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• Why Is Java Missing Access Specifiers?

  - by Tom Tresansky

  Does anyone understand why Java is missing: An access specifier which allows access by the class and all subclasses, but NOT by other classes in the same package? (Protected-minus) An access specifier which allows access by the class, all classes in the same package, AND all classes in any sub-package? (Default-plus) An access specifier which adds classes in sub-packages to the entities currently allowed access by protected? (Protected-plus) I wish I had more choices than protected and default. In particular, I'm interested in the Protected-plus option. Say I want to use a Builder/Factory patterned class to produce an object with many links to other objects. The constructors on the objects are all default, because I want to force you to use the factory class to produce instances, in order to make sure the linking is done correctly. I want to group the factories in a sub-package to keep them all together and distinct from the objects they are instantiating---this just seems like a cleaner package structure to me. No can do, currently. I have to put the builders in the same package as the objects they are constructing, in order to gain the access to defaults. But separating project.area.objects from project.area.objects.builders would be so nice. So why is Java lacking these options? And, is there anyway to fake it?

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• Has anyone used ever Mangoslick from themeforest?

  - by bonesnatch

  I was assigned to integrate MangoSlick theme to our current admin panel, Its a jQuery, Slick(?) and Responsive template. First, let me explain how the API goes In the documentation, it only says this is the only way data-[options]=[value] Example: If I wanna make a progress bar I can use this format <div class="progress"> <div class="bar" data-title="[title]" data-value="[value]" data-max="[max]" data-format="[format string]"></div> </div> so filling-in values <div class="progress"> <div class="bar" data-title="Space" data-value="1285" data-max="5120" data-format="0,0 MB"></div> </div> I will have this as output Now, the main question is when I use jQuery attr() to change the attribute values for data-title, data-max, data-value and data-format. Why is it not working? <script> var jq = $.noConflict(); jq(document).ready(function(){ jq('#bokz').attr("data-title", "No Space"); }); </script> Using the script above and inspect element in chrome the values are changed but not in the progressbar Some of you may have some ideas on this? Any help/suggestion would be very much appreciated.

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• Hiding instantiated templates in shared library created with g++

  - by jchl

  I have a file that contains the following: #include <map> class A {}; void doSomething() { std::map<int, A> m; } When compiled into a shared library with g++, the library contains dynamic symbols for all the methods of std::map<int, A>. Since A is private to this file, there is no possibility that std::map will be instantiated in any other shared library with the same parameters, so I'd like to make the template instantiation hidden (for some of the reasons described in this document). I thought I should be able to do this by adding an explicit instantiation of the template class and marking it as hidden, like so: #include <map> class A {}; template class __attribute__((visibility ("hidden"))) std::map<int, A>; void doSomething() { std::map<int, A> m; } However, this has no effect: the symbols are still all exported. I even tried compiling with -fvisibility=hidden, but this also has no effect on the visibility of the methods of std::map<int, A> (although it does hide doSomething). The document I linked to above describes the use of export maps to restrict visibility, but that seems very tedious. Is there a way to do what I want in g++ (other than using export maps)? If so, what is it? If not, is there a good reason why these symbols must always be exported, or is this just a omission in g++?

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• Selecting an option with given value

  - by Maven

  I am trying to select a particular option from a select list depending on the value, I have following markup: <select name="class" id="class"> <option value="1">679460ED-0B15-4ED9-B3C8-A8C276DF1C82</option> <option value="2">B99BF873-7DF0-4E7F-95FF-3F1FD1A26139</option> <option value="3">1DCD5AD7-F57C-414</option> <option value="4">6B0170AA-F044-4F9C-8BB8-31A51E452CE4</option> <option value="5">C6A8B</option> <option value="6">1BBD6FA4-335A-4D8F-8681-DFED317B8052</option> <option value="7">727D71AB-F7D1-4B83-9D6D-6BEEAAB</option> <option value="8">BC4DE8A2-C864-4C7C-B83C-EE2450AF11B1</option> <option value="9">AIR CONDITIONING SYSTEM</option> <option value="10">POWER GENERATION SYSTEM</option> </select> <script> selectThisValue('#class',3); </script> in .js function selectThisValue(element,value) { console.log(value); var elem = $(element + ' option[value=' + value + ']'); console.log(elem); elem.attr("selected", "selected"); } Results for console.log are as follows: 3 [prevObject: i.fn.i.init[1], context: document, selector: "#class option[value=3]", jquery: "1.10.2", constructor: function…] But this is not working, no errors are given but nothing happens also. Please help identifying the where am I wrong.

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• Creating a assertClass() method in JUnit

  - by Mike

  Hi, I'm creating a test platform for a protocol project based on Apache MINA. In MINA when you receive packets the messageReceived() method gets an Object. Ideally I'd like to use a JUnit method assertClass(), however it doesn't exist. I'm playing around trying to work out what is the closest I can get. I'm trying to find something similar to instanceof. Currently I have: public void assertClass(String msg, Class expected, Object given) { if(!expected.isInstance(given)) Assert.fail(msg); } To call this: assertClass("Packet type is correct", SomePacket.class, receivedPacket); This works without issue, however in experimenting and playing with this my interest was peaked by the instanceof operator. if (receivedPacket instanceof SomePacket) { .. } How is instanceof able to use SomePacket to reference the object at hand? It's not an instance of an object, its not a class, what is it?! Once establishing what type SomePacket is at that point is it possible to extend my assertClass() to not have to include the SomePacket.class argument, instead favouring SomePacket?

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• Python, lambda, find minimum

  - by qba

  I have foreach function which calls specified function on every element which it contains. I want to get minimum from thise elements but I have no idea how to write lambda or function or even a class that would manage that. Thanks for every help. I use my foreach function like this: o.foreach( lambda i: i.call() ) or o.foreach( I.call ) I don't like to make a lists or other objects. I want to iterate trough it and find min. I manage to write a class that do the think but there should be some better solution than that: class Min: def __init__(self,i): self.i = i def get_min(self): return self.i def set_val(self,o): if o.val < self.i: self.i = o.val m = Min( xmin ) self.foreach( m.set_val ) xmin = m.get_min() Ok, so I suppose that my .foreach method is non-python idea. I should do my Class iterable because all your solutions are based on lists and then everything will become easier. In C# there would be no problem with lambda function like that, so I though that python is also that powerful.

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• Unit Tests Architecture Question

  - by Tom Tresansky

  So I've started to layout unit tests for the following bit of code: public interface MyInterface { void MyInterfaceMethod1(); void MyInterfaceMethod2(); } public class MyImplementation1 implements MyInterface { void MyInterfaceMethod1() { // do something } void MyInterfaceMethod2() { // do something else } void SubRoutineP() { // other functionality specific to this implementation } } public class MyImplementation2 implements MyInterface { void MyInterfaceMethod1() { // do a 3rd thing } void MyInterfaceMethod2() { // do something completely different } void SubRoutineQ() { // other functionality specific to this implementation } } with several implementations and the expectation of more to come. My initial thought was to save myself time re-writing unit tests with something like this: public abstract class MyInterfaceTester { protected MyInterface m_object; @Setup public void setUp() { m_object = getTestedImplementation(); } public abstract MyInterface getTestedImplementation(); @Test public void testMyInterfaceMethod1() { // use m_object to run tests } @Test public void testMyInterfaceMethod2() { // use m_object to run tests } } which I could then subclass easily to test the implementation specific additional methods like so: public class MyImplementation1Tester extends MyInterfaceTester { public MyInterface getTestedImplementation() { return new MyImplementation1(); } @Test public void testSubRoutineP() { // use m_object to run tests } } and likewise for implmentation 2 onwards. So my question really is: is there any reason not to do this? JUnit seems to like it just fine, and it serves my needs, but I haven't really seen anything like it in any of the unit testing books and examples I've been reading. Is there some best practice I'm unwittingly violating? Am I setting myself up for heartache down the road? Is there simply a much better way out there I haven't considered? Thanks for any help.

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• manipulating radio box selection with javascript

  - by Crays

  Hi guys, i'm trying to do a poll but i designed it without any radio box in it. So i decided to make the selection being highlighted with a different background color, all is done with jquery. I set the display of the radio box to none so that it wouldn't show, gave each a unique ID. Here's the script. <form action="v_poll.php" method="post"> <ul class="voting"> <li class="voting votetext"><input type="radio" name="voting" value="a1" style="display:none;" id="a1"><a onClick="vote('a1')"Answer 1</a></li> <li class="voting votetext"><input type="radio" name="voting" value="a2" style="display:none;" id="a2"><a onClick="vote('a2')">Answer 2</a></li> <li class="voting votetext"><input type="radio" name="voting" value="a3" style="display:none;" id="a3"><a onClick="vote('a3')">Answer 3</a></li> <input type="hidden" value="1" name="id" /> <input type="submit" value="submit"> </ul> </form> <script type="text/javascript"> function vote(TheValue) { GetElementById(TheValue).checked=true; } </script> But when i checked the value of the radio box with $_POST['voting'], it is blank. Not the value assigned to the radio box. Anything i'm doing wrong? Please help. Thanks.

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• Aggregation, Association and Composition (examples of code given)

  - by Bukocen

  I have such a simple example: public class Order { private ArrayList<Product> orders = new ArrayList<Product>(); public void add(Product p) { orders.add(p); } } Is it aggregation or composition? I guess it's composition, because orders will be delated after delete of Order, right? Unfortunately it was a task and answer was different;/ Do you know why? second problem: public class Client extends Person { String adress = ""; Orders orders = new Orders(); public Client(String n, String sn) { name = n; surName = sn; } public String getAddress() { return adress; } public Orders getOrders() { return this.orders; } } Is it Association between Client and Orders? My teacher told me that this is association, but I was wondering why it's not a aggregation/composition - he told me that aggregation or composition occur only when one class contains few instances of different class - is that right? I guess not, because e.g. car contains ONE wheel and it's aggregation I guess? What type of relation is that and why? Greetings

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• Ruby on rails 2 level model

  - by jony17

  I need some help creating a very simple forum in a existing model. What I want in a Game page, have a mini forum, where is possible create some topics and some comments to this topics. In the beginning I'm only implement topics. This is the error I have: Mysql2::Error: Column 'user_id' cannot be null: INSERT INTO `topics` (`game_id`, `question`, `user_id`) VALUES (1, 'asd', NULL) This is my main model: game.rb class Game < ActiveRecord::Base attr_accessible :name validates :user_id, presence: true validates :name, presence: true, length: { maximum: 50 } belongs_to :user has_many :topics, dependent: :destroy end topic.rb class Topic < ActiveRecord::Base validates_presence_of :question validates_presence_of :game_id attr_accessible :question, :user_id validates :question, length: {maximum: 50}, allow_blank: false belongs_to :game belongs_to :user end topic_controller.rb def create @game = Game.find(params[:game_id]) @topic = @game.topics.create(params[:topic]) @topic.user_id = current_user.id respond_to do |format| if @topic.save format.html { redirect_to @game, notice: 'Topic was successfully created.' } else format.html { render action: "new" } end end end game/show.html.erb <h2>Topics</h2> <% @game.topics.each do |topic| %> <p> <b>Question:</b> <%= topic.question %> </p> <% end %> <h2>Add a topic:</h2> <%= form_for([@game, @game.topics.build]) do |f| %> <div class="field"> <%= f.label :question %><br /> <%= f.text_field :question %> </div> <div class="actions"> <%= f.submit %> </div> <% end %> Thanks ;)

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• How do I implement IEnumerable?

  - by Stacey

  I have a class that contains a static number of objects. This class needs to be frequently 'compared' to other classes that will be simple List objects. public partial class Sheet { public Item X{ get; set; } public Item Y{ get; set; } public Item Z{ get; set; } } the items are obviously not going to be "X" "Y" "Z", those are just generic names for example. The problem is that due to the nature of what needs to be done, a List won't work; even though everything in here is going to be of type Item. It is like a checklist of very specific things that has to be tested against in both code and runtime. This works all fine and well; it isn't my issue. My issue is iterating it. For instance I want to do the following... List<Item> UncheckedItems = // Repository Logic Here. UncheckedItems contains all available items; and the CheckedItems is the Sheet class instance. CheckedItems will contain items that were moved from Unchecked to Checked; however due to the nature of the storage system, items moved to Checked CANNOT be REMOVED from Unchecked. I simply want to iterate through "Checked" and remove anything from the list in Unchecked that is already in "Checked". So naturally, that would go like this with a normal list. foreach(Item item in Unchecked) { if( Checked.Contains(item) ) Unchecked.Remove( item ); } But since "Sheet" is not a 'List', I cannot do that. So I wanted to implement IEnumerable so that I could. Any suggestions? I've never implemented IEnumerable directly before and I'm pretty confused as to where to begin.

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• Hide table row onclick using jquery

  - by John

  I have a bunch of table rows such as: <tr> <td>cell1</td> <td>cell2</td> <td><a href="action.php">cell3</a></td> </tr> <tr class="notes_row"> <td colspan="6"> <ul class="message warning no-margin" id="notes_box"> <li>Notes here</li> </ul> </td> </tr> <tr> <td>cell1</td> <td>cell2</td> <td><a href="action.php">cell3</a></td> </tr> The class="notes_row" is only there if notes are present for the row above it. How can I hide the tr and if its there the tr with the notes_row class below it without affecting the other rows using jquery? So if someone clicked cell3 the tr that link is in is hidden then if there is a notes table row below it, it hides that as well.

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• C# / this. and List<T>

  - by user3533030

  I am having trouble understanding how to initialize a List of objects and use it with methods inside of a class. I understand the mechanics of the List, but not how to initialize it inside a method and use it later. For example, I want to have a class that creates the List when it is constructed. Then, I want to use a method of that class to add elements to the list. The elements in the list are objects defined by the SolidWorks API. So, to construct the List, I used... public class ExportPoints : Exporter { public List<SldWorks.SketchPoint> listOfSketchPoints; public ExportPoints(SldWorks.SldWorks swApp, string nameSuffix) : base(swApp, nameSuffix) { List<SldWorks.SketchPoint> listOfSketchPoints = new List<SldWorks.SketchPoint>(); } public void createListOfFreePoints() { try { [imagine more code here] this.listOfSketchPoints.Add(pointTest); } catch (Exception e) { Debug.Print(e.ToString()); return; } } This fails during execution as if the listOfSketchPoints was never initialized as a List. So, I tried a hack and this worked: public ExportPoints(SldWorks.SldWorks swApp, string nameSuffix) : base(swApp, nameSuffix) { List<SldWorks.SketchPoint> listOfSketchPoints = new List<SldWorks.SketchPoint>(); this.listOfSketchPoints = listOfSketchPoints; } This approach creates the behavior that I want. However, it seems that I lack some understanding as to why this is necessary. Shouldn't it be possible to "initialize" a List that is a property of your object with a constructor? Why would you need to create the list, then assign the pointer of that new List to your property?

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• How is covariance cooler than polymorphism...and not redundant?

  - by P.Brian.Mackey

  .NET 4 introduces covariance. I guess it is useful. After all, MS went through all the trouble of adding it to the C# language. But, why is Covariance more useful than good old polymorphism? I wrote this example to understand why I should implement Covariance, but I still don't get it. Please enlighten me. using System; using System.Collections.Generic; using System.Linq; using System.Text; namespace Sample { class Demo { public delegate void ContraAction<in T>(T a); public interface IContainer<out T> { T GetItem(); void Do(ContraAction<T> action); } public class Container<T> : IContainer<T> { private T item; public Container(T item) { this.item = item; } public T GetItem() { return item; } public void Do(ContraAction<T> action) { action(item); } } public class Shape { public void Draw() { Console.WriteLine("Shape Drawn"); } } public class Circle:Shape { public void DrawCircle() { Console.WriteLine("Circle Drawn"); } } public static void Main() { Circle circle = new Circle(); IContainer<Shape> container = new Container<Circle>(circle); container.Do(s => s.Draw());//calls shape //Old school polymorphism...how is this not the same thing? Shape shape = new Circle(); shape.Draw(); } } }

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• NoMethodError / undefined method `foobar_path' when using form_for

  - by user1850886

  I'm using form_for to create a chatroom and when I view the page I get the following error: NoMethodError in Chatrooms#new undefined method `chatrooms_path' for #<#<Class:0xa862b94>:0xa5307f0> Here's the code for the view, located in app/views/chatrooms/new.html.erb: <div class="center"> <%= form_for(@chatroom) do |f| %> <%=f.text_field :topic%> <br> <%=f.submit "Start a discussion", class: "btn btn-large btn-primary"%> <% end %> </div> Here's the relevant controller: class ChatroomsController < ApplicationController def new @chatroom = Chatroom.new end def show @chatroom = Chatroom.find(params[:id]) end end If I change the line <%= form_for(@chatroom) do |f| %> to <%= form_for(:chatroom) do |f| %> it works fine. I've searched around for similar questions but none of the solutions have worked for me. Help?

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• jquery problem with toggle event only fireing on the 2nd click...

  - by Ronedog

  Can anyone explain why the following jquery only fires the 2nd toggle event and how to fix it? Specifically, every time I click the nested < a element it brings up the alert "2nd click". I tested the selector to make sure it was selecting the element properly and it does, or at least it inserted a class without any problems. The selector is selecting the very last node in the unordered list that has an anchor tag. $("#nav li:not(:has(li)) a").toggle(function() { //1st click alert("1st Click"); }, function() { //2nd click alert("2nd Click"); }); Nested HTML structure that fails: <ul id="nav"> <li> <span>stuff</span> <a href="#">Cat 1</a> <ul> <li> <span>stuff</span> <a href="#">Subcat1</a> <ul> <li> <span>Stuff</span> <a href="#">Subcat Details</a> </li> </ul> </li> </ul> </li> </ul> However, this works right and fires both click events: <ul id="nav"> <li> <span>stuff</span> <a href="#">Cat 1</a> </li> </ul>

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• Using CSS to create three boxes with dividers and text centered within each box

  - by linnse

  I'm trying to figure out the best way to create a row of three boxes (columns), with dividers between boxes 1 and 2, and boxes 2 and 3. The text would need to be centered within each box. h2 { color: #00ADEF; margin-top:0; margin-bottom:0; font-family:Arial, Helvetica, sans-serif; font-size:20px; font-weight:bold; line-height:23px; } p { margin-top:0; } .3colwrapper { width: 930px; margin: 0 auto; } .colbox { float:left; margin: 10px; width: 210px; background:#DDD; padding:10px 40px; } <div class="3colwrapper"> <div class="colbox"><h2>Step One</h2> <p>Sign up</p> </div> <div class="colbox"><h2>Step Two</h2> <p>Verify</p> </div> <div class="colbox"><h2>Step Three</h2> <p>Participate</p> </div> </div> Here's what I've worked up so far: http://cssdesk.com/YyjAr

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• How to determine number of function arguments dynamically

  - by Kam

  I have the following code: #include <iostream> #include <functional> class test { public: typedef std::function<bool(int)> Handler; void handler(Handler h){h(5);} }; class test2 { public: template< typename Ret2, typename Ret, typename Class, typename Param> inline Ret2 MemFn(Ret (Class::*f)(Param), int arg_num) { if (arg_num == 1) return std::bind(f, this, std::placeholders::_1); } bool f(int x){ std::cout << x << std::endl; return true;} }; int main() { test t; test2 t2; t.handler(t2.MemFn<test::Handler>(&test2::f, 1)); return 0; } It works as expected. I would like to be able to call this: t.handler(t2.MemFn<test::Handler>(&test2::f)); instead of t.handler(t2.MemFn<test::Handler>(&test2::f, 1)); Basically I need MemFn to determine in runtime what Handler expects as the number of arguments. Is that even possible?

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• Hibernate Relationship Mapping/Speed up batch inserts

  - by manyxcxi

  I have 5 MySQL InnoDB tables: Test,InputInvoice,InputLine,OutputInvoice,OutputLine and each is mapped and functioning in Hibernate. I have played with using StatelessSession/Session, and JDBC batch size. I have removed any generator classes to let MySQL handle the id generation- but it is still performing quite slow. Each of those tables is represented in a java class, and mapped in hibernate accordingly. Currently when it comes time to write the data out, I loop through the objects and do a session.save(Object) or session.insert(Object) if I'm using StatelessSession. I also do a flush and clear (when using Session) when my line count reaches the max jdbc batch size (50). Would it be faster if I had these in a 'parent' class that held the objects and did a session.save(master) instead of each one? If I had them in a master/container class, how would I map that in hibernate to reflect the relationship? The container class wouldn't actually be a table of it's own, but a relationship all based on two indexes run_id (int) and line (int). Another direction would be: How do I get Hibernate to do a multi-row insert?

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• PHP: cannot matching string "<br />

  - by Patrick

  hi, I'm having problems with string matching in PHP. I've 2 html elements in my page, I've copy pasted here the content with Firebug <div class="field-item odd"> <div class="field-label-inline-first"> Year:</div> 2009 </div> <div class="field-item odd"> <div class="field-label-inline-first"> Synopsis:</div> &lt;br /&gt; </div> This php line works perfectly (the element with 2009 is detected) <?php if ($items[0]['view'] == '2009') : echo "ok"; ?> However I'm not able to match the string containing element: <?php if ($items[0]['view'] == '<br />') : echo "ok"; ?> //doesn't work <?php if ($items[0]['view'] == '&lt;br /&gt;') : echo "ok"; ?> //again doesn't work any tip ? To give you some context: The strings are produced by CKEditor, an editor I'm using in my Drupal back-end. When I leave empty this editor, the tag is displayed on the string as plain text (because I set "plain text" as formatting option in the back-end) Thanks

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• VB.NET: WithEvents not Working

  - by Hei

  Hello All, I have the following classes: Public Class Email Private Shared ReadOnly EMAIL_REGEX = "\b[a-zA-Z]+[a-zA-Z0-9._+-]+@" + _ "[a-zA-Z0-9.-]+\.[a-zA-Z]{2,3}\b" Private _email As String Public Event emailCreated() ' Declare empty constructor private so the only way to create an object ' is using new (email) Private Sub New() End Sub Sub New(ByVal email As String) If Regex.IsMatch(email, EMAIL_REGEX) Then _email = email RaiseEvent emailCreated() Else Throw New Exception("Email Not Valid") End If End Sub ReadOnly Property Email() As String Get Return _email End Get End Property End Class And Public Class EmailForm WithEvents myEmail As Email Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click Try myEmail = New Email(TextBox1.Text) Catch ex As Exception MessageBox.Show("Exception: " & ex.Message) End Try End Sub Public Sub emailCreated() Handles myEmail.emailCreated MessageBox.Show("New Email Created") End Sub End Class If a create a wrong email lets say "email" the exception is correctly cached and a message is showed however is i input a valid email the event is not raised, the object is being created but no message is shown and no error or exception is thrown i suspect it has something to do with using "myemail = new Email(email)" but i have seen examples of using new with withevents with no problem. I would apreciate any input about this problem thank you

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• Location of DB models in Zend Framework - want them centralized

  - by jeffkolez

  Maybe I've been staring at the problem too long and it's much simpler than I think, but I'm stuck right now. I have three websites that are going to share database models. I've structured my applications so that I have an application directory for each site and a public directory for each site. The DB models live in a directory in the library along with Zend Framework and my third party libraries. I use the Autoloader class and when I try to instantiate one of my DB classes, it fails. The library directory is in my include path, but for whatever reason it refuses to instantiate my classes. It will work if I have my models in my application directory, but that's not the point. They're supposed to be shared classes in a Library. $model = new Model_Login(); $model->hello_world(); This fails when its in the library. The class is just a test: class Model_Login { public function hello_world() { echo "hello world"; } } Everything works until I try to instantiate one of my models. I've even tried renaming the class to something else (Db_Login), but that doesn't work either. Any ideas? Thanks in advance.

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• Correct way to initialize dynamic Array in C++

  - by mef

  Hey guys, I'm currently working on a C++ project, where dynamic arrays often appear. I was wondering, what could be the correct way to initialize a dynamic array using the new-operator? A colleague of mine told me that it's a no-no to use new within the constructor, since a constructor is a construct that shouldn't be prone to errors or shouldn't fail at all, respectively. Now let's consider the following example: We have two classes, a more or less complex class State and a class StateContainer, which should be self-explained. class State { private: unsigned smth; public: State(); State( unsigned s ); }; class StateContainer { private: unsigned long nStates; State *states; public: StateContainer(); StateContainer( unsigned long n ); virtual ~StateContainer(); }; StateContainer::StateContainer() { nStates = SOME_DEFINE_N_STATES; states = new State[nStates]; if ( !states ) { // Error handling } } StateContainer::StateContainer( unsigned long n ) { nStates = n; try { states = new State[nStates] } catch ( std::bad_alloc &e ) { // Error handling } } StateContainer::~StateContainer() { if ( states ) { delete[] states; states = 0; } } Now actually, I have two questions: 1.) Is it ok, to call new within a constructor, or is it better to create an extra init()-Method for the State-Array and why? 2.) Whats the best way to check if new succeeded: if (!ptr) std::cerr << "new failed." or try { /*new*/ } catch (std::bad_alloc) { /*handling*/ } 3.) Ok its three questions ;o) Under the hood, new does some sort of ptr = (Struct *)malloc(N*sizeof(Struct)); And then call the constructor, right?

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• Hibernate many-to-many relationship

  - by Capitan

  I have two mapped types, related many-to-many. @Entity @Table(name = "students") public class Student{ ... @ManyToMany(fetch = FetchType.EAGER) @JoinTable( name = "students2courses", joinColumns = { @JoinColumn( name = "student_id", referencedColumnName = "_id") }, inverseJoinColumns = { @JoinColumn( name = "course_id", referencedColumnName = "_id") }) public Set<Course> getCourses() { return courses; } public void setCourses(Set<Course> courses) { this.courses = courses; } ... } __ @Entity @Table(name = "courses") public class Course{ ... @ManyToMany(fetch = FetchType.EAGER, mappedBy = "courses") public Set<Student> getStudents() { return students; } public void setStudents(Set<Student> students) { this.students = students; } ... } But if I update/delete Course entity, records are not created/deleted in table students2courses. (with Student entity updating/deleting goes as expected) I wrote abstract class HibObject public abstract class HibObject { public String getRemoveMTMQuery() { return null; } } which is inherited by Student and Course. In DAO I added this code (for delete() method): String query = obj.getRemoveMTMQuery(); if (query != null) { session.createSQLQuery(query).executeUpdate(); } and I ovrerided method getRemoveMTMQuery() for Course @Override @Transient public String getRemoveMTMQuery() { return "delete from students2courses where course_id = " + id + ";"; } Now it works but I think it's a bad code. Is there a best way to solve this problem?

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• How to delete Drawn Line in java?

  - by Jeyjey

  Hello Folks, well this is my code: import javax.swing.; import javax.; import java.awt.; import java.awt.Color; import java.awt.Graphics.; import java.awt.event.*; import javax.swing.UIManager; public class SimpleGUI extends JFrame{ public SimpleGUI(){ this.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE) ; } public void go(){ Drawpanel = new Mypanel(); JFrame frame = new JFrame("Chasing Line"); frame.getContentPane().add(BorderLayout.CENTER, Drawpanel); frame.setSize(300,300); frame.setVisible(true); Drawpanel.addMouseMotionListener(new java.awt.event.MouseMotionAdapter() { public void mouseMoved(java.awt.event.MouseEvent evt) { DrawpanelMouseMoved(evt); } }); } public void DrawpanelMouseMoved(java.awt.event.MouseEvent evt) { xpos=evt.getX(); ypos=evt.getY(); System.out.println("Coordinates : X :"+ xpos+"Y: "+ypos); Drawpanel.paintImage(xpos,ypos); } class Mypanel extends JPanel{ public void paintImage(int xpost,int ypost){ Graphics d = getGraphics(); d.setColor(Color.black); d.drawLine(xpost, 0, xpost, this.getHeight()); d.setColor(Color.red); d.drawLine(0, ypost, this.getWidth(),ypost); this.validate(); } } // end the inner class public static void main(String[] args){ try { UIManager.setLookAndFeel("com.sun.java.swing.plaf.windows.WindowsLookAndFeel"); } catch(Exception e) { System.err.println("Look and feel not set"); } SimpleGUI win = new SimpleGUI(); win.go(); } Mypanel Drawpanel; private int xpos=0; private int ypos=0; } // close SimpleGUI class The problem is how can i delete the old lines?, i mea,make only the current x and y lines appear on the screen, make the intersection between both lines "follow" the mouse pointer. thanks for any reply.

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