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  • Scheduling Swingworker threads

    - by Simonw
    Hi, I have a 2 processes to perform in my swing application, one to fill a list, and one to do operations on each element on the list. I've just moved the 2 processes into Swingworker threads to stop the GUI locking up while the tasks are performed, and because I will need to do this set of operations to several lists, so concurrency wouldn't be a bad idea in the first place. However, when I just ran fillList.execute();doStuffToList.execute(); the doStuffToList thread to ran on the empty list (duh...). How do I tell the second process to wait until the first one is done? I suppose I could just nest the second process at the end of the first one, but i dunno, it seems like bad practice.

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  • How to investigate if opencl is possible for an algorithm

    - by Marnix
    I have a heavy-duty algorithm in C# that takes two large Bitmaps of about 10000x5000 and performs photo and ray collision operations on a 3D model to map photos on the 3D model. I would like to know if it is possible to convert such an algorithm to OpenCL to optimize parallel operations during the algorithm. But before asking you to go into the details of the algorithm, I would like to know how I can investigate if my algorithm is convertible to OpenCL. I am not experienced in OpenCL and I would like to know if it is worth it to get into it and learn how it works. Are there things I have to look for that will definitely not work on the graphics card? (for-loops, recursion) Update: My algorithm goes something like: foreach photo split the photo in 64x64 blocks foreach block cast a ray from the camera to the 3D model foreach triangle in 3D model perform raycheck

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  • Implementing EAV pattern with Hibernate for User -> Settings relationship

    - by Trevor
    I'm trying to setup a simple EAV pattern in my web app using Java/Spring MVC and Hibernate. I can't seem to figure out the magic behind the hibernate XML setup for this scenario. My database table "SETUP" has three columns: user_id (FK) setup_item setup_value The database composite key is made up of user_id | setup_item Here's the Setup.java class: public class Setup implements CommonFormElements, Serializable { private Map data = new HashMap(); private String saveAction; private Integer speciesNamingList; private User user; Logger log = LoggerFactory.getLogger(Setup.class); public String getSaveAction() { return saveAction; } public void setSaveAction(String action) { this.saveAction = action; } public User getUser() { return user; } public void setUser(User user) { this.user = user; } public Integer getSpeciesNamingList() { return speciesNamingList; } public void setSpeciesNamingList(Integer speciesNamingList) { this.speciesNamingList = speciesNamingList; } public Map getData() { return data; } public void setData(Map data) { this.data = data; } } My problem with the Hibernate setup, is that I can't seem to figure out how to map out the fact that a foreign key and the key of a map will construct the composite key of the table... this is due to a lack of experience using Hibernate. Here's my initial attempt at getting this to work: <composite-id> <key-many-to-one foreign-key="id" name="user" column="user_id" class="Business.User"> <meta attribute="use-in-equals">true</meta> </key-many-to-one> </composite-id> <map lazy="false" name="data" table="setup"> <key column="user_id" property-ref="user"/> <composite-map-key class="Command.Setup"> <key-property name="data" column="setup_item" type="string"/> </composite-map-key> <element column="setup_value" not-null="true" type="string"/> </map> Any insight into how to properly map this common scenario would be most appreciated!

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  • Is this asking too much of a browser?

    - by Matt Ball
    I'm embedding a large array in <script> tags in my HTML, like this (nothing surprising): <script> var largeArray = [/* lots of stuff in here */]; </script> In this particular example, the array has 210,000 elements. That's well below the theoretical maximum of 231 - by 4 orders of magnitude. Here's the fun part: if I save JS source for the array to a file, that file is 44 megabytes (46,573,399 bytes, to be exact). If you want to see for yourself, you can download it from my Dropbox. (All the data in there is canned, so much of it is repeated. This will not be the case in production.) Now, I'm really not concerned about serving that much data. My server gzips its responses, so it really doesn't take all that long to get the data over the wire. However, there is a really nasty tendency for the page, once loaded, to crash the browser. I'm not testing at all in IE (this is an internal tool). My primary targets are Chrome 8 and Firefox 3.6. In Firefox, I can see a reasonably useful error in the console: Error: script stack space quota is exhausted In Chrome, I simply get the sad-tab page: Cut to the chase, already Is this really too much data for our modern, "high-performance" browsers to handle? Is there anything I can do* to gracefully handle this much data? Incidentally, I was able to get this to work (read: not crash the tab) on-and-off in Chrome. I really thought that Chrome, at least, was made of tougher stuff, but apparently I was wrong... Edit 1 @Crayon: I wasn't looking to justify why I'd like to dump this much data into the browser at once. Short version: either I solve this one (admittedly not-that-easy) problem, or I have to solve a whole slew of other problems. I'm opting for the simpler approach for now. @various: right now, I'm not especially looking for ways to actually reduce the number of elements in the array. I know I could implement Ajax paging or what-have-you, but that introduces its own set of problems for me in other regards. @Phrogz: each element looks something like this: {dateTime:new Date(1296176400000), terminalId:'terminal999', 'General___BuildVersion':'10.05a_V110119_Beta', 'SSM___ExtId':26680, 'MD_CDMA_NETLOADER_NO_BCAST___Valid':'false', 'MD_CDMA_NETLOADER_NO_BCAST___PngAttempt':0} @Will: but I have a computer with a 4-core processor, 6 gigabytes of RAM, over half a terabyte of disk space ...and I'm not even asking for the browser to do this quickly - I'm just asking for it to work at all! ? *other than the obvious: sending less data to the browser

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  • Rails + AMcharts (with export image php script) - PHP script converted to controller?

    - by Elliot
    Hey Guys, This one might be a little confusing. I'm using AMCharts with rails. Amcharts comes with a PHP script to export images called "export.php" I'm trying to figure out how to take the code in export.php and put it into a controller. Here is the code: <?php // amcharts.com export to image utility // set image type (gif/png/jpeg) $imgtype = 'jpeg'; // set image quality (from 0 to 100, not applicable to gif) $imgquality = 100; // get data from $_POST or $_GET ? $data = &$_POST; // get image dimensions $width = (int) $data['width']; $height = (int) $data['height']; // create image object $img = imagecreatetruecolor($width, $height); // populate image with pixels for ($y = 0; $y < $height; $y++) { // innitialize $x = 0; // get row data $row = explode(',', $data['r'.$y]); // place row pixels $cnt = sizeof($row); for ($r = 0; $r < $cnt; $r++) { // get pixel(s) data $pixel = explode(':', $row[$r]); // get color $pixel[0] = str_pad($pixel[0], 6, '0', STR_PAD_LEFT); $cr = hexdec(substr($pixel[0], 0, 2)); $cg = hexdec(substr($pixel[0], 2, 2)); $cb = hexdec(substr($pixel[0], 4, 2)); // allocate color $color = imagecolorallocate($img, $cr, $cg, $cb); // place repeating pixels $repeat = isset($pixel[1]) ? (int) $pixel[1] : 1; for ($c = 0; $c < $repeat; $c++) { // place pixel imagesetpixel($img, $x, $y, $color); // iterate column $x++; } } } // set proper content type header('Content-type: image/'.$imgtype); header('Content-Disposition: attachment; filename="chart.'.$imgtype.'"'); // stream image $function = 'image'.$imgtype; if ($imgtype == 'gif') { $function($img); } else { $function($img, null, $imgquality); } // destroy imagedestroy($img); ?>

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  • What'd be a good pattern on Doctrine to have multiple languages

    - by PERR0_HUNTER
    Hi! I have this challenge which consist in having a system that offers it's content in multiple languages, however a part of the data contained in the system is not translatable such as dates, ints and such. I mean if I have a content on the following YAML Corporativos: columns: nombre: type: string(254) notnull: true telefonos: type: string(500) email: type: string(254) webpage: type: string(254) CorporativosLang: columns: corporativo_id: type: integer(8) notnull: true lang: type: string(16) fixed: false ubicacion: type: string() fixed: false unsigned: false primary: false notnull: true autoincrement: false contacto: type: string() fixed: false unsigned: false primary: false notnull: true autoincrement: false tipo_de_hoteles: type: string(254) fixed: false unsigned: false primary: false notnull: true autoincrement: false paises: type: string() fixed: false unsigned: false primary: false notnull: true autoincrement: false relations: Corporativo: class: Corporativos local: corporativo_id foreign: id type: one foreignAlias: Data This would allow me to have different corporative offices, however the place of the corp, the contact and other things can be translate into a different language (lang) Now this code here would create me a brand new corporative office with 2 translations $corporativo = new Corporativos(); $corporativo->nombre = 'Duck Corp'; $corporativo->telefonos = '66303713333'; $corporativo->email = '[email protected]'; $corporativo->webpage = 'http://quack.com'; $corporativo->Data[0]->lang = 'en'; $corporativo->Data[0]->ubicacion = 'zomg'; $corporativo->Data[1]->lang = 'es'; $corporativo->Data[1]->ubicacion = 'zomg amigou'; the thing now is I don't know how to retrieve this data in a more friendly way, because if I'd like to access my Corporative info in english I'd had to run DQL for the corp and then another DQL for the specific translation in english, What I'd love to do is have my translatable fields available in the root so I could simply access them $corporativo = new Corporativos(); $corporativo->nombre = 'Duck Corp'; $corporativo->telefonos = '66303713333'; $corporativo->email = '[email protected]'; $corporativo->webpage = 'http://quack.com'; $corporativo->lang = 'en'; $corporativo->ubicacion = 'zomg'; this way the translatable fields would be mapped to the second table automatically. I hope I can explain my self clear :( any suggestions ?

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  • problem with two .NET threads and hardware access

    - by mack369
    I'm creating an application which communicates with the device via FT2232H USB/RS232 converter. For communication I'm using FTD2XX_NET.dll library from FTDI website. I'm using two threads: first thread continuously reads data from the device the second thread is the main thread of the Windows Form Application I've got a problem when I'm trying to write any data to the device while the receiver's thread is running. The main thread simply hangs up on ftdiDevice.Write function. I tried to synchronize both threads so that only one thread can use Read/Write function at the same time, but it didn't help. Below code responsible for the communication. Note that following functions are methods of FtdiPort class. Receiver's thread private void receiverLoop() { if (this.DataReceivedHandler == null) { throw new BackendException("dataReceived delegate is not set"); } FTDI.FT_STATUS ftStatus = FTDI.FT_STATUS.FT_OK; byte[] readBytes = new byte[this.ReadBufferSize]; while (true) { lock (FtdiPort.threadLocker) { UInt32 numBytesRead = 0; ftStatus = ftdiDevice.Read(readBytes, this.ReadBufferSize, ref numBytesRead); if (ftStatus == FTDI.FT_STATUS.FT_OK) { this.DataReceivedHandler(readBytes, numBytesRead); } else { Trace.WriteLine(String.Format("Couldn't read data from ftdi: status {0}", ftStatus)); Thread.Sleep(10); } } Thread.Sleep(this.RXThreadDelay); } } Write function called from main thread public void Write(byte[] data, int length) { if (this.IsOpened) { uint i = 0; lock (FtdiPort.threadLocker) { this.ftdiDevice.Write(data, length, ref i); } Thread.Sleep(1); if (i != (int)length) { throw new BackendException("Couldnt send all data"); } } else { throw new BackendException("Port is closed"); } } Object used to synchronize two threads static Object threadLocker = new Object(); Method that starts the receiver's thread private void startReceiver() { if (this.DataReceivedHandler == null) { return; } if (this.IsOpened == false) { throw new BackendException("Trying to start listening for raw data while disconnected"); } this.receiverThread = new Thread(this.receiverLoop); //this.receiverThread.Name = "protocolListener"; this.receiverThread.IsBackground = true; this.receiverThread.Start(); } The ftdiDevice.Write function doesn't hang up if I comment following line: ftStatus = ftdiDevice.Read(readBytes, this.ReadBufferSize, ref numBytesRead);

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  • Implement Semi-Round-Robin file which can be expanded and saved on demand

    - by ircmaxell
    Ok, that title is going to be a little bit confusing. Let me try to explain it a little bit better. I am building a logging program. The program will have 3 main states: Write to a round-robin buffer file, keeping only the last 10 minutes of data. Write to a buffer file, ignoring the time (record all data). Rename entire buffer file, and start a new one with the past 10 minutes of data (and change state to 1). Now, the use case is this. I have been experiencing some network bottlenecks from time to time in our network. So I want to build a system to record TCP traffic when it detects the bottleneck (detection via Nagios). However by the time it detects the bottlenecking, most of the useful data has already been transmitted. So, what I'd like is to have a deamon that runs something like dumpcap all the time. In normal mode, it'll only keep the past 10 minutes of data (Since there's no point in keeping a boat load of data if it's not needed). But when Nagios alerts, I will send a signal in the deamon to store everything. Then, when Naigos recovers it will send another signal to stop storing and flush the buffer to a save file. Now, the problem is that I can't see how to cleanly store a rotating 10 minutes of data. I could store a new file every 10 minutes and delete the old ones if in mode 1. But that seems a bit dirty to me (especially when it comes to figuring out when the alert happened in the file). Ideally, the file that was saved should be such that the alert is always at the 10:00 mark in the file. While that is possible with new files every 10 minutes, it seems like a bit dirty to "repair" the files to that point. Any ideas? Should I just do a rotating file system and combine them into 1 at the end (doing quite a bit of post-processing)? Is there a way to implement the semi-round-robin file cleanly so that there is no need for any post-processing? Thanks Oh, and the language doesn't matter as much at this stage (I'm leaning towards Python, but have no objection to any other language. It's less of an issue than the overall design)...

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  • Sql Server Compact 2005 on Visual Studio 2008

    - by Tim
    I'm working on a Windows Forms application that interacts with a Sql Compact database file created by SQL Server 2005. This application was originally developed in Visual Studio 2005 but was recently converted to a Visual Studio 2008 solution. In regards to Sql Compact, we made sure the references were all still set to the assemblies that handle the 2005 version of Sql Compact rather than Sql Compact 3.5. Having done this, the application still runs just as it should - it will still interact with the Compact database, perform synchronization operations, etc. However, I just discovered today that Visual Studio tools such as the DataSet Designer do not play well with a Sql Compact database file of an older version than 3.5. If I go to the New Connection... wizard, the only Sql Compact Data Source / Data Provider are for Sql Compact 3.5. I assume that Visual Studio 2008 just doesn't include the data provider for the older version of Sql Compact by default. Is there a way you can add the old version of Sql Compact to the list of "Data Sources" for the connection wizard? To see exactly what I'm referring to, click on the Tools menu of Visual Studio 2008 and click Connect to Database... In the window that comes up, click Change... next to the Data source setting. From this dialog there is no way I can select the earlier version of Sql Compact - only 3.5 is available. Maybe I need to add an assembly reference somewhere? Or copy some file(s) from my Visual Studio 2005 directory over to 2008? I would think there would have to be a way for Visual Studio 2008 to be able to interact with a Sql Compact database from Sql Server 2005. To provide one more bit of detail, I discovered this problem when I went to my DataSet, right-clicked and tried to add a TableAdapter. The first screen that comes up says, "Choose Your Data Connection". If I leave it set to the Sql Compact connection that we've always used, I now get the following error when clicking the Next button: Failed to open a connection to the database "The selected database was created with an earlier version of SQL Server Compact and needs to be upgraded to SQL Server Compact 3.5 before the connection can be opened or tested. Upgrade the database by creating a new data connection and completing the Add Connection dialog box." Check the connection and try again. The only problem here is that we still use Sql Server 2005, and if my understanding is correct, it does not produce subscription files that are compatible with Sql Compact 3.5. If I am wrong in this assumption, please correct me. Any help you can provide is greatly appreciated. Thank you.

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  • Most optimized way to calculate modulus in C

    - by hasanatkazmi
    I have minimize cost of calculating modulus in C. say I have a number x and n is the number which will divide x when n == 65536 (which happens to be 2^16): mod = x % n (11 assembly instructions as produced by GCC) or mod = x & 0xffff which is equal to mod = x & 65535 (4 assembly instructions) so, GCC doesn't optimize it to this extent. In my case n is not x^(int) but is largest prime less than 2^16 which is 65521 as I showed for n == 2^16, bit-wise operations can optimize the computation. What bit-wise operations can I preform when n == 65521 to calculate modulus.

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  • JQGrid and JQuery Autocomplete

    - by Neff
    When implementing JQGrid 4.3.0, Jquery 1.6.2, and JQuery UI 1.8.16 Ive come across an issue with the Inline edit. When the inline edit is activated, some of the elements get assigned an auto complete. When the inline edit is canceld or saved, the auto complete does not always go away (selecting text by double clicking it then hitting delete, then hitting escape to exit row edit). Leaving the auto complete controls in edit mode when the row is no longer considered in edit mode. Perhaps you can tell me if there is a problem with the initialization or if I you are aware of an event post-"afterrestorefunc" that the fields can be returned to their "original" state. Original state being displayed as data in the JQGrid row. I've tried removing the DOM after row close, .remove() and .empty(): ... "afterrestorefunc": function(){ $('.ui-autocomplete-input').remove(); } ... but that causes other issues, such as the jqgrid is not able to find the cell when serializing the row for data or edit, and requires a refresh of the page, not just jqgrid, to be able to once again see the data from that row. Auto complete functionality for the element is created on the double click of the row: function CreateCustomSearchElement(value, options, selectiontype) { ... var el; el = document.createElement("input"); ... $(el).autocomplete({ source: function (request, response) { $.ajax({ url: '<%=ResolveUrl("~/Services/AutoCompleteService.asmx/GetAutoCompleteResponse") %>', data: "{ 'prefixText': '" + request.term + "', 'contextKey': '" + options.name + "'}", dataType: "json", type: "POST", contentType: "application/json; charset=utf-8", success: function (data) { response($.map(data.d, function (item) { return { label: Trim(item), value: Trim(item), searchVal: Trim(item) } })) } }); }, select: function (e, item) { //Select is on the event of selection where the value and label have already been determined. }, minLength: 1, change: function (event, ui) { //if the active element was not the search button //... } }).keyup(function (e) { if (e.keyCode == 8 || e.keyCode == 46) { //If the user hits backspace or delete, check the value of the textbox before setting the searchValue //... } }).keydown(function (e) { //if keycode is enter key and there is a value, you need to validate the data through select or change(onblur) if (e.keyCode == '13' && ($(el).val())) { return false; } if (e.keyCode == '220') { return false } }); } Other Sources: http://www.trirand.com/jqgridwiki/doku.php?id=wiki:inline_editing http://api.jqueryui.com/autocomplete/ Update: I tried only creating the autocomplete when the element was focused, and removing it when onblur. That did not resolve the issue either. It seems to just need the autocomplete dropdown to be triggered.

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  • Asp.NET custom templated datalist throws argument out of range (index) on button press

    - by MrTortoise
    I have a class BaseTemplate public abstract class BaseTemplate : ITemplate This adds the controls, and provides abstract methods to implement in the inheriting class. The inheriting class then adds its html according to its data source and manages the data binding. This all works fine - I get the control appearing with properly parsed html. The problem is that the base class adds controls into the template that have their own CommandName arguments; the idea is that the class that implements the custom templated dataList will provide the logic of setting the Selected and Edit Indexes. This class also manages the data binding, etc. It sets all of the templates on the datalist in the Init method (which was another cause of this exception). The exception gets thrown when I hit one of these buttons - I have tried hooking up both their click and command events everywhere in case this was the problem. I have also ensured that their command names do not match any of the system ones. The stack trace does not include any references to my methods or objects which is why I am so stuck. It is the most unhelpful message I can imagine. The really frustrating thing is that I cannot get a breakpoint to fire - i.e. the problem is happening after I click the button, but before and of my code can execute. The last time this exception happened was when I had this code in a user control and was assigning the templates to the datalist in the PageLoad. I moved these into init to fix that problem; however, this is a problem that was there then and I have no idea what is causing it let alone how to solve it (and index out of range doesn't really help without knowing what index.) The Exception Details Exception Details: System.ArgumentOutOfRangeException: Specified argument was out of the range of valid values. Parameter name: index The Stack Trace: [ArgumentOutOfRangeException: Specified argument was out of the range of valid values. Parameter name: index] System.Web.UI.ControlCollection.get_Item(Int32 index) +8665582 System.Web.UI.WebControls.DataList.GetItem(ListItemType itemType, Int32 repeatIndex) +8667655 System.Web.UI.WebControls.DataList.System.Web.UI.WebControls.IRepeatInfoUser.GetItemStyle(ListItemType itemType, Int32 repeatIndex) +11 System.Web.UI.WebControls.RepeatInfo.RenderVerticalRepeater(HtmlTextWriter writer, IRepeatInfoUser user, Style controlStyle, WebControl baseControl) +8640873 System.Web.UI.WebControls.RepeatInfo.RenderRepeater(HtmlTextWriter writer, IRepeatInfoUser user, Style controlStyle, WebControl baseControl) +27 System.Web.UI.WebControls.DataList.RenderContents(HtmlTextWriter writer) +208 System.Web.UI.WebControls.BaseDataList.Render(HtmlTextWriter writer) +30 System.Web.UI.Control.RenderControlInternal(HtmlTextWriter writer, ControlAdapter adapter) +27 System.Web.UI.Control.RenderControl(HtmlTextWriter writer, ControlAdapter adapter) +99 System.Web.UI.Control.RenderControl(HtmlTextWriter writer) +25 System.Web.UI.Control.RenderChildrenInternal(HtmlTextWriter writer, ICollection children) +134 System.Web.UI.Control.RenderChildren(HtmlTextWriter writer) +19 System.Web.UI.HtmlControls.HtmlForm.RenderChildren(HtmlTextWriter writer) +163 System.Web.UI.HtmlControls.HtmlContainerControl.Render(HtmlTextWriter writer) +32 System.Web.UI.HtmlControls.HtmlForm.Render(HtmlTextWriter output) +51 System.Web.UI.Control.RenderControlInternal(HtmlTextWriter writer, ControlAdapter adapter) +27 System.Web.UI.Control.RenderControl(HtmlTextWriter writer, ControlAdapter adapter) +99 System.Web.UI.HtmlControls.HtmlForm.RenderControl(HtmlTextWriter writer) +40 System.Web.UI.Control.RenderChildrenInternal(HtmlTextWriter writer, ICollection children) +134 System.Web.UI.Control.RenderChildren(HtmlTextWriter writer) +19 System.Web.UI.Page.Render(HtmlTextWriter writer) +29 System.Web.UI.Control.RenderControlInternal(HtmlTextWriter writer, ControlAdapter adapter) +27 System.Web.UI.Control.RenderControl(HtmlTextWriter writer, ControlAdapter adapter) +99 System.Web.UI.Control.RenderControl(HtmlTextWriter writer) +25 System.Web.UI.Page.ProcessRequestMain(Boolean includeStagesBeforeAsyncPoint, Boolean includeStagesAfterAsyncPoint) +1266 The code Base class: public abstract class BaseTemplate : ITemplate { ListItemType _templateType; public BaseTemplate(ListItemType theTemplateType) { _templateType = theTemplateType; } public ListItemType ListItemType { get { return _templateType; } } #region ITemplate Members public void InstantiateIn(Control container) { PlaceHolder ph = new PlaceHolder(); container.Controls.Add(ph); Literal l = new Literal(); switch (_templateType) { case ListItemType.Header: { ph.Controls.Add(new LiteralControl(@"<table><tr>")); InstantiateInHeader(ph); ph.Controls.Add(new LiteralControl(@"</tr>")); break; } case ListItemType.Footer: { ph.Controls.Add(new LiteralControl(@"<tr>")); InstantiateInFooter(ph); ph.Controls.Add(new LiteralControl(@"</tr></table>")); break; } case ListItemType.Item: { ph.Controls.Add(new LiteralControl(@"<tr>")); InstantiateInItem(ph); ph.Controls.Add(new LiteralControl(@"<td>")); Button select = new Button(); select.ID = "btnSelect"; select.CommandName = "SelectRow"; select.Text = "Select"; ph.Controls.Add(select); ph.Controls.Add(new LiteralControl(@"</td>")); ph.Controls.Add(new LiteralControl(@"</tr>")); ph.DataBinding += new EventHandler(ph_DataBinding); break; } case ListItemType.AlternatingItem: { ph.Controls.Add(new LiteralControl(@"<tr>")); InstantiateInAlternatingItem(ph); ph.Controls.Add(new LiteralControl(@"<td>")); Button select = new Button(); select.ID = "btnSelect"; select.CommandName = "SelectRow"; select.Text = "Select"; ph.Controls.Add(select); ph.Controls.Add(new LiteralControl(@"</td>")); ph.Controls.Add(new LiteralControl(@"</tr>")); ph.DataBinding+=new EventHandler(ph_DataBinding); break; } case ListItemType.SelectedItem: { ph.Controls.Add(new LiteralControl(@"<tr>")); InstantiateInItem(ph); ph.Controls.Add(new LiteralControl(@"<td>")); Button edit = new Button(); edit.ID = "btnEdit"; edit.CommandName = "EditRow"; edit.Text = "Edit"; ph.Controls.Add(edit); Button delete = new Button(); delete.ID = "btnDelete"; delete.CommandName = "DeleteRow"; delete.Text = "Delete"; ph.Controls.Add(delete); ph.Controls.Add(new LiteralControl(@"</td>")); ph.Controls.Add(new LiteralControl(@"</tr>")); ph.DataBinding += new EventHandler(ph_DataBinding); break; } case ListItemType.EditItem: { ph.Controls.Add(new LiteralControl(@"<tr>")); InstantiateInEdit(ph); ph.Controls.Add(new LiteralControl(@"<td>")); Button save = new Button(); save.ID = "btnSave"; save.CommandName = "SaveRow"; save.Text = "Save"; ph.Controls.Add(save); Button cancel = new Button(); cancel.ID = "btnCancel"; cancel.CommandName = "CancelRow"; cancel.Text = "Cancel"; ph.Controls.Add(cancel); ph.Controls.Add(new LiteralControl(@"</td>")); ph.Controls.Add(new LiteralControl(@"</tr>")); ph.DataBinding += new EventHandler(ph_DataBinding); break; } case ListItemType.Separator: { InstantiateInSeperator(ph); break; } } } void ph_DataBinding(object sender, EventArgs e) { DataBindingOverride(sender, e); } /// <summary> /// the controls placed into the PlaceHolder will get wrapped in &lt;table&gt;&lt;tr&gt; &lt;/tr&gt;. I.e. you need to provide the column names wrapped in &lt;td&gt;&lt;/td&gt; tags. /// </summary> /// <param name="header"></param> public abstract void InstantiateInHeader(PlaceHolder ph); /// <summary> /// the controls will have a column added after them and so require each column to be properly wrapped in &lt;td&gt;&lt;/td&gt; tags. The &lt;tr&gt;&lt;/tr&gt; is handled in the base class. /// </summary> /// <param name="ph"></param> public abstract void InstantiateInItem(PlaceHolder ph); /// <summary> /// the controls will have a column added after them and so require each column to be properly wrapped in &lt;td&gt;&lt;/td&gt; tags. The &lt;tr&gt;&lt;/tr&gt; is handled in the base class. /// </summary> /// <param name="ph"></param> public abstract void InstantiateInAlternatingItem(PlaceHolder ph); /// <summary> /// the controls will have a column added after them and so require each column to be properly wrapped in &lt;td&gt;&lt;/td&gt; tags. The &lt;tr&gt;&lt;/tr&gt; is handled in the base class. /// </summary> /// <param name="ph"></param> public abstract void InstantiateInEdit(PlaceHolder ph); /// <summary> /// Any html used in the footer will have &lt;/tr&gt;&lt;table&gt; appended to the end. /// &lt;tr&gt; will be appended to the front. /// </summary> /// <param name="ph"></param> public abstract void InstantiateInFooter(PlaceHolder ph); /// <summary> /// the controls will have a column added after them and so require each column to be properly wrapped in &lt;td&gt;&lt;/td&gt; tags. The &lt;tr&gt;&lt;/tr&gt; is handled in the base class. /// Adds Delete and Edit Buttons after the table contents. /// </summary> /// <param name="ph"></param> public abstract void InstantiateInSelectedItem(PlaceHolder ph); /// <summary> /// The base class provides no &lt;tr&gt;&lt;/tr&gt; tags /// </summary> /// <param name="ph"></param> public abstract void InstantiateInSeperator(PlaceHolder ph); /// <summary> /// Use this method to bind the controls to their data. /// </summary> /// <param name="sender"></param> /// <param name="e"></param> public abstract void DataBindingOverride(object sender, EventArgs e); #endregion } Inheriting class: public class NominalGroupTemplate : BaseTemplate { public NominalGroupTemplate(ListItemType theListItemType) : base(theListItemType) { } public override void InstantiateInHeader(PlaceHolder ph) { ph.Controls.Add(new LiteralControl(@"<td>ID</td><td>Group</td><td>IsPositive</td>")); } public override void InstantiateInItem(PlaceHolder ph) { ph.Controls.Add(new LiteralControl(@"<td>")); Label lblID = new Label(); lblID.ID = "lblID"; ph.Controls.Add(lblID); ph.Controls.Add(new LiteralControl(@"</td><td>")); Label lblGroup = new Label(); lblGroup.ID = "lblGroup"; ph.Controls.Add(lblGroup); ph.Controls.Add(new LiteralControl(@"</td><td>")); CheckBox chkIsPositive = new CheckBox(); chkIsPositive.ID = "chkIsPositive"; chkIsPositive.Enabled = false; ph.Controls.Add(chkIsPositive); ph.Controls.Add(new LiteralControl(@"</td>")); } public override void InstantiateInAlternatingItem(PlaceHolder ph) { InstantiateInItem(ph); } public override void InstantiateInEdit(PlaceHolder ph) { ph.Controls.Add(new LiteralControl(@"<td>")); Label lblID = new Label(); lblID.ID = "lblID"; ph.Controls.Add(lblID); ph.Controls.Add(new LiteralControl(@"</td><td>")); TextBox txtGroup = new TextBox(); txtGroup.ID = "txtGroup"; txtGroup.Visible = true; txtGroup.Enabled = true ; ph.Controls.Add(txtGroup); ph.Controls.Add(new LiteralControl(@"</td><td>")); CheckBox chkIsPositive = new CheckBox(); chkIsPositive.ID = "chkIsPositive"; chkIsPositive.Visible = true; chkIsPositive.Enabled = true ; ph.Controls.Add(chkIsPositive); ph.Controls.Add(new LiteralControl(@"</td>")); } public override void InstantiateInFooter(PlaceHolder ph) { InstantiateInHeader(ph); } public override void InstantiateInSelectedItem(PlaceHolder ph) { ph.Controls.Add(new LiteralControl(@"<td>")); Label lblID = new Label(); lblID.ID = "lblID"; ph.Controls.Add(lblID); ph.Controls.Add(new LiteralControl(@"</td><td>")); TextBox txtGroup = new TextBox(); txtGroup.ID = "txtGroup"; txtGroup.Visible = true; txtGroup.Enabled = false; ph.Controls.Add(txtGroup); ph.Controls.Add(new LiteralControl(@"</td><td>")); CheckBox chkIsPositive = new CheckBox(); chkIsPositive.ID = "chkIsPositive"; chkIsPositive.Visible = true; chkIsPositive.Enabled = false; ph.Controls.Add(chkIsPositive); ph.Controls.Add(new LiteralControl(@"</td>")); } public override void InstantiateInSeperator(PlaceHolder ph) { } public override void DataBindingOverride(object sender, EventArgs e) { PlaceHolder ph = (PlaceHolder)sender; DataListItem li = (DataListItem)ph.NamingContainer; int id = Convert.ToInt32(DataBinder.Eval(li.DataItem, "ID")); string group = (string)DataBinder.Eval(li.DataItem, "Group"); bool isPositive = Convert.ToBoolean(DataBinder.Eval(li.DataItem, "IsPositive")); switch (this.ListItemType) { case ListItemType.Item: case ListItemType.AlternatingItem: { ((Label)ph.FindControl("lblID")).Text = id.ToString(); ((Label)ph.FindControl("lblGroup")).Text = group; ((CheckBox)ph.FindControl("chkIsPositive")).Text = isPositive.ToString(); break; } case ListItemType.EditItem: case ListItemType.SelectedItem: { ((TextBox)ph.FindControl("lblID")).Text = id.ToString(); ((TextBox)ph.FindControl("txtGroup")).Text = group; ((CheckBox)ph.FindControl("chkIsPositive")).Text = isPositive.ToString(); break; } } } } From here I added the control to a page the code behind public partial class NominalGroupbroke : System.Web.UI.UserControl { public void SetNominalGroupList(IList<BONominalGroup> theNominalGroups) { XElement data = Serialiser<BONominalGroup>.SerialiseObjectList(theNominalGroups); ViewState.Add("nominalGroups", data.ToString()); dlNominalGroup.DataSource = theNominalGroups; dlNominalGroup.DataBind(); } protected void Page_init() { dlNominalGroup.HeaderTemplate = new NominalGroupTemplate(ListItemType.Header); dlNominalGroup.ItemTemplate = new NominalGroupTemplate(ListItemType.Item); dlNominalGroup.AlternatingItemTemplate = new NominalGroupTemplate(ListItemType.AlternatingItem); dlNominalGroup.SeparatorTemplate = new NominalGroupTemplate(ListItemType.Separator); dlNominalGroup.SelectedItemTemplate = new NominalGroupTemplate(ListItemType.SelectedItem); dlNominalGroup.EditItemTemplate = new NominalGroupTemplate(ListItemType.EditItem); dlNominalGroup.FooterTemplate = new NominalGroupTemplate(ListItemType.Footer); } protected void Page_Load(object sender, EventArgs e) { dlNominalGroup.ItemCommand += new DataListCommandEventHandler(dlNominalGroup_ItemCommand); } void dlNominalGroup_Init(object sender, EventArgs e) { dlNominalGroup.HeaderTemplate = new NominalGroupTemplate(ListItemType.Header); dlNominalGroup.ItemTemplate = new NominalGroupTemplate(ListItemType.Item); dlNominalGroup.AlternatingItemTemplate = new NominalGroupTemplate(ListItemType.AlternatingItem); dlNominalGroup.SeparatorTemplate = new NominalGroupTemplate(ListItemType.Separator); dlNominalGroup.SelectedItemTemplate = new NominalGroupTemplate(ListItemType.SelectedItem); dlNominalGroup.EditItemTemplate = new NominalGroupTemplate(ListItemType.EditItem); dlNominalGroup.FooterTemplate = new NominalGroupTemplate(ListItemType.Footer); } void dlNominalGroup_DataBinding(object sender, EventArgs e) { } void deleteNominalGroup(int index) { XElement data = XElement.Parse(Convert.ToString( ViewState["nominalGroups"] )); IList<BONominalGroup> list = Serialiser<BONominalGroup>.DeserialiseObjectList(data); FENominalGroup.DeleteNominalGroup(list[index].ID); list.RemoveAt(index); data = Serialiser<BONominalGroup>.SerialiseObjectList(list); ViewState["nominalGroups"] = data.ToString(); dlNominalGroup.DataSource = list; dlNominalGroup.DataBind(); } void updateNominalGroup(DataListItem theItem) { XElement data = XElement.Parse(Convert.ToString( ViewState["nominalGroups"])); IList<BONominalGroup> list = Serialiser<BONominalGroup>.DeserialiseObjectList(data); BONominalGroup old = list[theItem.ItemIndex]; BONominalGroup n = new BONominalGroup(); byte id = Convert.ToByte(((TextBox)theItem.FindControl("lblID")).Text); string group = ((TextBox)theItem.FindControl("txtGroup")).Text; bool isPositive = Convert.ToBoolean(((CheckBox)theItem.FindControl("chkIsPositive")).Text); n.ID = id; n.Group = group; n.IsPositive = isPositive; FENominalGroup.UpdateNominalGroup(old, n); list[theItem.ItemIndex] = n; data = Serialiser<BONominalGroup>.SerialiseObjectList(list); ViewState["nominalGroups"] = data.ToString(); } void dlNominalGroup_ItemCommand(object source, DataListCommandEventArgs e) { DataList l = (DataList)source; switch (e.CommandName) { case "SelectRow": { if (l.EditItemIndex == -1) { l.SelectedIndex = e.Item.ItemIndex; l.EditItemIndex = -1; } break; } case "EditRow": { if (l.SelectedIndex == e.Item.ItemIndex) { l.EditItemIndex = e.Item.ItemIndex; } break; } case "DeleteRow": { deleteNominalGroup(e.Item.ItemIndex); l.EditItemIndex = -1; try { l.SelectedIndex = e.Item.ItemIndex; } catch { l.SelectedIndex = -1; } break; } case "CancelRow": { l.SelectedIndex = l.EditItemIndex; l.EditItemIndex = -1; break; } case "SaveRow": { updateNominalGroup(e.Item); try { l.SelectedIndex = e.Item.ItemIndex; } catch { l.SelectedIndex = -1; } l.EditItemIndex = -1; break; } } } Lots of code there, I'm afraid, but it should build. Thanks if anyone manages to spot my silliness. The BONominalGroup class (please ignore my crazy getHash override, I'm not proud of it). IAudit can just be an empty interface here and all will be fine. It used to inherit from another class, I have cleaned that out - so the serialization logic may be broken here. public class BONominalGroup { public BONominalGroup() #region Fields and properties private Int16 _ID; public Int16 ID { get { return _ID; } set { _ID = value; } } private string _group; public string Group { get { return _group; } set { _group = value; } } private bool _isPositve; public bool IsPositive { get { return _isPositve; } set { _isPositve = value; } } #endregion public override bool Equals(object obj) { bool retVal = false; BONominalGroup ng = obj as BONominalGroup; if (ng!=null) if (ng._group == this._group && ng._ID == this.ID && ng.IsPositive == this.IsPositive) { retVal = true; } return retVal; } public override int GetHashCode() { return ToString().GetHashCode(); } public override string ToString() { return "BONominalGroup{ID:" + this.ID.ToString() + ",Group:" + this.Group.ToString() + ",IsPositive:" + this.IsPositive.ToString() + "," + "}"; } #region IXmlSerializable Members public override void ReadXml(XmlReader reader) { reader.ReadStartElement("BONominalGroup"); this.ID = Convert.ToByte(reader.ReadElementString("id")); this.Group = reader.ReadElementString("group"); this.IsPositive = Convert.ToBoolean(reader.ReadElementString("isPositive")); base.ReadXml(reader); reader.ReadEndElement(); } public override void WriteXml(XmlWriter writer) { writer.WriteElementString("id", this.ID.ToString()); writer.WriteElementString("group", this.Group); writer.WriteElementString("isPositive", this.IsPositive.ToString()); // writer.WriteStartElement("BOBase"); // base.WriteXml(writer); writer.WriteEndElement(); } #endregion }

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  • Changing drag cursor in VirtualTreeView

    - by Coder12345
    When using VirtualTreeView drag operation by default is [doCopy,doMove]. Move operation is indicated by arrow pointer with small box and Copy operation is indicated by same pointer icon but with added [+] next to it. By default VT uses copy operation and if you press modifier key (SHIFT key) it modifies operation to move therefore removing the [+] from pointer. Here is what I need: reverse the operations (default would be move, with modifier key pressed - copy) and thus reverse pointer arrow too replace modifier key - CTRL instead of SHIFT read in an event which of the two operations occurred and start copy or move operation Any pointers into right direction(s) appreciated.

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  • Is this a situation where Qt Model/View architecture is not useful?

    - by csmithmaui
    Hi, I am writing a GUI based application where I read a string of values from serial port every few seconds and I need to display most of the values in some type graphical indicator(I was thinking of QprogressBar maybe) that displays the range and the value. Some of the other data that I am parsing from the string are the date and fault codes. Also, the data is hierarchical. I wanted to use the model/view architecture of Qt because I have been interested in MVC stuff for a while but have never quite wrapped my brain around how to implement it very well. As of now, I have subclassed QAbstractItemModel and in the model I read the serial port and wrap the items parsed from the string in a Tree data structure. I can view all of the data in a QtreeView with no issues. I have also began to subclass QAbstractItemView to build my custom view with all of the Graphical Indicators and such. This is where I am getting stuck. It seems to me that in order for me to design a view that knows how to display my custom model the view needs to know exactly how all of the data in the model is organized. Doesn't that defeat the purpose of Model/View? The QTreeView I tested the model with is basically just displaying the model as it is setup in the Tree structure but I don't want to do that because the data is not all of the same type. Is the type of data or the way you would like to present it to the user a determining factor in whether or not you should use this architecture? I always assumed it was just always better to design in an MVC style. It seems to me like it might have been better to just subclass QWidget and then read in from the serial port and update all of subwidgets(graphical indicators, labels, etc...) from the subclass. Essentially, do everything in one class. Does anybody understand this issue that can explain to me either what I am missing or why I shouldn't be doing it this way. As of now I am a little confused. Thanks so much for any help!

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  • How can I call VC# webservice methods without ArgumentException?

    - by Zarius
    Currently, I'm trying to write a small tray application that will show the status and provide control of a server-side application exposed over webservice. The webservice only has 3 operations: start, stop and status. When I call any of these operations in code, they throw an ArgumentException citing "An item with the same key has already been added". I am compiling the webservice on Visual C# Express 2008, and .NET 3.5. The Code: private TelnetConnClient Conn { get { return new TelnetConnClient(); } } private bool Connected //call webservice operations { get { return Conn.Status(); } set { if(value) Conn.Start(); else Conn.Stop(); } } The Stacktrace: A first chance exception of type 'System.ArgumentException' occurred in mscorlib.dll at System.ThrowHelper.ThrowArgumentException(ExceptionResource resource) at System.Collections.Generic.Dictionary`2.Insert(TKey key, TValue value, Boolean add) at System.ServiceModel.TransactionFlowAttribute.ApplyBehavior(OperationDescription description, BindingParameterCollection parameters) at System.ServiceModel.TransactionFlowAttribute.System.ServiceModel.Description.IOperationBehavior.AddBindingParameters(OperationDescription description, BindingParameterCollection parameters) at System.ServiceModel.Description.DispatcherBuilder.AddBindingParameters(ServiceEndpoint endpoint, BindingParameterCollection parameters) at System.ServiceModel.Description.DispatcherBuilder.BuildProxyBehavior(ServiceEndpoint serviceEndpoint, BindingParameterCollection& parameters) at System.ServiceModel.Channels.ServiceChannelFactory.BuildChannelFactory(ServiceEndpoint serviceEndpoint) at System.ServiceModel.ChannelFactory.CreateFactory() at System.ServiceModel.ChannelFactory.OnOpening() at System.ServiceModel.Channels.CommunicationObject.Open(TimeSpan timeout) at System.ServiceModel.ChannelFactory.EnsureOpened() at System.ServiceModel.ChannelFactory`1.CreateChannel(EndpointAddress address, Uri via) at System.ServiceModel.ChannelFactory`1.CreateChannel() at System.ServiceModel.ClientBase`1.CreateChannel() at System.ServiceModel.ClientBase`1.CreateChannelInternal() at System.ServiceModel.ClientBase`1.get_Channel() at KordiaConnect.ferries.TelnetConnClient.Start() in C:\My Dropbox\Coding\RTF\KordiaConnect\KordiaConnect\Service References\ferries\Reference.cs:line 86 at coldshark.ferries.Main.set_Connected(Boolean value) in C:\My Dropbox\Coding\RTF\KordiaConnect\KordiaConnect\Main.cs:line 22 at coldshark.ferries.Main.<.ctor>b__0(Object sender, EventArgs e) in C:\My Dropbox\Coding\RTF\KordiaConnect\KordiaConnect\Main.cs:line 43 at System.Windows.Forms.NotifyIcon.OnClick(EventArgs e) at System.Windows.Forms.NotifyIcon.WmMouseUp(Message& m, MouseButtons button) at System.Windows.Forms.NotifyIcon.WndProc(Message& msg) at System.Windows.Forms.NotifyIcon.NotifyIconNativeWindow.WndProc(Message& m) at System.Windows.Forms.NativeWindow.DebuggableCallback(IntPtr hWnd, Int32 msg, IntPtr wparam, IntPtr lparam) at System.Windows.Forms.UnsafeNativeMethods.PeekMessage(MSG& msg, HandleRef hwnd, Int32 msgMin, Int32 msgMax, Int32 remove) at System.Windows.Forms.Application.ComponentManager.System.Windows.Forms.UnsafeNativeMethods.IMsoComponentManager.FPushMessageLoop(Int32 dwComponentID, Int32 reason, Int32 pvLoopData) at System.Windows.Forms.Application.ThreadContext.RunMessageLoopInner(Int32 reason, ApplicationContext context) at System.Windows.Forms.Application.ThreadContext.RunMessageLoop(Int32 reason, ApplicationContext context) at System.Windows.Forms.Application.Run() at coldshark.ferries.Main..ctor() in C:\My Dropbox\Coding\RTF\KordiaConnect\KordiaConnect\Main.cs:line 55 I can just call the webservice from the web interface, but this application will give me a handy status notification icon, and I'd really love to know why the out-of-the-box auto-generated code fails for no particular reason.

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  • How to return the output of a recursive function in Clojure

    - by Silanglaya Valerio
    Hi everyone! I'm new to functional languages and clojure, so please bear with me... I'm trying to construct a list of functions, with either random parameters or constants. The function that constructs the list of functions is already working, though it doesn't return the function itself. I verified this using println. Here is the snippet: (def operations (list #(- %1 %2) #(+ %1 %2) #(* %1 %2) #(/ %1 %2))) (def parameters (list \u \v \w \x \y \z)) (def parameterlistcount 6) (def paramcount 2) (def opcount 4) (defn generateFunction "Generates a random function list" ([] (generateFunction 2 4 0.5 0.6 '())) ([pc maxdepth fp pp function] (if (and (> maxdepth 0) (< (rand) fp)) (dotimes [i 2] (println(conj (generateFunction pc (dec maxdepth) fp pp function) {:op (nth operations (rand-int opcount))}))) (if (and (< (rand) pp) (> pc 0)) (do (dec pc) (conj function {:param (nth parameters (rand-int parameterlistcount))})) (conj function {:const (rand-int 100)}))))) Any help will be appreciated, thanks!

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  • Making swap faster, easier to use and exception-safe

    - by FredOverflow
    I could not sleep last night and started thinking about std::swap. Here is the familiar C++98 version: template <typename T> void swap(T& a, T& b) { T c(a); a = b; b = c; } If a user-defined class Foo uses external ressources, this is inefficient. The common idiom is to provide a method void Foo::swap(Foo& other) and a specialization of std::swap<Foo>. Note that this does not work with class templates since you cannot partially specialize a function template, and overloading names in the std namespace is illegal. The solution is to write a template function in one's own namespace and rely on argument dependent lookup to find it. This depends critically on the client to follow the "using std::swap idiom" instead of calling std::swap directly. Very brittle. In C++0x, if Foo has a user-defined move constructor and a move assignment operator, providing a custom swap method and a std::swap<Foo> specialization has little to no performance benefit, because the C++0x version of std::swap uses efficient moves instead of copies: #include <utility> template <typename T> void swap(T& a, T& b) { T c(std::move(a)); a = std::move(b); b = std::move(c); } Not having to fiddle with swap anymore already takes a lot of burden away from the programmer. Current compilers do not generate move constructors and move assignment operators automatically yet, but as far as I know, this will change. The only problem left then is exception-safety, because in general, move operations are allowed to throw, and this opens up a whole can of worms. The question "What exactly is the state of a moved-from object?" complicates things further. Then I was thinking, what exactly are the semantics of std::swap in C++0x if everything goes fine? What is the state of the objects before and after the swap? Typically, swapping via move operations does not touch external resources, only the "flat" object representations themselves. So why not simply write a swap template that does exactly that: swap the object representations? #include <cstring> template <typename T> void swap(T& a, T& b) { unsigned char c[sizeof(T)]; memcpy( c, &a, sizeof(T)); memcpy(&a, &b, sizeof(T)); memcpy(&b, c, sizeof(T)); } This is as efficient as it gets: it simply blasts through raw memory. It does not require any intervention from the user: no special swap methods or move operations have to be defined. This means that it even works in C++98 (which does not have rvalue references, mind you). But even more importantly, we can now forget about the exception-safety issues, because memcpy never throws. I can see two potential problems with this approach: First, not all objects are meant to be swapped. If a class designer hides the copy constructor or the copy assignment operator, trying to swap objects of the class should fail at compile-time. We can simply introduce some dead code that checks whether copying and assignment are legal on the type: template <typename T> void swap(T& a, T& b) { if (false) // dead code, never executed { T c(a); // copy-constructible? a = b; // assignable? } unsigned char c[sizeof(T)]; std::memcpy( c, &a, sizeof(T)); std::memcpy(&a, &b, sizeof(T)); std::memcpy(&b, c, sizeof(T)); } Any decent compiler can trivially get rid of the dead code. (There are probably better ways to check the "swap conformance", but that is not the point. What matters is that it's possible). Second, some types might perform "unusual" actions in the copy constructor and copy assignment operator. For example, they might notify observers of their change. I deem this a minor issue, because such kinds of objects probably should not have provided copy operations in the first place. Please let me know what you think of this approach to swapping. Would it work in practice? Would you use it? Can you identify library types where this would break? Do you see additional problems? Discuss!

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  • EJB 3 Session Bean Design for Simple CRUD

    - by sdoca
    I am writing an application that's sole purpose in life is to do CRUD operations for maintaining records in database. There are relationships between some of the tables/entities. Most examples I've seen for creating session beans deals with complex business logic/operations that interact with many entities which I don't have. Since my application is so very basic, what would be the best design for the session bean(s)? I was thinking of having one session bean per entity which had CRUD the methods defined. Then I thought of combining all of those session beans into a single session bean. And then I found this blog entry which is intriguing, but I must admit I don't understand all of it (what is a ServiceFacade?). I'm leaning towards session bean/entity class, but would like to hear more experienced opinions. Thanks.

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  • What are some best practises and "rules of thumb" for creating database indexes?

    - by Ash
    I have an app, which cycles through a huge number of records in a database table and performs a number of SQL and .Net operations on records within that database (currently I am using Castle.ActiveRecord on PostgreSQL). I added some basic btree indexes on a couple of the feilds, and as you would expect, the peformance of the SQL operations increased substantially. Wanting to make the most of dbms performance I want to make some better educated choices about what I should index on all my projects. I understand that there is a detrement to performance when doing inserts (as the database needs to update the index, as well as the data), but what suggestions and best practices should I consider with creating database indexes? How do I best select the feilds/combination of fields for a set of database indexes (rules of thumb)? Also, how do I best select which index to use as a clustered index? And when it comes to the access method, under what conditions should I use a btree over a hash or a gist or a gin (what are they anyway?).

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  • Optimizing Haskell code

    - by Masse
    I'm trying to learn Haskell and after an article in reddit about Markov text chains, I decided to implement Markov text generation first in Python and now in Haskell. However I noticed that my python implementation is way faster than the Haskell version, even Haskell is compiled to native code. I am wondering what I should do to make the Haskell code run faster and for now I believe it's so much slower because of using Data.Map instead of hashmaps, but I'm not sure I'll post the Python code and Haskell as well. With the same data, Python takes around 3 seconds and Haskell is closer to 16 seconds. It comes without saying that I'll take any constructive criticism :). import random import re import cPickle class Markov: def __init__(self, filenames): self.filenames = filenames self.cache = self.train(self.readfiles()) picklefd = open("dump", "w") cPickle.dump(self.cache, picklefd) picklefd.close() def train(self, text): splitted = re.findall(r"(\w+|[.!?',])", text) print "Total of %d splitted words" % (len(splitted)) cache = {} for i in xrange(len(splitted)-2): pair = (splitted[i], splitted[i+1]) followup = splitted[i+2] if pair in cache: if followup not in cache[pair]: cache[pair][followup] = 1 else: cache[pair][followup] += 1 else: cache[pair] = {followup: 1} return cache def readfiles(self): data = "" for filename in self.filenames: fd = open(filename) data += fd.read() fd.close() return data def concat(self, words): sentence = "" for word in words: if word in "'\",?!:;.": sentence = sentence[0:-1] + word + " " else: sentence += word + " " return sentence def pickword(self, words): temp = [(k, words[k]) for k in words] results = [] for (word, n) in temp: results.append(word) if n > 1: for i in xrange(n-1): results.append(word) return random.choice(results) def gentext(self, words): allwords = [k for k in self.cache] (first, second) = random.choice(filter(lambda (a,b): a.istitle(), [k for k in self.cache])) sentence = [first, second] while len(sentence) < words or sentence[-1] is not ".": current = (sentence[-2], sentence[-1]) if current in self.cache: followup = self.pickword(self.cache[current]) sentence.append(followup) else: print "Wasn't able to. Breaking" break print self.concat(sentence) Markov(["76.txt"]) -- module Markov ( train , fox ) where import Debug.Trace import qualified Data.Map as M import qualified System.Random as R import qualified Data.ByteString.Char8 as B type Database = M.Map (B.ByteString, B.ByteString) (M.Map B.ByteString Int) train :: [B.ByteString] -> Database train (x:y:[]) = M.empty train (x:y:z:xs) = let l = train (y:z:xs) in M.insertWith' (\new old -> M.insertWith' (+) z 1 old) (x, y) (M.singleton z 1) `seq` l main = do contents <- B.readFile "76.txt" print $ train $ B.words contents fox="The quick brown fox jumps over the brown fox who is slow jumps over the brown fox who is dead."

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  • How to design this ?

    - by Akku
    how can i make this entire process as 1 single event??? http://code.google.com/apis/visualization/documentation/dev/dsl_get_started.html and draw the chart on single click? I am new to servlets please guide me When a user clicks the "go " button with some input. The data goes to the servlet say "Test3". The servlet processes the data by the user and generates/feeds the data table dynamically Then I call the html page to draw the chart as shown in the tutorial link above. The problem is when I call the servlet it gives me a long json string in the browser as given in the tutorials "google.visualization.Query.setResponse({version:'0.6',status:'ok',sig:'1333639331',table:{cols:[{............................" Then when i manually call the html page to draw the chart i am see the chart. But when I call html page directly using the request dispatcher via the servlet I dont get the result. This is my code and o/p...... I need sugession as to how should be my approach to call the chart public class Test3 extends HttpServlet implements DataTableGenerator { protected void processRequest(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { DataSourceHelper.executeDataSourceServletFlow(request, response, this , isRestrictedAccessMode() ); RequestDispatcher rd; rd = request.getRequestDispatcher("new.html");// it call's the html page which draws the chart as per the data added by the servlet..... rd.include(request, response);//forward(request, response); @Override public Capabilities getCapabilities() { return Capabilities.NONE; } protected boolean isRestrictedAccessMode() { return false; } @Override public DataTable generateDataTable(Query query, HttpServletRequest request) { // Create a data table. DataTable data = new DataTable(); ArrayList<ColumnDescription> cd = new ArrayList<ColumnDescription>(); cd.add(new ColumnDescription("name", ValueType.TEXT, "Animal name")); cd.add......... I get the following result along with unprocessed html page google.visualization.Query.setResponse({version:'0.6',statu..... <html> <head> <title>Getting Started Example</title> .... Entire html page as it is on the Browser. What I need is when a user clicks the go button the servlet should process the data and call the html page to draw the chart....Without the json string appearing on the browser.(all in one user click) What should be my approach or how should i design this.... there are no error in the code. since when i run the servlet i get the json string on the browser and then when i run the html page manually i get the chart drawn. So how can I do (servlet processing + html page drawing chart as final result) at one go without the long json string appearing on the browser. There is no problem with the html code....

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  • Decode the string encoded through php in javascript

    - by Pankaj Khurana
    Hi, I am working on a facebook page in which i have used ajax & response is returned in json format. I have encoded the string in php. Now i want to decode that string in javascript. foreach($feedbackdetails as $feedbackdetail) { $str.= '<div class="tweet"> <img style="cursor:pointer;" id="imgVoteUp" src="http://myserver/facebook/vote_up.gif" alt="Vote Up" title="Vote Up" onclick="saveVote('.$feedbackdetail[pk_feedbackid].',1)" /> : '.$feedbackdetail[upvotecount].' <img style="cursor:pointer;" id="imgVoteDown" src="http://myserver/facebook/vote_down.gif" alt="Vote Down" title="Vote Down" onclick="saveVote('.$feedbackdetail[pk_feedbackid].',0)" /> : '.$feedbackdetail[downvotecount].' <p class="'.$pclass.'">'.$feedbackdetail[title].' by '.$feedbackdetail[name].'<br>'.$feedbackdetail[description].'</p></div>'; } $str=urlencode($str); echo '{"fbml_test":"'.$str.'"}'; Javascript Function: function saveVote(id,type,class) { contentdiv='div_'+id; processdiv='processdiv_'+id; document.getElementById(processdiv).setInnerXHTML('<span id="caric"><center><img src="http://static.ak.fbcdn.net/rsrc.php/z5R48/hash/ejut8v2y.gif" /></center></span>'); posturl='http://myserver/facebook/vote.php'; if(class==0) { class='firstmessage'; } else { class='message'; } var queryString = "?id="+id+"&type="+type+"&pclass="+class; posturl = posturl +queryString; ajax = new Ajax(); ajax.responseType = Ajax.JSON; ajax.requireLogin = true; ajax.ondone = function(data) { document.getElementById('caric').setStyle('display','none'); //new Dialog().showMessage('Dialog',data); if(data.error) { new Dialog().showMessage('Dialog',data.error); } if(data.fbml_test) { document.getElementById(contentdiv).setInnerFBML(data)); } //div_id.setInnerFBML(data); } ajax.post(posturl); } Right now i am getting encoded string how can i change it? Please help me on this Thanks Pankaj

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  • Running out of memory with UIImage creation on an offscreen Bitmap Context by NSOperation

    - by sigsegv
    I have an app with multiple UIView subclasses that acts as pages for a UIScrollView. UIViews are moved back and forth to provide a seamless experience to the user. Since the content of the views is rather slow to draw, it's rendered on a single shared CGBitmapContext guarded by locks by NSOperation subclasses - executed one at once in an NSOperationQueue - wrapped up in an UIImage and then used by the main thread to update the content of the views. -(void)main { NSAutoreleasePool * pool = [[NSAutoreleasePool alloc]init]; if([self isCancelled]) { return; } if(nil == data) { return; } // Buffer is the shared instance of a CG Bitmap Context wrapper class // data is a dictionary CGImageRef img = [buffer imageCreateWithData:data]; UIImage * image = [[UIImage alloc]initWithCGImage:img]; CGImageRelease(img); if([self isCancelled]) { [image release]; return; } NSDictionary * result = [[NSDictionary alloc]initWithObjectsAndKeys:image,@"image",id,@"id",nil]; // target is the instance of the UIView subclass that will use // the image [target performSelectorOnMainThread:@selector(updateContentWithData:) withObject:result waitUntilDone:NO]; [result release]; [image release]; [pool release]; } The updateContentWithData: of the UIView subclass performed on the main thread is just as simple -(void)updateContentWithData:(NSDictionary *)someData { NSDictionary * data = [someData retain]; if([[data valueForKey:@"id"]isEqualToString:[self pendingRequestId]]) { UIImage * image = [data valueForKey:@"image"]; [self setCurrentImage:image]; [self setNeedsDisplay]; } // If the image has not been retained, it should be released together // with the dictionary retaining it [data release]; } The drawLayer:inContext: method of the subclass will just get the CGImage from the UIImage and use it to update the backing layer or part of it. No retain or release is involved in the process. The problem is that after a while I run out of memory. The number of the UIViews is static. CGImageRef and UIImage are created, retained and released correctly (or so it seems to me). Instruments does not show any leaks, just the free memory available dip constantly, rise a few times, and then dip even lower until the application is terminated. The app cycles through about 2-300 of the aforementioned pages before that, but I would expect to have the memory usage reach a more or less stable level of used memory after a bunch of pages have been already skimmed at fast speed or, since the images are up to 3MB in size, deplete way earlier. Any suggestion will be greatly appreciated.

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