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  • Ruby on Rails unknown attribute form error

    - by Ulkmun
    I'm attempting to create a form which will allow me to upload a file.. I've got the following form.. <div class="field"> <%= f.label :title %><br /> <%= f.text_field :title %> </div> <div class="field"> <%= f.label :body %><br /> <%= f.text_area :body, "cols" => 100, "rows" => 40 %> </div> <div class="field"> <%= f.label :upload %><br /> <%= f.file_field :upload %> </div> <div class="actions"> <%= f.submit %> </div> I've got a controller which seems to error in this function.. # POST /posts # POST /posts.xml def create @post = Post.new(params[:post]) @post = DataFile.save(params[:upload]) ##render :text => "File has been uploaded successfully" respond_to do |format| if @post.save format.html { redirect_to(@post, :notice => 'Post was successfully created.') } format.xml { render :xml => @post, :status => :created, :location => @post } else format.html { render :action => "new" } format.xml { render :xml => @post.errors, :status => :unprocessable_entity } end end end That's the method that get's called when I create the post. The error is unknown attribute: upload app/controllers/posts_controller.rb:42:in ``new' app/controllers/posts_controller.rb:42:in ``create'

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  • Friends, templates, overloading <<

    - by Crystal
    I'm trying to use friend functions to overload << and templates to get familiar with templates. I do not know what these compile errors are: Point.cpp:11: error: shadows template parm 'class T' Point.cpp:12: error: declaration of 'const Point<T>& T' for this file #include "Point.h" template <class T> Point<T>::Point() : xCoordinate(0), yCoordinate(0) {} template <class T> Point<T>::Point(T xCoordinate, T yCoordinate) : xCoordinate(xCoordinate), yCoordinate(yCoordinate) {} template <class T> std::ostream &operator<<(std::ostream &out, const Point<T> &T) { std::cout << "(" << T.xCoordinate << ", " << T.yCoordinate << ")"; return out; } My header looks like: #ifndef POINT_H #define POINT_H #include <iostream> template <class T> class Point { public: Point(); Point(T xCoordinate, T yCoordinate); friend std::ostream &operator<<(std::ostream &out, const Point<T> &T); private: T xCoordinate; T yCoordinate; }; #endif My header also gives the warning: Point.h:12: warning: friend declaration 'std::ostream& operator<<(std::ostream&, const Point<T>&)' declares a non-template function Which I was also unsure why. Any thoughts? Thanks.

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  • Basic SWIG C++ use for Java

    - by duckworthd
    I've programmed a couple years in both C++ and Java, but I've finally come to a point where I need to bring a little unification between the two -- ideally, using SWIG. I've written a tiny and fairly pointless little class called Example: #include <stdio.h> class Example { public: Example(); ~Example(); int test(); }; #include "example.h" Example::Example() { printf("Example constructor called\n"); } Example::~Example() { printf("Example destructor called\n"); } int Example::test() { printf("Holy sh*t, I work!\n"); return 42; } And a corresponding interface file: /* File: example.i */ %module test %{ #include "example.h" %} %include "example.h" Now I have questions. Firstly, when I want to actually run SWIG initially, am I supposed to use the example_wrap.c (from swig -java example.i) or example_wrap.cxx (from swig -c++ example.i) file when recompiling with my original example.cpp? Or perhaps both? I tried both and the latter seemed most likely, but when I recompile as so: g++ example.cpp example_wrap.cxx -I/usr/lib/jvm/java-6-sun-.../include/ I get a host of errors regarding TcL of all things, asking me for the tcl.h header. I can't even wrap my mind around why it wants that much less needs it, and as such have found myself where I don't even know how to begin using SWIG.

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  • joomla! migration

    - by tim
    I have a Joomla! installation on a remote site and I want to run it locally. I'm running Joomla! locally on a Mac through a standard MAMP installation: Joomla 1.5.12 PHP 5.2.6 MySQL 5.0.41 Apache 2.0.59 OS X 10.5.8 I've added a configuration file to the local Joomla! directory with all the correct local settings, database name, database user-name, database password etc. etc. I've tried a lot of different settings. I've also recreated the remote database locally, ensuring everything copied correctly. I followed a few different sets of instructions with roughly the same steps on how to do the migration. All of the above has not worked for me; at best I get bits of text from the site rendered in the browser. Other times I get SQL errors. What I want is for an already set up remote Joomla! installation to run on my own local machine. Does anyone have any advice as to how to get this working, it'd be very much appreciated? Thanks.

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  • Batch processing JDBC

    - by Wai Hein
    I am practicing JDBC batch processing and having errors: error 1: Unsupported feature error 2: Execute cannot be empty or null Property files include: itemsdao.updateBookName = Update Books set bookname = ? where books.id = ? itemsdao.updateAuthorName = Update books set authorname = ? where books.id = ? I know I can execute about DML statements in one update, but I am practicing batch processing in JDBC. Below is my method public void update(Item item) { String query = null; try { connection = DbConnector.getConnection(); property = SqlPropertiesLoader.getProperties("dml.properties"); connection.setAutoCommit(false); if ( property == null ) { Logging.log.debug("dml.properties does not exist. Check property loader or file name is spelled right"); return; } query = property.getProperty("itemsdao.updateBookName"); statement = connection.prepareStatement(query); statement.setString(1, item.getBookName()); statement.setInt(2, item.getId()); statement.addBatch(query); query = property.getProperty("itemsdao.updateAuthorName"); statement = connection.prepareStatement(query); statement.setString(1, item.getAuthorName()); statement.setInt(2, item.getId()); statement.addBatch(query); statement.executeBatch(); connection.commit(); }catch (ClassNotFoundException e) { Logging.log.error("Connection class does not exist", e); } catch (SQLException e) { Logging.log.error("Violating PK constraint",e); } //helper class th finally { DbUtil.close(connection); DbUtil.closePreparedStatement(statement); }

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  • Help with interesting VS2010 and SQL2008 bug

    - by user355770
    Hey So im using Visual Studio 2010 to create a webpage. im calling some tabels from sql server 2008 here is where im confused... The code runs fine no errors. The pages works except im missing my rows in my 3rd column from the table. Everything else shows up. Ive checked to make sure the names are matching everywhere and that in sql the joins and such worked. Its just very weird that i'd be missing my 2 rows from the 3rd column. anyone have any ideas to help?? the error is in the tab called research material else if (tabTagId == "tpArlington_ProjectInformation") { repArlington_ProjectInformation.DataSource = ds; repArlington_ProjectInformation.DataBind(); } else if (tabTagId == "tpArlington_Plan") { repArlington_Plan.DataSource = ds; repArlington_Plan.DataBind(); } else if (tabTagId == "tpArlington_ResearchMaterial") { repArlington_ResearchMaterial.DataSource = ds; repArlington_ResearchMaterial.DataBind(); } else if (Session["projectAbbreviation"].ToString() == "ARLING") { tpArlington_ProjectInformation.HeaderText = "Project Information"; tpArlington_ProjectInformation.Visible = true; tpArlington_Plan.HeaderText = "Plan"; tpArlington_Plan.Visible = true; tpArlington_ResearchMaterial.HeaderText = "ResearchMaterial"; tpArlington_ResearchMaterial.Visible = true; getTabData("tpArlington_ProjectInformation"); getTabData("tpArlington_Plan"); getTabData("tpArlington_ReasearchMaterial"); } the 2 other tabs work perfect. the research material is where the problem is. the stuff in the tab doesn't come up. the text in the tab DOES come up but not the stuff from sql. the stuff in sql looks good, the ids match and everything is joined properly otherwise the other 2 tabs wouldnt work. that is what is confusing me. any suggestions or specific info you need just ask. thanks!

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  • The linking is not done (gcc compilation)

    - by Moons
    Hello everyone! So i have this issue : i am declaring some extern global variables in my C program. If I don't use the -c option for gcc, i get undefined references errors. But with that -c option, the linking is not done, which means that i don't have an executable generated. So how do I solve this? Here is my makefile. As I am not good with writing makefiles, I took one from another project then I changed a few things. So maybe I'm missing something here. # Makefile calculPi INCL = -I$(INCL_DIR) DEFS = -D_DEBUG_ CXX_FLAGS =-g -c -lpthread -lm CXX = gcc $(CXX_FLAGS) $(INCL) $(DEFS) LINK_CXX = gcc OBJ = approx.o producteur.o sequentialApproximation.o main.o LINKOBJ = approx.o producteur.o sequentialApproximation.o main.o BIN = calculPi.exe RM = rm -fv all: calculPi.exe clean: ${RM} *\~ \#*\# $(OBJ) clean_all: clean ${RM} $(BIN) cleanall: clean ${RM} $(BIN) $(BIN): $(OBJ) $(CXX) $(LINKOBJ) -o "calculPi.exe" main.o: main.c $(CXX) main.c -o main.o $(CXX_FLAGS) approx.o: approx.c approx.h $(CXX) -c approx.c -o approx.o $(CXX_FLAGS); producteur.o: producteur.c producteur.h $(CXX) -c producteur.c -o producteur.o $(CXX_FLAGS); sequentialApproximation.o : sequentialApproximation.c sequentialApproximation.h $(CXX) -c sequentialApproximation.c -o sequentialApproximation.o $(CXX_FLAGS);

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  • Adding custom UITableViewCell crashes the simulator.

    - by nevva
    Im trying to build my application using a custom UITableViewCell. This is the code in my UIViewController that adds the viewCell to the table: - (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath { NSLog(@"------- Tableview --------"); static NSString *MyIdentifier = @"MyIdentifier"; MyIdentifier = @"aCellIdentifier"; MyTableCell *cell = (MyTableCell *)[tableView dequeueReusableCellWithIdentifier:MyIdentifier]; if(cell == nil) { NSArray *[[NSBundle mainBundle] loadNibNamed:@"tblCellView" owner:self options:nil]; cell = tblCell; } [cell setLabelText:[NSString stringWithFormat:@"indexpath.row: %d", indexPath.row]]; //cell = [[[UITableViewCell alloc] initWithStyle:UITableViewCellStyleSubtitle reuseIdentifier:MyIdentifier] autorelease]; return cell; } if i uncomment the line above "return cell" it returns a regular UITableViewCell without any errors, but as soon as i try to implement my custom cell it crashes with this error: ------- Tableview -------- 2010-04-23 11:17:33.163 SogetGolf[26935:40b] * Assertion failure in -[UITableView _createPreparedCellForGlobalRow:withIndexPath:], /SourceCache/UIKit_Sim/UIKit-984.38/UITableView.m:4709 2010-04-23 11:17:33.164 SogetGolf[26935:40b] * Terminating app due to uncaught exception 'NSInternalInconsistencyException', reason: 'UITableView dataSource must return a cell from tableView:cellForRowAtIndexPath:' 2010-04-23 11:17:33.165 SogetGolf[26935:40b] Stack: ( ... I have configured the .xib file as one should with the proper outlets. And the identifier of the UITableViewCell corresponds with name im trying to load from NSBundle

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  • Mysterious double execution of Click handler after change to Windows 2008 Server

    - by mjn
    After moving a Delphi 2009 application from a Windows 2003 / Citrix environment to a 64 bit Windows 2008 R2 environment (users now use RDP instead of Citrix), there are frequent runtime errors which are caused by a double exection of a menu item click handler. The first call of the event handler opens a modal form. Then the same event handler is triggered again and thus a runtime exception occurs since the visible form can not be made modal. The madExcept stack trace looks like this: main thread ($2dc): 004ffa88 +06c Ladelist.exe Forms TCustomForm.ShowModal 0052f4ff +0bb Ladelist.exe DB TDataSet.SetActive 008fc9a1 +089 Ladelist.exe u_ladeli 928 +16 TForm1.EditLoadingList 008fadec +070 Ladelist.exe u_ladeli 504 +5 TForm1.OpenLoadingListClick <----- 2 004d6e27 +0a7 Ladelist.exe Menus TMenuItem.Click 004d857f +0ef Ladelist.exe Menus DoClick 004d866b +087 Ladelist.exe Menus TMenu.IsShortCut 005001c1 +04d Ladelist.exe Forms TCustomForm.IsShortCut 004e8dc0 +068 Ladelist.exe Controls TWinControl.IsMenuKey 004e8f89 +011 Ladelist.exe Controls TWinControl.CNSysKeyDown 004e247e +2d2 Ladelist.exe Controls TControl.WndProc 004e6983 +513 Ladelist.exe Controls TWinControl.WndProc 004fb5e8 +594 Ladelist.exe Forms TCustomForm.WndProc 004e20a4 +024 Ladelist.exe Controls TControl.Perform 004856e0 +014 Ladelist.exe Classes StdWndProc 004e609c +02c Ladelist.exe Controls TWinControl.MainWndProc 004856e0 +014 Ladelist.exe Classes StdWndProc 775b00e3 +02b ntdll.dll KiUserCallbackDispatcher 008fc9a1 +089 Ladelist.exe u_ladeli 928 +16 TForm1.EditLoadingList 008fadec +070 Ladelist.exe u_ladeli 504 +5 TForm1.OpenLoadingListClick <----- 1 004d6e27 +0a7 Ladelist.exe Menus TMenuItem.Click 004d857f +0ef Ladelist.exe Menus DoClick 004d866b +087 Ladelist.exe Menus TMenu.IsShortCut 005001c1 +04d Ladelist.exe Forms TCustomForm.IsShortCut 004e8dc0 +068 Ladelist.exe Controls TWinControl.IsMenuKey 004e8e0d +01d Ladelist.exe Controls TWinControl.CNKeyDown 004e247e +2d2 Ladelist.exe Controls TControl.WndProc 004e6983 +513 Ladelist.exe Controls TWinControl.WndProc 004fb5e8 +594 Ladelist.exe Forms TCustomForm.WndProc 004e20a4 +024 Ladelist.exe Controls TControl.Perform 004e609c +02c Ladelist.exe Controls TWinControl.MainWndProc 004856e0 +014 Ladelist.exe Classes StdWndProc 775b00e3 +02b ntdll.dll KiUserCallbackDispatcher 753c3675 +010 kernel32.dll BaseThreadInitThunk

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  • Jquery Resize Line of text To Fit Div Width

    - by Douglas Cottrell
    I am using the following script to resize a one line string to fit properly in a div box. <script type="text/javascript"> $( '.test' ).css( 'font-size', 0 ).each(function ( i, box2 ) { var width = $( box2 ).width(), line = $( box2 ).wrapInner( '<span style="white-space:nowrap">' ).children()[ 0 ]; function changeFontSize( n ) { $( box2 ).css( 'font-size', function ( i, val ) { return parseInt( val, 10 ) + n; }); } while ( $( line ).width() < width ) { changeFontSize( 1 ); } changeFontSize( -1 ); $( box2 ).text( $( line ).text() ); }); </script> This script works perfect in FF, Chrome, and opera. However in IE if the user is in compatability mode it errors and locks up the browser. I do not know enough about the older browsers to know what I have added that is not compatible. Any help is greatly appreciated.

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  • Caching queries in Django

    - by dolma33
    In a django project I only need to cache a few queries, using, because of server limitations, a cache table instead of memcached. One of those queries looks like this: Let's say I have a Parent object, which has a lot of Child objects. I need to store the result of the simple query parent.childs.all(). I have no problem with that, and everything works as expected with some code like key = "%s_children" %(parent.name) value = cache.get(key) if value is None: cache.set(key, parent.children.all(), CACHE_TIMEOUT) value = cache.get(key) But sometimes, just sometimes, the cache.set does nothing, and, after executing cache.set, cache.get(key) keeps returning None. After some test, I've noticed that cache.set is not working when parent.children.all().count() has higher values. That means that if I'm storing inside of key (for example) 600 children objects, it works fine, but it wont work with 1200 children. So my question is: is there a limit to the data that a key could store? How can I override it? Second question: which way is "better", the above code, or the following one? key = "%s_children" %(parent.name) value = cache.get(key) if value is None: value = parent.children.all() cache.set(key, value, CACHE_TIMEOUT) The second version won't cause errors if cache.set doesn't work, so it could be a workaround to my issue, but obviously not a solution. In general, let's forget about my issue, which version would you consider "better"?

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  • Fill listview from fragment

    - by Bohsen
    I have a layout file containing a listview that I would like to fill with the help of a Fragment. But it continues to give me errors. The layout file: <?xml version="1.0" encoding="utf-8"?> <RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android" android:layout_width="fill_parent" android:layout_height="fill_parent" > <ListView android:id="@+id/list" android:layout_width="fill_parent" android:layout_height="wrap_content" android:layout_alignParentTop="true" > </ListView> <TableLayout android:id="@+id/details" android:layout_width="fill_parent" android:layout_height="wrap_content" android:layout_alignParentBottom="true" android:stretchColumns="1" > <Button android:id="@+id/create_patient_button" android:layout_width="fill_parent" android:layout_height="wrap_content" android:text="@string/create_patient_button" /> </TableLayout> </RelativeLayout> My fragmentActivity: public class BasicFragmentActivity extends FragmentActivity { @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.create_patient_view); FragmentManager fm = getSupportFragmentManager(); Fragment fragment = fm.findFragmentById(R.id.list); if (fragment == null) { FragmentTransaction ft = fm.beginTransaction(); ft.add(R.id.list, new BasicFragment()); ft.commit(); // Make sure you call commit or your Fragment will not be added. // This is very common mistake when working with Fragments! } } } My ListFragment: public class BasicFragment extends ListFragment { private PatientAdapter pAdapter; @Override public void onActivityCreated(Bundle savedState) { super.onActivityCreated(savedState); pAdapter = new PatientAdapter(getActivity(), GFRApplication.dPatients); setListAdapter(pAdapter); } } The error: java.lang.UnsupportedOperationException: addView(View) is not supported in AdapterView

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  • Running Sitecore Production Site under a Virtual Directory

    - by danswain
    We are using Sitecore 6 on a Windows Server 2003 (32bit) dev machine. I know it's not recommended for the CMS editing site, but we've been told it is possible to get the front-end Sitecore websites to run from within a virtual directory. Here's the issue: we'd like to achieve what the below poor mans diagram shows. We have a website (.net 1.1) /WebSiteRoot (.net 1.1) | | |---- Custom .net 1.1 Web Application | |---- SiteCore frontend WebApplication (.net 2.0) | |---- Custom .net 2.0 WebApplication The Sitecore webApplication would contain the Sitecore pipeline in its web.config and we'd make use of the section to configure the virtual folder to allow for where our Sitecore app sits and point it to the appropriate place in the Content Tree. Is it possible to pull this off? This is just the customer facing website, there will be no CMS editing functionality on these servers, that will be done from a more standard Sitecore install inside the firewall on a different server. The errors we're encountering are centered around loading the the various config files in the App_Config folder. It seems to do a Server.MapPath on "/" initially (which is wrong for us) so we've tried putting absolute paths in the web.config and still no joy (I think there must be some hardcoded piece that looks for the Include directory). Any help would be greatly appreciated. Thanks

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  • How to amend return value design in OO manner?

    - by FrontierPsycho
    Hello. I am no newb on OO programming, but I am faced with a puzzling situation. I have been given a program to work on and extend, but the previous developers didn't seem that comfortable with OO, it seems they either had a C background or an unclear understanding of OO. Now, I don't suggest I am a better developer, I just think that I can spot some common OO errors. The difficult task is how to amend them. In my case, I see a lot of this: if (ret == 1) { out.print("yadda yadda"); } else if (ret == 2) { out.print("yadda yadda"); } else if (ret == 3) { out.print("yadda yadda"); } else if (ret == 0) { out.print("yadda yadda"); } else if (ret == 5) { out.print("yadda yadda"); } else if (ret == 6) { out.print("yadda yadda"); } else if (ret == 7) { out.print("yadda yadda"); } ret is a value returned by a function, in which all Exceptions are swallowed, and in the catch blocks, the above values are returned explicitly. Oftentimes, the Exceptions are simply swallowed, with empty catch blocks. It's obvious that swalllowing exceptions is wrong OO design. My question concerns the use of return values. I believe that too is wrong, however I think that using Exceptions for control flow is equally wrong, and I can't think of anything to replace the above in a correct, OO manner. Your input, please?

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  • How can I make VS2010 insert using statements in the order dictated by StyleCop rules.

    - by Hamish Grubijan
    The related default StyleCop rules are: Place using statements inside namespace. Sort using statements alphabetically. But ... System using come first (still trying to figure out if that means just using System; or using System[.*];). So, my use case: I find a bug and decide that I need to at least add an intelligible Assert to make debugging less painful for the next guy. So I start typing Debug.Assert( and intellisense marks it in Red. I hover mouse over Debug and between using System.Diagnostics; and System.Diagnostics.Debug I choose the former. This inserts using System.Diagnostics; after all other using statements. It would be nice if VS2010 did not assist me in writing code that won't build due to warnings as errors. How can I make VS2010 smarter? Is there some sort of setting, or does this require a full-fledged add-in of some sort?

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  • unresolved token/symbol in MC++ wrapper class calling native code

    - by rediVider
    I'm new to MC++ and have basically no idea what's going on yet. In trying to get this working i've determined many things that don't work, i'm just looking for one of the ways that will work. I have a mc++ class as follows that seems to have to be a "ref" class to allow me to see any methods/properties. public ref class EmCeePlusPlus { static void Open(void) { Testor* t = new Testor(); Testor::Open(); }; }; extern public class Testor { public: Testor() { }; static void Open(void) { int x = 3; int xx = cli_lock(x); }; }; Now, the only reason i created the class Testor, and moved the call to cli_open to it, is because i was getting a unresolved external symbol if i put the same call in the ref class. In this current code, however, I get an uresolved token error and unresolved symbol error ONLY if i have the call to Testor::Open(). If that line is commented then it compiles fine. As it is I get the errors below. cli_lock() is native code that is able to be called externally by other native DLLs with not problems. Any ideas where i should be looking? error LNK2028: unresolved token (0A000056) "extern "C" int __cdecl cli_lock(int)" (?cli_lock@@$$J0YAHH@Z) referenced in function "public: static void __cdecl Giga::Testor::Open(void)" (?Open@Testor@Giga@@$$FSAXXZ) error LNK2019: unresolved external symbol "extern "C" int __cdecl cli_lock(int)" (?cli_lock@@$$J0YAHH@Z) referenced in function "public: static void __cdecl Giga::Testor::Open(void)" (?Open@Testor@Giga@@$$FSAXXZ)

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  • How do I execute queries upon DB connection in Rails?

    - by sycobuny
    I have certain initializing functions that I use to set up audit logging on the DB server side (ie, not rails) in PostgreSQL. At least one has to be issued (setting the current user) before inserting data into or updating any of the audited tables, or else the whole query will fail spectacularly. I can easily call these every time before running any save operation in the code, but DRY makes me think I should have the code repeated in as few places as possible, particularly since this diverges greatly from the ideal of database agnosticism. Currently I'm attempting to override ActiveRecord::Base.establish_connection in an initializer to set it up so that the queries are run as soon as I connect automatically, but it doesn't behave as I expect it to. Here is the code in the initializer: class ActiveRecord::Base # extend the class methods, not the instance methods class << self alias :old_establish_connection :establish_connection # hide the default def establish_connection(*args) ret = old_establish_connection(*args) # call the default # set up necessary session variables for audit logging # call these after calling default, to make sure conn is established 1st db = self.class.connection db.execute("SELECT SV.set('current_user', 'test@localhost')") db.execute("SELECT SV.set('audit_notes', NULL)") # end "empty variable" err ret # return the default's original value end end end puts "Loaded custom establish_connection into ActiveRecord::Base" sycobuny:~/rails$ ruby script/server = Booting WEBrick = Rails 2.3.5 application starting on http://0.0.0.0:3000 Loaded custom establish_connection into ActiveRecord::Base This doesn't give me any errors, and unfortunately I can't check what the method looks like internally (I was using ActiveRecord::Base.method(:establish_connection), but apparently that creates a new Method object each time it's called, which is seemingly worthless cause I can't check object_id for any worthwhile information and I also can't reverse the compilation). However, the code never seems to get called, because any attempt to run a save or an update on a database object fails as I predicted earlier. If this isn't a proper way to execute code immediately on connection to the database, then what is?

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  • Why do I have to specify pure virtual functions in the declaration of a derived class in Visual C++?

    - by neuviemeporte
    Given the base class A and the derived class B: class A { public: virtual void f() = 0; }; class B : public A { public: void g(); }; void B::g() { cout << "Yay!"; } void B::f() { cout << "Argh!"; } I get errors saying that f() is not declared in B while trying do define void B::f(). Do I have to declare f() explicitly in B? I think that if the interface changes I shouldn't have to correct the declarations in every single class deriving from it. Is there no way for B to get all the virtual functions' declarations from A automatically? EDIT: I found an article that says the inheritance of pure virtual functions is dependent on the compiler: http://www.objectmentor.com/resources/articles/abcpvf.pdf I'm using VC++2008, wonder if there's an option for this.

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  • How to differentiate between exceptions i can show the user, and ones i can't?

    - by Ian Boyd
    i have some business logic that traps some logically invalid situations, e.g. trying to reverse a transaction that was already reversed. In this case the correct action is to inform the user: Transaction already reversed or Cannot reverse a reversing transaction or You do not have permission to reverse transactions or This transaction is on a session that has already been closed or This transaction is too old to be reversed The question is, how do i communicate these exceptional cases back to the calling code, so they can show the user? Do i create a separate exception for each case: catch (ETransactionAlreadyReversedException) MessageBox.Show('Transaction already reversed') catch (EReversingAReversingTransactionException) MessageBox.Show('Cannot reverse a reversing transaction') catch (ENoPermissionToReverseTranasctionException) MessageBox.Show('You do not have permission to reverse transactions') catch (ECannotReverseTransactionOnAlredyClosedSessionException) MessageBox.Show('This transaction is on a session that has already been closed') catch (ECannotReverseTooOldTransactionException) MessageBox.Show('This transaction is too old to be reversed') Downside for this is that when there's a new logical case to show the user: Tranasctions created by NSL cannot be reversed i don't simply show the user a message, and instead it leaks out as an unhandled excpetion, when really it should be handled with another MessageBox. The alternative is to create a single exception class: `EReverseTransactionException` With the understanding that any exception of this type is a logical check, that should be handled with a message box: catch (EReverseTransactionException) But it's still understood that any other exceptions, ones that involve, for example, an memory ECC parity error, continue unhandled. In other words, i don't convert all errors that can be thrown by the ReverseTransaction() method into EReverseTransactionException, only ones that are logically invalid cause of the user.

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  • Using a variable in a mysql query, in a C++ MFC program.

    - by D.Gaughan
    Hi, after extensive trawling of the internet I still havent found any solution for this problem. I`m writing a small C++ app that connects to an online database and outputs the data in a listbox. I need to enable a search function using an edit box, but I cant get the query to work while using a variable. My code is: res = mysql_perform_query (conn, "select distinct artist from Artists"); //res = mysql_perform_query (conn, "select album from Artists where artist = ' ' "); while((row = mysql_fetch_row(res)) != NULL){ CString str; UpdateData(); str = ("%s\n", row[0]); UpdateData(FALSE); m_list_control.AddString(str); } the first "res = " line is working fine, but I need the second one to work. I have a member variable m_search_edit set up for the edit box, but any way I try to include it in the sql statement causes errors. eg. res = mysql_perform_query (conn, "select album from Artists where artist = '"+m_search_edit+" ' "); causes this error: error C2664: 'mysql_perform_query' : cannot convert parameter 2 from 'class CString' to 'char *' No user-defined-conversion operator available that can perform this conversion, or the operator cannot be called" And when I convert m_search_edit to a char* it gives me a " Cannot add 2 pointers" error. Any way around this???

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  • Java: over-typed structures?

    - by HH
    Term over-type structure = a data structure that accepts different types, can be primitive or user-defined. I think ruby supports many types in structures such as tables. I tried a table with types 'String', 'char' and 'File' in Java but errs. How can I have over-typed structure in Java? How to show types in declaration? What about in initilization? Suppose a structure: INDEX VAR FILETYPE //0 -> file FILE //1 -> lineMap SizeSequence //2 -> type char //3 -> binary boolean //4 -> name String //5 -> path String Code import java.io.*; import java.util.*; public class Object { public static void print(char a) { System.out.println(a); } public static void print(String s) { System.out.println(s); } public static void main(String[] args) { Object[] d = new Object[6]; d[0] = new File("."); d[2] = 'T'; d[4] = "."; print(d[2]); print(d[4]); } } Errors Object.java:18: incompatible types found : java.io.File required: Object d[0] = new File("."); ^ Object.java:19: incompatible types found : char required: Object d[2] = 'T'; ^

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  • trouble with state monad composition

    - by user1308560
    I was trying out the example given at http://www.haskell.org/haskellwiki/State_Monad#Complete_and_Concrete_Example_1 How this makes the solution composible is beyond my understanding. Here is what I tried but I get compile errors as follows: Couldn't match expected type `GameValue -> StateT GameState Data.Functor.Identity.Identity b0' with actual type `State GameState GameValue' In the second argument of `(>>=)', namely `g2' In the expression: g1 >>= g2 In an equation for `g3': g3 = g1 >>= g2 Failed, modules loaded: none. Here is the code: See the end lines module StateGame where import Control.Monad.State type GameValue = Int type GameState = (Bool, Int) -- suppose I want to play one game after the other g1 = playGame "abcaaacbbcabbab" g2 = playGame "abcaaacbbcabb" g3 = g1 >>= g2 m2 = print $ evalState g3 startState playGame :: String -> State GameState GameValue playGame [] = do (_, score) <- get return score playGame (x:xs) = do (on, score) <- get case x of 'a' | on -> put (on, score + 1) 'b' | on -> put (on, score - 1) 'c' -> put (not on, score) _ -> put (on, score) playGame xs startState = (False, 0) main str = print $ evalState (playGame str) startState

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  • "'Objects' may not respond to 'functions'" warnings.

    - by Andrew
    Hello all, for the last couple of weeks I've finally gotten into Obj-C from regular C and have started my first app. I've watched tutorials and read through a book along with a lot of webpages, but I know I've only just begun. Anyway, for most of the night and this morning, I've been trying to get this code to work, and now that it will compile, I have a few warnings. I've searched and found similar problems with solutions, but still no dice. What I'm trying to do is put an array made from a txt document into the popup list in a combo box. AwesomeBoxList.h: #import <Cocoa/Cocoa.h> @interface AwesomeBoxList : NSObject { IBOutlet NSComboBox *ComboBoz; } -(NSArray *) getStringzFromTxtz; - (void) awesomeBoxList; @end AwesomeBoxList.m: #import "AwesomeBoxList.h" @implementation AwesomeBoxList -(NSArray *)getStringzFromTxtz { ... return combind; } - (void) awesomeBoxList { [ComboBoz setUsesDataSource:YES]; [ComboBoz setDataSource: [ComboBoz getStringzFromTxtz]: //'NSComboBox' may not respond to 'getStringzFromTxtz' [ComboBoz comboBox:(NSComboBox *)ComboBoz objectValueForItemAtIndex: [ComboBoz numberOfItemsInComboBox:(NSComboBox *)ComboBoz]]]; /*'NSComboBox' may not respond to '-numberOfItemsInComboBox:' 'NSComboBox' may not respond to '-comboBox:objectValueForItemAtIndex:' 'NSComboBox' may not respond to '-setDataSource:' */ } @end So, with all of these errors and my still shallow knowledge of Obj-C, I must be making some sort of n00b mistake. Thanks for the help.

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  • Static member function pointer to hold non static member function

    - by user1425406
    This has defeated me. I want to have a static class variable which is a pointer to a (non-static) member function. I've tried all sorts of ways, but with no luck (including using typedefs, which just seemed to give me a different set of errors). In the code below I have the static class function pointer funcptr, and I can call it successfully from outside the class, but not from within the member function CallFuncptr - which is what I want to do. Any suggestions? #include <stdio.h> class A { public: static int (A::*funcptr)(); int Four() { return 4;}; int CallFuncptr() { return (this->*funcptr)(); } // doesn't link - undefined reference to `A::funcptr' }; int (A::*funcptr)() = &A::Four; int main() { A fred; printf("four? %d\n", (fred.*funcptr)()); // This works printf("four? %d\n", fred.CallFuncptr()); // But this is the way I want to call it }

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  • Referencing java resource files for cold fusion

    - by Chimeara
    I am using a .Jar file containing a .properties file in my CF code, however it seems unable to find the .properties file when run from CF. My java code is: String key =""; String value =""; try { File file = new File("src/test.properties"); FileInputStream fileInput = new FileInputStream(file); Properties properties = new Properties(); properties.load(fileInput); fileInput.close(); Enumeration enuKeys = properties.keys(); while (enuKeys.hasMoreElements()) { key = (String) enuKeys.nextElement(); value = properties.getProperty(key); //System.out.println(key + ": " + value); } } catch (FileNotFoundException e) { e.printStackTrace(); key ="error"; } catch (IOException e) { e.printStackTrace(); key ="error"; } return(key + ": " + value); I have my test.properties file in the project src folder, and make sure it is selected when compiling, when run from eclipse it gives the expected key and value, however when run from CF I get the caught errors. My CF code is simply: propTest = CreateObject("java","package.class"); testResults = propTest.main2(); Is there a special way to reference the .properties file so CF can access it, or do I need to include the file outside the .jar somewhere?

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