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  • Is the recent trend toward widescreen (16:9) computer monitors a plus or minus for programmers?

    - by DanM
    It's almost gotten to the point where you can't buy a conventional (4:3) monitor anymore. Pretty much everything is widescreen. This is fine for watching movies or TV, but is it good or bad for programming? My initial thoughts on the issue are that widescreens are a net negative for programmers. Here are some of the disadvantages I see: Poor space utiliziation One disadvantage of widescreens you can't argue with is that they offer poor space utilization for the amount of total pixels you get. For example, my Thinkpad, which I bought just before the widescreen craze, has a 15" monitor with a native resolution of 1600 x 1200. The newer 15.4" Thinkpads run at most 1680 x 1050. So (if you do the math) you get fewer pixels in a wider (but not shorter) package. With desktop monitors, you pay a price in terms of desk space used. Two 1680 x 1050 monitors will simply take up more of your desk than two 1600 x 1200 monitors (assuming equal dot pitch). More scrolling If you compare a 1680 x 1050 monitor to a 1600 x 1200 monitor, you get 80 extra pixels of width but 150 fewer pixels of height. The height reduction means you lose approximately 11 lines of code. That's less you can see on the screen at one time and more scrolling you have to do. This harms productivity, maybe not dramatically, but insidiously. Less room for wide panels Widescreens also mean you lose space for wide but short panels common in programming environments. If you use Visual Studio, for example, your code window will be that much shorter when viewing the Find Results, Task List, or Error List (all of which I use frequently). This isn't to say the 80 pixels of extra width you get with widescreen would never be useful, but I tend to keep my lines of code short, so seeing more lines would be more valuable to me than seeing fewer, longer lines. What do you think? Do you agree/disagree? Are you now using one or more widescreen monitors for development? What resolution are you running on each? Do you ever miss the height of the traditional 4:3 monitor? Would you complain if your monitors were one inch narrower but two inches taller?

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  • Need help accessing PHP DOM elements

    - by Michael Pasqualone
    Hey guys, I have the following HTML structure that I am trying to pull information from: // Product 1 <div class="productName"> <span id="product-name-1">Product Name 1</span> </div> <div class="productDetail"> <span class="warehouse">Warehouse 1, ACT</span> <span class="quantityInStock">25</span> </div> // Product 2 <div class="productName"> <span id="product-name-2">Product Name 2</span> </div> <div class="productDetail"> <span class="warehouse">Warehouse 2, ACT</span> <span class="quantityInStock">25</span> </div> … // Product X <div class="productName"> <span id="product-name-X">Product Name X</span> </div> <div class="productDetail"> <span class="warehouse">Warehouse X, ACT</span> <span class="quantityInStock">25</span> </div> I don't have control of the source html and as you'll see productName and it's accompanying productDetail are not contained within a common element. Now, I am using the following php code to try and parse the page. $html = new DOMDocument(); $html->loadHtmlFile('product_test.html'); $xPath = new DOMXPath($html); $domQuery = '//div[@class="productName"]|//div[@class="productDetail"]'; $entries = $xPath->query($domQuery); foreach ($entries as $entry) { echo "Detail: " . $entry->nodeValue) . "<br />\n"; } Which prints the following: Detail: Product Name 1 Detail: Warehouse 1, ACT Detail: 25 Detail: Product Name 2 Detail: Warehouse 2, ACT Detail: 25 Detail: Product Name X Detail: Warehouse X, ACT Detail: 25 Now, this is close to what I want. But I need to do some processing on each Product, Warehouse and Quantity stock and can't figure out how to parse it out into separate product groups. The final output I am after is something like: Product 1: Name: Product Name 1 Warehouse: Warehouse 1, ACT Stock: 25 Product 2: Name: Product Name 2 Warehouse: Warehouse 2, ACT Stock: 25 I can't just figure it out, and I can't wrap my head around this DOM stuff as the elements don't quite work the same as a standard array. If anyone can assist, or point me in the right direction I will be ever appreciative.

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  • What are the weaknesses of this user authentication method?

    - by byronh
    I'm developing my own PHP framework. It seems all the security articles I have read use vastly different methods for user authentication than I do so I could use some help in finding security holes. Some information that might be useful before I start. I use mod_rewrite for my MVC url's. Passwords are sha1 and md5 encrypted with 24 character salt unique to each user. mysql_real_escape_string and/or variable typecasting on everything going in, and htmlspecialchars on everything coming out. Step-by step process: Top of every page: session_start(); session_regenerate_id(); If user logs in via login form, generate new random token to put in user's MySQL row. Hash is generated based on user's salt (from when they first registered) and the new token. Store the hash and plaintext username in session variables, and duplicate in cookies if 'Remember me' is checked. On every page, check for cookies. If cookies set, copy their values into session variables. Then compare $_SESSION['name'] and $_SESSION['hash'] against MySQL database. Destroy all cookies and session variables if they don't match so they have to log in again. If login is valid, some of the user's information from the MySQL database is stored in an array for easy access. So far, I've assumed that this array is clean so when limiting user access I refer to user.rank and deny access if it's below what's required for that page. I've tried to test all the common attacks like XSS and CSRF, but maybe I'm just not good enough at hacking my own site! My system seems way too simple for it to actually be secure (the security code is only 100 lines long). What am I missing? I've also spent alot of time searching for the vulnerabilities with mysql_real_escape string but I haven't found any information that is up-to-date (everything is from several years ago at least and has apparently been fixed). All I know is that the problem was something to do with encoding. If that problem still exists today, how can I avoid it? Any help will be much appreciated.

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  • How to remove the explicit dependencies to other projects' libraries in Eclipse launch configuration

    - by euluis
    In Eclipse it is possible to create launch configurations in a project, specifying the runtime dependencies from another project. A problem I found was that if you have a multiple project workspace, being possible that each project has its own libraries, it is easy to add explicit dependencies in a secondary project to libraries that are of another project and therefore subject to change. An example of this problem follows: proj1 +-- src +-- lib +-- jar1-v1.0.jar +-- jar2-v1.0.jar proj2 +-- src +-- proj2-tests.launch I don't have a dependency from the code in proj2/src to the libraries in proj1/lib. Nevertheless, I do have a dependency from proj2/src to proj1/src, although since there is an internal dependency in the code in proj1/src to its libraries jar1-v1.0.jar and jar2.v1.0.jar, I have to add a dependency in proj2-tests.launch to the libraries in proj1/lib. This translates to the following ugly lines in proj2-tests.launch: <listEntry value="<?xml version="1.0" encoding="UTF-8" standalone="no"?> <runtimeClasspathEntry path="3" projectName="proj1" type="1"/> "/> <listEntry value="<?xml version="1.0" encoding="UTF-8" standalone="no"?> <runtimeClasspathEntry internalArchive="/proj1/lib/jar1-v1.0.jar" path="3" type="2"/> "/> <listEntry value="<?xml version="1.0" encoding="UTF-8" standalone="no"?> <runtimeClasspathEntry internalArchive="/proj1/lib/jar2-v1.0.jar" path="3" type="2"/> "/> This wouldn't be a big problem if there wasn't the need from time to time to evolve the software, upgrade the libraries and etc. Consider the common need to upgrade the libraries jar1-v1.0.jar and jar2-v1.0.jar to their versions v1.1. Consider that you have about 10 projects in one workspace, having about 5 libraries each and about 4 launch configurations. You get a maintenance overhead in doing a simple upgrade of a library, which normally must imply changes in files for which there wasn't the need for. Or maybe I'm doing something wrong... What I would like to state is proj2 depends on proj1 and on its libraries and having this translated to simply that in the *.launch files. Is that possible?

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  • Google Code + SVN or GitHub + Git

    - by Nazgulled
    Let me start by telling you that I never used anything besides SVN and I'm also a Windows user. I have a couple of simple projects that are open-source, others are on there way when I'm happy enough to release their source code but either way, I was thinking of using Google Code and SVN to share the source code of my projects instead of providing a link to the source on my website. This as always been a pain cause I had to update the binaries and the code every time I released a new version. This would also help me out to have a backup of my code some where instead of just my local machine (I used to have a local Subversion server running). What I want from a service like this is very simple... I just want a place to store my source code that people can download if they want, allows me to control revisions and provide a simple and easy issue system so people can submit bugs and stuff like that. I guess both of them have this. But I don't want to host any binaries in their websites, I want this to be hosted on my website so I can control download statistics with my own scripts, I also don't have the need for wiki pages as I prefer to have all the documentation in my own website. Does anyone of this services provide a way to "disable" features like wiki and downloads and don't show them at all for my project(s)? Now, I'm sure there are lots of pros and cons about using Google Code with SVN and GitHub with Git (of course) but here's what it's important for me on each one and why I like them: Google Code: As with any Google page, the complexity is almost non-existent Everyone (or almost) as a Google account and this is nice if people want to report problems using the issues system GitHub: May (or may not) be a little more complex (not a problem for me though) than Google's pages but... ...has a much prettier interface than Google's service It needs people to be registered on GitHub to post about issues I like the fact that with Git, you have your own revisions locally (can I use TortoiseGit for this or?) Basically that's it, not much I know... What other, most common, pros and cons can you tell me about each site/software? Keep in mind that my projects are simple, I'm probably the only one who will ever develop these projects on these repositories (or maybe not, for now I will)

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  • Why I get java.net.SocketException: Connection reset

    - by Jammy
    I need sent some requests to server side and get reponse, sometimes when I call specific method to run the flollowing common code, I get one error in line(addToCookieJar(connection);), any idea how this get happened? URL url = new URL(providerURL); HttpURLConnection connection = (HttpURLConnection)url.openConnection(); connection.setRequestMethod("POST"); connection.setDoInput(true); connection.setDoOutput(true); connection.setUseCaches(false); connection.setRequestProperty("Content-Type", "application/octet-stream"); // We understand gzip encoding connection.addRequestProperty("Accept-Encoding", "gzip"); if (cookie != null && cookieHandler != null) { connection.setRequestProperty("Cookie", cookie); } if (cookieHandler == null) { addFromCookieJar(connection); } // Send the request ObjectOutputStream oos = new ObjectOutputStream(connection.getOutputStream()); oos.writeObject(remote.getName()); oos.writeObject(m.getName()); // method name oos.writeObject(m.getParameterTypes()); // formal parameters oos.writeObject(args); // actual parameters oos.flush(); oos.close(); if (cookieHandler == null) { cookieJar.put(new URI(providerURL), connection.getHeaderFields()); } Exception: java.lang.reflect.UndeclaredThrowableException at $Proxy0.updateDocument(Unknown Source) at com.agst.ui.gantt.GanttPanel.doUpdateDocument(GanttPanel.java:1931) at com.agst.ui.gantt.GanttPanel.save(GanttPanel.java:1419) at com.agst.ui.gantt.GanttPanel$4.run(GanttPanel.java:1673) at java.lang.Thread.run(Unknown Source) Caused by: java.net.SocketException: Connection reset at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method) at sun.reflect.NativeConstructorAccessorImpl.newInstance(Unknown Source) at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(Unknown Source) at java.lang.reflect.Constructor.newInstance(Unknown Source) at sun.net.www.protocol.http.HttpURLConnection$6.run(Unknown Source) at java.security.AccessController.doPrivileged(Native Method) at sun.net.www.protocol.http.HttpURLConnection.getChainedException(Unknown Source) at sun.net.www.protocol.http.HttpURLConnection.getInputStream(Unknown Source) at com.agst.rmi.RemoteCallHandler.call(RemoteCallHandler.java:196) at com.agst.rmi.RemoteCallHandler.invoke(RemoteCallHandler.java:142) ... 5 more Caused by: java.net.SocketException: Connection reset at java.net.SocketInputStream.read(Unknown Source) at java.io.BufferedInputStream.fill(Unknown Source) at java.io.BufferedInputStream.read1(Unknown Source) at java.io.BufferedInputStream.read(Unknown Source) at sun.net.www.http.HttpClient.parseHTTPHeader(Unknown Source) at sun.net.www.http.HttpClient.parseHTTP(Unknown Source) at sun.net.www.http.HttpClient.parseHTTP(Unknown Source) at sun.net.www.protocol.http.HttpURLConnection.getInputStream(Unknown Source) at sun.net.www.protocol.http.HttpURLConnection.getHeaderFields(Unknown Source) at com.agst.rmi.RemoteCallHandler.addToCookieJar(RemoteCallHandler.java:529) at com.agst.rmi.RemoteCallHandler.call(RemoteCallHandler.java:192) ... 6 more

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  • How does Sentry aggregate errors?

    - by Hugo Rodger-Brown
    I am using Sentry (in a django project), and I'd like to know how I can get the errors to aggregate properly. I am logging certain user actions as errors, so there is no underlying system exception, and am using the culprit attribute to set a friendly error name. The message is templated, and contains a common message ("User 'x' was unable to perform action because 'y'"), but is never exactly the same (different users, different conditions). Sentry clearly uses some set of attributes under the hood to determine whether to aggregate errors as the same exception, but despite having looked through the code, I can't work out how. Can anyone short-cut my having to dig further into the code and tell me what properties I need to set in order to manage aggregation as I would like? [UPDATE 1: event grouping] This line appears in sentry.models.Group: class Group(MessageBase): """ Aggregated message which summarizes a set of Events. """ ... class Meta: unique_together = (('project', 'logger', 'culprit', 'checksum'),) ... Which makes sense - project, logger and culprit I am setting at the moment - the problem is checksum. I will investigate further, however 'checksum' suggests that binary equivalence, which is never going to work - it must be possible to group instances of the same exception, with differenct attributes? [UPDATE 2: event checksums] The event checksum comes from the sentry.manager.get_checksum_from_event method: def get_checksum_from_event(event): for interface in event.interfaces.itervalues(): result = interface.get_hash() if result: hash = hashlib.md5() for r in result: hash.update(to_string(r)) return hash.hexdigest() return hashlib.md5(to_string(event.message)).hexdigest() Next stop - where do the event interfaces come from? [UPDATE 3: event interfaces] I have worked out that interfaces refer to the standard mechanism for describing data passed into sentry events, and that I am using the standard sentry.interfaces.Message and sentry.interfaces.User interfaces. Both of these will contain different data depending on the exception instance - and so a checksum will never match. Is there any way that I can exclude these from the checksum calculation? (Or at least the User interface value, as that has to be different - the Message interface value I could standardise.) [UPDATE 4: solution] Here are the two get_hash functions for the Message and User interfaces respectively: # sentry.interfaces.Message def get_hash(self): return [self.message] # sentry.interfaces.User def get_hash(self): return [] Looking at these two, only the Message.get_hash interface will return a value that is picked up by the get_checksum_for_event method, and so this is the one that will be returned (hashed etc.) The net effect of this is that the the checksum is evaluated on the message alone - which in theory means that I can standardise the message and keep the user definition unique. I've answered my own question here, but hopefully my investigation is of use to others having the same problem. (As an aside, I've also submitted a pull request against the Sentry documentation as part of this ;-)) (Note to anyone using / extending Sentry with custom interfaces - if you want to avoid your interface being use to group exceptions, return an empty list.)

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  • No value given for one or more required parameters in connection initialisation

    - by Jean-François Côté
    I have an C# form application that use an access database. This application works perfectly in debug and release. It works on all version of Windows. But it crash on one computer with Windows 7. The message I got is: System.Data.OleDb.OleDbException: No value given for one or more required parameters. EDIT, after some debugging with messagebox on the computer that have the problem, here is the code that bug.The error is catched on the cmd.ExecuteReader(). The messagebox juste before is shown and the next one is the one in the catch with the exception below. Any ideas? public List<CoeffItem> GetModeleCoeff() { List<CoeffItem> list = new List<CoeffItem>(); try { OleDbDataReader dr; OleDbCommand cmd = new OleDbCommand("SELECT nIDModelAquacad, nIDModeleBorne, fCoefficient FROM tbl_ModelBorne ORDER BY nIDModelAquacad", m_conn); MessageBox.Show("Commande SQL créée avec succès"); dr = cmd.ExecuteReader(); MessageBox.Show("Exécution du reader sans problème!"); while (dr.Read()) { list.Add(new CoeffItem(Convert.ToInt32(dr["nIDModelAquacad"].ToString()), Convert.ToInt32(dr["nIDModeleBorne"].ToString()), Convert.ToDouble(dr["fCoefficient"].ToString()))); } MessageBox.Show("Lecture du reader"); dr.Close(); MessageBox.Show("Fermeture du reader"); } catch (OleDbException err) { MessageBox.Show("Erreur dans la lecture des modèles/coefficient: " + err.ToString()); } return list; } I think it's something related to the connection string but why only on that computer. Thanks for your help! EDIT Here is the complete error message: See the end of this message for details on invoking just-in-time (JIT) debugging instead of this dialog box. ***** Exception Text ******* System.Data.OleDb.OleDbException: No value given for one or more required parameters. at System.Data.OleDb.OleDbCommand.ExecuteCommandTextErrorHandling(OleDbHResult hr) at System.Data.OleDb.OleDbCommand.ExecuteCommandTextForSingleResult(tagDBPARAMS dbParams, Object& executeResult) at System.Data.OleDb.OleDbCommand.ExecuteCommandText(Object& executeResult) at System.Data.OleDb.OleDbCommand.ExecuteCommand(CommandBehavior behavior, Object& executeResult) at System.Data.OleDb.OleDbCommand.ExecuteReaderInternal(CommandBehavior behavior, String method) at System.Data.OleDb.OleDbCommand.ExecuteReader(CommandBehavior behavior) at System.Data.OleDb.OleDbCommand.ExecuteReader() at DatabaseLayer.DatabaseFacade.GetModeleCoeff() at DatabaseLayer.DatabaseFacade.InitConnection(String strFile) at CalculatriceCHW.ListeMesure.OuvrirFichier(String strFichier) at CalculatriceCHW.ListeMesure.nouveauFichierMenu_Click(Object sender, EventArgs e) at System.Windows.Forms.ToolStripItem.RaiseEvent(Object key, EventArgs e) at System.Windows.Forms.ToolStripMenuItem.OnClick(EventArgs e) at System.Windows.Forms.ToolStripItem.HandleClick(EventArgs e) at System.Windows.Forms.ToolStripItem.HandleMouseUp(MouseEventArgs e) at System.Windows.Forms.ToolStripItem.FireEventInteractive(EventArgs e, ToolStripItemEventType met) at System.Windows.Forms.ToolStripItem.FireEvent(EventArgs e, ToolStripItemEventType met) at System.Windows.Forms.ToolStrip.OnMouseUp(MouseEventArgs mea) at System.Windows.Forms.ToolStripDropDown.OnMouseUp(MouseEventArgs mea) at System.Windows.Forms.Control.WmMouseUp(Message& m, MouseButtons button, Int32 clicks) at System.Windows.Forms.Control.WndProc(Message& m) at System.Windows.Forms.ScrollableControl.WndProc(Message& m) at System.Windows.Forms.ToolStrip.WndProc(Message& m) at System.Windows.Forms.ToolStripDropDown.WndProc(Message& m) at System.Windows.Forms.Control.ControlNativeWindow.OnMessage(Message& m) at System.Windows.Forms.Control.ControlNativeWindow.WndProc(Message& m) at System.Windows.Forms.NativeWindow.Callback(IntPtr hWnd, Int32 msg, IntPtr wparam, IntPtr lparam)

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  • LinearLayout as custom button, OnClickListener never called

    - by ohra
    I've been using the common Android Button with both icon (drawableTop) and text. It works really poorly if you want to have a non-standard size button, so I decided to make a custom button with a LinearLayout having the following layout: <?xml version="1.0" encoding="utf-8"?> <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android" style="@style/ButtonHoloDark" android:layout_width="fill_parent" android:layout_height="fill_parent" android:gravity="center" android:clickable="true" android:focusable="true" android:orientation="vertical" > <ImageView android:id="@+id/buttonIcon" android:layout_width="fill_parent" android:layout_height="wrap_content" android:duplicateParentState="true" /> <TextView android:id="@+id/buttonText" android:layout_width="fill_parent" android:layout_height="wrap_content" android:duplicateParentState="true" android:gravity="center" android:textColor="@color/white" /> </LinearLayout> The layout is used by a custom class: public class CustomIconButton extends LinearLayout { public CustomIconButton(Context context, AttributeSet attrs) { super(context, attrs); setAttributes(context, attrs); LayoutInflater.from(context).inflate(R.layout.custom_icon_button, this, true); } ... But when I set an OnClickListener on my button in its parent layout it never gets called. I can only receive clicks if a set the listener to the ImageView and/or TextView. This leads to two possible effects when the button is clicked: The click is inside the ImageView or the TextView. The click is registered ok, but the buttons state drawable doesn't change i.e. it doesn't appear depressed. The click is inside the "empty area" of the button. The click is not registered, but the state drawable works ok. Neither of these is feasible. I've played around with the following attributes on the LinearLayout or its children, but none really seem to have any effect whether true or false: duplicateParentState clickable focusable There doesn't seem to be any reasonable way to get the LinearLayout parent receive clicks instead of its children. I've seen some possible solutions overriding dispatchTouchEvent or onInterceptTouchEvent on the custom component itself, but that really seems like a big mess if I have to start analyzing touch events to identify proper clicks. So OnClickListener on a LinearLayout with children = no go?

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  • Polymorphic :has_many, :through as module in Rails 3.1 plugin

    - by JohnMetta
    I've search everywhere for a pointer to this, but can't find one. Basically, I want to do what everyone else wants to do when they create a polymorphic relationship in a :has_many, :through way… but I want to do it in a module. I keep getting stuck and think I must be overlooking something simple. To wit: module ActsPermissive module PermissiveUser def self.included(base) base.extend ClassMethods end module ClassMethods def acts_permissive has_many :ownables has_many :owned_circles, :through => :ownables end end end class PermissiveCircle < ActiveRecord::Base belongs_to :ownable, :polymorphic => true end end With a migration that looks like this: create_table :permissive_circles do |t| t.string :ownable_type t.integer :ownable_id t.timestamps end The idea, of course, is that whatever loads acts_permissive will be able to have a list of circles that it owns. For simple tests, I have it "should have a list of circles" do user = Factory :user user.owned_circles.should be_an_instance_of Array end which fails with: Failure/Error: @user.circles.should be_an_instance_of Array NameError: uninitialized constant User::Ownable I've tried: using :class_name => 'ActsPermissive::PermissiveCircle' on the has_many :ownables line, which fails with: Failure/Error: @user.circles.should be_an_instance_of Array ActiveRecord::HasManyThroughSourceAssociationNotFoundError: Could not find the source association(s) :owned_circle or :owned_circles in model ActsPermissive::PermissiveCircle. Try 'has_many :owned_circles, :through => :ownables, :source => <name>'. Is it one of :ownable? while following the suggestion and setting :source => :ownable fails with Failure/Error: @user.circles.should be_an_instance_of Array ActiveRecord::HasManyThroughAssociationPolymorphicSourceError: Cannot have a has_many :through association 'User#owned_circles' on the polymorphic object 'Ownable#ownable' Which seems to suggest that doing things with a non-polymorphic-through is necessary. So I added a circle_owner class similar to the setup here: module ActsPermissive class CircleOwner < ActiveRecord::Base belongs_to :permissive_circle belongs_to :ownable, :polymorphic => true end module PermissiveUser def self.included(base) base.extend ClassMethods end module ClassMethods def acts_permissive has_many :circle_owners, :as => :ownable has_many :circles, :through => :circle_owners, :source => :ownable, :class_name => 'ActsPermissive::PermissiveCircle' end end class PermissiveCircle < ActiveRecord::Base has_many :circle_owners end end With a migration: create_table :permissive_circles do |t| t.string :name t.string :guid t.timestamps end create_table :circle_owner do |t| t.string :ownable_type t.string :ownable_id t.integer :permissive_circle_id end which still fails with: Failure/Error: @user.circles.should be_an_instance_of Array NameError: uninitialized constant User::CircleOwner Which brings us back to the beginning. How can I do what seems to be a rather common polymorphic :has_many, :through on a module? Alternatively, is there a good way to allow an object to be collected by arbitrary objects in a similar way that will work with a module?

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  • Modular GWT design concerns

    - by GlGuru
    Hi, I have a couple of questions regarding a modular GWT based application framework. I have some ideas about them but being new to the field of web development I feel they are far from ideal. I'd appreciate a few comments and suggestions in this regard. Here are my questions: I am developing a framework which will allow third parties to embed GWT applications into our website and do some communication with them using simple iFrame postMessage. All these third party modules are going to use our SDK which is also GWT based. The problem arises that even though all the modules will be using the same codebase there is going to be a massive overheard in the amount of duplicate Javascript code (i.e. our common SDK code base which is quite large) being downloaded on the client's machine. This is highly redundant and problematic, not only due to the sheer size of duplicate code but, also due to the fact that subsequent updates of the SDK would require the modules to be recompiled which is going to create a DLL hell kind of scenario in the long run. What is the best way of doing this kind of thing? Is there a way where I can have some static GWT code (i.e. the SDK) and the dynamic GWT module refers to it (even if lies on a different domain) and it all work happily? The other part of the problem lies in providing robust scripting front end to the SDK. At first it appears to be trivial since Javascript itself is a scripting language. However, I do not know how to load and call a piece of pure Javascript code at runtime? I am willing to put restrictions on the target Javascript (i.e. having a function main and unique namespace or something). Furthermore the Javascript will come as a string from a database and not as a full URL. If its doable in Javascript how does one get this right in GWT i.e. forcing the compiler to emit a certain function in the generated Javascript? This I believe can be lesser of a problem by having a stub Javascript with all the right requirements which just loads up a GWT generated Javascript. Is any of this possible at all? I generally hate to be this verbose but I hope to find a quick solution to the problem as its holding up my progress. I'd highly appreciate any comments, suggestions and experiences.

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  • Foreign key pointing to different tables

    - by Álvaro G. Vicario
    I'm implementing a table per subclass design I discussed in a previous question. It's a product database where products can have very different attributes depending on their type, but attributes are fixed for each type and types are not manageable at all. I have a master table that holds common attributes: product_type ============ product_type_id INT product_type_name VARCHAR E.g.: 1 'Magazine' 2 'Web site' product ======= product_id INT product_name VARCHAR product_type_id INT -> Foreign key to product_type.product_type_id valid_since DATETIME valid_to DATETIME E.g. 1 'Foo Magazine' 1 '1998-12-01' NULL 2 'Bar Weekly Review' 1 '2005-01-01' NULL 3 'E-commerce App' 2 '2009-10-15' NULL 4 'CMS' 2 '2010-02-01' NULL ... and one subtable for each product type: item_magazine ============= item_magazine_id INT title VARCHAR product_id INT -> Foreign key to product.product_id issue_number INT pages INT copies INT close_date DATETIME release_date DATETIME E.g. 1 'Foo Magazine Regular Issue' 1 89 52 150000 '2010-06-25' '2010-06-31' 2 'Foo Magazine Summer Special' 1 90 60 175000 '2010-07-25' '2010-07-31' 3 'Bar Weekly Review Regular Issue' 2 12 16 20000 '2010-06-01' '2010-06-02' item_web_site ============= item_web_site_id INT name VARCHAR product_id INT -> Foreign key to product.product_id bandwidth INT hits INT date_from DATETIME date_to DATETIME E.g. 1 'The Carpet Store' 3 10 90000 '2010-06-01' NULL 2 'Penauts R Us' 3 20 180000 '2010-08-01' NULL 3 'Springfield Cattle Fair' 4 15 150000 '2010-05-01' '2010-10-31' Now I want to add some fees that relate to one specific item. Since there are very little subtypes, it's feasible to do this: fee === fee_id INT fee_description VARCHAR item_magazine_id INT -> Foreign key to item_magazine.item_magazine_id item_web_site_id INT -> Foreign key to item_web_site.item_web_site_id net_price DECIMAL E.g.: 1 'Front cover' 2 NULL 1999.99 2 'Half page' 2 NULL 500.00 3 'Square banner' NULL 3 790.50 4 'Animation' NULL 3 2000.00 I have tight foreign keys to handle cascaded editions and I presume I can add a constraint so only one of the IDs is NOT NULL. However, my intuition suggests that it would be cleaner to get rid of the item_WHATEVER_id columns and keep a separate table: fee_to_item =========== fee_id INT -> Foreign key to fee.fee_id product_id INT -> Foreign key to product.product_id item_id INT -> ??? But I can't figure out how to create foreign keys on item_id since the source table varies depending on product_id. Should I stick to my original idea?

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  • Precise explanation of JavaScript <-> DOM circular reference issue

    - by Joey Adams
    One of the touted advantages of jQuery.data versus raw expando properties (arbitrary attributes you can assign to DOM nodes) is that jQuery.data is "safe from circular references and therefore free from memory leaks". An article from Google titled "Optimizing JavaScript code" goes into more detail: The most common memory leaks for web applications involve circular references between the JavaScript script engine and the browsers' C++ objects' implementing the DOM (e.g. between the JavaScript script engine and Internet Explorer's COM infrastructure, or between the JavaScript engine and Firefox XPCOM infrastructure). It lists two examples of circular reference patterns: DOM element → event handler → closure scope → DOM DOM element → via expando → intermediary object → DOM element However, if a reference cycle between a DOM node and a JavaScript object produces a memory leak, doesn't this mean that any non-trivial event handler (e.g. onclick) will produce such a leak? I don't see how it's even possible for an event handler to avoid a reference cycle, because the way I see it: The DOM element references the event handler. The event handler references the DOM (either directly or indirectly). In any case, it's almost impossible to avoid referencing window in any interesting event handler, short of writing a setInterval loop that reads actions from a global queue. Can someone provide a precise explanation of the JavaScript ↔ DOM circular reference problem? Things I'd like clarified: What browsers are effected? A comment in the jQuery source specifically mentions IE6-7, but the Google article suggests Firefox is also affected. Are expando properties and event handlers somehow different concerning memory leaks? Or are both of these code snippets susceptible to the same kind of memory leak? // Create an expando that references to its own element. var elem = document.getElementById('foo'); elem.myself = elem; // Create an event handler that references its own element. var elem = document.getElementById('foo'); elem.onclick = function() { elem.style.display = 'none'; }; If a page leaks memory due to a circular reference, does the leak persist until the entire browser application is closed, or is the memory freed when the window/tab is closed?

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  • Basic shared memory program in C

    - by nicopuri
    Hi, I want to make a basic chat application in C using Shared memory. I am working in Linux. The application consist in writing the client and the server can read, and if the server write the client can read the message. I tried to do this, but I can't achieve the communication between client and server. The code is the following: Server.c int main(int argc, char **argv) { char *msg; static char buf[SIZE]; int n; msg = getmem(); memset(msg, 0, SIZE); initmutex(); while ( true ) { if( (n = read(0, buf, sizeof buf)) 0 ) { enter(); sprintf(msg, "%.*s", n, buf); printf("Servidor escribe: %s", msg); leave(); }else{ enter(); if ( strcmp(buf, msg) ) { printf("Servidor lee: %s", msg); strcpy(buf, msg); } leave(); sleep(1); } } return 0; } Client.c int main(int argc, char **argv) { char *msg; static char buf[SIZE-1]; int n; msg = getmem(); initmutex(); while(true) { if ( (n = read(0, buf, sizeof buf)) 0 ) { enter(); sprintf(msg, "%.*s", n, buf); printf("Cliente escribe: %s", msg); leave(); }else{ enter(); if ( strcmp(buf, msg) ) { printf("Cliente lee: %s", msg); strcpy(buf, msg); } leave(); sleep(1); } } printf("Cliente termina\n"); return 0; } The shared memory module is the folowing: #include "common.h" void fatal(char *s) { perror(s); exit(1); } char * getmem(void) { int fd; char *mem; if ( (fd = shm_open("/message", O_RDWR|O_CREAT, 0666)) == -1 ) fatal("sh_open"); ftruncate(fd, SIZE); if ( !(mem = mmap(NULL, SIZE, PROT_READ|PROT_WRITE, MAP_SHARED, fd, 0)) ) fatal("mmap"); close(fd); return mem; } static sem_t *sd; void initmutex(void) { if ( !(sd = sem_open("/mutex", O_RDWR|O_CREAT, 0666, 1)) ) fatal("sem_open"); } void enter(void) { sem_wait(sd); } void leave(void) { sem_post(sd); }

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  • What does a WinForm application need to be designed for usability, and be robust, clean, and profess

    - by msorens
    One of the principal problems impeding productivity in software implementation is the classic conundrum of “reinventing the wheel”. Of late I am a .NET developer and even the wonderful wizardry of .NET and Visual Studio covers only a portion of this challenging issue. Below I present my initial thoughts both on what is available and what should be available from .NET on a WinForm, focusing on good usability. That is, aspects of an application exposed to the user and making the user experience easier and/or better. (I do include a couple items not visible to the user because I feel strongly about them, such as diagnostics.) I invite you to contribute to these lists. LIST A: Components provided by .NET These are substantially complete components provided by .NET, i.e. those requiring at most trivial coding to use. “About” dialog -- add it with a couple clicks then customize. Persist settings across invocations -- .NET has the support; just use a few lines of code to glue them together. Migrate settings with a new version -- a powerful one, available with one line of code. Tooltips (and infotips) -- .NET includes just plain text tooltips; third-party libraries provide richer ones. Diagnostic support -- TraceSources, TraceListeners, and more are built-in. Internationalization -- support for tailoring your app to languages other than your own. LIST B: Components not provided by .NET These are not supplied at all by .NET or supplied only as rudimentary elements requiring substantial work to be realized. Splash screen -- a small window present during program startup with your logo, loading messages, etc. Tip of the day -- a mini-tutorial presented one bit at a time each time the user starts your app. Check for available updates -- facility to query a server to see if the user is running the latest version of your app, then provide a simple way to upgrade if a new version is found. Maximize to multiple monitors -- the canonical window allows you to maximize to a single monitor only; in my apps I allow maximizing across multiple monitors with a click. Taskbar notifier -- flash the taskbar when your backgrounded app has new info for the user. Options dialogs -- multi-page dialogs letting the user customize the app settings to his/her own preferences. Progress indicator -- for long running operations give the user feedback on how far there is left to go. Memory gauge -- an indicator (either absolute or percentage) of how much memory is used by your app. LIST C: Stylistic and/or tiny bits of functionality This list includes bits of functionality that are too tiny to merit being called a component, along with stylistic concerns (that admittedly do overlap with the Windows User Experience Interaction Guidelines). Design a form for resizing -- unless you are restricting your form to be a fixed size, use anchors and docking so that it does what is reasonable when enlarged or shrunk by the user. Set tab order on a form -- repeated tab presses by the user should advance from field to field in a logical order rather than the default order in which you added fields. Adjust controls to be aware of operating modes -- When starting a background operation with, for example, a “Go” button, disable that “Go” button until the operation completes. Provide access keys for all menu items (per UXGuide). Provide shortcut keys for commonly used menu items (per UXGuide). Set up some (global or important or common) shortcut keys without associating to menu items. Allow some menu items to be invoked with or without modifier keys (shift, control, alt) where the modifier key is useful to vary the operation slightly. Hook up Escape and Enter on child forms to do what is reasonable. Decorate any library classes with documentation-comments and attributes -- this allows Visual Studio to leverage them for Intellisense and property descriptions. Spell check your code! What else would you include?

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  • approximating log10[x^k0 + k1]

    - by Yale Zhang
    Greetings. I'm trying to approximate the function Log10[x^k0 + k1], where .21 < k0 < 21, 0 < k1 < ~2000, and x is integer < 2^14. k0 & k1 are constant. For practical purposes, you can assume k0 = 2.12, k1 = 2660. The desired accuracy is 5*10^-4 relative error. This function is virtually identical to Log[x], except near 0, where it differs a lot. I already have came up with a SIMD implementation that is ~1.15x faster than a simple lookup table, but would like to improve it if possible, which I think is very hard due to lack of efficient instructions. My SIMD implementation uses 16bit fixed point arithmetic to evaluate a 3rd degree polynomial (I use least squares fit). The polynomial uses different coefficients for different input ranges. There are 8 ranges, and range i spans (64)2^i to (64)2^(i + 1). The rational behind this is the derivatives of Log[x] drop rapidly with x, meaning a polynomial will fit it more accurately since polynomials are an exact fit for functions that have a derivative of 0 beyond a certain order. SIMD table lookups are done very efficiently with a single _mm_shuffle_epi8(). I use SSE's float to int conversion to get the exponent and significand used for the fixed point approximation. I also software pipelined the loop to get ~1.25x speedup, so further code optimizations are probably unlikely. What I'm asking is if there's a more efficient approximation at a higher level? For example: Can this function be decomposed into functions with a limited domain like log2((2^x) * significand) = x + log2(significand) hence eliminating the need to deal with different ranges (table lookups). The main problem I think is adding the k1 term kills all those nice log properties that we know and love, making it not possible. Or is it? Iterative method? don't think so because the Newton method for log[x] is already a complicated expression Exploiting locality of neighboring pixels? - if the range of the 8 inputs fall in the same approximation range, then I can look up a single coefficient, instead of looking up separate coefficients for each element. Thus, I can use this as a fast common case, and use a slower, general code path when it isn't. But for my data, the range needs to be ~2000 before this property hold 70% of the time, which doesn't seem to make this method competitive. Please, give me some opinion, especially if you're an applied mathematician, even if you say it can't be done. Thanks.

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  • How do you combine "Revision Control" with "WorkFlow" for R?

    - by Tal Galili
    Hello all, I remember coming across R users writing that they use "Revision control" (e.g: "Source control"), and I am curious to know: How do you combine "Revision control" with your statistical analysis WorkFlow? Two (very) interesting discussions talk about how to deal with the WorkFlow. But neither of them refer to the revision control element: http://stackoverflow.com/questions/1266279/how-to-organize-large-r-programs http://stackoverflow.com/questions/1429907/workflow-for-statistical-analysis-and-report-writing A Long Update To The Question: Following some of the people's answers, and Dirk's question in the comment, I would like to direct my question a bit more. After reading the Wiki article about "revision control" (which I was previously not familiar with), it was clear to me that when using revision control, what one does is to build a development structure of his code. This structure either leads to a "final product" or to several branches. When building something like, let's say, a website. There is usually one end product you work towards (the website), with some prototypes along the way. But when doing a statistical analysis, the work (to my view) is different. Sometimes you know where you want to get to. But more often, you explore. Explore cleaning the dataset. Explore different methods for statistical analysis, and ask various questions of your data (and I am writing this, knowing how Frank Harrell, and other experience statisticians feels about Data dredging). That is way the WorkFlow question with statistical programming is (in my view) a serious and deep question, raising many issues, The simpler ones are technical: Which revision control software do you use (and why) ? Which IDE do you use(and why) ? The more interesting question are about work process: How do you structure your files? What do you keep as a separate file and what as a revision? or asking in a different way - What should be a "branch" and what should be a "sub project" in your code? For example: When starting to explore your data, should a plot be creating and then erased because it didn't lead any where (but kept as a revision) or should there be a backup file of that path? How you solve this tension was my initial curiosity. The second question is "what might I be missing?". What rules (of thumb) should one follow so to avoid common pitfalls doing statistical programming with version control? In my intuition, I feel that statistical programming is inherently different then software development (I am writing this without being a real expert in statistical programming, and even less so in software development). That's way I am unsure which of the lessons I have read here about version control would be applicable. Thanks a lot, Tal

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  • How add loading image using jquery?

    - by user244394
    I'm working on a form, <form id="myform" class="form"> </form> that gets submitted to the server using jquery ajax. How can I refresh the form on success to show the updated form information and add a spinner until the form loads? here is my html and jquery snippet <div class="container"> <div class="page-header"> <div class="span2"> <!--Sidebar content--> <img src="img/emc_logo.png" title="EMC" > </div> <div class="span6"> <h2 class="form-wizard-heading">Configuration</h2> </div> </div> <form id="myform" class="form"> </form> </div> <!-- /container --> <!-- Modal --> <div id="myModal" class="modal hide fade" tabindex="-1" role="dialog" aria-labelledby="myModalLabel" aria-hidden="true"> <div class="modal-header"> <button type="button" class="close" data-dismiss="modal" aria-hidden="true">&times;</button> <h3 id="myModalLabel">Configuration Changes</h3> <p><span class="label label-important">Please review your changes before submitting. Submitting the changes will result in rebooting the cluster</span></p> </div> <div class="modal-body"> <table class="table table-condensed table-striped" id="display"></table> </div> <div class="modal-footer"> <button id="cancel" class="btn" data-dismiss="modal" aria-hidden="true">Close</button> <button id="save" class="btn btn-primary">Save changes</button> </div> </div> //Jquery part $(document).ready(function () { $('input').hover(function () { $(this).popover('show') }); // On mouseout destroy popout $('input').mouseout(function () { $(this).popover('destroy') }); $('#myform').on('submit', function (ev) { ev.preventDefault(); var data = $(this).serializeObject(); json_data = JSON.stringify(data); $('#myModal').modal('show'); $.each(data, function (key, val) { var tablefeed = $('<tr><td>' + key + '</td><td id="' + key + '">' + val + '</td><tr>').appendTo('#display'); }); $(".modal-body").html(tablefeed); }); $("#cancel").click(function () { $("#display").empty(); }); $(function () { $("#save").click(function () { // validate and process form here alert("button submitted" + json_data); $.ajax({ type: "POST", url: "somefile.json.", data: json_data, contentType: 'application/json', success: function (data, textStatus, xhr) { console.log(arguments); console.log(xhr.status); alert("Your form has been submitted: " + textStatus + xhr.status); }, error: function (jqXHR, textStatus, errorThrown) { alert(jqXHR.responseText + " - " + errorThrown + " : " + jqXHR.status); } }); }); }); });

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  • SSL Authentication with Certificates: Should the Certificates have a hostname?

    - by sixtyfootersdude
    Summary JBoss allows clients and servers to authenticate using certificates and ssl. One thing that seems strange is that you are not required to give your hostname on the certificate. I think that this means if Server B is in your truststore, Sever B can pretend to be any server that they want. (And likewise: if Client B is in your truststore...) Am I missing something here? Authentication Steps (Summary of Wikipeida Page) Client Server ================================================================================================= 1) Client sends Client Hello ENCRIPTION: None - highest TLS protocol supported - random number - list of cipher suites - compression methods 2) Sever Hello ENCRIPTION: None - highest TLS protocol supported - random number - choosen cipher suite - choosen compression method 3) Certificate Message ENCRIPTION: None - 4) ServerHelloDone ENCRIPTION: None 5) Certificate Message ENCRIPTION: None 6) ClientKeyExchange Message ENCRIPTION: server's public key => only server can read => if sever can read this he must own the certificate - may contain a PreMasterSecerate, public key or nothing (depends on cipher) 7) CertificateVerify Message ENCRIPTION: clients private key - purpose is to prove to the server that client owns the cert 8) BOTH CLIENT AND SERVER: - use random numbers and PreMasterSecret to compute a common secerate 9) Finished message - contains a has and MAC over previous handshakes (to ensure that those unincripted messages did not get broken) 10) Finished message - samething Sever Knows The client has the public key for the sent certificate (step 7) The client's certificate is valid because either: it has been signed by a CA (verisign) it has been self-signed BUT it is in the server's truststore It is not a replay attack because presumably the random number (step 1 or 2) is sent with each message Client Knows The server has the public key for the sent certificate (step 6 with step 8) The server's certificate is valid because either: it has been signed by a CA (verisign) it has been self-signed BUT it is in the client's truststore It is not a replay attack because presumably the random number (step 1 or 2) is sent with each message Potential Problem Suppose the client's truststore has certs in it: Server A Server B (malicous) Server A has hostname www.A.com Server B has hostname www.B.com Suppose: The client tries to connect to Server A but Server B launches a man in the middle attack. Since server B: has a public key for the certificate that will be sent to the client has a "valid certificate" (a cert in the truststore) And since: certificates do not have a hostname feild in them It seems like Server B can pretend to be Server A easily. Is there something that I am missing?

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  • Emacs, C++ code completion for vectors

    - by Caglar Toklu
    Hi, I am new to Emacs, and I have the following code as a sample. I have installed GNU Emacs 23.1.1 (i386-mingw-nt6.1.7600), installed cedet-1.0pre7.tar.gz. , installed ELPA, and company. You can find my simple Emacs configuration at the bottom. The problem is, when I type q[0] in main() and press . (dot), I see the 37 members of the vector, not Person although first_name and last_name are expected. The completion works as expected in the function greet() but it has nothing to do with vector. My question is, how can I accomplish code completion for vector elements too? #include <iostream> #include <vector> using namespace std; class Person { public: string first_name; string last_name; }; void greet(Person a_person) { // a_person.first_name is completed as expected! cout << a_person.first_name << "|"; cout << a_person.last_name << endl; }; int main() { vector<Person> q(2); Person guy1; guy1.first_name = "foo"; guy1.last_name = "bar"; Person guy2; guy2.first_name = "stack"; guy2.last_name = "overflow"; q[0] = guy1; q[1] = guy2; greet(guy1); greet(guy2); // cout q[0]. I want to see first_name or last_name here! } My Emacs configuration: ;;; This was installed by package-install.el. ;;; This provides support for the package system and ;;; interfacing with ELPA, the package archive. ;;; Move this code earlier if you want to reference ;;; packages in your .emacs. (when (load (expand-file-name "~/.emacs.d/elpa/package.el")) (package-initialize)) (load-file "~/.emacs.d/cedet/common/cedet.el") (semantic-load-enable-excessive-code-helpers) (require 'semantic-ia) (global-srecode-minor-mode 1) (semantic-add-system-include "/gcc/include/c++/4.4.2" 'c++-mode) (semantic-add-system-include "/gcc/i386-pc-mingw32/include" 'c++-mode) (semantic-add-system-include "/gcc/include" 'c++-mode) (defun my-semantic-hook () (imenu-add-to-menubar "TAGS")) (add-hook 'semantic-init-hooks 'my-semantic-hook)

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  • How do I add Objective C code to a FireBreath Project?

    - by jmort253
    I am writing a browser plugin for Mac OS that will place a status bar icon in the status bar, which users can use to interface with the browser plugin. I've successfully built a FireBreath 1.6 project in XCode 4.4.1, and can install it in the browser. However, FireBreath uses C++, whereas a large majority of the existing libraries for Mac OS are written in Objective C. In the /Mac/projectDef.make file, I added the Cocoa Framework and Foundation Framework, as suggested here and in other resources I've found on the Internet: target_link_libraries(${PROJECT_NAME} ${PLUGIN_INTERNAL_DEPS} ${Cocoa.framework} # added line ${Foundation.framework} # added line ) I reran prepmac.sh, expecting a new project to be created in XCode with my .mm files, and .m files; however, it seems that they're being ignored. I only see the .cpp and .h files. I added rules for those in the projectDef.make file, but it doesn't seem to make a difference: file (GLOB PLATFORM RELATIVE ${CMAKE_CURRENT_SOURCE_DIR} Mac/[^.]*.cpp Mac/[^.]*.h Mac/[^.]*.m #added by me Mac/[^.]*.mm #added by me Mac/[^.]*.cmake ) Even if I add the files in manually, I get a series of compilation errors. There are about 20 of them, all related to the file NSObjRuntime.h file: Parse Issue - Expected unqualified-id Parse Issue - Unknown type name 'NSString' Semantic Issue - Use of undeclared identifier 'NSString' Parse Issue - Unknown type name 'NSString' ... ... Semantic Issue - Use of undeclared identifier 'aSelectorName' ... ... Semantic Issue - Use of undeclared identifier 'aClassName' ... It continues like this for some time with similar errors... From what I've read, these errors appear because of dependencies on the Foundation Framework, which I believe I've included in the project. I also tried clicking the project in XCode I'm to the point now where I'm not sure what to try next. People say it's not hard to use Objective C in C/C++ code, but being new to XCode and Objective C might contribute to my confusion. This is only day 4 for me in this new platform. What do I need to do to get XCode to compile the Objective C code? Please remember that I'm a little new to this, so I'd appreciate it if you leave detailed answers as opposed to the vague one-liners that are common in the firebreath tag. I'm just a little in over my head, but if you can get me past this hurdle I'm certain I'll be good to go from there. UPDATE: I edited projects/MyPlugin/CMakeLists.txt and added in the .m and .mm rules there too. after running prepmac.sh, the files are included in the project, but I still get the same compile errors. I moved all the .h files and .mm files from the Obj C code to the MyPlugin root folder and reran the prepmac.sh file. Problem still exists. Same compile errors.

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  • WinForm-style Invoke() in unmanaged C++

    - by Matt Green
    I've been playing with a DataBus-type design for a hobby project, and I ran into an issue. Back-end components need to notify the UI that something has happened. My implementation of the bus delivers the messages synchronously with respect to the sender. In other words, when you call Send(), the method blocks until all the handlers have called. (This allows callers to use stack memory management for event objects.) However, consider the case where an event handler updates the GUI in response to an event. If the handler is called, and the message sender lives on another thread, then the handler cannot update the GUI due to Win32's GUI elements having thread affinity. More dynamic platforms such as .NET allow you to handle this by calling a special Invoke() method to move the method call (and the arguments) to the UI thread. I'm guessing they use the .NET parking window or the like for these sorts of things. A morbid curiosity was born: can we do this in C++, even if we limit the scope of the problem? Can we make it nicer than existing solutions? I know Qt does something similar with the moveToThread() function. By nicer, I'll mention that I'm specifically trying to avoid code of the following form: if(! this->IsUIThread()) { Invoke(MainWindowPresenter::OnTracksAdded, e); return; } being at the top of every UI method. This dance was common in WinForms when dealing with this issue. I think this sort of concern should be isolated from the domain-specific code and a wrapper object made to deal with it. My implementation consists of: DeferredFunction - functor that stores the target method in a FastDelegate, and deep copies the single event argument. This is the object that is sent across thread boundaries. UIEventHandler - responsible for dispatching a single event from the bus. When the Execute() method is called, it checks the thread ID. If it does not match the UI thread ID (set at construction time), a DeferredFunction is allocated on the heap with the instance, method, and event argument. A pointer to it is sent to the UI thread via PostThreadMessage(). Finally, a hook function for the thread's message pump is used to call the DeferredFunction and de-allocate it. Alternatively, I can use a message loop filter, since my UI framework (WTL) supports them. Ultimately, is this a good idea? The whole message hooking thing makes me leery. The intent is certainly noble, but are there are any pitfalls I should know about? Or is there an easier way to do this?

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  • Problem with continue in While Loop within Try/Catch in C# (2.0)

    - by csharpnoob
    Hi, when i try to use in my ASPX Webpage in the Code Behind this try{ while() { ... db.Open(); readDataMoney = new OleDbCommand("SELECT * FROM Customer WHERE card = '" + customer.card + "';", db).ExecuteReader(); while (readDataMoney.Read()) { try { if (!readDataMoney.IsDBNull(readDataMoney.GetOrdinal("Credit"))) { customer.credit = Convert.ToDouble(readDataMoney[readDataMoney.GetOrdinal("Credit")]); } if (!readDataMoney.IsDBNull(readDataMoney.GetOrdinal("Bonus"))) { customer.bonus = Convert.ToDouble(readDataMoney[readDataMoney.GetOrdinal("Bonus")]); } } catch (Exception ex) { Connector.writeLog("Money: " + ex.StackTrace + "" + ex.Message + "" + ex.Source); customer.credit = 0.0; customer.credit = 0.0; continue; } finally { } } readDataMoney.Close(); vsiDB.Close(); ... } }catch { continue; } The whole page hangs if there is a problem when the read from db isn't working. I tried to check for !isNull, but same problem. I have a lots of differend MDB Files to process, which are readonly (can't repair/compact) and some or others not. Same Design/Layout of Tables. With good old ASP Classic 3.0 all of them are processing with the "On Resume Next". I know I know. But that's how it is. Can't change the source. So the basic question: So is there any way to tell .NET to continue the loop whatever happens within the try loop if there is any exception? After a lots of wating time i get this exceptions: at System.Data.Common.UnsafeNativeMethods.IDBInitializeInitialize.Invoke(IntPtr pThis) at System.Data.OleDb.DataSourceWrapper.InitializeAndCreateSession(OleDbConnectionString constr, SessionWrapper& sessionWrapper) at System.Data.OleDb.OleDbConnectionInternal..ctor(OleDbConnectionString constr, OleDbConnection connection) at System.Data.OleDb.OleDbConnectionFactory.CreateConnection(DbConnectionOptions options, Object poolGroupProviderInfo, DbConnectionPool pool, DbConnection owningObject) at System.Data.ProviderBase.DbConnectionFactory.CreateNonPooledConnection(DbConnection owningConnection, DbConnectionPoolGroup poolGroup) at System.Data.ProviderBase.DbConnectionFactory.GetConnection(DbConnection owningConnection) at System.Data.ProviderBase.DbConnectionClosed.OpenConnection(DbConnection outerConnection, DbConnectionFactory connectionFactory) at System.Data.OleDb.OleDbConnection.Open() at GetCustomer(String card)Thread was being aborted.System.Data and System.Runtime.InteropServices.Marshal.ReadInt16(IntPtr ptr, Int32 ofs) System.Data.ProviderBase.DbBuffer.ReadInt16(Int32 offset) System.Data.OleDb.ColumnBinding.Value_I2() System.Data.OleDb.ColumnBinding.Value() System.Data.OleDb.OleDbDataReader.GetValue(Int32 ordinal) System.Data.OleDb.OleDbDataReader.get_Item(Int32 index) Thread was terminated.mscorlib Thanks for any help.

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  • how to animate 2 surfaces in Matlab?

    - by Kate
    Hi everyone, I've written this code which makes an animation of 2 ellipsoids. Parameter k1 of these ellipsoids must depend on time (so they'd move asynchronously), but I need to animate them in one figure. Can I use loop for it or is it better to use timer & some kind of callback functions? The second problem - I need to move inner ellipsoid so they would have one common side. How can I do this? a=5; b=a; c=10; u = (0:0.05*pi:2*pi)'; v = [0:0.05*pi:2*pi]; X = a*sin(u)*cos(v); Y = a*sin(u)*sin(v); Z = c*cos(u)*ones(size(v)); Z(Z0)=0; % cut upper V1=4/3*pi*a*b*c; d=1/2; e=2^d; a2=a/e; b2=a/e; c2=c; V2=4/3*pi*a2*b2*c2; X2 = a2*sin(u)*cos(v);%-2.5; Y2 = b2*sin(u)*sin(v); Z2 = c2*cos(u)*ones(size(v));%+0.25; Z2(Z20)=0; % cut h=1/3; for j = 1:20 k1=(sin(pi*j/20)+0.5)^h; a=a*k1; c=c*k1; X = a*sin(u)*cos(v); Y = a*sin(u)*sin(v); Z = c*cos(u)*ones(size(v)); Z(Z0)=0; a2=a2*k1; b2=a2*k1; c2=c2*k1; X2 = a2*sin(u)*cos(v)+5;%-2.5; Y2 = b2*sin(u)*sin(v); Z2 = c2*cos(u)*ones(size(v));%+0.25; Z2(Z20)=0; hS1=surf(X,Y,Z); alpha(.11) hold on hS2=surf(X2,Y2,Z2); hold off axis([-20 20 -20 20 -20 20]); F(j) = getframe; end movie(F,4)

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  • .Net Remote Log Querying

    - by jlafay
    I have a Win Service that I'm working on that consists of the service, WF Service (using WorkflowServiceHost), a Workflow (WorkflowApplication) that queries/processes data from a SQL Server DB, and a Comm Marshall class that handles data flow between the service and the WF. The WF does a lot of heavy data processing and the original app (early VB6) logged all the processing and displayed the results on the screen of the host machine. Critical events will be committed to eventlog because I strongly believe that should be common practice because admins naturally will look there and because it already has support for remote viewing. The workflow will also need to write logging events as it processes and iterates according to our business logic. Such as: records queried, records returned, processed records, etc. The data is very critical and we need to log actions as they occur. The logs are currently kept as text files on disk and I think that is ok. Ideally I would like to record log events in XML so it's easier to query and because it is less costly than a DB, especially since our DB servers do a lot of heavy processing anyways. Since we are replacing essentially a VB6 application with a robust windows service (taking advantage of WF 4.0), it has been requested that a remote client also be created. It receives callbacks from the service after subscribing to it and being added to a collection of subscribers. Basic statistics and summaries are updated client side after receiving basic monitoring data of what is going on with the service. We would like to also provide a way to provide details when we need to examine what is going on further because this is a long running data processing service and issues need to be addressed immediately. What is the best way to implement some type of query from the client that is sent to the service and returned to the client? Would it be efficient to implement another method to expose on the service and then have that pass that off to some querying class/object to examine the XML files by whichever specification and then return it to the client? That's the main concern. I don't want the service to processing to bottleneck much while this occurs. It seems that WF already auto-magically threads well for the most part but I want to make sure this is the right way to go about it. Any suggestions/recommendations on how to architect and implement a small log querying framework for a remote service would be awesome.

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