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• 'Static/Constant' business ojects

  - by UpTheCreek

  I don't quite know how to ask this question, so I'll phase it as an example: Imagine in an application you have a Country object. There are two properties of this object: Name, and a 'Bordering Countries' collection. More properties might be added later, but it will be the kind of information that would change very rarely (e.g. changes of country names/borders) Lets say this application needs to know about all of the countries in the world. Where would you store these object's state? How would you new them up? It seems silly to store all this state in the DB, since it won't change very often. One option might be to have an abstract 'country' base object, and have a class for each country inheriting from this with the details of each country. But this doesn't seem quite right to me. What is the proper way of dealing with these kinds of objects?

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• Is concatenating with an empty string to do a string conversion really that bad?

  - by polygenelubricants

  Let's say I have two char variables, and later on I want to concatenate them into a string. This is how I would do it: char c1, c2; // ... String s = "" + c1 + c2; I've seen people who say that the "" + "trick" is "ugly", etc, and that you should use String.valueOf or Character.toString instead. I prefer this construct because: I prefer using language feature instead of API call if possible In general, isn't the language usually more stable than the API? If language feature only hides API call, then even stronger reason to prefer it! More abstract! Hiding is good! I like that the c1 and c2 are visually on the same level String.valueOf(c1) + c2 suggests something is special about c1 It's shorter. Is there really a good argument why String.valueOf or Character.toString is preferrable to "" +? Trivia: in java.lang.AssertionError, the following line appears 7 times, each with a different type: this("" + detailMessage);

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• how to use multiple $_name using extends Zend_Db_Table_Abstract in zend frame work.

  - by karthik

  we tried to give our tables(users,messages) like this in two different abstract classes but it is not working. This is included in a file childconnect1.php ,is there any relation between the file name(childconnect1.php) and the class(Application_Model_childconnect1). class Application_Model_childconnect1 extends Zend_Db_Table_Abstract { protected $_name = 'users'; public function loginvalidation($username,$pwd) { $row = $this->fetchRow('UserName = \'' . $username . '\'and UserPW = \''. $pwd . '\''); if (!$row) { $msg="invalid"; return $msg; } else { return $row->toArray(); } } } class Application_Model_childconnect2 extends Zend_Db_Table_Abstract { protected $_name = 'messages'; public function replymessage($message) { $data=array( 'MessageText'=>$message ); $this->insert($data); } }

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• Does Qt support virtual pure slots ?

  - by ereOn

  Hi, My GUI project in Qt has a lot of "configuration pages" classes which all inherit directly from QWidget. Recently, I realized that all these classes share 2 commons slots (loadSettings() and saveSettings()). Regarding this, I have two questions: Does it make sense to write a intermediate base abstract class (lets name it BaseConfigurationPage) with these two slots as virtual pure methods ? (Every possible configuration page will always have these two methods, so I would say "yes") Before I do the heavy change in my code (if I have to) : does Qt support virtual pure slots ? Is there anything I should be aware of ? Here is a code example describing everything: class BaseConfigurationPage : public QWidget { // Some constructor and other methods, irrelevant here. public slots: virtual void loadSettings() = 0; virtual void saveSettings() = 0; }; class GeneralConfigurationPage : public BaseConfigurationPage { // Some constructor and other methods, irrelevant here. public slots: void loadSettings(); void saveSettings(); };

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• Inheriting database connection in PHP OOP

  - by vrode

  My abstract class Database is made for database interaction and any child of this class (UserDatabase, ActionDatabase, EventDatabase) inherits its database connection which is defined as static. `abstract class Database { static $connection = mysql_connect( ); } class UserDatabase extends Database { ... public function __construct( ) { $connection ? "connected" : "not connected"; $this-table = "users"; mysql_query( "FROM " . $this-table . " SELECT *" ); } } ` Does that mean, that my database connection is only set up and stored in memory once and passed on to subclasses as reference without being replicated for each instance? Is this how you would implement you OOP-correct database interface?

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• JPA EclipseLink Auditing for Oracle issue with SessionCustomizer...

  - by enrique

  I was trying to use the SessionCustomizer for auditing with v$session.program for oracle and it works with JDBC but i need it working with JPA, so i read a bit more the documentation for SESSION_CUSTOMIZER in this site: http://wiki.eclipse.org/Using_EclipseLink_JPA_Extensions_(ELUG)#EclipseLink_JPA_Persistence_Unit_Properties_for_Customization_and_Validation but had not lucky in making it work in passing the program name parameter to oracle with the v$session.program... i was using the SessionCustomizer and it is an interface so my code is as follows: package com.util; import org.eclipse.persistence.config.SessionCustomizer; import org.eclipse.persistence.sessions.Session; /** * * @author xkalibur */ public class ProgramCustomizer implements SessionCustomizer{ public void customize(Session s) throws Exception { s.getDatasourceLogin().setProperty("v$session.program","Customers"); } } then in CustomerFacade : ProgramCustomizer pc=new ProgramCustomizer(); public void edit(Customer customer) { emProperties.put(PersistenceUnitProperties.SESSION_CUSTOMIZER,pc); em=factory.createEntityManager(emProperties); em.merge(customer); } and returns the following error: javax.ejb.EJBException Caused by: java.lang.NullPointerException at com.facades.CustomerFacade.edit(CustomerFacade.java:48) please some help...

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• What real life bad habits has programming given you? [closed]

  - by Jacob T. Nielsen

  Programming has given me a lot of bad habits and it continues to give me more everyday. But I have also gotten some bad habits from the mindset that I have put myself in. There simply are some things that are deeply rooted in my nature, though some of them I wish I could get rid of. A few: Looking for polymorphism, inheritance and patterns in all of God's creations. Explaining the size of something in pixels and colors in hex code. Using code related abstract terms in everyday conversations. How have you been damaged?

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• how to extract data from excel (apache poi) to put it in mysql table using jsp? [ SOLVED]

  - by Nihad KH

  I want to extract data from excel sheet to insert it into a mysql table using jsp, so far i've done this and its printing data into the outpout(using apache poi),what should i add to this code ? Output : Name Age Adress Mark 35 New york,AA Elise 22 India,bb Charlotte 45 France,cc Readexcel.jsp : <%@page import="java.sql.Statement"%> <%@page import="java.util.ArrayList"%> <%@page import="java.sql.PreparedStatement"%> <%@page import="java.sql.Connection"%> <%@page import="java.util.Date"%> <%@page import="org.apache.poi.ss.usermodel.Cell"%> <%@page import="org.apache.poi.ss.usermodel.Row"%> <%@page import="org.apache.poi.xssf.usermodel.XSSFSheet"%> <%@page import="org.apache.poi.xssf.usermodel.XSSFWorkbook"%> <%@page import="java.io.File"%> <%@page import="org.apache.commons.io.FilenameUtils"%> <%@page import="org.apache.commons.fileupload.FileItem"%> <%@page import="java.util.Iterator"%> <%@page import="java.util.List"%> <%@page import="org.apache.commons.fileupload.servlet.ServletFileUpload"%> <%@page import="org.apache.commons.fileupload.disk.DiskFileItemFactory"%> <%@page import="org.apache.commons.fileupload.FileItemFactory"%> <%@page contentType="text/html" pageEncoding="UTF-8"%> <!DOCTYPE html> <html> <head> <meta http-equiv="Content-Type" content="text/html; charset=UTF-8"> <title>PRINT DATA FROM EXCEL FILE</title> </head> <body> <% try{ boolean ismultipart=ServletFileUpload.isMultipartContent(request); if(!ismultipart){ }else{ FileItemFactory factory = new DiskFileItemFactory(); ServletFileUpload upload = new ServletFileUpload(factory); List items = null; try{ items = upload.parseRequest(request); }catch(Exception e){ } Iterator itr = items.iterator(); while(itr.hasNext()){ FileItem item = (FileItem)itr.next(); if(item.isFormField()){ }else{ String itemname = item.getName(); if((itemname==null || itemname.equals(""))){ continue; } String filename = FilenameUtils.getName(itemname); File f = checkExist(filename); item.write(f); try{ XSSFWorkbook workbook = new XSSFWorkbook(item.getInputStream()); XSSFSheet sheet = workbook.getSheetAt(0); Iterator<Row> rowIterator = sheet.iterator(); while (rowIterator.hasNext()){ Row row = rowIterator.next(); Iterator<Cell> cellIterator = row.cellIterator(); while (cellIterator.hasNext()) { Cell cell = cellIterator.next(); switch (cell.getCellType()){ case Cell.CELL_TYPE_NUMERIC: out.print(cell.getNumericCellValue() + "t"); break; case Cell.CELL_TYPE_STRING: out.print(cell.getStringCellValue() + "t"); break;} } out.println(""); } }catch (Exception e){ e.printStackTrace(); } } } } }catch(Exception e){ } finally { out.close(); } %> <%! private File checkExist(String fileName){ String saveFile = "D:/upload/"; File f = new File(saveFile+"/"+fileName); if(f.exists()){ StringBuffer sb = new StringBuffer(fileName); sb.insert(sb.lastIndexOf("."),"-"+new Date().getTime()); f = new File(saveFile+"/"+sb.toString()); } return f; } %> </body> </html> I've created a table in my database named EXCELDATA with the header of the excel sheet : ExcelData (Name varchar(50),age int,adress varchar(50)); what should i add to this code to get the data from the excel sheet to the mysql table ??

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• Validates presence of each other in two associated models

  - by Sergey Alekseev

  I have the following two models: class Parent < ActiveRecord::Base has_one :child, dependent: :destroy validates :child, presence: true end class Child < ActiveRecord::Base belongs_to :parent validates :parent, presence: true end I want to create Parent object. If I do the following: Parent.create! or Factory(:parent) Exception raises: ActiveRecord::RecordInvalid: Validation failed: Child can't be blank But I can't create Child object without Parent object for the same reason - I need to create Parent object first in order to pass presence validation. As it appears I have some kind of infinite recursion here. How to solve it?

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• designing multi module J2EE application

  - by user728947

  Might be my question is abstract or out of context, but i am asking here since i have little idea how this happens. I am wondering how big application/ platform break down there application in to multiple module and how they able to manage modules dependencies. For example in some E-commerce application they tend to break down it in various modules like pricing,promotions,shipping.import/export and many more. when we develop those application we hardly think about the underlying modules and how they have been designed to provides functionalists. Most of those module are not web-applications but are standalone module and not deployed in the web-app as jar files. can any one help me to understand how they break up things or is there any standard way to do this.any help/resources to get insight will really be helpful

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• Could not able to register the third party DLL using regsvr32

  - by Mahadev Malkar

  i have been trying to register the third party dll file using the regsvr32 command, but it keeps giving me the error that 'the dll doesn't have a entry point, dll could not be registered'. Is it possible to register the dll and use it as a COM component in .NET ? Or I want to use that dll as a COM component in c#.NET. Is there any way to use that dll as COM Component. When i tried to use it as COM component, the dll file, its methods, interfaces are visible in .NET. but when i tried to use any of that interface it gives me error as 'Retrieving the COM class factory for component with CLSID {C4CC4F47-2AF6-41FA-A43D-01E8B3050D3F} failed due to the following error: 80040154.'. Plz tell me any solution.

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• Managing memory of polymorphic timed events with DLL

  - by Milo

  Here is my issue. My Gui library that I made supports timed events. Basically, I have a class called TimedEvent which users inherit from. They then do: addTimedEvent(new DerivedTimedEvent(...)); However given the nature of timed events, I manage the memory afterwards. So when the timed event has done its thing, my library calls delete on it. Although it runs fine, that is because the exe and the library were both built with msvc 2008. I think I might have trouble if I have 2 versions of the runtime, one for the lib, and one for the exe. What can I do to fix this? I can't create a factory because the derived type is on the exe side of things. I also cannot ask the user to call delete since they might not have a way to keep track of time, or know if the event was delayed for whatever reason. Thanks

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• Consequences in PHP of implementing an interface through two different routes?

  - by Daniel Bingham

  What are the consequences of implementing the same interface through two different routes in PHP, are there any? What I mean, is something like this: interface baseInterface {} abstract class baseClass implements baseInterface { } interface myInterface extends baseInterface {} class myClass extends baseClass implements myInterface {} In this case myClass implements baseInterface from two different parents - myInterface and baseClass. Are there any consequences to this? My instinct is that PHP should handle this fine, but I just want to make sure. What exactly does PHP do in this case? Does it just check to see that the necessary functions are implemented for the interface each time it discovers it and call it a day or does it do something more?

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• Trust metrics and related algorithms

  - by Nick Gerakines

  I'm trying to learn more about trust metrics (including related algorithms) and how user voting, ranking and rating systems can be wired to stiffle abuse. I've read abstract articles and papers describing trust metrics but haven't seen any actual implementations. My goal is to create a system that allows users to vote on other users and the content of other users and with those votes and related meta-data, determine if those votes can be applied to a users level or popularity. Have you used or seen some sort of trust system within a social graph? How did it work and what were its areas of strength and weaknesses?

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• Hibernate, select by id or unique column

  - by Nican

  I am using hibernate for Java, and I want to be able to select users by id or by name from the database. Nice thing about Hibernate is that it caches the result by id, but I seem to be unable to make it cache by name. static Session openSession = Factory.openSession(); public static User GetUser(int Id) { return (User) openSession.get(User.class, new Integer(Id)); } public static User GetUser( String Name ){ return (User) openSession.createCriteria( User.class ). add( Restrictions.eq("username", Name) ). uniqueResult(); } If I use GetUser(1) many times, hibernate will only show that it executed the first time. But every time I use GetUser("user1"), hibernate shows that it is executing a new query to database. What would be the best way to have the string identifier be cached also?

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• IRepository with Inherited Classes

  - by Stacey

  In keeping with the Repository pattern of data input, I've a question in regards to using inherited classes. For instance, suppose I would have the class... class Employee IEmployeeRepository { Add(Employee employee); } This works fine, nothing wrong with it so far... but now let's say I continue on.. class Manager : Employee Okay, now let's assume that I never need to enter a manager different than an Employee? What's the best approach here? Would a scenario such as .. IEmployeeRepository { Add<T>(T employee) where T : Employee } Be the best approach, or do I need to abstract a different repository for each type?

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• Fluent NHibernate ExportSchema without connexion string

  - by Vince

  Hi all, I want to propose to user a way to generate database table script creation. To do this for now i use NHibernate ExportSchema bases on a NHibernate configuration generated with Fluent NHibernate this way (during my ISessionFactory creation method): FluentConfiguration configuration = Fluently.Configure(); ... Mapping conf ... configuration.Database(fluentDatabaseProvider); this.nhibernateConfiguration = configuration.BuildConfiguration(); returnSF = configuration.BuildSessionFactory(); ... Later new SchemaExport(this.nhibernateConfiguration) .SetOutputFile(filePath) .Execute(false, false, false); fluentDatabaseProvider is a FluentNHibernate IPersistenceConfigurer which is needed to get proper sql dialect for database creation. When factory is created with an existing database, everything works fine. But what i want to do is to create an NHibernate Configuration object on a selected database engine without a real database behind the scene... And i don't manage to do this. If anybody has some idea.

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• Table per subclass inheritance relationship: How to query against the Parent class without loading a

  - by Arthur Ronald F D Garcia

  Suppose a Table per subclass inheritance relationship which can be described bellow (From wikibooks.org - see here) Notice Parent class is not abstract @Entity @Inheritance(strategy=InheritanceType.JOINED) public class Project { @Id private long id; // Other properties } @Entity @Table(name="LARGEPROJECT") public class LargeProject extends Project { private BigDecimal budget; } @Entity @Table(name="SMALLPROJECT") public class SmallProject extends Project { } I have a scenario where i just need to retrieve the Parent class. Because of performance issues, What should i do to run a HQL query in order to retrieve the Parent class and just the Parent class without loading any subclass ???

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• WCF interoperability with WSDL proxy and performance consideration advise.

  - by user194917

  I'm essentially writing a broker service. The requirement is that I write an API that acts as an intermediary broker between our in-house developed services and a 3rd party provided API. The intention being that my API abstract the actual communication with the 3rd party API from our internal systems. The architect on the project chose WCF as the communication framework. The problem is that 70 percent of our subscriber applications are written in .Net 2 and as such have no access to the class libraries required to implement a WCF proxy. The end result being that our proxy classes are loosely based on the code auto generated by the WSDL tool as opposed to the SvcUtil tool. My question is, although I have no issues implementing the required proxy classes using basicHttp as the actual binding and using the WSDL tool, are there any special considerations that I need to take into account in this scenario? I.E proxy optimizations and the like. Thanks in advance.

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• Interface with generic parameters- can't get it to compile

  - by user997112

  I have an interface like so: public interface MyInterface<E extends Something1> { public void meth1(MyClass1<E> x); } and I have a subclass whose superclass implements the above interface: public class MyClass2<E extends Something1> extends Superclass{ public MyClass2(){ } public void meth1(MyClass1 x) { // TODO Auto-generated method stub } } superclass: public abstract class Superclass<E extends Something1> implements MyInterface{ MyClass1<E> x; protected E y; public Superclass(){ } } the problem is that the parameter for meth1() is supposed to be generic. If I do MyClass1 it doesn't like it and the only way I can get it to compile is by leaving out generic parameters- which feels wrong. What's going wrong?

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• How to make form validation in Django dynamic?

  - by Oli

  I'm trying to make a form that handles the checking of a domain: the form should fail based on a variable that was set earlier in another form. Basically, when a user wants to create a new domain, this form should fail if the entered domain exists. When a user wants to move a domain, this form should fail if the entered domain doesn't exist. I've tried making it dynamic overload the initbut couldn't see a way to get my passed variabele to the clean function. I've read that this dynamic validation can be accomplished using a factory method, but maybe someone can help me on my way with this? Here's a simplified version of the form so far: #OrderFormStep1 presents the user with a choice: create or move domain class OrderFormStep2(forms.Form): domain = forms.CharField() extension = forms.CharField() def clean(self): cleaned_data = self.cleaned_data domain = cleaned_data.get("domain") extension = cleaned_data.get("extension") if domain and extension: code = whoislookup(domain+extension); #Raise error based on result from OrderFormStep1 #raise forms.ValidationError('error, domain already exists') #raise forms.ValidationError('error, domain does not exist') return cleaned_data

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• Why Is It That Generics Constraint Can't Be Casted to Its Derived Type?

  - by Ngu Soon Hui

  It is quite puzzling to find out that Generics Constraint Can't Be Casted to Its Derived Type. Let's say I have the following code: public abstract class BaseClass { public int Version { get { return 1; } } public string FixString { get; set; } public BaseClass() { FixString = "hello"; } public virtual int GetBaseVersion() { return Version; } } public class DeriveClass: BaseClass { public new int Version { get { return 2; } } } And guess what, this method will return a compilation error: public void FreeConversion<T>(T baseClass) { var derivedMe = (DeriveClass)baseClass; } I would have to cast the baseClass to object first before I can cast it to DerivedClass. Seems to me pretty ugly. Why this is so?

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• execute external command / application from java

  - by IttayD

  I'm looking for a package to support reliably executing external processes from Java. My criteria: Abstract over OS. So if I want to run 'foo', it will look for 'foo.bat', 'foo.exe' under windows and 'foo' under other OSs (or, have a way of passing a map of os-command) Being able to execute Java classes by simply giving the class name and arguments (so the package locates the java command, copies jvm flags and then executes) Process stdout and stderr properly Watchdog / Monitoring capabilities I've looked at commons-exec but it looks like it answers only 3 & 4. Ant has support for execution but looks like an overkill to use it for this purpose only.

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• Check if a symlink has changed

  - by BCS

  I have a daemon that, when it's started, loads its data from a directory that happens to be a symlink. Periodically, new data is generated and the symlink updated. I want a bash script that will check if the current symlink is the same as the old one (that the daemon started with) and if not, restart the daemon. My current thought is: if [[ ! -e $old_dir || $(readlink "$data_dir") == $(readlink "$old_dir") ]]; then echo restart ... ln "$(readlink "$data_dir")" "$old_dir" -sf else echo no restart fi The abstract requirement is: each time the script runs, it needs to check if a symlink on a given path now points to a something other than it did the last time and if so do something. (The alternative would be to check if the data at the path has changed but I don't see that being any cleaner.) My questions: Is this a good approach? Does anyone have a better idea? Where should I put $old_dir?

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• Unit Testing: hard dependency MessageBox.Show()

  - by Sean B

  What ways can the SampleConfirmationDialog be unit tested? The SampleConfirmationDialog would be exercised via acceptance tests, however how could we unit test it, seeing as MessageBox is not abstract and no matching interface? public interface IConfirmationDialog { /// <summary> /// Confirms the dialog with the user /// </summary> /// <returns>True if confirmed, false if not, null if cancelled</returns> bool? Confirm(); } /// <summary> /// Implementation of a confirmation dialog /// </summary> public class SampleConfirmationDialog : IConfirmationDialog { /// <summary> /// Confirms the dialog with the user /// </summary> /// <returns>True if confirmed, false if not, null if cancelled</returns> public bool? Confirm() { return MessageBox.Show("do operation x?", "title", MessageBoxButton.YesNo, MessageBoxImage.Question) == MessageBoxResult.Yes; } }

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