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  • Multiple leaf methods problem in composite pattern

    - by Ondrej Slinták
    At work, we are developing an PHP application that would be later re-programmed into Java. With some basic knowledge of Java, we are trying to design everything to be easily re-written, without any headaches. Interesting problem came out when we tried to implement composite pattern with huge number of methods in leafs. What are we trying to achieve (not using interfaces, it's just an example): class Composite { ... } class LeafOne { public function Foo( ); public function Moo( ); } class LeafTwo { public function Bar( ); public function Baz( ); } $c = new Composite( Array( new LeafOne( ), new LeafTwo( ) ) ); // will call method Foo in all classes in composite that contain this method $c->Foo( ); It seems like pretty much classic Composite pattern, but problem is that we will have quite many leaf classes and each of them might have ~5 methods (of which few might be different than others). One of our solutions, which seems to be the best one so far and might actually work, is using __call magic method to call methods in leafs. Unfortunately, we don't know if there is an equivalent of it in Java. So the actual question is: Is there a better solution for this, using code that would be eventually easily re-coded into Java? Or do you recommend any other solution? Perhaps there's some different, better pattern I could use here. In case there's something unclear, just ask and I'll edit this post.

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  • Template trick to optimize out allocations

    - by anon
    I have: struct DoubleVec { std::vector<double> data; }; DoubleVec operator+(const DoubleVec& lhs, const DoubleVec& rhs) { DoubleVec ans(lhs.size()); for(int i = 0; i < lhs.size(); ++i) { ans[i] = lhs[i]] + rhs[i]; // assume lhs.size() == rhs.size() } return ans; } DoubleVec someFunc(DoubleVec a, DoubleVec b, DoubleVec c, DoubleVec d) { DoubleVec ans = a + b + c + d; } Now, in the above, the "a + b + c + d" will cause the creation of 3 temporary DoubleVec's -- is there a way to optimize this away with some type of template magic ... i.e. to optimize it down to something equivalent to: DoubleVec ans(a.size()); for(int i = 0; i < ans.size(); i++) ans[i] = a[i] + b[i] + c[i] + d[i]; You can assume all DoubleVec's have the same # of elements. The high level idea is to have do some type of templateied magic on "+", which "delays the computation" until the =, at which point it looks into itself, goes hmm ... I'm just adding thes numbers, and syntheizes a[i] + b[i] + c[i] + d[i] ... instead of all the temporaries. Thanks!

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  • Book/topic recommendations for a programmer returning to programming.

    - by Jason Tan
    I used to be a developer in Java, PHP, perl and C/C++ (the C++ bit badly - the others not too badly, I hope). This was back in the Java 1.3/1.4 days. We used raw JDBC, swing, servlets, JSP and ant (sometimes even make). Eclipse was new. Then I joined a deployment team and became a deployment engineer and then after the deployment engineer work became a full time sys admin.You get the idea - my experience is a generation or two old in programming terms - maybe older. I'm interested in getting back into Java and perhaps Ruby development, but feel I will be waaaaay behind the technological 8 ball. Can you folks suggest some books (or sites) that would be worth reading to catch up with the last 5-10 years of the development world. I.e. what should I read to try and catch up with where development is now? I see lots of stuff on the web, but what are people in the fabled "real world" using? (are lots of people being SOA based apps? Are they using XP methodology) The sorts of things I'm interested in finding out about/catching up on are: Methodologies Design patterns APIs/Frameworks/Technologies Other stuff you deem current/interesting/relevant. So if you have any thoughts or can recommend any books (especially new classics - you know the 's equivalent to K&R C or "The mythical man month"). Thanks for any thoughts you might share.

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  • Java string to double conversion.

    - by wretrOvian
    Hi, I've been reading up on the net about the issues with handling float and double types in java. Unfortunately, the image is still not clear. Hence, i'm asking here direct. :( My MySQL table has various DECIMAL(m,d) columns. The m may range from 5 to 30. d stays a constant at 2. Question 1. What equivalent data-type should i be using in Java to work (i.e store, retrieve, and process) with the size of the values in my table? (I've settled with double - hence this post). Question 2. While trying to parse a double from a string, i'm getting errors Double dpu = new Double(dpuField.getText()); for example - "1" -> java.lang.NumberFormatException: empty String "10" -> 1.0 "101" -> 10.0 "101." -> 101.0 "101.1" -> 101.0 "101.19" -> 101.1 What am i doing wrong? What is the correct way to convert a string to a double value? And what measures should i take to perform operations on such values?

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  • JNA Passing Structure By Reference Help

    - by tyeh26
    Hi all, I'm trying to use JNA to talk over a USB device plugged into the computer. Using Java and a .dll that was provided to me. I am having trouble with the Write function: C code: typedef struct { unsigned int id; unsigned int timestamp; unsigned char flags; unsigned char len; unsigned char data[16]; } CANMsg; CAN_STATUS canplus_Write( CANHANDLE handle, //long CANMsg *msg ); Java Equivalent: public class CANMsg extends Structure{ public int id = 0; public int timestamp = 0; public byte flags = 0; public byte len = 8; public byte data[] = new byte[16]; } int canplus_Write(NativeLong handle, CANMsg msg); I have confirmed that I can open and close the device. The close requires the NativeLong handle, so i am assuming that the CANMsg msg is the issue here. I have also confirmed that the device works when tested with C only code. I have read the the JNA documentation thoroughly... I think. Any pointers. Thanks all.

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  • OrderBy Linq.Expression as parameter = (Of Func(Of T,IComparable)) to perform LinqToEntity is not working

    - by NicoJuicy
    I'd like to get this working: Call: (Count & Page are used for pagination, so Count = 20 and Page = 1 for example, for the first 20 values). Sorting should be by name LeverancierService.GetLeveranciers(Function(el) el.Name, Count, Page) Equivalent in c#: LeverancierService.GetLeveranciers(el= el.Name, Count, Page) Method that gives an error (parameters shown above): Public Overridable Function GetAllPaged(orderby As Expression(Of Func(Of T, IComparable)), ByVal Count As Integer, ByVal Page As Integer) As IEnumerable(Of T) Return dbset.OrderBy(orderby).Skip((Page - 1) * Count).Take(Count).ToList() End Function Already tried changing it to this, but it gives the same error: Public Overridable Function GetAllPaged(Of TOrderBy)(orderby As Expression(Of Func(Of T, TOrderBy)), ByVal Count As Integer, ByVal Page As Integer) As IEnumerable(Of T) Return dbset.OrderBy(orderby).Skip((Page - 1) * Count).Take(Count).ToList() End Function Error: Unable to cast the type 'System.String' to type 'System.IComparable'. LINQ to Entities only supports casting Entity Data Model primitive types. Any idea how to do this? Extra info: I'm in a DDD-layered application, so the parameter should stay the same as the called method is an overridden interface (eg. if i change this, i have to do this for 200 times or so, because it's in VB.Net and not in C# (= 1 change) ) I know there is a way to change the expression to a string and then use DLinq (= Dynamic Linq), but that's not how it should be.

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  • Getting a gestureoverlayview

    - by Codejoy
    I have been using some nice tutorials on drawing graphics on my android. I wanted to also add in the cool gesture demo found here: http://developer.android.com/resources/articles/gestures.html That takes these lines of code: GestureOverlayView gestures = (GestureOverlayView) findViewById(R.id.gestures); gestures.addOnGesturePerformedListener(this); This is fine and dandy yet I realize in my demo i'm trying to build using code from "Playing with Graphics in Android". The demos make sense, everything makes sense but I found out by using: setContentView(new Panel(this)); as is required by the Playing With Graphics tutorials, then the findViewById seems to no longer be valid and returns null. At first I was about to post a stupider question as to why this is happening, a quick test of playing with the setContentView made me realize the cause of findViewById returning null, I just do not know how to remedy this issue. Whats the key I am missing here? I realize that the new Panel is doinking some reference up but I am not sure how to make the connection here. The: R.id.gestures is defined right int he main.xml as: (just like the tutorial) <android.gesture.GestureOverlayView android:id="@+id/gestures" android:layout_width="fill_parent" android:layout_height="0dip" android:layout_weight="1.0" /> So I did confirm the setContentView(new Panel(this)) is causing the issue. So I know the issue is that I have to figure out how to add the android.gesture.GestureOverlayView to the panel class somehow, I am just not sure how to go about this. After fighting with this I generally know what I need to do just now how to do it. I think I need either the equivalent of creating a panel in that main.xml OR figuring out how to build whats in main.xml for the gestures in code. I am close because I did this: GestureOverlayView gestures = new GestureOverlayView(this); which gets me a non null gestures now, unfortunately since I am not telling it to fill Parent anywhere I don't think its really showing up, so I am trying hard to figure out layout pa rams. Am I even on the right track?

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  • Need help extrapolating Java code

    - by Berlioz
    If anyone familiar with Rebecca Wirfs-Brock, she has a piece of Java code found in her book titled, Object Design: Roles, Responsibilities, and Collaborations. Here is the quote Applying Double Dispatch to a Specific Problem To implement the game Rock, Paper, Scissors we need to write code that determines whether one object “beats” another. The game has nine possible outcomes based on the three kinds of objects. The number of interactions is the cross product of the kinds of objects. Case or switch statements are often governed by the type of data that is being operated on. The object-oriented language equivalent is to base its actions on the class of some other object. In Java, it looks like this Here is the piece of Java code on page 16 ' import java.util.*; import java.lang.*; public class Rock { public static void main(String args[]) { } public static boolean beats(GameObject object) { if (object.getClass.getName().equals("Rock")) { result = false; } else if (object.getClass.getName().equals("Paper")) { result = false; } else if(object.getClass.getName().equals("Scissors")) { result = true; } return result; } }' ===This is not a very good solution. First, the receiver needs to know too much about the argument. Second, there is one of these nested conditional statements in each of the three classes. If new kinds of objects could be added to the game, each of the three classes would have to be modified. Can anyone share with me how to get this "less than optimal" piece of code to work in order to see it 'working'. She proceeds to demonstrate a better way, but I will spare you. Thanks

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  • Code Golf: Numeric Ranges

    - by SLaks
    Mods: Can you please make this Community Wiki? Challenge Compactify a long list of numbers by replacing consecutive runs with ranges. Example Input 1, 2, 3, 4, 7, 8, 10, 12, 13, 14, 15 Output: 1 - 4, 7, 8, 10, 12 - 15 Note that ranges of two numbers should be left as is. (7, 8; not 7 - 8) Rules You can accept a list of integers (or equivalent datatype) as a method parameter, from the commandline, or from standard in. (pick whichever option results in shorter code) You can output a list of strings by printing them, or by returning either a single string or set of strings. Reference Implementation (C#) IEnumerable<string> Sample(IList<int> input) { for (int i = 0; i < input.Count; ) { var start = input[i]; int size = 1; while (++i < input.Count && input[i] == start + size) size++; if (size == 1) yield return start.ToString(); else if (size == 2) { yield return start.ToString(); yield return (start + 1).ToString(); } else if (size > 2) yield return start + " - " + (start + size - 1); } }

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  • Better language or checking tool?

    - by rwallace
    This is primarily aimed at programmers who use unmanaged languages like C and C++ in preference to managed languages, forgoing some forms of error checking to obtain benefits like the ability to work in extremely resource constrained systems or the last increment of performance, though I would also be interested in answers from those who use managed languages. Which of the following would be of most value? A language that would optionally compile to CLR byte code or to machine code via C, and would provide things like optional array bounds checking, more support for memory management in environments where you can't use garbage collection, and faster compile times than typical C++ projects. (Think e.g. Ada or Eiffel with Python syntax.) A tool that would take existing C code and perform static analysis to look for things like potential null pointer dereferences and array overflows. (Think e.g. an open source equivalent to Coverity.) Something else I haven't thought of. Or put another way, when you're using C family languages, is the top of your wish list more expressiveness, better error checking or something else? The reason I'm asking is that I have a design and prototype parser for #1, and an outline design for #2, and I'm wondering which would be the better use of resources to work on after my current project is up and running; but I think the answers may be useful for other tools programmers also. (As usual with questions of this nature, if the answer you would give is already there, please upvote it.)

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  • Haskell function composition (.) and function application ($) idioms: correct use.

    - by Robert Massaioli
    I have been reading Real World Haskell and I am nearing the end but a matter of style has been niggling at me to do with the (.) and ($) operators. When you write a function that is a composition of other functions you write it like: f = g . h But when you apply something to the end of those functions I write it like this: k = a $ b $ c $ value But the book would write it like this: k = a . b . c $ value Now to me they look functionally equivalent, they do the exact same thing in my eyes. However, the more I look, the more I see people writing their functions in the manner that the book does: compose with (.) first and then only at the end use ($) to append a value to evaluate the lot (nobody does it with many dollar compositions). Is there a reason for using the books way that is much better than using all ($) symbols? Or is there some best practice here that I am not getting? Or is it superfluous and I shouldn't be worrying about it at all? Thanks.

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  • Avoiding duplication in setting properties on the task in Rake tasks

    - by Stray
    I have a bunch of rake building tasks. They each have unique input / output properties, but the majority of the properties I set on the tasks are the same each time. Currently I'm doing that via simple repetition like this: task :buildThisModule => "bin/modules/thisModule.swf" mxmlc "bin/modules/thisModule.swf" do |t| t.input = "src/project/modules/ThisModule.as" t.prop1 = value1 t.prop2 = value2 ... (And many more property=value sets that are the same in each task) end task :buildThatModule => "bin/modules/thatModule.swf" mxmlc "bin/modules/thatModule.swf" do |t| t.input = "src/project/modules/ThatModule.as" t.prop1 = value1 t.prop2 = value2 ... (And many more property=value sets that are the same in each task) end In my usual programming headspace I'd expect to be able to break out the population of the recurring task properties to a re-usable function. Is there a rake analogy for this? Some way I can have a single function where the shared properties are set on any task? Something equivalent to: task :buildThisModule => "bin/modules/thisModule.swf" mxmlc "bin/modules/thisModule.swf" do |t| addCommonTaskParameters(t) t.input = "src/project/modules/ThisModule.as" end task :buildThatModule => "bin/modules/thatModule.swf" mxmlc "bin/modules/thatModule.swf" do |t| addCommonTaskParameters(t) t.input = "src/project/modules/ThatModule.as" end Thanks.

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  • How can I test a form that requires the entry of two random characters from a security phrase?

    - by lawm
    I need to test a two-stage login system which first asks for your email address and password and then presents the user with two select lists containing [a-zA-Z0-9]. The labels beside the drop down's are of the form 'Select character X from your security phrase', where X is a random character index from a known security phrase. I'd rather not stub the code for an acceptance test, so is it possible to write a matcher in cucumber which will, given that we know the whole phrase, select the required character in each of the two lists? Here is the scenario I have so far and the steps involved: Scenario: valid login email, password and secret phrase takes me to the dashboard Given I am not logged in When I log in as "[email protected]" Then I should be on the dashboard page And I should see "Your Dashboard" When /^I log in as "([^\"]*)"$/ do |login| visit path_to('Login page') fill_in "Email", :with => login fill_in "Password", :with => "Password123" click_button "Log in" response.should contain("Please verify some characters from your security phrase") select "a", :from => "Select character X of your security phrase" select "b", :from => "Select character Y of your security phrase" click_button "Submit" end For example, if the security phrase is 'Secret123', X = 3 and Y = 8, the above would have to produce the equivalent of: select "c", :from => "Select character 3 of your security phrase" select "2", :from => "Select character 8 of your security phrase" The numbers X and Y in the actual page are inside span#svc_1 and span#svc_2 respectively. Thanks,

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  • Use cases of [ordered], the new PowerShell 3.0 feature

    - by Roman Kuzmin
    PowerShell 3.0 CTP1 introduces a new feature [ordered] which is somewhat a shortcut for OrderedDictionary. I cannot imagine practical use cases of it. Why is this feature really useful? Can somebody provide some useful examples? Example: this is, IMHO, rather demo case than practical: $a = [ordered]@{a=1;b=2;d=3;c=4} (I do not mind if it is still useful, then I am just looking for other useful cases). I am not looking for use cases of OrderedDictionary, it is useful, indeed. But we can use it directly in v2.0 (and I do a lot). I am trying to understand why is this new feature [ordered] needed in addition. Collected use cases from answers: $hash = [ordered]@{} is shorter than $hash = New-Object System.Collections.Specialized.OrderedDictionary N.B. ordered is not a real shortcut for the type. New-Object ordered does not work. N.B. 2: But this is still a good shortcut because (I think, cannot try) it creates typical for PowerShell case insensitive dictionary. The equivalent command in v2.0 is too long, indeed: New-Object System.Collections.Specialized.OrderedDictionary]([System.StringComparer]::OrdinalIgnoreCase)

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  • .NET framework execution aborted while executing CLR stored procedure?

    - by Sean Ochoa
    I constructed a stored procedure that does the equivalent of FOR XML AUTO in SQL Server 2008. Now that I'm testing it, it gives me a really unhelpful error message. What does this error mean? Msg 10329, Level 16, State 49, Procedure ForXML, Line 0 .NET Framework execution was aborted. System.Threading.ThreadAbortException: Thread was being aborted. System.Threading.ThreadAbortException: at System.Runtime.InteropServices.Marshal.PtrToStringUni(IntPtr ptr, Int32 len) at System.Data.SqlServer.Internal.CXVariantBase.WSTRToString() at System.Data.SqlServer.Internal.SqlWSTRLimitedBuffer.GetString(SmiEventSink sink) at System.Data.SqlServer.Internal.RowData.GetString(SmiEventSink sink, Int32 i) at Microsoft.SqlServer.Server.ValueUtilsSmi.GetValue(SmiEventSink_Default sink, ITypedGettersV3 getters, Int32 ordinal, SmiMetaData metaData, SmiContext context) at Microsoft.SqlServer.Server.ValueUtilsSmi.GetValue200(SmiEventSink_Default sink, SmiTypedGetterSetter getters, Int32 ordinal, SmiMetaData metaData, SmiContext context) at System.Data.SqlClient.SqlDataReaderSmi.GetValue(Int32 ordinal) at System.Data.SqlClient.SqlDataReaderSmi.GetValues(Object[] values) at System.Data.ProviderBase.DataReaderContainer.CommonLanguageSubsetDataReader.GetValues(Object[] values) at System.Data.ProviderBase.SchemaMapping.LoadDataRow() at System.Data.Common.DataAdapter.FillLoadDataRow(SchemaMapping mapping) at System.Data.Common.DataAdapter.FillFromReader(DataSet dataset, DataTable datatable, String srcTable, DataReaderContainer dataReader, Int32 startRecord, Int32 maxRecords, DataColumn parentChapterColumn, Object parentChapterValue) at System.Data.Common.DataAdapter.Fill(DataTable[] dataTables, IDataReader dataReader, Int32 startRecord, Int32 maxRecords) at System.Data.Common.DbDataAdapter.FillInternal(DataSet dataset, DataTable[] datatables, Int32 startRecord, Int32 maxRecords, String srcTable, IDbCommand command, CommandBehavior behavior) at System.Data.Common.DbDataAdapter.Fill(DataTable[] dataTables, Int32 startRecord, Int32 maxRecords, IDbCommand command, CommandBehavior behavior) at System.Data.Common.DbDataAdapter.Fill(DataTable dataTable) at ForXML.GetXML...

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  • How to get timestamp of tick precision in .NET / C#?

    - by Hermann
    Up until now I used DateTime.Now for getting timestamps, but I noticed that if you print DateTime.Now in a loop you will see that it increments in descrete jumps of approx. 15 ms. But for certain scenarios in my application I need to get the most accurate timestamp possible, preferably with tick (=100 ns) precision. Any ideas? Update: Apparently, StopWatch / QueryPerformanceCounter is the way to go, but it can only be used to measure time, so I was thinking about calling DateTime.Now when the application starts up and then just have StopWatch run and then just add the elapsed time from StopWatch to the initial value returned from DateTime.Now. At least that should give me accurate relative timestamps, right? What do you think about that (hack)? NOTE: StopWatch.ElapsedTicks is different from StopWatch.Elapsed.Ticks! I used the former assuming 1 tick = 100 ns, but in this case 1 tick = 1 / StopWatch.Frequency. So to get ticks equivalent to DateTime use StopWatch.Elapsed.Ticks. I just learned this the hard way. NOTE 2: Using the StopWatch approach, I noticed it gets out of sync with the real time. After about 10 hours, it was ahead by 5 seconds. So I guess one would have to resync it every X or so where X could be 1 hour, 30 min, 15 min, etc. I am not sure what the optimal timespan for resyncing would be since every resync will change the offset which can be up to 20 ms.

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  • SELECT set of most recent id, amount FROM table, where id occurs many times

    - by Jon Cram
    I have a table recording the amount of data transferred by a given service on a given date. One record is entered daily for a given service. I'd like to be able to retrieve the most recent amount for a set of services. Example data set: serviceId | amount | date ------------------------------- 1 | 8 | 2010-04-12 2 | 11 | 2010-04-12 2 | 14 | 2010-04-11 3 | 9 | 2010-04-11 1 | 6 | 2010-04-10 2 | 5 | 2010-04-10 3 | 22 | 2010-04-10 4 | 17 | 2010-04-19 Desired response (service ids 1,2,3): serviceId | amount | date ------------------------------- 1 | 8 | 2010-04-12 2 | 11 | 2010-04-12 3 | 9 | 2010-04-11 Desired response (service ids 2, 4): serviceId | amount | date ------------------------------- 2 | 11 | 2010-04-12 4 | 17 | 2010-04-19 This retrieves the equivalent as running the following once per serviceId: SELECT serviceId, amount, date FROM table WHERE serviceId = <given serviceId> ORDER BY date DESC LIMIT 0,1 I understand how I can retrieve the data I want in X queries. I'm interested to see how I can retrieve the same data using either a single query or at the very least less than X queries. I'm very interested to see what might be the most efficient approach. The table currently contains 28809 records. I appreciate that there are other questions that cover selecting the most recent set of records. I have examined three such questions but have been unable to apply the solutions to my problem.

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  • iOS 7: Best way to implement an textview that presents previous input but is easy to clear

    - by Frank R.
    I'm porting a Mac app to the iPhone and I've run into an unexpected problem. On the Mac there's a text field that is automatically pre-selected (= first responder) when a dialog shows up. The text field shows the text you entered in the field the last time and the text is pre-selected so that if you just start typing it gets cleared away. If you want to edit the existing text instead you just hit the forwards or backwards arrow. On the iPhone this behavior seems very hard to implement. The text view shows up with the old text and I can even get it to pre-select but whatever I do the result is not quite right. When I use [aTextView setMarkedText: myText selectedRange: newRange]; the text does show up as marked and if I just start typing the old text goes away. However there's no equivalent to the cursor keys on iOS, so I cannot NOT erase the text.. which is hardly the point. What kind of iOS idiom would be appropriate for giving the option to either edit or overwrite existing text? Best regards, Frank

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  • Tools for managing code deployment/versioning for IIS / Windows enviroments

    - by RizwanK
    I've got a strong background in Linux and OSX, and just left a job where I was architecting systems based on those platforms. Now I've got a Windows Server running IIS that has a number of different websites that it hosts. Most of them are just a bunch of HTML, JS and Images, with some ASP for some customer tools. (Each website has a different set of customer tools, or they are the same tools, but with minor code changes between them.) I'm also adding a develop web server with the same code, but the 'bleeding edge' stuff. I need an effective way of managing changes and updates to the overall codebase (henceforth referring to both the images and the html and the asp, for all the sites). When a dev (or webmaster) checks in changes, I want it to show up automatically on the developer server, but should be manually pushed out to the live server. I'd be tempted to just make the websites SVN repositories, but I'd be concerned about the overhead of having the webdeveloper having to log into the server and trigger an SVN update via commandline/tortise (and heaven forbid, manage tags). Ideally I'd also manage IIS profile settings between the systems, but the major need is to be able to manage the process, and expose it to our ASP developer, and our webmaster, both of which are used to just FTPing up the files to the live site. So, any recommendations on tools (beyond some SVN hacking with BAT files + teaching the webmaster how to log into the server and do updates) or workflows that would help this out? I even considered an RPM type package (or some Windows equivalent, of course) to manage the live server, but that seems like a bit too much overhead. Thanks.

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  • .Net Hash Codes no longer persistent?

    - by RobV
    I have an API where various types have custom hash codes. These hash codes are based on getting the hash of a string representation of the object in question. Various salting techniques are used so that as far as possible Hash Codes do not collide and that Objects of different types with equivalent string representations have different Hash Codes. Obviously since the Hash Codes are based on strings there are some collisions (infinite strings vs the limited range of 32 bit integers). I use hashes based on string representations since I need the hashes to persist over sessions and particularly for use in database storage of objects. Suddenly today my code has started generating different hash codes for Objects which is breaking all kinds of things. It was working earlier today and I haven't touched any of the code involved in Hash Code generation. I'm aware that the .Net documentation allows for implementation of hash codes between .Net framework versions to change (and between 32 and 64 bit versions) but I haven't changed the framework version and there has been no framework updates recently as far as I can remember Any ideas because this seems really weird? Edit Hash Codes are generated like follows: //Compute Hash Code this._hashcode = (this._nodetype + this.ToString() + PlainLiteralHashCodeSalt).GetHashCode();

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  • Retain numerical precision in an R data frame?

    - by David
    When I create a dataframe from numeric vectors, R seems to truncate the value below the precision that I require in my analysis: data.frame(x=0.99999996) returns 1 (see update 1) I am stuck when fitting spline(x,y) and two of the x values are set to 1 due to rounding while y changes. I could hack around this but I would prefer to use a standard solution if available. example Here is an example data set d <- data.frame(x = c(0.668732936336141, 0.95351462456867, 0.994620622127435, 0.999602102672081, 0.999987126195509, 0.999999955814133, 0.999999999999966), y = c(38.3026509783688, 11.5895099585560, 10.0443344234229, 9.86152339768516, 9.84461434575695, 9.81648333804257, 9.83306725758297)) The following solution works, but I would prefer something that is less subjective: plot(d$x, d$y, ylim=c(0,50)) lines(spline(d$x, d$y),col='grey') #bad fit lines(spline(d[-c(4:6),]$x, d[-c(4:6),]$y),col='red') #reasonable fit Update 1 Since posting this question, I realize that this will return 1 even though the data frame still contains the original value, e.g. > dput(data.frame(x=0.99999999996)) returns structure(list(x = 0.99999999996), .Names = "x", row.names = c(NA, -1L), class = "data.frame") Update 2 After using dput to post this example data set, and some pointers from Dirk, I can see that the problem is not in the truncation of the x values but the limits of the numerical errors in the model that I have used to calculate y. This justifies dropping a few of the equivalent data points (as in the example red line).

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  • Is it possible to achieve MAX(As,Ad) openGL blending?

    - by Jeff B
    I am working on a game where I want to create shadows under a series of sprites on a grid. The shadows are larger than the sprites themselves and the sprites are animated (i.e. move and rotate). I cannot simply render them into the sprite png, or the shadows will overlap adjacent sprites. I also cannot simply put shadows on a lower layer by themselves, because when they overlap, they will create dark bands at their intersection. These sprites are animated, so it is not feasible to render these en masse. Basically, I want the sprites' shadows to blend together such that they max out at a set opacity. Example: I believe this is equivalent to an openGL blending of (Rs,Gs,Bs,Max(As,Ds)), where I don't really care about R,G, and B, as it will always be the same color in src and dst. However, this is not a valid openGL blending mode. Is there an easy way to accomplish this, especially in cocos2d-iphone? I would be able to approximate this by making the shadow sprites opaque, then applying them both to a parent sprite, and making the parent sprite 40% opacity. However, the way cocos2d works, this only sets the opacity of each child to 40%, rather than the combined sprite image, which results in the same stripe.

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  • How to control the "flow" of an ASP.NET MVC (3.0) web app that relies on Facebook membership, with Facebook C# SDK?

    - by Chad
    I want to totally remove the standard ASP.NET membership system and use Facebook only for my web app's membership. Note, this is not a Facebook canvas app question. Typically, in an ASP.NET app you have some key properties & methods to control the "flow" of an app. Notably: Request.IsAuthenticated, [Authorize] (in MVC apps), Membership.GetUser() and Roles.IsUserInRole(), among others. It looks like [FacebookAuthorize] is equivalent to [Authorize]. Also, there's some standard work I do across all controllers in my site. So I built a BaseController that overrides OnActionExecuting(FilterContext). Typically, I populate ViewData with the user's profile within this action. Would performance suffer if I made a call to fbApp.Get("me") in this action? I use the Facebook Javascript SDK to do registration, which is nice and easy. But that's all client-side, and I'm having a hard time wrapping my mind around when to use client-side facebook calls versus server-side. There will be a point when I need to grab the user's facebook uid and store it in a "profile" table along with a few other bits of data. That would probably be best handled on the return url from the registration plugin... correct? On a side note, what data is returned from fbApp.Get("me")?

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  • Rapid Opening and Closing System.IO.StreamWriter in C#

    - by ccomet
    Suppose you have a file that you are programmatically logging information into with regards to a process. Kinda like your typical debug Console.WriteLine, but due to the nature of the code you're testing, you don't have a console to write onto so you have to write it somewhere like a file. My current program uses System.IO.StreamWriter for this task. My question is about the approach to using the StreamWriter. Is it better to open just one StreamWriter instance, do all of the writes, and close it when the entire process is done? Or is it a better idea to open a new StreamWriter instance to write a line into the file, then immediately close it, and do this for every time something needs to be written in? In the latter approach, this would probably be facilitated by a method that would do just that for a given message, rather than bloating the main process code with excessive amounts of lines. But having a method to aid in that implementation doesn't necessarily make it the better choice. Are there significant advantages to picking one approach or the other? Or are they functionally equivalent, leaving the choice on the shoulders of the programmer?

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  • Ruby 1.9: turn these 4 arrays into hash of key/value pairs

    - by randombits
    I have four arrays that are coming in from the client. Let's say that there is an array of names, birth dates, favorite color and location. The idea is I want a hash later where each name will have a hash with respective attributes: Example date coming from the client: [name0, name1, name2, name3] [loc0, loc1] [favcololor0, favcolor1] [bd0, bd1, bd2, bd3, bd4, bd5] Output I'd like to achieve: name0 => { location => loc0, favcolor => favcolor0, bd => bd0 } name1 => { location => loc1, favcolor => favcolor1, bd => bd1 } name2 => { location => nil, favcolor => nil, bd => bd2 } name3 => { location => nil, favcolor => nil, bd => bd3 } I want to have an array at the end of the day where I can iterate and work on each particular person hash. There need not be an equivalent number of values in each array. Meaning, names are required.. and I might receive 5 of them, but I only might receive 3 birth dates, 2 favorite colors and 1 location. Every missing value will result in a nil. How does one make that kind of data structure with Ruby 1.9?

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