Search Results

Search found 45151 results on 1807 pages for 'dbix class'.

Page 419/1807 | < Previous Page | 415 416 417 418 419 420 421 422 423 424 425 426  | Next Page >

  • Django ModelForm Imagefield Upload

    - by Wei Xu
    I am pretty new to Django and I met a problem in handling image upload using ModelForm. My model is as following: class Project(models.Model): name = models.CharField(max_length=100) description = models.CharField(max_length=2000) startDate = models.DateField(auto_now_add=True) photo = models.ImageField(upload_to="projectimg/", null=True, blank=True) And the modelform is as following: class AddProjectForm(ModelForm): class Meta: model = Project widgets = { 'description': Textarea(attrs={'cols': 80, 'rows': 50}), } fields = ['name', 'description', 'photo'] And the View function is: def addProject(request, template_name): if request.method == 'POST': addprojectform = AddProjectForm(request.POST,request.FILES) print addprojectform if addprojectform.is_valid(): newproject = addprojectform.save(commit=False) print newproject print request.FILES newproject.photo = request.FILES['photo'] newproject.save() print newproject.photo else: addprojectform = AddProjectForm() newProposalNum = projectProposal.objects.filter(solved=False).count() return render(request, template_name, {'addprojectform':addprojectform, 'newProposalNum':newProposalNum}) the template is: <form class="bs-example form-horizontal" method="post" action="">{% csrf_token %} <h2>Project Name</h2><br> {{ addprojectform.name }}<br> <h2>Project Description</h2> {{ addprojectform.description }}<br> <h2>Image Upload</h2><br> {{ addprojectform.photo }}<br> <input type="submit" class="btn btn-success" value="Add Project"> </form> Can anyone help me or could you give an example of image uploading? Thank you!

    Read the article

  • Getting list of fields back from 'use fields' pragma?

    - by makenai
    So I'm familiar with the use fields pragma in Perl that can be used to restrict the fields that are stored in a class: package Fruit; use fields qw( color shape taste ); sub new { my ( $class, $params ) = @_; my $self = fields::new( $class ) unless ref $class; foreach my $name ( keys %$params ) { $self->{ $name } = $params->{ $name }; } return $self; } My question is.. once I've declared the fields at the top, how I can get the list back.. say because I want to generate accessors dynamically? Is keys %FIELDS the only way? Secondarily, is there a more efficient way to pre-populate the fields in the constructor than looping through and assigning each parameter as I am above? Thanks!

    Read the article

  • How to access the map returned by IParameterValues::getParameterValues()?

    - by Hua
    I declared a command and a commandParameter for this command. I specified the "values" of this commandParameter as a class implemented by myself. The implementation of this class is below, public class ParameterValues implements IParameterValues { @Override public Map<String, Double> getParameterValues() { // TODO Auto-generated method stub Map<String, Double> values = new HashMap<String, Double>(2); values.put("testParam", 1.1239); values.put("AnotherTest", 4.1239); return values; } } The implementation of the handler of this command is blow, public class testHandler extends AbstractHandler implements IHandler { private static String PARAMETER_ID = "my.parameter1"; @Override public Object execute(ExecutionEvent event) throws ExecutionException { String value = event.getParameter(PARAMETER_ID); MessageDialog.openInformation(HandlerUtil.getActiveShell(event), "Test", "Parameter ID: " + PARAMETER_ID + "\nValue: " + value); return null; } } Now, I contribute the command to a menu, <menuContribution locationURI="menu:org.eclipse.ui.main.menu"> <menu id="my.edit" label="Edit"> <command commandId="myCommand.test" label="Test1"> <parameter name="my.parameter1" value="testParam"> </parameter> </command> Since I specified a "values" class for the commandParater, I expect when the menu is clicked, this code line "String value = event.getParameter(PARAMETER_ID);" in the handler class returns 1.1239 instead of "testParam". But, I still see that code line returns "testParam". What's the problem? How could I access the map returned by getParameterValues()? By the way, following menu declaration still works even I don't define "ppp" in the map. <menuContribution locationURI="menu:org.eclipse.ui.main.menu"> <menu id="my.edit" label="Edit"> <command commandId="myCommand.test" label="Test1"> <parameter name="my.parameter1" value="ppp"> </parameter> </command> Thanks!

    Read the article

  • JQuery quiz app - use <id> tag to toggle variable on/off

    - by hairyllama
    Hi, I am writing a jquery phonegap quiz app and have a number of categories from which a user can select via checkbox. Relevant questions belonging to those categories are then returned. However, I have two huge switch statements to change the relevant variables from 0 to 1 if the checkbox for that category is selected and vice versa (this info is used to build a compound db query). The value of the variable behind the checkbox is only ever 0 or 1, so is there a better way to do this? My HTML is: <h2>Categories</h2> <ul class="rounded"> <li>Cardiology<span class="toggle"><input type="checkbox" id="cardiology" /></span></li> <li>Respiratory<span class="toggle"><input type="checkbox" id="respiratory" /></span></li> <li>Gastrointestinal<span class="toggle"><input type="checkbox" id="gastrointestinal" /></span></li> <li>Neurology<span class="toggle"><input type="checkbox" id="neurology" /></span></li> </ul> My Javascript is along the lines of: var toggle_cardiology = 0; var toggle_respiratory = 0; var toggle_gastrointestinal = 0; var toggle_neurology = 0; $(function() { $('input[type="checkbox"]').bind('click',function() { if($(this).is(':checked')) { switch (this.id) { case "cardiology": toggle_cardiology = 1; break; case "respiratory": toggle_respiratory = 1; break; case "gastrointestinal": toggle_gastrointestinal = 1; break; case "neurology": toggle_neurology = 1; break; etc. (which is cumbersome with 10+ categories plus an else statement with a switch to change them back) I'm thinking of something along the lines of concatenating the HTML id tag onto the "toggle_" prefix - in pseudocode: if (toggle_ + this.id == 1){ toggle_ + this.id == 0} if (toggle_ + this.id == 0){ toggle_ + this.id == 1} Thanks, Nick.

    Read the article

  • JDOQL Any way to avoid multiple .contains() calls in the query when searching for the presence of on

    - by Finbarr
    The question pretty much says it all. If I have a class Class A public class A { ... private List<String> keys; ... } And I want to select all A instances from the DataStore that have atleast one of a List of keys, is there a better way of doing it than this: query = pm.newQuery(A.class); query.setFilter("keys.contains(:key1) || keys.contains(:key2) || keys.contains(:key3)"); List<A> results = (List<A>)query.execute(key1, key2, key3); This has not yet been implemented, so I am open to radical suggestions.

    Read the article

  • Hibernate Annotation for Entity existing in more than 1 catalog

    - by user286395
    I have a Person entity mapped by Hibernate to a database table in a database catalog "Active". After a period of time, records in this database table in the "Active" catalog are archived/moved to an exact copy of the table in a database Catalog "History". I have the need to retrieve from both the Active and History Catalogs. Is there a better way to model this with Hibernate annotations than making an abstract class that 2 classes extend from. This is what I have now. @MappedSuperclass public abstract class Person { @Id private Integer id; private String name; } @Entity @Table(name="Person", catalog="Active") public class PersonActive extends Person { } @Entity @Table(name="Person", catalog="History") public class PersonHistory extends Person { }

    Read the article

  • Elements of a Java Object Array are created but without correct names

    - by Greenhouse Gases
    Hi all Im having rather an annoying problem. I have a class called Person and a class called Event which serve to create objects to be used for competitors that compete in a certain event. When I add a competitor thats fine and the GUI list updates accordingly, however when I add an event the element in the array does not take on the value of the instance variable name in the class Event and so the GUI does not show the event name, though it is being added in the array correctly. How can I make it so that the event object in each element of the listOfEvents array (which is an array of event objects) has the name of the event. I should add this is for university though this isnt the part for which we will be assessed, it is somethign i have come across and due to not being able to see the code for the GUI, I've hit the proverbial brick wall. I wont include the whole load of code Ive been writing but hopefully my description and snippets below will suffice. Any advice I would appreciate greatly. No doubt I have overlooked something simple! Many thanks. listOfEvents is declared as: Event[] listOfEvents = new Event[20]; A snippet from the Event class: public class Event { String name; Person[] participants = new Person[10]; // array of competitors for the event public Event(String name) { this.name = name; } } and its use in the addEvent method (p is a global variable): public void addEvent(String eventName) { listOfEvents[p] = new Event(eventName); p++; }

    Read the article

  • How to implement a private virtual function within derived classes?

    - by Dane
    Hi, I know why I want to use private virtual functions, but how exactly can I implement them? For example: class Base{ [...] private: virtual void func() = 0; [...] } class Derived1: puplic Base{ void func() { //short implementation is ok here } } class Derived2: puplic Base{ void func(); //long implementation elsewhere (in cpp file) } [...] void Derived2::func() { //long implementation } The first version is ok but not always possible. Isn't the second version simply name hiding? How do you define the Base::func() of Derived2, if you cannot do it within the class declaration of Dereived2? Thanks

    Read the article

  • Using an empty column as a divider in a JTable.

    - by Catalina Island
    I'm trying to use an empty column as a divider between pairs of columns in a JTable. Here's a picture and code for what I have so far. I know I can change the look using a custom TableCellRenderer. Before I go down that road, is there a better way to do this? Any ideas appreciated. import javax.swing.*; import javax.swing.table.*; public class TablePanel extends JPanel { public static void main(String[] args) { SwingUtilities.invokeLater(new Runnable() { @Override public void run() { JFrame f = new JFrame("TablePanel"); f.setDefaultCloseOperation(JFrame.DISPOSE_ON_CLOSE); f.add(new TablePanel()); f.pack(); f.setVisible(true); } }); } public TablePanel() { TableModel dataModel = new MyModel(); JTable table = new JTable(dataModel); table.getColumnModel().getColumn(MyModel.DIVIDER).setMaxWidth(0); JScrollPane jsp = new JScrollPane(table); jsp.setVerticalScrollBarPolicy(JScrollPane.VERTICAL_SCROLLBAR_ALWAYS); this.add(jsp); } private static class MyModel extends AbstractTableModel { private static final int DIVIDER = 2; private final String[] names = { "A1", "A2", "", "B1", "B2" }; @Override public int getRowCount() { return 32; } @Override public int getColumnCount() { return names.length; } @Override public String getColumnName(int col) { if (col == DIVIDER) return ""; return names[col]; } @Override public Object getValueAt(int row, int col) { if (col == DIVIDER) return ""; return (row + 1) / 10.0; } @Override public Class<?> getColumnClass(int col) { if (col == DIVIDER) return String.class; return Number.class; } } }

    Read the article

  • Alternate colors on click with jQuery

    - by Jace Cotton
    I'm sure there is a simple solution to this, and I'm sure this is a duplicate question, though I have been unable to solve my solution particularly because I don't really know how to phrase it in order to search for other questions/solutions, so I'm coming here hoping for some help. Basically, I have spans with classes that assigns a background-color property, and inside those spans are words. I have three of these spans, and each time a user clicks on a span I want the class to change (thus changing the background color and inner text). HTML: <span class="alternate"> <span class="blue showing">Lorem</span> <span class="green">Ipsum</span> <span class="red">Dolor</span> </span> CSS: .alternate span { display : none } .alternate .showing { display : inline } .blue { background : blue } .green { background : green } .red { background : red } jQuery: $(".alternate span").each(function() { $(this).on("click", function() { $(this).removeClass("showing"); $(this).next().addClass("showing"); }); }); This solution works great using $.next until I get to the third click, whereafter .showing is removed, and is not added since there are no more $.next options. How do I, after getting to the last-child, add .showing to the first-child and then start over? I have tried various options including if($(".alternate span:last-child").hasClass("showing")) { etc. etc. }, and I attempted to use an array and for loop though I failed to make it work. Newb question, I know, but I can't seem to solve this so as a last resort I'm coming here.

    Read the article

  • Get value of selected field from a dropdown list

    - by 47
    I have this class in my model: class ServiceCharge(models.Model): name = models.CharField(max_length=30) amount = models.PositiveIntegerField() extends_membership = models.BooleanField(default=False) def __unicode__(self): return str(self.name) What I want to have is in the form for charging users a service charge, when a charge is selected from the dropdown menu, the two values for amount and extends_membership are updated on the form depending on the selected charge. My forms.py: class vModelChoiceField(forms.ModelChoiceField): def label_from_instance(self, obj): return "%s" % obj.name class PayServiceChargeForm(PaymentsForm): service_charge = vModelChoiceField(queryset=ServiceCharge.objects.all(), empty_label=" ") class Meta(PaymentsForm.Meta): exclude = ('member', 'payment_type', 'transacted_by', 'description') Then the form template: <table border="0"> <tr> <td><strong>{% trans "Service Charge" %}</strong></td> <td>{{ form.service_charge }}</td> <td><strong>{% trans "Extends Membership" %}</strong></td> <td>{{ form.extends_membership }}</td> </tr> <tr> <td valign="top"><strong>{% trans "Expiry Date" %}</strong></td> <td valign="top">{{ form.expiry_date }}</td> <td valign="top"><strong>{% trans "Amount" %}</strong></td> <td>{{ form.amount }}</td> </tr> </table> I was trying out some jQuery but I got stuck after getting the currently selected charge: <script type="text/javascript"> $(document).ready(function(){ $("#id_service_charge").change(onSelectChange); }); function onSelectChange(){ var selected = $("#id_service_charge option:selected"); var output = ""; if(selected.val() != 0){ charge = selected.val(); .... (update values) .... } } </script>

    Read the article

  • Loop results executing twice

    - by ozzysmith
    I creating a simple site with PHP where the users can submit blogs and other users (who are logged in) can post comments on them. I have made a link called "comments" below each blog that when clicked will show / hide all the comments relevant to the specific blog (also if the user is logged in, it will show a form field in which they can submit new comments). So basically each blog will have multiple comments. I have done two different codes for this but they both have the same problem that each comment appears twice (everything else works fine). Could anyone point out why? mysql_select_db ("ooze"); $result = mysql_query ("select * from blog") or die(mysql_error()); $i = 1; while($row = mysql_fetch_array($result)) { echo "<h1>$row[title]</h1>"; echo "<p class ='second'>$row[blog_content]</p> "; echo "<p class='meta'>Posted by .... &nbsp;&bull;&nbsp; $row[date] &nbsp;&bull;&nbsp; <a href='#' onclick=\"toggle_visibility('something$i'); return false\">Comments</a><div id='something$i' style='display: none;'>"; $i++; $a = $row["ID"]; $result2 = mysql_query ("select * from blog, blogcomment where $a=blogID") or die(mysql_error()); while($sub = mysql_fetch_array($result2)) { echo "<p class='third' >$sub[commentdate] &nbsp;&bull;&nbsp; $sub[username]</p><p>said:</p> <p>$sub[comment]</p>"; } if ( isset ($_SESSION["gatekeeper"])) { echo '<form method="post" name="result_'.$row["ID"].'" action="postcomment.php"><input name="ID" type = "hidden" value = "'.$row["ID"].'" /><input name="comment" id="comment" type="text" style="margin-left:20px;"/><input type="submit" value="Add comment" /></form>'; } else { echo '<p class="third"><a href="register.html">Signup </a>to post a comment</p>'; } echo "</div>"; } mysql_close($conn); //second version of inner loop:// if ( isset ($_SESSION["gatekeeper"])) { while($sub = mysql_fetch_array($result2)) { echo "<p class='third' >$sub[commentdate] &nbsp;&bull;&nbsp; $sub[username] said:</p> <p>$sub[comment]</p>"; } echo '<form method="post" name="result_'.$row["ID"].'" action="postcomment.php"><input name="ID" type = "hidden" value = "'.$row["ID"].'" /><input name="comment" id="comment" type="text" style="margin-left:20px;"/><input type="submit" value="Add comment" /></form>'; } else { while($sub = mysql_fetch_array($result2)) { echo "<p class='third' >$sub[commentdate] &nbsp;&bull;&nbsp; $sub[username] said:</p> <p>$sub[comment]</p>"; } echo '<p class="third"><a href="register.html">Signup </a>to post a comment</p>'; } echo "</div>"; } mysql_close($conn);

    Read the article

  • Why is this Scala example of implicit paremeter not working?

    - by Alex R
    simple REPL test... def g(a:Int)(implicit b:Int) = {a+b} Why do neither of these attempted usages work? 1. scala class A { var b:Int =8; var c = g(2) } :6: error: could not find implicit value for parameter b: Int class A { var b:Int =8; var c = g(2) } 2. scala class A(var b:Int) { var c = g(2) } :6: error: could not find implicit value for parameter b: Int class A(var b:Int) { var c = g(2) } ^ Thanks

    Read the article

  • Zend Framework Handle One to Many

    - by user192344
    I have 2 tables "user", "contact", the relation between two tables is one user has many contact Table member m_id name ------------ Table Contact c_id c_m_id value in zend model class, i do it in this way /* Member.php */ class Default_Model_DbTable_Member extends Zend_Db_Table_Abstract { protected $_name = 'member'; protected $_dependentTables = array('Default_Model_DbTable_Contact'); } /* Contact.php */ class Default_Model_DbTable_Contact extends Zend_Db_Table_Abstract { protected $_name = 'contact'; protected $_referenceMap = array( 'Member' => array( 'columns'=> array('c_id'), 'refTableClass'=> 'Default_Model_DbTable_Member', 'refColumns'=> array('c_m_id') ) ); /* IndexController.php */ class IndexController extends Zend_Controller_Action { public function indexAction() { $m= new Default_Model_DbTable_Member(); $row = $m->find(1); $data = $row->current(); $data = $data->findDependentRowset('Default_Model_DbTable_Contact'); print_r($data->toArray()); } } But i just get Invalid parameter number: no parameters were bound , my goal is to search a member detail record, and it also contains a array which store all contact info (i can use join method to do that, but i just want to try zend feature)

    Read the article

  • Directly Jump to another C++ function

    - by maligree
    I'm porting a small academic OS from TriCore to ARM Cortex (Thumb-2 instruction set). For the scheduler to work, I sometimes need to JUMP directly to another function without modifying the stack nor the link register. On TriCore (or, rather, on tricore-g++), this wrapper template (for any three-argument-function) works: template< class A1, class A2, class A3 > inline void __attribute__((always_inline)) JUMP3( void (*func)( A1, A2, A3), A1 a1, A2 a2, A3 a3 ) { typedef void (* __attribute__((interrupt_handler)) Jump3)( A1, A2, A3); ( (Jump3)func )( a1, a2, a3 ); } //example for using the template: JUMP3( superDispatch, this, me, next ); This would generate the assembler instruction J (a.k.a. JUMP) instead of CALL, leaving the stack and CSAs unchanged when jumping to the (otherwise normal) C++ function superDispatch(SchedulerImplementation* obj, Task::Id from, Task::Id to). Now I need an equivalent behaviour on ARM Cortex (or, rather, for arm-none-linux-gnueabi-g++), i.e. generate a B (a.k.a. BRANCH) instruction instead of BLX (a.k.a. BRANCH with link and exchange). But there is no interrupt_handler attribute for arm-g++ and I could not find any equivalent attribute. So I tried to resort to asm volatile and writing the asm code directly: template< class A1, class A2, class A3 > inline void __attribute__((always_inline)) JUMP3( void (*func)( A1, A2, A3), A1 a1, A2 a2, A3 a3 ) { asm volatile ( "mov.w r0, %1;" "mov.w r1, %2;" "mov.w r2, %3;" "b %0;" : : "r"(func), "r"(a1), "r"(a2), "r"(a3) : "r0", "r1", "r2" ); } So far, so good, in my theory, at least. Thumb-2 requires function arguments to be passed in the registers, i.e. r0..r2 in this case, so it should work. But then the linker dies with undefined reference to `r6' on the closing bracket of the asm statement ... and I don't know what to make of it. OK, I'm not the expert in C++, and the asm syntax is not very straightforward... so has anybody got a hint for me? A hint to the correct __attribute__ for arm-g++ would be one way, a hint to fix the asm code would be another. Another way maybe would be to tell the compiler that a1..a3 should already be in the registers r0..r2 when the asm statement is entered (I looked into that a bit, but did not find any hint).

    Read the article

  • What do you name the "other" kind of view-model in an MVVM project?

    - by DanM
    With MVVM, I think of a view-model as a class that provides all the data and commands that a view needs to bind to. But what happens when I have a database entity object, say a Customer, and I want to build a class that shapes or flattens the Customer class for use in a data grid. For example, maybe this special Customer object would have a property TotalOrders, which is actually calculated using a join with a collection of Order entities. My question is, what do I call this special Customer class? In other situations, I'd be tempted to call it a CustomerViewModel, but I feel like "overloading" the notion of a view-model like this would be confusing in an MVVM project. What would you suggest?

    Read the article

  • JQuery cycle plugin + PNG overlay + Image alt text as title conflict

    - by Dave
    I am trying to achive the following: Create an image gallery using the JQuery Cycle plugin that shows images with titles (taken from the alt text) Each image has a PNG absolutley posiioned over the top to achieve rounded corners effect Here's my gallery HTML: <div id="slideshow" class="pics"> <div class="photo-container" > <img src="/path/to/image" alt="alt text as title" /> <img class="mask" src="path/to/mask" /> </div> </div><!-- /slideshow --> <div id="title"></div> Here's my Jquery gallery function: $(function() { $('#slideshow').after('<div id="nav" class="nav"><span style="margin: 0 5px 0 30px;">next image</span>').cycle({ fx: 'fade', timeout: 0, cleartypeNoBg: true, pager: '#nav', next: '#slideshow', before: onBefore }); function onBefore() { $('#title').html(this.alt); } $('#nav a').after('<span>&gt;</span>') }); </script> Here is my CSS that handles the mask: .photo-container { position: relative; display: block; overflow:hidden; border: none; } img.mask { position: absolute; top: 0; left: 0; overflow:hidden; border: none; } The above does not output the alt text into the "title" div. When I remove the mask, it works: <div id="slideshow" class="pics"> <img src="/path/to/image" alt="alt text as title" /> </div><!-- /slideshow --> <div id="title"></div> Any ideas why the additonal div / image is casuing the title to not display? Thank you

    Read the article

  • Visual Studio 2008 having problems with namespaces when used as type in Generic coolection

    - by patrick
    I just upgraded last week from Visual Studio 2005 to 2008. I am having an issue with compiler resolving namespaces when I use a class as a type in a Generic collection. Intellisense recognizes the class and the compiler generates no errors when I use the class except when it is a type in a Generic collection declaration either as return type for a Property or as a parameter to a method. This is happening in my only project that is targeting the 3.5 framework, but changing the project containing the class to use the 3.5 framework doesn't fix the problem. Examples Compile fine MyClass myClass = new MyClass(); SortedList <DateTime,MyClass> listOfClasses = new SortedList<DateTime,MyClass> Compile error - Namespace could not be found public SortedList<DateTime,MyClass> ClassList { get; set; } private void DoSomethingToLists(SortedList<DateTime,MyClass> classList) Intellisense has no problem resolving the namespace, only the compiler. Is this a known bug or am I missing something obvious? Will SP1 fix it? I was able to create a new library containing just this class targeting 3.5 and am now able to successfully use this in both 3.5 and 2.0 projects. My guess is that even though I tried to change the target of my original library, since it was still referencing 2.0 projects there was some conflict.

    Read the article

  • C# Property inheritance question

    - by mcxiand
    Hi all, How do i inherit a property in c# from an interface and give that property other name on the class? For example: public interface IFoo { int Num {get;set;} } public class IFooCls : IFoo { int Ifoo.Num{get;set} } In this case, what the property name in the interface is also the same in the class. What i want is to give other property name on the class but still pointing to "Num" in the interface in this case. In VB, we can do it like this: Public ReadOnly Property UserId() As String Implements System.Security.Principal.IIdentity.Name Get Return _userId End Get End Property

    Read the article

  • ASP.NET MVC - Appending data onto a file download

    - by aschepis
    what is the best way to append data onto a file download? I figure that i can make my own class that implements InputStream and just consolidates two input streams (the file first, my additional data to append second.) but is there an existing view class that i can use to just return an InputStream or will i have to roll my own view class as well?

    Read the article

  • How to mock static member variables

    - by pkrish
    I have a class ClassToTest which has a dependency on ClassToMock. public class ClassToMock { private static final String MEMBER_1 = FileReader.readMemeber1(); protected void someMethod() { ... } } The unit test case for ClassToTest. public class ClassToTestTest { private ClassToMock _mock; @Before public void setUp() throws Exception { _mock = mock(ClassToMock.class) } } When mock is called in the setUp() method, FileReader.readMemeber1(); is executed. Is there a way to avoid this? I think one way is to initialize the MEMBER_1 inside a method. Any other alternatives? Thanks!

    Read the article

  • Purpose of singletons in programming

    - by thecoshman
    This is admittedly a rather loose question. My current understanding of singletons is that they are a class that you set up in such a way that only one instance is ever created. This sounds a lot like a static class to me. The main differnce being that with a static class you don't / can't instance it, you just use it such as Math.pi(). With a singletong class, you would still need to do something like singleton mySingleton = new singleton(); mysingleton.set_name("foo"); singleton otherSingleton = new singleton(); // correct me if i am wrong, but mysingleton == othersingleton right now, yes? // this the following should happen? otherSingleston.set_name("bar"); mysingleton.report_name(); // will output "bar" won't it? Please note, I am asking this language independently, more about the concept. So I am not so worried about actually how to coed such a class, but more why you would wan't to and what thing you would need to consider.

    Read the article

  • @Resource annotation is null at run-time.

    - by Andrew
    I'm using GlassFish v3. The following field is declared in a class: @Resource private javax.sql.DataSource _data_source; The following is declare in web.xml: <data-source <namejava:app/env/data</name <class-namecom.mysql.jdbc.Driver</class-name <server-namelocalhost</server-name <port-number3306</port-number <usermyUser</user <passwordmyPass</password </data-source At run-time _data_source is empty. What am I doing wrong?

    Read the article

  • allocator with no template

    - by Merni
    Every stl container take an allocator as a second object, template < class T, class Allocator = allocator<T> > class vector; If you write your own class It is possible to use your own allocator. But is it possible to write your own allocator without using templates? For example, writing this function is not easy if you are not allowed to use templates pointer allocate(size_type n, const_pointer = 0) { void* p = std::malloc(n * sizeof(T)); if (!p) throw std::bad_alloc(); return static_cast<pointer>(p); } Because how could you know the size of T?

    Read the article

  • Proper usage of Java Weak Reference in case of nested collections

    - by Tong Wang
    I need to define a weak reference Map, whose value is a Set. I use Google collections' MapMaker, like this: Map<Class<? extends Object>, Set<Foo>> map = new MapMaker().weakKeys().weakValues().makeMap(); So, for Set<Foo>, can I use a normal HashSet? Or, do I have to create a weak HashSet, like this: Collections.newSetFromMap(new WeakHashMap<Foo, Boolean>()); And why? Another question, the key of my map is Class objects, when will a Class object become weakly reachable? In other words, what is the lifetime of a Class object? Thanks.

    Read the article

< Previous Page | 415 416 417 418 419 420 421 422 423 424 425 426  | Next Page >