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  • Want to add a functional language to my toolchest. Haskell or Erlang?

    - by sean.johnson
    I've been an OO/procedural guy my whole career except in school where I did a lot of logic programming (Prolog). I work on an amazing variety of projects (freelancer) and so I don't want the tools I know and understand to hold me back from using the right tool for the job. I've decided I should know a functional programming language. I've narrowed the field to Haskell and Erlang. What are the pros and cons, advantages and disadvantages, and major trade offs of Haskell and Erlang? How do I decide in a rational way, which is the better path? This is a big time investment, so I'd like to chose wisely. Is there a good case to be made for something else entirely? F#, Scala Ocaml? (BTW, I'm normally a Ruby/C/Obj.C guy, so I'm not terribly impressed or dependent on the JVM as a runtime. It's completely neutral to me. It's a fine runtime, I don't hold it for or against a language. I don't use Microsoft products though, so a .NET runtime would be a negative.)

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  • Convert asp.net application to windows forms app

    - by rogdawg
    I have written and deployed an ASP.NET application that is pretty complex. It uses XSL transformations to create web forms for a large variety of data objects. The data comes from the database as XML via a web service. Now, I need to create a Windows desktop application that will provide a small subset of the web applications functionality to a user who may not have access to the web (working in remote areas). I will provide the data syncing using the MS Sync Framework. And I will have the desktop use a local data store. I would like to use the same xslt files in the desktop app that I use in the web app for the form creation so that, if changes are made, the desktop app can update itself when it connects and syncs its data. But, I am wondering how to replicate the asp.net codebehind logic of my web app in the windows forms. If I use a browser control to render the XSLTransformation result, then how could I handle click events, etc, in the form? Also, can I launch other windows as "dialog boxes" from my windows forms (I do this in my web app using RadControls functionality)? Thanks for any advice you can give.

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  • Why is textbox.focus throwing the lostfocus event?

    - by cost
    I've seen a few similar questions on SO but nothing that seems to actually address the issue. Here's a simplified version of the function. Private Sub Check_Quantity(sender As System.Object, e As System.Windows.RoutedEventArgs) _ Handles textbox_quantity.LostFocus Dim worked As Boolean = Integer.TryParse(textbox_quantity.Text, quantity) If Not worked Then MsgBox("Enter a valid number for the quantity") textbox_quantity.Focus() textbox_quantity.SelectAll() quantity = 0 End If End Sub It's important to note that this is WPF. What I want to do is very simple. When someone finishes with the textbox the program checks that what they entered is a number. If it does it sticks this in an integer. If not, it tells them to fix it and keeps the focus on the textbox. The issue is a few things, but what it comes down to is this function runs in an infinite loop. This same function works fine in WinForms, but not in WPF. On some other questions people have said that the messagebox appearing causes focus to be lost, but in testing this isn't true. It still loops regardless of if the messagebox is called or not. The problem is the call to textbox_quantity.Focus(). Without that it works fine. Regardless of whether it's there or not though, focus is not set to the textbox, though textbox_quantity.Focus() still returns a value of true. Any thought of what's going on and maybe how I could fix it?

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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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  • Passing System classes as constructor parameters

    - by mcl
    This is probably crazy. I want to take the idea of Dependency Injection to extremes. I have isolated all System.IO-related behavior into a single class so that I can mock that class in my other classes and thereby relieve my larger suite of unit tests of the burden of worrying about the actual file system. But the File IO class I end up with can only be tested with integration tests, which-- of course-- introduces complexity I don't really want to deal with when all I really want to do is make sure my FileIO class calls the correct System.IO stuff. I don't need to integration test System.IO. My FileIO class is doing more than simply wrapping System.IO functions, every now and then it does contain some logic (maybe this is the problem?). So what I'd like is to be able to test my File IO class to ensure that it makes the correct system calls by mocking the System.IO classes themselves. Ideally this would be as easy as having a constructor like so: public FileIO( System.IO.Directory directory, System.IO.File file, System.IO.FileStream fileStream ) { this.Directory = directory; this.File = file; this.FileStream = fileStream; } And then calling in methods like: public GetFilesInFolder(string folderPath) { return this.Directory.GetFiles(folderPath) } But this doesn't fly since the System.IO classes in question are static classes. As far as I can tell they can neither be instantiated in this way or subclassed for the purposes of mocking.

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  • Is it possible to return a list of numbers from a Sybase function?

    - by ps_rs4
    I'm trying to overcome a very serious performance issue in which Sybase refuses to use the primary key index on a large table because one of the required fields is specified indirectly through another table - or, in other words; SELECT ... FROM BIGTABLE WHERE KFIELD = 123 runs in ms but SELECT ... FROM BIGTABLE, LTLTBL WHERE KFIELD = LTLTBL.LOOKUP AND LTLTBL.UNIQUEID = 'STRINGREPOF123' takes 30 - 40 seconds. I've managed to work around this first problem by using a function that basically lets me do this; SELECT ... FROM BIGTABLE WHERE KFIELD = MYFUNC('STRINGREPOF123') which also runs in ms. The problem, however, is that this approach only works when there is a single value returned by MYFUNCT but I have some cases where it may return 2 or 3 values. I know that the SQL SELECT ... FROM BIGTABLE WHERE KFIELD IN (123,456,789) also returns in millis so I'd like to have a function that returns a list of possible values rather than just a single one - is this possible? Sadly the application is running on Sybase ASA 9. Yes I know it is old and is scheduled to be refreshed but there's nothing I can do about it now so I need logic that will work with this version of the DB. Thanks in advance for any assistance on this matter.

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  • Help: List contents of iPhone application bundle subpath??

    - by bluepill
    Hi, I am trying to get a listing of the directories contained within a subpath of my application bundle. I've done some searching and this is what I have come up with - (void) contents { NSArray *contents = [[NSBundle mainBundle] pathsForResourcesOfType:nil inDirectory:@"DataDir"]; if (contents = nil) { NSLog(@"Failed: path doesn't exist or error!"); } else { NSString *bundlePathName = [[NSBundle mainBundle] bundlePath]; NSString *dataPathName = [bundlePathName stringByAppendingPathComponent: @"DataDir"]; NSFileManager *fileManager = [NSFileManager defaultManager]; NSMutableArray *directories = [[NSMutableArray alloc] init]; for (NSString *entityName in contents) { NSString *fullEntityName = [dataPathName stringByAppendingPathComponent:entityName]; NSLog(@"entity = %@", fullEntityName); BOOL isDir = NO; [fileManager fileExistsAtPath:fullEntityName isDirectory:(&isDir)]; if (isDir) { [directories addObject:fullEntityName]; NSLog(@" is a directory"); } else { NSLog(@" is not a directory"); } } NSLog(@"Directories = %@", directories); [directories release]; } } As you can see I am trying to get a listing of directories in the app bundle's DataDir subpath. The problem is that I get no strings in my contents NSArray. note: - I am using the simulator - When I manually look in the .app file I can see DataDir and the contents therein - The contents of DataDir are png files and directories that contain png files - The application logic needs to discover the contents of DataDir at runtime - I have also tried using NSArray *contents = [fileManager contentsOfDirectoryAtPath:DataDirPathName error:nil]; and I still get no entries in my contents array Any suggestions/alternative approaches? Thanks.

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  • problem linking vba modules in MS Access 2007

    - by Ted
    I am upgrading a database system from Access 2000 db to Access 2007, which communicates with several chemistry measuring devices(pH meter, scale, etc) via an RS 232 serial port. The first db consists of several modules containing vba code that enables the communications with the ports, as well as supports the code behind the forms in the second db. The user, or lab tech, navigates through the forms in the second db to interact with the lab devices, and also to generate the reports which display the info. from the devices. The reports are also part of the second db. The code works in Access 2000, but once I convert it to 2007, the code in the second db cannot find the function calls in the first db that dictate the progression from screen to screen. I have tried importing the modules into the second db, and I have tried linking them, but it still doesn't work. The error message is #438: "Object doesn't support this property or method." Any suggestions would be greatly appreciated. Here is the code for the first function that is not being called correctly: Description: ' This routine is used to return to the calling form and close the active form. ' ' Input: ' strFormCalled --- the active form ' strCallingForm --- the form that called the active form ' blnUnhideOrOpen --- whether to open or just unhide form Public Sub basReturnToCallingForm(ByVal strFormCalled As String, ByVal _ strCallingForm As Variant, Optional blnUnhideOrOpen As Boolean = True) On Error GoTo err_basReturnToCaliingForm If Not basIsBlankString(strCallingForm) And blnUnhideOrOpen Then DoCmd.OpenForm strCallingForm, acNormal Else Call basUnHideForm(strCallingForm) End If Call basCloseForm(strFormCalled) exit_basReturnToCaliingForm: Exit Sub err_basReturnToCaliingForm: Err.Raise Err.Number, "basReturnToCaliingForm", Err.Description End Sub I will post the second function shortly, but I have to go to a meeting... The second funtion that isn't 'working' is a cmdStartClick that is supposed to be called when a user initializes a pump. However, within that function, it's also sticking on a line that is supposed to progress to the next form in the db. The other thing is that the code works in Access 2002, but not in Access 2007...

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  • How do I "rebind" the click event after unbind('click') ?

    - by Ben
    I have an anchor tag <a class="next">next</a> made into a "button". Sometimes, this tag needs to be hidden if there is nothing new to show. All works fine if I simply hide the button with .hide() and re-display it with .show(). But I wanted to uses .fadeIn() and .fadeOut() instead. The problem I'm having is that if the user clicks on the button during the fadeOut animation, it can cause problems with the logic I have running the show. The solution I found was to unbind the click event from the button after the original click function begins, and then re-bind it after the animation is complete. $('a.next').click(function() { $(this).unbind('click'); ... // calls some functions, one of which fades out the a.next if needed ... $(this).bind('click'); } the last part of the above example does not work. The click event is not actually re-bound to the anchor. does anyone know the correct way to accomplish this? I'm a self-taught jquery guy, so some of the higher level things like unbind() and bind() are over my head, and the jquery documentation isn't really simple enough for me to understand.

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  • TreeView update bug in the VB.NET

    - by CFP
    Consider the following code: Dim Working As Boolean = False Private Sub TreeView1_AfterCheck(ByVal sender As Object, ByVal e As System.Windows.Forms.TreeViewEventArgs) Handles TreeView1.AfterCheck If Working Then Exit Sub Working = True e.Node.Checked = Not e.Node.Checked Working = False End Sub Private Sub TreeView1_MouseClick(ByVal sender As System.Object, ByVal e As System.Windows.Forms.MouseEventArgs) Handles TreeView1.MouseClick If e.Button = Windows.Forms.MouseButtons.Right Then MsgBox("Checked = " & TreeView1.SelectedNode.Checked) End Sub Where TreeView1 is a TreeView added to the form, with CheckBoxes set to true and one node added. The code basically cancel any node checking occuring on the form. Single-clicking the top node to check it works well : your click is immediately canceled. Yet if you double-click the checkbox, it will display a tick. But verifying the check state through a right click will yield a Checked = False dialog. How come? Is it a bug (I'm using the latest .Net Framework 4.0, and he same occurs in 2.0), or am I doing something wrong here? Is there a work around? Thanks! EDIT: Additionally, the MouseDoubleClick event is not raised before you click once again. EDIT 2: Posted a bug report at Microsoft Connect

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  • Ajax response takes time and status is 503

    - by Suresh S
    guys, i have a html page where onclick of a button a ajax request is sent to server , the request calls a jsp page which runs an oracle procedure.The procedure runs the logic and places it in a temp table . once procedure is completed , the values are returned to the client by selecting values from tmp table. as the response is too late . the data is not received at the client side. solution: i tried to run the procedure in a separate thread using a ajax call. when the procedure is completed a global flag is set to indicate that the data is generated. if the response is 500 , a second ajax call invoked by timeout function after 10000 ms . the second call checks the global flag ,if true then reads from table and sends the response. if not again a timeout is set at the client side. this solution is not mature enough. , as the procedure may take long time to respond. please let me know a good solution for this problenm?

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  • Compile C++ in Visual Studio

    - by Kasun
    Hi All.. I use this method to compile C++ file in VS. But even i provide the correct file it returns false. Can any one help me... This is class called CL class CL { private const string clexe = @"cl.exe"; private const string exe = "Test.exe", file = "test.cpp"; private string args; public CL(String[] args) { this.args = String.Join(" ", args); this.args += (args.Length > 0 ? " " : "") + "/Fe" + exe + " " + file; } public Boolean Compile(String content, ref string errors) { if (File.Exists(exe)) File.Delete(exe); if (File.Exists(file)) File.Delete(file); File.WriteAllText(file, content); Process proc = new Process(); proc.StartInfo.UseShellExecute = false; proc.StartInfo.RedirectStandardOutput = true; proc.StartInfo.RedirectStandardError = true; proc.StartInfo.FileName = clexe; proc.StartInfo.Arguments = this.args; proc.StartInfo.CreateNoWindow = true; proc.Start(); //errors += proc.StandardError.ReadToEnd(); errors += proc.StandardOutput.ReadToEnd(); proc.WaitForExit(); bool success = File.Exists(exe); return success; } } This is my button click event private void button1_Click(object sender, EventArgs e) { string content = "#include <stdio.h>\nmain(){\nprintf(\"Hello world\");\n}\n"; string errors = ""; CL k = new CL(new string[] { }); if (k.Compile(content, ref errors)) Console.WriteLine("Success!"); else MessageBox.Show("Errors are : ", errors); }

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  • File mkdirs() method not working in android/java

    - by Leif Andersen
    I've been pulling out my hair on this for a while now. The following method is supposed to download a file, and save it to the location specified on the hard drive. private static void saveImage(Context context, boolean backgroundUpdate, URL url, File file) { if (!Tools.checkNetworkState(context, backgroundUpdate)) return; // Get the image try { // Make the file file.getParentFile().mkdirs(); // Set up the connection URLConnection uCon = url.openConnection(); InputStream is = uCon.getInputStream(); BufferedInputStream bis = new BufferedInputStream(is); // Download the data ByteArrayBuffer baf = new ByteArrayBuffer(50); int current = 0; while ((current = bis.read()) != -1) { baf.append((byte) current); } // Write the bits to the file OutputStream os = new FileOutputStream(file); os.write(baf.toByteArray()); os.close(); } catch (Exception e) { // Any exception is probably a newtork faiilure, bail return; } } Also, if the file doesn't exist, it is supposed to make the directory for the file. (And if there is another file already in that spot, it should just not do anything). However, for some reason, the mkdirs() method never makes the directory. I've tried everything from explicit parentheses, to explicitly making the parent file class, and nothing seems to work. I'm fairly certain that the drive is writable, as it's only called after that has already been determined, also that is true after running through it while debugging. So the method fails because the parent directories aren't made. Can anyone tell me if there is anything wrong with the way I'm calling it? Also, if it helps, here is the source for the file I'm calling it in: https://github.com/LeifAndersen/NetCatch/blob/master/src/net/leifandersen/mobile/android/netcatch/services/RSSService.java Thank you

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  • Calling a network State check from other activities

    - by Laurent
    I realize this question has been answered before but couldn't find an answer that deals with my specific case. I want to create a class called "InternetConnectionChecks" that will handle checking a network state and http timeouts. I'll call the methods twice in the app (once at the beginning to get data from a server, and once at the end to send user orders to the server). For good form I'd like to put all these methods in a single class rather than copy/paste at different points in my code. To check the network state, I'm using ConnectivityManager; thing is, getSystemService requires a class that extends Activity. package arbuckle.app; import android.app.Activity; import android.app.Service; import android.content.Context; import android.net.ConnectivityManager; import android.net.NetworkInfo; public class InternetConnectionChecks extends Activity { public boolean isNetworkAvailable(){ ConnectivityManager connectivityManager = (ConnectivityManager) getSystemService(Context.CONNECTIVITY_SERVICE); NetworkInfo activeNetworkInfo = connectivityManager.getActiveNetworkInfo(); if ((activeNetworkInfo != null)&&(activeNetworkInfo.isConnected())){ return true; }else{ return false; } } } QUESTION: if I call the method isNetworkAvailable from another activity, am I: - going to hit up serious errors. - violating good coding form? *If this isn't the right way to do things, can you point me in the right direction to set up a separate class I can call on to check internet connection? Thanks everyone!

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  • Adding a Way To preserve A Comma In A CSV To DataTable Function

    - by Nick LaMarca
    I have a function that converts a .csv file to a datatable. One of the columns I am converting is is a field of names that have a comma in them i.e. "Doe, John" when converting the function treats this as 2 seperate fields because of the comma. I need the datatable to hold this as one field Doe, John in the datatable. Function CSV2DataTable(ByVal filename As String, ByVal sepChar As String) As DataTable Dim reader As System.IO.StreamReader Dim table As New DataTable Dim colAdded As Boolean = False Try ''# open a reader for the input file, and read line by line reader = New System.IO.StreamReader(filename) Do While reader.Peek() >= 0 ''# read a line and split it into tokens, divided by the specified ''# separators Dim tokens As String() = System.Text.RegularExpressions.Regex.Split _ (reader.ReadLine(), sepChar) ''# add the columns if this is the first line If Not colAdded Then For Each token As String In tokens table.Columns.Add(token) Next colAdded = True Else ''# create a new empty row Dim row As DataRow = table.NewRow() ''# fill the new row with the token extracted from the current ''# line For i As Integer = 0 To table.Columns.Count - 1 row(i) = tokens(i) Next ''# add the row to the DataTable table.Rows.Add(row) End If Loop Return table Finally If Not reader Is Nothing Then reader.Close() End Try End Function

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  • Speed comparison - Template specialization vs. Virtual Function vs. If-Statement

    - by Person
    Just to get it out of the way... Premature optimization is the root of all evil Make use of OOP etc. I understand. Just looking for some advice regarding the speed of certain operations that I can store in my grey matter for future reference. Say you have an Animation class. An animation can be looped (plays over and over) or not looped (plays once), it may have unique frame times or not, etc. Let's say there are 3 of these "either or" attributes. Note that any method of the Animation class will at most check for one of these (i.e. this isn't a case of a giant branch of if-elseif). Here are some options. 1) Give it boolean members for the attributes given above, and use an if statement to check against them when playing the animation to perform the appropriate action. Problem: Conditional checked every single time the animation is played. 2) Make a base animation class, and derive other animations classes such as LoopedAnimation and AnimationUniqueFrames, etc. Problem: Vtable check upon every call to play the animation given that you have something like a vector<Animation>. Also, making a separate class for all of the possible combinations seems code bloaty. 3) Use template specialization, and specialize those functions that depend on those attributes. Like template<bool looped, bool uniqueFrameTimes> class Animation. Problem: The problem with this is that you couldn't just have a vector<Animation> for something's animations. Could also be bloaty. I'm wondering what kind of speed each of these options offer? I'm particularly interested in the 1st and 2nd option because the 3rd doesn't allow one to iterate through a general container of Animations. In short, what is faster - a vtable fetch or a conditional?

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  • highlight listview items android

    - by user1752939
    I have listview with custom base adapter. When I populate the list I have to check a boolean in the object I'm populating the listview and if it is true to change the background color of that row. public View getView(int position, View convertView, ViewGroup parent) { LoginsList entry = listOfLoginsLists.get(position); if (convertView == null) { LayoutInflater inflater = (LayoutInflater) context.getSystemService(Context.LAYOUT_INFLATER_SERVICE); convertView = inflater.inflate(R.layout.lists_row, null); } TextView ListName = (TextView) convertView.findViewById(R.id.tvListName); ListName.setText(entry.getListName()); TextView ListDescription = (TextView) convertView.findViewById(R.id.tvListDescription); ListDescription.setText(entry.getListDescription()); Button Send = (Button) convertView.findViewById(R.id.bSend); Send.setOnClickListener(this); Send.setTag(entry); RelativeLayout RelLayout = (RelativeLayout) convertView.findViewById(R.id.layoutListsRow); RelLayout.setFocusableInTouchMode(false); RelLayout.setFocusable(false); RelLayout.setOnClickListener(this); RelLayout.setTag(entry); if (entry.isSent()) { RelLayout.setBackgroundColor(Color.parseColor("#4400FF00")); } return convertView; } But this code doesn't work right. When I scroll the list view the rows colors get messed up.

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  • [Rails] checkbox to update attribute

    - by Jeff
    [Updated a bit] I have a Task model that has a :completed boolean attribute. If I click on it I want it to execute the 'finish' method. The main problem is that I am displays a series of checkboxes in a list and subsequent checkboxes after the first one are ignored. The method is never called for the given task/checkbox combo. I have this chunk of code in my view: <% current_user.tasks.each do |t|%> <% if t.completed == false %> <%= check_box_tag :completed, true, checked = false %> <%= observe_field :completed, :url => { :controller => 'tasks', :action => :finish , :id => t.id }, :frequency => 0.25, :update => :completed, :with => true %> and my finish method looks like this: def finish @task = Task.find(params[:id]) new = {:completed => true} @task.update_attributes(new) render :update do |page| page.replace_html "taskListing", :partial => 'home/task_listing' end

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  • What is a mantainable way of saving "star rating" in a database?

    - by Montecristo
    I'll use the jQuery plugin for presenting the user with a nice interface The request is to display 5 stars, up to a total score of 10 (2 points per star). By now I thought about using 7/10 as a format for that value, but what if at some point in the future I'll receive a request like We would like to give users more choice, let's increase the total score to 20 (so that each star contributes with a maximum of 4 points) I'll end up with a table with mixed values for the "star rating" column: some will be like 7/10 while others will be like 14/20. Is it ok for you to have this difference in the database and deal with it in the logic layer to have it consistent? Or is preferred another way so that querying the table will not result in inconsistent results outside the application? Maybe floating point values could help me, is it better to store that value as a number less than or equal to one? So in each of the two examples the resulting value stored in the database would be 0,7, as a number, not a varchar, which can be queried also outside the application. What do you think?

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  • Advice on Minimizing Stored Procedure Parameters

    - by RPM1984
    Hi Guys, I have an ASP.NET MVC Web Application that interacts with a SQL Server 2008 database via Entity Framework 4.0. On a particular page, i call a stored procedure in order to pull back some results based on selections on the UI. Now, the UI has around 20 different input selections, ranging from a textbox, dropdown list, checkboxes, etc. Each of those inputs are "grouped" into logical sections. Example: Search box : "Foo" Checkbox A1: ticked, Checkbox A2: unticked Dropdown A: option 3 selected Checkbox B1: ticked, Checkbox B2: ticked, Checkbox B3: unticked So i need to call the SPROC like this: exec SearchPage_FindResults @SearchQuery = 'Foo', @IncludeA1 = 1, @IncludeA2 = 0, @DropDownSelection = 3, @IncludeB1 = 1, @IncludeB2 = 1, @IncludeB3 = 0 The UI is not too important to this question - just wanted to give some perspective. Essentially, i'm pulling back results for a search query, filtering these results based on a bunch of (optional) selections a user can filter on. Now, My questions/queries: What's the best way to pass these parameters to the stored procedure? Are there any tricks/new ways (e.g SQL Server 2008) to do this? Special "table" parameters/arrays - can we pass through User-Defined-Types? Keep in mind im using Entity Framework 4.0 - but could always use classic ADO.NET for this if required. What about XML? What are the serialization/de-serialization costs here? Is it worth it? How about a parameter for each logical section? Comma-seperated perhaps? Just thinking out loud. This page is particulary important from a user point of view, and needs to perform really well. The stored procedure is already heavy in logic, so i want to minimize the performance implications - so keep that in mind. With that said - what is the best approach here?

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  • Java's Swing Threading

    - by nevets1219
    My understanding is that if I start up another thread to perform some actions, I would need to SwingUtilities.invokeAndWait or SwingUtilities.invokeLater to update the GUI while I'm in said thread. Please correct me if I'm wrong. What I'm trying to accomplish is relatively straightforward: when the user clicks submit, I want to (before performing any actions) disable the submit button, perform the action, and at the end of the action re-enable the button. My method to perform the action updates the GUI directly (displays results) when it gets the results back. This action basically queries a server and gets some results back. What I have so far is: boolean isRunning = false; synchronized handleButtonClick() { if ( isRunning == false ) { button.setEnabled( false ); isRunning = true; doAction(); } } doAction() { new Thread() { try { doAction(); // Concern A } catch ( ... ) { displayStackTrace( ... ); // Concern B } finally { SwingUtilities.invokeLater ( /* simple Runnable to enable button */ ); isRunning = false; } } } For both of my concerns above, do I would have to use SwingUtilities.invokeAndWait since they both will update the GUI? All GUI updates revolve around updating JTextPane. Do I need to in my thread check if I'm on EDT and if so I can call my code (regardless of whether it updates the GUI or not) and NOT use SwingUtilities.invokeAndWait?

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  • How to "upgrade" the database in real world?

    - by Tattat
    My company have develop a web application using php + mysql. The system can display a product's original price and discount price to the user. If you haven't logined, you get the original price, if you loginned , you get the discount price. It is pretty easy to understand. But my company want more features in the system, it want to display different prices base on different user. For example, user A is a golden parnter, he can get 50% off. User B is a silver parnter, only have 30 % off. But this logic is not prepare in the original system, so I need to add some attribute in the database, at least a user type in this example. Is there any recommendation on how to merge current database to my new version of database. Also, all the data should preserver, and the server should works 24/7. (within stop the database) Is it possible to do so? Also , any recommend for future maintaince advice? Thz u.

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  • Save as Ringtone from ContextMenu

    - by kostas_menu
    I have created a button that onClick plays a mp3 file.I have also create a context menu that when you press the button for 2 secs it prompts you to save it as ringtone.How can i save it somewhere in my sd?this is my code: public void onCreate(Bundle icicle) { super.onCreate(icicle); setContentView(R.layout.main); Toast.makeText(a.this, "Touch and listen", Toast.LENGTH_SHORT).show(); Button button = (Button) findViewById(R.id.btn1); registerForContextMenu(button); button.setOnClickListener(new View.OnClickListener() { public void onClick(View v){ MediaPlayer mp = MediaPlayer.create(a.this, R.raw.myalo); mp.start(); Toast.makeText(a.this, "Eisai sto myalo", Toast.LENGTH_SHORT).show(); } }); @Override public void onCreateContextMenu(ContextMenu menu, View v,ContextMenuInfo menuInfo) { super.onCreateContextMenu(menu, v, menuInfo); menu.setHeaderTitle("Save As:"); menu.add(0, v.getId(), 0, "Ringtone"); } @Override public boolean onContextItemSelected(MenuItem item) { if(item.getTitle()=="Ringtone"){function1(item.getItemId());} else {return false;} return true; } public void function1(int id){ Toast.makeText(this, "Ringtone Saved", Toast.LENGTH_SHORT).show(); } }

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  • Any guidelines for handling the Headset and Bluetooth AVRC transport controls in Android 2.2

    - by StefanK
    I am trying to figure out what is the correct (new) approach for handling the Intent.ACTION_MEDIA_BUTTON in Froyo. In pre 2.2 days we had to register a BroadcastReceiver (either permanently or at run-time) and the Media Button events would arrive, as long as no other application intercepts them and aborts the broadcast. Froyo seems to still somewhat support that model (at least for the wired headset), but it also introduces the registerMediaButtonEventReceiver, and unregisterMediaButtonEventReceiver methods that seem to control the "transport focus" between applications. During my experiments, using registerMediaButtonEventReceiver does cause both the bluetooth and the wired headset button presses to be routed to the application's broadcast receiver (the app gets the "transport focus"), but it looks like any change in the audio routing (for example unplugging the headset) shits the focus back to the default media player. What is the logic behind the implementation in Android 2.2? What is correct way to handle transport controls? Do we have to detect the change in the audio routing and try to re-gain the focus? This is an issue that any 3rd party media player on the Android platform has to deal with, so I hope that somebody (probably a Google Engineer) can provide some guidelines that we can all follow. Having a standard approach may make headset button controls a bit more predictable for the end users. Stefan

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  • SELECT product from subclass: How many queries do I need?

    - by Stefano
    I am building a database similar to the one described here where I have products of different type, each type with its own attributes. I report a short version for convenience product_type ============ product_type_id INT product_type_name VARCHAR product ======= product_id INT product_name VARCHAR product_type_id INT -> Foreign key to product_type.product_type_id ... (common attributes to all product) magazine ======== magazine_id INT title VARCHAR product_id INT -> Foreign key to product.product_id ... (magazine-specific attributes) web_site ======== web_site_id INT name VARCHAR product_id INT -> Foreign key to product.product_id ... (web-site specific attributes) This way I do not need to make a huge table with a column for each attribute of different product types (most of which will then be NULL) How do I SELECT a product by product.product_id and see all its attributes? Do I have to make a query first to know what type of product I am dealing with and then, through some logic, make another query to JOIN the right tables? Or is there a way to join everything together? (if, when I retrieve the information about a product_id there are a lot of NULL, it would be fine at this point). Thank you

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