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  • Representing server state with a metric

    - by Sal
    I'm using Microsoft's Performance Monitor to dump logs of RAM, CPU, network, and disk usage from multiple servers. I'd like to get a single metric that captures the state of a given variable to a good extent. For instance, disk usage is pretty stable, so if I take a single reading that says I have 50% remaining disk space, that reading will give me an accurate measure for the day. (The servers aren't doing heavy IO writing.) However, the tricky part here is monitoring CPU and network usage. The logs currently dump the % CPU usage every ten seconds. If I take a straight average of the numbers, it may not represent reality, as % CPU will be much lower during the night than day. (We host websites that sell appliance items.) I'd like to get an average over a span during peak hours (about 5 hours in the day) and present a daily peak hour metric. Of course, there are most likely some readings that will come in as overly spiked (if multiple users pinged the server at once) or no use (a momentary idle state). Is there a standard distribution/test industries use in these situation?

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  • Removing a device in "removed" state from Linux software RAID array

    - by Sahasranaman MS
    My workstation has two disks(/dev/sd[ab]), both with similar partitioning. /dev/sdb failed, and cat /proc/mdstat stopped showing the second sdb partition. I ran mdadm --fail and mdadm --remove for all partitions from the failed disk on the arrays that use them, although all such commands failed with mdadm: set device faulty failed for /dev/sdb2: No such device mdadm: hot remove failed for /dev/sdb2: No such device or address Then I hot swapped the failed disk, partitioned the new disk and added the partitions to the respective arrays. All arrays got rebuilt properly except one, because in /dev/md2, the failed disk doesn't seem to have been removed from the array properly. Because of this, the new partition keeps getting added as a spare to the partition, and its status remains degraded. Here's what mdadm --detail /dev/md2 shows: [root@ldmohanr ~]# mdadm --detail /dev/md2 /dev/md2: Version : 1.1 Creation Time : Tue Dec 27 22:55:14 2011 Raid Level : raid1 Array Size : 52427708 (50.00 GiB 53.69 GB) Used Dev Size : 52427708 (50.00 GiB 53.69 GB) Raid Devices : 2 Total Devices : 2 Persistence : Superblock is persistent Intent Bitmap : Internal Update Time : Fri Nov 23 14:59:56 2012 State : active, degraded Active Devices : 1 Working Devices : 2 Failed Devices : 0 Spare Devices : 1 Name : ldmohanr.net:2 (local to host ldmohanr.net) UUID : 4483f95d:e485207a:b43c9af2:c37c6df1 Events : 5912611 Number Major Minor RaidDevice State 0 8 2 0 active sync /dev/sda2 1 0 0 1 removed 2 8 18 - spare /dev/sdb2 To remove a disk, mdadm needs a device filename, which was /dev/sdb2 originally, but that no longer refers to device number 1. I need help with removing device number 1 with 'removed' status and making /dev/sdb2 active.

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  • Connections to IIS sometimes get stuck in CLOSE_WAIT state

    - by randomhuman
    Our application includes an ASP.Net web service that only needs to deal with a handful of clients. As such, the 10 incoming connection limit of Windows XP Pro is generally not a problem. However, on one particular server, connections are occasionally becoming stuck in the CLOSE_WAIT state. These connections build up over time and eventually new client connections are refused because the maximum number of connections are used up. From my googling it sounds like a failure of the webservice to properly close the connection can cause this problem, but as it works just fine on hundreds of other Windows XP pro machines I can't see it being a bug in our code. It also ran fine on the affected machine until some shenanigans on the part of the end user (I think they set about deleting duplicate files in order to reduce their disk usage, but they did not exactly come clean about it). What could the user have changed to introduce this problem? Is there any way I can force connections that are in CLOSE_WAIT to time out rather than letting them hang around? I have seen suggestions to reduce TcpTimedWaitDelay, but that only relates to the TIME_WAIT state, and changing it did not have any effect.

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  • Handling null values and missing object properties in Silverlight 4

    - by PeterTweed
    Before Silverlight 4 to bind a data object to the UI and display a message associated with either a null value or if the binding path was wrong, you would need to write a Converter.  In Silverlight 4 we find the addition of the markup extensions TargetNullValue and FallbackValue that allows us to display a value when a null value is found in the bound to property and display a value when the property being bound to is not found. This post will show you how to use both markup extensions. Steps: 1. Create a new Silverlight 4 application 2. In the body of the MainPage.xaml.cs file replace the MainPage class with the following code:     public partial class MainPage : UserControl     {         public MainPage()         {             InitializeComponent();             this.Loaded += new RoutedEventHandler(MainPage_Loaded);         }           void MainPage_Loaded(object sender, RoutedEventArgs e)         {             person p = new person() { NameValue = "Peter Tweed" };             this.DataContext = p;         }     }       public class person     {         public string NameValue { get; set; }         public string TitleValue { get; set; }     } This code defines a class called person with two properties.  A new instance of the class is created, only defining the value for one of the properties and bound to the DataContext of the page. 3.  In the MainPage.xaml file copy the following XAML into the LayoutRoot grid:         <Grid.RowDefinitions>             <RowDefinition Height="60*" />             <RowDefinition Height="28*" />             <RowDefinition Height="28*" />             <RowDefinition Height="30*" />             <RowDefinition Height="154*" />         </Grid.RowDefinitions>         <Grid.ColumnDefinitions>             <ColumnDefinition Width="86*" />             <ColumnDefinition Width="314*" />         </Grid.ColumnDefinitions>         <TextBlock Grid.Row="1" Height="23" HorizontalAlignment="Left" Margin="32,0,0,0" Name="textBlock1" Text="Name Value:" VerticalAlignment="Top" />         <TextBlock Grid.Row="2" Height="23" HorizontalAlignment="Left" Margin="32,0,0,0" Name="textBlock2" Text="Title Value:" VerticalAlignment="Top" />         <TextBlock Grid.Row="3" Height="23" HorizontalAlignment="Left" Margin="32,0,0,0" Name="textBlock3" Text="Non Existant Value:" VerticalAlignment="Top" />         <TextBlock Grid.Column="1" Grid.Row="1" Height="23" HorizontalAlignment="Left" Name="textBlock4" Text="{Binding NameValue, TargetNullValue='No Name!!!!!!!'}" VerticalAlignment="Top" Margin="6,0,0,0" />         <TextBlock Grid.Column="1" Grid.Row="2" Height="23" HorizontalAlignment="Left" Name="textBlock5" Text="{Binding TitleValue, TargetNullValue='No Title!!!!!!!'}" VerticalAlignment="Top" Margin="6,0,0,0" />         <TextBlock Grid.Column="1" Grid.Row="3" Height="23" HorizontalAlignment="Left" Margin="6,0,0,0" Name="textBlock6" Text="{Binding AgeValue, FallbackValue='No such property!'}" VerticalAlignment="Top" />    This XAML defines three textblocks – two of which use the TargetNull and one that uses the FallbackValue markup extensions.  4. Run the application and see the person name displayed as defined for the person object, the expected string displayed for the TargetNullValue when no value exists for the boudn property and the expected string displayed for the FallbackValue when the property bound to is not found on the bound object. It's that easy!

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  • OpenGL Fast-Object Instancing Error

    - by HJ Media Studios
    I have some code that loops through a set of objects and renders instances of those objects. The list of objects that needs to be rendered is stored as a std::map, where an object of class MeshResource contains the vertices and indices with the actual data, and an object of classMeshRenderer defines the point in space the mesh is to be rendered at. My rendering code is as follows: glDisable(GL_BLEND); glEnable(GL_CULL_FACE); glDepthMask(GL_TRUE); glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT); glEnable(GL_DEPTH_TEST); for (std::map<MeshResource*, std::vector<MeshRenderer*> >::iterator it = renderables.begin(); it != renderables.end(); it++) { it->first->setupBeforeRendering(); cout << "<"; for (unsigned long i =0; i < it->second.size(); i++) { //Pass in an identity matrix to the vertex shader- used here only for debugging purposes; the real code correctly inputs any matrix. uniformizeModelMatrix(Matrix4::IDENTITY); /** * StartHere fix rendering problem. * Ruled out: * Vertex buffers correctly. * Index buffers correctly. * Matrices correct? */ it->first->render(); } it->first->cleanupAfterRendering(); } geometryPassShader->disable(); glDepthMask(GL_FALSE); glDisable(GL_CULL_FACE); glDisable(GL_DEPTH_TEST); The function in MeshResource that handles setting up the uniforms is as follows: void MeshResource::setupBeforeRendering() { glEnableVertexAttribArray(0); glEnableVertexAttribArray(1); glEnableVertexAttribArray(2); glEnableVertexAttribArray(3); glEnableVertexAttribArray(4); glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, iboID); glBindBuffer(GL_ARRAY_BUFFER, vboID); glVertexAttribPointer(0, 3, GL_FLOAT, GL_FALSE, sizeof(Vertex), 0); // Vertex position glVertexAttribPointer(1, 3, GL_FLOAT, GL_FALSE, sizeof(Vertex), (const GLvoid*) 12); // Vertex normal glVertexAttribPointer(2, 2, GL_FLOAT, GL_FALSE, sizeof(Vertex), (const GLvoid*) 24); // UV layer 0 glVertexAttribPointer(3, 3, GL_FLOAT, GL_FALSE, sizeof(Vertex), (const GLvoid*) 32); // Vertex color glVertexAttribPointer(4, 1, GL_UNSIGNED_SHORT, GL_FALSE, sizeof(Vertex), (const GLvoid*) 44); //Material index } The code that renders the object is this: void MeshResource::render() { glDrawElements(GL_TRIANGLES, geometry->numIndices, GL_UNSIGNED_SHORT, 0); } And the code that cleans up is this: void MeshResource::cleanupAfterRendering() { glDisableVertexAttribArray(0); glDisableVertexAttribArray(1); glDisableVertexAttribArray(2); glDisableVertexAttribArray(3); glDisableVertexAttribArray(4); } The end result of this is that I get a black screen, although the end of my rendering pipeline after the rendering code (essentially just drawing axes and lines on the screen) works properly, so I'm fairly sure it's not an issue with the passing of uniforms. If, however, I change the code slightly so that the rendering code calls the setup immediately before rendering, like so: void MeshResource::render() { setupBeforeRendering(); glDrawElements(GL_TRIANGLES, geometry->numIndices, GL_UNSIGNED_SHORT, 0); } The program works as desired. I don't want to have to do this, though, as my aim is to set up vertex, material, etc. data once per object type and then render each instance updating only the transformation information. The uniformizeModelMatrix works as follows: void RenderManager::uniformizeModelMatrix(Matrix4 matrix) { glBindBuffer(GL_UNIFORM_BUFFER, globalMatrixUBOID); glBufferSubData(GL_UNIFORM_BUFFER, 0, sizeof(Matrix4), matrix.ptr()); glBindBuffer(GL_UNIFORM_BUFFER, 0); }

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  • Web workflow solution - how should I approach the design?

    - by Tom Pickles
    We've been tasked with creating a web based workflow tool to track change management. It has a single workflow with multiple synchronous tasks for the most part, but branch out at a point to tasks running in parallel which meet up later on. There will be all sorts of people using the application, and all of them will need to see their outstanding tasks for each change, but only theirs, not others. There will also be a high level group of people who oversee all changes, so need to see everything. They will need to see tasks which have not been done in the specified time, who's responsible etc. The data will be persisted to a SQL database. It'll all be put together using .Net. I've been trying to learn and implement OOP into my designs of late, but I'm wondering if this is moot in this instance as it may be better to have the business logic for this in stored procedures in the DB. I could use POCO's, a front end layer and a data access layer for the web application and just use it as a mechanism for CRUD actions on the DB, then use SP's fired in the DB to apply the business rules. On the other hand, I could use an object oriented design within the web app, but as the data in the app is state-less, is this a bad idea? I could try and model out the whole application into a class structure, implementing interfaces, base classes and all that good stuff. So I would create a change class, which contained a list of task classes/types, which defined each task, and implement an ITask interface etc. Put end-user types into the tasks to identify who should be doing what task. Then apply all the business logic in the respective class methods etc. What approach do you guys think I should be using for this solution?

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  • Getting rid of Massive View Controller in iOS?

    - by Earl Grey
    I had a discussion with my colleague about the following problem. We have an application where we need filtering functionality. On any main screen within the upper navigation bar, there is a button in the upper right corner. Once you touch that button, an custom written Alert View like view will pop up modally, behind it a semitransparent black overlay view. In that modal view, there is a table view of options, and you can choose one exclusively. Based on your selection, once this modal view is closed, the list of items in the main view is filtered. It is simply a modally presented filter to filter the main table view.This UI design is dictated by the design department, I cannot do anything about it so let accept this as a premise. Also the main filter button in the navbar will change colours to indicate that the filter is active. The question I have is about implementation. I suggested to my colleague that we create a separate XYZFilter class that will be an instance created by the main view controller acquire the filtering options handle saving and restoration of its state - i.e. last filter selected provide its two views - the overlay view and the modal view be the datasource for the table in its modal view. For some unknown reason, my colleague was not impressed by that approach at all. He simply wants to do these functionalities in the main view controller, maybe out of being used to do this in the past like that :-/ Is there any fundamental problem with my approach? I want to keep the view controller small, not to have spaghetti code create a reusable component (for use outside the project) have more object oriented, decoupled approach. prevent duplication of code as we need the filtering in two different places but it looks the same in both.. Any advice?

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  • Explanation on how "Tell, Don't Ask" is considered good OO

    - by Pubby
    This blogpost was posted on Hacker News with several upvotes. Coming from C++, most of these examples seem to go against what I've been taught. Such as example #2: Bad: def check_for_overheating(system_monitor) if system_monitor.temperature > 100 system_monitor.sound_alarms end end versus good: system_monitor.check_for_overheating class SystemMonitor def check_for_overheating if temperature > 100 sound_alarms end end end The advice in C++ is that you should prefer free functions instead of member functions as they increase encapsulation. Both of these are identical semantically, so why prefer the choice that has access to more state? Example 4: Bad: def street_name(user) if user.address user.address.street_name else 'No street name on file' end end versus good: def street_name(user) user.address.street_name end class User def address @address || NullAddress.new end end class NullAddress def street_name 'No street name on file' end end Why is it the responsibility of User to format an unrelated error string? What if I want to do something besides print 'No street name on file' if it has no street? What if the street is named the same thing? Could someone enlighten me on the "Tell, Don't Ask" advantages and rationale? I am not looking for which is better, but instead trying to understand the author's viewpoint.

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  • FP for simulation and modelling

    - by heaptobesquare
    I'm about to start a simulation/modelling project. I already know that OOP is used for this kind of projects. However, studying Haskell made me consider using the FP paradigm for modelling a system of components. Let me elaborate: Let's say I have a component of type A, characterised by a set of data (a parameter like temperature or pressure,a PDE and some boundary conditions,etc.) and a component of type B, characterised by a different set of data(different or same parameter, different PDE and boundary conditions). Let's also assume that the functions/methods that are going to be applied on each component are the same (a Galerkin method for example). If I were to use an OOP approach, I would create two objects that would encapsulate each type's data, the methods for solving the PDE(inheritance would be used here for code reuse) and the solution to the PDE. On the other hand, if I were to use an FP approach, each component would be broken down to data parts and the functions that would act upon the data in order to get the solution for the PDE. This approach seems simpler to me assuming that linear operations on data would be trivial and that the parameters are constant. What if the parameters are not constant(for example, temperature increases suddenly and therefore cannot be immutable)? In OOP, the object's (mutable) state can be used. I know that Haskell has Monads for that. To conclude, would implementing the FP approach be actually simpler,less time consuming and easier to manage (add a different type of component or new method to solve the pde) compared to the OOP one? I come from a C++/Fortran background, plus I'm not a professional programmer, so correct me on anything that I've got wrong.

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  • Design suggestions needed to create a MathBuilder framework

    - by Darf Zon
    Let explain what I'm trying to create. I'm creating a framework, the idea is to provide base classes to generate a math problem. Why do I need this framework? Because at first time, I realized when I create a new math problem I always do the same steps. Configuration settings such range numbers. For example if I'm developing multiplications, in beginner level only generate the first number between 2-5 or in advanced level, the first number will be between 6- 9, for example. Generate problem method. All the time I need to invoke a method like this to generate the problem. This one receives the configuration settings and generate the number according to them. And generate the object with the respective data. Validate the problem. Sometimes the problem generated is not valid. For example, supposed I'm creating fractions in most simplified, if I receive 2/4, the program should detect that this is not valid and must generate another like this one, 1/4. Load the view. All of them, have a custom view (please watch below the images). All of the problems must know how to CHECK if the user result is correct. All of this problems has answers. Some of them just require one answer, anothers may require more than one, so I guess a way to maintain flexibility to the developer has all the answers he wanna used. At the beginning I started using PRISM. Generate modules for each math problem was the idea and load it in the main system. I guess are the most important things of this idea. Let me showing some problems which I create in a WPF standalone program. Here I have a math problem about areas. When I generate the problem a set to the view the object and it draw it. In beginner level, I set in the configuration settings that just load square types. But in advance level, can load triangles and squares randomly. In this another, generate a binary problem like addition, subtraction, multiplication or division. Above just generate a single problem. The idea of this is to show a test o quiz, I mean get a worksheet (this I call as a collection of problems) where the user can answer it. I hope gets the idea with my ugly drawing. How to load this math problems? As I said above, I started using PRISM, and each module contains a math problem kind. This is a snapshot of my first demo. Below show the modules loaded, and center the respective configurations or levels. Until momment, I have no idea to start creating this software. I just know that I need a question | problem class, response class, user class. But I get lost about what properties should have to contain in it. Please give a little hand of this framework. I put much effort on this question, so if any isn't clear, let me know to clarify it.

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  • Starting to create a MathBuilder framework, help to start creating the design

    - by Darf Zon
    Let explain what I'm trying to create. I'm creating a framework, the idea is to provide base classes to generate a math problem. Why do I need this framework? Because at first time, I realized when I create a new math problem I always do the same steps. Configuration settings such range numbers. For example if I'm developing multiplications, in beginner level only generate the first number between 2-5 or in advanced level, the first number will be between 6- 9, for example. Generate problem method. All the time I need to invoke a method like this to generate the problem. This one receives the configuration settings and generate the number according to them. And generate the object with the respective data. Validate the problem. Sometimes the problem generated is not valid. For example, supposed I'm creating fractions in most simplified, if I receive 2/4, the program should detect that this is not valid and must generate another like this one, 1/4. Load the view. All of them, have a custom view (please watch below the images). All of the problems must know how to CHECK if the user result is correct. All of this problems has answers. Some of them just require one answer, anothers may require more than one, so I guess a way to maintain flexibility to the developer has all the answers he wanna used. At the beginning I started using PRISM. Generate modules for each math problem was the idea and load it in the main system. I guess are the most important things of this idea. Let me showing some problems which I create in a WPF standalone program. Here I have a math problem about areas. When I generate the problem a set to the view the object and it draw it. In beginner level, I set in the configuration settings that just load square types. But in advance level, can load triangles and squares randomly. In this another, generate a binary problem like addition, subtraction, multiplication or division. Above just generate a single problem. The idea of this is to show a test o quiz, I mean get a worksheet (this I call as a collection of problems) where the user can answer it. I hope gets the idea with my ugly drawing. How to load this math problems? As I said above, I started using PRISM, and each module contains a math problem kind. This is a snapshot of my first demo. Below show the modules loaded, and center the respective configurations or levels. Until momment, I have no idea to start creating this software. I just know that I need a question | problem class, response class, user class. But I get lost about what properties should have to contain in it. Please give a little hand of this framework. I put much effort on this question, so if any isn't clear, let me know to clarify it.

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  • Why is there no service-oriented language?

    - by Wolfgang
    Edit: To avoid further confusion: I am not talking about web services and such. I am talking about structuring applications internally, it's not about how computers communicate. It's about programming languages, compilers and how the imperative programming paradigm is extended. Original: In the imperative programming field, we saw two paradigms in the past 20 years (or more): object-oriented (OO), and service-oriented (SO) aka. component-based (CB). Both paradigms extend the imperative programming paradigm by introducing their own notion of modules. OO calls them objects (and classes) and lets them encapsulates both data (fields) and procedures (methods) together. SO, in contrast, separates data (records, beans, ...) from code (components, services). However, only OO has programming languages which natively support its paradigm: Smalltalk, C++, Java and all other JVM-compatibles, C# and all other .NET-compatibles, Python etc. SO has no such native language. It only comes into existence on top of procedural languages or OO languages: COM/DCOM (binary, C, C++), CORBA, EJB, Spring, Guice (all Java), ... These SO frameworks clearly suffer from the missing native language support of their concepts. They start using OO classes to represent services and records. This leads to designs where there is a clear distinction between classes that have methods only (services) and those that have fields only (records). Inheritance between services or records is then simulated by inheritance of classes. Technically, its not kept so strictly but in general programmers are adviced to make classes to play only one of the two roles. They use additional, external languages to represent the missing parts: IDL's, XML configurations, Annotations in Java code, or even embedded DSL like in Guice. This is especially needed, but not limited to, since the composition of services is not part of the service code itself. In OO, objects create other objects so there is no need for such facilities but for SO there is because services don't instantiate or configure other services. They establish an inner-platform effect on top of OO (early EJB, CORBA) where the programmer has to write all the code that is needed to "drive" SO. Classes represent only a part of the nature of a service and lots of classes have to be written to form a service together. All that boiler plate is necessary because there is no SO compiler which would do it for the programmer. This is just like some people did it in C for OO when there was no C++. You just pass the record which holds the data of the object as a first parameter to the procedure which is the method. In a OO language this parameter is implicit and the compiler produces all the code that we need for virtual functions etc. For SO, this is clearly missing. Especially the newer frameworks extensively use AOP or introspection to add the missing parts to a OO language. This doesn't bring the necessary language expressiveness but avoids the boiler platform code described in the previous point. Some frameworks use code generation to produce the boiler plate code. Configuration files in XML or annotations in OO code is the source of information for this. Not all of the phenomena that I mentioned above can be attributed to SO but I hope it clearly shows that there is a need for a SO language. Since this paradigm is so popular: why isn't there one? Or maybe there are some academic ones but at least the industry doesn't use one.

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  • What are the disadvantages of self-encapsulation?

    - by Dave Jarvis
    Background Tony Hoare's billion dollar mistake was the invention of null. Subsequently, a lot of code has become riddled with null pointer exceptions (segfaults) when software developers try to use (dereference) uninitialized variables. In 1989, Wirfs-Brock and Wikerson wrote: Direct references to variables severely limit the ability of programmers to re?ne existing classes. The programming conventions described here structure the use of variables to promote reusable designs. We encourage users of all object-oriented languages to follow these conventions. Additionally, we strongly urge designers of object-oriented languages to consider the effects of unrestricted variable references on reusability. Problem A lot of software, especially in Java, but likely in C# and C++, often uses the following pattern: public class SomeClass { private String someAttribute; public SomeClass() { this.someAttribute = "Some Value"; } public void someMethod() { if( this.someAttribute.equals( "Some Value" ) ) { // do something... } } public void setAttribute( String s ) { this.someAttribute = s; } public String getAttribute() { return this.someAttribute; } } Sometimes a band-aid solution is used by checking for null throughout the code base: public void someMethod() { assert this.someAttribute != null; if( this.someAttribute.equals( "Some Value" ) ) { // do something... } } public void anotherMethod() { assert this.someAttribute != null; if( this.someAttribute.equals( "Some Default Value" ) ) { // do something... } } The band-aid does not always avoid the null pointer problem: a race condition exists. The race condition is mitigated using: public void anotherMethod() { String someAttribute = this.someAttribute; assert someAttribute != null; if( someAttribute.equals( "Some Default Value" ) ) { // do something... } } Yet that requires two statements (assignment to local copy and check for null) every time a class-scoped variable is used to ensure it is valid. Self-Encapsulation Ken Auer's Reusability Through Self-Encapsulation (Pattern Languages of Program Design, Addison Wesley, New York, pp. 505-516, 1994) advocated self-encapsulation combined with lazy initialization. The result, in Java, would resemble: public class SomeClass { private String someAttribute; public SomeClass() { setAttribute( "Some Value" ); } public void someMethod() { if( getAttribute().equals( "Some Value" ) ) { // do something... } } public void setAttribute( String s ) { this.someAttribute = s; } public String getAttribute() { String someAttribute = this.someAttribute; if( someAttribute == null ) { setAttribute( createDefaultValue() ); } return someAttribute; } protected String createDefaultValue() { return "Some Default Value"; } } All duplicate checks for null are superfluous: getAttribute() ensures the value is never null at a single location within the containing class. Efficiency arguments should be fairly moot -- modern compilers and virtual machines can inline the code when possible. As long as variables are never referenced directly, this also allows for proper application of the Open-Closed Principle. Question What are the disadvantages of self-encapsulation, if any? (Ideally, I would like to see references to studies that contrast the robustness of similarly complex systems that use and don't use self-encapsulation, as this strikes me as a fairly straightforward testable hypothesis.)

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  • Is my class structure good enough?

    - by Rivten
    So I wanted to try out this challenge on reddit which is mostly about how you structure your data the best you can. I decided to challenge my C++ skills. Here's how I planned this. First, there's the Game class. It deals with time and is the only class main has access to. A game has a Forest. For now, this class does not have a lot of things, only a size and a Factory. Will be put in better use when it will come to SDL-stuff I guess A Factory is the thing that deals with the Game Objects (a.k.a. Trees, Lumberjack and Bears). It has a vector of all GameObjects and a queue of Events which will be managed at the end of one month. A GameObject is an abstract class which can be updated and which can notify the Event Listener The EventListener is a class which handles all the Events of a simulation. It can recieve events from a Game Object and notify the Factory if needed, the latter will manage correctly the event. So, the Tree, Lumberjack and Bear classes all inherits from GameObject. And Sapling and Elder Tree inherits from Tree. Finally, an Event is defined by an event_type enumeration (LUMBERJACK_MAWED, SAPPLING_EVOLUTION, ...) and an event_protagonists union (a GameObject or a pair of GameObject (who killed who ?)). I was quite happy at first with this because it seems quite logic and flexible. But I ended up questionning this structure. Here's why : I dislike the fact that a GameObject need to know about the Factory. Indeed, when a Bear moves somewhere, it needs to know if there's a Lumberjack ! Or it is the Factory which handles places and objects. It would be great if a GameObject could only interact with the EventListener... or maybe it's not that much of a big deal. Wouldn't it be better if I separate the Factory in three vectors ? One for each kind of GameObject. The idea would be to optimize research. If I'm looking do delete a dead lumberjack, I would only have to look in one shorter vector rather than a very long vector. Another problem arises when I want to know if there is any particular object in a given case because I have to look for all the gameObjects and see if they are at the given case. I would tend to think that the other idea would be to use a matrix but then the issue would be that I would have empty cases (and therefore unused space). I don't really know if Sapling and Elder Tree should inherit from Tree. Indeed, a Sapling is a Tree but what about its evolution ? Should I just delete the sapling and say to the factory to create a new Tree at the exact same place ? It doesn't seem natural to me to do so. How could I improve this ? Is the design of an Event quite good ? I've never used unions before in C++ but I didn't have any other ideas about what to use. Well, I hope I have been clear enough. Thank you for taking the time to help me !

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  • Nginx and client certificates from hierarchical OpenSSL-based certification authorities

    - by Fmy Oen
    I'm trying to set up root certification authority, subordinate certification authority and to generate the client certificates signed by any of this CA that nginx 0.7.67 on Debian Squeeze will accept. My problem is that root CA signed client certificate works fine while subordinate CA signed one results in "400 Bad Request. The SSL certificate error". Step 1: nginx virtual host configuration: server { server_name test.local; access_log /var/log/nginx/test.access.log; listen 443 default ssl; keepalive_timeout 70; ssl_protocols SSLv3 TLSv1; ssl_ciphers AES128-SHA:AES256-SHA:RC4-SHA:DES-CBC3-SHA:RC4-MD5; ssl_certificate /etc/nginx/ssl/server.crt; ssl_certificate_key /etc/nginx/ssl/server.key; ssl_client_certificate /etc/nginx/ssl/client.pem; ssl_verify_client on; ssl_session_cache shared:SSL:10m; ssl_session_timeout 5m; location / { proxy_pass http://testsite.local/; } } Step 2: PKI infrastructure organization for both root and subordinate CA (based on this article): # mkdir ~/pki && cd ~/pki # mkdir rootCA subCA # cp -v /etc/ssl/openssl.cnf rootCA/ # cd rootCA/ # mkdir certs private crl newcerts; touch serial; echo 01 > serial; touch index.txt; touch crlnumber; echo 01 > crlnumber # cp -Rvp * ../subCA/ Almost no changes was made to rootCA/openssl.cnf: [ CA_default ] dir = . # Where everything is kept ... certificate = $dir/certs/rootca.crt # The CA certificate ... private_key = $dir/private/rootca.key # The private key and to subCA/openssl.cnf: [ CA_default ] dir = . # Where everything is kept ... certificate = $dir/certs/subca.crt # The CA certificate ... private_key = $dir/private/subca.key # The private key Step 3: Self-signed root CA certificate generation: # openssl genrsa -out ./private/rootca.key -des3 2048 # openssl req -x509 -new -key ./private/rootca.key -out certs/rootca.crt -config openssl.cnf Enter pass phrase for ./private/rootca.key: You are about to be asked to enter information that will be incorporated into your certificate request. What you are about to enter is what is called a Distinguished Name or a DN. There are quite a few fields but you can leave some blank For some fields there will be a default value, If you enter '.', the field will be left blank. ----- Country Name (2 letter code) [AU]: State or Province Name (full name) [Some-State]: Locality Name (eg, city) []: Organization Name (eg, company) [Internet Widgits Pty Ltd]: Organizational Unit Name (eg, section) []: Common Name (eg, YOUR name) []:rootca Email Address []: Step 4: Subordinate CA certificate generation: # cd ../subCA # openssl genrsa -out ./private/subca.key -des3 2048 # openssl req -new -key ./private/subca.key -out subca.csr -config openssl.cnf Enter pass phrase for ./private/subca.key: You are about to be asked to enter information that will be incorporated into your certificate request. What you are about to enter is what is called a Distinguished Name or a DN. There are quite a few fields but you can leave some blank For some fields there will be a default value, If you enter '.', the field will be left blank. ----- Country Name (2 letter code) [AU]: State or Province Name (full name) [Some-State]: Locality Name (eg, city) []: Organization Name (eg, company) [Internet Widgits Pty Ltd]: Organizational Unit Name (eg, section) []: Common Name (eg, YOUR name) []:subca Email Address []: Please enter the following 'extra' attributes to be sent with your certificate request A challenge password []: An optional company name []: Step 5: Subordinate CA certificate signing by root CA certificate: # cd ../rootCA/ # openssl ca -in ../subCA/subca.csr -extensions v3_ca -config openssl.cnf Using configuration from openssl.cnf Enter pass phrase for ./private/rootca.key: Check that the request matches the signature Signature ok Certificate Details: Serial Number: 1 (0x1) Validity Not Before: Feb 4 10:49:43 2013 GMT Not After : Feb 4 10:49:43 2014 GMT Subject: countryName = AU stateOrProvinceName = Some-State organizationName = Internet Widgits Pty Ltd commonName = subca X509v3 extensions: X509v3 Subject Key Identifier: C9:E2:AC:31:53:81:86:3F:CD:F8:3D:47:10:FC:E5:8E:C2:DA:A9:20 X509v3 Authority Key Identifier: keyid:E9:50:E6:BF:57:03:EA:6E:8F:21:23:86:BB:44:3D:9F:8F:4A:8B:F2 DirName:/C=AU/ST=Some-State/O=Internet Widgits Pty Ltd/CN=rootca serial:9F:FB:56:66:8D:D3:8F:11 X509v3 Basic Constraints: CA:TRUE Certificate is to be certified until Feb 4 10:49:43 2014 GMT (365 days) Sign the certificate? [y/n]:y 1 out of 1 certificate requests certified, commit? [y/n]y ... # cd ../subCA/ # cp -v ../rootCA/newcerts/01.pem certs/subca.crt Step 6: Server certificate generation and signing by root CA (for nginx virtual host): # cd ../rootCA # openssl genrsa -out ./private/server.key -des3 2048 # openssl req -new -key ./private/server.key -out server.csr -config openssl.cnf Enter pass phrase for ./private/server.key: You are about to be asked to enter information that will be incorporated into your certificate request. What you are about to enter is what is called a Distinguished Name or a DN. There are quite a few fields but you can leave some blank For some fields there will be a default value, If you enter '.', the field will be left blank. ----- Country Name (2 letter code) [AU]: State or Province Name (full name) [Some-State]: Locality Name (eg, city) []: Organization Name (eg, company) [Internet Widgits Pty Ltd]: Organizational Unit Name (eg, section) []: Common Name (eg, YOUR name) []:test.local Email Address []: Please enter the following 'extra' attributes to be sent with your certificate request A challenge password []: An optional company name []: # openssl ca -in server.csr -out certs/server.crt -config openssl.cnf Step 7: Client #1 certificate generation and signing by root CA: # openssl genrsa -out ./private/client1.key -des3 2048 # openssl req -new -key ./private/client1.key -out client1.csr -config openssl.cnf Enter pass phrase for ./private/client1.key: You are about to be asked to enter information that will be incorporated into your certificate request. What you are about to enter is what is called a Distinguished Name or a DN. There are quite a few fields but you can leave some blank For some fields there will be a default value, If you enter '.', the field will be left blank. ----- Country Name (2 letter code) [AU]: State or Province Name (full name) [Some-State]: Locality Name (eg, city) []: Organization Name (eg, company) [Internet Widgits Pty Ltd]: Organizational Unit Name (eg, section) []: Common Name (eg, YOUR name) []:Client #1 Email Address []: Please enter the following 'extra' attributes to be sent with your certificate request A challenge password []: An optional company name []: # openssl ca -in client1.csr -out certs/client1.crt -config openssl.cnf Step 8: Client #1 certificate converting to PKCS12 format: # openssl pkcs12 -export -out certs/client1.p12 -inkey private/client1.key -in certs/client1.crt -certfile certs/rootca.crt Step 9: Client #2 certificate generation and signing by subordinate CA: # cd ../subCA/ # openssl genrsa -out ./private/client2.key -des3 2048 # openssl req -new -key ./private/client2.key -out client2.csr -config openssl.cnf Enter pass phrase for ./private/client2.key: You are about to be asked to enter information that will be incorporated into your certificate request. What you are about to enter is what is called a Distinguished Name or a DN. There are quite a few fields but you can leave some blank For some fields there will be a default value, If you enter '.', the field will be left blank. ----- Country Name (2 letter code) [AU]: State or Province Name (full name) [Some-State]: Locality Name (eg, city) []: Organization Name (eg, company) [Internet Widgits Pty Ltd]: Organizational Unit Name (eg, section) []: Common Name (eg, YOUR name) []:Client #2 Email Address []: Please enter the following 'extra' attributes to be sent with your certificate request A challenge password []: An optional company name []: # openssl ca -in client2.csr -out certs/client2.crt -config openssl.cnf Step 10: Client #2 certificate converting to PKCS12 format: # openssl pkcs12 -export -out certs/client2.p12 -inkey private/client2.key -in certs/client2.crt -certfile certs/subca.crt Step 11: Passing server certificate and private key to nginx (performed with OS superuser privileges): # cd ../rootCA/ # cp -v certs/server.crt /etc/nginx/ssl/ # cp -v private/server.key /etc/nginx/ssl/ Step 12: Passing root and subordinate CA certificates to nginx (performed with OS superuser privileges): # cat certs/rootca.crt > /etc/nginx/ssl/client.pem # cat ../subCA/certs/subca.crt >> /etc/nginx/ssl/client.pem client.pem file look like this: # cat /etc/nginx/ssl/client.pem -----BEGIN CERTIFICATE----- MIID6TCCAtGgAwIBAgIJAJ/7VmaN048RMA0GCSqGSIb3DQEBBQUAMFYxCzAJBgNV BAYTAkFVMRMwEQYDVQQIEwpTb21lLVN0YXRlMSEwHwYDVQQKExhJbnRlcm5ldCBX aWRnaXRzIFB0eSBMdGQxDzANBgNVBAMTBnJvb3RjYTAeFw0xMzAyMDQxMDM1NTda ... -----END CERTIFICATE----- Certificate: Data: Version: 3 (0x2) Serial Number: 1 (0x1) ... -----BEGIN CERTIFICATE----- MIID4DCCAsigAwIBAgIBATANBgkqhkiG9w0BAQUFADBWMQswCQYDVQQGEwJBVTET MBEGA1UECBMKU29tZS1TdGF0ZTEhMB8GA1UEChMYSW50ZXJuZXQgV2lkZ2l0cyBQ dHkgTHRkMQ8wDQYDVQQDEwZyb290Y2EwHhcNMTMwMjA0MTA0OTQzWhcNMTQwMjA0 ... -----END CERTIFICATE----- It looks like everything is working fine: # service nginx reload # Reloading nginx configuration: Enter PEM pass phrase: # nginx. # Step 13: Installing *.p12 certificates in browser (Firefox in my case) gives the problem I've mentioned above. Client #1 = 200 OK, Client #2 = 400 Bad request/The SSL certificate error. Any ideas what should I do? Update 1: Results of SSL connection test attempts: # openssl s_client -connect test.local:443 -CAfile ~/pki/rootCA/certs/rootca.crt -cert ~/pki/rootCA/certs/client1.crt -key ~/pki/rootCA/private/client1.key -showcerts Enter pass phrase for tmp/testcert/client1.key: CONNECTED(00000003) depth=1 C = AU, ST = Some-State, O = Internet Widgits Pty Ltd, CN = rootca verify return:1 depth=0 C = AU, ST = Some-State, O = Internet Widgits Pty Ltd, CN = test.local verify return:1 --- Certificate chain 0 s:/C=AU/ST=Some-State/O=Internet Widgits Pty Ltd/CN=test.local i:/C=AU/ST=Some-State/O=Internet Widgits Pty Ltd/CN=rootca -----BEGIN CERTIFICATE----- MIIDpjCCAo6gAwIBAgIBAjANBgkqhkiG9w0BAQUFADBWMQswCQYDVQQGEwJBVTET MBEGA1UECBMKU29tZS1TdGF0ZTEhMB8GA1UEChMYSW50ZXJuZXQgV2lkZ2l0cyBQ dHkgTHRkMQ8wDQYDVQQDEwZyb290Y2EwHhcNMTMwMjA0MTEwNjAzWhcNMTQwMjA0 ... -----END CERTIFICATE----- 1 s:/C=AU/ST=Some-State/O=Internet Widgits Pty Ltd/CN=rootca i:/C=AU/ST=Some-State/O=Internet Widgits Pty Ltd/CN=rootca -----BEGIN CERTIFICATE----- MIID6TCCAtGgAwIBAgIJAJ/7VmaN048RMA0GCSqGSIb3DQEBBQUAMFYxCzAJBgNV BAYTAkFVMRMwEQYDVQQIEwpTb21lLVN0YXRlMSEwHwYDVQQKExhJbnRlcm5ldCBX aWRnaXRzIFB0eSBMdGQxDzANBgNVBAMTBnJvb3RjYTAeFw0xMzAyMDQxMDM1NTda ... -----END CERTIFICATE----- --- Server certificate subject=/C=AU/ST=Some-State/O=Internet Widgits Pty Ltd/CN=test.local issuer=/C=AU/ST=Some-State/O=Internet Widgits Pty Ltd/CN=rootca --- Acceptable client certificate CA names /C=AU/ST=Some-State/O=Internet Widgits Pty Ltd/CN=rootca /C=AU/ST=Some-State/O=Internet Widgits Pty Ltd/CN=subca --- SSL handshake has read 3395 bytes and written 2779 bytes --- New, TLSv1/SSLv3, Cipher is AES256-SHA Server public key is 2048 bit Secure Renegotiation IS supported Compression: zlib compression Expansion: zlib compression SSL-Session: Protocol : TLSv1 Cipher : AES256-SHA Session-ID: 15BFC2029691262542FAE95A48078305E76EEE7D586400F8C4F7C516B0F9D967 Session-ID-ctx: Master-Key: 23246CF166E8F3900793F0A2561879E5DB07291F32E99591BA1CF53E6229491FEAE6858BFC9AACAF271D9C3706F139C7 Key-Arg : None PSK identity: None PSK identity hint: None SRP username: None TLS session ticket: 0000 - c2 5e 1d d2 b5 6d 40 23-b2 40 89 e4 35 75 70 07 .^...m@#[email protected]. 0010 - 1b bb 2b e6 e0 b5 ab 10-10 bf 46 6e aa 67 7f 58 ..+.......Fn.g.X 0020 - cf 0e 65 a4 67 5a 15 ba-aa 93 4e dd 3d 6e 73 4c ..e.gZ....N.=nsL 0030 - c5 56 f6 06 24 0f 48 e6-38 36 de f1 b5 31 c5 86 .V..$.H.86...1.. ... 0440 - 4c 53 39 e3 92 84 d2 d0-e5 e2 f5 8a 6a a8 86 b1 LS9.........j... Compression: 1 (zlib compression) Start Time: 1359989684 Timeout : 300 (sec) Verify return code: 0 (ok) --- Everything seems fine with Client #2 and root CA certificate but request returns 400 Bad Request error: # openssl s_client -connect test.local:443 -CAfile ~/pki/rootCA/certs/rootca.crt -cert ~/pki/subCA/certs/client2.crt -key ~/pki/subCA/private/client2.key -showcerts Enter pass phrase for tmp/testcert/client2.key: CONNECTED(00000003) depth=1 C = AU, ST = Some-State, O = Internet Widgits Pty Ltd, CN = rootca verify return:1 depth=0 C = AU, ST = Some-State, O = Internet Widgits Pty Ltd, CN = test.local verify return:1 ... Compression: 1 (zlib compression) Start Time: 1359989989 Timeout : 300 (sec) Verify return code: 0 (ok) --- GET / HTTP/1.0 HTTP/1.1 400 Bad Request Server: nginx/0.7.67 Date: Mon, 04 Feb 2013 15:00:43 GMT Content-Type: text/html Content-Length: 231 Connection: close <html> <head><title>400 The SSL certificate error</title></head> <body bgcolor="white"> <center><h1>400 Bad Request</h1></center> <center>The SSL certificate error</center> <hr><center>nginx/0.7.67</center> </body> </html> closed Verification fails with Client #2 certificate and subordinate CA certificate: # openssl s_client -connect test.local:443 -CAfile ~/pki/subCA/certs/subca.crt -cert ~/pki/subCA/certs/client2.crt -key ~/pki/subCA/private/client2.key -showcerts Enter pass phrase for tmp/testcert/client2.key: CONNECTED(00000003) depth=1 C = AU, ST = Some-State, O = Internet Widgits Pty Ltd, CN = rootca verify error:num=19:self signed certificate in certificate chain verify return:0 ... Compression: 1 (zlib compression) Start Time: 1359990354 Timeout : 300 (sec) Verify return code: 19 (self signed certificate in certificate chain) --- GET / HTTP/1.0 HTTP/1.1 400 Bad Request ... Still getting 400 Bad Request error with concatenated CA certificates and Client #2 (but still everything ok with Client #1): # cat certs/rootca.crt ../subCA/certs/subca.crt > certs/concatenatedca.crt # openssl s_client -connect test.local:443 -CAfile ~/pki/rootCA/certs/concatenatedca.crt -cert ~/pki/subCA/certs/client2.crt -key ~/pki/subCA/private/client2.key -showcerts Enter pass phrase for tmp/testcert/client2.key: CONNECTED(00000003) depth=1 C = AU, ST = Some-State, O = Internet Widgits Pty Ltd, CN = rootca verify return:1 depth=0 C = AU, ST = Some-State, O = Internet Widgits Pty Ltd, CN = test.local verify return:1 --- ... Compression: 1 (zlib compression) Start Time: 1359990772 Timeout : 300 (sec) Verify return code: 0 (ok) --- GET / HTTP/1.0 HTTP/1.1 400 Bad Request ... Update 2: I've managed to recompile nginx with enabled debug. Here is the part of successfull conection by Client #1 track: 2013/02/05 14:08:23 [debug] 38701#0: *119 accept: <MY IP ADDRESS> fd:3 2013/02/05 14:08:23 [debug] 38701#0: *119 event timer add: 3: 60000:2856497512 2013/02/05 14:08:23 [debug] 38701#0: *119 kevent set event: 3: ft:-1 fl:0025 2013/02/05 14:08:23 [debug] 38701#0: *119 malloc: 28805200:660 2013/02/05 14:08:23 [debug] 38701#0: *119 malloc: 28834400:1024 2013/02/05 14:08:23 [debug] 38701#0: *119 posix_memalign: 28860000:4096 @16 2013/02/05 14:08:23 [debug] 38701#0: *119 http check ssl handshake 2013/02/05 14:08:23 [debug] 38701#0: *119 https ssl handshake: 0x16 2013/02/05 14:08:23 [debug] 38701#0: *119 SSL server name: "test.local" 2013/02/05 14:08:23 [debug] 38701#0: *119 SSL_do_handshake: -1 2013/02/05 14:08:23 [debug] 38701#0: *119 SSL_get_error: 2 2013/02/05 14:08:23 [debug] 38701#0: *119 SSL handshake handler: 0 2013/02/05 14:08:23 [debug] 38701#0: *119 verify:1, error:0, depth:1, subject:"/C=AU /ST=Some-State/O=Internet Widgits Pty Ltd/CN=rootca",issuer: "/C=AU/ST=Some-State/O=Internet Widgits Pty Ltd/CN=rootca" 2013/02/05 14:08:23 [debug] 38701#0: *119 verify:1, error:0, depth:0, subject:"/C=AU/ST=Some-State/O=Internet Widgits Pty Ltd/CN=Client #1",issuer: "/C=AU/ST=Some-State/O=Internet Widgits Pty Ltd/CN=rootca" 2013/02/05 14:08:23 [debug] 38701#0: *119 SSL_do_handshake: 1 2013/02/05 14:08:23 [debug] 38701#0: *119 SSL: TLSv1, cipher: "AES256-SHA SSLv3 Kx=RSA Au=RSA Enc=AES(256) Mac=SHA1" 2013/02/05 14:08:23 [debug] 38701#0: *119 http process request line 2013/02/05 14:08:23 [debug] 38701#0: *119 SSL_read: -1 2013/02/05 14:08:23 [debug] 38701#0: *119 SSL_get_error: 2 2013/02/05 14:08:23 [debug] 38701#0: *119 http process request line 2013/02/05 14:08:23 [debug] 38701#0: *119 SSL_read: 1 2013/02/05 14:08:23 [debug] 38701#0: *119 SSL_read: 524 2013/02/05 14:08:23 [debug] 38701#0: *119 SSL_read: -1 2013/02/05 14:08:23 [debug] 38701#0: *119 SSL_get_error: 2 2013/02/05 14:08:23 [debug] 38701#0: *119 http request line: "GET / HTTP/1.1" And here is the part of unsuccessfull conection by Client #2 track: 2013/02/05 13:51:34 [debug] 38701#0: *112 accept: <MY_IP_ADDRESS> fd:3 2013/02/05 13:51:34 [debug] 38701#0: *112 event timer add: 3: 60000:2855488975 2013/02/05 13:51:34 [debug] 38701#0: *112 kevent set event: 3: ft:-1 fl:0025 2013/02/05 13:51:34 [debug] 38701#0: *112 malloc: 28805200:660 2013/02/05 13:51:34 [debug] 38701#0: *112 malloc: 28834400:1024 2013/02/05 13:51:34 [debug] 38701#0: *112 posix_memalign: 28860000:4096 @16 2013/02/05 13:51:34 [debug] 38701#0: *112 http check ssl handshake 2013/02/05 13:51:34 [debug] 38701#0: *112 https ssl handshake: 0x16 2013/02/05 13:51:34 [debug] 38701#0: *112 SSL server name: "test.local" 2013/02/05 13:51:34 [debug] 38701#0: *112 SSL_do_handshake: -1 2013/02/05 13:51:34 [debug] 38701#0: *112 SSL_get_error: 2 2013/02/05 13:51:34 [debug] 38701#0: *112 SSL handshake handler: 0 2013/02/05 13:51:34 [debug] 38701#0: *112 SSL_do_handshake: -1 2013/02/05 13:51:34 [debug] 38701#0: *112 SSL_get_error: 2 2013/02/05 13:51:34 [debug] 38701#0: *112 SSL handshake handler: 0 2013/02/05 13:51:34 [debug] 38701#0: *112 verify:0, error:20, depth:1, subject:"/C=AU/ST=Some-State/O=Internet Widgits Pty Ltd/CN=subca",issuer: "/C=AU/ST=Some-State/O=Internet Widgits Pty Ltd/CN=rootca" 2013/02/05 13:51:34 [debug] 38701#0: *112 verify:0, error:27, depth:1, subject:"/C=AU/ST=Some-State/O=Internet Widgits Pty Ltd/CN=subca",issuer: "/C=AU/ST=Some-State/O=Internet Widgits Pty Ltd/CN=rootca" 2013/02/05 13:51:34 [debug] 38701#0: *112 verify:1, error:27, depth:0, subject:"/C=AU/ST=Some-State/O=Internet Widgits Pty Ltd/CN=Client #2",issuer: "/C=AU/ST=Some-State/O=Internet Widgits Pty Ltd/CN=subca" 2013/02/05 13:51:34 [debug] 38701#0: *112 SSL_do_handshake: 1 2013/02/05 13:51:34 [debug] 38701#0: *112 SSL: TLSv1, cipher: "AES256-SHA SSLv3 Kx=RSA Au=RSA Enc=AES(256) Mac=SHA1" 2013/02/05 13:51:34 [debug] 38701#0: *112 http process request line 2013/02/05 13:51:34 [debug] 38701#0: *112 SSL_read: 1 2013/02/05 13:51:34 [debug] 38701#0: *112 SSL_read: 524 2013/02/05 13:51:34 [debug] 38701#0: *112 SSL_read: -1 2013/02/05 13:51:34 [debug] 38701#0: *112 SSL_get_error: 2 2013/02/05 13:51:34 [debug] 38701#0: *112 http request line: "GET / HTTP/1.1" So I'm getting OpenSSL error #20 and then #27. 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  • How to get elements from an object in C#?

    - by Drew
    I am using the AutoCompleteBox in WPF, I populate the suggestions with a List that consists of four fields. When the user selects an item and I reach my eventHandler, i can see that MyAutoCompleteBox.SelectedItem is an object that has my four values, if i hover this text in the debugger i can see the four values listed, however i don't know how to access these values in the code. I tried List<Codes> selected = MyAutoCompleteBox.SelectedItem as List<Codes>; where Codes is my List. selected returns as null and empty every time. Is there a way to get to these values? Thanks!

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  • How should I implement items that are normalized in the Database, in Object Oriented Design?

    - by Jonas
    How should I implement items that are normalized in the Database, in Object Oriented classes? In the database I have a big table of items and a smaller of groups. Each item belong to one group. This is how my database design look like: +----------------------------------------+ | Inventory | +----+------+-------+----------+---------+ | Id | Name | Price | Quantity | GroupId | +----+------+-------+----------+---------+ | 43 | Box | 34.00 | 456 | 4 | | 56 | Ball | 56.50 | 3 | 6 | | 66 | Tin | 23.00 | 14 | 4 | +----+------+-------+----------+---------+ Totally 3000 lines +----------------------+ | Groups | +---------+------+-----+ | GroupId | Name | VAT | +---------+------+-----+ | 4 | Mini | 0.2 | | 6 | Big | 0.3 | +---------+------+-----+ Totally 10 lines I will use the OOP classes in a GUI, where the user can edit Items and Groups in the inventory. It should also be easy to do calculations with a bunch of items. The group information like VAT are needed for the calculations. I will write an Item class, but do I need a Group class? and if I need it, should I keep them in a global location or how do I access it when I need it for Item-calculations? Is there any design pattern for this case?

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  • Change user control appearance based on state

    - by John
    I have a user control that consists of four overlapping items: 2 rectangles, an ellipse and a lable <UserControl x:Class="UserControl" xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation" xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml" Width="50.1" Height="45.424" Background="Transparent" FontSize="24"> <Grid> <Grid.RowDefinitions> <RowDefinition Height="3.303*" /> <RowDefinition Height="40*" /> <RowDefinition Height="2.121*" /> </Grid.RowDefinitions> <Grid.ColumnDefinitions> <ColumnDefinition Width="5.344*" /> <ColumnDefinition Width="40.075*" /> <ColumnDefinition Width="4.663*" /> </Grid.ColumnDefinitions> <Rectangle Name="Rectangle1" RadiusX="5" RadiusY="5" Fill="DarkGray" Grid.ColumnSpan="3" Grid.RowSpan="3" /> <Ellipse Name="ellipse1" Fill="{Binding State}" Margin="0.016,0.001,4.663,0" Grid.Row="1" Grid.Column="1" Grid.ColumnSpan="2" Stroke="Black" IsEnabled="True" Panel.ZIndex="2" /> <Label Name="lblNumber" HorizontalContentAlignment="Center" VerticalContentAlignment="Center" Foreground="White" FontWeight="Bold" FontSize="24" Grid.Column="1" Grid.Row="1" Padding="0" Panel.ZIndex="3">9</Label> <Rectangle Grid.Column="1" Grid.Row="1" Margin="0.091,0,4.663,0" Fill="Blue" Name="rectangle2" Stroke="Black" Grid.ColumnSpan="2" Panel.ZIndex="1" /> </Grid> Here is my business object that I want to control the state of my user control: Imports System.Data Imports System.ComponentModel Public Class BusinessObject Implements INotifyPropertyChanged 'Public logger As log4net.ILog Public Event PropertyChanged As PropertyChangedEventHandler Implements INotifyPropertyChanged.PropertyChanged Private _state As States Public Enum States State1 State2 State3 End Enum Public Property State() As States Get Return _state End Get Set(ByVal value As States) If (value <> _state) Then _state = value RaiseEvent PropertyChanged(Me, New PropertyChangedEventArgs("State")) End If End Set End Property Protected Sub OnPropertyChanged(ByVal name As String) RaiseEvent PropertyChanged(Me, New PropertyChangedEventArgs(name)) End Sub I want to be able to change the state of a business object in the code behind and have that change the colors of multiple shapes in my usercontrol. I'm not sure about how to do the binding. I set the datacontext of the user control in the code behind but not sure if that's right. I'm new to WPF and programming in general and I'm stuck on where to go from here. Any recommendations would be greatly appreciated!!

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  • What could possibly cause this error when declaring an object inside a class?

    - by M4design
    I'm battling with this assignment :) I've got two classes: Ocean and Grid. When I declare an object of the Grid inside the Ocean: unsigned int sharkCount; Grid grid; The compiler/complainer says: error C2146: syntax error : missing ';' before identifier 'grid' Can you possibly predict what produces this error with the limited info I provided? It seems that as if the Ocean doesn't like the Grid class. Could this be because of the poor implementation of the grid class. BTW the Grid has a default constructor. Yet the error happens in compiling time!. EDIT: They're each in separate header file, and I've included the Grid.h in the Ocean.h.

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  • What's The Best Object-Relational Mapping Tool For .NET?

    - by Icono123
    I've worked on a few Java web projects and we've always used Hibernate for our data object layer. I haven't worked on a large scale ASP.NET site and I'm unsure which solution to choose. I'm tempted to try NHibernate, but I don't like the fact that they use so many third party libraries. I found this list on Wikipedia of available ORM software: http://en.wikipedia.org/wiki/List_of_object-relational_mapping_software#.NET What ORM have you used? Was it easy to use? Would you recommend using it again? Was it used on a small, medium, or large project? Would you write your own? Thanks.

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  • How can I access this nested array within my JSON object?

    - by Charles
    I'm using PHP to return a json_encode()'d array for use in my Javascript code. It's being returned as: {"parent1[]":["child1","child2","child2"],"parent2[]":["child1"]} By using the following code, I am able to access parent2 > child1 $.getJSON('myfile.php', function(data) { for (var key in data) { alert(data[key]); } } However, this doesn't give me access to child1, child2, child, of parent1. Alerting the key by itself shows 'parent1' but when I try to alert it's contents, I get undefined. I figured it would give me an object/array? How do I access the children of parent1? data[key][0] ?

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