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• Reverse geocode street name and city as text

  - by Taylor Satula

  Hello, I have been having some trouble finding a good way to output just the street name and city as text (Infinite Loop, Cupertino shown here) that can be displayed in my iPhone app. This needs to be able to dynamically change as you change streets and city. I don't have the slightest idea of how to do this, I hope someone can help. I have attached a very rough image of what I am trying to acheave. I have found this (http://code.google.com/apis/maps/documentation/javascript/services.html#Geocoding) for google maps about how to reverse geocode using javascript, but what I do not understand is how this would be done in a iPhone development setting. I work in web design and I see how it would be done in HTML but I am very new to iPhone development and don't have the slightest clue of how it would be done here. If someone could spell out how to do this I would be extremely grateful. I cannot seem to find what I am looking for by searching Google. Reference picture: http://www.threepixeldrift.com/images/deep-storage/reversegeocodeiphoneapp.jpg

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• Can I force the auto-generated Linq-to-SQL classes to use an OUTER JOIN?

  - by Gary McGill

  Let's say I have an Order table which has a FirstSalesPersonId field and a SecondSalesPersonId field. Both of these are foreign keys that reference the SalesPerson table. For any given order, either one or two salespersons may be credited with the order. In other words, FirstSalesPersonId can never be NULL, but SecondSalesPersonId can be NULL. When I drop my Order and SalesPerson tables onto the "Linq to SQL Classes" design surface, the class builder spots the two FK relationships from the Order table to the SalesPerson table, and so the generated Order class has a SalesPerson field and a SalesPerson1 field (which I can rename to SalesPerson1 and SalesPerson2 to avoid confusion). Because I always want to have the salesperson data available whenever I process an order, I am using DataLoadOptions.LoadWith to specify that the two salesperson fields are populated when the order instance is populated, as follows: dataLoadOptions.LoadWith<Order>(o => o.SalesPerson1); dataLoadOptions.LoadWith<Order>(o => o.SalesPerson2); The problem I'm having is that Linq to SQL is using something like the following SQL to load an order: SELECT ... FROM Order O INNER JOIN SalesPerson SP1 ON SP1.salesPersonId = O.firstSalesPersonId INNER JOIN SalesPerson SP2 ON SP2.salesPersonId = O.secondSalesPersonId This would make sense if there were always two salesperson records, but because there is sometimes no second salesperson (secondSalesPersonId is NULL), the INNER JOIN causes the query to return no records in that case. What I effectively want here is to change the second INNER JOIN into a LEFT OUTER JOIN. Is there a way to do that through the UI for the class generator? If not, how else can I achieve this? (Note that because I'm using the generated classes almost exclusively, I'd rather not have something tacked on the side for this one case if I can avoid it).

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• Java plugin framework choice

  - by Marcus

  We're trying to determine how to implement a simple plugin framework for a service we are implementing that allows different types of calculators to be "plugged-in". After reading a number of posts about Java plugin frameworks, it seems like the most common options are: OSGI "Rolling your own" plugin framework The Java Plugin Framework (JPF) The Java Simple Plugin Framework (JSPF) OSGI seems to be more than we need. "Rolling your own" is ok but it would be nice to reuse a common library. So we're down to the JPF and JSPF. JPF seems to not be in active development right now. JSPF seems very simple and really all we need. However I haven't heard much about it. I've only seen one post on StackOverflow about it. Does anyone else have any experience with JSPF? Or any other comments on this design choice? Update: There isn't necessarily a correct answer to this.. however we're going to go with Pavol's idea as we need just a really, really simple solution. Thanks EoH for the nice guide.

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• PHP Exceptions in Classes

  - by mike condiff

  I'm writing a web application (PHP) for my friend and have decided to use my limited OOP training from Java. My question is what is the best way to note in my class/application that specific critical things failed without actually breaking my page. Currently my problem is I have an Object "SummerCamper" which takes a camper_id as it's argument to load all of the necessary data into the object from the database. Say someone specifies a camper_id in the querystring that does not exist, I pass it to my objects constructor and the load fails. Currently I don't see a way for me to just return false from the constructor. I have read I could possibly do this with Exceptions, throwing an exception if no records are found in the database or if some sort of validation fails on input of the camper_id from the application etc. However, I have not really found a great way to alert my program that the Object Load has failed. I tried returning false from within the CATCH but the Object still persists in my php page. I do understand I could put a variable $is_valid = false if the load fails and then check the Object using a get method but I think there may be better ways. What is the best way of achieving the essential termination of an object if a load fails? Should I load data into the object from outside the constructor? Is there some osrt of design pattern that I should look into? Any help would be appreciated.

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• Database structure for ecommerce site

  - by imanc

  Hey Guys, I have been tasked with designing an ecommerce solution. The aspect that is causing me the most problems is the database. Currently the site consists of 10+ country based shops each with their own database (all residing on the same mysql instance). For the new site I'd rather all these shop databases be merged into one database so that all tables (products, orders, customers etc.) have a shop_id field. From a programming perspective this seems to make the most sense as we won't have to manage data across multiple databases. Currently the entire site generates about 120k orders a year, but is experiencing fairly heavy growth and we need to design a solution that will scale. In 5 years there may be more than a million orders per year and a database that contains 5 years order history (archiving maybe a solution here). The question is - do we use a single database, or do we keep the database-per-shop structure? I am currently trying to find supporting evidence for either avenue. The company I am designing the solution for prefer the per-shop database structure because they believe it will allow the sites to scale. But my argument is that the shop's database probably won't get that busy over the next few years that they exceed the capacity of a mysql database and a "no expenses spared" hardware set-up. I am wondering if anyone has any advice either way? Does anyone have experience with websites / ecommerce sites that have tables containing millions of records? I know there is probably not a clear answer here, but at what stage do we have too many records or too large table files to have a fast loading site? Also, if anyone has any advice on sources of information - books, websites, etc. where I can do further research, it would be highly appreciated! Cheers, imanc

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• NoSQL for filesystem storage organization and replication?

  - by wheaties

  We've been discussing design of a data warehouse strategy within our group for meeting testing, reproducibility, and data syncing requirements. One of the suggested ideas is to adapt a NoSQL approach using an existing tool rather than try to re-implement a whole lot of the same on a file system. I don't know if a NoSQL approach is even the best approach to what we're trying to accomplish but perhaps if I describe what we need/want you all can help. Most of our files are large, 50+ Gig in size, held in a proprietary, third-party format. We need to be able to access each file by a name/date/source/time/artifact combination. Essentially a key-value pair style look-up. When we query for a file, we don't want to have to load all of it into memory. They're really too large and would swamp our server. We want to be able to somehow get a reference to the file and then use a proprietary, third-party API to ingest portions of it. We want to easily add, remove, and export files from storage. We'd like to set up automatic file replication between two servers (we can write a script for this.) That is, sync the contents of one server with another. We don't need a distributed system where it only appears as if we have one server. We'd like complete replication. We also have other smaller files that have a tree type relationship with the Big files. One file's content will point to the next and so on, and so on. It's not a "spoked wheel," it's a full blown tree. We'd prefer a Python, C or C++ API to work with a system like this but most of us are experienced with a variety of languages. We don't mind as long as it works, gets the job done, and saves us time. What you think? Is there something out there like this?

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• How can I find out if the MainActivity is being paused from my Java class?

  - by quinestor

  I am using motion sensor detection in my application. My design is this: a class gets the sensor services references from the main activity and then it implements SensorEventListener. That is, the MainActivity does not listen for sensor event changes: public void onCreate(Bundle savedInstanceState) { // ... code mSensorManager = (SensorManager) getSystemService(Context.SENSOR_SERVICE); mAccelerometer = mSensorManager.getDefaultSensor(Sensor.TYPE_ACCELEROMETER); // The following is my java class, it does not extends any android fragment/activty mShakeUtil = new ShakeUtil(mSensorManager,mAccelerometer,this); // ..more code.. } I can't redesign ShakeUtil so it is a fragment nor activity, unfortunately. Now to illustrate the problem consider: MainActivity is on its way to be destroyed/paused. I.e screen rotation ShakeUtil's onSensorChanged(SensorEvent event) gets called in the process.. One of the things that happen inside onSensorChanged is a dialog interaction, which gives the error: java.lang.IllegalStateException: Can not perform this action after onSaveInstanceState When the previous happens between MainActivity's onSaveInstanceState and onPause. I know this can be prevented if I successfully detect that MainActivity is being pause in ShakeUtil. How can I detect that MainActivity is being paused or onSaveInstanceState was called from ShakeUtil? Alternatively, how can I avoid this issue without making Shakeutil extend activity? So far I have tried with flag variables but that isn't good enough, I guess these are not atomic operations. I tried using Activity's isChangingConfigurations(), but I get an undocummented "NoSuchMethodFound" error.. I am unregistering the sensors by calling ShakeUtil when onPause in main ACtivity

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• How to use custom UITableViewCell from Interface Builder?

  - by Krumelur

  I want to be able to design my own UITableViewCell in IB. But I keep getting a null ref exception when trying to access the label I defined in IB. Here's what I'm doing: In Interface Builder: I removed the "View" and added a UITableViewCell instead. Changed the class of the UITableViewCell to "TestCellView". Added a UILabel to the cell. Added an outlet "oLblText" to TestCellView and connected the UILabel to it. Changed the identifier of the class to "TestCellView". Implement TestCellView.xib.cs public partial class TestCellView : UITableViewCell { public TestCellView(string sKey) : base(UITableViewCellStyle.Default, sKey) { } public TestCellView(IntPtr oHandle) : base(oHandle) { } public string TestText { get { return this.oLblText.Text; } set { // HERE I get the null ref exception! this.oLblText.Text = value; } } } ** The TestCellView.designer.cs** [MonoTouch.Foundation.Register("TestCellView")] public partial class TestCellView { private MonoTouch.UIKit.UILabel __mt_oLblText; #pragma warning disable 0169 [MonoTouch.Foundation.Connect("oLblText")] private MonoTouch.UIKit.UILabel oLblText { get { this.__mt_oLblText = ((MonoTouch.UIKit.UILabel)(this.GetNativeField("oLblText"))); return this.__mt_oLblText; } set { this.__mt_oLblText = value; this.SetNativeField("oLblText", value); } } } In my table's source: public override UITableViewCell GetCell (UITableView tableView, NSIndexPath indexPath) { TestCellView oCell = (TestCellView)tableView.DequeueReusableCell("myCell"); if(oCell == null) { // I suppose this is wrong but how to do it correctly? // this == my UITableViewSource. NSBundle.MainBundle.LoadNib("TestCellView", this, null); oCell = new TestCellView("myCell"); } oCell.TestText = "Cell " + indexPath.Row; return oCell; } Please note that I do NOT want a solution that involves a UIViewController for every cell. I have seen a couple of examples on the web doing this. I just think it is total overkill. What am I doing wrong?

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• Users Hierarchy Logic

  - by user342944

  Hi guys, I am writing a user security module using SQLServer 2008 so threfore need to design a database accordingly. Formally I had Userinfo table with UserID, Username and ParentID to build a recursion and populated tree to represent hierarchy but now I have following criteria which I need to develop. I have now USERS, ADMINISTRATORS and GROUPS. Each node in the user hierarchy is either a user, administrator or group. User Someone who has login access to my application Administrator A user who may also manage all their child user accounts (and their children etc) This may include creating new users and assigning permissions to those users. There is no limit to the number of administrators in user structure. The higher up in the hierarchy that I go administrators have more child accounts to manage which include other child administrators. Group A user account can be designated as a group. This will be an account which is used to group one or more users together so that they can be manage as a unit. But no one can login to my application using a group account. This is how I want to create structure Super Administrator administrator ------------------------------------------------------------- | | | Manager A Manager B Manager C (adminstrator) (administrator) (administrator) | ----------------------------------------- | | | Employee A Employee B Sales Employees (User) (User) (Group) | ------------------------ | | | Emp C Emp D Emp E (User) (User) (User) Now how to build the table structure to achieve this. Do I need to create Users table alongwith Group table or what? Please guide I would really appreciate.

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• DotNetOpeId - Using OpenIdButton for Google Apps

  - by JediPotPie

  I am an ASP.NET newbie and I am trying to design an OpenID/SSO system for an internal web application. The web application is pretty simple and the authentication is currently being managed by a database with usernames and passwords. I want to replace the existing accounts stored in the database with Google Apps accounts. I have downloaded the latest DotNetOpenAuth-3.4.3.10103 package and got the OpenIdRelyingPartyWebForms sample up and running on IIS. I have built my own login page using just a OpenIdButton object that points to a development Google domain. The button seems to work fine in FireFox, at least it is forwarding me to the Google Apps login, but nothing happens when I load the same page in IE. When I click the Google button, nothing happens, zip. The same is true for the Yahoo button in the login.aspx page given in the sample. Here is the .aspx code I am using... <rp:OpenIdButton runat="server" ImageUrl="http://www.google.com/accounts/google_transparent.gif" Text="Login with Google!" ID="googleLoginButton" Identifier="https://www.google.com/accounts/o8/site-xrds?hd=dev.connexcloud.com" />

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• ContentPresenter within ControlTemplate cannot change attached dependency property

  - by happyclicker

  Why does the following simplified code not set the font-size of the TextBlock to 50? <Window.Resources> <ControlTemplate TargetType="ContentControl" x:Key="Test"> <ContentPresenter TextBlock.FontSize="50" /> </ControlTemplate> </Window.Resources> <Grid> <ContentControl Template="{StaticResource Test}"> <TextBlock>Test should be rendered big</TextBlock> </ContentControl> </Grid> If I change the value of the FontSize property, visual studio shows me the text in the size I want. After compiling or executing the app, the size of the textblock is always reset to its default size. I have also tested various versions with styles and embedded resources but I end always in the situation that I cannot set attached dp's from within a ControlTemplate that contains a ContentPresenter. Is this by design?

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• What does it mean for an OS to "execute within user processes"? Do any modern OS's use that approach

  - by Chris Cooper

  I have recently become interested in operating system, and a friend of mine lent me a book called Operating Systems: Internals and Design Principles (I have the third edition), published in 1998. It's been a very interesting book so far, but I have come to the part dealing with process control, and it's using UNIX System V as one of its examples of an operating system that executes within user processes. This concept has struck me as a little strange. First of all, does this mean that OS instructions and data are stored in each user of the processes? Probably not, because that would be an absurdly redundant scheme. But if not, then what does it mean to "execute within" a user process? Do any modern operating systems use this approach? It seems much more logical to have the operating system execute as its own process, or even independently of all processes, if you're short on memory. All the inter-accessiblilty of process data required for this layout seems to greatly complicate things. (But maybe that's just because I don't quite get the concept ;D) Here is what the book says: "Execution within User Processes: An alternative that is common with operation systems on smaller machines is to execute virtually all operating system software in the context of a user process. ... "

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• Using a CMS with an external database

  - by George Reith

  I am looking at building an external site with a CMS, probably Drupal or ExpressionEngine. The problem is that our company already has a membership database that is designed to work with our existing enterprise software. Migrating data from the database manually is not an option as modifications and new data must be accessible in real-time. Because the design of the external database will differ from the CMS's own I have decided the best way forward is to use two databases and force the CMS to use the external to read user information (cannot write to) and a local for everything else the CMS needs to do (read + write). Is this feasible with these Drupal or ExpressionEngine? Ideally I need to be able to use hooks as I do not wan't to modify core CMS files. Sifting through the docs I am not able to find what I would hook into for ether CMS. (Note: I know it is possible, but I want to know if it's feasible). Finally if there is a better way of handling this situation please also chime in. Perhaps there is something at the database level to reference a field or table in an external database? I'm clutching at straws someone can point me in the right direction I'm sure.

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• Scheduler with Asp Mvc

  - by Samuel

  Hi, I want to use a Scheduler like Telerik Scheduler in my Mvc project. The problem is that the Scheduler is a Asp.Net WebForm control. For this reason, I must create a WebForm page in my Mvc project to put the Scheduler control. When I show the page, it work fine to render the layout of the control but if I try to interact with it; click for change date, change to day view to week view, the control don't change. I know that postback doesn't work in mvc project but does it work in a WebForm page in a Mvc project? If it doesn't work, it is the reason why when I try to interact with the control, the control don't respond. I think it's because the postback don't work and the Scheduler use 100 % Databinding where when I change date, the postback don't contain any data that I have changed and for this reason, the control can't change is layout. Have you any ideas about postback with WebForm in mvc project? What type of design can I adopt? (Two differents projets: One for my Scheduler with WebForm and another for all the rest of my website in Mvc project) Any other control easily to use with Scheduler? Tips and tricks when needing both WebForm control and Mvc control in Mvc project? Thank you very much.

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• Why is BorderLayout calling setSize() and setBounds()?

  - by ags

  I'm trying to get my head around proper use of the different LayoutManagers to make my GUI design skills more efficient and effective. For me, that usually requires a detailed understanding of what is going on under the hood. I've found some good discussion of the interaction and consequences of a Container using BorderLayout containing a Container using FlowLayout. I understand it for the most part, but wanted to confirm my mental model and to do so I am looking at the code for BorderLayout. In the code snippet below taken from BorderLayout.layoutContainer(), note the calls to the child Component's setSize() method followed by setBounds(). Looking at the source for these methods of Component, setSize() actually calls setBounds() with the current values for Component.x and Component.y. Why is this done (and not entirely redudant?) Doesn't the setBounds() call completely overwrite the results of the setSize() call? if ((c=getChild(NORTH,ltr)) != null) { c.setSize(right - left, c.height); Dimension d = c.getPreferredSize(); c.setBounds(left, top, right - left, d.height); top += d.height + vgap; } I'm also tring to understand where/when the child Component's size is initially set (before the LayoutManager.layoutContainer() method is called). Finally, this post itself raises a "meta-question": in a situation like this, where the source is available elsewhere, is the accepteed protocol to include the entire method? Or some other way to make it easier for folks to participate in the thread? Thanks.

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• MySQL " identify storage engine statement"

  - by sammysmall

  This IS NOT a Homework question! While building my current student database project I realized that I may want to identify comprehensive information about a database design in the future. More-so if I am fortunate enough to get a job in this field and were handed a database project how could I break down certain elements for identification... In all of my previous designs I have been using MySQL Community Server (GPL) 5.1.42, I thought (duh) that I was using the MyISAM based on most of my text-book instruction and MySQL 5.0 Reference Manual :: 13 Storage Engines :: 13.1 The MyISAM Storage Engine I determined that this was in fact incorrect for this version and the use of "SHOW ENGINES" at the console... No problem, figured out why they have "versions" the need to pay attention to what version is being used, and the need for a means to determine what I am about to mess up "if" I do not pay attention to detail... Q1. Specifically what statement will identify the version used by someone elses initial database creation? (since I created my own databases I know what version I used) Q2. Specifically what statement will identify the storage engine that the developer used when creating the database. (I specified a particular database in my collection then tried SHOW Engine, did not work, then tried to just get the metadata from one table in that database: mysql SELECT duck_cust, table_type, engine - FROM INFORMATION_SCHEMA.tables - WHERE table_schema = 'tp' - ORDER BY table_type ASC, table_name DESC; as this was not really what I wanted (and did not work) I am looking for some direction from the pros... Q3. (If you really have the inclination to continue helping) If I were to access a database from an earlier/later "version" are there backward/forward compatibility issues for maintaining/updating data between versions? Please and Thank you in advance for your time and efforts! sammysmall

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• Double hashing passwords - client & server

  - by J. Stoever

  Hey, first, let me say, I'm not asking about things like md5(md5(..., there are already topics about it. My question is this: We allow our clients to store their passwords locally. Naturally, we don't want them stored in plan text, so we hmac them locally, before storing and/or sending. Now, this is fine, but if this is all we did, then the server would have the stored hmac, and since the client only needs to send the hmac, not the plain text password, an attacker could use the stored hashes from the server to access anyone's account (in the catastrophic scenario where someone would get such an access to the database, of course). So, our idea was to encode the password on the client once via hmac, send it to the server, and there encode it a second time via hmac and match it against the stored, two times hmac'ed password. This would ensure that: The client can store the password locally without having to store it as plain text The client can send the password without having to worry (too much) about other network parties The server can store the password without having to worry about someone stealing it from the server and using it to log in. Naturally, all the other things (strong passwords, double salt, etc) apply as well, but aren't really relevant to the question. The actual question is: does this sound like a solid security design ? Did we overlook any flaws with doing things this way ? Is there maybe a security pattern for something like this ?

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• Pop-up and font colour based problems in a form which is designed in Share Point.

  - by ephieste

  I am designing a system in Share Point via Share Point Designer. We have a form in my Share Point site. Users have to fill some fields in the form and send it to the approval committee. We cannot upload anything to the servers. The design is site based. Our problems are: 1- I want to add small (?) icons for the descriptions of that field. When the user click on the (?) icon for "brief description" field a pop-up or another window will be opened and perhaps it will say: Enter a description of the requested thing. Be as specific as possible. 2- I want to change the font colors of the fields in the form. The share point brings them black as default. Such as I want to see the "Brief description:" and "Status:" as purple instead of black. Brief description: ..... Status: ..... 3- I want to add an agreement pop-up to the new form which will be open just after clicking "send" button in the form. The pop up will say: "Are you sure that you read the procedure" . The user has to click "Yes" to continue sending the form. Otherwise It will return to previous screen again. I would be glad if you kindly help me.

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• How big can I make an Android application's canvas in terms of pixels?

  - by user279112

  I've determined an estimate of the size of my Android emulator's screen in pixels, although I think its resolution can be changed to other numbers. Quite frankly though that doesn't eliminate the general problem of not knowing how many pixels on each axis I have to work with on my Android applications in general. The main problem I'm trying to solve is this: How do I make sure I don't use a faulty resolution on Android applications if I want to keep things' sizes constant (so that if the application screen shrinks, for instances, objects will still show up just as big - there just won't be as many of them being shown) if I wish to do this with a single universal resolution for each program? Failing that, how do I make sure everything's alright if I try to do everything the same way with maybe a few different pre-set resolutions? Mainly it seems like a relevant question that must be answered before I can come across a complete answer for the general problem is how big can I always make my application in pixels, NOT regarding if and when a user resizes the application's screen to something smaller than the maximum size permitted by the phone and its operating system. I really want to try to keep this simple. If I were doing this for a modern desktop, for instance, I know that if I design the application with a 800x600 canvas, the user can still shrink the application to the point they're not doing themselves any favors, but at least I can basically count on it working right and not being too big for the monitor or something. Is there such a magic resolution for Android, assuming that I'm designing for API levels 3+ (Android 1.5+)? Thanks

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• Looking for Opinions and Sugestions on my Website. (General Question)

  - by MrEnder

  I am looking for general opinions and suggestions about the site in whole. Its ok I don't mind hearing where I went wrong on anything. I'm still learning. All tips and pointers on any subject relating are highly welcome. If you are going to make a suggestion and post a snippet or code please explain how it works in detail. The site was design as a interface to display the labs I have to do in my college (the labs are all basic things that I'm way beyond). So I decided to take it all to the next level with this. The link is http://opentech.durhamcollege.ca/~intn2201/brittains/labs/ It is 100% designed by me with the exception of the icons. (I could not think of anything better to draw) There is no specific area of the site I want suggestions or opinions on this is a general question. You may answer about the site in whole or an area of the coding just please specify. If you have any questions related to my site or code you may ask them as well. Thank you for your time and any comments Shelby

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• Sharing a COM port over TCP

  - by guinness

  What would be a simple design pattern for sharing a COM port over TCP to multiple clients? For example, a local GPS device that could transmit co-ordinates to remote hosts in realtime. So I need a program that would open the serial port and accept multiple TCP connections like: class Program { public static void Main(string[] args) { SerialPort sp = new SerialPort("COM4", 19200, Parity.None, 8, StopBits.One); Socket srv = new Socket(AddressFamily.InterNetwork, SocketType.Stream, ProtocolType.Tcp); srv.Bind(new IPEndPoint(IPAddress.Any, 8000)); srv.Listen(20); while (true) { Socket soc = srv.Accept(); new Connection(soc); } } } I would then need a class to handle the communication between connected clients, allowing them all to see the data and keeping it synchronized so client commands are received in sequence: class Connection { static object lck = new object(); static List<Connection> cons = new List<Connection>(); public Socket socket; public StreamReader reader; public StreamWriter writer; public Connection(Socket soc) { this.socket = soc; this.reader = new StreamReader(new NetworkStream(soc, false)); this.writer = new StreamWriter(new NetworkStream(soc, true)); new Thread(ClientLoop).Start(); } void ClientLoop() { lock (lck) { connections.Add(this); } while (true) { lock (lck) { string line = reader.ReadLine(); if (String.IsNullOrEmpty(line)) break; foreach (Connection con in cons) con.writer.WriteLine(line); } } lock (lck) { cons.Remove(this); socket.Close(); } } } The problem I'm struggling to resolve is how to facilitate communication between the SerialPort instance and the threads. I'm not certain that the above code is the best way forward, so does anybody have another solution (the simpler the better)?

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• How to get at specific HTML elements of a document using C# and Hide them/Show them etc.

  - by LaserBeak

  Basically I want to load a HTML document and using controls such as multiple check boxes which will be programmed to hide, delete or show HTML elements with certain ID's. So I am thinking I would have to set an inline CSS property for visibility to: false on the ones I want to hide or delete them altogether when necessary. I need this so I don't have to edit my Ebay HTML templates in dreamweaver all the time, where I usually have to scroll around messy code and manually delete or add tags and their respective content. Whereas I just want to create one master template in dreamweaver which has all the variations that my products have, since they are all of the same genre with slight changes here and there and I just need to enable and disable the visibility of these variants as required and copy + paste the final html. I haven's used Windows Forms before, but tried doing this in WebForms which I do know a bit. I am able to get the result that I want by wrapping any HTML elements in a <asp:PlaceHolder></asp:PlaceHolder> and just setting that place holders visibility to false after the associated checkbox is checked and a postback occurs, finally I add a checkbox/button control that removes all the checkboxes, including itself etc for final html. But this method seems just like too much pain in the ass as I have to add the placeholder tags around everything that I need control over as ordinary html elements do not run at server, also webforms injects a bunch of Javascript and ViewState data so I don't have clean HTML which I can just copy after viewing the page source. Any tips/code that you can suggest to achieve the desired effect with the least changes required to existing HTML documents? Ideally I would want to load the HTML document in, have a live design preview of it and underneath have a bunch of well labelled checkboxes programmed to hide, delete or show elements with certain ID's. Thanks...

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• How do virtual destructors work?

  - by Prabhu

  Few hours back I was fiddling with a Memory Leak issue and it turned out that I really got some basic stuff about virtual destructors wrong! Let me put explain my class design. class Base { virtual push_elements() {} }; class Derived:public Base { vector<int> x; public: void push_elements(){ for(int i=0;i <5;i++) x.push_back(i); } }; void main() { Base* b = new Derived(); b->push_elements(); delete b; } The bounds checker tool reported a memory leak in the derived class vector. And I figured out that the destructor is not virtual and the derived class destructor is not called. And it surprisingly got fixed when I made the destructor virtual. Isn't the vector deallocated automatically even if the derived class destructor is not called? Is that a quirk in BoundsChecker tool or is my understanding of virtual destructor wrong?

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• Scientific Algorithms that can produce imagery, pseudocode perhaps?

  - by Ross

  Hello, I have a client who are based in the field of mathematics. We are developing, amongst other things, a website. I like to create a mock-up of a drawing tool that an produce some imagery in the background based on some scientific algorithms. The intention being that the may client, later, may create there own. (They use emacs for everything, great client.) I'm look for an answer of where or what to go looking for. Not code specific, pseudocode even, as we can adapt and have not yet settled on a platform. I'm afraid my mathematic stops at the power of two and some trigonometry. Appreciated if they're are any mathematics related students/academics how could enlighten me? What to search for will be accepted? Edit: To summarise/clarify, I want to draw pretty pictures (the design perspective). I want them to have some context (i.e. not just for the sake of pretty images but have some explanation available). In essence I would to create a rendering engine which we can draw the images and we set the style parameters: line, colour, etc... But to pursue this option I want to experiment myself. Thanks Ross

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• How to check whether user is login in web application?

  - by Morgan Cheng

  I want to learn the whole details of web application authentication. So, I decided to write a CodeIgniter authentication library from scratch. Now, I have to make design decision about how to determine whether one user is login. Basically, after user input username & password pair. A cookie is set for this session, following navigations in the web application will not require username & password. The server side will check whether the session cookie is valid to determine whether current user is login. The question is: how to determine whether cookie is valid cookie issued from server side? I can image the most simple way is to have the cookie value stored in session status as well. For each HTTP request, compare the value from cookie and the value from server session. (Since CodeIgniter session library store session variables in cookies, it is not applicable without some tweak.) This method requires storage in server side. For huge web application that is deployed in multiple datacenters. It is possible that user input username & password when browsing in one datacenter, while he/she access the web application in another datacenter later. The expected behavior is that user just input username & password once. As a result, all datacenters should be able to access the session status. That is possible not applicable even the session status is stored in external storage such as database. I tried Google. I login Google with Asian proxy which is supposed to direct me to datacenters in Asian. Then I switch to North American proxy which should direct me to datacenters in North America. It recognize my login without asking username and password again. So, is there any way to determine whether user is login without server side session status?

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