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  • How to implement iterator as an attribute of a class in Java

    - by de3
    Hi, let's say I have this simple MyArray class, with two simple methods: add, delete and an iterator. In the main method we can see how it is supposed to be used: public class MyArray { int start; int end; int[] arr; myIterator it; public MyArray(){ this.start=0; this.end=0; this.arr=new int[500]; it=new myIterator(); } public void add(int el){ this.arr[this.end]=el; this.end++; } public void delete(){ this.arr[this.start]=0; this.start++; } public static void main(String[] args){ MyArray m=new MyArray(); m.add(3); m.add(299); m.add(19); m.add(27); while(m.it.hasNext()){ System.out.println(m.it.next()); } } And then MyIterator should be implemented somehow: import java.util.Iterator; public class myIterator implements Iterator{ @Override public boolean hasNext() { // TODO Auto-generated method stub return false; } @Override public Object next() { // TODO Auto-generated method stub return null; } @Override public void remove() { // TODO Auto-generated method stub } } MyIterator should iterate arr from MyArray class, from start to end values; both are also attributes of MyArray. So, as MyIterator should use MyArray attributes, how should MyIterator be implemented? Perhaps I can send the current object in the initialization: it=new myIterator(this); But I guess it's not the best soultion. Or maybe MyArray itself should implement Iterator interface? How is this solved?

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  • Temporarily disable vim plugin without relaunching

    - by simont
    I'm using c-support in Vim. One of it's features is the automatic comment expansion. When I'm pasting code into Vim from an external editor, the comments are expanded (which gives me double-comments and messes up the paste - see below for example). I'd like to be able to disable the plugin, paste, then re-enable it, without relaunching Vim. I'm not sure if this is possible. The SO questions here, here and here all describe methods to disable plugins, but they all require me to close Vim, mess with my .vimrc or similar, and relaunch; if I have to close Vim, I might as well cat file1 >> myfile; vim myfile, then shift the lines internally, which will be just as quick. Is it possible to disable a plugin while running vim without relaunching, preferably in a way which allows me to map a hot-key toggle-plugin (so re-sourcing ~/.vimrc is alright; that's mappable to a hotkey [I imagine, haven't tried it yet])? Messed up comments: /* * * Authors: * * A Name * * * * Copyright: * * A Name, 2012 * */ EDIT: It turns out you can :set paste, :set nopaste (which, to quote :help paste, will "avoid unexpected effects [while pasting]". (See the comments). However, I'm still curious whether you can disable/enable a plugin as per the original question, so I shall leave the question open.

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  • Conditional compilation hackery in C# - is there a way to pull this off?

    - by Chris
    I have an internal API that I would like others to reference in their projects as a compiled DLL. When it's a standalone project that's referenced, I use conditional compilation (#if statements) to switch behavior of a key web service class depending on compilation symbols. The problem is, once an assembly is generated, it appears that it's locked into whatever the compilation symbols were when it was originally compiled - for instance, if this assembly is compiled with DEBUG and is referenced by another project, even if the other project is built as RELEASE, the assembly still acts as if it was in DEBUG as it doesn't need recompilation. That makes sense, just giving some background. Now I'm trying to work around that so I can switch the assembly's behavior by some other means, such as scanning the app/web config file for a switch. The problem is, some of the assembly's code I was switching between are attributes on methods, for example: #if PRODUCTION [SoapDocumentMethodAttribute("https://prodServer/Service_Test", RequestNamespace = "https://prodServer", ResponseNamespace = "https://prodServer")] #else [SoapDocumentMethodAttribute("https://devServer/Service_Test", RequestNamespace = "https://devServer", ResponseNamespace = "https://devServer")] #endif public string Service_Test() { // test service } Though there might be some syntactical sugar that allows me to flip between two attributes of the same type in another fashion, I don't know it. Any ideas? The alternative method would be to reference the entire project instead of the assembly, but I'd rather stick with just referencing the compiled DLL if I can. I'm also completely open to a whole new approach to solve the problem if that's what it takes.

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  • Clarification/explanation of RegisterClientScriptInclude method

    - by mpminnich
    I've been looking on the Internet for a fairly clear explanation of the different methods of registering javascript in an asp.net application. I think I have a basic understating of the difference between registerStartupScript and registerClientScriptBlock (the main difference being where in the form the script is inserted). I'm not sure I understand what the RegisterClientScriptInclude method does or when it is used. From what I can gather, it is used to register an external .js file. Does this then make any and all javascript functions in that file available to the aspx page it was registered on? For example, if it was registered in the onLoad event of a master page, would all pages using that master page be able to use the javascript functions in the .js file? What problems would arise when trying to use document.getElementById in this case, if any? Also, when it is necessary/advantageous to use multiple .js files and register them separately? I appreciate any help you can give. If you know of any really good resources I can use to get a thorough understanding of this concept, I'd appreciate it!

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  • Heapsort not working in Python for list of strings using heapq module

    - by VSN
    I was reading the python 2.7 documentation when I came across the heapq module. I was interested in the heapify() and the heappop() methods. So, I decided to write a simple heapsort program for integers: from heapq import heapify, heappop user_input = raw_input("Enter numbers to be sorted: ") data = map (int, user_input.split(",")) new_data = [] for i in range(len(data)): heapify(data) new_data.append(heappop(data)) print new_data This worked like a charm. To make it more interesting, I thought I would take away the integer conversion and leave it as a string. Logically, it should make no difference and the code should work as it did for integers: from heapq import heapify, heappop user_input = raw_input("Enter numbers to be sorted: ") data = user_input.split(",") new_data = [] for i in range(len(data)): heapify(data) print data new_data.append(heappop(data)) print new_data Note: I added a print statement in the for loop to see the heapified list. Here's the output when I ran the script: `$ python heapsort.py Enter numbers to be sorted: 4, 3, 1, 9, 6, 2 [' 1', ' 3', ' 2', ' 9', ' 6', '4'] [' 2', ' 3', '4', ' 9', ' 6'] [' 3', ' 6', '4', ' 9'] [' 6', ' 9', '4'] [' 9', '4'] ['4'] [' 1', ' 2', ' 3', ' 6', ' 9', '4']` The reasoning I applied was that since the strings are being compared, the tree should be the same if they were numbers. As is evident, the heapify didn't work correctly after the third iteration. Could someone help me figure out if I am missing something here? I'm running Python 2.4.5 on RedHat 3.4.6-9. Thanks, VSN

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  • Java RSA Encrypt using .NET XML Key File - need help

    - by badMonkey
    In .net I have generated the following public key file: <RSAKeyValue> <Modulus>xTSiS4+I/x9awUXcF66Ffw7tracsQfGCn6g6k/hGkLquHYMFTCYk4mOB5NwLwqczwvl8HkQfDShGcvrm47XHKUzA8iadWdA5n4toBECzRxiCWCHm1KEg59LUD3fxTG5ogGiNxDj9wSguCIzFdUxBYq5ot2J4iLgGu0qShml5vwk=</Modulus> <Exponent>AQAB</Exponent> .NET is happy to encrypt using it's normal methods. I am trying to use this key to encode a string in Java and am running into an Arithmetic problem (exception) when I attempt to encrypt the string. The following is the code I am using to encrypt: byte[] modulusBytes = Base64.decode(this.getString(R.string.public_key_modulus)); byte[] exponentBytes = Base64.decode(this.getString(R.string.public_key_exponent)); BigInteger modulus = new BigInteger( modulusBytes ); BigInteger exponent = new BigInteger( exponentBytes); RSAPublicKeySpec rsaPubKey = new RSAPublicKeySpec(modulus, exponent); KeyFactory fact = KeyFactory.getInstance("RSA"); PublicKey pubKey = fact.generatePublic(rsaPubKey); Cipher cipher = Cipher.getInstance("RSA"); cipher.init(Cipher.ENCRYPT_MODE, pubKey); byte[] cipherData = cipher.doFinal( new String("big kitty dancing").getBytes() ); It is the final line in the code block that fails. I have looked at numerous examples and this is the best I could come up with. If it is not obvious, the R.string.public_key_modulus is a copy/paste of the text in the Modulus element, same applies for exponent.

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  • Why won't Internet Explorer (or Chrome) display my 'Loading...' gif but Firefox will?

    - by codeLes
    I have a page that fires several xmlHttp requests (synchronous, plain-vanilla javascript, I'd love to be using jquery thanks for mentioning that). I'm hiding/showing a div with a loading image based on starting/stopping the related javascript functions (at times I have a series of 3 xmlhttp request spawning functions nested). div = document.getElementById("loadingdiv"); if(div) { if(stillLoading) { div.style.visibility='visible'; div.style.display=''; } else { div.style.visibility='hidden'; div.style.display='none'; } } In Firefox this seems to work fine. The div displays and shows the gif for the required processing. In IE/Chrome however I get no such feedback. I am only able to prove that the div/image will even display by putting alert() methods in place with I call the above code, this stops the process and seems to give the browsers in question the window they need to render the dom change. I want IE/Chrome to work like it works in Firefox. What gives?

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  • How to check if a child-object is populated

    - by TheQ
    How can i check if a child-object of a linq-object is populated or not? Example code below. My model have two methods, one joins data, and the other does not: public static Member GetMemberWithPhoto(Guid memberId) { using (DataContext db = new DataContext()) { DataLoadOptions dataLoadOptions = new DataLoadOptions(); dataLoadOptions.LoadWith<Member>(x => x.UserPhoto); db.LoadOptions = dataLoadOptions; var query = from x in db.Members where x.MemberId == memberId select x; return query.FirstOrDefault(); } } public static Member GetMember(Guid memberId) { using (DataContext db = new DataContext()) { var query = from x in db.Members where x.MemberId == memberId select x; return query.FirstOrDefault(); } } Then my control have the following code: Member member1 = Member.GetMemberWithPhoto(memberId); Member member2 = Member.GetMember(memberId); Debug.WriteLine(member1.UserPhoto.ToString()); Debug.WriteLine(member2.UserPhoto.ToString()); The last line will generate a "Cannot access a disposed object" exception. I know that i can get rid of that exception just by not disposing the datacontext, but then the last line will generate a new query to the database, and i don't want that. What i would like is something like: Debug.WriteLine((member1.UserPhoto.IsPopulated()) ? member1.UserPhoto.ToString() : "none"); Debug.WriteLine((member2.UserPhoto.IsPopulated()) ? member2.UserPhoto.ToString() : "none"); Is it possible?

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  • Python: Calling method A from class A within class B?

    - by Tommo
    There are a number of questions that are similar to this, but none of the answers hits the spot - so please bear with me. I am trying my hardest to learn OOP using Python, but i keep running into errors (like this one) which just make me think this is all pointless and it would be easier to just use methods. Here is my code: class TheGUI(wx.Frame): def __init__(self, title, size): wx.Frame.__init__(self, None, 1, title, size=size) # The GUI is made ... textbox.TextCtrl(panel1, 1, pos=(67,7), size=(150, 20)) button1.Bind(wx.EVT_BUTTON, self.button1Click) self.Show(True) def button1Click(self, event): #It needs to do the LoadThread function! class WebParser: def LoadThread(self, thread_id): #It needs to get the contents of textbox! TheGUI = TheGUI("Text RPG", (500,500)) TheParser = WebParser TheApp.MainLoop() So the problem i am having is that the GUI class needs to use a function that is in the WebParser class, and the WebParser class needs to get text from a textbox that exists in the GUI class. I know i could do this by passing the objects around as parameters, but that seems utterly pointless, there must be a more logical way to do this that doesn't using classes seem so pointless? Thanks in advance!

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  • Doing some downloading without blocking you app

    - by Code
    Hi guys, I'm working on my first app that's doing a few different web connections at once. My first screen is my Menu. And at the bottom of viewDidLoad of MenuViewController i call a method that gets and parses a .xml file that is located on my webserver. Also at the bottom of viewDidLoad i do FootballScores = [[FootBallScores alloc] init]; and FootballScores makes a connection to a html page which it loads into a string and then parses out data. Now since both of these are getting called at the bottom of viewDidLoad of the class thats is responsible for the main menu(first screen in the app) it means the app is kinda slow to load. What is the right way to do the above? Should i remove the 2 pieces of code from my viewDidLoad and replace with maybe dataGetterOne = [NSTimer scheduledTimerWithTimeInterval:1.000 target:self selector:@selector(xmlParser) userInfo:nil repeats:NO]; dataGetterTwo = [NSTimer scheduledTimerWithTimeInterval:2.000 target:self selector:@selector(htmlParser) userInfo:nil repeats:NO]; This would mean that the methods get called later on and the viewDidLoad gets to finish before the i try get the data from the web servers. Making 2 connections to we bservers a second apart to quick? Can the iphone handle having 2 connections open at once? I'm really unsure of anything bad/dangerous I am doing in regards to connections. Many Thanks -Code

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  • Need some advice on MVC separation..

    - by Zenph
    I should note I am using Zend Framework. Although this shouldn't affect the concrete answer, it does mean there are several places I can implement my following method (action helper, controller etc). The issue is I have buildOptions() and parseOptions() method which takes $_GET/$_POST variables based on a 'tag' and builds rules which are then used in a select query. An example would be ?modelSort=id&modelOrder=asc The 'model' in the above obviously relates to the particular model, and it used as a 'tag' so that I can for example also have model2Sort and model2Order so there is no conflict between parameters. However, the trouble I am having now is where should these methods go? They are generally dealing with request params. I have been reading a lot about fat model, thin controller. Should this be in an abstract model. My thinking was that if it were, I would do something like: (note, I know I wouldn't call directly like this. Method would be used by child classes) $abstractModel-buildOptions($params); Where 'params' could be anything, like the request parameters $_GET or $_POST: $abstractModel-buildOptions($_GET); Now from what I can see the model is not inherintly dealing with request variables but rather parameters passed to the method. Advice? Where does this method belong? Model, Controller? Specifically on Zend, should it be an action helper, plugin, within an abstract model? Appreciate any advice.

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  • OS-independent Inter-program communication between Python and C

    - by Gyppo
    I have very little idea what I'm doing here, I've never done anything like this before, but a friend and I are writing competing chess programs and they need to be able to communicate to each other. He'll be writing mainly in C, the bulk of mine will be in Python, and I can see a few options: Alternately write to a temp file, or successive temp files. As the communication won't be in any way bulky this could work, but seems like an ugly work-around to me, the programs will have to keep checking for change/new files, it just seems ugly. Find some way of manipulating pipes i.e. mine.py| ./his . This seems like a bit of a dead end. Use sockets. But I don't know what I'd be doing, so could someone give me a pointer to some reading material? I'm not sure if there are OS-independent, language independent methods. Would there have to be some kind of supervisor server program to administrate? Use some kind of HTML protocol, which seems like overkill. I don't mind the programs having to run on the same machine. What do people recommend, and where can I start reading?

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  • Service Layer are repeating my Repositories

    - by Felipe
    Hi all, I'm developing an application using asp.net mvc, NHibernate and DDD. I have a service layer that are used by controllers of my application. Everything are using Unity to inject dependencies (ISessionFactory in repositories, repositories in services and services in controllers) and works fine. But, it's very common I need a method in service to get only object in my repository, like this (in service class): public class ProductService { private readonly IUnitOfWork _uow; private readonly IProductRepository _productRepository; public ProductService(IUnitOfWork unitOfWork, IProductRepository productRepository) { this._uow = unitOfWork; this._productRepository = productRepository; } /* this method should be exists in DDD ??? It's very common */ public Domain.Product Get(long key) { return _productRepository.Get(key); } /* other common method... is correct by DDD ? */ public bool Delete(long key) { usign (var tx = _uow.BeginTransaction()) { try { _productRepository.Delete(key); tx.Commit(); return true; } catch { tx.RollBack(); return false; } } } /* ... others methods ... */ } This code is correct by DDD ? For each Service class I have a Repository, and for each service class need I do a method "Get" for an entity ? Thanks guys Cheers

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  • Pass Arguments to Included Module in Ruby?

    - by viatropos
    I'm hoping to implement something like all of the great plugins out there for ruby, so that you can do this: acts_as_commentable has_attached_file :avatar But I have one constraint: That helper method can only include a module; it can't define any variables or methods. The reason for this is because, I want the options hash to define something like type, and that could be converted into one of say 20 different 'workhorse' modules, all of which I could sum up in a line like this: def dynamic_method(options = {}) include ("My::Helpers::#{options[:type].to_s.camelize}").constantize(options) end Then those 'workhorses' would handle the options, doing things like: has_many "#{options[:something]}" Here's what the structure looks like, and I'm wondering if you know the missing piece in the puzzle: # 1 - The workhorse, encapsuling all dynamic variables module My::Module def self.included(base) base.extend ClassMethods base.class_eval do include InstanceMethods end end module InstanceMethods self.instance_eval %Q? def #{options[:my_method]} "world!" end ? end module ClassMethods end end # 2 - all this does is define that helper method module HelperModule def self.included(base) base.extend(ClassMethods) end module ClassMethods def dynamic_method(options = {}) # don't know how to get options through! include My::Module(options) end end end # 3 - send it to active_record ActiveRecord::Base.send(:include, HelperModule) # 4 - what it looks like class TestClass < ActiveRecord::Base dynamic_method :my_method => "hello" end puts TestClass.new.hello #=> "world!" That %Q? I'm not totally sure how to use, but I'm basically just wanting to somehow be able to pass the options hash from that helper method into the workhorse module. Is that possible? That way, the workhorse module could define all sorts of functionality, but I could name the variables whatever I wanted at runtime.

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  • How to make 2 incompatible types, but with the same members, interchangeable?

    - by Quigrim
    Yesterday 2 of the guys on our team came to me with an uncommon problem. We are using a third-party component in one of our winforms applications. All the code has already been written against it. They then wanted to incorporate another third-party component, by the same vender, into our application. To their delight they found that the second component had the exact same public members as the first. But to their dismay, the 2 components have completely separate inheritance hierarchies, and implement no common interfaces. Makes you wonder... Well, makes me wonder. An example of the problem: public class ThirdPartyClass1 { public string Name { get { return "ThirdPartyClass1"; } } public void DoThirdPartyStuff () { Console.WriteLine ("ThirdPartyClass1 is doing its thing."); } } public class ThirdPartyClass2 { public string Name { get { return "ThirdPartyClass2"; } } public void DoThirdPartyStuff () { Console.WriteLine ("ThirdPartyClass2 is doing its thing."); } } Gladly they felt copying and pasting the code they wrote for the first component was not the correct answer. So they were thinking of assigning the component instant into an object reference and then modifying the code to do conditional casts after checking what type it was. But that is arguably even uglier than the copy and paste approach. So they then asked me if I can write some reflection code to access the properties and call the methods off the two different object types since we know what they are, and they are exactly the same. But my first thought was that there goes the elegance. I figure there has to be a better, graceful solution to this problem.

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  • Parallelizing L2S Entity Retrieval

    - by MarkB
    Assuming a typical domain entity approach with SQL Server and a dbml/L2S DAL with a logic layer on top of that: In situations where lazy loading is not an option, I have settled on a convention where getting a list of entities does not also get each item's child entities (no loading), but getting a single entity does (eager loading). Since getting a single entity also gets children, it causes a cascading effect in which each child then gets its children too. This sounds bad, but as long as the model is not too deep, I usually don't see performance problems that outweigh the benefits of the ease of use. So if I want to get a list in which each of the items is fully hydrated with children, I combine the GetList and GetItem methods. So I'll get a list and then loop through it getting each item with the full cascade. Even this is generally acceptable in many of the projects I've worked on - but I have recently encountered situations with larger models and/or more data in which it needs to be more efficient. I've found that partitioning the loop and executing it on multiple threads yields excellent results. In my first experiment with a list of 50 items from one particular project, I did 5 threads of 10 items each and got a 3X improvement in time. Of course, the mileage will vary depending on the project but all else being equal this is clearly a big opportunity. However, before I go further, I was wondering what others have done that have already been through this. What are some good approaches to parallelizing this type of thing?

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  • Calling base Text method on custom TextBox

    - by The Demigeek
    I'm trying to create a CurrencyTextBox that inherits from TextBox. I'm seeing some really weird behavior that I just don't understand. After lots of testing, I think I can summarize as follows: In the class code, when I access base.Text (to get the textbox's text), I'm actually getting the return value of my overridden Text property. I thought the base keyword would ensure that the underlying object's methods get called. To demonstrate: public class cTestTextBox : System.Windows.Forms.TextBox { string strText = ""; public cTestTextBox() { SetVal("AAA"); base.Text = "TEST"; } public override string Text { get { string s = strText; s = "++" + s + "++"; return s; } } public void SetVal(string val) { strText = val; } } Place this control on a form and set a breakpoint on the constructor. Run the app. Hover your mouse over the base.Text expression. Note that the tooltip shows you the value of the overridden property, not the base property. Execute the SetVal() statement and again hover your mouse over the base.Text expression. Note that the tooltop shows you the value of the overridden property, not the base property. How do I reliably access the Text property of the textbox from which I'm inheriting?

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  • How to have variables with dynamic data types in Java?

    - by Nazgulled
    Hi, I need to have a UserProfile class that it's just that, a user profile. This user profile has some vital user data of course, but it also needs to have lists of messages sent from the user friends. I need to save these messages in LinkedList, ArrayList, HashMap and TreeMap. But only one at a time and not duplicate the message for each data structure. Basically, something like a dynamic variable type where I could pick the data type for the messages. Is this, somehow, possible in Java? Or my best approach is something like this? I mean, have 2 different classes (for the user profile), one where I host the messages as Map<K,V> (and then I use HashMap and TreeMap where appropriately) and another class where I host them as List<E> (and then I use LinkedList and ArrayList where appropriately). And probably use a super class for the UserProfile so I don't have to duplicate variables and methods for fields like data, age, address, etc... Any thoughts?

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  • How do I pass a value to a method in Objective C

    - by user268124
    I'm new to Obj-C and I have run in to a very, very basic mental block that's making me feel a little stupid. I want to pass a variable from one method to another in an purely objective-C way. So far I'm stuck and have resorted to writing it in C. In C it goes as follows; //detect the change in the segmented switch so we can; change text - (IBAction)switchChanged:(id)sender { NSLog(@"Switch change detected"); //grab the info from the sender UISegmentedControl *selector = sender; //grab the selected segment info from selector. This returns a 0 or a 1. int selectorIndex = [selector selectedSegmentIndex]; changeText (selectorIndex); } int changeText (int selectorPosition) { NSLog(@"changeText received a value. Selector position is %d", selectorPosition); //Idea is to receive a value from the segmented controler and change the screen text accordingly return 0; } This works perfectly well, but I want to learn how to do this with objects and messages. How would I rewrite these two methods to do this? Cheers Rich

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  • java template design

    - by Sean Nguyen
    Hi, I have this class: public class Converter { private Logger logger = Logger.getLogger(Converter.class); public String convert(String s){ if (s == null) throw new IllegalArgumentException("input can't be null"); logger.debug("Input = " + s); String r = s + "abc"; logger.debug("Output = " + s); return r; } public Integer convert(Integer s){ if (s == null) throw new IllegalArgumentException("input can't be null"); logger.debug("Input = " + s); Integer r = s + 10; logger.debug("Output = " + s); return r; } } The above 2 methods are very similar so I want to create a template to do the similar things and delegate the actual work to the approriate class. But I also want to easily extends this frame work without changing the template. So for example: public class ConverterTemplate { private Logger logger = Logger.getLogger(Converter.class); public Object convert(Object s){ if (s == null) throw new IllegalArgumentException("input can't be null"); logger.debug("Input = " + s); Object r = doConverter(); logger.debug("Output = " + s); return r; } protected abstract Object doConverter(Object arg); } public class MyConverter extends ConverterTemplate { protected String doConverter(String str) { String r = str + "abc"; return r; } protected Integer doConverter(Integer arg) { Integer r = arg + 10; return r; } } But that doesn't work. Can anybody suggest me a better way to do that? I want to achieve 2 goals: 1. A template that is extensible and does all the similar work for me. 2. I ant to minimize the number of extended class. Thanks,

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  • Is it possible in SQLAlchemy to filter by a database function or stored procedure?

    - by Rico Suave
    We're using SQLalchemy in a project with a legacy database. The database has functions/stored procedures. In the past we used raw SQL and we could use these functions as filters in our queries. I would like to do the same for SQLAlchemy queries if possible. I have read about the @hybrid_property, but some of these functions need one or more parameters, for example; I have a User model that has a JOIN to a bunch of historical records. These historical records for this user, have a date and a debit and credit field, so we can look up the balance of a user at a specific point in time, by doing a SUM(credit) - SUM(debit) up until the given date. We have a database function for that called dbo.Balance(user_id, date_time). I can use this to check the balance of a user at a given point in time. I would like to use this as a criterium in a query, to select only users that have a negative balance at a specific date/time. selection = users.filter(coalesce(Users.status, 0) == 1, coalesce(Users.no_reminders, 0) == 0, dbo.pplBalance(Users.user_id, datetime.datetime.now()) < -0.01).all() This is of course a non-working example, just for you to get the gist of what I'd like to do. The solution looks to be to use hybrd properties, but as I mentioned above, these only work without parameters (as they are properties, not methods). Any suggestions on how to implement something like this (if it's even possible) are welcome. Thanks,

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  • Writing a generic function that can take a Writer as well as an OutputStream

    - by ebruchez
    I wrote a couple of functions that look like this: def myWrite(os: OutputStream) = {} def myWrite(w: Writer) = {} Now both are very similar and I thought I would try to write a single parametrized version of the function. I started with a type with the two methods that are common in the Java OutputStream and Writer: type Writable[T] = { def close() : Unit def write(cbuf: Array[T], off: Int, len: Int): Unit } One issue is that OutputStream writes Byte and Writer writes Char, so I parametrized the type with T. Then I write my function: def myWrite[T, A[T] <: Writable[T]](out: A[T]) = {} and try to use it: val w = new java.io.StringWriter() myWrite(w) Result: <console>:9: error: type mismatch; found : java.io.StringWriter required: ?A[ ?T ] Note that implicit conversions are not applicable because they are ambiguous: both method any2ArrowAssoc in object Predef of type [A](x: A)ArrowAssoc[A] and method any2Ensuring in object Predef of type [A](x: A)Ensuring[A] are possible conversion functions from java.io.StringWriter to ?A[ ?T ] myWrite(w) I tried a few other combinations of types and parameters, to no avail so far. My question is whether there is a way of achieving this at all, and if so how. (Note that the implementation of myWrite will need, internally, to know the type T that parametrizes the write() method, because it needs to create a buffer as in new ArrayT.)

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  • How to acheieve this kind of behaviour in asp.net mvc

    - by kumar
    Hello Friends,, I have this two Action result methods. public ActionResult GetStudentInfo(StudentBE s) { return PartialView("editStudent", s); } public ActionResult GenericList() { StudentBE codes = new StudentBE(); codes.lookcodes= GetStudentCodes(new string[] { "A", "B", "C, "D", "E" }); return PartialView(codes); } // Lookcodes display dropdownlist boxes in the GeneridList view.. In genericList view I hvae beginForm.. <% using (Html.BeginForm("Updatestudent", "expense", FormMethod.Post, new { @id = "id" })) { %> <% } %> so My updatestudent method is [HttpPost] public JsonResult Updatestudent(StudentBE e) { var status = common.Update(e.student); } } return Json(status.ToString()); } Here is my problem.. the GetStudentInfo Actionresult is having each student information.. in UpdateStudent method Update Method calls the DB calls for stored procedure to update each user information now to update each user I need to call GetstudentInfo each time to get student information to update..? how to call GetStudentInfo method here to get studentinformation? student informatin may be multiple that is more than one student informaton... can anybody help me out.. thanks

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  • Is it good practise to blank out inherited functionality that will not be used?

    - by Timo Kosig
    I'm wondering if I should change the software architecture of one of my projects. I'm developing software for a project where two sides (in fact a host and a device) use shared code. That helps because shared data, e.g. enums can be stored in one central place. I'm working with what we call a "channel" to transfer data between device and host. Each channel has to be implemented on device and host side. We have different kinds of channels, ordinary ones and special channels which transfer measurement data. My current solution has the shared code in an abstract base class. From there on code is split between the two sides. As it has turned out there are a few cases when we would have shared code but we can't share it, we have to implement it on each side. The principle of DRY (don't repeat yourself) says that you shouldn't have code twice. My thought was now to concatenate the functionality of e.g. the abstract measurement channel on the device side and the host side in an abstract class with shared code. That means though that once we create an actual class for either the device or the host side for that channel we have to hide the functionality that is used by the other side. Is this an acceptable thing to do: public abstract class MeasurementChannelAbstract { protected void MethodUsedByDeviceSide() { } protected void MethodUsedByHostSide() { } } public class DeviceMeasurementChannel : MeasurementChannelAbstract { public new void MethodUsedByDeviceSide() { base.MethodUsedByDeviceSide(); } } Now, DeviceMeasurementChannel is only using the functionality for the device side from MeasurementChannelAbstract. By declaring all methods/members of MeasurementChannelAbstract protected you have to use the new keyword to enable that functionality to be accessed from the outside. Is that acceptable or are there any pitfalls, caveats, etc. that could arise later when using the code?

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  • Is it better for class data to be passed internally or accessed directly?

    - by AaronSzy
    Example: // access fields directly private void doThis() { return doSomeWork(this.data); } // receive data as an argument private void doThis(data) { return doSomeWork(data); } The first option is coupled to the value in this.data while the second option avoids this coupling. I feel like the second option is always better. It promotes loose coupling WITHIN the class. Accessing global class data willy-nilly throughout just seems like a bad idea. Obviously this class data needs to be accessed directly at some point. However, if accesses, to this global class data can be eliminated by parameter passing, it seems that this is always preferable. The second example has the advantage of working with any data of the proper type, whereas the first is bound to working with the just class data. Even if you don't NEED the additional flexibility, it seems nice to leave it as an option. I just don't see any advantage in accessing member data directly from private methods as in the first example. Whats the best practice here? I've referenced code complete, but was not able to find anything on this particular issue.

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