However I'm not sure if this is legal in the sense of OOP design. Yes, Im learning that PHP cannot do some of the things Java can do when it comes to OOP programming, which is why Ive watched a bunch of his webinars mostly for OOP concepts. Where do you think i should go from here, learn more about factories? Is the above code he posted PHP? When using a factory container, do I load the actual class files within that container or outside the container from the main, calling script?
He notes that PHP doesnt have the ability to have more than one constructor per class and that you can achieve something similar by passing an array of parameters upon instantiation that your constructor then acts on to create the object. Perhaps Im missing something about how this is works in Sublime Text. Its times like this I want to give up on OOP (again) and jump back to familiar procedural coding so I can just get the work done. But these classes only need to be instantiated or initialized once, but accessible to all classes or objects that need them. My gosh, I have so much to learn. Thanks again for your input and help with this! Its unrealistic for web pages that need to load in 1 or 2 seconds. To use this object you just write the following: Now I DO implore you to use dependency injection where you can and aim for loosely coupled objects, but sometimes that is just not reasonable and the singleton pattern can be of use. Potentially also security is an issue. Yes, DI and then factories and just start using them. Pingback: Exakat Blog: 5 usages of static keyword in PHP - webdev.am, Exakat Blog: 5 usages of static keyword in PHP - webdev.am. bash loop to replace middle of string after a certain character. And those deeper layers (classes) of your application do not instantiate required objects but require them via DI. The getInstance()method uses a method know as lazy instantiation to delay creating the object to the last possible moment as you do not want to have unused objects lying around in memory never intended to be used. The one exception I make is Smarty for templates. Since static methods do not depends on an object, they are great for factories. So please excuse any dumb, newbie questions. But you will see how the big guys structure PHP applications and you will build your own opinions. I also found the above article on that same website, but its WAY over my head. How to encourage melee combat when ranged is a stronger option. There are strong opinions about whether the singleton pattern should or should not be used, but it does have its uses. But is it always like that? This allows for an instantiated class, or public static method to access it's own private/protected static methods. PHP parse/syntax errors; and how to solve them. Im thinking of taking this one step further by using a Params object that would hold all the parameters for an object, including dependencies, and a few basic methods for getting and setting those parameters.
Going further, the object type hints in the parameters dont have to be specific classes - they can be interfaces, which means PHP will accept any class that implements that interface. Because for some objects Ill have 4-6 dependencies in addition to a few parameters, and want the ability to instantiate the object with all of that in place.
Like in this topic, when using static methods we dont have to instantiate objects so naturally we dont have a problem with that. table below shows the Phake methods that have a separate counterpart for interacting with static calls. Ah, I completely overlooked that behaviour. So even with a theoretically the best possible solution to arbitrary parameters order the final benefit remains pretty minor. But yes, I might have chosen a too extreme caching method, I would go for the private property method by default unless I had a real need for a much more global static caching. I like what he has to say, too. This doesn't produce the result you want: That's because self refers to the Car class whenever method brand() is called. Can we access the instance variables from a static method in Java? // properties, properties, static methods and methods. In fact, PHP emits a fatal error, whenever the $this variable is directly mentioned in a static method : this is why the example has to use the variable variable to actually show the status. They are called (drumroll): static classes. It is not a map of objects but for the most part a clever mechanism that will infer the dependencies from the constructor parameters and create the objects, for example this same class as earlier: The container by using reflection knows that the necessary dependencies are BlogModel and TemplateEngine and can therefore create them automatically. He suggests to have one method for instantiating each object. I have some times heard developers debating on which one is better but I think they are most powerful when used in combination. In the example, it is the x class. Passing needed objects around (as dependencies) is really a small price to pay for long-term ease of maintenance. Static is short-term while dynamic is long-term. Lets review all the five of them : The most common usage of static is for defining static methods. Im now intrigued and will try to figure out how they work and what theyre for in this context.
2021 Copyrights. Okay, Ive used that but never in a return, and I didnt know about the ?
As you can see in the example code we are defining a private static property $instance to hold the object reference. There may be many shortcomings, please advise. I am in agreement with you on this 100%. Yes, Im using Sublime Text 3. Together, they handle the Late Static Bindings. Note that static methods may be called from an object, though the pseudo-variable $this will still NOT be available. I'm worried PHP may "patch" this in future versions if this is not a valid and break my scripts.
Lets create a class and initialize four variables. current class. Because you have more control over the input and validation of those parameters and also even though more verbose it is a lot more clear what the code is doing and what is expected to happen. Thanks so much for the detailed explanation, and the Factory example. Sure, some of the solutions you wont like or will seem not useful whereas you will like others. Most of the time, these utils are PHP static classes : According to a significant part of the PHP world, it might be the same thing.
Also, I presume what Db($this->getConfig()) is doing is passing in a dependency to the Db class during instantiation, is that right? DelftStack articles are written by software geeks like you. So, there is a use for static properties after all! Connect and share knowledge within a single location that is structured and easy to search.
I know this doesnt make clear what options the function needs, but I put all that in the comment block for the function, so its easy to figure out. I can achieve caching without static variables: You asked about Config returning a new instance each time so I changed it to return the same instance each time - you see, if you have a centralized place like a Factory (or DIC) to instantiate your objects its easy to change instantiation logic because it is done in one place so there is just a small piece of code to adjust. Theoretically, if you do it right then you can move the deeper layer from one framework to another and it will work because it requires all dependencies via DI and does not communicate in any other way with the outside world, the only requirement is that whatever code calls your classes provides the required dependencies. I find it easier to remember the parameter name rather than the order of each parameter. You can do it manually in the dirty way, or you can use your Factory, or you can use a DIC. Why is that property static? I can't find any real info stating it's ok to do this. Yes, I know, every time Ive mentioned this method of passing parameters to functions on a coding site no one ever seems to like it. I think the most logical place for that is just before calling new Object because this way you load only required files on demand. Instantiating all application objects every time may quickly eat your server resources, especially if you need to serve tens or hundreds requests per second. Then we start using OO with DI, which helps a lot with the code readability but then we come up with a problem of object instantiation. It is almost universally used, though there are many variations of it. But it doesnt show me all options for my custom functions as I type it out, it only does that for PHP built-in functions. Question: When using a factory container, do I load the actual class files within that container or outside the container from the main, calling script? Maintain statistics about your database tables using Laravel and triggers, Why you cant have a solid application using laravel, Clear old elements on Redis Cache with Laravel. And the static variable is local to one method only. Since this is static this reference is shared across ALL objects of this type. This allows you for quite a bit of flexibility. Why can't static method be abstract in Java? I guess I am mostly using composition, because Im not completely sure how inheritance is implemented in PHP. Is there a PRNG that visits every number exactly once, in a non-trivial bitspace, without repetition, without large memory usage, before it cycles? Static methods would be namespaced functions. cannot verify or stub all static calls. If there are too many dependencies it may be a sign that the class has too many responsibilities and its a good idea to break it into several components. Closure are functions that may be stored in a variable : functions may have their name stored in a variable, though. thanks a lot. I thought static properties and methods should be avoided. A common example is the database connection - the code that runs the main part of the application (like a router) will not do any operations straight on the database but will execute a method that does a certain task and that method will use the database as a dependency. But if I had factories, Id basically have to do the same thing, altering the factories for each class so that they recognize and inject the new dependency. Note that the variable is completely invisible from the outside world, just like a private property. Sorry I thought by saying "have code you possibly don't want to be public" was referred to the possibility of override/inherit it. But you dont have to go that far now, you can use a simple factory like this: And you instantiate one Factory object at the top of your application and then use that one instance to create your objects and execute whatever is needed for your application: and you have a very simple application based on dependency injection with no static methods! That video also mentions interfaces, and Ive read about them but didnt really understand what they are for so havent used them yet. To subscribe to this RSS feed, copy and paste this URL into your RSS reader. I tried making my own template rendering code, became too complicated and messy. If you have crazy amounts of data, its probably a bad idea to use static.
Static properties have several niche usages. Why are static properties and methods available in OOP if they should be avoided? For me, its just overkill. The first of them is being a property for a static method. When using static classes you have to use global variables as well and the biggest problem are hidden dependencies. If you are Binding: http://www.php.net/manual/en/language.oop5.late-static-bindings.php. We will initialize a method called simpleProfile(). People use this technique to store the results of previous expensive operations to optimize their script. As a general rule, its best to give everything the lowest visibility possible. This allows for an instantiated class, or public static method to access it's own private/protected static methods. I would love to have your opinion on this. Optional dependencies can be required via optional parameters in the constructor or be supplied using setter injection. The other article you linked to mentions Factories that can be used to instantiate an object with its dependencies.
He notes that PHP doesnt have the ability to have more than one constructor per class and that you can achieve something similar by passing an array of parameters upon instantiation that your constructor then acts on to create the object. Perhaps Im missing something about how this is works in Sublime Text. Its times like this I want to give up on OOP (again) and jump back to familiar procedural coding so I can just get the work done. But these classes only need to be instantiated or initialized once, but accessible to all classes or objects that need them. My gosh, I have so much to learn. Thanks again for your input and help with this! Its unrealistic for web pages that need to load in 1 or 2 seconds. To use this object you just write the following: Now I DO implore you to use dependency injection where you can and aim for loosely coupled objects, but sometimes that is just not reasonable and the singleton pattern can be of use. Potentially also security is an issue. Yes, DI and then factories and just start using them. Pingback: Exakat Blog: 5 usages of static keyword in PHP - webdev.am, Exakat Blog: 5 usages of static keyword in PHP - webdev.am. bash loop to replace middle of string after a certain character. And those deeper layers (classes) of your application do not instantiate required objects but require them via DI. The getInstance()method uses a method know as lazy instantiation to delay creating the object to the last possible moment as you do not want to have unused objects lying around in memory never intended to be used. The one exception I make is Smarty for templates. Since static methods do not depends on an object, they are great for factories. So please excuse any dumb, newbie questions. But you will see how the big guys structure PHP applications and you will build your own opinions. I also found the above article on that same website, but its WAY over my head. How to encourage melee combat when ranged is a stronger option. There are strong opinions about whether the singleton pattern should or should not be used, but it does have its uses. But is it always like that? This allows for an instantiated class, or public static method to access it's own private/protected static methods. PHP parse/syntax errors; and how to solve them. Im thinking of taking this one step further by using a Params object that would hold all the parameters for an object, including dependencies, and a few basic methods for getting and setting those parameters.
Going further, the object type hints in the parameters dont have to be specific classes - they can be interfaces, which means PHP will accept any class that implements that interface. Because for some objects Ill have 4-6 dependencies in addition to a few parameters, and want the ability to instantiate the object with all of that in place.
Like in this topic, when using static methods we dont have to instantiate objects so naturally we dont have a problem with that. table below shows the Phake methods that have a separate counterpart for interacting with static calls. Ah, I completely overlooked that behaviour. So even with a theoretically the best possible solution to arbitrary parameters order the final benefit remains pretty minor. But yes, I might have chosen a too extreme caching method, I would go for the private property method by default unless I had a real need for a much more global static caching. I like what he has to say, too. This doesn't produce the result you want: That's because self refers to the Car class whenever method brand() is called. Can we access the instance variables from a static method in Java? // properties, properties, static methods and methods. In fact, PHP emits a fatal error, whenever the $this variable is directly mentioned in a static method : this is why the example has to use the variable variable to actually show the status. They are called (drumroll): static classes. It is not a map of objects but for the most part a clever mechanism that will infer the dependencies from the constructor parameters and create the objects, for example this same class as earlier: The container by using reflection knows that the necessary dependencies are BlogModel and TemplateEngine and can therefore create them automatically. He suggests to have one method for instantiating each object. I have some times heard developers debating on which one is better but I think they are most powerful when used in combination. In the example, it is the x class. Passing needed objects around (as dependencies) is really a small price to pay for long-term ease of maintenance. Static is short-term while dynamic is long-term. Lets review all the five of them : The most common usage of static is for defining static methods. Im now intrigued and will try to figure out how they work and what theyre for in this context.
2021 Copyrights. Okay, Ive used that but never in a return, and I didnt know about the ?
As you can see in the example code we are defining a private static property $instance to hold the object reference. There may be many shortcomings, please advise. I am in agreement with you on this 100%. Yes, Im using Sublime Text 3. Together, they handle the Late Static Bindings. Note that static methods may be called from an object, though the pseudo-variable $this will still NOT be available. I'm worried PHP may "patch" this in future versions if this is not a valid and break my scripts.
Lets create a class and initialize four variables. current class. Because you have more control over the input and validation of those parameters and also even though more verbose it is a lot more clear what the code is doing and what is expected to happen. Thanks so much for the detailed explanation, and the Factory example. Sure, some of the solutions you wont like or will seem not useful whereas you will like others. Most of the time, these utils are PHP static classes : According to a significant part of the PHP world, it might be the same thing. Also, I presume what Db($this->getConfig()) is doing is passing in a dependency to the Db class during instantiation, is that right? DelftStack articles are written by software geeks like you. So, there is a use for static properties after all! Connect and share knowledge within a single location that is structured and easy to search.
I know this doesnt make clear what options the function needs, but I put all that in the comment block for the function, so its easy to figure out. I can achieve caching without static variables: You asked about Config returning a new instance each time so I changed it to return the same instance each time - you see, if you have a centralized place like a Factory (or DIC) to instantiate your objects its easy to change instantiation logic because it is done in one place so there is just a small piece of code to adjust. Theoretically, if you do it right then you can move the deeper layer from one framework to another and it will work because it requires all dependencies via DI and does not communicate in any other way with the outside world, the only requirement is that whatever code calls your classes provides the required dependencies. I find it easier to remember the parameter name rather than the order of each parameter. You can do it manually in the dirty way, or you can use your Factory, or you can use a DIC. Why is that property static? I can't find any real info stating it's ok to do this. Yes, I know, every time Ive mentioned this method of passing parameters to functions on a coding site no one ever seems to like it. I think the most logical place for that is just before calling new Object because this way you load only required files on demand. Instantiating all application objects every time may quickly eat your server resources, especially if you need to serve tens or hundreds requests per second. Then we start using OO with DI, which helps a lot with the code readability but then we come up with a problem of object instantiation. It is almost universally used, though there are many variations of it. But it doesnt show me all options for my custom functions as I type it out, it only does that for PHP built-in functions. Question: When using a factory container, do I load the actual class files within that container or outside the container from the main, calling script? Maintain statistics about your database tables using Laravel and triggers, Why you cant have a solid application using laravel, Clear old elements on Redis Cache with Laravel. And the static variable is local to one method only. Since this is static this reference is shared across ALL objects of this type. This allows you for quite a bit of flexibility. Why can't static method be abstract in Java? I guess I am mostly using composition, because Im not completely sure how inheritance is implemented in PHP. Is there a PRNG that visits every number exactly once, in a non-trivial bitspace, without repetition, without large memory usage, before it cycles? Static methods would be namespaced functions. cannot verify or stub all static calls. If there are too many dependencies it may be a sign that the class has too many responsibilities and its a good idea to break it into several components. Closure are functions that may be stored in a variable : functions may have their name stored in a variable, though. thanks a lot. I thought static properties and methods should be avoided. A common example is the database connection - the code that runs the main part of the application (like a router) will not do any operations straight on the database but will execute a method that does a certain task and that method will use the database as a dependency. But if I had factories, Id basically have to do the same thing, altering the factories for each class so that they recognize and inject the new dependency. Note that the variable is completely invisible from the outside world, just like a private property. Sorry I thought by saying "have code you possibly don't want to be public" was referred to the possibility of override/inherit it. But you dont have to go that far now, you can use a simple factory like this: And you instantiate one Factory object at the top of your application and then use that one instance to create your objects and execute whatever is needed for your application: and you have a very simple application based on dependency injection with no static methods! That video also mentions interfaces, and Ive read about them but didnt really understand what they are for so havent used them yet. To subscribe to this RSS feed, copy and paste this URL into your RSS reader. I tried making my own template rendering code, became too complicated and messy. If you have crazy amounts of data, its probably a bad idea to use static.
Static properties have several niche usages. Why are static properties and methods available in OOP if they should be avoided? For me, its just overkill. The first of them is being a property for a static method. When using static classes you have to use global variables as well and the biggest problem are hidden dependencies. If you are Binding: http://www.php.net/manual/en/language.oop5.late-static-bindings.php. We will initialize a method called simpleProfile(). People use this technique to store the results of previous expensive operations to optimize their script. As a general rule, its best to give everything the lowest visibility possible. This allows for an instantiated class, or public static method to access it's own private/protected static methods. I would love to have your opinion on this. Optional dependencies can be required via optional parameters in the constructor or be supplied using setter injection. The other article you linked to mentions Factories that can be used to instantiate an object with its dependencies.