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  • Good programming style when handling multiple objects

    - by Glitch
    I've been programming a software version of a board game. Thus far I have written the classes which will correspond to physical objects on the game board. I'm well into writing the program logic, however I've found that many of the logic classes require access to the same objects. At first I was passing the appropriate objects to methods as they were called, but this was getting very tedious, particularly when the methods required many objects to perform their tasks. To solve this, I created a class which initialises and stores all the objects I need. This allows me to access an object from any class by calling Assets.dice(), for example. But now that I've thought about it, this doesn't seem right. This is why I'm here, I fear that I've created some sort of god class. Is this fear unfounded, or have I created a recipe for disaster?

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  • Question about member function pointers in a heirarchy

    - by Jesse Beder
    I'm using a library that defines an interface: template<class desttype> void connect(desttype* pclass, void (desttype::*pmemfun)()); and I have a small heirarchy class base { void foo(); }; class derived: public base { ... }; In a member function of derived, I want to call connect(this, &derived::foo); but it seems that &derived::foo is actually a member function pointer of base; gcc spits out error: no matching function for call to ‘connect(derived* const&, void (base::* const&)())’ I can get around this by explicitly casting this to base *; but why can't the compiler match the call with desttype = base (since derived * can be implicitly cast to base *)? Also, why is &derived::foo not a member function pointer of derived?

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  • What's the reason both Image and Bitmap classes don't implement a custom equality/hashcode logic?

    - by devoured elysium
    From MSDN documentation, it seems as both GetHashCode() and Equals() haven't been overriden in Bitmap. Neither have them been overriden in Image. So both classes are using the Object's version of them just compares references. I wasn't too convinced so I decided to fire up Reflector to check it out. It seems MSDN is correct in that matter. So, is there any special reason why MS guys wouldn't implement "comparison logic", at least for the Bitmap class? I find it is kinda acceptable for Image, as it is an abstract class, but not so much for the Bitmap class. I can see in a lot of situations calculating the hash code can be an expensive operation, but it'd be alright if it used some kind of lazy evaluation (storing the computed hash code integer in a variable a variable, so it wouldn't have to calculate it later again). When wanting to compare 2 bitmaps, will I have to resort to having to run all over the picture comparing each one of its pixels? Thanks

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  • how can I implement Comparable more than once?

    - by codeman73
    I'm upgrading some code to Java 5 and am clearly not understanding something with Generics. I have other classes which implement Comparable once, which I've been able to implement. But now I've got a class which, due to inheritance, ends up trying to implement Comparable for 2 types. Here's my situation: I've got the following classes/interfaces: interface Foo extends Comparable<Foo> interface Bar extends Comparable<Bar> abstract class BarDescription implements Bar class FooBar extends BarDescription implements Foo With this, I get the error 'interface Comparable cannot be implemented more than once with different arguments...' Why can't I have a compareTo(Foo foo) implemented in FooBar, and also a compareTo(Bar) implemented in BarDescription? Isn't this simply method overloading?

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  • Issue in exec method

    - by mukul sharma
    Hi all, I am a having two python files file1.py and file2.py. I am using exec() to get the method/Variables defined in the file2.py. file1.py have a class as given below class one: def init(self): self.HOOK = None exec(file2.py) self.HOOK = Generate ### call the hook method #### self.HOOK() file2.py looks like as (There is no class define in file2.py) def Generate() do 1 do 2 Hello() def hello() print "hello" Now the problem is as When i run script it is giving a error global name Hello not found. If i remove Hello() from Generate method in file2.py then its work fine. I cant use import file2.py in file1.py,because in file2.py the only one method name (Generate) is fix (its taken as requirement). So apart from Genarate method user can define any method and can call this in generate method, because this approach is not working so i have to write whole code into generate method only and code is also repetitive. Any help is really appreciable...

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  • design a large scale network for an organization

    - by Essam
    hello.i am so new to networking i want to design a large scale network for an organization with HQ and two branches. i want to use class A address for that.my questions are: if i am using the network address 30.0.0.0 for the whole organization how can it be different from another organization company or whatever which is using the same address in another country? now i have the three locations for this organization,so i need 5 subnets [one for the HQ,two for branch A and branch B , one for connecting A to HQ and one for connecting branch B with HQ since i will use central DHCP server at the HQ,is that(number of subnetting) right? is it advisable to use class A or class B for this organization it term of address that will be wasted (lets say it is a university with two branches in two different states)?! that is all your help is highly appropriated.

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  • MVC3 Razor DropDownListFor Enums

    - by jordan.baucke
    Trying to get my project updated to MVC3, something I just can't find: I have a simple datatype of ENUMS: public enum States() { AL,AK,AZ,...WY } Which I want to use as a DropDown/SelectList in my view of a model that contains this datatype: public class FormModel() { public States State {get; set;} } Pretty straight forward: when I go to use the auto-generate view for this partial class, it ignores this type. I need a simple select list that sets the value of the enum as the selected item when I hit submit and process via my AJAX - JSON POST Method. And than the view (???!): <div class="editor-field"> @Html.DropDownListFor(model => model.State, model => model.States) </div> thanks in advance for the advice!

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  • Custom Classes Passed from Service to a UI threads via AIDL

    - by Honza Pokorny
    I have a service that regularly queries a web server for new messages. The service stores the new messages in an arrayList. These messages are implemented using a custom class, storing all kinds of metadata (strings and longs). An activity then connects to this service to retrieve those messages and display them to the user. I have an .aidl file that describes the interface that the service exposes. package com.example.package; interface MyInterface { List<Message> getMessages(); } The Message class extends the Parcelable class which should allow for the IPC transfer. The problem is this: Eclipse gives me an error saying that the type of List<Message> is unknown. Any imports are marked as invalid. Ideas? Thanks

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  • How do I improve the efficiency of the queries executed by this generic Linq-to-SQL data access clas

    - by Lee D
    Hi all, I have a class which provides generic access to LINQ to SQL entities, for example: class LinqProvider<T> //where T is a L2S entity class { DataContext context; public virtual IEnumerable<T> GetAll() { return context.GetTable<T>(); } public virtual T Single(Func<T, bool> condition) { return context.GetTable<T>().SingleOrDefault(condition); } } From the front end, both of these methods appear to work as you would expect. However, when I run a trace in SQL profiler, the Single method is executing what amounts to a SELECT * FROM [Table], and then returning the single entity that meets the given condition. Obviously this is inefficient, and is being caused by GetTable() returning all rows. My question is, how do I get the query executed by the Single() method to take the form SELECT * FROM [Table] WHERE [condition], rather than selecting all rows then filtering out all but one? Is it possible in this context? Any help appreciated, Lee

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  • running a program in Unix vs in Windows

    - by Hristo
    I'm compiling a simple program written in C and I'm using Eclipse as an IDE, both in Windows 7 and on my MacBook Pro. Very simple program my friend wrote and asked me to help him with: int a = 0; char b[2]; printf("Input first class info:\n"); printf("Credit Hours: \n"); scanf("%d", &a); printf("Letter Grade: "); scanf("%s", b); So when I run this on my mac, each line prints and when I encounter the scanf(), I can input and continue as expected. In Windows, I have to input everything and then it will print all the lines. I'm not sure why this is happening... what is the difference b/w Windows and Mac here? Mac: Input first class info: Credit Hours: 4 Letter Grade: B+ Windows: 4 B+ Input first class info: Credit Hours: Letter Grade: Thanks, Hristo

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  • Container of shared_ptr's but iterate with raw pointers

    - by Sean Lynch
    I have a class that holds a list containing boost::shared_ptrs to objects of another class. The class member functions that give access to the elemets in the list return raw pointers. For consistency I'd also like to be able to iterate with raw pointers instead of shared_ptrs. So when I dereference the list iterator, I'd like to get raw pointer, not a shared_ptr. I assume I need to write a custom iterator for this. Is this correct? If so can someone point me in the right direction - I've never done this before.

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  • Container fix width. Center div dynamic width. want left right divs to fill out remaining width equally

    - by james
    Have Three columns..Combine width of all three is fixed.. 2nd ( center ) column will have dynamic content.. I need left and right column to fill out remaining space ( container width - center column dynamic width )equally. Example: http://jsfiddle.net/htKje/ <div class="container"> <div class="bg"></div> <div>Lorem Ipsum</div> <div class="bg"></div> </div> CSS : .container { width:500px; } .bg {backgrould:#CCC; }

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  • Grails searchable plugin

    - by Don
    Hi, In my Grails app, I'm using the Searchable plugin for searching/indexing. I want to write a Compass/Lucene query that involves multiple domain classes. Within that query when I want to refer to the id of a class, I can't simply use 'id' because all classes have an 'id' property. Currently, I work around this problem by adding the following property to a class Foo public Long getFooId() { return id } static transients = ['fooId'] Then when I want to refer to the id of Foo within a query I use 'fooId'. Is there a way I can provide an alias for a property in the searchable mapping rather than adding a property to the class?

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  • Customer session is different in different parts of a Magento website

    - by Josh Pennington
    I have a function inside of a Helper in Magento that returns whether or not a customer attribute equals one. Here is my Helper class class Nie_Nie_Helper_Data extends Mage_Core_Helper_Abstract { public function isNieAdmin() { if(Mage::getSingleton('customer/session')->getCustomer()->getNieAdmin() == 1) { return true; } else { return false; } } } Now when I call this function from a class that extends Mage_Core_Block_Template, everything seems to work fine. However when I try to use this inside one of my controllers, it does not work. In fact when I do Mage::getSingleton('customer/session')-getCustomer()-debug() the only variable that is returned is the website_id. Does anyone know what I have to do in order to get this to work? Thanks Josh Pennington

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  • ASP.NET MVC UpdateModel - fields vs properties??

    - by mrjoltcola
    I refactored some common properties into a base class and immediately my model updates started failing. UpdateModel() and TryUpdateModel() did not seem to update inherited public properties. I cannot find detailed info on MSDN nor Google as to the rules or semantics of these methods. The docs are terse (http://msdn.microsoft.com/en-us/library/dd470933.aspx), simply stating: Updates the specified model instance using values from the controller's current value provider. SOLVED: MVC.NET does indeed handle inherited properties just fine. This turned out to have nothing to do with inheritance. My base class was implemented with public fields, not properties. Switching them to formal properties (adding {get; set; }) was all I needed. This has bitten me before, I keep wanting to use simple, public fields. I would argue that fields and properties are syntactically identical, and could be argued to be semantically equivalent, for the user of the class.

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  • Using Interfaces in JNI

    - by lhw
    I am trying to use (*env)->RegisterNatives to add methods to a defined class which I then add to a callback list. The callback sender of course expects my class to implement a certain interface which I do not. And is failing on execution. If I add the keyword "implements Listener" to my class in Java the javac expects to have the methods definition in Java or with native keyword which I try to avoid here, as I'd like to register the methods within the JNI_OnLoad and execute one of them afterwards. The question now is: Can I implement the interface in JNI or avoid the error message in Java?

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  • Why is the base() constructor not necessary?

    - by Earlz
    Hello, I have a class structure like abstract class Animal { public Animal(){ //init stuff.. } } class Cat : Animal { public Cat(bool is_keyboard) : base() //NOTE here { //other init stuff } } Now then, look at the noted line. If you remove : base() then it will compile without an error. Why is this? Is there a way to disable this behavior? I have had multiple bugs now from forgetting the base() which I would have thought to be required on such a special thing as a constructor.

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  • Generic type in generic collection

    - by Brian Triplett
    I have generic type that looks like: public class GenericClass<T, U> where T : IComparable<T> { // Class definition here } I then have a collection of these instances. What is the cleanest way to pass through the type constraints? public class GenericCollection<V> where V : GenericClass<T, U> // This won't compile { private GenericClass<T, U>[] entries; public V this[index] { get{ return this.entries[index]; } } } Is there perhaps a better way to design this? I think that specifying GenericCollection<T, U, V> where V : GenericClass<T, U> seems awkward. Might be my only option though....

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  • XML Deserialization

    - by Nave
    I have the following xml file. <a> <b> <c>val1</c> <d>val2</d> </b> <b> <c>val3</c> <d>val4</d> </b> <a> I want to deserialize this into a class and I want to access them with the objects of the class created. I am using C#. I am able to deserialize and get the value into the object of class ‘a’ (the <a> tag). but how to access the value of <b> from this object?

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  • How are binding specified for Interface Builder plugins?

    - by Benedict Cohen
    I'm creating an Interface Builder plugin for an NSView subclass. I've been following the Interface Builder Plug-in Programming Guide but it's not answer all my questions. My class has one NSString property and 4 NSColor properties which I want to create bindings for at design time. I can't figure out where the bindings are specified in the plugin project. The documentation states that the Inspector Object is only for creating the Attribute Inspector. The class description file (.classdescription) lists outlets and actions but not bindings. Where do I specify the bindings for my class?

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  • Assign fixed IP address via DHCP by DNS lookup

    - by Janoszen
    Preface I'm building a virtualization environment with Ubuntu 14.04 and LXC. I don't want to write my own template since the upgrade from 12.04 to 14.04 has shown that backwards compatibility is not guaranteed. Therefore I'm deploying my virtual machines via lxc-create, using the default Ubuntu template. The DNS for the servers is provided by Amazon Route 53, so no local DNS server is needed. I also use Puppet to configure my servers, so I want to keep the manual effort on the deployment minimal. Now, the default Ubuntu template assigns IP addresses via DHCP. Therefore, I need a local DHCP server to assign IP addresses to the nodes, so I can SSH into them and get Puppet running. Since Puppet requires a proper DNS setup, assigning temporary IP addresses is not an option, the client needs to get the right hostname and IP address from the start. Question What DHCP server do I use and how do I get it to assign the IP address based only on the host-name DHCP option by performing a DNS lookup on that very host name? What I've tried I tried to make it work using the ISC DHCP server, however, the manual clearly states: Please be aware that only the dhcp-client-identifier option and the hardware address can be used to match a host declaration, or the host-identifier option parameter for DHCPv6 servers. For example, it is not possible to match a host declaration to a host-name option. This is because the host-name option cannot be guaranteed to be unique for any given client, whereas both the hardware address and dhcp-client-identifier option are at least theoretically guaranteed to be unique to a given client. I also tried to create a class that matches the hostname like this: class "my-client-name" { match if option host-name = "my-client-name"; fixed-address my-client-name.my-domain.com; } Unfortunately the fixed-address option is not allowed in class statements. I can replace it with a 1-size pool, which works as expected: subnet 10.103.0.0 netmask 255.255.0.0 { option routers 10.103.1.1; class "my-client-name" { match if option host-name = "my-client-name"; } pool { allow members of "my-client-name"; range 10.103.1.2 10.103.1.2; } } However, this would require me to administer the IP addresses in two places (Amazon Route53 and the DHCP server), which I would prefer not to do. About security Since this is only used in the bootstrapping phase on an internal network and is then replaced by a static network configuration by Puppet, this shouldn't be an issue from a security standpoint. I am, however, aware that the virtual machine bootstraps with "ubuntu:ubuntu" credentials, which I intend to fix once this is running.

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  • Why can't I reclaim my dynamically allocated memory using the "delete" keyword?

    - by synaptik
    I have the following class: class Patient { public: Patient(int x); ~Patient(); private: int* RP; }; Patient::Patient(int x) { RP = new int [x]; } Patient::~Patient() { delete [] RP; } I create an instance of this class on the stack as follows: void f() { Patient p(10); } Now, when f() returns, I get a "double free or corruption" error, which signals to me that something is attempted to be deleted more than once. But I don't understand why that would be so. The space for the array is created on the heap, and just because the function from inside which the space was allocated returns, I wouldn't expect the space to be reclaimed. I thought that if I allocate space on the heap (using the new keyword), then the only way to reclaim that space is to use the delete keyword. Help! :)

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  • Type casting in TPC inheritance

    - by Mohsen Esmailpour
    I have several products like HotelProduct, FlightProduct ... which derived from BaseProduct class. The table of these products will be generated in TPC manner in database. There is OrderLine class which has a BaseProduct. My problem is when i select an OrderLine with related product i don't know how cast BaseProduct to derived product. for example i have this query: var order = (from odr in _context.Orders join orderLine in _context.OrderLines on odr.Id equals orderLine.OrderId join hotel in _context.Products.OfType<HotelProduct>() on orderLine.ProductId equals hotel.Id where odr.UserId == userId && odr.Id == orderId orderby odr.OrderDate descending select odr).SingleOrDefault(); In OrderLine i have BaseProduct properties not properties of HotelProduct. Is there any way to cast BaseProduct to derived class in OrderLine or any other solutions ?

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  • How to query a date in HQL (Hibernate) with Joda Time?

    - by fabien7474
    I am sure that someone familiar with HQL (I am myself a newbie) can easily answer this question. In my Grails application, I have the following domain class. class Book { org.joda.time.DateTime releaseDate //I use the PersistentDateTime for persisting via Hibernate (that use a DATETIME type for MySQL DB) } In my HQL query, I want to retrieve books whose release date is included in range date1..date2 For instance I tried: DateTime date1, date2 ... def queryStr = "select * from Book as b where b.releaseDate > $date1 and b.releaseDate < $date2" def res = Book.executeQuery(queryStr) But I got the exception ...caused by: org.springframework.orm.hibernate3.HibernateQueryException: unexpected token: The error token points to date format (for instance 2009-11-27T21:57:18.010+01:00 or Fri Nov 27 22:01:20 CET 2009) I have also tried to convert date1 into a Date class without success So what is the correct HQL code ? Should I convert to a specific format (which one?) using the patternForStyle method or is there another -cleaner- way to do it? Thanks, Fabien.

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  • Types in Python - Google Appengine

    - by Chris M
    Getting a bit peeved now; I have a model and a class thats just storing a get request in the database; basic tracking. class SearchRec(db.Model): WebSite = db.StringProperty()#required=True WebPage = db.StringProperty() CountryNM = db.StringProperty() PrefMailing = db.BooleanProperty() DateStamp = db.DateTimeProperty(auto_now_add=True) IP = db.StringProperty() class AddSearch(webapp.RequestHandler): def get(self): searchRec = SearchRec() searchRec.WebSite = self.request.get('WEBSITE') searchRec.WebPage = self.request.get('WEBPAGE') searchRec.CountryNM = self.request.get('COUNTRY') searchRec.PrefMailing = bool(self.request.get('MAIL')) searchRec.IP = self.request.get('IP') Bool has my biscuit; I thought that setting bool(self.reque....) would set the type of the string but no matter what I pass it it still stores it as TRUE in the database. I had the same issue with using required=True on strings for the model; the damn thing kept saying that nothing was being passed... but it had. Ta

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