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Posted by Jerry Stuckle on 09/05/07 00:20
Marijn wrote:
> On Sep 4, 4:52 pm, Jerry Stuckle <jstuck...@attglobal.net> wrote:
>> ELINTPimp wrote:
>>> On Sep 4, 2:40 am, Marijn <marijn.huizendv...@gmail.com> wrote:
>>>> Hi there,
>>>> Again a question with no simple yes or no answer at least, opinions
>>>> will probably be scattered so no unanimous yes or no answer ;)
>>>> What would you think is the best of the following to options given
>>>> that it is more likely that the databaseConnection is set?
>>>> SomeClass {
>>>> [.............]
>>>> /**
>>>> * Sets the connection to the database in use.
>>>> *
>>>> * @return DatabaseFactory
>>>> */
>>>> private function __getDatabaseConnection(){
>>>> if (isset($this->__databaseConnection)) {
>>>> return($this->__databaseConnection);
>>>> } else {
>>>> $this->__databaseConnection = new DatabaseFactory();
>>>> $this->__databaseConnection->create();
>>>> return($this->__databaseConnection);
>>>> };
>>>> }
>>>> }
>>>> Or
>>>> SomeClass {
>>>> [.............]
>>>> /**
>>>> * Sets the connection to the database in use.
>>>> *
>>>> * @return DatabaseFactory
>>>> */
>>>> private function __getDatabaseConnection(){
>>>> if (!$this->__databaseConnection) {
>>>> $this->__databaseConnection = new DatabaseFactory();
>>>> };
>>>> return($this->__databaseConnection);
>>>> }
>>>> }
>>>> The second option definitely has less repetitive code but does that
>>>> really make it the better option given the fact that the
>>>> databaseConnection property is probably set?
>>>> By the way, another small convention question: Should you terminate
>>>> control structures with a semicolon?
>>>> Thanks
>>>> Marijn
>>> >From looking at your code, it looks like you intend to put this
>>> connection function in all of your classes that need to talk to the
>>> database. Your code looks like it wants a singleton pattern.
>>> You're on the right path with your code, but why not abstract that
>>> logic to a class of its own (I assume mysql):
>>> class db {
>>> static private $_instance;
>>> public $connection;
>>> private __construct () {
>>> //do database initiation, such as loading config data and the like
>>> $this->connection = mysql_connect(...);
>>> //exception handling
>>> mysql_select_db($schema, $this->connection);
>>> //exception handling
>>> }
>>> public static function getInstance() {
>>> if (is_null(self::$_instance)) {
>>> self::$_instance = new db();
>>> }
>>> return self::$_instance;
>>> }
>>> } // end db class
>>> now, in your other classes, you simply type:
>>> class someClass {
>>> public function someMethod() {
>>> //just putting this in a generic method, but you could put it in
>>> the constructor, if you wish
>>> $db = db::getInstance();
>>> //and you connection handle is $db->connection
>>> }
>>> A lot less code in your classes, and a bit easier to understand in my
>>> opinion. Also has the advantages of encapsulation to the db
>>> connection so you can do fun things like centralizing exception
>>> handling and/or create some generic functions to handle your query
>>> formats, etc.
>> I do something very similar in my classes, and find it easier to use.
>>
>> However, there is a whole design concept around the Factory class, and
>> some people prefer it. It helps when you need to pass parameters to the
>> Factory, for instance, before actually creating the object.
>>
>> --
>> ==================
>> Remove the "x" from my email address
>> Jerry Stuckle
>> JDS Computer Training Corp.
>> jstuck...@attglobal.net
>> ==================
>
> Just returned from the office, boy did this get of topic ;)
>
> First My DatabaseFactory returns a singleton of a MySQL class (later
> on i can easily support other databases if i would prefer). I am
> thinking of making the DatabaseFactory itself a Singleton so that the
> Singleton logic does not need to be repeated in every database
> implementation.
>
> The reason why i have this function is that it is used in an abstract
> class for implementation of database objects in php. By extending the
> abstract class i easily can create a implementation of the database
> data with it's own methods. But i don't want to create the database
> connection before actualy using it.
>
> To solve the problem I will move my connection of the database from
> the database constructor to another function. The database resource
> can be created and only if a query method is called it will check if
> it is connected. If not connected connect else connect and query.
>
> Still i feel like people misunderstood my first question: What is
> better:
>
> if ($mostLikelyValue) {
> break;
> } else {
> performSomeAction();
> }
> theRequiredAction();
>
This has a side effect - if you're in a loop, it exits the loop. I think
you mean;
if ($mostLikelyValue) {
;
} else {
> OR
>
> if (!mostLikelyValue) {
> performSomeAction();
> }
> theRequiredAction();
>
Which I find much more readable.
> Where in my opinion the second one is more readable and the first one
> probably faster (?)
>
Speed difference will not be noticeable.
> On the naming conventions regarding access types:
>
> OK say i will go for my own path of naming variables, properties and
> parameters and there access type. Is that really more straightforward?
> I would rather have seen reserved normal function names for methods
> like __call() and __get and the
> no underscore for public, one underscore for protected and two
> underscores for private (or some other distinguishing character).
>
Don't use double underscores for anything. They should be reserved PHP
magic functions only. If you do use them, you will regret it later.
> Is there really no commonly used way (accept for the one that bluntly
> ignores protected)
>
> I really do like the way everybody mixes in and gets involved in a
> good way in these types of discussions. Thanks for that, love to hear
> more from you guys.
>
I don't worry about it. I don't have public variables, and very few
protected ones. And if I do have a protected variable, I'm looking at
the base class when developing the derived class, anyway.h
--
==================
Remove the "x" from my email address
Jerry Stuckle
JDS Computer Training Corp.
jstucklex@attglobal.net
==================
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