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PHP - Purpose Of Interfaces?
What is the purpose of using an Interface in OOP?
I understand the textbook definition, but am not getting the extra value that they provide... TomTees Similar TutorialsSo I have been writing PHP constantly for a few months now, and have a pretty good grasp on OOP coming from other languages. One thing I never really use is interfaces, I get it when a class implements an interface, that class is required to have implemented methods from a interface, or a constant that is required by an interface. Seems like the kinda thing you would need when you are on a large team mainly for naming consistency? Is this something I should be using? I know I can get away with not using it, but should I use it to be up to modern php standards?
Thanks
I am working on a module that receives some info and provides dimensions and weights of products to the caller.
The way I get those is from existing Excel tables used by the company. Some product types have their dimensions only. Some have both dimensions and weights. To clarify - all products have both weight and dimensions but not all are specified on the Excel tables that I am using. so say "Apple" has dimensions on 1 x 1 x 1, but no weight is given. (Weight can be computed separately and in fact there is an existing class that does this already for Pear.). and "Pear" has dimensions 2 x 1 x 1 and weighs 1lbs. In short, some classes have both getWeight() and getDimensions() methods, like Pear(), and some classes just have getDimensions(), like Apple(). I am confused as to which way to go. I can create PearDimensions() class and PearWeight() and separate concepts of "weight" and "dimensions" some more and use a DimensionFactory() and WeightFactory() to instantiate the right object for the circumstances, or I can use "implements" WeightAwaretInterface and HeightAwaretInterface on Apple/Pear classes and leave them as is, thus mixing up the Weight/Dimension getters/causes. So in short I am a tad confused and wondering if there is just a good way to maintain these. Right now I am using DimensionFactory() and WeightFactory() and instantiate Pear class twice (once in each factory) since Pear has both getWeight() and getDimensions() methods. I feel weird creating the same Pear object in both factories. Do you have a recommendation for this, or do I just "hack it" (i.e. leave it as is)? Would someone help me out with Abstract Classes and Interfaces... Some questions... 1.) When you have an Interface with Methods, then any Concrete Class that "implements" said Interface must include all of the listed Methods, correct? 2.) When you have an Abstract Class with Properties & Methods, are you required to use all of the listed Properties & Methods similar to how an Interface works? 3.) What is the intent of using Abstract Classes vs. Interfaces? TomTees Hi, I am trying to get my head around classes, interfaces and methods for different animals
this is what I have so far:
<?php
interface animal {
function walk();
function fly();
function swim();
}
class monkey implements animal{
const interface1 = "I am from test class";
function noise() {
echo "ooh ooh ah ah!";
}
function walk() {
echo "monkey is walking";
}
function fly() {
echo "monkey is Flying";
}
function swim() {
echo "monkey is Swimming";
}
public function display() {
echo monkey::interface1;
echo PHP_EOL;
}
}
class bear implements animal{
const interface1 = "I am from test class";
function noise() {
echo "Grrr!";
}
function walk() {
echo "Bear is walking";
}
function fly() {
echo "Bear is Flying";
}
function swim() {
echo "Bear is Swimming";
}
public function display() {
echo bear::interface1;
echo PHP_EOL;
}
}
$Obj = new monkey();
$Obj->display();
$Obj1 = new bear();
$Obj1->display();
?>
I'm a bit stumped as animal interface not calling all functions?! please help Do interfaces in PHP include default methods, which are available in Java 7 and 8. Default methods allow you to add default functionality in the interface itself. So when a class implements it, it can use the default definition from the interface. This is in contrast to an abstract method which has no method body.
Hey guys, what's the purpose of using ob_start() in the begining of the script? I even saw alot of people turning output buffering by default in their php.ini file ! What's the benefit of this action ? Thanks in advance Can someone tell me what some of the purposes of this would be? global $PHP_SELF; its defined right after a function like this function myFunction(module =' '){ global $PHP_SELF; .... } Thanks This will be somewhat of a brain dump with somewhat vague questions. To summarize it right now, something about "refactoring software" has been bugging me. The length of the process, the work it takes, and the time, and the "no immediately visible results" that it produces.
There have been numerous questions on "do I refactor or rewrite". Depending on circumstances, one choice may work better than another, although historically for working projects (projects people are using continuously), refactoring seemed to do better, since it does not break things as much as rewriting does. And when things break all at once, such as when introducing a rewrite (which most likely has different behavior, UI, feel, workflow, etc. etc.), people tend to get upset. Well, refactoring seems to smooth out the 'upsetness' over a much longer period of time. People change as software changes, and each change is not as abrupt as with a rewrite. There are books written about refactoring software. That process takes time and work, `while not changing the functionality of the software`. Little improvements can be done here and there, but the main point becomes improving the internals of the software without affecting the outside behavior, the user experience. From the business end, *there are no changes!*. We have developers *doing busy work* without showing anything to the business, until perhaps much later. Is that bad? Where I work, I have business people scoff at "what have we been doing" quite regularly, and saying things like "add convertion from one unit system to another? Just put it in!" Which ends up me staring into vastness of legacy code and taking 2-3 weeks to "put it in", what in someone's mind takes a day at the most. But that's cuz maybe I'm slow, but I chose to refactor relevant code first, at least moving View items into respective view containers as a first step. What is the purpose of refactoring software? What, per se does it make better? What expectations can be set? What do I do next time someone says "it is taking too long", other than saying ... cuz I am refactoring! In C, when you dynamically allocate memory, you have to free it, otherwise you face memory leaks:
char *str; str = (char *) malloc(10); free(str);But in most other languages you do not need to worry about this. PHP has a function called unset, which unsets the variable's value. But why would you want to do this, if PHP has a garbage collector that will free variables once they leave scope anyway? I see no point of unset in a scripting language with garbage collection. |
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