

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