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  • Separating Db from business with Inherited classes using multiple views

    - by catalinux
    I have a software that has a car model that will be used in different views (listing, ads, detail page, carousel, up sell widget,etc). class CarModel extends DbModel{ } I look for a "nice way" (a combination of flexible, easy to maintain,etc) to have this used in views. I'm thinking at two different ways Having object views for each context CarViewBase{ var car;// of type CarModel function constructor(args){ //will instantienta internal variable car based on args } function getThumb(){ } function getTitle(){ } } CarListingView extends CarViewBase{ function getListing(){ } } CarAdsView extends CarViewBase{ //the busines rule changes for ads widget function getThumb(){ } } Extending directly the CarModel The challenges comes when My Car Model might need an abstract factory. Let's say I have a field on my car object that states the type of the car : a truck, or a bike, or van. How would affect that my object view? Let's say that getTitle() rule would be different for each type of it. How would you do it?

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  • How to get sharing options to stick - ubuntu 12.04

    - by Devin
    I'm having a really hard time trying to get my sharing set up on my 12.04 system. I've tried both desktop version and server - I'm a bit of a linux n00b, so I need a GUI, command line is beyond me and no time to learn it (not till after I get the shares setup, at least) My problem is, whenever I try to set permissions in Nautilus, it just reverts back to the default which is to "none" Basically when I choose an option... it doesn't stick. I can create shares, and it asks me if I want to add permissions automatically - but they do not stick either. When I go to look at the shared folders in Windows (or even on my Android Phone, or Mac) it gives me permissions errors and doesn't let me log in, despite me clicking "allow guest access" I have no idea what to do or where to go. I've tried searching forums and google, and I've tried everything I come across - no avail. I've even tried Mint builds to see if it's different, no change there either. Please help! I really want to setup a server to share my media files and do backups in my house. Thanks for your help!

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  • Should I use mod_wsgi embedded mode if I have full control of Apache?

    - by mgibsonbr
    I'm managing a bunch of sites and applications in a shared hosting, using Django via mod_wsgi. I had planned to use daemon mode from the beginning (to avoid restart problems), but ended up purchasing a plan that allows me to run a dedicated Apache instance. I kept using daemon mode for convenience, but I'm afraid it's consuming more server resources than it should (I have different projects for each site, each with its own process and process group), so I'm considering switching to embedded mode. Would that be a sensible thing to do? I'd still be able to restart Apache anytime I need to, and I wouldn't need so many child processes and sockets (so I hope the resource usage would decrease). But I'm unsure whether or not doing so would make it more difficult to manage those sites (if I need to update one, I have to restart all) or maybe the applications won't be properly isolated from one another. Are these problems really significant (or only a minor nuisance), are there other drawbacks I coudn't foresee? I'm looking for advice in any aspect of this setup - mainainability, performance, security etc. Tips for improving the current setup are also welcome (I know how to correctly configure a basic mod_wsgi setup, but I'm clueless about sensible values for threads, processes etc).

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  • Making a 64 bit shared library that dynamically links to a 32 bit library on Mac OS X Snow Leopard

    - by carneades
    Update: After some more reading I see that this problem is totally general, you can't mix architectures in the same process, so 64 bit Java cannot dlopen() a 32 bit library like FMOD. Is there any possible workaround for this, keeping in mind I'm writing my own C interface to the FMOD library? I need to make a 64-bit dylib on Max OS X because Java Native Access only likes 64-bit libraries on 64-bit machines. The problem is, my C source code dynamically includes FMOD which on Mac only provides 32-bit dylibs. When I try to compile without the -m32 option (since I must output a 64-bit dylib) I get the following error: gcc -dynamiclib -std=c99 -pedantic -Wall -O3 -fPIC -pthread -o ../bin/libpenntotalrecall_fmod.dylib ../../src/libpenntotalrecall_fmod.c -lfmodex -L../../lib/osx/ ld: warning: in /usr/lib/libfmodex.dylib, missing required architecture x86_64 in file Undefined symbols: "_FMOD_System_CreateSound", referenced from: _startPlayback in ccJnlwrd.o "_FMOD_Channel_GetPosition", referenced from: _streamPosition in ccJnlwrd.o "_FMOD_System_Create", referenced from: _startPlayback in ccJnlwrd.o "_FMOD_System_PlaySound", referenced from: _startPlayback in ccJnlwrd.o "_FMOD_Sound_Release", referenced from: _stopPlayback in ccJnlwrd.o "_FMOD_Channel_IsPlaying", referenced from: _playbackInProgress in ccJnlwrd.o "_FMOD_System_Update", referenced from: _streamPosition in ccJnlwrd.o _startPlayback in ccJnlwrd.o "_FMOD_Channel_SetPaused", referenced from: _startPlayback in ccJnlwrd.o "_FMOD_System_Release", referenced from: _stopPlayback in ccJnlwrd.o "_FMOD_System_Init", referenced from: _startPlayback in ccJnlwrd.o "_FMOD_Channel_SetVolume", referenced from: _startPlayback in ccJnlwrd.o "_FMOD_System_Close", referenced from: _stopPlayback in ccJnlwrd.o "_FMOD_Channel_SetCallback", referenced from: _startPlayback in ccJnlwrd.o ld: symbol(s) not found collect2: ld returned 1 exit status make: *** [all] Error 1 Shouldn't it be possible to get a 64 bit dylib from my source code that dynamically includes 32 bit libraries?!

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  • How to attach boost::shared_ptr (or another smart pointer) to reference counter of object's parent?

    - by Checkers
    I remember encountering this concept before, but can't find it in Google now. If I have an object of type A, which directly embeds an object of type B: class A { B b; }; How can I have a smart pointer to B, e. g. boost::shared_ptr<B>, but use reference count of A? Assume an instance of A itself is heap-allocated I can safely get its shared count using, say, enable_shared_from_this.

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  • Can the same DLL data be shared by 2 different processes ?

    - by Jelly Amma
    I have two different C# applications that are running at the same time. I would like both of them to be able to access the same "instance" of a DLL (also in C#). The DLL holds some data that I'd like to return to whichever of the two applications is asking for it. My DLL is thread-safe so I was hoping this would be possible but I'm not sure how. Any help or advice would be much appreciated.

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  • .NET 4.0 Dynamic object used statically?

    - by Kevin Won
    I've gotten quite sick of XML configuration files in .NET and want to replace them with a format that is more sane. Therefore, I'm writing a config file parser for C# applications that will take a custom config file format, parse it, and create a Python source string that I can then execute in C# and use as a static object (yes that's right--I want a static (not the static type dyanamic) object in the end). Here's an example of what my config file looks like: // my custom config file format GlobalName: ExampleApp Properties { ExternalServiceTimeout: "120" } Python { // this allows for straight python code to be added to handle custom config def MyCustomPython: return "cool" } Using ANTLR I've created a Lexer/Parser that will convert this format to a Python script. So assume I have that all right and can take the .config above and run my Lexer/Parser on it to get a Python script out the back (this has the added benefit of giving me a validation tool for my config). By running the resultant script in C# // simplified example of getting the dynamic python object in C# // (not how I really do it) ScriptRuntime py = Python.CreateRuntime(); dynamic conf = py.UseFile("conftest.py"); dynamic t = conf.GetConfTest("test"); I can get a dynamic object that has my configuration settings. I can now get my config file settings in C# by invoking a dynamic method on that object: //C# calling a method on the dynamic python object var timeout = t.GetProperty("ExternalServiceTimeout"); //the config also allows for straight Python scripting (via the Python block) var special = t.MyCustonPython(); of course, I have no type safety here and no intellisense support. I have a dynamic representation of my config file, but I want a static one. I know what my Python object's type is--it is actually newing up in instance of a C# class. But since it's happening in python, it's type is not the C# type, but dynamic instead. What I want to do is then cast the object back to the C# type that I know the object is: // doesn't work--can't cast a dynamic to a static type (nulls out) IConfigSettings staticTypeConfig = t as IConfigSettings Is there any way to figure out how to cast the object to the static type? I'm rather doubtful that there is... so doubtful that I took another approach of which I'm not entirely sure about. I'm wondering if someone has a better way... So here's my current tactic: since I know the type of the python object, I am creating a C# wrapper class: public class ConfigSettings : IConfigSettings that takes in a dynamic object in the ctor: public ConfigSettings(dynamic settings) { this.DynamicProxy = settings; } public dynamic DynamicProxy { get; private set; } Now I have a reference to the Python dynamic object of which I know the type. So I can then just put wrappers around the Python methods that I know are there: // wrapper access to the underlying dynamic object // this makes my dynamic object appear 'static' public string GetSetting(string key) { return this.DynamicProxy.GetProperty(key).ToString(); } Now the dynamic object is accessed through this static proxy and thus can obviously be passed around in the static C# world via interface, etc: // dependency inject the dynamic object around IBusinessLogic logic = new BusinessLogic(IConfigSettings config); This solution has the benefits of all the static typing stuff we know and love while at the same time giving me the option of 'bailing out' to dynamic too: // the DynamicProxy property give direct access to the dynamic object var result = config.DynamicProxy.MyCustomPython(); but, man, this seems rather convoluted way of getting to an object that is a static type in the first place! Since the whole dynamic/static interaction world is new to me, I'm really questioning if my solution is optimal or if I'm missing something (i.e. some way of casting that dynamic object to a known static type) about how to bridge the chasm between these two universes.

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  • Dell VRTX - slow cluster shared storage

    - by NorbyTheGeek
    I have a brand new Dell VRTX box set up as a Failover Cluster running HA Hyper-V virtual machines. This is my first time setting up clustering, and my first time with one of these boxes, so I'm sure I've missed something. The virtual machines are experiencing high disk latency and bad performance when accessing their VHD(x) files located on a Cluster Shared Volume. The VRTX has 10 x 900 GB 10K SAS drives in RAID 6 configuration, and the VRTX has the redundant Shared PERC 8 controllers. Both blades have full access to the virtual disks. There are two M520 blades installed, each with 128 GB RAM. MPIO is configured for the PERC 8 controllers. Operating system on the blades is Server 2012 (NOT R2). The RAID 6 array is split into a small (8 GB) volume for cluster quorum witness and a large (6.5 TB) volume for a Cluster Shared Volume (mounted on the nodes as C:\ClusterStorage\Volume1) An example of slow disk access: logging into a Server 2012 VM and having Server Manager come up automatically. Disk access goes to 100%, with write speeds at 20 MB or so, read speeds of 500 KB or so, and Average Response Time of over 1000 ms, sometimes spiking at 4000-5000 ms or so. It's the latency that really worries me. Is there something specific I should look at in my configuration? It doesn't seem to matter whether I use VHD or VHDX, dynamic or static.

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  • Multiple contacts with shared information

    - by Keith Thompson
    Background: I currently have several hundred contacts, synchronized between a Microsoft Exchange server and several mobile devices. I also save exported copies of the contacts in .vcf format. Is there a good way (application, file format, whatever) to maintain contacts with shared information? A very common scenario is that I have contacts for two or more people who live in the same house, for example: John Doe 123 Main Street, Anytown USA Home: 555-555-1111 Work: 555-555-2222 Mobile: 555-555-3333 E-mail: [email protected] Jane Doe 123 Main Street, Anytown USA Home: 555-555-1111 Work: 555-555-4444 Mobile: 555-555-5555 E-mail: [email protected] As you can see, both contacts have the same home address and phone number, but distinct names and work and mobile phone numbers. (Other information might also be either shared or distinct.) The applications and file formats I'm familiar with don't seem to have a good way to deal with this. If I use a single "John & Jane Doe" contact for both, it's difficult to distinguish the distinct information (if I want to call Jane's mobile phone rather than John's). If I use a separate contact for each, I have to remember to update both of them (or all of them for N 2) when they move or change their home phone number. An ideal solution would let me create a record containing information for their household, and have each of their contact records contain a reference to the household record, so that when I view John's contact record I see both shared and distinct information. Is there anything out there that has good support this kind of thing? (I would think there would be, since it's a very common scenario.) (I suppose I could roll my own system that generates merged .vcf files from some extended format, but that wouldn't play well with synchronizing across multiple devices.)

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  • Can’t connect to SQL Server 2008 - looks like Shared Memory problem

    - by user38556
    I am unable to connect to my local instance of SQL Server 2008 Express using SQL Server Management Studio. I believe the problem is related to a change I made to the connection protocols. Before the error occurred, I had Shared Memory enabled and Named Pipes and TCP/IP disabled. I then enabled both Named Pipes and TCP/IP, and this is when I started experiencing the problem. When I try to connect to the server with SSMS (with either my SQL server sysadmin login or with windows authentication), I get the following error message: A connection was successfully established with the server, but then an error occurred during the login process. (provider: Named Pipes Provider, error: 0 - No process is on the other end of the pipe.) (Microsoft SQL Server, Error: 233) Why is it returning a Named Pipes error? Why would it not just use Shared Memory, as this has a higher priority order in the list of connection protocols? It seems like it is not listening on Shared Memory for some reason? When I set Named Pipes to enabled and try to connect, I get the same error message. My windows account is does not have administrator priviliges on my computer - perhaps this is making a difference in some way (as some of the discussions in this post about an "SuperSocketNetLib\Lpc" registry key seems to suggest). I have tried restarting the SQL Server service, by the way, and also tried to get someone to log onto the machine with an admin account to restart the SQL Server service. Still no luck.

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  • Windows : Map-a-network-drive to a remote Shared-Folder (on QNAP NAS) using OpenVPN

    - by spelltox
    Provided my lack of networking knowledge, I've been struggling with this issue for quite a few days now : I have a QNAP-TS212 NAS on which i've created a shared-folder (mostly excel files). All the computers in the local network (windows) are able to access it without any problem. Now, i want to access that shared-folder remotely (windows client), so : I enabled OpenVPN (and PPTP) in QNAP admin. Installed OpenVPN on the remote client. Applied the configuration file that the QNAP generated - Configuration (openvpn.ovpn) : client dev tun script-security 3 proto udp remote ***MY_WAN_IP*** 1194 resolv-retry infinite nobind ca ca.crt auth-user-pass reneg-sec 0 cipher AES-128-CBC comp-lzo OpenVPN connect successfully from the remote client. Now, here's my problem : I can ping the NAS (got IP 10.8.0.1) from the remote client, But when i try to map-a-network-drive, i don't see the shared folder or the NAS or any of the other computers in the network... I checked - all computers are in "WORKGROUP" workgroup. I'm probably missing some basic knowledge, So - any help would be greatly appreciated ! Many thanks.

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  • Cannot Access Shared Folder From IIS

    - by Tim Scott
    From IIS I need to access a folder on another computer. Both servers are Window 2008 SP2, and they live in a Virtual Private Cloud on Amazon EC2. They reach one another by private IP -- they are in WORKGROUP, not a domain. I can access the shared folder manually when logged in to the client as Administrator. But IIS gets "access denied." Here's what I have done: Set File Sharing = ON Set Password Protected Sharing = OFF Set Public Folder Sharing = ON Shared the folder Added permission to the share: Everyone, Full Control Added permission to the share: NETWORK SERVICE, Full Control Verified that File & Printer Sharing is checked in Windows Firewall Opened port 445 to inbound traffic from local sources I tried adding <remote-machine-name>\NETWORK SERVICE to the share but it says it does not recognize the machine, which makes sense, I guess. As I said, from the other computer I have no trouble accessing the shared folder from my user account, but IIS is shut out. How does the file server even know the difference? I would assume that with Everyone given full control and password protected sharing turned off, it would not matter what the client user account is. In any case, how to solve? UPDATE: To clarify, I am not trying to serve up files on the share directly through IIS. Rather I am writing files to the share from my code (System.IO).

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  • Proper library for enums

    - by Bobson
    I'm trying to refactor some code such that the display is separate from the implementation, and I'm not sure where to put the existing enums. My project is currently structured as follows: Utilities RemoteData (Depends on: Utilities) LocalData (Depends on: RemoteData, Utilities) RemoteWeb (Depends on: RemoteData, Utilities) LocalWeb (Depends on: RemoteData, LocalData, Utilities) I'm now trying to add "ViewLibrary (Depends on: Utilities)" to this list, and then adding it as a new dependency to both RemoteWeb and LocalWeb. It will contain a set of interfaces which the other two projects will implement, use to populate the view, and then consume the result. There's an enum which is currently used in all the projects except Utilities. It thus lives in the RemoteData project, because everything else depends on it. But this new ViewLibrary won't depend on either data project. So how will it know about this enum? Some options I see: Create a new project just for shared enum values. Add it to Utilities, even though it is related to data. Define it a second time in ViewLibrary, and require both RemoteWeb and LocalWeb to convert the one type into the other when they access the shared views. Add a dependency on RemoteData to the ViewLibrary, even though it's supposed to be independent of data-source. Are there any better options? Is this structure flawed to begin with?

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  • Can’t connect to SQL Server 2008 - looks like Shared Memory problem

    - by Proposition Joe
    I am unable to connect to my local instance of SQL Server 2008 Express using SQL Server Management Studio. I believe the problem is related to a change I made to the connection protocols. Before the error occurred, I had Shared Memory enabled and Named Pipes and TCP/IP disabled. I then enabled both Named Pipes and TCP/IP, and this is when I started experiencing the problem. When I try to connect to the server with SSMS (with either my SQL server sysadmin login or with windows authentication), I get the following error message: A connection was successfully established with the server, but then an error occurred during the login process. (provider: Named Pipes Provider, error: 0 - No process is on the other end of the pipe.) (Microsoft SQL Server, Error: 233) Why is it returning a Named Pipes error? Why would it not just use Shared Memory, as this has a higher priority order in the list of connection protocols? It seems like it is not listening on Shared Memory for some reason? When I set Named Pipes to enabled and try to connect, I get the same error message. My windows account is does not have administrator priviliges on my computer - perhaps this is making a difference in some way (as some of the discussions in this post about an "SuperSocketNetLib\Lpc" registry key seems to suggest). I have tried restarting the SQL Server service, by the way, and also tried to get someone to log onto the machine with an admin account to restart the SQL Server service. Still no luck.

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  • Can’t connect to SQL Server 2008 - looks like Shared Memory problem

    - by user38556
    I am unable to connect to my local instance of SQL Server 2008 Express using SQL Server Management Studio. I believe the problem is related to a change I made to the connection protocols. Before the error occurred, I had Shared Memory enabled and Named Pipes and TCP/IP disabled. I then enabled both Named Pipes and TCP/IP, and this is when I started experiencing the problem. When I try to connect to the server with SSMS (with either my SQL server sysadmin login or with windows authentication), I get the following error message: A connection was successfully established with the server, but then an error occurred during the login process. (provider: Named Pipes Provider, error: 0 - No process is on the other end of the pipe.) (Microsoft SQL Server, Error: 233) Why is it returning a Named Pipes error? Why would it not just use Shared Memory, as this has a higher priority order in the list of connection protocols? It seems like it is not listening on Shared Memory for some reason? When I set Named Pipes to enabled and try to connect, I get the same error message. My windows account is does not have administrator priviliges on my computer - perhaps this is making a difference in some way (as some of the discussions in this post about an "SuperSocketNetLib\Lpc" registry key seems to suggest). I have tried restarting the SQL Server service, by the way, and also tried to get someone to log onto the machine with an admin account to restart the SQL Server service. Still no luck.

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  • Where is meta.local_fields set in django.db.models.base.py ?

    - by BryanWheelock
    I'm getting the error: Exception Value: (1110, "Column 'about' specified twice") As I was reviewing the Django error page, I noticed that the customizations the model User, seem to be appended to the List twice. This seems to be happening here in django/db/model/base.py in base_save(): values = [(f, f.get_db_prep_save(raw and getattr(self, f.attname) or f.pre_save(self, True))) for f in meta.local_fields] this is what Django error page shows values to be: values = [(<django.db.models.fields.CharField object at 0xa78996c>, u'kallie'), (<django.db.models.fields.CharField object at 0xa7899cc>, ''), (<django.db.models.fields.CharField object at 0xa789a2c>, ''), (<django.db.models.fields.EmailField object at 0xa789a8c>, u'[email protected]'), (<django.db.models.fields.CharField object at 0xa789b2c>, 'sha1$d4a80$0e5xxxxxxxxxxxxxxxxxxxxddadfb07'), (<django.db.models.fields.BooleanField object at 0xa789bcc>, False), (<django.db.models.fields.BooleanField object at 0xa789c6c>, True), (<django.db.models.fields.BooleanField object at 0xa789d2c>, False), (<django.db.models.fields.DateTimeField object at 0xa789dcc>, u'2010-02-03 14:54:35'), (<django.db.models.fields.DateTimeField object at 0xa789e2c>, u'2010-02-03 14:54:35'), # this is where the values from the User model customizations show up (<django.db.models.fields.BooleanField object at 0xa8c69ac>, False), (<django.db.models.fields.CharField object at 0xa8c688c>, None), (<django.db.models.fields.PositiveIntegerField object at 0xa8c69cc>, 1), (<django.db.models.fields.CharField object at 0xa8c69ec>, 'b5ab1603b2308xxxxxxxxxxx75bca1'), (<django.db.models.fields.SmallIntegerField object at 0xa8c6dac>, 0), (<django.db.models.fields.SmallIntegerField object at 0xa8c6e4c>, 0), (<django.db.models.fields.SmallIntegerField object at 0xa8c6e8c>, 0), (<django.db.models.fields.SmallIntegerField object at 0xa8c6ecc>, 10), (<django.db.models.fields.DateTimeField object at 0xa8c6eec>, u'2010-02-03 14:54:35'), (<django.db.models.fields.CharField object at 0xa8c6f2c>, ''), (<django.db.models.fields.URLField object at 0xa8c6f6c>, ''), (<django.db.models.fields.CharField object at 0xa8c6fac>, ''), (<django.db.models.fields.DateField object at 0xa8c6fec>, None), (<django.db.models.fields.TextField object at 0xa8cb04c>, ''), # at this point User model customizations repeats itself (<django.db.models.fields.BooleanField object at 0xa663b0c>, False), (<django.db.models.fields.CharField object at 0xaa1e94c>, None), (<django.db.models.fields.PositiveIntegerField object at 0xaa1e34c>, 1), (<django.db.models.fields.CharField object at 0xaa1e40c>, 'b5ab1603b2308050ebd62f49ca75bca1'), (<django.db.models.fields.SmallIntegerField object at 0xa8c6d8c>, 0), (<django.db.models.fields.SmallIntegerField object at 0xaa2378c>, 0), (<django.db.models.fields.SmallIntegerField object at 0xaa237ac>, 0), (<django.db.models.fields.SmallIntegerField object at 0xaa237ec>, 10), (<django.db.models.fields.DateTimeField object at 0xaa2380c>, u'2010-02-03 14:54:35'), (<django.db.models.fields.CharField object at 0xaa2384c>, ''), (<django.db.models.fields.URLField object at 0xaa2388c>, ''), (<django.db.models.fields.CharField object at 0xaa238cc>, ''), (<django.db.models.fields.DateField object at 0xaa2390c>, None), (<django.db.models.fields.TextField object at 0xaa2394c>, '')] Since this app is in Production, I can't figure out how to use pdb.set_trace() to see what's going on inside of save_base. The customizations to User are: User.add_to_class('email_isvalid', models.BooleanField(default=False)) User.add_to_class('email_key', models.CharField(max_length=16, null=True)) User.add_to_class('reputation', models.PositiveIntegerField(default=1)) User.add_to_class('gravatar', models.CharField(max_length=32)) User.add_to_class('email_feeds', generic.GenericRelation(EmailFeed)) User.add_to_class('favorite_questions', models.ManyToManyField(Question, through=FavoriteQuestion, related_name='favorited_by')) User.add_to_class('badges', models.ManyToManyField(Badge, through=Award, related_name='awarded_to')) User.add_to_class('gold', models.SmallIntegerField(default=0)) User.add_to_class('silver', models.SmallIntegerField(default=0)) User.add_to_class('bronze', models.SmallIntegerField(default=0)) User.add_to_class('questions_per_page', models.SmallIntegerField(choices=QUESTIONS_PER_PAGE_CHOICES, default=10)) User.add_to_class('last_seen', models.DateTimeField(default=datetime.datetime.now)) User.add_to_class('real_name', models.CharField(max_length=100, blank=True)) User.add_to_class('website', models.URLField(max_length=200, blank=True)) User.add_to_class('location', models.CharField(max_length=100, blank=True)) User.add_to_class('date_of_birth', models.DateField(null=True, blank=True)) User.add_to_class('about', models.TextField(blank=True)) Django1.1.1 Python 2.5

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  • C++ volatile required when spinning on boost::shared_ptr operator bool()?

    - by JaredC
    I have two threads referencing the same boost::shared_ptr: boost::shared_ptr<Widget> shared; On thread is spinning, waiting for the other thread to reset the boost::shared_ptr: while(shared) boost::thread::yield(); And at some point the other thread will call: shared.reset(); My question is whether or not I need to declare the shared pointer as volatile to prevent the compiler from optimizing the call to shared.operator bool() out of the loop and never detecting the change? I know that if I were simply looping on a variable, waiting for it to reach 0 I would need volatile, but I'm not sure if boost::shared_ptr is implemented in such a way that it is not necessary here.

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  • Why cant we create Object if constructor is in private section?

    - by Abhi
    Dear all I want to know why cant we create object if the constructor is in private section. I know that if i make a method static i can call that method using <classname> :: <methodname(...)>; But why cant we create object is my doubt... I also know if my method is not static then also i can call function by the following... class A { A(); public: void fun1(); void fun2(); void fun3(); }; int main() { A *obj =(A*)malloc(sizeof(A)); //Here we can't use new A() because constructor is in private //but we can use malloc with it, but it will not call the constructor //and hence it is harmful because object may not be in usable state. obj->fun1(); obj->fun2(); obj->fun3(); } So only doubt is why cant we create object when constructor is in private section? Thanks in advance

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  • How do I add an object to a binary tree based on the value of a member variable?

    - by Max
    How can I get a specific value from an object? I'm trying to get a value of an instance for eg. ListOfPpl newListOfPpl = new ListOfPpl(id, name, age); Object item = newListOfPpl; How can I get a value of name from an Object item?? Even if it is easy or does not interest you can anyone help me?? Edited: I was trying to build a binary tree contains the node of ListOfPpl, and need to sort it in the lexicographic. Here's my code for insertion on the node. Any clue?? public void insert(Object item){ Node current = root; Node follow = null; if(!isEmpty()){ root = new Node(item, null, null); return; }boolean left = false, right = false; while(current != null){ follow = current; left = false; right = false; //I need to compare and sort it if(item.compareTo(current.getFighter()) < 0){ current = current.getLeft(); left = true; }else { current = current.getRight(); right = true; } }if(left) follow.setLeft(new Node(item, null, null)); else follow.setRight(new Node(item, null, null)); }

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  • [javascript] Can I overload an object with a function?

    - by user257493
    Lets say I have an object of functions/values. I'm interested in overloading based on calling behavior. For example, this block of code below demonstrates what I wish to do. var main_thing = { initalized: false, something: "Hallo, welt!", something_else: [123,456,789], load: { sub1 : function() { //Some stuff }, sub2 : function() { //Some stuff }, all : function() { this.load.sub1(); this.load.sub2(); } } init: function () { this.initalized=true; this.something="Hello, world!"; this.something_else = [0,0,0]; this.load(); //I want this to call this.load.all() instead. } } The issue to me is that main_thing.load is assigned to an object, and to call main_thing.load.all() would call the function inside of the object (the () operator). What can I do to set up my code so I could use main_thing.load as an access the object, and main_thing.load() to execute some code? Or at least, similar behavior. Basically, this would be similar to a default constructor in other languages where you don't need to call main_thing.constructor(). If this isn't possible, please explain with a bit of detail.

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  • How to design a scalable notification system?

    - by Trent
    I need to write a notification system manager. Here is my requirements: I need to be able to send a Notification on different platforms, which may be totally different (for exemple, I need to be able to send either an SMS or an E-mail). Sometimes the notification may be the same for all recipients for a given platform, but sometimes it may be a notification per recipients (or several) per platform. Each notification can contain platform specific payload (for exemple an MMS can contains a sound or an image). The system need to be scalable, I need to be able to send a very large amount of notification without crashing either the application or the server. It is a two step process, first a customer may type a message and choose a platform to send to, and the notification(s) should be created to be processed either real-time either later. Then the system needs to send the notification to the platform provider. For now, I end up with some though but I don't know how scalable it will be or if it is a good design. I've though of the following objects (in a pseudo language): a generic Notification object: class Notification { String $message; Payload $payload; Collection<Recipient> $recipients; } The problem with the following objects is what if I've 1.000.000 recipients ? Even if the Recipient object is very small, it'll take too much memory. I could also create one Notification per recipient, but some platform providers requires me to send it in batch, meaning I need to define one Notification with several Recipients. Each created notification could be stored in a persistent storage like a DB or Redis. Would it be a good it to aggregate this later to make sure it is scalable? On the second step, I need to process this notification. But how could I distinguish the notification to the right platform provider? Should I use an object like MMSNotification extending an abstract Notification? or something like Notification.setType('MMS')? To allow to process a lot of notification at the same time, I think a messaging queue system like RabbitMQ may be the right tool. Is it? It would allow me to queue a lot of notification and have several worker to pop notification and process them. But what if I need to batch the recipients as seen above? Then I imagine a NotificationProcessor object for which I could I add NotificationHandler each NotificationHandler would be in charge to connect the platform provider and perform notification. I can also use an EventManager to allow pluggable behavior. Any feedbacks or ideas? Thanks for giving your time. Note: I'm used to work in PHP and it is likely the language of my choice.

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  • Difference between "Data Binding'","Data Hiding","Data Wraping" and "Encapsulation"?

    - by krishna Chandra
    I have been studying the conpects of Object oriented programming. Still I am not able to distinguish between the following concepts of object oriented programming.. a) Data Binding b) Data Hiding c) Data Wrapping d) encapsulation e) Data Abstraction I have gone through a lot of books ,and I also search the difference in google. but still I am not able to make the difference between these? Could anyone please help me ?

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  • First toe in the water with Object Databases : DB4O

    - by REA_ANDREW
    I have been wanting to have a play with Object Databases for a while now, and today I have done just that.  One of the obvious choices I had to make was which one to use.  My criteria for choosing one today was simple, I wanted one which I could literally wack in and start using, which means I wanted one which either had a .NET API or was designed/ported to .NET.  My decision was between two being: db4o MongoDb I went for db4o for the single reason that it looked like I could get it running and integrated the quickest.  I am making a Blogging application and front end as a project with which I can test and learn with these object databases.  Another requirement which I thought I would mention is that I also want to be able to use the said database in a shared hosting environment where I cannot install, run and maintain a server instance of said object database.  I can do exactly this with db4o. I have not tried to do this with MongoDb at time of writing.  There are quite a few in the industry now and you read an interesting post about different ones and how they are used with some of the heavy weights in the industry here : http://blog.marcua.net/post/442594842/notes-from-nosql-live-boston-2010 In the example which I am building I am using StructureMap as my IOC.  To inject the object for db4o I went with a Singleton instance scope as I am using a single file and I need this to be available to any thread on in the process as opposed to using the server implementation where I could open and close client connections with the server handling each one respectively.  Again I want to point out that I have chosen to stick with the non server implementation of db4o as I wanted to use this in a shared hosting environment where I cannot have such servers installed and run.     public static class Bootstrapper    {        public static void ConfigureStructureMap()        {            ObjectFactory.Initialize(x => x.AddRegistry(new MyApplicationRegistry()));        }    }    public class MyApplicationRegistry : Registry    {        public const string DB4O_FILENAME = "blog123";        public string DbPath        {            get            {                return Path.Combine(Path.GetDirectoryName(Assembly.GetAssembly(typeof(IBlogRepository)).Location), DB4O_FILENAME);            }        }        public MyApplicationRegistry()        {            For<IObjectContainer>().Singleton().Use(                () => Db4oEmbedded.OpenFile(Db4oEmbedded.NewConfiguration(), DbPath));            Scan(assemblyScanner =>            {                assemblyScanner.TheCallingAssembly();                assemblyScanner.WithDefaultConventions();            });        }    } So my code above is the structure map plumbing which I use for the application.  I am doing this simply as a quick scratch pad to play around with different things so I am simply segregating logical layers with folder structure as opposed to different assemblies.  It will be easy if I want to do this with any segment but for the purposes of example I have literally just wacked everything in the one assembly.  You can see an example file structure I have on the right.  I am planning on testing out a few implementations of the object databases out there so I can program to an interface of IBlogRepository One of the things which I was unsure about was how it performed under a multi threaded environment which it will undoubtedly be used 9 times out of 10, and for the reason that I am using the db context as a singleton, I assumed that the library was of course thread safe but I did not know as I have not read any where in the documentation, again this is probably me not reading things correctly.  In short though I threw together a simple test where I simply iterate to a limit each time kicking a common task off with a thread from a thread pool.  This task simply created and added an random Post and added it to the storage. The execution of the threads I put inside the Setup of the Test and then simply ensure the number of posts committed to the database is equal to the number of iterations I made; here is the code I used to do the multi thread jobs: [TestInitialize] public void Setup() { var sw = new System.Diagnostics.Stopwatch(); sw.Start(); var resetEvent = new ManualResetEvent(false); ThreadPool.SetMaxThreads(20, 20); for (var i = 0; i < MAX_ITERATIONS; i++) { ThreadPool.QueueUserWorkItem(delegate(object state) { var eventToReset = (ManualResetEvent)state; var post = new Post { Author = MockUser, Content = "Mock Content", Title = "Title" }; Repository.Put(post); var counter = Interlocked.Decrement(ref _threadCounter); if (counter == 0) eventToReset.Set(); }, resetEvent); } WaitHandle.WaitAll(new[] { resetEvent }); sw.Stop(); Console.WriteLine("{0:00}.{1:00} seconds", sw.Elapsed.Seconds, sw.Elapsed.Milliseconds); }   I was not doing this to test out the speed performance of db4o but while I was doing this I could not help but put in a StopWatch and see out of sheer interest how fast it would take to insert a number of Posts.  I tested it out in this case with 10000 inserts of a small, simple POCO and it resulted in an average of:  899.36 object inserts / second.  Again this is just  simple crude test which came out of my curiosity at how it performed under many threads when using the non server implementation of db4o. The spec summary of the computer I used is as follows: With regards to the actual Repository implementation itself, it really is quite straight forward and I have to say I am very surprised at how easy it was to integrate and get up and running.  One thing I have noticed in the exposure I have had so far is that the Query returns IList<T> as opposed to IQueryable<T> but again I have not looked into this in depth and this could be there already and if not they have provided everything one needs to make there own repository.  An example of a couple of methods from by db4o implementation of the BlogRepository is below: public class BlogRepository : IBlogRepository { private readonly IObjectContainer _db; public BlogRepository(IObjectContainer db) { _db = db; } public void Put(DomainObject obj) { _db.Store(obj); } public void Delete(DomainObject obj) { _db.Delete(obj); } public Post GetByKey(object key) { return _db.Query<Post>(post => post.Key == key).FirstOrDefault(); } … Anyways I hope to get a few more implementations going of the object databases and literally just get familiarized with them and the concept of no sql databases. Cheers for now, Andrew

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