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• advantages of Zend_Db_Table vs raw (My)SQL?

  - by sunwukung

  Currently working on a new Zend application and developing the Model. Having worked with Zend_Db_Table before, I opted to replace references in the Model to the Table API with a custom SQL script to take care of data access duties. Now I'm looking at developing a new application/domain model, and I wanted to get some feedback from people re: their experiences with Zend_Db API vs raw SQL, and use cases where it would be preferable to use the API. From a project perspective, the DB platform is unlikely to change from MySQL - so it doesn't need to be particularly abstract - and I assume writing a custom SQL API will be more performant than the assorted classes the Zend DB API requires.

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• jaxb unmarshal problem

  - by Hoax

  private JAXBContext jaxbContext; private Marshaller marshaller; private Unmarshaller unmarshaller; private PoiList db; public XMLHandler() { try { JAXBContext.newInstance("x.y.shared"); } catch (JAXBException e) { e.printStackTrace(); } } public PoiList readXML() { try { unmarshaller = jaxbContext.createUnmarshaller(); unmarshaller.setEventHandler(new XMLValidEventHandler()); db = (PoiList) unmarshaller.unmarshal(new File("src/source.xml")); } catch (JAXBException e) { e.printStackTrace(); } return db; } gets me this Exception in thread "main" java.lang.NullPointerException at com.sem.server.XMLHandler.readXML(XMLHandler.java:32) at sem.server.testDataAPI.main(testDataAPI.java:13) Line 32 in this case is the jaxbContext.createUnmarshaller() Line. packages are x.y.client x.y.server (includes the XMLHandler) x.y.shared (includes jaxb generated classes) not really sure what the problem is. any help is appreciated!

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• Protocol buffer deserialization and a dynamically loaded DLL in Compact Framework

  - by cloudraven

  I saw a question related to this on the full framework here. Since it seems to have stayed unresolved for quite a while and this is for the compact framework, I though it would be better to create a new question for it. I want to deserialize types for which I am loading assemblies dynamically (with Assembly.LoadFrom) and I am getting a "Unable to identify known-type for ProtoIncludeAttribute" error. In the related question I mentioned, it was hinted that hooking AppDomain.AssemblyResolve event would help solving the problem. It makes sense for the full framework, but that event is not available in the CF. I wonder if there is a way to do this with CF. The structures I am using look a lot like this and all the classes required for deserialization are loaded from the same Assembly. If the assembly is referenced instead of dynamically loaded it works fine, but fails if done dynamically.

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• Django show manytomanyfield on form when definition is on other model

  - by John

  Hi I have the definition for my manytomany relationship on one model but want to display the field on a form for the other model. How do I do this? for example: # classes class modelA(models.Model): name = models.CharField(max_length=300) manytomany = models.ManyToManyField(modelA) class modelB(models.Model): name = models.CharField(max_length=300) # forms class modelBForm(forms.ModelForm): class Meta: model = modelB I want to use the form modelBForm but show a select box with a list from modelA (just how it would work if the model was set to modelA in the form class). How can I do this? Thanks

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• How does a custom accessor method implementation in Core Data look like?

  - by dontWatchMyProfile

  The documentation is pretty confusing on this one: The implementation of accessor methods you write for subclasses of NSManagedObject is typically different from those you write for other classes. If you do not provide custom instance variables, you retrieve property values from and save values into the internal store using primitive accessor methods. You must ensure that you invoke the relevant access and change notification methods (willAccessValueForKey:, didAccessValueForKey:, willChangeValueForKey:, didChangeValueForKey:, willChangeValueForKey:withSetMutation:usingObjects:, and didChangeValueForKey:withSetMutation:usingObjects:). NSManagedObject disables automatic key-value observing (KVO, see Key-Value Observing Programming Guide) change notifications, and the primitive accessor methods do not invoke the access and change notification methods. In accessor methods for properties that are not defined in the entity model, you can either enable automatic change notifications or invoke the appropriate change notification methods. Are there any examples that show how these look like?

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• @SequenceGenerator - allocationSize, reverse engineering with Eclipse Hibernate Tools

  - by Spooky

  I use the Eclipse Hibernate Tools to create domain classes with JPA annotations from my Oracle database. To control sequence generation I have added the following entry to the hibernate.reveng.xml: ... <primary-key> <generator class="sequence"> <param name="sequence">SEQ_FOO_ID</param> </generator> </primary-key> ... This results in the following annotation: @SequenceGenerator(name = "generator", sequenceName = "SEQ_FOO_ID") However I need to set the "allocationSize" like this: @SequenceGenerator(name = "generator", sequenceName = "SEQ_FOO_ID", allocationSize = 1) Is it possible to set this somehow in the hibernate.reveng.xml?

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• What to read as a good intro and quickstart to aspect-oriented programming and metaprogramming?

  - by Ivan

  As I've found myself repeating myself a lot, writing very similar queries and classes for different entities (despite of doing strong object and relational normalisation), etc, I've came to an Idea that I could and should automate the most of this and write an engine which will compile simple declarative models I specify into all the code limiting my job to describe the task and and finally just customise the result as needed. As far as I know this is about metaprogramming and aspect-oriented programming. How do I get acquainted with modern tools available quickly so that I don't invent one more bicycle developing my own?

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• Forcing Flex to update the screen?

  - by ABBarton

  This may be a bit of a beginners question, but I can't for the life of me figure it out. I'm using flex to develop a GUI for a large project, specifically a status bar along the bottom. Within my StatusBar class is a ProgressBar, which other classes doing work can tell to update(change bar completion and label) as they progress. The problem I'm encountering is that flex won't update whats shown on the screen until it's too late, for example ProgressBar initialized, 0% done some class sets the ProgressBar to be 12% done some class does some work some class sets the ProgressBar to be 56% done Whats happening is the 12% done is never displaying, it just hangs at 0% during the work, then skips right to 56% done. I've tried to understand the lifecycle of a flex component (invalidation and validation), and I think I understand it and am applying it correctly, but it's not working at all. I need to tell flex to redraw my StatusBar (or at least the ProgressBar within) after some class sets it to be 12% done, but before some class starts doing its work. How do I do this?

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• creative way for implementing Data object with its corresponding business logic class in java

  - by ekeren

  I have a class that need to be serialized (for both persistentcy and client-server communication) for simplicity's sake let's call the classes Business a BusinessData and I prefix for their Interfaces. All the getter and setter are delegated from Business class to BusinessData class. I thought about implementing IBusinessData interface that will contain all the getter and setters and IBusiness interface that will extend it. I can either make Business extend BuisnessData so I will not need to implement all getter and setter delegates, or make some abstract class ForwardingBusinessData that will only delegate getter and setters. Any of the above option I lose my hierarchy freedom, do any of you have any creative solutions for this problem... I also reviewed DAO pattern: http://java.sun.com/blueprints/patterns/DAO.html

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• Call a function from another Class - Obj C

  - by AndrewDK

  I'm trying to figure out how I can call a function from another one of my classes. I'm using a RootViewController to setup one of my views as lets say AnotherViewController So in my AnotherViewController im going to add in on the .h file @class RootViewController And in the .m file im going to import the View #import "RootViewController.h" I have a function called: -(void)toggleView { //do something } And then in my AnotherViewController I have a button assigned out as: -(void)buttonAction { //} In the buttonAction I would like to be able to call the function toggleView in my RootViewController. Can someone clarify on how I do this. I've tried adding this is my buttonAction: RootViewController * returnRootObject = [[RootViewController alloc] init]; [returnRootObject toggleView]; But I dont think that's right. Thanks in advanced.

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• Make XStream ignore one specific private variable

  - by Tigraine

  Hi guys, I have a little problem with a class I am currently writing a save function for. I'm using XStream (com.thoughtworks.xstream) to serialize a class to XML using the DOMDriver. The class looks like this: public class World { private Configuration config; public World(Configuration config) { this.config = config; } } So, the issue here is that I do not want to serialize Configuration when serializing world, rather I'd like to give XStream a preconstructed Configuration instance when calling fromXml(). Problem here is mainly class design, Configuration holds a private reference to the GUI classes and therefore serializing Configuration means serializing the whole application completely with GUI etc.. And that's kind of bad. Is there a way to instruct XStream to not serialize the private field config, and upon load supply XStream with a configuration instance to use? greetings Daniel

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• advanced python autovivification

  - by Zhang18

  This question is about implementing the full PERL autovivification in python. I know similary questions were asked before and so far the best answre is http://stackoverflow.com/questions/635483/what-is-the-best-way-to-implement-nested-dictionaries-in-python/652284#652284. However, I'm looking to do this: a['x']['y'].append('z') without declaring a['x']['y'] = [] first, or rather, not declaring a['x'] = {} either. I know dict and list classes sorta don't mix so this is hard, but I'm interested in seeing if someone has an ingenius solution probably involving creating an inherited class from dict but defined a new append method on it? I also know this might throw off some python purists who will ask me to stick with Perl. But even just for a challenge, I'd like to see something. thx!

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• what is wrong: "value Parsers is not a member of package scala.util.parsing.combinator"?

  - by Nick Fortescue

  I've got the above odd error message that I don't understand "value Parsers is not a member of package scala.util.parsing.combinator". I'm trying to learn Parser combinators by writing a C parser step by step. I started at token, so I have the classes: import util.parsing.combinator.JavaTokenParsers object CeeParser extends JavaTokenParsers { def token: Parser[CeeExpr] = ident } abstract class CeeExpr case class Token(name: String) extends CeeExpr This is as simple as I could make it. The code below works fine, but if I uncomment the commented line I get the error message given above: object Play { def main(args: Array[String]) { //val parser: _root_.scala.util.parsing.combinator.Parsers.Parser[CeeExpr] CeeParser.token val x = CeeParser.token print(x) } } In case it is a problem with my setup, I'm using scala 2.7.6 via the scala-plugin for intellij. Can anyone shed any light on this? The message is wrong, Parsers is a member of scala.util.parsing.combinator.

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• Using Property Builtin with GAE Datastore's Model

  - by ejel

  I want to make attributes of GAE Model properties. The reason is for cases like to turn the value into uppercase before storing it. For a plain Python class, I would do something like: Foo(db.Model): def get_attr(self): return self.something def set_attr(self, value): self.something = value.upper() if value != None else None attr = property(get_attr, set_attr) However, GAE Datastore have their own concept of Property class, I looked into the documentation and it seems that I could override get_value_for_datastore(model_instance) to achieve my goal. Nevertheless, I don't know what model_instance is and how to extract the corresponding field from it. Is overriding GAE Property classes the right way to provides getter/setter-like functionality? If so, how to do it? Added: One potential issue of overriding get_value_for_datastore that I think of is it might not get called before the object was put into datastore. Hence getting the attribute before storing the object would yield an incorrect value.

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• What is a SQL statement that can tally up the counts even including the Zeros? (all in 1 statement)

  - by Jian Lin

  A SQL statement can give a list of the most popular gifts that are sent in a Social application, all the way to the ones that are sent 1, or 2 times, but it won't include the Zeros. I think the same goes for getting the list of the most popular Classes that students are registering for, when the registration process for all students is 10 days and now it is the 3rd day. Again, we get the count but the Zeros are not there. Is there a simple SQL statement that can show the whole list, including the zeros?

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• how to modify a textbox using remoting

  - by danutz0119

  I am trying to modify a textBox found in the server Form using remoting from the client side. i have tried some solutions i found, but none of them work. the remoting part works propperly, the only thing that I am not able to figure out is this: this is what i have: client side: ... private void btn_b1_Click(object sender, EventArgs e) { ... myFunc.update(string s); ... } ... sharedLibs: public interface myInterf { void update(string s); } server side: here i have 2 classes in the same namespace class class1 : MarshalByRefObject, myInterf { public void update(string s) { //what do i write here to modify textBox1? } } public partial class class2 : Form { ... // here is the textBox i am trying to alter; }

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• Python 2.6, 3 abstract base class misunderstanding

  - by Aaron

  I'm not seeing what I expect when I use ABCMeta and abstractmethod. This works fine in python3: from abc import ABCMeta, abstractmethod class Super(metaclass=ABCMeta): @abstractmethod def method(self): pass a = Super() TypeError: Can't instantiate abstract class Super ... And in 2.6: class Super(): __metaclass__ = ABCMeta @abstractmethod def method(self): pass a = Super() TypeError: Can't instantiate abstract class Super ... They both also work fine (I get the expected exception) if I derive Super from object, in addition to ABCMeta. They both "fail" (no exception raised) if I derive Super from list. I want an abstract base class to be a list but abstract, and concrete in sub classes. Am I doing it wrong, or should I not want this in python?

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• How to customize Json serialization using Scala and Play Framework?

  - by Jonas

  I would like to serialize some Scala case classes to Json. E.g my case class looks like: case class Item ( id: Int, name: String, price: BigDecimal, created: java.util.Date) and I would like to serialize it to Json like this: {"id":3, "name": "apple", "price": 8.00, "created": 123424434} so I need a custom serilization for BigDecimal and for Date. Where I want the data in milliseconds since 1 jan 1970. When using Scala and Play Framework, I can return Json using Json(myObject), but how do I customize the serialization? Or is there any recommended Scala library?

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• Refactoring tools for namespaces and physical project structure

  - by simendsjo

  When I hack around, some code tend to get much bigger than originally planned. As this happens I usually introduce/collapse/merge namespaces, move files between them, move folders etc etc. Sometimes, if I don't have a clear picture of the end result, this is a real pain and really easy to just "skip". This leads the project deteriorate where classes belong elsewhere, strange namespaces, no folders/wrong folders etc. And then I usually cannot take it anymore and do a larger cleanup - which is usually not difficult, just very tedious and it feels nice to do everything at once, so I do a code freeze while finishing up. So my question is... Are there any tools to help refactoring the namespace/physical aspects of a project?

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• Using JSF, JPA and DAO. Without Spring?

  - by ich-bin-drin

  Hi, till now i still worked with JSF and JPA without DAOs. Now i'd like to use DAOs. But how can i initialize the EntityManager in the DAO-Classes? public class AdresseHome { @PersistenceContext private EntityManager entityManager; public void persist(Adresse transientInstance) { log.debug("persisting Adresse instance"); try { entityManager.persist(transientInstance); log.debug("persist successful"); } catch (RuntimeException re) { log.error("persist failed", re); throw re; } } } Have I to use Spring or is there a solution that works without Spring? Thanks.

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• Entity Framework 4 code-only reference column name

  - by Victor

  I created classes: public class Country { public long CountryId {get;set;} public string CountryName {get;set;} } public class Profile { public long ProfileId {get;set;} public string ProfileName {get;set;} public Country Country {get;set;} } and configuration for Profile: public class ProfileConfiguration : EntityConfiguration<Profile> { public IlluminatiCoreProfileConfiguration() { Relation(p => p.Country); } } Then I create context and run context.CreateDatabase(). New database contains table Profiles with column Country_CountryId. How can I write configuration for changing column name to "CountryId"? Thanks.

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• Data Access Layer in ASP.Net: Where do I create the Connection?

  - by atticae

  If I want to create a 3-Layer ASP.Net application (Presentation Layer, Business Layer, Data Access Layer), where is the best place to create the Connection objects? So far I used a helper class in my Presentation Layer to create an IDbCommand from the ConnectionString in the web.config on each page and passed it on to the DAL classes/methods. Now I am not so sure, if this part shouldn't also be included in the DAL somehow, because it obviously is part of the Data Access. The DAL is in a separately compilated project, so I dont have access to the web.config and cannot access the connection string (right?). What is the best practice here?

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• Python: User-Defined Exception That Proves The Rule

  - by bandana

  Python documentations states: Exceptions should typically be derived from the Exception class, either directly or indirectly. the word 'typically' leaves me in an ambiguous state. consider the code: class good(Exception): pass class bad(object): pass Heaven = good() Hell = bad() >>> raise Heaven Traceback (most recent call last): File "<pyshell#163>", line 1, in <module> raise Heaven good >>> raise Hell Traceback (most recent call last): File "<pyshell#171>", line 1, in <module> raise Hell TypeError: exceptions must be classes or instances, not bad so when reading the python docs, should i change 'typically' with ''? what if i have a class hierarchy that has nothing to do with the Exception class, and i want to 'raise' objects belonging to the hierarchy? i can always raise an exception with an argument: raise Exception, Hell This seems slightly awkward to me What's so special about the Exception class, that only its family members can be raised?

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• Java source code generation frameworks

  - by Superfilin

  I have a set of Java 5 source files with old-style Doclet tags, comments and annotations. And based on that I would like to write a generator for another set of Java classes. What is the best way to do that? And are there any good standalone libraries for code analysis/generation in Java? Any shared exprience in this field is appreciated. So, far I have found these: JaxME's Java Source Reflection - seems good, but it does not seem to support annotations. Also it had no release since 2006. Annogen - uses JDK's Doclet generator, which has some bugs under 1.5 JDK. Also it had no releases for a long time. Javaparser - seems good as well and pretty recent, but only supports Visitor pattern for a single class i.e. no query mechanism like in the 2 above packages.

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• Implementing simple business model in Haskell

  - by elmes

  Supose we have a very simple model: Station has at least one Train Train has at least two Stations The model has to allow to check what stations any given train visits and to check what trains visit a particular station. How to model it in Haskell? I am a Haskell newbie, so please correct me: once an object is created, you cannot modify it - you can only make a new object based on that one (~immutability). Am I right? If so, I'll have to create a lot of temporary variables with semi-initialized objects (during deserialization or even in unit tests). Basically what I need is an example of modeling domain classes in Haskell - after reading "Learn you a haskell.." I still have no idea how to use this language.

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