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  • Multiple Inheritence with same Base Classes in Python

    - by Jordan Reiter
    I'm trying to wrap my head around multiple inheritance in python. Suppose I have the following base class: class Structure(object): def build(self, *args): print "I am building a structure!" self.components = args And let's say I have two classes that inherit from it: class House(Structure): def build(self, *args): print "I am building a house!" super(House, self).build(*args) class School(Structure): def build(self, type="Elementary", *args): print "I am building a school!" super(School, self).build(*args) Finally, a create a class that uses multiple inheritance: class SchoolHouse(School, House): def build(self, *args): print "I am building a schoolhouse!" super(School, self).build(*args) Then, I create a SchoolHouse object and run build on it: >>> sh = SchoolHouse() >>> sh.build("roof", "walls") I am building a schoolhouse! I am building a house! I am building a structure! So I'm wondering -- what happened to the School class? Is there any way to get Python to run both somehow? I'm wondering specifically because there are a fair number of Django packages out there that provide custom Managers for models. But there doesn't appear to be a way to combine them without writing one or the other of the Managers as inheriting from the other one. It'd be nice to just import both and use both somehow, but looks like it can't be done? Also I guess it'd just help to be pointed to a good primer on multiple inheritance in Python. I have done some work with Mixins before and really enjoy using them. I guess I just wonder if there is any elegant way to combine functionality from two different classes when they inherit from the same base class.

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  • Inheritance - Could not initialize proxy - no Session.

    - by Ninu
    hello....i'm newbie developer.... i really need help at now... i just get started with Nhibernate thing at .Net... when i learn Inheritance and try it...it makes me confusing...why i get error like this : Initializing[AP.Core.Domain.AccountPayable.APInvoice#API03/04/2010/001]-Could not initialize proxy - no Session. this is my xml : <class xmlns="urn:nhibernate-mapping-2.2" mutable="true" name="AP.Core.Domain.AccountPayable.APAdjustment, AP.Core, Version=1.0.0.0, Culture=neutral, PublicKeyToken=null" table="APAdjustment"> <id name="AdjustmentNumber" type="System.String, mscorlib, Version=2.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089"> <column name="AdjustmentNumber" length="17" /> <generator class="assigned" /> </id> <property name="Amount" type="System.Decimal, mscorlib, Version=2.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089"> <column name="Amount" /> </property> <property name="TransactionDate" type="System.DateTime, mscorlib, Version=2.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089"> <column name="TransactionDate" /> </property> <many-to-one class="AP.Core.Domain.AccountPayable.APInvoice, AP.Core, Version=1.0.0.0, Culture=neutral, PublicKeyToken=null" lazy="proxy" name="PurchaseInvoice"> <column name="PurchaseInvoice_id" not-null="true" /> </many-to-one> <joined-subclass name="AP.Core.Domain.AccountPayable.APCreditAdjustment, AP.Core, Version=1.0.0.0, Culture=neutral, PublicKeyToken=null" lazy="true" table="APCreditAdjustment"> <key> <column name="APAdjustment_id" /> </key> </joined-subclass> </class> </hibernate-mapping> and this is inheritance Class : Parent Class -- public class APAdjustment { #region :FIELD private string adjustmentNumber; private decimal amount; private DateTime transactionDate; private APInvoice purchaseInvoice; Child Class -- public class APCreditAdjustment : APAdjustment { public APCreditAdjustment(){ and this my Data access : public IList<APAdjustment> GetByNameAll() { ICriteria criteria = Nhibernatesession.CreateCriteria(typeof(APAdjustment)); return criteria.List<APAdjustment>() ; } My Problem is : when i load data with gridview ...it works...but i change the property to autogenerate="true" ...i missing "PurchaseInvoice" field...and i change to bind manually,and it works..when i edit that gridview ...i get this error... Initializing[AP.Core.Domain.AccountPayable.APInvoice#API03/04/2010/001]-Could not initialize proxy - no Session so then i change my xml ...lazy="no-proxy" ...it still work...but when edit again ...i get error again ..and i do "Comment out the selected lines" to my association "Many-to-one"...i really works it..but that's not i want... CAN ANYBODY HELP ME...??Plizz...:( Note : I almost forget it ,i use fluent hibernate to generate to database.From fluent Hibernate ..i put *.xml file ...so i'm work to xml NHibernate...not fluent hibernate thing...:)

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  • A question about John Resig's Simple Javascript Inheritance.

    - by Zippo
    I'm using this simple code: http://ejohn.org/blog/simple-javascript-inheritance/ Using this "library", I made this simple class: var Person = Class.extend({ init: function(openningSentence) { this.say(openningSentence); }, say: function(words) { alert(words); } }); The problem with this class, is that I can't call a function using the variable "this" (line 3 in the code gives an error: unknown method "say"). Does anybody knoes if there's a solution for this problem? Btw - I'm using jquery, so if there's a jquery-based solution It'll be great :)

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  • Iterator not accessible because of private inheritance

    - by Bo Tian
    I've created a new class that composes std::deque by private inheritance, i.e, class B : private std::deque<A> { ... }; and in my source code I tried to use iterator of B, i.e., B::iterator it The compiler error is error C2247: 'std::deque<_Ty>::iterator' not accessible because 'B' uses 'private' to inherit from 'std::deque<_Ty>' So the question is, how can I make the iterator accessible?

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  • Simulating inheritance with WF 4.0

    - by pablocastilla
    Hello everyone, I would like to achieve the following: all the workflows created should have the same structure (validation, execution, save results), and all the developers should implement those three stages (maybe leaving it empty). Similar to inheritance with abstract methods. Any ideas?

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  • Question on jpa joined table inheritance

    - by soontobeared
    Hi, The 'DiscriminatorColumn' annotation isn't creating any column in my parent entity. Where am I going wrong ? Here's my code @Entity @Inheritance(strategy=InheritanceType.JOINED) @DiscriminatorColumn(name="TYPE", discriminatorType=DiscriminatorType.STRING,length=20) public class WorkUnit extends BaseEntityClass implements Serializable{ @Entity @DiscriminatorValue(value="G") @Table(name="Group_") @PrimaryKeyJoinColumn public class Group extends WorkUnit implements Serializable{

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  • Windows ACL inheritance issues for FTP server and automated tools

    - by Martin Sall
    I have set up Cerberus FTP server. By default, Cerberus FTP service runs under SYSTEM ACCOUNT. Also I have some console applications which run as scheduled tasks. They are running under a dedicated "Utilities" user account which has "Log on as batch job" permissions. These console applications take uploaded FTP files, process them and then move them to some dedicated archive folder. The problem is that my console apps are throwing Security exceptions when trying to acces the uploaded files. I tried to give the Full control permissions on the ftproot folder for my "Utilities" account and I have checked that "Replace all Child object permissions with inheritable permissions from this object" checkbox, but it affects only current files. When new files are uploaded, they again are not accessible by my "Utilities" account. I tried to go another way and put Cerberus FTP service under "Utilities" account. Then I also needed to give "Utilities" account permissions on Cerberus Data folder in ProgramData. Still no luck - after this operation, Cerberus internal SOAP web service stopped working (although everything else seems to work). I need that SOAP service to be available, so running the Cerberus FTP under "Utilities" account seems to be not an option. Unless I find out, what else do I need to set up for that "Utilities" account to stop Cerberus from complaining. I guess, Cerberus is uploading files to some temporary folder and so those files get the permissions form that folder and keep the same permissions even after moved to the ftproot. What would be the right solution for this which would grant Cerberus FTP server and the "Utilities" account minimal needed permissions to access the contents of the ftproot folder?

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  • Sharepoint 2007 reset permission inheritance

    - by e-mre
    I have this SharePoint 2007 document library which has several levels of folders and files. Some folders in the middle of the hierarchy do not inherit permissions from their parents and have their unique permissions defined. It is a huge library and there are many folders like this. I am currently changing the permission model of my library and I want to reset all those unique permissions and have all of them inherit permissions from the library root. (Something like "Replace child object permissions" checkbox available in windows files system security window) If this is not possible, seeing a list of folders that have their unique permissions defined would also do.

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  • Puppet inheritance of parametrized classes

    - by paweloque
    I have a situation in puppet where I want to inherit from a parametrized class: class base ($basepath) { ... } class extends_base ($ext_param) inherits base { ... } Now trying to instantiate the extends_base class I get the following error message: Must pass basepath to Class[Base] However, I don't see a way how to pass the basepath parameter to the Base class.. I tried to pass the param in the Class[Extends_base] definition, puppet doesn't like this either.

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  • multiple-inheritance substitution

    - by Luigi
    I want to write a module (framework specific), that would wrap and extend Facebook PHP-sdk (https://github.com/facebook/php-sdk/). My problem is - how to organize classes, in a nice way. So getting into details - Facebook PHP-sdk consists of two classes: BaseFacebook - abstract class with all the stuff sdk does Facebook - extends BaseFacebook, and implements parent abstract persistance-related methods with default session usage Now I have some functionality to add: Facebook class substitution, integrated with framework session class shorthand methods, that run api calls, I use mostly (through BaseFacebook::api()), authorization methods, so i don't have to rewrite this logic every time, configuration, sucked up from framework classes, insted of passed as params caching, integrated with framework cache module I know something has gone very wrong, because I have too much inheritance that doesn't look very normal.Wrapping everything in one "complex extension" class also seems too much. I think I should have few working togheter classes - but i get into problems like: if cache class doesn't really extend and override BaseFacebook::api() method - shorthand and authentication classes won't be able to use the caching. Maybe some kind of a pattern would be right in here? How would you organize these classes and their dependencies? EDIT 04.07.2012 Bits of code, related to the topic: This is how the base class of Facebook PHP-sdk: abstract class BaseFacebook { // ... some methods public function api(/* polymorphic */) { // ... method, that makes api calls } public function getUser() { // ... tries to get user id from session } // ... other methods abstract protected function setPersistentData($key, $value); abstract protected function getPersistentData($key, $default = false); // ... few more abstract methods } Normaly Facebook class extends it, and impelements those abstract methods. I replaced it with my substitude - Facebook_Session class: class Facebook_Session extends BaseFacebook { protected function setPersistentData($key, $value) { // ... method body } protected function getPersistentData($key, $default = false) { // ... method body } // ... implementation of other abstract functions from BaseFacebook } Ok, then I extend this more with shorthand methods and configuration variables: class Facebook_Custom extends Facebook_Session { public funtion __construct() { // ... call parent's constructor with parameters from framework config } public function api_batch() { // ... a wrapper for parent's api() method return $this->api('/?batch=' . json_encode($calls), 'POST'); } public function redirect_to_auth_dialog() { // method body } // ... more methods like this, for common queries / authorization } I'm not sure, if this isn't too much for a single class ( authorization / shorthand methods / configuration). Then there comes another extending layer - cache: class Facebook_Cache extends Facebook_Custom { public function api() { $cache_file_identifier = $this->getUser(); if(/* cache_file_identifier is not null and found a valid file with cached query result */) { // return the result } else { try { // call Facebook_Custom::api, cache and return the result } catch(FacebookApiException $e) { // if Access Token is expired force refreshing it parent::redirect_to_auth_dialog(); } } } // .. some other stuff related to caching } Now this pretty much works. New instance of Facebook_Cache gives me all the functionality. Shorthand methods from Facebook_Custom use caching, because Facebook_Cache overwrited api() method. But here is what is bothering me: I think it's too much inheritance. It's all very tight coupled - like look how i had to specify 'Facebook_Custom::api' instead of 'parent:api', to avoid api() method loop on Facebook_Cache class extending. Overall mess and ugliness. So again, this works but I'm just asking about patterns / ways of doing this in a cleaner and smarter way.

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  • Mutable class as a child of an immutable class

    - by deamon
    I want to have immutable Java objects like this (strongly simplyfied): class Immutable { protected String name; public Immutable(String name) { this.name = name; } public String getName() { return name; } } In some cases the object should not only be readable but mutable, so I could add mutability through inheritance: public class Mutable extends Immutable { public Mutable(String name) { super(name); } public void setName(String name) { super.name = name; } } While this is technically fine, I wonder if it conforms with OOP and inheritance that mutable is also of type immutable. I want to avoid the OOP crime to throw UnsupportedOperationException for immutable object, like the Java collections API does. What do you think? Any other ideas?

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  • JPA Cascade delete.

    - by Win Man
    Hi, I am new to JPA/Hibernate. Currently using EJB3, Hibernate/JPA. I have an inheritacnce structure as follows.. @Entity @DiscriminatorColumn(name = "form_type") @Inheritance(strategy = InheritanceType.JOINED) @GenericGenerator(name = "FORMS_SEQ", strategy = "sequence-identity", parameters = @Parameter(name = "sequence", value = "FORMS_SEQ")) @Table(name = "Forms") public abstract class Form{ //code for Form } @Entity @Table(name = "CREDIT_CARDS") @PrimaryKeyJoinColumn(name="CREDIT_CARD_ID") public class CreditCardForm extends Form { //Code for CreditCards. } When I add a row with save the rows are properly inserted into the parent and the child table. However when I try to delete I get an error - 10:19:35,465 ERROR [TxPolicy] javax.ejb.EJBTransactionRolledbackException: Removing a detached instance com.data.entities.form.financial.CreditCard#159? I am using a simple for loop to determine the inheritance type - CreditCard or DebitCard and then calling entityManager.remove(entity). What am I doing wrong? Code for delete.. for(Form content: contents){ if(content.getType()==Type.CREDIT_CARD){ creditCardService.delete((CreditCard)content); } Thanks. WM

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  • How to isolate data per customer, Django powered website

    - by Sawwy
    I have recently started learning python and django and working on a project that includes building a website for collecting information from customers. I am currently trying to figure out best way to isolate the customer data (collected information is sensitive and should only be accessible by customer and the service provider). I found this post Postgresql - one database for everyone, or one-database per customer and my question is that can I automate the model inheritance with customer creation via admin? To be specific, when save() is called for adding customer via django admin, this should create the customer specific tables (create a new set of tables with 'company_name' -prefix). For more information of the environment, I have extended the basic user registration with custom UserProfile adding 'company' and 'role' fields for each user. Upon login, the 'company' of the user will be checked to filter out tables without the 'company_name' prefix. 'Role' will further filter the which company-specific tables and set rights (view, edit). will appreciate any suggestions if more elegant methods could be used to solve the data isolation problem than model inheritance.

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  • Inheritance security rules violated while overriding member - SecurityRuleSet.Level2

    - by Page Brooks
    I have a class that inherits from Exception. In .NET 4, I started receiving a runtime error: Inheritance security rules violated while overriding member: MyBusinessException.GetObjectData(System.Runtime.Serialization.SerializationInfo, System.Runtime.Serialization.StreamingContext)'. Security accessibility of the overriding method must match the security accessibility of the method being overriden. I think the issue is caused by the fact that I am overriding GetObjectData. I know one answer for resolving the issue is to set the SecurityRuleSet: [assembly: SecurityRules(SecurityRuleSet.Level1)] This is not an acceptable answer, I'd like to know how to fix the issue without having to relax the default security rules in .NET 4.

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  • Entity Framework Model with inheritance and RIA Services

    - by TimothyP
    Hi, We have an entity framework model with has some inheritance in it. The following example is not the actuall model, but just to make my point... Let's say Base class: Person Child classes: Employee, Customer The database has been generated, the DomainService has been created and we can get to the data: lstCustomers.ItemsSource = context.Persons; EntityQuery<Person> query = context.GetPeopleQuery().Take(4); context.Load(query); But how can I modify the query to only return Customers ?

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  • CSS-Specifity and CSS Inheritance (concrete question)?

    - by jens
    Hello, i would by thankful for an official link (and section) of the specification for CSS, that explains if: .one two h1 {color:green;font-family:arial;} /*case 1 */ .one two h1 {color:blue;} /*case 2*/ will result in (when evaluated by the browser) .one two h1 {color:blue;font-family:arial;} /*case 3*/ or will it be: .one two h1 {color:blue;} /*case 4*/ ==I have read a lot about inheritance, specifity, cascading etc but I still have not found for the given example which rules apply here. In regard to specifity both elements are equal in specifity the case2 will be the most specify one (as it is equal specific but the last one). But does specifity always apply to the whole selector with ALL properties defined. Or only the the properties that are are in "competition" (and declared in both). thanks!!!!

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  • JSP template inheritance

    - by Ryan
    Coming from a background in Django, I often use "template inheritance", where multiple templates inherit from a common base. Is there an easy way to do this in JSP? If not, is there an alternative to JSP that does this (besides Django on Jython that is :) base template <html> <body> {% block content %} {% endblock %} </body> <html> basic content {% extends "base template" %} {% block content %} <h1>{{ content.title }} <-- Fills in a variable</h1> {{ content.body }} <-- Fills in another variable {% endblock %} Will render as follows (assuming that conten.title is "Insert Title Here", and content.body is "Insert Body Here") <html> <body> <h1>Insert title Here <-- Fills in a variable</h1> Insert Body Here <-- Fills in another variable </body> <html>

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  • Table-per-type inheritance insert problem

    - by gzak
    I followed this article on making a table-per-type inheritance model for my entities, but I get the following error when I try to add an instance of a subclass to the database. Here is how I create the subtype: var cust = db.Users.CreateObject<Customer>(); // Customer inherits User db.Users.AddObject(cust); db.SaveChanges(); I get the following error when I make that last call: "A value shared across entities or associations is generated in more than one location. Check that mapping does not split an EntityKey to multiple store-generated columns." With the following inner exception: "An item with the same key has already been added." Any ideas on what I could be missing?

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  • insert into several inheritance tables with OUTPUT - sql servr 2005

    - by csetzkorn
    Hi, I have a bunch of items – for simplicity reasons – a flat table with unique names seeded via bulk insert: create table #items ( ItemName NVARCHAR(255) ) The database has this structure: create table Statements ( Id INT IDENTITY NOT NULL, Version INT not null, FurtherDetails varchar(max) null, ProposalDateTime DATETIME null, UpdateDateTime DATETIME null, ProposerFk INT null, UpdaterFk INT null, primary key (Id) ) create table Item ( StatementFk INT not null, ItemName NVARCHAR(255) null, primary key (StatementFk) ) Here Item is a child of Statement (inheritance). I would like to insert items in #items using a set based approach (avoiding triggers and loops). Can this be achieved with OUTPUT in my scenario. A ‘loop based’ approach is just too slow where I use something like this: insert into Statements (Version, FurtherDetails, ProposalDateTime, UpdateDateTime, ProposerFk, UpdaterFk) VALUES (1, null, getdate(), getdate(), @user_id, @user_id) etc. This is a start for the OUTPUT based approach – but I am not sure whether this would work in my case as ItemName is only inserted into Item: insert into Statements ( Version, FurtherDetails, ProposalDateTime, UpdateDateTime, ProposerFk, UpdaterFk ) output inserted.Id ... ??? Thanks. Best wishes, Christian

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  • C++ vtable resolving with virtual inheritance

    - by Tomas Cokis
    I was curious about C++ and virtual inheritance - in particular, the way that vtable conflicts are resolved between bass and child classes. I won't pretend to understand the specifics on how they work, but what I've gleamed so far is that their is a small delay caused by using virtual functions due to that resolution. My question then is if the base class is blank - ie, its virtual functions are defined as: virtual void doStuff() = 0; Does this mean that the resolution is not necessary, because there's only one set of functions to pick from? Forgive me if this is an stupid question - as I said, I don't understand how vtables work so I don't really know any better.

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  • Rails table inheritance issue

    - by Tristan O'Neil
    I've setup some models in the table inheritance fashion and everything seems to be all fine and dandy. But, when I use a collection select field to select values from one of the models it saves it but it saves the ID of the data and not the actual value of the data. So when I try to display the value on the show view it just shows the corresponding ID and not the actual value. Here is my setup. I'm using formtastic as a side note. View <%= show_field "County", @company.county %> Form <%= f.input :county, :label => 'County', :as => :select, :collection => County.find(:all) %> Base Model class Tag < ActiveRecord::Base before_create :set_type before_update :set_type attr_accessible :type, :name, :category belongs_to :company def set_type self.type = self.category end end Inherited Model class County < Tag end

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