As the title say, I have some problem understanding what does this call return.
This is how I am using it:
fetchEngines()
{
let object = Ember.getOwner(this).lookup('application:main').engines;
console.log(object);
}
And it return me something like that:
At this point, this is what I want, the list of all my ember-engines.
But I don't know how to use it. By that I mean, how do I fetch the name of each engine, what is object at this point, I can't find anything about it.
I have tried the forEach() method, but it returns me : object.forEach is not a function. I have also tried the Object.keys method, but it returned me undefined, maybe somebody can indicate me a doc or something, I don't understand at all what is it.
Good day to you and thank you for reading.
I will answer this. This is very simple, and I made a mistake. The Object.keys method work, I didn't know how to write it well.
This is the corrected version:
fetchEngines()
{
let object = Ember.getOwner(this).lookup('application:main').engines;
// This will properly show every key in your object
console.log(Object.keys(object));
// And if you want to enumerate it
let filledArray = [];
for (let key in object) {
if (object.hasOwnProperty(key))
filledArray.push(key);
}
// The object filledArray is now a perfectly manipulable object
}
Related
I understand that this may be a duplicate of Any equivalent of Ruby's public_send method?. I'd like to explain what I am doing, and perhaps someone could advice.
I've been porting a ruby app over the last few days to learn Crystal. I've had to cut out a lot of functionality due to lack of send but today I've hit a main artery in my program.
I have a Hash which contains keystroke as key, and method as value. Based on what key is struck, the appropriate method is called. This obviously uses the send to implement the same.
From the linked question, I understand that Crystal is compiled so dynamic method calls are not permitted. However, if you look at the Vim editor, a user can map keys to methods, too. And vi(m) is written in C.
I am wondering if I missed something.
I know I could probably hardcode a switch statement with each key and call the appropriate method, but that still does not allow the user to assign a key to a method. Is there any alternative to this very large switch-case method ?
(I am guessing that rather than check the key in the when part, I would check the binding and call the method.
binding = #bindings[key]
case binding
when :up
up
when :down
down
when .....
else
end
Any better solution ?
I'm not sure that this way most simple and convenient (perhaps more experienced developers will correct me below) but i would use the Proc:
def method1
puts "i'm method1"
end
def method2
puts "i'm method2"
end
def method3
puts "i'm method3"
end
hash = {
"ctrl": -> { method1 },
"shift": -> { method2 },
"alt": -> { method3 }
}
binding = ["ctrl", "shift", "alt"].sample
hash[binding].call #=> i'm method2
See working example
We have a business need to collect specific bindings in every JSF page. and we do that inside overridden ViewHandlerWrapper class
I use the below code inside renderView method to get the whole expression value property for every RichInputText and it's work fine for me
ValueExpression valExp = Inputcomponent.getValueExpression("value");
String ExpressionString = valExp.getExpressionString();
output was: #{binding.EmployeeId.inputValue}
When I do the same against RichButtin I got null value as following:
ValueExpression valExp = Btncomponent.getValueExpression("actionlistener");
String ExpressionString = valExp.getExpressionString();
What is the wrong in my last peace of code?
Obtaining a ValueExpression form a RichInputText works because, as the name suggests, it evaluates to a value, which may or may not be an EL expression, let alone a method.
On the other hand, a RichButton does not really have to evaluate to something; rather, it aims to invoke behavior (i.e. a method), from which you would want a MethodExpression - though in this case, the closest we get to it is a MethodBinding.
Luckily, UIXCommand, a superclass of RichButton, provides two methods from which you can obtain your action listeners:
public final MethodBinding getActionListener()
From the MethodBinding returned, you can invoke getExpressionString() so you can get what you wanted - such as some actionListener EL string like #{binding.bean.actionListenerMethod}.
public final ActionListener[] getActionListeners()
Might be worth mentioning, though there is not much merit for this in your use case. It simply returns the listeners on which you can manually process the events.
I have an Optional list of integers. I wish to see if the list is actually present and then convert it into a stream. One way of doing this is
Optional<List<Integer>> listOfNumbers = ...
if (listOfNumbers.isPresent()) {
listOfNumbers.get().stream();
}
But, I dont wish to have that if condition. I searched and saw that ifPresent() does the same thing but when I do listOfNumbers.ifPresent(this::get)), I get the following error:
non-static variable this cannot be referenced from a static context
Can you please help me do this in an efficient manner? This is still new to me so if there's anything incorrect in my understanding please let me know.
As pointed in the comments, the cleanest way to get a Stream is to use Optional.orElse method with Collections.emptyList:
Stream<Integer> stream = listOfNumbers.orElse(Collections.emptyList()).stream();
The other possible solution with Optional.map:
Stream<Integer> stream = listOfNumbers.map(List::stream).orElse(Stream.empty());
Update Java 9 :
Since jdk9, Optional has a new method stream(), which returns either a stream of one element, or an empty stream.
Thus, going from an Optional<List<Integer>> to an Stream<Integer> becomes
Stream<Integer> streamOfNumbers = listOfNumbers.stream().flatMap(List::stream);
This is How I did that on my last Project.
Optional<List<Integer>> listOfNumbers = ...
listOfNumbers.ifPresent((numbers) -> {
...
});
The ifPresent will check if the size of your Optional variable reaches it's limit and loop through your list.
You can replace ifPresent with forEach if you want to do it separately instead.
I was trying to answer this question: emberjs: add routes after app initialize()
I started to play with Ember.Object.reopen(), to understand how it works, and perhaps finding a way of answering the previous question.
I feel a bit puzzled, and don't understand the behavior of this code:
jsfiddle: http://jsfiddle.net/Sly7/FpJwT/
<script type="text/x-handlebars">
<div>{{App.myObj.value}}</div>
<div>{{App.myObj2.value}}</div>
<div>{{App.myObj3.value}}</div>
</script>
App = Em.Application.create({});
App.MyObject = Em.Object.extend({value: 'initial'});
App.set('myObj', App.MyObject.create());
Em.run.later(function(){
App.get('myObj').reopen({
value: "reopenOnInstance"
}); // the template is not updated, 'initial' is still diplayed, but
console.log(App.get('myObj').get('value')); // print 'reopenOnInstance'
App.MyObject.reopen({
value: "reopenOnClass"
});
App.set('myObj2',App.MyObject.create()); // the template is updated and
console.log(App.get('myObj2').get('value')); //print 'reopenOnClass'
App.myObj3 = App.MyObject.create(); // the template is not updated but
console.log(App.myObj3.get('value')); // print 'reopenOnClass'
Em.run.later(function(){
App.get('myObj').set('value', "setWithSetter"); // the template is updated and
console.log(App.get('myObj').get('value')); // print 'setWithSetter'
App.get('myObj2').set('value', "setWithSetter"); // the template is updated and
console.log(App.get('myObj2').get('value')); // print 'setWithSetter'
App.myObj3.set('value', "setWithSetter"); // the template is not updated but
console.log(App.myObj3.get('value')); // print 'setWithSetter'
}, 2000);
},2000);
If someone can explain what is going on, particularly why the templates are sometimes not updated, sometimes updated, and also what's the difference between calling reopen on a class, calling it and on a instance.
Not 100% sure, but I will try and answer you questions.
First lets look at "myObj3". The ember getter/setter methods trigger the updates in the templates (they fire internal events which cause every property/observer to know something happened). Just setting a value by hand does update the value but will not fire these events and hence nothing changes in the UI. Kind of like when you use a Mutable list you use pushObject to make sure the UI updates.
Now lets look at your "reopen". When you reopen on the class it works as you would expect and updates the base class. When you reopen an instance it is actually creating a mixin and shims it on top of the object. This means when you do a "get" ember iterates over the mixin & object for the value to return. It finds that mixin and gets the value before the object; you could actually replace the method with a "return 'foo '+this._super()" on the instance you will get 'foo initial' (think of your object has having layers like an onion). If you have a group of mixin on top of your object you will have a hard time finding the correct value if you set something directly (but "get" will work perfectly). This leads to the general rule that you should always use "set" instead of a direct reference.
Side note: You can call "getPath" instead of "get" and you can use the relative or absolute path. Such as App.getPath('myObj2.value') which will make the code a little easier to manage. Goes for "setPath" also.
Lastly: The last value prints because you did change the value (it is in there) but the trigger for ember to update the ui never fired because you never called set on "myObj3" object.
EDIT: In the lastest version of ember it looks like the reopen on an instance does do a merge-down on the object (if that key already exists). The mixin only will wrap if you are adding new content.
I'm using the Chromium port of WebKit on Windows and I'm trying to retrieve a list of all of the images in my document. I figured the best way to do this was to implement WebKit::WebFrameClient::didFinishLoading like so:
WebNodeList list = document->getElementsByTagName(L"img");
for (size_t i = 0; i < list.length(); ++i) {
// Manipulate images here...
}
However, when this delegate fires, list.length() returns 0. The only times I've seen it return a list of non-zero length is when I substitute "body" or "head" for "img". Strangely enough, if I call getElementsByTagName(L"img") outside of the delegate, it works correctly.
I'm guessing that the DOM isn't fully loaded when didFinishLoading is called, but that would seem to contradict the delegate's name. Does anyone know what I may be missing here?
It turns out that the mistake was purely on my side. I was caching a pointer to the DOM document in my frame wrapper. Of course, since a frame can outlive a DOM document, I ended up referencing an out-of-date document once I loaded a new page.