I have a WinJS class defined as follows and would like to use a member function in the constructor:
WinJS.Class.define(
function() {
setInterval(myMemberFunction, 100);
},
{ // Member variables
myMemberFunction: function() {
// Do something
}
});
Unfortunately it looks like I can't resolve member functions in that manner in the constructor. This code all lives in a module so I could move myMemberFunction up the hierarchy and access it from the constructor, however the drawback is that "this" would no longer refer to the instance of my WinJS class. What's the recommended method for accessing instance members in a WinJS from the constructor?
Generally speaking, you refer to any method or property using "this," as in this.myProperty. In the case of event handlers, you need to make sure that the "this" that you see inside the handler is the instance "this". That's the purpose of the bind method of a function object. So you do this:
setInterval(this.myMemberFunction.bind(this), 100);
This makes sure that you bind the right "this" instance to the callback. Because I've seen this question pop up frequently (use of .bind is all over the Windows SDK samples), I wrote about this in more detail on http://www.kraigbrockschmidt.com/2012/11/28/purpose-function-dot-bind/.
Just to note, this is pure JavaScript; nothing particular to WinJS or Windows Store apps.
Related
I have a class:
class Hello {
function doSomething(&$reference, $normalParameter) {
// do stuff...
}
}
Then I have a controller:
class myController {
function goNowAction() {
$hello = new Hello();
$var = new stdClass();
$var2 = new stdClass();
$bla = $hello->doSomething($var, $var2);
}
}
The "goNow" action I call using my tests like so:
$this->dispatch('/my/go-now');
I want to mock the "doSomething" method so it returns the word "GONOW!" as the result. How do I do that?
I've tried creating a mock
$mock = $this->getMock('Hello ', array('doSomething'));
And then adding the return:
$stub->expects($this->any())
->method('discoverRoute2')
->will($this->returnValue("GONOW!"));
But I'm stumped as to how to hook this up to the actual controller that I'm testing. What do I have to do to get it to actually call the mocked method?
You could create a mock for the reference, or if it is just a simple reference as your code shows, send a variable. Then the normal mock call may be called and tested.
$ReferenceVariable= 'empty';
$mock = $this->getMock('Hello ', array('doSomething'));
$stub->expects($this->any())
->method('discoverRoute2')
->will($this->returnValue("GONOW!"));
$this->assertEquals('GONOW!', $stub->doSomething($ReferenceVariable, 'TextParameter'));
Your example code does not explain your problem properly.
Your method allows two parameters, the first being passed as a reference. But you create two objects for the two parameters. Objects are ALWAYS passed as a reference, no matter what the declaration of the function says.
I would suggest not to declare a parameter to be passed as a reference unless there is a valid reason to do so. If you expect a parameter to be a certain object, add a typehint. If it must not be an object, try to avoid passing it as a reference variable (this will lead to confusing anyways, especially if you explicitly pass an object as a reference because everybody will try to figure out why you did it).
But your real question is this:
But I'm stumped as to how to hook this up to the actual controller that I'm testing. What do I have to do to get it to actually call the mocked method?
And the answer is: Don't create the object directly in the controller with new Hello. You have to pass the object that should get used into that controller. And this object is either the real thing, or the mock object in the test.
The way to achieve this is called "dependency injection" or "inversion of control". Explanaitions of what this means should be found with any search engine.
In short: Pass the object to be used into another object instead of creating it inside. You could use the constructor to accept the object as a parameter, or the method could allow for one additional parameter itself. You could also write a setter function that (optionally) gets called and replaces the usual default object with the new instance.
There is this $entry method that we can use in GWT to allow external javascript to execute java methods.
You can see the explanations in their documentation https://developers.google.com/web-toolkit/doc/latest/DevGuideCodingBasicsJSNI?hl=fr#calling
However, the example there is only with static methods. I'm trying to write it for a non-static method and when I try to call it, I get an exception :
java.lang.ClassCastException: Cannot cast com.google.gwt.core.client.JavaScriptObject$ to mypackage.MyModule
Here is my code :
public native void setRefreshModuleCallback() /*-{
$wnd.refreshModule = $entry(function() {
this.#mypackage.MyModule::refreshModuleJava();
alert('test');
});
}-*/;
public void refreshModuleJava() {
logger.log(Level.WARNING, "REFRESH");
}
What I find very funny is that alert is called, I see the result in the browser, but the call just before is not performed.
Do you know if it's actually possible to do such thing ?
$entry is not about calling java, it's about ensuring a few things go well in GWT: exceptions are routed to the GWT.UncaughtExceptionHandler, and commands scheduled via Scheduler#scheduleEntry and Scheduler#scheduleFinally are correctly called.
Your problem is the this. When the function is called, this is not your MyModule class (it's most probably the $wnd object). This is why the question you linked to uses var that = this. It's about scoping.
You also need to actually call the method, not only reference it: in JSNI, the first pair of parens are for the formal parameters (to disambiguate overloads), and you need another pair passing the actual arguments: that.#mypackage.MyModule::refreshModuleJava()().
I've seen this question regarding partial stubs, but it does not quite tell me what I need to know.
I understand that, if I am using a Moles stub for a class (let's say, for DataService, I'm using SDataService), I can set the CallBase property to true so that, if there is no delegate for a particular method, the base implementation's method will be called. Great, but how do I assign a delegate to a particular method in this case?
If there is no way to do that, say I have an interface IDataService that I stub using SIDataService. I can easily assign a delegate to a method here. But, how do I tell it to call the corresponding method on DataService (an implementation of IDataService) if there is no delegate for a given method?
Thank you!
Edit:
I see now that the method needs to be virtual to be overridden in the first scenario above. I don't think that makes a whole lot of sense, but it is what it is.
So, focusing on the second scenario, would I have to create a Behavior? (And why isn't there one already for stubs like there is for moles?) Or is there a simpler way?
Delegates (detours) are set to stubs types the same way as mole types. For example, SIDataService.GetMemberProfile() is configured to return a mock object like this:
var memberMock = new Member() { Firstname="Joe", LastName="Schmoe" };
var stub = new SIDataService();
stub.GetMemberProfileMember = i => memberMock;
I've been reading up a bit about coffeescript's inheritance model and I have the feeling I'm on the fringes of an ideological debate which I really don't understand. So, I would be perfectly happy to find out that I'm just doing things in the wrong way.
Basically what I am doing is writing a set of widgets which, among other things, need to handle events on their DOM elements. I thought a good way to go about this would be to have a class method which would be called once, to delegate all the events which the widget might need. The base widget class might have some simple click handlers, while the subclass might add to that some mouseover handlers or extra click handlers.
However, it appears that I'm not supposed to try and do the equivalent of calling super() inside a static method. There is a workaround which exists, (this.__super__.constructor.METHODNAME() but I've seen a lot of suggestions that this isn't the best way to do what I'm trying to do. Has anyone got any insights on how I should structure this code? Keep using the workaround, or put all the delegation into a totally different place? I can't really just stick it in the prototype, since I won't necessarily have an instance to call the method on (or can I essentially still call a method on the prototype from a static context, like putting SwatchableWidget.prototype.delegateEvents() into an onload function or something?
Here's a bit of code to illustrate what I'm talking about:
class Widget
#testProp: "ThemeWidget"
#delegateEvents: ->
console.log "delegate some generic events"
class SwatchableWidget extends Widget
#testProp2 = "SwatchWidget"
#delegateEvents: ->
console.log "delegate some specific swatchable widget events"
this.__super__.constructor.delegateEvents()
Widget.delegateEvents()
SwatchableWidget.delegateEvents()
Thanks for any help.
I suggest replacing
this.__super__.constructor.delegateEvents()
with
Widget.delegateEvents()
trying to use super to call static methods is not required (and doesn't make much sense)
I don't understand why delegateEvents would be a class-level method, or why Widget.delegateEvents have to be called again from SwatchableWidget.delegateEvents. If it's just class initialization code, you should put it in the class body directly:
class Widget
console.log "delegate some generic events"
...
#testProp: "ThemeWidget"
class SwatchableWidget extends Widget
console.log "delegate some specific swatchable widget events"
...
#testProp2 = "SwatchWidget"
I take it you're waiting for a specific DOM state before running this initialization code? Maybe I could suggest another approach if you told me a little bit more about the preconditions for delegateEvents.
It sounds like you want a different type of inheritance model where each inherited function of a certain type ("parent calling") will walk the inheritance tree and call all its parents with the same name.
You could call any direct parent functions in each child manually as you've written. Then it will float up the inheritance chain anywhere you specify such a relationship.
I would bind the parents delegate call in the constructor to a current class function
delegateparents =>
#call any parent class methods
I couldn't find any reference on how to use a parent form element in a subclassed form. May be because it's obvious to everyone but me. It's got me stumped. This is what I tried.
At first, within my form constructor I called
parent::__construct($options = null);
then accessed the parent elements like this
$type = parent::setName($this->type);
The problem was that ALL the parent form elements would display whether explicitly called or not. Someone said, "don't use __construct(), use the init() function instead. So I changed the constructor to init(), commented out the parent constructor, then ran the form. It bombed saying it couldn't pass an empty value for setName(). I commented out all the seName() calls and the form ran, but only displayed the elements instantiated in the subclassed form.
My question is this: If I don't use the parent constructor, how do i get and use the parent's form elements?
Solved: Since the constructor was switched to init, the call to the parent also needed to be switched. Easy for someone with php background. Not so much for one who doesn't.
Use
parent::init();
Solved: Since the constructor was switched to init, the call to the parent also needed to be switched. Easy for someone with php background. Not so much for one who doesn't.
Use
parent::init();
You should learn OOP principles first. Obviously you have no understanding of it whatsoever. You need to call parent::init() in you Form_Class::init() method as you wrote, but why? Because otherwise the parent method is not called and is overriden by the From_Class method.
Other thing is that when you have a parent class "SuperForm" with input and submit, then your "SuperForm_Subclass" would have the same elements assigned. There is no need to use "parent::*" to access element (only exception would be if you used static SuperForm variable to store them - which makes no sense).
You can easily use $this->inputElement and $this->submitElement inside your SuperForm_Subclass like you would in the SuperForm class.
In your example you could used the __contruct() as good, but with the same condition of calling the parent constructor. You would be able to access elements generated there too...