i'm new here and i hope my question is not too trivial.
I have a package with a static class in it (a Grid Builder) and want to use it in symfony2
So i know about the Class loading and the Service Container but i don't get the Container to work.
The Grid Class is depending on 2 other static classes (one for configuration and one for the SQL Query´s)
The Code to use the class is as following:
$Grid = Grid::get_instance();
$Grid->table('products');
echo $Grid->renderGrid();
And internally the class uses calls like GridConfig::database() - so i Thought maybe i cann simply add all three classes to the Service.yml but that doesn't do anything.
So my question is: How can I inject the Static class in a way that I can use it in the Controller?
Is it Possible and if yes what would be the best Practice case to do it?
Thank you for any help.
Since it is static then there really is no need to inject it. Something like:
$grid = \Grid::get_instance;
Should work. If Grid uses namespaces then you need to add that as well. And you will need to ensure the autoloader can find it.
Of course using globals is kind of frowned up. What you can do is to write your own service to act as a wrapper.
class MyGridService
{
protected $grid;
public function getInstance()
{
if (!$this->grid) $this->grid = \Grid::get_instance();
return $this->grid;
}
}
Add MyGridService to your services.yml file then from the controller you can do:
$grid = $this->get('my_grid_service')->getInstance();
You should define a service that uses a factory method to instantiate the object:
service_name:
class: The\Class\Name\Of\The\Created\Object
factory: [ "Grid", "get_instance" ]
Now you can inject the object into your depending class by injecting the service.
See http://symfony.com/doc/current/components/dependency_injection/factories.html
Related
Background: symfony3
I have just stuck in the fact that redirectToRoute and addFlash methods in controller are protected in symfony. I have a separate class for action.
namespace AppBundle\Action;
class Base {
public function __construct($controller) {
$this->controller = $controller;
}
}
As you can see base action class requires a controller. Basically it is logical because action class is part of a controller and should have access to all its methods. However I cannot call $this->controller->addFlash as it is protected. If it is protected then there might be some reason for it. I cannot find it. Can you please hint me how I can change my action class so that it could use controller methods.
The variant about extending action from a controller does not fit me as I have additional functionality in the main controller. It is configured in a proper way.
Update: my goal is to devide controller functionality by responsibility. I invented an action class. My end code look like following:
public function editAction() {
$instance = new \AppBundle\Action\MyController\Edit($this);
return $insance->run();
}
In this case I keep controller clean and not verbose.
Here is a link to Symfony Controller Trait, that you can duplicate, if you really want to work that way.
But since you are injecting a whole symfony controller into your own controllers, you will be better off with extending instead. Injection is used here for injecting separate service by their IDs.
I have a big set of classes (like more that 100) and they are all extend from some abstract class, let's call it ParentClass. Let's call child classes ChildA,ChildB, etc. How can I register custom deserializer for all children and get class type inside my Deserializer?
I tried:
module.addDeserializer(ParentClass.class, new MyObjectDeserializer());
but it does not work.
I want to skip doing (what is working):
module.addDeserializer(ChildA.class, new MyObjectDeserializer(ChildA.class));
module.addDeserializer(ChildB.class, new MyObjectDeserializer(ChildB.class));
module.addDeserializer(ChildC.class, new MyObjectDeserializer(ChildC.class));
//etc......
Class type should be known, as I am use Jackson for spring #RequestBody method, what have defined class name there.
Any ideas how this can be done?
As far as I know, I don't think there is a mechanism in jackson that will address your exact needs.
However, there are a couple alternatives you can try.
Deserializing polymorphic types with Jackson describes one such alternative, however, you would still need to explicitly define all of the supported subtypes.
Another alternative that would not require you to explicitly define deserialization relationships would be to change your class hierarchy from one of inheritance to that of a container.
For example, converting your abstract parent class to a container like so:
public class DataContainer<T> {
String commonString;
Integer commonInteger;
T subData;
}
Would allow you to simply define in your controller input function as
public String controllerFunction(DataContainer<ClassA> classA);
without a need to define all these subclass deserializations.
Late to the party but I had a similar problem which I solved by registering a custom Deserializers to my SimpleModule. The code is in Kotlin but it should be easy to port it to Java.
The class itself:
class UseBaseClassSimpleDeserializers(
private val baseClass: Class<*>,
private val baseClassDeserializer: JsonDeserializer<*>
) : SimpleDeserializers() {
#Throws(JsonMappingException::class)
override fun findBeanDeserializer(
type: JavaType?,
config: DeserializationConfig?,
beanDesc: BeanDescription?
): JsonDeserializer<*>? {
val beanDeserializer = super.findBeanDeserializer(type, config, beanDesc)
return if (beanDeserializer == null && baseClass.isAssignableFrom(type!!.rawClass)) {
baseClassDeserializer
} else {
beanDeserializer
}
}
}
How to register the custom Deserializers class to a SimpleModule:
val simpleModule = SimpleModule()
simpleModule.setDeserializers(UseBaseClassSimpleDeserializers(ParentClass::class.java, ParentClassDeserializer()))
I have a service in Symfony2 that looks like:
services:
MyCustomService:
class: MyClass
arguments: //Arguments aren't static, but dynamic based on application logic.
Is it possible to pass dynamic variables to a service's constructor?
There doesn't seem to be any extra parameters within a controller's $this->get('MyCustomService');
Is there something I'm missing?
To me, it sounds like, you do not understand what a word "service" really means. What you are trying to achieve, would not be a service anymore.
You can still define a setter method inside your "MyClass" for any custom arguments, while defining some default ones, which you basically override when you use setter method.
You would use something like this:
$this->get('MyCustomService')->setSomething($something);
If, for whatever reason, you are unable to configure the service after instantiation (i.e., with a configurator). What about delegating that responsibility to a factory? It will let you instantiate services with "dynamic arguments".
services:
MyCustomServiceFactory:
class: MyClassFactory
arguments: [ #dynamicService, %time_prefix% ]
MyCustomService:
class: MyClass
factory_service: MyCustomServiceFactory
factory_method: get
Your factory would like something like this:
class MyClassFactory
{
private $dynamicService;
private $timePrefix;
public function __construct(MyDynamicService $dynamicService, $timePrefix)
{
$this->dynamicService = $dynamicService;
$this->timePrefix = $timePrefix;
}
public function get()
{
// Dynamic arguments based on application logic.
$dynamicArg1 = $this->dynamicService->getArg()
$dynamicArg2 = $this->timePrefix . time();
return new MyClass($dynamicArg1, $dynamicArg2);
}
}
I've got an object declared and instantiated in my Flex application's singular MXML file:
public var CDN:CDNClass = new CDNClass;
I would like to access this same CDN object (and its public methods and properties) in another class declared in a separate .as file as such:
package my.vp
{
import my.media.CDNClass;
public class SyncConnectorManager
{
private function syncMessageReceived(p_evt:SyncSwfEvent):void
{
switch (p_evt.data.msgNm)
{
case "startStream" :
// Play a stream
CDN.parsePlayList(p_evt.data.msgVal);
break;
But when I try to access the public method parsePlayList in the CDN object in a method in the class defined in the .as file, I get the following error:
Access of undefined property CDN
The reason I want to do this is to break up the logic of my application into multiple AS files and have minimal MXML files, probably only one.
Thanks - any help is much appreciated. Perhaps my OOD/OOP thinking is not correct here?
IT depends on your class architecture. For your code to work, the CDNClass instance must be defined and implemented inside your SyncConnectorManager.
Generally, you can always call down into components, but should never call up
One option is to pass the instance ofCDNClass to a variable inside SyncConnectorManager. Add this variable to your SyncConnectionManager class:
public var CDN:CDNClass = new CDNClass;
And at some point do this:
syncConnectorManagerInstance.CDN = CDN;
That way both classes will have access to the same CDN instance and can call methods on it.
Yes, your OOP thinking is not correct here. You should take in mind differences between classes and instances. This line declares a filed in a current class and initiates it with an instance:
public var CDN:CDNClass = new CDNClass;
So current instance of your MXML class (you can think about it as usual AS class with some other notation) has public field. To operate with CDN instance you need something from the following:
Read the value of CDN (as far as it is public) from the instance of your MXML class. You need some reference to it for that.
The instance of your MXML class can have a reference to the instance of SyncConnectorManager and SyncConnectorManager should have a way to inject the value of CDN there. Something like:
Your class:
package my.vp
{
import my.media.CDNClass;
public class SyncConnectorManager
{
private var CDN:CDNClass;
public function SyncConnectorManager(CDN:CDNClass)
{
this.CDN = CDN;
}
private function syncMessageReceived(p_evt:SyncSwfEvent):void
{
switch (p_evt.data.msgNm)
{
case "startStream" :
// Play a stream
CDN.parsePlayList(p_evt.data.msgVal);
break;
In your case SyncConnectorManager class hasn't CDN declared (the problem of the compiler error you mentioned) and instantiated (the problem of NPE even if you just declare field).
As the bottom line I can suggest you to follow ActionScript naming and coding conventions to talk other people and team members about your code :)
I have a doubt,.... How would you create a Singleton class in Flex...
Is there any convention like the class name should eb Singleton or it should extend any other class.
How many Singleton class can a project have?
Can anyone say the real time usage of a Singleton class?
I am planning to keep my components label texts in a Singleton class... Is it a good approach.
Can of worms asking about singletons!
There are a few different options about creating singletons mainly due to AS3 not having private constructors. Here's the pattern we use.
package com.foo.bar {
public class Blah {
private static var instance : Blah;
public function Blah( enforcer : SingletonEnforcer ) {}
public static function getInstance() : Blah {
if (!instance) {
instance = new Blah( new SingletonEnforcer() );
}
return instance;
}
...
}
}
class SingletonEnforcer{}
Note that the SingletonEnforcer class is internal so can only be used by the Blah class (effectively). No-one can directly instantiate the class, they have to go through the getInstance() function.
hope I'm not hitting dead horses here :)
(edit: ahh, I'm just repeating phils link)
Gregors singleton implementation does not protect against invoking the constructor with a null value, as in:
var b:Blah = new Blah(null);
You will still have only 1 instance, but invoking the constructor is still possible with the consequences that follows.
If you absolutely must enforce the singleton, the constructor should make sure that the enforcer parameter isn't null.
public function Blah( enforcer : SingletonEnforcer ) {
if(!enforcer){
throw new Error("whoops!");
}
}
You should also be concerned about ApplicationDomain when loading swf files. External swf files that uses the same definitions, may have multiple singleton instances (1 in each separate applicationdomain) if you do not specify that the swf file must be loaded into the existing applicationdomain.
This means that Blah.getInstance() in AAA.swf is not the same instance as Blah.getinstance() in BBB.swf, if AAA.swf loads BBB.swf without a LoaderContext instance that tells the plugin to load BBB.swf into the same ApplicationDomain as AAA.swf
First you can reference a previous question to find out how to create a singleton class. You can find more info from a Yakov Fain presentation as well.
Second question, your project can technology have as may singleton class as you see fit but it will only create 1 instance of each. For example, in the cairngorm architecture you have 3 main singletons: controller, service and model. The number of actual class can very depending on your project.
Finally, A real world solutions would be. You have 2 components that need to talk to each other but you don't want them to know the other exists. Meaning sometimes the components are there and sometimes they are not...so you need them to be loosely coupled. you can uses singletons to pass the data from one component to the other with out "talking" to them directly.
Using singletons is a good approach if you need to pass data around your application from component to component and would like to decouple them from each other.
package com.foo.bar
{
public class MySingleton
{
private static var _instance:MySingleton = new MySingleton;
private var _myName:String;
public static function get instance():MySingleton
{
return _instance;
}
public function set myName(value:String):void
{
_myName = value;
}
public function get myName():String
{
return _myName;
}
}
}
Notice the absence of a constructor here.
Hello you could check out the following of a Flex Singleton Class example on http://www.how-to-code.com/flex/flex-design-patterns/flex-singleton-class.html