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  • Divide a path into N sections using Java or PostgreSQL/PostGIS

    - by Guido
    Imagine a GPS tracking system that is following the position of several objects. The points are stored in a database (PostgreSQL + PostGIS). Each path is composed by a different number of points. That is the reason why, in order to compare a pair of paths, I need to divide every path in a set of 100 points. Do you know any PostGIS function that already implement this algorithm? I've not been able to find it. If not, I'd like to solve it using Java. In this case I'd like to know an efficient and easy to implement algorithm to divide a path into N points. The most simple example could be to divide this path into three points: position 1 : x=1, y=2 position 2 : x=1, y=3 And the result should be: position 1 : x=1, y=2 (starting point) position 2 : x=5, y=2.5 position 3 : x=9, y=3 (end point) Edit: By 'compare a pair of paths' I mean to calculate the distance between two paths. I plan to divide each path in 100 points, and sum the euclidean distance between each one of these points as the distance between the two paths.

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  • Error handling in PHP

    - by Industrial
    Hi guys, We're building a PHP app based on Good old MVC (codeigniter framework) and have run into trouble with a massive chained action that consists of multiple model calls, that together is a part of a big transaction to the database. We want to be able to do a list of actions and get a status report of each one back from the function, whatever the outcome is. Our first initial idea was to utilize the exceptions of PHP5, but since we want to also need status messages that doesnt break the execution of the script, this was our solution that we came up with. It goes a little something like this: $sku = $this->addSku( $name ); if ($sku === false) { $status[] = 'Something gone terrible wrong'; $this->db->trans_rollback(); return $status; } $image= $this->addImage( $filename); if ($image=== false) { $error[] = 'Image could not be uploaded, check filesize'; $this->db->trans_rollback(); return $status; } Our controller looks like this: $var = $this->products->addProductGroup($array); if (is_array($var)) { foreach ($var as $error) { echo $error . '<br />'; } } It appears to be a very fragile solution to do what we need, but it's neither scalable, neither effective when compared to pure PHP exceptions for instance. Is this really the way that this kind of stuff generally is handled in MVC based apps? Thanks!

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  • Use Lambda in Attribute constructor to get method's parameters

    - by Anthony Shaw
    I'm not even sure if this is possible, but I've exhausted all of my ideas trying to figure this out, so I figured I'd send this out to the community and see what you thought. And, if it's not possible, maybe you'd have some ideas as well. I'm trying to make an Attribute class that I can add to a method that would allow me to use a lambda expression to get each parameter of the method public ExampleAttribute : Attribute { public object Value { get; set; } public ExampleAttribute(--something here to make the lambda work--, object value) { Value = value; } } I'd like to be able to something like this below: [Example(x=x.Id, 4)] [Example(x=x.filter, "string value")] public ActionResult Index(int Id, string filter) { return View(); } I understand that I might be completely dreaming with this idea. I'm basically trying to write a model to allow for self-documenting REST API Documentation. In a recent project here at work we wrote a dozen or so services with 5 to 15 methods on each, I figure it's easier to write something to do this, than to hand code a documentation page for each. I would plan to eventually release this as an open-source project once I have it in a place that I feel it's releasable.

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  • Getting identity from Ado.Net Update command

    - by rboarman
    My scenario is simple. I am trying to persist a DataSet and have the identity column filled in so I can add child records. Here's what I've got so far: using (SqlConnection connection = new SqlConnection(connStr)) { SqlDataAdapter adapter = new SqlDataAdapter("select * from assets where 0 = 1", connection); adapter.MissingMappingAction = MissingMappingAction.Passthrough; adapter.MissingSchemaAction = MissingSchemaAction.AddWithKey; SqlCommandBuilder cb = new SqlCommandBuilder(adapter); var insertCmd = cb.GetInsertCommand(true); insertCmd.Connection = connection; connection.Open(); adapter.InsertCommand = insertCmd; adapter.InsertCommand.CommandText += "; set ? = SCOPE_IDENTITY()"; adapter.InsertCommand.UpdatedRowSource = UpdateRowSource.OutputParameters; var param = new SqlParameter("RowId", SqlDbType.Int); param.SourceColumn = "RowId"; param.Direction = ParameterDirection.Output; adapter.InsertCommand.Parameters.Add(param); SqlTransaction transaction = connection.BeginTransaction(); insertCmd.Transaction = transaction; try { assetsImported = adapter.Update(dataSet.Tables["Assets"]); transaction.Commit(); } catch (Exception ex) { transaction.Rollback(); // Log an error } connection.Close(); } The first thing that I noticed, besides the fact that the identity value is not making its way back into the DataSet, is that my change to add the scope_identity select statement to the insert command is not being executed. Looking at the query using Profiler, I do not see my addition to the insert command. Questions: 1) Why is my addition to the insert command not making its way to the sql being executed on the database? 2) Is there a simpler way to have my DataSet refreshed with the identity values of the inserted rows? 3) Should I use the OnRowUpdated callback to add my child records? My plan was to loop through the rows after the Update() call and add children as needed. Thank you in advance. Rick

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  • ECM (Niche Vs Mass Market)

    - by Luj Reyes
    Hi Everyone, I recently started a little company with a couple of guys. Ours is the typical startup, a lot of ideas, dreams, talent and work hours :P. Our initial business plan was to develop a DM (Document Manager) with several features found on DropBox and other tools but with a big differentiator. Then we got in the team this Business Guy (I must say that several of us could be called 'Business Guys' but we are mainly hackers, he is just Another 'Networking Guy'), and along with him came this market analysis for a DM aimed at a very specific and narrow niche. We have many elements to believe in his market study and the idea is the classic "The market is X million, so if we grab a 10%...", and the market is really there to grab because all big providers deemed it too little and fled, let's say that the market is 5 million USD and demand very specific features. If we decide to go for this niche product we face a sales cycle of about 7 months, and the main goal of these revenue is to develop more ambitious projects. (Institutional VC is out of the question if you want to keep a marginal ownership of your company in my country). The only overlap between the niche and the mass market product features is the ability to store documents; everything else requires that we focus all of our efforts towards one or the other. I've studied a lot about the differences between Mass and Niche Markets, but I want to hear from people with actual experience. So everything comes down to this: If you have a really “saleable” idea what is the right thing to do: to go for the niche or go for the big prize and target primarily the mass market? Thanks for your input

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  • Safe way to set computed environment variables

    - by sfink
    I have a bash script that I am modifying to accept key=value pairs from stdin. (It is spawned by xinetd.) How can I safely convert those key=value pairs into environment variables for subprocesses? I plan to only allow keys that begin with a predefined prefix "CMK_", to avoid IFS or any other "dangerous" variable getting set. But the simplistic approach function import () { local IFS="=" while read key val; do case "$key" in CMK_*) eval "$key=$val";; esac done } is horribly insecure because $val could contain all sorts of nasty stuff. This seems like it would work: shopt -s extglob function import () { NORMAL_IFS="$IFS" local IFS="=" while read key val; do case "$key" in CMK_*([a-zA-Z_]) ) IFS="$NORMAL_IFS" eval $key='$val' IFS="=" ;; esac done } but (1) it uses the funky extglob thing that I've never used before, and (2) it's complicated enough that I can't be comfortable that it's secure. My goal, to be specific, is to allow key=value settings to pass through the bash script into the environment of called processes. It is up to the subprocesses to deal with potentially hostile values getting set. I am modifying someone else's script, so I don't want to just convert it to Perl and be done with it. I would also rather not change it around to invoke the subprocesses differently, something like #!/bin/sh ...start of script... perl -nle '($k,$v)=split(/=/,$_,2); $ENV{$k}=$v if $k =~ /^CMK_/; END { exec("subprocess") }' ...end of script...

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  • Conditional macro expansion

    - by Dave DeLong
    Heads up: This is a weird question. I've got some really useful macros that I like to use to simplify some logging. For example I can do Log(@"My message with arguments: %@, %@, %@", @"arg1", @"arg2", @"arg3"), and that will get expanded into a more complex method invocation that includes things like self, _cmd, __FILE__, __LINE__, etc, so that I can easily track where things are getting logged. This works great. Now I'd like to expand my macros to not only work with Objective-C methods, but general C functions. The problem is the self and _cmd portions that are in the macro expansion. These two parameters don't exist in C functions. Ideally, I'd like to be able to use this same set of macros within C functions, but I'm running into problems. When I use (for example) my Log() macro, I get compiler warnings about self and _cmd being undeclared (which makes total sense). My first thought was to do something like the following (in my macro): if (thisFunctionIsACFunction) { DoLogging(nil, nil, format, ##__VA_ARGS__); } else { DoLogging(self, _cmd, format, ##__VA_ARGS__); } This still produces compiler warnings, since the entire if() statement is substituted in place of the macro, resulting in errors with the self and _cmd keywords (even though they will never be executed during function execution). My next thought was to do something like this (in my macro): if (thisFunctionIsACFunction) { #define SELF nil #define CMD nil } else { #define SELF self #define CMD _cmd } DoLogging(SELF, CMD, format, ##__VA_ARGS__); That doesn't work, unfortunately. I get "error: '#' is not followed by a macro parameter" on my first #define. My other thought was to create a second set of macros, specifically for use in C functions. This reeks of a bad code smell, and I really don't want to do this. Is there some way I can use the same set of macros from within both Objective-C methods and C functions, and only reference self and _cmd if the macro is in an Objective-C method?

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  • How to distinguish between two different UDP clients on the same IP address?

    - by Ricket
    I'm writing a UDP server, which is a first for me; I've only done a bit of TCP communications. And I'm having trouble figuring out exactly how to distinguish which user is which, since UDP deals only with packets rather than connections and I therefore cannot tell exactly who I'm communicating with. Here is pseudocode of my current server loop: DatagramPacket p; socket.receive(p); // now p contains the user's IP and port, and the data int key = getKey(p); if(key == 0) { // connection request key = makeKey(p); clients.add(key, p.ip); send(p.ip, p.port, key); // give the user his key } else { // user has a key // verify key belongs to that IP address // lookup the user's session data based on the key // react to the packet in the context of the session } When designing this, I kept in mind these points: Multiple users may exist on the same IP address, due to the presence of routers, therefore users must have a separate identification key. Packets can be spoofed, so the key should be checked against its original IP address and ignored if a different IP tries to use the key. The outbound port on the client side might change among packets. Is that third assumption correct, or can I simply assume that one user = one IP+port combination? Is this commonly done, or should I continue to create a special key like I am currently doing? I'm not completely clear on how TCP negotiates a connection so if you think I should model it off of TCP then please link me to a good tutorial or something on TCP's SYN/SYNACK/ACK mess. Also note, I do have a provision to resend a key, if an IP sends a 0 and that IP already has a pending key; I omitted it to keep the snippet simple. I understand that UDP is not guaranteed to arrive, and I plan to add reliability to the main packet handling code later as well.

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  • calling .ajax() from an eventHandler c# asp.ent

    - by ibininja
    Good day...! In the code behind (upload.aspx) I have an event that returns the number of bytes being streamed; and as I debug it, it works fine. I wanted to reflect the numbers returned from the eventHandler on a progress bar and this is where I got lost. I tried using jQuery's .ajax() function. this is how I implemented it: In the EventHandler in my code behind I added this code to call the .ajax() function: Page.ClientScript.RegisterStartupScript(this.GetType(), "UpdateProgress", "<script type='text/javascript'>updateProgress();</script>"); My plan is whenever the eventHandler function changes the values of bytes being streamed it calls the javascript function "updateProgress()" The .ajax() function "UpdateProgress()" is as: function updateProgress() { $.ajax({ type: "POST", url: "upload.aspx/GetData", data: "{}", contentType: "application/json; charset=utf-8", dataType: "json", async: true, success: function (msg) { $("#progressbar").progressbar("option", "value", msg.d); } }); } I made sure that the function GetData() is [System.Web.Services.WebMethod] and that it is static as well. so the workflow of what I am trying to implement is as: - Click On Upload button - The Behind code starts executing and EventHandler triggers - The EventHandler calls .ajax() function - The .ajax() function retrieves the bytes being streamed and updates progress bar. When I ran the code; all runs well except that the .ajax() is only executed when upload is finished (and progress bar also updates only when finished upload); even though I call .ajax() function every time in the eventHandler function as reflected above... What am I doing wrong? Am I thinking of this right? is there anything else I should add maybe an updatePanel or something? thank you

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  • Total Order between !different! volatile variables?

    - by andreas
    Hi all, Consider the following Java code: volatile boolean v1 = false; volatile boolean v2 = false; //Thread A v1 = true; if (v2) System.out.println("v2 was true"); //Thread B v2 = true; if (v1) System.out.println("v1 was true"); If there was a globally visible total order for volatile accesses then at least one println would always be reached. Is that actually guaranteed by the Java Standard? Or is an execution like this possible: A: v1 = true; B: v2 = true; A: read v2 = false; B: read v1 = false; A: v2 = true becomes visible (after the if) B: v1 = true becomes visible (after the if) I could only find statements about accesses to the same volatile variable in the Standard (but I might be missing something). "A write to a volatile variable (§8.3.1.4) v synchronizes-with all subsequent reads of v by any thread (where subsequent is defined according to the synchronization order)." http://java.sun.com/docs/books/jls/third_edition/html/memory.html#17.4.4 Thanks!

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  • Java performance issue

    - by Colby77
    Hi, I've got a question related to java performance and method execution. In my app there are a lot of place where I have to validate some parameter, so I've written a Validator class and put all the validation methods into it. Here is an example: public class NumberValidator { public static short shortValidator(String s) throws ValidationException{ try{ short sh = Short.parseShort(s); if(sh < 1){ throw new ValidationException(); } return sh; }catch (Exception e) { throw new ValidationException("The parameter is wrong!"); } } ... But I'm thinking about that. Is this OK? It's OO and modularized, but - considering performance - is it a good idea? What if I had awful lot of invocation at the same time? The snippet above is short and fast, but there are some methods that take more time. What happens when there are a lot of calling to a static method or an instance method in the same class and the method is not synchronized? All the calling methods have to fall in line and the JVM executes them sequentially? Is it a good idea to have some class that are identical to the above-mentioned and randomly call their identical methods? I think it is not, because "Don't repeat yourself " and "Duplication is Evil" etc. But what about performance? Thanks is advance.

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  • Qt - QWebView Problem

    - by user547057
    Hi, I have a PyQt gui script which consists of a QWebView widget. I'm trying to send a GET request, i.e go to a page, fill a form and hit click using the code at the bottom of this question. Since i'm dealing with the documentElement(a QWebElement) of the webview, I need to place all DOM actions in a separate function(which I have named fillForm) and connect the loadFinished() signal into the function. Without connecting the signal, the document will not have loaded and I won't be able to get the elements I want. I'm able to submit the form correctly and get the proper response from the webpage. The problem i'm having is that, the above leads to a sort of infinite loop. This is because the webpage gets reloaded each time a new page is loaded, so the form gets filled each and every single time without stopping. I'd like to know if there's some way of finding out whether the WebView's page has loaded fully, non-asynchronously or maybe pause execution of the script(without freezing the gui) until the whole document has loaded. I'm unable to come up with a satisfactory solution(my idea consisted of keeping a global variable to track clicks) to this problem. I would appreciate it if someone could help me out with a better way to tackle this. Thanks! Here's the code i'm using import sys from PyQt4.QtCore import * from PyQt4.QtGui import * from PyQt4.QtWebKit import * from PyQt4 import QtCore app = QApplication(sys.argv) web = QWebView() web.load(QUrl("http://mywebsite.com")) def fillForm(): doc = web.page().mainFrame().documentElement() searchform = doc.findFirst("input[type=text]") searchform.setAttribute("value", "hello") button = doc.findFirst("input[type=submit]") button.evaluateJavaScript("click()") QtCore.QObject.connect(web, QtCore.SIGNAL("loadFinished"), fillForm) web.show() sys.exit(app.exec_())

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  • BackgroundWorker might be causing my application to hang

    - by alexD
    I have a Form that uses a BackgroundWorker to execute a series of tests. I use the ProgressChanged event to send messages to the main thread, which then does all of the updates on the UI. I've combed through my code to make sure I'm not doing anything to the UI in the background worker. There are no while loops in my code and the BackgroundWorker has a finite execution time (measured in seconds or minutes). However, for some reason when I lock my computer, often times the application will be hung when I log back in. The thing is, the BackgroundWorker isn't even running when this happens. The reason I believe it is related to the BackgroundWorker though is because the form only hangs when the BackgroundWorker has been executed since the application was loaded (it only runs when given a certain user input). I pass this thread a List of TreeNodes from a TreeView in my UI through the RunWorkerAsync method, but I only read those nodes in the worker thread..any modifications I make to them is done in the UI thread through the progressChanged event. I do use Thread.Sleep in my worker thread to execute tests at timed intervals (which involves sending messages over a TCP socket, which was not created in the worker thread). I am completely perplexed as to why my application might be hanging. I'm sure I'm doing something 'illegal' somewhere, I just don't know what.

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  • 1k of Program Space, 64 bytes of RAM. Is assembly an absolute must?

    - by Earlz
    (If your lazy see bottom for TL;DR) Hello, I am planning to build a new (prototype) project dealing with physical computing. Basically, I have wires. These wires all need to have their voltage read at the same time. More than a few hundred microseconds difference between the readings of each wire will completely screw it up. The Arduino takes about 114 microseconds. So the most I could read is 2 or 3 wires before the latency would skew the accuracy of the readings. So my plan is to have an Arduino as the "master" of an array of ATTinys. The arduino is pretty cramped for space, but it's a massive playground compared to the tinys. An ATTiny13A has 1k of flash ROM(program space), 64 bytes of RAM, and 64 bytes of (not-durable and slow) EEPROM. (I'm choosing this for price as well as size) The ATTinys in my system will not do much. Basically, all they will do is wait for a signal from the Master, and then read the voltage of 1 or 2 wires and store it in RAM(or possibly EEPROM if it's that cramped). And then send it to the Master using only 1 wire for data.(no room for more than that!). So far then, all I should have to do is implement trivial voltage reading code (using built in ADC). But this communication bit I'm worried about. Do you think a communication protocol(using just 1 wire!) could even be implemented in such constraints? TL;DR: In less than 1k of program space and 64 bytes of RAM(and 64 bytes of EEPROM) do you think it is possible to implement a 1 wire communication protocol? Would I need to drop to assembly to make it fit? I know that currently my Arduino programs linking to the Wiring library are over 8k, so I'm a bit concerned.

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  • Java (or possibly other languages) learning path

    - by bgo
    I am familiar (as a self-learner) with C, python and php such that i can solve some problems involving simple steps (for example, i easily do calculations for physics lab reports with python which normally would take 4x-5x times longer with a calculator). The point here is, as doing such things, i learnt the idea / concepts of programming language and problem solving along with oop or fuctional programming etc. Recently i have started Java and, with the familiarity of other languages, i am doing well for starters but i need guidence. -I am thinking of learning syntax from sun java tutorials and then practicing with codingbat.com or similar sites. I need a reference book that i can study deeper aspects of the topics i am learning. What do you suggest about these? -The problem is (and always have been) the lack of practice. I need coding and problem-solving practices sources. I stuck at the point where i can't figure out what to do next. Can you suggest any source (possibly like codingbat)? If i could plan a learning trail, i can progress faster and efficiently. So i need ideas, comments, suggestions. Thanks in advance.

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  • Multiple threads modifying a collection in Java??

    - by posdef
    Hi, The project I am working on requires a whole bunch of queries towards a database. In principle there are two types of queries I am using: read from excel file, check for a couple of parameters and do a query for hits in the database. These hits are then registered as a series of custom classes. Any hit may (and most likely will) occur more than once so this part of the code checks and updates the occurrence in a custom list implementation that extends ArrayList. for each hit found, do a detail query and parse the output, so that the classes created in (I) get detailed info. I figured I would use multiple threads to optimize time-wise. However I can't really come up with a good way to solve the problem that occurs with the collection these items are stored in. To elaborate a little bit; throughout the execution objects are supposed to be modified by both (I) and (II). I deliberately didn't c/p any code, as it would be big chunks of code to make any sense.. I hope it make some sense with the description above. Thanks,

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  • TypeError: Error #1009 - (Null reference error) With Flash.

    - by Wind Chimez
    I am not an expert in flash, but i do work with AS and tweak Flash projects , though not having deep expertise in it. Currently i need to revamp a flash website done by one another guy, and the code base given to me, upon execution is throwing the following error. "--- TypeError: Error #1009: Cannot access a property or method of a null object reference. at NewSite_fla::MainTimeline/__setProp_ContactOutP1_ContactOut_Contents_0() at NewSite_fla::MainTimeline/frame1() --" The structure of the project is like, it has the different sections split into different movie clips. There is no single main timeline, but click actions on different areas of seperate movie clips will take them between one another. All the AS logic of event handling are written inline in FLA , no seperate Document class exists. Preloader Movie clip is the first one getting loaded. As i understood the error is getting thrown initially itself, and it is not happening due to any Action script logic written inline, because it is throwing error even before hitting the first inline AS code. I am not able to figure Out what exactly it causing the problem, or where to resolve it. I really got stuck at this point. Any help will be great.I had not seen the particular solution i am looking for anywhere yet, though Error #1009 is common. I uploaded the fla, here ( http://tinyurl.com/249e95p ), for reference.It may not be working , since the included/refered video files and all are not there, but reviwing the action code/movie clips will be possible. Please let me know if somebody will be able to trace the issue exactly.

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  • Using the Apple Scripting bridge with Mail to send an attachment causes the message background to go

    - by Naym
    Hello, When I use the Apple Scripting Bridge to send a message with an attachment the background of the message is set to black which is a problem because the text is also black. The code in question is: MailApplication *mail = [SBApplication applicationWithBundleIdentifier:@"com.apple.Mail"]; /* create a new outgoing message object */ MailOutgoingMessage *emailMessage = [[[mail classForScriptingClass:@"outgoing message"] alloc] initWithProperties: [NSDictionary dictionaryWithObjectsAndKeys: emailSubject, @"subject", [self composeEmailBody], @"content", nil]]; /* add the object to the mail app */ [[mail outgoingMessages] addObject: emailMessage]; /* set the sender, show the message */ emailMessage.sender = [NSString stringWithFormat:@"%@ <%@>",[[[mail accounts] objectAtIndex:playerOptions.mailAccount] fullName],[[[[mail accounts] objectAtIndex:playerOptions.mailAccount] emailAddresses] objectAtIndex:0]]; emailMessage.visible = YES; /* create a new recipient and add it to the recipients list */ MailToRecipient *theRecipient = [[[mail classForScriptingClass:@"to recipient"] alloc] initWithProperties: [NSDictionary dictionaryWithObjectsAndKeys: opponentEmail, @"address", nil]]; [emailMessage.toRecipients addObject: theRecipient]; /* add an attachment, if one was specified */ if ( [playerInfo.gameFile length] > 0 ) { /* create an attachment object */ MailAttachment *theAttachment = [[[mail classForScriptingClass:@"attachment"] alloc] initWithProperties: [NSDictionary dictionaryWithObjectsAndKeys: playerInfo.gameFile, @"fileName", nil]]; /* add it to the list of attachments */ [[emailMessage.content attachments] addObject: theAttachment]; } /* send the message */ [emailMessage send]; The actual change to the background colour occurs on the second last line, which is: [[emailMessage.content attachments] addObject: theAttachment]; The code sections above are essentially lifted from the SBSendMail example code from Apple. At this stage I've really only made the changes necessary to integrate with the data from my application. If I build and run the SBSendMail example after freshly downloading it from Apple the message background is also changed to black with execution of the same line. It does not appear to matter which type of file is attached, where it is located, or on which computer or operating system is used. This could be a bug in Apple's scripting bridge but has anyone come across this problem and found a solution? ALternatively does anyone know if the background colour of a MailOutgoingMessage instance can be changed with the scripting bridge? Thanks for any assistance with this, Naym.

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  • Index Tuning for SSIS tasks

    - by Raj More
    I am loading tables in my warehouse using SSIS. Since my SSIS is slow, it seemed like a great idea to build indexes on the tables. There are no primary keys (and therefore, foreign keys), indexes (clustered or otherwise), constraints, on this warehouse. In other words, it is 100% efficiency free. We are going to put indexes based on usage - by analyzing new queries and current query performance. So, instead of doing it our old fashioned sweat and grunt way of actually reading the SQL statements and execution plans, I thought I'd put the shiny new Database Engine Tuning Advisor to use. I turned SQL logging off in my SSIS package and ran a "Tuning" trace, saved it to a table and analyzed the output in the Tuning Advisor. Most of the lookups are done as: exec sp_executesql N'SELECT [Active], [CompanyID], [CompanyName], [CompanyShortName], [CompanyTypeID], [HierarchyNodeID] FROM [dbo].[Company] WHERE ([CompanyID]=@P1) AND ([StartDateTime] IS NOT NULL AND [EndDateTime] IS NULL)',N'@P1 int',1 exec sp_executesql N'SELECT [Active], [CompanyID], [CompanyName], [CompanyShortName], [CompanyTypeID], [HierarchyNodeID] FROM [dbo].[Company] WHERE ([CompanyID]=@P1) AND ([StartDateTime] IS NOT NULL AND [EndDateTime] IS NULL)',N'@P1 int',2 exec sp_executesql N'SELECT [Active], [CompanyID], [CompanyName], [CompanyShortName], [CompanyTypeID], [HierarchyNodeID] FROM [dbo].[Company] WHERE ([CompanyID]=@P1) AND ([StartDateTime] IS NOT NULL AND [EndDateTime] IS NULL)',N'@P1 int',3 exec sp_executesql N'SELECT [Active], [CompanyID], [CompanyName], [CompanyShortName], [CompanyTypeID], [HierarchyNodeID] FROM [dbo].[Company] WHERE ([CompanyID]=@P1) AND ([StartDateTime] IS NOT NULL AND [EndDateTime] IS NULL)',N'@P1 int',4 and when analyzed, these statements have the reason "Event does not reference any tables". Huh? Does it not see the FROM dbo.Company??!! What is going on here? So, I have multiple questions: How do I get it to capture the actual statement executing in my trace, not what was submitted in a batch? Are there any best practices to follow for tuning performance related to SSIS packages running against SQL Server 2008?

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  • standard way to perform a clean shutdown with Boost.Asio

    - by Timothy003
    I'm writing a cross-platform server program in C++ using Boost.Asio. Following the HTTP Server example on this page, I'd like to handle a user termination request without using implementation-specific APIs. I've initially attempted to use the standard C signal library, but have been unable to find a design pattern suitable for Asio. The Windows example's design seems to resemble the signal library closest, but there's a race condition where the console ctrl handler could be called after the server object has been destroyed. I'm trying to avoid race conditions that cause undefined behavior as specified by the C++ standard. Is there a standard (correct) way to stop the server? So far: #include <csignal> #include <functional> #include <boost/asio.hpp> using std::signal; using boost::asio::io_service; extern "C" { static void handle_signal(int); } namespace { std::function<void ()> sighandler; } void handle_signal(int) { sighandler(); } int main() { io_service s; sighandler = std::bind(&io_service::stop, &s); auto res = signal(SIGINT, &handle_signal); // race condition? SIGINT raised before I could set ignore back if (res == SIG_IGN) signal(SIGINT, SIG_IGN); res = signal(SIGTERM, &handle_signal); // race condition? SIGTERM raised before I could set ignore back if (res == SIG_IGN) signal(SIGTERM, SIG_IGN); s.run(); // reset signals signal(SIGTERM, SIG_DFL); signal(SIGINT, SIG_DFL); // is it defined whether handle_signal can still be in execution at this // point? sighandler = nullptr; }

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  • How much should the AppDelegate do?

    - by Rudiger
    I'm designing quite a large App and on startup it will create sessions with a few different servers. As they are creating a session which is used across all parts of the app its something I thought would be best in App Delegate. But the problem is I need the session progress to be represented on the screen. I plan to have a UIToolBar at the bottom of the main menu which I don't want to cover with the progress bar but cover the UIView above it.So the way I see it I could do it a few different ways. 1) Have the App Delegate establish the sessions and report the progress to the main menu class so it can represent it in the progress bar (will I have any issues doing this if the sessions are created in a separate thread?), 2) have the App delegate display the main menu (UIView with a bunch of buttons and UIToolBar) and have it track and display the progress (I have never displayed anything in the App Delegate but assume you can do this but its not recommended) or 3) have the App Delegate just push the main menu and have the mainMenu class create the sessions and display the progress bar. 4) I think the other way to do it is to create the sessions in a delegate class and have the delegate set to mainMenu rather than self (AppDelegate), although I've never used anything other then self so not sure if this will work or if I will be able to close the thread (through calling super maybe?) as its running in the AppDelegate rather than the delegate of the class. As I've kinda said before the sessions are being created in a class in a separate thread so it wont lock the UI and I think the best way is the first but am I going to have issues having it running in a separate thread, reporting back to the app delegate and then sending that message to the mainMenu view? I hope that all makes sense, let me know if you need any further clarification. Any information is appreciated Cheers,

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  • Optional Member Objects

    - by David Relihan
    Okay, so you have a load of methods sprinkled around your systems main class. So you do the right thing and refactor by creating a new class and perform move method(s) into a new class. The new class has a single responsibility and all is right with the world again: class Feature { public: Feature(){}; void doSomething(); void doSomething1(); void doSomething2(); }; So now your original class has a member variable of type object: Feature _feature; Which you will call in the main class. Now if you do this many times, you will have many member-objects in your main class. Now these features may or not be required based on configuration so in a way it's costly having all these objects that may or not be needed. Can anyone suggest a way of improving this? At the moment I plan to test in the newly created class if the feature is enabled - so the when a call is made to method I will return if it is not enabled. I could have a pointer to the object and then only call new if feature is enabled - but this means I will have to test before I call a method on it which would be potentially dangerous and not very readable. Would having an auto_ptr to the object improve things: auto_ptr<Feature> feature; Or am I still paying the cost of object invokation even though the object may\or may not be required. BTW - I don't think this is premeature optimisation - I just want to consider the possibilites.

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  • Can you have a Dynamic Data Field which consists of a list of fields?

    - by Telos
    This is a purely theoretical question (at least until I start trying to implement it) but here goes. I wrote a web form a long time ago which has a configurable section for getting information. Basically for some customers there are no fields, for other customers there are up to 20 fields. I got it working by dynamically creating the fields at just the right time in the page lifecycle and going through a lot of headaches. 2 years later, I need to make some pretty big updates to this web form and there are some nifty new technologies. I've worked with ASP.NET Dynamic Data just a bit and, well, I half-crazed plan just occurred to me: The Ticket object has a one-to-many relationship to ExtendedField, we'll call that relationship Fields for brevity. Using that, the idea would be to create a FieldTemplate that dynamically generated the list of fields and displayed it. The big questions here would probably be: 1) Can a single field template resolve to multiple web controls without breaking things? 2) Can dynamic data handle updating/inserting multiple rows in such a fashion? 3) There was a third question I had a few minutes ago, but coworkers interrupted me and I forgot. So now the third question is: what is the third question? So basically, does this sound like it could work or am I missing a better/more obvious solution?

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  • Need simple advice for graph solving problem

    - by sap
    Hi there, a collegue of mine proposed to me an exercise from an online judge website, which is basically a graph solving problem of an evacuation plan on a small town. i dont need the answer (nor do i want it) i just need an advice on which is the best approach to solving it since im kinda new to these kind of problems. the problem consists of town buildings with workers and fallout shelters in case of a nuclear attack. i have to build an algorithm that will assign the workers of each building to one or more fallout shelters but in a way that some shelters wont became too overcrowded while others remain almost empty (else i would just make the workers go to the nearest one). the problem is this: http://acm.timus.ru/problem.aspx?space=1&num=1237 in case its offline heres the google cached version of it: http://webcache.googleusercontent.com/search?q=cache:t2EPCzezs7AJ:acm.timus.ru/problem.aspx%3Fspace%3D1%26num%3D1237+vladimir+kotov+evacuation+problem&cd=1&hl=pt-PT&ct=clnk&gl=pt what i've done so far is for each building get the nearest shelter and move the number of workers from that build equal to the shelter capacity. then move to the next building. but sometimes the number of workers is greater than the shelter capacity, in that case after i iterate through every building, ill just iterate then again apllying the same algorithm until every building has 0 workers in it, problem is this is hardly the best way to solve it. any tip is welcome, please dont feel like im asking for the answer, i just want an advice in the right direction of solving it. thanks in advance.

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  • Flex/Flash 4 ExternalInterface.call - trying to get a string from HTML to Actionscript.

    - by Setori
    Dear all, I need to obtain a string from HTML and put it into Actionscript. the actionscript: import flash.external.ExternalInterface; protected function getUserName():void{ var isAvailable:Boolean = ExternalInterface.available; var findUserName:String = "findUserName"; if(isAvailable){ var foundUserName:String = ExternalInterface.call(findUserName); Alert.show(foundUserName);}} the javascript: function findUserName() { var label = document.getElementById("username-label"); if(label.value != ""){ alert("the name in the box is: " + label.value); return label.value;} else return "nothing in the textbox";}} the JSP: <%IUserSession userSession = SessionManager.getSession();%> <logic:notEmpty name="userSession"> <logic:notEqual value="anonymous" name="userSession" property="userLoginId"> <td align="right" width="10%" > <input id="username-label" type="text" value="<bean:write name="userSession" property="userLoginId"/>" /> </td> </logic:notEqual> </logic:notEmpty> the rendered HTML: <td align="right" width="10%"> <input id="username-label" type="text" value="a-valid-username" /> </td> when the javascript execution hits var label = document.getElementById("username-label"); a null is returned and crashes, no alert shows no error message is shown. firfox 3.5 windows, container is Tomcat. Please advise, and thank you in advance.

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