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• Need some help deciphering a line of assembler code, from .NET JITted code

  - by Lasse V. Karlsen

  In a C# constructor, that ends up with a call to this(...), the actual call gets translated to this: 0000003d call dword ptr ds:[199B88E8h] What is the DS register contents here? I know it's the data-segment, but is this call through a VMT-table or similar? I doubt it though, since this(...) wouldn't be a call to a virtual method, just another constructor. I ask because the value at that location seems to be bad in some way, if I hit F11, trace into (Visual Studio 2008), on that call-instruction, the program crashes with an access violation. The code is deep inside a 3rd party control library, where, though I have the source code, I don't have the assemblies compiled with enough debug information that I can trace it through C# code, only through the disassembler, and then I have to match that back to the actual code. The C# code in question is this: public AxisRangeData(AxisRange range) : this(range, range.Axis) { } Reflector shows me this IL code: .maxstack 8 L_0000: ldarg.0 L_0001: ldarg.1 L_0002: ldarg.1 L_0003: callvirt instance class DevExpress.XtraCharts.AxisBase DevExpress.XtraCharts.AxisRange::get_Axis() L_0008: call instance void DevExpress.XtraCharts.Native.AxisRangeData::.ctor(class DevExpress.XtraCharts.ChartElement, class DevExpress.XtraCharts.AxisBase) L_000d: ret It's that last call there, to the other constructor of the same class, that fails. The debugger never surfaces inside the other method, it just crashes. The disassembly for the method after JITting is this: 00000000 push ebp 00000001 mov ebp,esp 00000003 sub esp,14h 00000006 mov dword ptr [ebp-4],ecx 00000009 mov dword ptr [ebp-8],edx 0000000c cmp dword ptr ds:[18890E24h],0 00000013 je 0000001A 00000015 call 61843511 0000001a mov eax,dword ptr [ebp-4] 0000001d mov dword ptr [ebp-0Ch],eax 00000020 mov eax,dword ptr [ebp-8] 00000023 mov dword ptr [ebp-10h],eax 00000026 mov ecx,dword ptr [ebp-8] 00000029 cmp dword ptr [ecx],ecx 0000002b call dword ptr ds:[1889D0DCh] // range.Axis 00000031 mov dword ptr [ebp-14h],eax 00000034 push dword ptr [ebp-14h] 00000037 mov edx,dword ptr [ebp-10h] 0000003a mov ecx,dword ptr [ebp-0Ch] 0000003d call dword ptr ds:[199B88E8h] // this(range, range.Axis)? 00000043 nop 00000044 mov esp,ebp 00000046 pop ebp 00000047 ret Basically what I'm asking is this: What the purpose of the ds:[ADDR] indirection here? VMT-table is only for virtual isn't it? and this is constructor Could the constructor have yet to be JITted, which could mean that the call would actually call through a JIT shim? I'm afraid I'm in deep water here, so anything might and could help. Edit: Well, the problem just got worse, or better, or whatever. We are developing the .NET feature in a C# project in a Visual Studio 2008 solution, and debugging and developing through Visual Studio. However, in the end, this code will be loaded into a .NET runtime hosted by a Win32 Delphi application. In order to facilitate easy experimentation of such features, we can also configure the Visual Studio project/solution/debugger to copy the produced dll's to the Delphi app's directory, and then execute the Delphi app, through the Visual Studio debugger. Turns out, the problem goes away if I run the program outside of the debugger, but during debugging, it crops up, every time. Not sure that helps, but since the code isn't slated for production release for another 6 months or so, then it takes some of the pressure off of it for the test release that we have soon. I'll dive into the memory parts later, but probably not until over the weekend, and post a followup.

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• C# SQLite file import prevent duplicates

  - by jakesankey

  Hi, I am attempting to get a directory (which is ever-growing) full of .txt comma delimited files to import into my SQLite db. I now have all of the files importing ok, however I need to have some way of excluding the files that have been previously added to db. I have a column in the db called FileName where the name and extension are stored next to each record from each file. Now I need to say 'If the code finds XXX.txt and XXX.txt is already in db, then skip this file'. Can I somehow add this logic to the getfiles command or is there another easy way? using (SQLiteCommand insertCommand = con.CreateCommand()) { SQLiteCommand cmdd = con.CreateCommand(); string[] files = Directory.GetFiles(@"C:\Documents and Settings\js91162\Desktop\", "R303717*.txt*", SearchOption.AllDirectories); foreach (string file in files) { string FileNameExt1 = Path.GetFileName(file); cmdd.CommandText = @" SELECT COUNT(*) FROM Import WHERE FileName = @FileExt;"; cmdd.Parameters.Add(new SQLiteParameter("@FileExt", FileNameExt1)); int count = Convert.ToInt32(cmdd.ExecuteScalar()); //int count = ((IConvertible)insertCommand.ExecuteScalar().ToInt32(null)); if (count == 0) { Console.WriteLine("Parsing CMM data for SQL database... Please wait."); insertCommand.CommandText = @" INSERT INTO Import (FeatType, FeatName, Value, Actual, Nominal, Dev, TolMin, TolPlus, OutOfTol, PartNumber, CMMNumber, Date, FileName) VALUES (@FeatType, @FeatName, @Value, @Actual, @Nominal, @Dev, @TolMin, @TolPlus, @OutOfTol, @PartNumber, @CMMNumber, @Date, @FileName);"; insertCommand.Parameters.Add(new SQLiteParameter("@FeatType", DbType.String)); insertCommand.Parameters.Add(new SQLiteParameter("@FeatName", DbType.String)); insertCommand.Parameters.Add(new SQLiteParameter("@Value", DbType.String)); insertCommand.Parameters.Add(new SQLiteParameter("@Actual", DbType.Decimal)); insertCommand.Parameters.Add(new SQLiteParameter("@Nominal", DbType.Decimal)); insertCommand.Parameters.Add(new SQLiteParameter("@Dev", DbType.Decimal)); insertCommand.Parameters.Add(new SQLiteParameter("@TolMin", DbType.Decimal)); insertCommand.Parameters.Add(new SQLiteParameter("@TolPlus", DbType.Decimal)); insertCommand.Parameters.Add(new SQLiteParameter("@OutOfTol", DbType.Decimal)); insertCommand.Parameters.Add(new SQLiteParameter("@Comment", DbType.String)); string FileNameExt = Path.GetFileName(file); string RNumber = Path.GetFileNameWithoutExtension(file); string RNumberE = RNumber.Split('_')[0]; string RNumberD = RNumber.Split('_')[1]; string RNumberDate = RNumber.Split('_')[2]; DateTime dateTime = DateTime.ParseExact(RNumberDate, "yyyyMMdd", Thread.CurrentThread.CurrentCulture); string cmmDate = dateTime.ToString("dd-MMM-yyyy"); string[] lines = File.ReadAllLines(file); bool parse = false; foreach (string tmpLine in lines) { string line = tmpLine.Trim(); if (!parse && line.StartsWith("Feat. Type,")) { parse = true; continue; } if (!parse || string.IsNullOrEmpty(line)) { continue; } Console.WriteLine(tmpLine); foreach (SQLiteParameter parameter in insertCommand.Parameters) { parameter.Value = null; } string[] values = line.Split(new[] { ',' }); for (int i = 0; i < values.Length - 1; i++) { SQLiteParameter param = insertCommand.Parameters[i]; if (param.DbType == DbType.Decimal) { decimal value; param.Value = decimal.TryParse(values[i], out value) ? value : 0; } else { param.Value = values[i]; } } insertCommand.Parameters.Add(new SQLiteParameter("@PartNumber", RNumberE)); insertCommand.Parameters.Add(new SQLiteParameter("@CMMNumber", RNumberD)); insertCommand.Parameters.Add(new SQLiteParameter("@Date", cmmDate)); insertCommand.Parameters.Add(new SQLiteParameter("@FileName", FileNameExt)); // insertCommand.ExecuteNonQuery(); } } } Console.WriteLine("CMM data successfully imported to SQL database..."); } con.Close(); }

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• Paging, sorting and filtering in a stored procedure (SQL Server)

  - by Fruitbat

  I was looking at different ways of writing a stored procedure to return a "page" of data. This was for use with the asp ObjectDataSource, but it could be considered a more general problem. The requirement is to return a subset of the data based on the usual paging paremeters, startPageIndex and maximumRows, but also a sortBy parameter to allow the data to be sorted. Also there are some parameters passed in to filter the data on various conditions. One common way to do this seems to be something like this: [Method 1] ;WITH stuff AS ( SELECT CASE WHEN @SortBy = 'Name' THEN ROW_NUMBER() OVER (ORDER BY Name) WHEN @SortBy = 'Name DESC' THEN ROW_NUMBER() OVER (ORDER BY Name DESC) WHEN @SortBy = ... ELSE ROW_NUMBER() OVER (ORDER BY whatever) END AS Row, ., ., ., FROM Table1 INNER JOIN Table2 ... LEFT JOIN Table3 ... WHERE ... (lots of things to check) ) SELECT * FROM stuff WHERE (Row > @startRowIndex) AND (Row <= @startRowIndex + @maximumRows OR @maximumRows <= 0) ORDER BY Row One problem with this is that it doesn't give the total count and generally we need another stored procedure for that. This second stored procedure has to replicate the parameter list and the complex WHERE clause. Not nice. One solution is to append an extra column to the final select list, (SELECT COUNT(*) FROM stuff) AS TotalRows. This gives us the total but repeats it for every row in the result set, which is not ideal. [Method 2] An interesting alternative is given here (http://www.4guysfromrolla.com/articles/032206-1.aspx) using dynamic SQL. He reckons that the performance is better because the CASE statement in the first solution drags things down. Fair enough, and this solution makes it easy to get the totalRows and slap it into an output parameter. But I hate coding dynamic SQL. All that 'bit of SQL ' + STR(@parm1) +' bit more SQL' gubbins. [Method 3] The only way I can find to get what I want, without repeating code which would have to be synchronised, and keeping things reasonably readable is to go back to the "old way" of using a table variable: DECLARE @stuff TABLE (Row INT, ...) INSERT INTO @stuff SELECT CASE WHEN @SortBy = 'Name' THEN ROW_NUMBER() OVER (ORDER BY Name) WHEN @SortBy = 'Name DESC' THEN ROW_NUMBER() OVER (ORDER BY Name DESC) WHEN @SortBy = ... ELSE ROW_NUMBER() OVER (ORDER BY whatever) END AS Row, ., ., ., FROM Table1 INNER JOIN Table2 ... LEFT JOIN Table3 ... WHERE ... (lots of things to check) SELECT * FROM stuff WHERE (Row > @startRowIndex) AND (Row <= @startRowIndex + @maximumRows OR @maximumRows <= 0) ORDER BY Row (Or a similar method using an IDENTITY column on the table variable). Here I can just add a SELECT COUNT on the table variable to get the totalRows and put it into an output parameter. I did some tests and with a fairly simple version of the query (no sortBy and no filter), method 1 seems to come up on top (almost twice as quick as the other 2). Then I decided to test probably I needed the complexity and I needed the SQL to be in stored procedures. With this I get method 1 taking nearly twice as long as the other 2 methods. Which seems strange. Is there any good reason why I shouldn't spurn CTEs and stick with method 3? UPDATE - 15 March 2012 I tried adapting Method 1 to dump the page from the CTE into a temporary table so that I could extract the TotalRows and then select just the relevant columns for the resultset. This seemed to add significantly to the time (more than I expected). I should add that I'm running this on a laptop with SQL Server Express 2008 (all that I have available) but still the comparison should be valid. I looked again at the dynamic SQL method. It turns out I wasn't really doing it properly (just concatenating strings together). I set it up as in the documentation for sp_executesql (with a parameter description string and parameter list) and it's much more readable. Also this method runs fastest in my environment. Why that should be still baffles me, but I guess the answer is hinted at in Hogan's comment.

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• Can a conforming C implementation #define NULL to be something wacky

  - by janks

  I'm asking because of the discussion that's been provoked in this thread: http://stackoverflow.com/questions/2597142/when-was-the-null-macro-not-0/2597232 Trying to have a serious back-and-forth discussion using comments under other people's replies is not easy or fun. So I'd like to hear what our C experts think without being restricted to 500 characters at a time. The C standard has precious few words to say about NULL and null pointer constants. There's only two relevant sections that I can find. First: 3.2.2.3 Pointers An integral constant expression with the value 0, or such an expression cast to type void * , is called a null pointer constant. If a null pointer constant is assigned to or compared for equality to a pointer, the constant is converted to a pointer of that type. Such a pointer, called a null pointer, is guaranteed to compare unequal to a pointer to any object or function. and second: 4.1.5 Common definitions <stddef.h> The macros are NULL which expands to an implementation-defined null pointer constant; The question is, can NULL expand to an implementation-defined null pointer constant that is different from the ones enumerated in 3.2.2.3? In particular, could it be defined as: #define NULL __builtin_magic_null_pointer Or even: #define NULL ((void*)-1) My reading of 3.2.2.3 is that it specifies that an integral constant expression of 0, and an integral constant expression of 0 cast to type void* must be among the forms of null pointer constant that the implementation recognizes, but that it isn't meant to be an exhaustive list. I believe that the implementation is free to recognize other source constructs as null pointer constants, so long as no other rules are broken. So for example, it is provable that #define NULL (-1) is not a legal definition, because in if (NULL) do_stuff(); do_stuff() must not be called, whereas with if (-1) do_stuff(); do_stuff() must be called; since they are equivalent, this cannot be a legal definition of NULL. But the standard says that integer-to-pointer conversions (and vice-versa) are implementation-defined, therefore it could define the conversion of -1 to a pointer as a conversion that produces a null pointer. In which case if ((void*)-1) would evaluate to false, and all would be well. So what do other people think? I'd ask for everybody to especially keep in mind the "as-if" rule described in 2.1.2.3 Program execution. It's huge and somewhat roundabout, so I won't paste it here, but it essentially says that an implementation merely has to produce the same observable side-effects as are required of the abstract machine described by the standard. It says that any optimizations, transformations, or whatever else the compiler wants to do to your program are perfectly legal so long as the observable side-effects of the program aren't changed by them. So if you are looking to prove that a particular definition of NULL cannot be legal, you'll need to come up with a program that can prove it. Either one like mine that blatantly breaks other clauses in the standard, or one that can legally detect whatever magic the compiler has to do to make the strange NULL definition work. Steve Jessop found an example of way for a program to detect that NULL isn't defined to be one of the two forms of null pointer constants in 3.2.2.3, which is to stringize the constant: #define stringize_helper(x) #x #define stringize(x) stringize_helper(x) Using this macro, one could puts(stringize(NULL)); and "detect" that NULL does not expand to one of the forms in 3.2.2.3. Is that enough to render other definitions illegal? I just don't know. Thanks!

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• MouseMotionListener inside JTable

  - by Harish

  I am trying to add MouseMotion event to the label and move it based on the dragging of the mouse and make it move along with my mouse.However the mousemotion is very difficult to control making this action not usable. Here is the code import java.awt.Color; import java.awt.Component; import java.awt.event.MouseEvent; import java.awt.event.MouseMotionListener; import javax.swing.BorderFactory; import javax.swing.JFrame; import javax.swing.JLabel; import javax.swing.JScrollPane; import javax.swing.JTable; import javax.swing.SwingConstants; import javax.swing.SwingUtilities; import javax.swing.table.DefaultTableCellRenderer; import javax.swing.table.DefaultTableModel; public class TableTest { public TableTest() { String[] columnNames = { "FileName", "Integer" }; Object[][] data = { { new FileName("AAA.jpg", Color.YELLOW), new Integer(2) }, { new FileName("BBB.png", Color.GREEN), new FileName("BBB.png", Color.GREEN) }, { new FileName("CCC.jpg", Color.RED), new Integer(-1) }, }; DefaultTableModel model = new DefaultTableModel(data, columnNames) { public Class getColumnClass(int column) { System.out.println("column is" + column); return getValueAt(0, column).getClass(); } }; JTable table = new JTable(model); //JTable table = new JTable(data, columnNames); table.setDefaultRenderer(FileName.class, new FileNameCellRenderer()); final JLabel label = new JLabel("TESTING", SwingConstants.CENTER); label.setBackground(java.awt.Color.RED); label.setBounds(450, 100, 90, 20); label.setOpaque(true); label.setVisible(true); label.addMouseMotionListener(new MouseMotionListener() { public void mouseDragged(MouseEvent arg0) { label.setBounds(arg0.getX(), arg0.getY(), 90, 20); } public void mouseMoved(MouseEvent arg0) { // TODO Auto-generated method stub } }); table.add(label); JFrame frame = new JFrame(); frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); frame.getContentPane().add(table); frame.setSize(800, 600); frame.setLocationRelativeTo(null); frame.setVisible(true); } static class FileNameCellRenderer extends DefaultTableCellRenderer { public Component getTableCellRendererComponent(JTable table, Object v, boolean isSelected, boolean hasFocus, int row, int column) { super.getTableCellRendererComponent(table, v, isSelected, hasFocus, row, column); FileName fn = (FileName) v; setBorder(BorderFactory.createMatteBorder(0, 60, 0, 0, new java.awt.Color(143, 188, 143))); return this; } } static class FileName { public final Color color; public final String label; FileName(String l, Color c) { this.label = l; this.color = c; } public String toString() { return label; } } public static void main(String[] args) { SwingUtilities.invokeLater(new Runnable() { public void run() { new TableTest(); } }); } } I just want to make the label follow the label follow my mouse and the label should be attached to the table.Is there an easy way than this.

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• Is it possible to embed Cockburn style textual UML Use Case content in the code base to improve code

  - by fooledbyprimes

  experimenting with Cockburn use cases in code I was writing some complicated UI code. I decided to employ Cockburn use cases with fish,kite,and sea levels (discussed by Martin Fowler in his book 'UML Distilled'). I wrapped Cockburn use cases in static C# objects so that I could test logical conditions against static constants which represented steps in a UI workflow. The idea was that you could read the code and know what it was doing because the wrapped objects and their public contants gave you ENGLISH use cases via namespaces. Also, I was going to use reflection to pump out error messages that included the described use cases. The idea is that the stack trace could include some UI use case steps IN ENGLISH.... It turned out to be a fun way to achieve a mini,psuedo light-weight Domain Language but without having to write a DSL compiler. So my question is whether or not this is a good way to do this? Has anyone out there ever done something similar? c# example snippets follow Assume we have some aspx page which has 3 user controls (with lots of clickable stuff). User must click on stuff in one particular user control (possibly making some kind of selection) and then the UI must visually cue the user that the selection was successful. Now, while that item is selected, the user must browse through a gridview to find an item within one of the other user controls and then select something. This sounds like an easy thing to manage but the code can get ugly. In my case, the user controls all sent event messages which were captured by the main page. This way, the page acted like a central processor of UI events and could keep track of what happens when the user is clicking around. So, in the main aspx page, we capture the first user control's event. using MyCompany.MyApp.Web.UseCases; protected void MyFirstUserControl_SomeUIWorkflowRequestCommingIn(object sender, EventArgs e) { // some code here to respond and make "state" changes or whatever // // blah blah blah // finally we have this (how did we know to call fish level method?? because we knew when we wrote the code to send the event in the user control) UpdateUserInterfaceOnFishLevelUseCaseGoalSuccess(FishLevel.SomeNamedUIWorkflow.SelectedItemForPurchase) } protected void UpdateUserInterfaceOnFishLevelGoalSuccess(FishLevel.SomeNamedUIWorkflow goal) { switch (goal) { case FishLevel.SomeNamedUIWorkflow.NewMasterItemSelected: //call some UI related methods here including methods for the other user controls if necessary.... break; case FishLevel.SomeNamedUIWorkFlow.DrillDownOnDetails: //call some UI related methods here including methods for the other user controls if necessary.... break; case FishLevel.SomeNamedUIWorkFlow.CancelMultiSelect: //call some UI related methods here including methods for the other user controls if necessary.... break; // more cases... } } } //also we have protected void UpdateUserInterfaceOnSeaLevelGoalSuccess(SeaLevel.SomeNamedUIWorkflow goal) { switch (goal) { case SeaLevel.CheckOutWorkflow.ChangedCreditCard: // do stuff // more cases... } } } So, in the MyCompany.MyApp.Web.UseCases namespace we might have code like this: class SeaLevel... class FishLevel... class KiteLevel... The workflow use cases embedded in the classes could be inner classes or static methods or enumerations or whatever gives you the cleanest namespace. I can't remember what I did originally but you get the picture.

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• Forcing a transaction to rollback on validation errors in Seam

  - by Chris Williams

  Quick version: We're looking for a way to force a transaction to rollback when specific situations occur during the execution of a method on a backing bean but we'd like the rollback to happen without having to show the user a generic 500 error page. Instead, we'd like the user to see the form she just submitted and a FacesMessage that indicates what the problem was. Long version: We've got a few backing beans that use components to perform a few related operations in the database (using JPA/Hibernate). During the process, an error can occur after some of the database operations have happened. This could be for a few different reasons but for this question, let's assume there's been a validation error that is detected after some DB writes have happened that weren't detectible before the writes occurred. When this happens, we'd like to make sure all of the db changes up to this point will be rolled back. Seam can deal with this because if you throw a RuntimeException out of the current FacesRequest, Seam will rollback the current transaction. The problem with this is that the user is shown a generic error page. In our case, we'd actually like the user to be shown the page she was on with a descriptive message about what went wrong, and have the opportunity to correct the bad input that caused the problem. The solution we've come up with is to throw an Exception from the component that discovers the validation problem with the annotation: @ApplicationException( rollback = true ) Then our backing bean can catch this exception, assume the component that threw it has published the appropriate FacesMessage, and simply return null to take the user back to the input page with the error displayed. The ApplicationException annotation tells Seam to rollback the transaction and we're not showing the user a generic error page. This worked well for the first place we used it that happened to only be doing inserts. The second place we tried to use it, we have to delete something during the process. In this second case, everything works if there's no validation error. If a validation error does happen, the rollback Exception is thrown and the transaction is marked for rollback. Even if no database modifications have happened to be rolled back, when the user fixes the bad data and re-submits the page, we're getting: java.lang.IllegalArgumentException: Removing a detached instance The detached instance is lazily loaded from another object (there's a many to one relationship). That parent object is loaded when the backing bean is instantiated. Because the transaction was rolled back after the validation error, the object is now detached. Our next step was to change this page from conversation scope to page scope. When we did this, Seam can't even render the page after the validation error because our page has to hit the DB to render and the transaction has been marked for rollback. So my question is: how are other people dealing with handling errors cleanly and properly managing transactions at the same time? Better yet, I'd love to be able to use everything we have now if someone can spot something I'm doing wrong that would be relatively easy to fix. I've read the Seam Framework article on Unified error page and exception handling but this is geared more towards more generic errors your application might encounter.

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• Why does this valid Tkinter code crash when mixed with a bit of PyWin32?

  - by Erlog

  So I'm making a very small program for personal use in tkinter, and I've run into a really strange wall. I'm mixing tkinter with the pywin32 bindings because I really hate everything to do with the syntax and naming conventions of pywin32, and it feels like tkinter gets more done with far less code. The strangeness is happening in the transition between the pywin32 clipboard watching and my program's reaction to it in tkinter. My window and all its controls are being handled in tkinter. The pywin32 bindings are doing clipboard watching and clipboard access when the clipboard changes. From what I've gathered about the way the clipboard watching pieces of pywin32 work, you can make it work with anything you want as long as you provide pywin32 with the hwnd value of your window. I'm doing that part, and it works when the program first starts. It just doesn't seem to work when the clipboard changes. When the program launches, it grabs the clipboard and puts it into the search box and edit box just fine. When the clipboard is modified, the event I want to fire off is firing off...except that event that totally worked before when the program launched is now causing a weird hang instead of doing what it's supposed to do. I can print the clipboard contents to stdout all I want if the clipboard changes, but not put that same data into a tkinter widget. It only hangs like that if it starts to interact with any of my tkinter widgets after being fired off by a clipboard change notification. It feels like there's some pywin32 etiquette I've missed in adapting the clipboard-watching sample code I was using over to my tkinter-using program. Tkinter apparently doesn't like to produce stack traces or error messages, and I can't really even begin to know what to look for trying to debug it with pdb. Here's the code: #coding: utf-8 #Clipboard watching cribbed from ## {{{ http://code.activestate.com/recipes/355593/ (r1) import pdb from Tkinter import * import win32clipboard import win32api import win32gui import win32con import win32clipboard def force_unicode(object, encoding="utf-8"): if isinstance(object, basestring) and not isinstance(object, unicode): object = unicode(object, encoding) return object class Application(Frame): def __init__(self, master=None): self.master = master Frame.__init__(self, master) self.pack() self.createWidgets() self.hwnd = self.winfo_id() self.nextWnd = None self.first = True self.oldWndProc = win32gui.SetWindowLong(self.hwnd, win32con.GWL_WNDPROC, self.MyWndProc) try: self.nextWnd = win32clipboard.SetClipboardViewer(self.hwnd) except win32api.error: if win32api.GetLastError () == 0: # information that there is no other window in chain pass else: raise self.update_search_box() self.word_search() def word_search(self): #pdb.set_trace() term = self.searchbox.get() self.resultsbox.insert(END, term) def update_search_box(self): clipboardtext = "" if win32clipboard.IsClipboardFormatAvailable(win32clipboard.CF_TEXT): win32clipboard.OpenClipboard() clipboardtext = win32clipboard.GetClipboardData() win32clipboard.CloseClipboard() if clipboardtext != "": self.searchbox.delete(0,END) clipboardtext = force_unicode(clipboardtext) self.searchbox.insert(0, clipboardtext) def createWidgets(self): self.button = Button(self) self.button["text"] = "Search" self.button["command"] = self.word_search self.searchbox = Entry(self) self.resultsbox = Text(self) #Pack everything down here for "easy" layout changes later self.searchbox.pack() self.button.pack() self.resultsbox.pack() def MyWndProc (self, hWnd, msg, wParam, lParam): if msg == win32con.WM_CHANGECBCHAIN: self.OnChangeCBChain(msg, wParam, lParam) elif msg == win32con.WM_DRAWCLIPBOARD: self.OnDrawClipboard(msg, wParam, lParam) # Restore the old WndProc. Notice the use of win32api # instead of win32gui here. This is to avoid an error due to # not passing a callable object. if msg == win32con.WM_DESTROY: if self.nextWnd: win32clipboard.ChangeClipboardChain (self.hwnd, self.nextWnd) else: win32clipboard.ChangeClipboardChain (self.hwnd, 0) win32api.SetWindowLong(self.hwnd, win32con.GWL_WNDPROC, self.oldWndProc) # Pass all messages (in this case, yours may be different) on # to the original WndProc return win32gui.CallWindowProc(self.oldWndProc, hWnd, msg, wParam, lParam) def OnChangeCBChain (self, msg, wParam, lParam): if self.nextWnd == wParam: # repair the chain self.nextWnd = lParam if self.nextWnd: # pass the message to the next window in chain win32api.SendMessage (self.nextWnd, msg, wParam, lParam) def OnDrawClipboard (self, msg, wParam, lParam): if self.first: self.first = False else: #print "changed" self.word_search() #self.word_search() if self.nextWnd: # pass the message to the next window in chain win32api.SendMessage(self.nextWnd, msg, wParam, lParam) if __name__ == "__main__": root = Tk() app = Application(master=root) app.mainloop() root.destroy()

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• Design Question - how do you break the dependency between classes using an interface?

  - by Seth Spearman

  Hello, I apologize in advance but this will be a long question. I'm stuck. I am trying to learn unit testing, C#, and design patterns - all at once. (Maybe that's my problem.) As such I am reading the Art of Unit Testing (Osherove), and Clean Code (Martin), and Head First Design Patterns (O'Reilly). I am just now beginning to understand delegates and events (which you would see if you were to troll my SO questions of recent). I still don't quite get lambdas. To contextualize all of this I have given myself a learning project I am calling goAlarms. I have an Alarm class with members you'd expect (NextAlarmTime, Name, AlarmGroup, Event Trigger etc.) I wanted the "Timer" of the alarm to be extensible so I created an IAlarmScheduler interface as follows... public interface AlarmScheduler { Dictionary<string,Alarm> AlarmList { get; } void Startup(); void Shutdown(); void AddTrigger(string triggerName, string groupName, Alarm alarm); void RemoveTrigger(string triggerName); void PauseTrigger(string triggerName); void ResumeTrigger(string triggerName); void PauseTriggerGroup(string groupName); void ResumeTriggerGroup(string groupName); void SetSnoozeTrigger(string triggerName, int duration); void SetNextOccurrence (string triggerName, DateTime nextOccurrence); } This IAlarmScheduler interface define a component that will RAISE an alarm (Trigger) which will bubble up to my Alarm class and raise the Trigger Event of the alarm itself. It is essentially the "Timer" component. I have found that the Quartz.net component is perfectly suited for this so I have created a QuartzAlarmScheduler class which implements IAlarmScheduler. All that is fine. My problem is that the Alarm class is abstract and I want to create a lot of different KINDS of alarm. For example, I already have a Heartbeat alarm (triggered every (int) interval of minutes), AppointmentAlarm (triggered on set date and time), Daily Alarm (triggered every day at X) and perhaps others. And Quartz.NET is perfectly suited to handle this. My problem is a design problem. I want to be able to instantiate an alarm of any kind without my Alarm class (or any derived classes) knowing anything about Quartz. The problem is that Quartz has awesome factories that return just the right setup for the Triggers that will be needed by my Alarm classes. So, for example, I can get a Quartz trigger by using TriggerUtils.MakeMinutelyTrigger to create a trigger for the heartbeat alarm described above. Or TriggerUtils.MakeDailyTrigger for the daily alarm. I guess I could sum it up this way. Indirectly or directly I want my alarm classes to be able to consume the TriggerUtils.Make* classes without knowing anything about them. I know that is a contradiction, but that is why I am asking the question. I thought about putting a delegate field into the alarm which would be assigned one of these Make method but by doing that I am creating a hard dependency between alarm and Quartz which I want to avoid for both unit testing purposes and design purposes. I thought of using a switch for the type in QuartzAlarmScheduler per here but I know it is bad design and I am trying to learn good design. If I may editorialize a bit. I've decided that coding (predefined) classes is easy. Design is HARD...in fact, really hard and I am really fighting feeling stupid right now. I guess I want to know if you really smart people took a while to really understand and master this stuff or should I feel stupid (as I do) because I haven't grasped it better in the couple of weeks/months I have been studying. You guys are awesome and thanks in advance for your answers. Seth

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• Is this a right way to use NHibernate?

  - by Venemo

  I spent the rest of the evening reading StackOverflow questions and also some blog entries and links about the subject. All of them turned out to be very helpful, but I still feel that they don't really answer my question. So, I'm developing a simple web application. I'd like to create a reusable data access layer which I can later reuse in other solutions. 99% of these will be web applications. This seems to be a good excuse for me to learn NHibernate and some of the patterns around it. My goals are the following: I don't want the business logic layer to know ANYTHING about the inner workings of the database, nor NHibernate itself. I want the business logic layer to have the least possible number of assumptions about the data access layer. I want the data access layer as simplistic and easy-to-use as possible. This is going to be a simple project, so I don't want to overcomplicate anything. I want the data access layer to be as non-intrusive as possible. Will all this in mind, I decided to use the popular repository pattern. I read about this subject on this site and on various dev blogs, and I heard some stuff about the unit of work pattern. I also looked around and checked out various implementations. (Including FubuMVC contrib, and SharpArchitecture, and stuff on some blogs.) I found out that most of these operate with the same principle: They create a "unit of work" which is instantiated when a repository is instantiated, they start a transaction, do stuff, and commit, and then start all over again. So, only one ISession per Repository and that's it. Then the client code needs to instantiate a repository, do stuff with it, and then dispose. This usage pattern doesn't meet my need of being as simplistic as possible, so I began thinking about something else. I found out that NHibernate already has something which makes custom "unit of work" implementations unnecessary, and that is the CurrentSessionContext class. If I configure the session context correctly, and do the clean up when necessary, I'm good to go. So, I came up with this: I have a static class called NHibernateHelper. Firstly, it has a static property called CurrentSessionFactory, which upon first call, instantiates a session factory and stores it in a static field. (One ISessionFactory per one AppDomain is good enough.) Then, more importantly, it has a CurrentSession static property, which checks if there is an ISession bound to the current session context, and if not, creates one, and binds it, and it returns with the ISession bound to the current session context. Because it will be used mostly with WebSessionContext (so, one ISession per HttpRequest, although for the unit tests, I configured ThreadStaticSessionContext), it should work seamlessly. And after creating and binding an ISession, it hooks an event handler to the HttpContext.Current.ApplicationInstance.EndRequest event, which takes care of cleaning up the ISession after the request ends. (Of course, it only does this if it is really running in a web environment.) So, with all this set up, the NHibernateHelper will always be able to return a valid ISession, so there is no need to instantiate a Repository instance for the "unit of work" to operate properly. Instead, the Repository is a static class which operates with the ISession from the NHibernateHelper.CurrentSession property, and exposes some functionality through that. I'm curious, what do you think about this? Is it a valid way of thinking, or am I completely off track here?

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• How to remove a model object from an EMF model and its GEF Editor via Adapter

  - by s.d

  This question is principally a follow-up to my question about EMF listening mechanisms. So, I have a third-party EMF model (uneditable) which is based on a generic graph model. The structure is as follows: Project | ItemGraph | Item | Document | DocumentGraph / | \ Tokens Nodes Relations(Edges) I have a GEF editor which works on the DocumentGraph (i.e., not the root object, perhaps this is a problem?): getGraphicalViewer().setContents(documentGraph). THe editor has the following edit part structure: DocumentGraphEP / \ Primary Connection LayerEP LayerEP / \ | TokenEP NodeEP RelationEP PrimaryLayerEP and ConnectionLayerEP both have simple Strings as model, which are not represented in the EMF (domain) model. They are simply used to add a primary (i.e., node) layer, and a connection layer (with ShortestPathConnectionRouter) to the editor. Problem: I am trying to get myself into the workings of EMF adapters, and have tried to make use of the available tutorials, mainly the EMF-GEF Eclipse tutorial, vainolo's blog, and vogella's tutorial. I thought I'd start with an easy thing, so tried to remove a node from the graph and see if I get it to work. Which I didn't, and I don't see where the problem is. I can select a node, and have the generic delete Action in my toolbar, but when I click it, nothing happens. Here is the respective source code for the different responsible parts. Please be so kind to point me to any errors (of thinking, coding errors, whathaveyou) you can find. NodeEditPart public class NodeEditPart extends AbstractGraphicalEditPart implements Adapter { protected IFigure createFigure() { return new NodeFigure(); } protected void createEditPolicies() { .... installEditPolicy(EditPolicy.COMPONENT_ROLE, new NodeComponentEditPolicy()); } protected void refreshVisuals() { NodeFigure figure = (NodeFigure) getFigure(); SNode model = (SNode) getModel(); PrimaryLayerEditPart parent = (PrimaryLayerEditPart) getParent(); // Set text figure.getLabel().setText(model.getSName()); .... } public void activate() { if (isActive()) return; // start listening for changes in the model ((Notifier)getModel()).eAdapters().add(this); super.activate(); } public void deactivate() { if (!isActive()) return; // stop listening for changes in the model ((Notifier)getModel()).eAdapters().remove(this); super.deactivate(); } private Notifier getSDocumentGraph() { return ((SNode)getModel()).getSDocumentGraph(); } @Override public void notifyChanged(Notification notification) { int type = notification.getEventType(); switch( type ) { case Notification.ADD: case Notification.ADD_MANY: case Notification.REMOVE: case Notification.REMOVE_MANY: refreshChildren(); break; case Notification.SET: refreshVisuals(); break; } } @Override public Notifier getTarget() { return target; } @Override public void setTarget(Notifier newTarget) { this.target = newTarget; } @Override public boolean isAdapterForType(Object type) { return type.equals(getModel().getClass()); } } NodeComponentEditPolicy public class NodeComponentEditPolicy extends ComponentEditPolicy { public NodeComponentEditPolicy() { super(); } protected Command createDeleteCommand(GroupRequest deleteRequest) { DeleteNodeCommand cmd = new DeleteNodeCommand(); cmd.setSNode((SNode) getHost().getModel()); return cmd; } } DeleteNodeCommand public class DeleteNodeCommand extends Command { private SNode node; private SDocumentGraph graph; @Override public void execute() { node.setSDocumentGraph(null); } @Override public void undo() { node.setSDocumentGraph(graph); } public void setSNode(SNode node) { this.node = node; this.graph = node.getSDocumentGraph(); } } All seems to work fine: When a node is selected in the editor, the delete symbol is activated in the toolbar, but when it is clicked, nothing happens in the editor. I'd be very thankful for any pointers :).

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• Best way to get back to using the power of lxml after having to use a regex to find something in an

  - by PyNEwbie

  I am trying to rip some text out of a large number of html documents (numbers in the hundreds of thousands). The documents are really forms but they are prepared by a very large group of different organizations so there is significant variation in how they create the document. For example, the documents are divided into chapters. I might want to extract the contents of Chapter 5 from every document so I can analyze the content of the chapter. Initially I thought this would be easy but it turns out that the authors might use a set of non-nested tables throughout the document to hold the content so that Chapter n could be displayed using td tags inside a table. Or they might use other elements such as p tags H tags, div tags or any other block level element. After trying repeatedly to use lxml to help me identify the beginning and end of each chapter I have determined that it is a lot cleaner to use a regular expression because in every case, no matter what the enclosing html element is the chapter label is always in the form of >Chapter # It is a little more complicated in that there might be some white space or non-breaking space represented in different ways (  or   or just spaces). Nonetheless it was trivial to write a regular expression to identify the beginning of each section. (The beginning of one section is the end of the previous section.) But now I want to use lxml to get the text out. My thought is that I have really no choice but to walk along my string to find the close tag for the element that encloses the text I am using to find the relevant section. That is here is one example where the element holding the Chapter name is a div <div style="DISPLAY: block; MARGIN-LEFT: 0pt; TEXT-INDENT: 0pt; MARGIN-RIGHT: 0pt" align="left"><font style="DISPLAY: inline; FONT-WEIGHT: bold; FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman">Chapter 1.&#160;&#160;&#160;Our Beginnings.</font></div> So I am imagining that I would begin at the location where I found the match for chapter 1 and set up a regular expressions to find the next </div|</td|</p|</h1 . . . So at this point I have identified the type of element holding my chapter heading I can use the same logic to find all of the text that is within that element that is set up a regular expression to help me mark from >Chapter 1.&#160;&#160;&#160;Our Beginnings.< So I have identified where my Chapter 1 begins I can do the same for chapter 2 (which is where Chapter 1 ends) Now I am imagining that I am going to snip the document beginning at the opening of the element that I identified as the element the indicates where chapter 1 begins and ending just before the opening of the element that I identified as the element that indicates where Chapter 2 begins. The string that I have identified will then be fed to lxml to use its power to get the content. I am going to all of this trouble because I have read over and over - never use a regular expression to extract content from html documents and I have not hit on a way to be as accurate with lxml to identify the starting and ending locations for the text I want to extract. For example, I can never be certain that the subtitle of Chapter 1 is Our Beginnings it could be Our Red Canary. Let me say that I spent two solid days trying with lxml to be confident that I had the beginning and ending elements and I could only be accurate <60% of the time but a very short regular expression has given me better than 95% success. I have a tendency to make things more complicated than necessary so I am wondering if anyone has seen or solved a similar problems and if they had an approach (not the details mind you) that they would like to offer.

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• How do I get through proxy server environments for non-standard services?

  - by Ripred

  I'm not real hip on exactly what role(s) today's proxy servers can play and I'm learning so go easy on me :-) I have a client/server system I have written using a homegrown protocol and need to enhance the client side to negotiate its way out of a proxy environment. I have an existing client and server system written in C and C++ for the speed and a small amount of MFC in the client to handle the user interface. I have written both the server and client side of the system on Windows (the people I work for are mainly web developers using Windows everything - not a choice) sticking to Berkeley Sockets as it were via wsock32 for efficiency. The clients connect to the server through a nonstandard port (even though using port 80 is an option to get out of some environments but the protocol that goes over it isn't HTTP). The TCP connection(s) stay open for the duration of the clients participation in real time conferences. Our customer base is expanding to all kinds of networked environments. I have been able to solve a lot of problems by adding the ability to connect securely over port 443 and using secure sockets which allows the protocol to pass through a lot environments since the internal packets can't be sniffed. But more and more of our customers are behind a proxy server environment and my direct connections don't make it through. My old school understanding of proxy servers is that they act as a proxy for external HTML content over HTTP, possibly locally caching popular material for faster local access, and also allowing their IT staff to blacklist certain destination sites. Customer are complaining that my software doesn't recognize and easily navigate its way through their proxy environments but I'm finding it difficult to decide what my "best fit" solution should be. My software doesn't tear down the connection after each client request, and on top of that packets can come from either side at any time, basically your typical custom client/server system for a specific niche. My first reaction is "why can't they just add my servers addresses to their white list" but if there is a programmatic way I can get through without requiring their IT staff to help it is politically better and arguably a better solution anyway. Plus maybe I'm still not understanding the role and purpose of what proxy servers and environments have grown to be these days. My first attempt at a solution was to use WinInet with its various proxy capabilities to establish a connection over port 80 to my non-standard protocol server (which knows enough to recognize and answer a simple HTTP-looking GET request and answer it with a simple HTTP response page to get around some environments that employ initial packet sniffing (DPI)). I retrieved the actual SOCKET handle behind WinInet's HINTERNET request object and had hoped to use that in place of my software's existing SOCKET connection and hopefully not need to change much more on the client side. It initially seemed to be my solution but on further inspection it seems that the OS gets first-chance at the received data on this socket since when I get notified of events via the standard select(...) statement on the socket and query the size of the data available via ioctlsocket the call succeeds but returns 0 bytes available, the reads don't work and it goes downhill from there. Can someone tell me of a client-side library (commercial is fine) will let me get past these proxy server environments with as little user and IT staff help as possible? From what I read it has grown past SOCKS and I figure someone has to have solved this problem before me. Thanks for reading my long-winded question, Ripred

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• How to include the login form on the Home index page in MVC

  - by Bernard Larouche

  Hi guys I really need your help for this. I am relatively new to programming and I need help to something that could be easy for a experienced programmer. I would like to get the login form that we get for free in an MVC application on the left sidebar of my Home index page instead of the usual Account/Login page. I am facing some problems. First I need a product object to be displayed on my Home Index page as well. What I did is that I added a product object to the LogOnModel that they provide in the AccountModels class and I created a UserControl (partial view) copying the content of the LogOn.aspx view. Now my Home index.aspx as well as my partial view inherits the LogOnModel class. I can see the Login form on my Home Index page as well as my product object BUT the login Form is never empty. The last username and password always appear there. I know I must have forgotten something or have done something wrong or the way did it is completely wrong !! Please could you give me some advice Thks <%@ Control Language="C#" Inherits="System.Web.Mvc.ViewUserControl<CoderForTradersSite.Models.LogOnModel>" %> <h4>Login Form</h4> <p> Please enter your username and password. <%= Html.ActionLink("Register", "Register") %> if you don't have an account. </p> <% using (Html.BeginForm()) { %> <%= Html.ValidationSummary(true, "Login was unsuccessful. Please correct the errors and try again.") %> <div> <fieldset> <legend>Account Information</legend> <div class="editor-label"> <%= Html.LabelFor(m => m.UserName) %> </div> <div class="editor-field"> <%= Html.TextBoxFor(m => m.UserName) %> <%= Html.ValidationMessageFor(m => m.UserName) %> </div> <div class="editor-label"> <%= Html.LabelFor(m => m.Password) %> </div> <div class="editor-field"> <%= Html.PasswordFor(m => m.Password) %> <%= Html.ValidationMessageFor(m => m.Password) %> </div> <div class="editor-label"> <%= Html.CheckBoxFor(m => m.RememberMe) %> <%= Html.LabelFor(m => m.RememberMe) %> </div> <p> <input type="submit" value="Log On" /> </p> </fieldset> </div> <% } %>

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• How do I edit an XML file with Perl?

  - by thebourneid

  I have a movie collection catalogue with local links to folders and files for an easy access. Recently I reorganaized my entire hard disk space and I need to update the links and I'm trying to do that automatically with Perl. I can export the data in a XML file and import it again. I can extract the new filepaths with the use of File::Find but I'm stuck with two problems. I have no idea how to connect the $title from the new filepath with the corresponding $title from the XML file. I'm dealing with such files for the first time and I don't know how to proceed with the replacement process. Here is what I've done till now use strict; use warnings; use File::Basename; use File::Find; use File::Spec; use XML::Simple; use Data::Dumper; my $dir_target = 'D:/Movies/'; my %titles_locations = (); find(\&file_handler, $dir_target); sub file_handler { /\.iso$/ or return; my $fn = $File::Find::name; $fn =~ s/\//\\/g; $fn =~ /(.*\\)(.*)/; my $path = $1; my $filename = $2; my $title = (File::Spec->splitdir($fn))[2]; $title =~ s/(.*?)\s\(\d+\)$/$1/; $title =~ s/~/:/; $title =~ s/`/?/; my $link_local = '<link><description>Folder</description><url>'.$path.'</url><urltype>Movie</urltype></link><link><description>'.$filename.'</description><url>'.$fn.'</url><urltype>Movie</urltype></link>' unless $title eq ''; $titles_locations{$title} = {'filename'=>$filename, 'path'=>$path }; } my $xml_in = XMLin('somepath/test.xml', ForceArray => 1, KeepRoot => 1); my $title = {'key1' => 'title', 'key2' => 'links'}; foreach my $link (keys %$title) { } print Data::Dumper->Dump([$title]); my $xml_out = XMLout($xml_in, OutputFile => 'somepath/test_out.xml', KeepRoot=>1); And here is a snippet of the data I need to edit. If found imdb and dvdempire link - do not touch. if found local links replace, otherwise insert. I'm willing to complete the code myself but need some directions how to proceed further. Thanks. <title>$title</title> ....... <links> <link> <description>IMDB</description> <url>http://www.imdb.com/title/VARIABLE</url> <urltype>URL</urltype> </link> <link> <description>DVD Empire</description> <url>http://www.dvdempire.com/VARIABLE</url> <urltype>URL</urltype> </link> <link> <description>Folder</description> <url>OLD_FOLDERPATH</url> <urltype>Movie</urltype> </link> <link> <description>OLD_FILENAME</description> <url>OLD_FILENAMEPATH</url> <urltype>Movie</urltype> </link> </links>

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• How To Edit XML File

  - by thebourneid

  I have a movie collection catalogue with local links to folders and files for an easy access. Recently I reorganaized my entire hard disk space and I need to update the links and I'm trying to do that automatically with perl. I can export the data in a xml file and import it again. I can extract the new filepaths with the use of File::Find but I'm stuck with two problems. I have no idea how to connect the $title from the new filepath with the corresponding $title from the xml file. I'm dealing with such files for the first time and I don't know how to proceed with the replacement process. Here is what I've done till now use strict; use warnings; use File::Basename; use File::Find; use File::Spec; use XML::Simple; use Data::Dumper; my $dir_target = 'somepath'; find(\&a, $dir_target); sub a { /\.iso$/ or return; my $fn = $File::Find::name; $fn =~ s/\//\\/g; $fn =~ /(.*\\)(.*)/; my $path = $1; my $filename = $2; my $title = (File::Spec->splitdir($fn))[2]; $title =~ s/(.*?)\s\(\d+\)$/$1/; $title =~ s/~/:/; $title =~ s/`/?/; my $link_local = '<link><description>Folder</description><url>'.$path.'</url><urltype>Movie</urltype></link><link><description>'.$filename.'</description><url>'.$fn.'</url><urltype>Movie</urltype></link>' unless $title eq ''; my $txt = 'somepath/log.txt'; my $xml_in = XMLin('somepath/test.xml', ForceArray => 1, KeepRoot => 1); my $xml_out = XMLout($xml_in, OutputFile => 'somepath/test_out.xml', KeepRoot=>1); open F, ">>", $txt; print F $link_local."\n\n"; close F; } And here is a snippet of the data I need to edit. If found imdb and dvdempire link - do not touch. if found local links replace, otherwise insert. I'm willing to complete the code myself but need some directions how to proceed further. Thanks. <title>$title</title> ....... <links> <link> <description>IMDB</description> <url>http://www.imdb.com/title/VARIABLE</url> <urltype>URL</urltype> </link> <link> <description>DVD Empire</description> <url>http://www.dvdempire.com/VARIABLE</url> <urltype>URL</urltype> </link> <link> <description>Folder</description> <url>OLD_FOLDERPATH</url> <urltype>Movie</urltype> </link> <link> <description>OLD_FILENAME</description> <url>OLD_FILENAMEPATH</url> <urltype>Movie</urltype> </link> </links>

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• Languages and VMs: Features that are hard to optimize and why

  - by mrjoltcola

  I'm doing a survey of features in preparation for a research project. Name a mainstream language or language feature that is hard to optimize, and why the feature is or isn't worth the price paid, or instead, just debunk my theories below with anecdotal evidence. Before anyone flags this as subjective, I am asking for specific examples of languages or features, and ideas for optimization of these features, or important features that I haven't considered. Also, any references to implementations that prove my theories right or wrong. Top on my list of hard to optimize features and my theories (some of my theories are untested and are based on thought experiments): 1) Runtime method overloading (aka multi-method dispatch or signature based dispatch). Is it hard to optimize when combined with features that allow runtime recompilation or method addition. Or is it just hard, anyway? Call site caching is a common optimization for many runtime systems, but multi-methods add additional complexity as well as making it less practical to inline methods. 2) Type morphing / variants (aka value based typing as opposed to variable based) Traditional optimizations simply cannot be applied when you don't know if the type of someting can change in a basic block. Combined with multi-methods, inlining must be done carefully if at all, and probably only for a given threshold of size of the callee. ie. it is easy to consider inlining simple property fetches (getters / setters) but inlining complex methods may result in code bloat. The other issue is I cannot just assign a variant to a register and JIT it to the native instructions because I have to carry around the type info, or every variable needs 2 registers instead of 1. On IA-32 this is inconvenient, even if improved with x64's extra registers. This is probably my favorite feature of dynamic languages, as it simplifies so many things from the programmer's perspective. 3) First class continuations - There are multiple ways to implement them, and I have done so in both of the most common approaches, one being stack copying and the other as implementing the runtime to use continuation passing style, cactus stacks, copy-on-write stack frames, and garbage collection. First class continuations have resource management issues, ie. we must save everything, in case the continuation is resumed, and I'm not aware if any languages support leaving a continuation with "intent" (ie. "I am not coming back here, so you may discard this copy of the world"). Having programmed in the threading model and the contination model, I know both can accomplish the same thing, but continuations' elegance imposes considerable complexity on the runtime and also may affect cache efficienty (locality of stack changes more with use of continuations and co-routines). The other issue is they just don't map to hardware. Optimizing continuations is optimizing for the less-common case, and as we know, the common case should be fast, and the less-common cases should be correct. 4) Pointer arithmetic and ability to mask pointers (storing in integers, etc.) Had to throw this in, but I could actually live without this quite easily. My feelings are that many of the high-level features, particularly in dynamic languages just don't map to hardware. Microprocessor implementations have billions of dollars of research behind the optimizations on the chip, yet the choice of language feature(s) may marginalize many of these features (features like caching, aliasing top of stack to register, instruction parallelism, return address buffers, loop buffers and branch prediction). Macro-applications of micro-features don't necessarily pan out like some developers like to think, and implementing many languages in a VM ends up mapping native ops into function calls (ie. the more dynamic a language is the more we must lookup/cache at runtime, nothing can be assumed, so our instruction mix is made up of a higher percentage of non-local branching than traditional, statically compiled code) and the only thing we can really JIT well is expression evaluation of non-dynamic types and operations on constant or immediate types. It is my gut feeling that bytecode virtual machines and JIT cores are perhaps not always justified for certain languages because of this. I welcome your answers.

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• Form loop db insertion + javascript altering

  - by MrStatic

  I basically need to check if there is an easier way to do this before I rewrite all the code. I have a fairly large form that I have each input named with []'s on the end so I can loop through via php for easy insertion. <input type="hidden" name="currentdate[]" value="<?php echo date('mdY'); ?>"> <td><input style="width: 50px" type="text" name="jackname[]" /></td> <td><input style="width: 20px" type="text" name="jackkey[]" /></td> <td><input style="width: 50px" type="text" name="jackbeg[]" /></td> <td><input style="width: 50px" type="text" name="jackend[]" /></td> <td><input style="width: 50px" type="text" name="jackbegveh" /></td> <td><input style="width: 50px" type="text" name="jackbegmon[]" /></td> <td><input style="width: 50px" type="text" name="jackendveh" /></td> <td><input style="width: 50px" type="text" name="jackendmon[]" /></td> <td><input style="width: 50px" type="text" name="jacktx" disabled /></td> There are quite a few more fields but you get the idea. I then use foreach ($_POST['jackname'] as $row=>$name) { $jackname = $name; $date = $_POST['currentdate'][$row]; $jackkey = $_POST['jackkey'][$row]; $jackbeg = $_POST['jackbeg'][$row]; $jackend = $_POST['jackend'][$row]; $jackbegveh = $_POST['jackbegveh'][$row]; $jackbegmon = $_POST['jackbegmon'][$row]; $jackendveh = $_POST['jackendveh'][$row]; $jackendmon = $_POST['jackendmon'][$row]; $jacktx = $_POST['jacktx'][$row]; if ($jacktx == '') { $jacktx = '0'; } if (empty($jackkey)) { echo 'Skipped empty! <br />'; } else { mysql_query("INSERT INTO `ticket_counts_jackson` VALUES('', '" . $date . "', '" . $jackname . "', '" . $jackkey . "', '" . $jackbeg . "', '" . $jackend . "', '" . $jackbegveh . "', '" . $jackbegmon . "', '" . $jackendveh . "', '" . $jackendmon . "', '" . $jacktx . "')", $mysql_link) or die(mysql_error()); echo 'Added the info the db! <br />'; } } I use the above to loop through the form and add it to the database. Now for my main question. I also want to add in some javascript to do a little math. Basically ($jackendveh - $jackbegveh) - ($jackendmon - $jackbegmon) and have that displayed in jacktx. Currently the only way I know of adding in the math calculations is to rename each input to a unique name and then rewrite my insert from 1 insert to 8 inserts.

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• Decentralized synchronized secure data storage

  - by Alberich

  Introduction Hi, I am going to ask a question which seems utopic for me, but I need to know if there is a way to achieve what I need. And if not, I need to know why not. The idea Suppose I have a database structure, in MySql. I want to create some solution to allow anyone (no matter who, no matter where) to have a synchronized copy (updated clone) of this database (with its content) Well, and it is not going to be just one synchronized copy, it could (and should) be a multiple replication (supposing the basic, this means, for example, ten copies all over the world) And, the most important thing: It must be secure. By secure I mean only real-accepted transactions will be synchronized with all the others (no matter how many) database copies/clones. Note: Since it would be quite difficult to make the synchronization in real-time, I will design everything to make this feature dispensable. So it is not required. My auto-suggestion This is how I am thinking to manage it: Time identifiers and Updates checking: Every action (insert, update, delete...) will be stored as the action instruction itself, associated to the time identifier. [I think better than a DATETIME field, it'll be an INT one, with the number of miliseconds passed from 1st january 2013 on, for example]. So each copy is going to ask to the "neighbour copy" for new actions done since last update, and execute them after checking they are allowed. Problem 1: the "neighbour copy" could be outdated too. Solution 1: do not ask just one neighbour, create a random list with some of the copies/clones and ask them for news (I could avoid the list and ask ALL the clones for updates, but this will be inefficient if clones number ascends too much). Problem 2: Real-time global synchronization is not active. What if... Someone at CLONE_ENTERPRISING inserts a row into TABLE. ... this row goes to every clone ... Someone at CLONE_FIXEMALL deletes this row. ... and at the same time, somewhere in an outdated clone ... Someone at CLONE_DROPOUT edits this row (now inexistent at the other clones) Solution 2: easy stuff, force a GLOBAL synchronization before doing any new "depending-on-third-data action" (edit, for example). This global synch. will be unnecessary when making an INSERT, for instance. Note: Well, someone could have some fun, and make the same insert in two clones... since they're not getting updated in real-time, this row will exist twice. But, it's the same as when we have one single database, in some needed cases we check if there is an existing same-row before doing the final action. Not a problem. Problem 3: It is possible to edit the code and do not filter actions, so someone could spread instructions to delete everything, or just make some trolling activity. This is not a problem, since good clones will always be somewhere. Those who got bad won't interest anymore. I really appreciate if you read. I know this is not the perfect solution, it has possibly hundred of holes, but it is my basic start. I will now appreciate anything you can teach me now. Thanks a lot. PS.: It could be that all this I am trying already exists and has its own name. Sorry for asking then (I'd anyway thank this name, if it exists)

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• Recommended integration mechanism for bi-directional, authenticated, encrypted connection in C clien

  - by rcampbell

  Let me first give an example. Imagine you have a single server running a JVM application. This server keeps a collection of N equations, once for each client: Client #1: 2x Client #2: 1 + y Client #3: z/4 This server includes an HTTP interface so that random visitors can type https://www.acme.com/client/3 int their browsers and see the latest evaluated result of z/4. The tricky part is that either the client or the server may change the variable value at any time, informing the other party immediately. More specifically, Client #3 - a C app - can initially tell the server that z = 20. An hour later that same client informs the server that z = 23. Likewise the server can later inform the client that z = 28. As caf pointed out in the comments, there can be a race condition when values are changed by the client and server simultaneously. The solution would be for both client and server to send the operation performed in their message, which would need to be executed by the other party. To keep things simple, let's limit the operations to (commutative) addition, allowing us to disregard message ordering. For example, the client seeds the server with z = 20: server:z=20, client:z=20 server sends {+3} message (so z=23 locally) & client sends {-2} message (so z=18 locally) at the exact same time server receives {-2} message at some point, adds to his local copy so z=21 client receives {+3} message at some point, adds to his local copy so z=21 As long as all messages are eventually evaluated by both parties, the correct answer will eventually be given to the users of the client and server since we limited ourselves to commutative operations (addition of 3 and -2). This does mean that both client and server can be returning incorrect answers in the time it takes for messages to be exchanged and processed. While undesirable, I believe this is unavoidable. Some possible implementations of this idea include: Open an encrypted, always on TCP socket connection for communication Pros: no additional infrastructure needed, client and server know immediately if there is a problem (disconnect) with the other party, fairly straightforward (except the the encryption), native support from both JVM and C platforms Cons: pretty low-level so you end up writing a lot yourself (protocol, delivery verification, retry-on-failure logic), probably have a lot of firewall headaches during client app installation Asynchronous messaging (ex: ActiveMQ) Pros: transactional, both C & Java integration, free up the client and server apps from needing retry logic or delivery verification, pretty straightforward encryption, easy extensibility via message filters/routers/etc Cons: need additional infrastructure (message server) which must never fail, Database or file system as asynchronous integration point Same pros/cons as above but messier RESTful Web Service Pros: simple, possible reuse of the server's existing REST API, SSL figures out the encryption problem for you (maybe use RSA key a la GitHub for authentication?) Cons: Client now needs to run a C HTTP REST server w/SSL, client and server need retry logic. Axis2 has both a Java and C version, but you may be limited to SOAP. What other techniques should I be evaluating? What real world experiences have you had with these mechanisms? Which do you recommend for this problem and why?

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• Wrapping a paragraph inside a div?

  - by LOD121

  How do I make my paragraph wrap inside my div? It is currently overflowing outside of the div and I have no idea how to stop the paragraph from overflowing over the edge. I do not want a scroll bar with: overflow: scroll; and the other overflow options don't seem to help here either... I have the following code: div { width: 1200px; margin: 0 auto; } .container { overflow: hidden; } .content { width: 1000px; float: left; margin-left: 0; text-align: left; } .rightpanel { width: 190px; float: right; margin-right: 0; } <div class="container"> <div class="content"> <p>Some content flowing over more than one line</p> </div> <div class="rightpanel"> <!-- content --> </div> </div> Edit: <div class="container"> <div class="content"> <div class="leftcontent"> </div> <div class="newsfeed"> <div class="newsitem"> <p>Full age sex set feel her told. Tastes giving in passed direct me valley as supply. End great stood boy noisy often way taken short. Rent the size our more door. Years no place abode in no child my. Man pianoforte too solicitude friendship devonshire ten ask. Course sooner its silent but formal she led. Extensive he assurance extremity at breakfast. Dear sure ye sold fine sell on. Projection at up connection literature insensible motionless projecting.<br><br>Be at miss or each good play home they. It leave taste mr in it fancy. She son lose does fond bred gave lady get. Sir her company conduct expense bed any. Sister depend change off piqued one. Contented continued any happiness instantly objection yet her allowance. Use correct day new brought tedious. By come this been in. Kept easy or sons my it done.</p> </div> </div> </div> <div class="rightpanel"> </div>

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• Invoke a SOAP method with namespace prefixes

  - by mvladic

  My C# web service client sends following soap message to Java-based web service: <?xml version="1.0" encoding="utf-8"?> <soap:Envelope xmlns:soap="http://www.w3.org/2003/05/soap-envelope" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:xsd="http://www.w3.org/2001/XMLSchema"> <soap:Body> <getData> <request> <requestParameters xmlns="http://b..."> <equals> ... </equals> </requestParameters> </request> </getData> </soap:Body> </soap:Envelope> and Java-based web service returns error: 500 Internal Server Error ... Cannot find dispatch method for {}getData ... Client written in Java, which works, sends the following message: <?xml version="1.0" encoding="utf-8"?> <soap:Envelope xmlns:soap="http://www.w3.org/2003/05/soap-envelope" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:xsd="http://www.w3.org/2001/XMLSchema"> <soap:Body> <ns2:getData xmlns:ns2="http://a..."> <ns2:request> <ns3:requestParameters xmlns:ns3="http://b..."> <ns3:equals> ... </ns3:equals> </ns3:requestParameters> </ns2:request> </ns2:getData> </soap:Body> </soap:Envelope> Is there an easy way in C# to send SOAP messages the same way Java client sends: with namespace prefixes? Following is C# code that sends message: // class MyService is auto-generated using wsdl.exe tool MyService service = new MyService(); RequestMessage request = new RequestMessage(); ... ResponseMessage response = service.getData(request); ... UPDATE: RequestMessage class looks like this: /// <remarks/> [System.CodeDom.Compiler.GeneratedCodeAttribute("svcutil", "3.0.4506.2152")] [System.SerializableAttribute()] [System.Diagnostics.DebuggerStepThroughAttribute()] [System.ComponentModel.DesignerCategoryAttribute("code")] [System.Xml.Serialization.XmlTypeAttribute(Namespace="http://uri.etsi.org/02657/v1.5.1#/RetainedData")] public partial class RequestMessage { private byte[] requestPriorityField; private RequestConstraints requestParametersField; private string deliveryPointHIBField; private string maxHitsField; private NationalRequestParameters nationalRequestParametersField; private System.Xml.XmlElement anyField; /// <remarks/> [System.Xml.Serialization.XmlElementAttribute(DataType="hexBinary", Order=0)] public byte[] requestPriority { get { return this.requestPriorityField; } set { this.requestPriorityField = value; } } /// <remarks/> [System.Xml.Serialization.XmlElementAttribute(Order=1)] public RequestConstraints requestParameters { get { return this.requestParametersField; } set { this.requestParametersField = value; } } /// <remarks/> [System.Xml.Serialization.XmlElementAttribute(Order=2)] public string deliveryPointHIB { get { return this.deliveryPointHIBField; } set { this.deliveryPointHIBField = value; } } /// <remarks/> [System.Xml.Serialization.XmlElementAttribute(DataType="integer", Order=3)] public string maxHits { get { return this.maxHitsField; } set { this.maxHitsField = value; } } /// <remarks/> [System.Xml.Serialization.XmlElementAttribute(Order=4)] public NationalRequestParameters nationalRequestParameters { get { return this.nationalRequestParametersField; } set { this.nationalRequestParametersField = value; } } /// <remarks/> [System.Xml.Serialization.XmlAnyElementAttribute(Order=5)] public System.Xml.XmlElement Any { get { return this.anyField; } set { this.anyField = value; } } }

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• jQuery hide/show with select tag

  - by Ozzy

  I'm relative new to jQuery and I've been asked to create a hide/show function with a select tag. The function pretty much would be when you click on one of the options in the select tag it will open a div associate with the div of course. To be honest I have no idea how approach this function. I need help urgently, I have already tried many online but none have seem to work. Find below the html code. Thanks. <div class="adwizard"> <select id="selectdrop" name="selectdrop" class="adwizard-bullet"> <option value="adwizard">AdWizard</option> <option value="collateral">Collateral Ordering Tool</option> <option value="ebrochure">eBrochures</option> <option value="brand">Brand Center</option> <option value="funtees">FunTees</option> </select> </div> <div class="panels"> <div id="adwizard" class="sub-box showhide"> <img src="../images/bookccl/img-adwizard.gif" width="95" height="24" alt="AdWizard" /> <p>Let Carnival help you grow your business with our great tools! Lor ipsum dolor sit amet. <a href="https://www.carnivaladwizard.com/home.asp">Learn More</a></p> </div> <div id="collateral" class="sub-box showhide"> <p>The Collateral Ordering Tool makes it easy for you to order destination brochures and the sales DVD for that upcoming event. <a href="http://carnival.litorders.com/workplace.asp">Learn More</a></p> </div> <div id="ebrochure" class="sub-box showhide"> <img src="../images/bookccl/img-ebrochure.gif" width="164" height="39" alt="Brochures" /> <p>Show your clients that you're listening to their specific vacation needs by delivering relevant planning info quickly. <a href="http://productiontrade.carnivalbrochures.com/start.aspx">Learn More</a></p> </div> <div id="brand" class="sub-box showhide"> <p>Carnival Brand Center is where you'll find information on our strategy, guidlines, templates and artwork. <a href="https://carnival.monigle2.net/user_info.asp?login_type=agent">Learn More</a></p> </div> <div id="funtees" class="sub-box showhide"> <img src="../images/bookccl/img-funtees.gif" width="164" height="39" alt="Funtees" /> <p>Create your very own Fun Design shirts to commemorate that special occasion aboard a Carnival "Fun Ship!" <a href="http://carnival.victorydyo.com/">Learn More</a></p> </div> </div><!-- ends .panel --> <a class="view" href="#">See All Marketing Tools</a> </div>

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• Drawing outlines around organic shapes

  - by ThunderChunky_SF

  One thing that seems particularly easy to do in the Flash IDE but difficult to do with code is to outline an organic shape. In the IDE you can just use the inkbucket tool to draw a stroke around something. Using nothing but code it seems much trickier. One method I've seen is to add a glow filter to the shape in question and just mess with the strength. But what if i want to only show the outline? What I'd like to do is to collect all of the points that make up the edge of the shape and then just connect the dots. I've actually gotten so far as to collect all of the points with a quick and dirty edge detection script that I wrote. So now I have a Vector of all the points that makeup my shape. How do I connect them in the proper sequence so it actually looks like the original object? For anyone who is interested here is my edge detection script: // Create a new sprite which we'll use for our outline var sp:Sprite = new Sprite(); var radius:int = 50; sp.graphics.beginFill(0x00FF00, 1); sp.graphics.drawCircle(0, 0, radius); sp.graphics.endFill(); sp.x = stage.stageWidth / 2; sp.y = stage.stageHeight / 2; // Create a bitmap data object to draw our vector data var bmd:BitmapData = new BitmapData(sp.width, sp.height, true, 0); // Use a transform matrix to translate the drawn clip so that none of its // pixels reside in negative space. The draw method will only draw starting // at 0,0 var mat:Matrix = new Matrix(1, 0, 0, 1, radius, radius); bmd.draw(sp, mat); // Pass the bitmap data to an actual bitmap var bmp:Bitmap = new Bitmap(bmd); // Add the bitmap to the stage addChild(bmp); // Grab all of the pixel data from the bitmap data object var pixels:Vector.<uint> = bmd.getVector(bmd.rect); // Setup a vector to hold our stroke points var points:Vector.<Point> = new Vector.<Point>; // Loop through all of the pixels of the bitmap data object and // create a point instance for each pixel location that isn't // transparent. var l:int = pixels.length; for(var i:int = 0; i < l; ++i) { // Check to see if the pixel is transparent if(pixels[i] != 0) { var pt:Point; // Check to see if the pixel is on the first or last // row. We'll grab everything from these rows to close the outline if(i <= bmp.width || i >= (bmp.width * bmp.height) - bmp.width) { pt = new Point(); pt.x = int(i % bmp.width); pt.y = int(i / bmp.width); points.push(pt); continue; } // Check to see if the current pixel is on either extreme edge if(int(i % bmp.width) == 0 || int(i % bmp.width) == bmp.width - 1) { pt = new Point(); pt.x = int(i % bmp.width); pt.y = int(i / bmp.width); points.push(pt); continue; } // Check to see if the previous or next pixel are transparent, // if so save the current one. if(i > 0 && i < bmp.width * bmp.height) { if(pixels[i - 1] == 0 || pixels[i + 1] == 0) { pt = new Point(); pt.x = int(i % bmp.width); pt.y = int(i / bmp.width); points.push(pt); } } } }

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• A very strange problem related to Flash and Java

  - by Nitesh Panchal

  Hello, I have created one simple program for showing webcam of the user. It works absolutely fine when i am running without integrating it in my java web application. But as soon as i copy paste the same files in Netbeans 6.8 and try to run it. My swf file is visible but the buttons in it are totally unclickable. I get the message of allow or deny showing webcam but the buttons are not clickable. It makes my application totally useless. I thought it's a minor issue but now it's getting on my nerves. I am trying it since 3 hours but didn't find any solution. I don't think anybody faced this issue till now that's why can't seem to find any thread in any forum on it in google. I am using Netbeans 6.8, Ubuntu, Glassfish V3 and JSF. Thanks in advance :). UPDATE:- It works fine on Windows XP. Then what can be the problem with Ubuntu? Any kind of permission rights that i need to give? 2nd UPDATE:- I think this is bug with Flash. I found that this code doesn't work :- <object classid="clsid:d27cdb6e-ae6d-11cf-96b8-444553540000" codebase="http://download.macromedia.com/pub/shockwave/cabs/flash/swflash.cab#version=9,0,0,0" id="VideoConferenceAdmin" align="middle"> <param name="allowScriptAccess" value="sameDomain" /> <param name="wmode" value="opaque"/> <param name="allowFullScreen" value="false" /> <param NAME="FlashVars" VALUE="rootIp=localhost&amp;userName=admin&amp;roomName=test" /> <param name="movie" value="Conference/VideoConference.swf" /><param name="quality" value="high" /> <embed src="Conference/VideoConference.swf" wmode="window" FlashVars="rootIp=localhost&amp;userName=test&amp;roomName=test" quality="high" width="600" height="500" name="VideoConference" align="middle" allowScriptAccess="sameDomain" allowFullScreen="false" type="application/x-shockwave-flash" pluginspage="http://www.macromedia.com/go/getflashplayer" /> </object> And this one works :- <object classid="clsid:d27cdb6e-ae6d-11cf-96b8-444553540000" codebase="http://download.macromedia.com/pub/shockwave/cabs/flash/swflash.cab#version=9,0,0,0" id="VideoConferenceAdmin" align="middle"> <param name="allowScriptAccess" value="sameDomain" /> <param name="wmode" value="opaque"/> <param name="allowFullScreen" value="false" /> <param NAME="FlashVars" VALUE="rootIp=localhost&amp;userName=admin&amp;roomName=test" /> <param name="movie" value="Conference/VideoConference.swf" /><param name="quality" value="high" /> <embed src="Conference/VideoConference.swf" wmode="window" FlashVars="rootIp=localhost&amp;userName=test&amp;roomName=test" quality="high" name="VideoConference" align="middle" allowScriptAccess="sameDomain" allowFullScreen="false" type="application/x-shockwave-flash" pluginspage="http://www.macromedia.com/go/getflashplayer" /> </object> As you can see, just by removing the height and width attribute the panels of Flash settings work fine. I know you will find me funny but i am not. You can check out on your own if you don't trust me. Now, my question would be, can anybody tell me how do i set height and width of swf? I want it to be 600px width and 500px height. Even the style attribute doesn't work. Can i set height and width from within Flash? because without explicitly setting height and width, it looks very small. I think this should be very easy for all now. Thanks in advance :)

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