I am working on a PHP class which looks like this:
<?php
class xyz{
public $car1;
public $car2;
private $owner;
public function __construct ($type){
$this->car1 = $type;
$this->owner = "John";
return $this->owner();
}
private function owner(){
return "Owner of ".$this->car1." is ".$this->owner;
}
Now, here's the problem when I call this class via other code, I can easily access private variable and the return function is not working correctly.
Here's the sample:
<?php
$car = new xyz("Sedan");
echo $car; //Expected result: Owner of Sedan is John.
?>
If I print $car, Here's what I get
Object ( [car1] => Sedan [car2] => "" [owner:xyz:private] => John )
How can I achieve my desired results and How can I protect private variable?
All the helps and suggestions will be appreciated.
Thanks!
Constructors are not supposed to return any value. The class constructor is supposed to initialize an object when creating a new instance (e.g. when you write $car = new xyz("sedan");, so anything you return goes nowhere. Create other methods in the class to return values.
If you want to echo the owner, make the owner method public and do `echo $car->owner();". The method returns a string, and then the string is echoed. Simple.
Echoing the object directly should result in an error in php 7, maybe you are running an older version of php that returns what you've seen, which is what happens if you call var_dump($car);. If you want to control how an object is converted into a string, you need to override the __toString method (see the php documentation).
Properties and methods visibility keywords are working fine, if you try to use $car->owner or $car->owner() without changing visibility you should see errors.
Related
I have a object having some protected property that I want to get and set. The object looks like
Fields_Form_Element_Location Object
(
[helper] => formText
[_allowEmpty:protected] => 1
[_autoInsertNotEmptyValidator:protected] => 1
[_belongsTo:protected] =>
[_description:protected] =>
[_disableLoadDefaultDecorators:protected] =>
[_errorMessages:protected] => Array
(
)
[_errors:protected] => Array
(
)
[_isErrorForced:protected] =>
[_label:protected] => Current City
[_value:protected] => 93399
[class] => field_container field_19 option_1 parent_1
)
I want to get value property of the object. When I try $obj->_value or $obj->value it generates error. I searched and found the solution to use PHP Reflection Class. It worked on my local but on server PHP version is 5.2.17 So I cannot use this function there. So any solution how to get such property?
Here's the really simple example (with no error checking) of how to use ReflectionClass:
function accessProtected($obj, $prop) {
$reflection = new ReflectionClass($obj);
$property = $reflection->getProperty($prop);
$property->setAccessible(true);
return $property->getValue($obj);
}
I know you said you were limited to 5.2, but that was 2 years ago, 5.5 is the oldest supported version and I'm hoping to help people with modern versions.
Object can be typecasted into (associative) array and the protected members have keys prefixed with chr(0).'*'.chr(0) (see #fardelian's comment here). Using this undocummented feature you can write an "exposer":
function getProtectedValue($obj, $name) {
$array = (array)$obj;
$prefix = chr(0).'*'.chr(0);
return $array[$prefix.$name];
}
Alternatively, you can parse the value from serialized string, where (it seems) protected members have the same prefix.
This works in PHP 5.2 without the overhead of ReflectionClass. However, there are reasons why some property is protected and hidden from client code. The reading or writing can make the data inconsistent or the author provides some other way to expose it in effort to make the interface as lean as possible. When there are reasons to read the protected property directly, the then-correct approach was to implement __get() magic method, so always check if there is any and see what it does. This counter intuitive lookup was finally solved in PHP 8.1 with readonly properties.
Since PHP 8.0, there also attributes metadata accessible by ReflectionClass, make sure to check them also before performing attempts to break into protected members. Attributes superseded "Annotations"1, so check them, too.
1: annotations are a very nasty surprise to client coders: they parse comments to add crazy fancy black-box useless confusing functionality, should not be used anymore, but they still exist
That's what "protected" is meant for, as the Visibility chapter explains:
Members declared protected can be accessed only within the class itself and by inherited and parent classes.
If you need to access the property from outside, pick one:
Don't declare it as protected, make it public instead
Write a couple of functions to get and set the value (getters and setters)
If you don't want to modify the original class (because it's a third-party library you don't want to mess) create a custom class that extends the original one:
class MyFields_Form_Element_Location extends Fields_Form_Element_Location{
}
... and add your getter/setter there.
If you want to tinker with a class without adding getters and setters....
PHP 7 adds a call($obj) method (faster than old bindTo) on closures allowing you to call a function so the $this variable will act just as it would within a class -with full permissions.
//test class with restricted properties
class test{
protected $bar="protected bar";
private $foo="private foo";
public function printProperties(){
echo $this->bar."::".$this->foo;
}
}
$testInstance=new test();
//we can change or read the restricted properties by doing this...
$change=function(){
$this->bar="I changed bar";
$this->foo="I changed foo";
};
$change->call($testInstance);
$testInstance->printProperties();
//outputs I changed bar::I changed foo in php 7.0
For PHP 7.4+, we can use an Arrow Function and the Closure::call to access private and protected members using just one small line:
PHP 7.4+
Retrieving protected/private members:
class Test {
protected $data = 'Protected variable!';
}
// Will output "Protected variable!"
echo (fn() => $this->data)->call(new Test);
Altering protected/private members:
class Test {
protected $data = 'Testing';
}
$test = new Test;
(fn() => $this->data = "New Data!")->call($test);
// Will output "New Data!"
echo (fn() => $this->data)->call($test);
Of course, we can use a normal Closure function if we want to alter/use multiple members:
class Test {
protected $data = 'Data!';
}
$test = new Test;
(function() {
$this->new_data = "New {$this->data}";
})->call($test);
// Will output "New Data!"
echo (fn() => $this->new_data)->call($test);
If you cannot modify the original class and extending it is not an option either, you can use the ReflectionProperty interface.
The phptoolcase library has a handy method for this:
$value = PtcHandyMan::getProperty($your_object , 'propertyName');
Static property from a singleton class:
$value = PtcHandyMan::getProperty('myCLassName', 'propertyName');
You can find the tool here: http://phptoolcase.com/guides/ptc-hm-guide.html
$a=json_encode((array)$obj);
$b=(array)json_decode(str_replace('\u0000*\u0000','',$a));
echo($b['value']);
What I like to do is declare every property that would be writable from outside as public. The properties that you want to be visible for the outside world but not writable you should declare as protected and write __get() magic method so you can read them. Example:
/**
* Class Test
*
* #property int $protected
*
*/
class Test
{
private const READABLE = ['protected'];
protected $protected = 1;
public $public = 2;
public function __get($property)
{
//if you want to read every protected or private
return $this->$property ?? null;
//if you want only some protected and private values to be readable
if (in_array($property, self::READABLE)) {
return $this->$property;
}
}
}
$test = new Test();
echo $test->protected; //outputs 1
echo $test->public; //outputs 2
$test->protected = 3; //outputs error - protected property
The best would be to have property declaration like:
public readonly $protected = 1; //only readable from the outside
public $public = 2; //readable and writable from the outside
but no such syntax exists yet(or... at least I don't know about it). P.S. you should declare the protected/private properties that will be readable in the Class DockBlock as shown, so you can autocomplete them, otherwise you will be able to access them, but your IDE won't recognize them on autocomplete when you are writing code.
I have a object having some protected property that I want to get and set. The object looks like
Fields_Form_Element_Location Object
(
[helper] => formText
[_allowEmpty:protected] => 1
[_autoInsertNotEmptyValidator:protected] => 1
[_belongsTo:protected] =>
[_description:protected] =>
[_disableLoadDefaultDecorators:protected] =>
[_errorMessages:protected] => Array
(
)
[_errors:protected] => Array
(
)
[_isErrorForced:protected] =>
[_label:protected] => Current City
[_value:protected] => 93399
[class] => field_container field_19 option_1 parent_1
)
I want to get value property of the object. When I try $obj->_value or $obj->value it generates error. I searched and found the solution to use PHP Reflection Class. It worked on my local but on server PHP version is 5.2.17 So I cannot use this function there. So any solution how to get such property?
Here's the really simple example (with no error checking) of how to use ReflectionClass:
function accessProtected($obj, $prop) {
$reflection = new ReflectionClass($obj);
$property = $reflection->getProperty($prop);
$property->setAccessible(true);
return $property->getValue($obj);
}
I know you said you were limited to 5.2, but that was 2 years ago, 5.5 is the oldest supported version and I'm hoping to help people with modern versions.
Object can be typecasted into (associative) array and the protected members have keys prefixed with chr(0).'*'.chr(0) (see #fardelian's comment here). Using this undocummented feature you can write an "exposer":
function getProtectedValue($obj, $name) {
$array = (array)$obj;
$prefix = chr(0).'*'.chr(0);
return $array[$prefix.$name];
}
Alternatively, you can parse the value from serialized string, where (it seems) protected members have the same prefix.
This works in PHP 5.2 without the overhead of ReflectionClass. However, there are reasons why some property is protected and hidden from client code. The reading or writing can make the data inconsistent or the author provides some other way to expose it in effort to make the interface as lean as possible. When there are reasons to read the protected property directly, the then-correct approach was to implement __get() magic method, so always check if there is any and see what it does. This counter intuitive lookup was finally solved in PHP 8.1 with readonly properties.
Since PHP 8.0, there also attributes metadata accessible by ReflectionClass, make sure to check them also before performing attempts to break into protected members. Attributes superseded "Annotations"1, so check them, too.
1: annotations are a very nasty surprise to client coders: they parse comments to add crazy fancy black-box useless confusing functionality, should not be used anymore, but they still exist
That's what "protected" is meant for, as the Visibility chapter explains:
Members declared protected can be accessed only within the class itself and by inherited and parent classes.
If you need to access the property from outside, pick one:
Don't declare it as protected, make it public instead
Write a couple of functions to get and set the value (getters and setters)
If you don't want to modify the original class (because it's a third-party library you don't want to mess) create a custom class that extends the original one:
class MyFields_Form_Element_Location extends Fields_Form_Element_Location{
}
... and add your getter/setter there.
If you want to tinker with a class without adding getters and setters....
PHP 7 adds a call($obj) method (faster than old bindTo) on closures allowing you to call a function so the $this variable will act just as it would within a class -with full permissions.
//test class with restricted properties
class test{
protected $bar="protected bar";
private $foo="private foo";
public function printProperties(){
echo $this->bar."::".$this->foo;
}
}
$testInstance=new test();
//we can change or read the restricted properties by doing this...
$change=function(){
$this->bar="I changed bar";
$this->foo="I changed foo";
};
$change->call($testInstance);
$testInstance->printProperties();
//outputs I changed bar::I changed foo in php 7.0
For PHP 7.4+, we can use an Arrow Function and the Closure::call to access private and protected members using just one small line:
PHP 7.4+
Retrieving protected/private members:
class Test {
protected $data = 'Protected variable!';
}
// Will output "Protected variable!"
echo (fn() => $this->data)->call(new Test);
Altering protected/private members:
class Test {
protected $data = 'Testing';
}
$test = new Test;
(fn() => $this->data = "New Data!")->call($test);
// Will output "New Data!"
echo (fn() => $this->data)->call($test);
Of course, we can use a normal Closure function if we want to alter/use multiple members:
class Test {
protected $data = 'Data!';
}
$test = new Test;
(function() {
$this->new_data = "New {$this->data}";
})->call($test);
// Will output "New Data!"
echo (fn() => $this->new_data)->call($test);
If you cannot modify the original class and extending it is not an option either, you can use the ReflectionProperty interface.
The phptoolcase library has a handy method for this:
$value = PtcHandyMan::getProperty($your_object , 'propertyName');
Static property from a singleton class:
$value = PtcHandyMan::getProperty('myCLassName', 'propertyName');
You can find the tool here: http://phptoolcase.com/guides/ptc-hm-guide.html
$a=json_encode((array)$obj);
$b=(array)json_decode(str_replace('\u0000*\u0000','',$a));
echo($b['value']);
What I like to do is declare every property that would be writable from outside as public. The properties that you want to be visible for the outside world but not writable you should declare as protected and write __get() magic method so you can read them. Example:
/**
* Class Test
*
* #property int $protected
*
*/
class Test
{
private const READABLE = ['protected'];
protected $protected = 1;
public $public = 2;
public function __get($property)
{
//if you want to read every protected or private
return $this->$property ?? null;
//if you want only some protected and private values to be readable
if (in_array($property, self::READABLE)) {
return $this->$property;
}
}
}
$test = new Test();
echo $test->protected; //outputs 1
echo $test->public; //outputs 2
$test->protected = 3; //outputs error - protected property
The best would be to have property declaration like:
public readonly $protected = 1; //only readable from the outside
public $public = 2; //readable and writable from the outside
but no such syntax exists yet(or... at least I don't know about it). P.S. you should declare the protected/private properties that will be readable in the Class DockBlock as shown, so you can autocomplete them, otherwise you will be able to access them, but your IDE won't recognize them on autocomplete when you are writing code.
I have a object having some protected property that I want to get and set. The object looks like
Fields_Form_Element_Location Object
(
[helper] => formText
[_allowEmpty:protected] => 1
[_autoInsertNotEmptyValidator:protected] => 1
[_belongsTo:protected] =>
[_description:protected] =>
[_disableLoadDefaultDecorators:protected] =>
[_errorMessages:protected] => Array
(
)
[_errors:protected] => Array
(
)
[_isErrorForced:protected] =>
[_label:protected] => Current City
[_value:protected] => 93399
[class] => field_container field_19 option_1 parent_1
)
I want to get value property of the object. When I try $obj->_value or $obj->value it generates error. I searched and found the solution to use PHP Reflection Class. It worked on my local but on server PHP version is 5.2.17 So I cannot use this function there. So any solution how to get such property?
Here's the really simple example (with no error checking) of how to use ReflectionClass:
function accessProtected($obj, $prop) {
$reflection = new ReflectionClass($obj);
$property = $reflection->getProperty($prop);
$property->setAccessible(true);
return $property->getValue($obj);
}
I know you said you were limited to 5.2, but that was 2 years ago, 5.5 is the oldest supported version and I'm hoping to help people with modern versions.
Object can be typecasted into (associative) array and the protected members have keys prefixed with chr(0).'*'.chr(0) (see #fardelian's comment here). Using this undocummented feature you can write an "exposer":
function getProtectedValue($obj, $name) {
$array = (array)$obj;
$prefix = chr(0).'*'.chr(0);
return $array[$prefix.$name];
}
Alternatively, you can parse the value from serialized string, where (it seems) protected members have the same prefix.
This works in PHP 5.2 without the overhead of ReflectionClass. However, there are reasons why some property is protected and hidden from client code. The reading or writing can make the data inconsistent or the author provides some other way to expose it in effort to make the interface as lean as possible. When there are reasons to read the protected property directly, the then-correct approach was to implement __get() magic method, so always check if there is any and see what it does. This counter intuitive lookup was finally solved in PHP 8.1 with readonly properties.
Since PHP 8.0, there also attributes metadata accessible by ReflectionClass, make sure to check them also before performing attempts to break into protected members. Attributes superseded "Annotations"1, so check them, too.
1: annotations are a very nasty surprise to client coders: they parse comments to add crazy fancy black-box useless confusing functionality, should not be used anymore, but they still exist
That's what "protected" is meant for, as the Visibility chapter explains:
Members declared protected can be accessed only within the class itself and by inherited and parent classes.
If you need to access the property from outside, pick one:
Don't declare it as protected, make it public instead
Write a couple of functions to get and set the value (getters and setters)
If you don't want to modify the original class (because it's a third-party library you don't want to mess) create a custom class that extends the original one:
class MyFields_Form_Element_Location extends Fields_Form_Element_Location{
}
... and add your getter/setter there.
If you want to tinker with a class without adding getters and setters....
PHP 7 adds a call($obj) method (faster than old bindTo) on closures allowing you to call a function so the $this variable will act just as it would within a class -with full permissions.
//test class with restricted properties
class test{
protected $bar="protected bar";
private $foo="private foo";
public function printProperties(){
echo $this->bar."::".$this->foo;
}
}
$testInstance=new test();
//we can change or read the restricted properties by doing this...
$change=function(){
$this->bar="I changed bar";
$this->foo="I changed foo";
};
$change->call($testInstance);
$testInstance->printProperties();
//outputs I changed bar::I changed foo in php 7.0
For PHP 7.4+, we can use an Arrow Function and the Closure::call to access private and protected members using just one small line:
PHP 7.4+
Retrieving protected/private members:
class Test {
protected $data = 'Protected variable!';
}
// Will output "Protected variable!"
echo (fn() => $this->data)->call(new Test);
Altering protected/private members:
class Test {
protected $data = 'Testing';
}
$test = new Test;
(fn() => $this->data = "New Data!")->call($test);
// Will output "New Data!"
echo (fn() => $this->data)->call($test);
Of course, we can use a normal Closure function if we want to alter/use multiple members:
class Test {
protected $data = 'Data!';
}
$test = new Test;
(function() {
$this->new_data = "New {$this->data}";
})->call($test);
// Will output "New Data!"
echo (fn() => $this->new_data)->call($test);
If you cannot modify the original class and extending it is not an option either, you can use the ReflectionProperty interface.
The phptoolcase library has a handy method for this:
$value = PtcHandyMan::getProperty($your_object , 'propertyName');
Static property from a singleton class:
$value = PtcHandyMan::getProperty('myCLassName', 'propertyName');
You can find the tool here: http://phptoolcase.com/guides/ptc-hm-guide.html
$a=json_encode((array)$obj);
$b=(array)json_decode(str_replace('\u0000*\u0000','',$a));
echo($b['value']);
What I like to do is declare every property that would be writable from outside as public. The properties that you want to be visible for the outside world but not writable you should declare as protected and write __get() magic method so you can read them. Example:
/**
* Class Test
*
* #property int $protected
*
*/
class Test
{
private const READABLE = ['protected'];
protected $protected = 1;
public $public = 2;
public function __get($property)
{
//if you want to read every protected or private
return $this->$property ?? null;
//if you want only some protected and private values to be readable
if (in_array($property, self::READABLE)) {
return $this->$property;
}
}
}
$test = new Test();
echo $test->protected; //outputs 1
echo $test->public; //outputs 2
$test->protected = 3; //outputs error - protected property
The best would be to have property declaration like:
public readonly $protected = 1; //only readable from the outside
public $public = 2; //readable and writable from the outside
but no such syntax exists yet(or... at least I don't know about it). P.S. you should declare the protected/private properties that will be readable in the Class DockBlock as shown, so you can autocomplete them, otherwise you will be able to access them, but your IDE won't recognize them on autocomplete when you are writing code.
I have a object having some protected property that I want to get and set. The object looks like
Fields_Form_Element_Location Object
(
[helper] => formText
[_allowEmpty:protected] => 1
[_autoInsertNotEmptyValidator:protected] => 1
[_belongsTo:protected] =>
[_description:protected] =>
[_disableLoadDefaultDecorators:protected] =>
[_errorMessages:protected] => Array
(
)
[_errors:protected] => Array
(
)
[_isErrorForced:protected] =>
[_label:protected] => Current City
[_value:protected] => 93399
[class] => field_container field_19 option_1 parent_1
)
I want to get value property of the object. When I try $obj->_value or $obj->value it generates error. I searched and found the solution to use PHP Reflection Class. It worked on my local but on server PHP version is 5.2.17 So I cannot use this function there. So any solution how to get such property?
Here's the really simple example (with no error checking) of how to use ReflectionClass:
function accessProtected($obj, $prop) {
$reflection = new ReflectionClass($obj);
$property = $reflection->getProperty($prop);
$property->setAccessible(true);
return $property->getValue($obj);
}
I know you said you were limited to 5.2, but that was 2 years ago, 5.5 is the oldest supported version and I'm hoping to help people with modern versions.
Object can be typecasted into (associative) array and the protected members have keys prefixed with chr(0).'*'.chr(0) (see #fardelian's comment here). Using this undocummented feature you can write an "exposer":
function getProtectedValue($obj, $name) {
$array = (array)$obj;
$prefix = chr(0).'*'.chr(0);
return $array[$prefix.$name];
}
Alternatively, you can parse the value from serialized string, where (it seems) protected members have the same prefix.
This works in PHP 5.2 without the overhead of ReflectionClass. However, there are reasons why some property is protected and hidden from client code. The reading or writing can make the data inconsistent or the author provides some other way to expose it in effort to make the interface as lean as possible. When there are reasons to read the protected property directly, the then-correct approach was to implement __get() magic method, so always check if there is any and see what it does. This counter intuitive lookup was finally solved in PHP 8.1 with readonly properties.
Since PHP 8.0, there also attributes metadata accessible by ReflectionClass, make sure to check them also before performing attempts to break into protected members. Attributes superseded "Annotations"1, so check them, too.
1: annotations are a very nasty surprise to client coders: they parse comments to add crazy fancy black-box useless confusing functionality, should not be used anymore, but they still exist
That's what "protected" is meant for, as the Visibility chapter explains:
Members declared protected can be accessed only within the class itself and by inherited and parent classes.
If you need to access the property from outside, pick one:
Don't declare it as protected, make it public instead
Write a couple of functions to get and set the value (getters and setters)
If you don't want to modify the original class (because it's a third-party library you don't want to mess) create a custom class that extends the original one:
class MyFields_Form_Element_Location extends Fields_Form_Element_Location{
}
... and add your getter/setter there.
If you want to tinker with a class without adding getters and setters....
PHP 7 adds a call($obj) method (faster than old bindTo) on closures allowing you to call a function so the $this variable will act just as it would within a class -with full permissions.
//test class with restricted properties
class test{
protected $bar="protected bar";
private $foo="private foo";
public function printProperties(){
echo $this->bar."::".$this->foo;
}
}
$testInstance=new test();
//we can change or read the restricted properties by doing this...
$change=function(){
$this->bar="I changed bar";
$this->foo="I changed foo";
};
$change->call($testInstance);
$testInstance->printProperties();
//outputs I changed bar::I changed foo in php 7.0
For PHP 7.4+, we can use an Arrow Function and the Closure::call to access private and protected members using just one small line:
PHP 7.4+
Retrieving protected/private members:
class Test {
protected $data = 'Protected variable!';
}
// Will output "Protected variable!"
echo (fn() => $this->data)->call(new Test);
Altering protected/private members:
class Test {
protected $data = 'Testing';
}
$test = new Test;
(fn() => $this->data = "New Data!")->call($test);
// Will output "New Data!"
echo (fn() => $this->data)->call($test);
Of course, we can use a normal Closure function if we want to alter/use multiple members:
class Test {
protected $data = 'Data!';
}
$test = new Test;
(function() {
$this->new_data = "New {$this->data}";
})->call($test);
// Will output "New Data!"
echo (fn() => $this->new_data)->call($test);
If you cannot modify the original class and extending it is not an option either, you can use the ReflectionProperty interface.
The phptoolcase library has a handy method for this:
$value = PtcHandyMan::getProperty($your_object , 'propertyName');
Static property from a singleton class:
$value = PtcHandyMan::getProperty('myCLassName', 'propertyName');
You can find the tool here: http://phptoolcase.com/guides/ptc-hm-guide.html
$a=json_encode((array)$obj);
$b=(array)json_decode(str_replace('\u0000*\u0000','',$a));
echo($b['value']);
What I like to do is declare every property that would be writable from outside as public. The properties that you want to be visible for the outside world but not writable you should declare as protected and write __get() magic method so you can read them. Example:
/**
* Class Test
*
* #property int $protected
*
*/
class Test
{
private const READABLE = ['protected'];
protected $protected = 1;
public $public = 2;
public function __get($property)
{
//if you want to read every protected or private
return $this->$property ?? null;
//if you want only some protected and private values to be readable
if (in_array($property, self::READABLE)) {
return $this->$property;
}
}
}
$test = new Test();
echo $test->protected; //outputs 1
echo $test->public; //outputs 2
$test->protected = 3; //outputs error - protected property
The best would be to have property declaration like:
public readonly $protected = 1; //only readable from the outside
public $public = 2; //readable and writable from the outside
but no such syntax exists yet(or... at least I don't know about it). P.S. you should declare the protected/private properties that will be readable in the Class DockBlock as shown, so you can autocomplete them, otherwise you will be able to access them, but your IDE won't recognize them on autocomplete when you are writing code.
How to combine two variables to obtain / create new variable?
public $show_diary = 'my';
private my_diary(){
return 1;
}
public view_diary(){
return ${"this->"}.$this->show_diary.{"_diary()"}; // 1
return $this->.{"$this->show_diary"}._diary() // 2
}
both return nothing.
Your class should be like following:
class Test
{
public $show_diary;
function __construct()
{
$this->show_diary = "my";
}
private function my_diary(){
return 707;
}
public function view_diary(){
echo $this->{$this->show_diary."_diary"}(); // 707
}
}
It almost looks from your question like you are asking about how to turn simple variables into objects and then how to have one object contain another one. I could be way off, but I hope not:
So, first off, what is the differnce between an object and a simple variable? An object is really a collection of (generally) at least one property, which is sort of like a variable within it, and very often functions which do things to the properties of the object. Basically an object is like a complex variable.
In PHP, we need to first declare the strucutre of the object, this is done via a class statement, where we basicaly put the skeleton of what the object will be into place. This is done by the class statement. However, at this point, it hasn't actually been created, it is just like a plan for it when it is created later.
The creation is done via a command like:
$someVariable= new diary();
This executes so create a new variable, and lays it out with the structure, properties and functions defined in the class statement.
From then on, you can access various properties or call functions within it.
class show_diary
{
public $owner;
public function __construct()
{
$this->owner='My';
}
}
class view_diary
{
public $owner;
public $foo;
public function __construct()
{
$this->foo='bar';
$this->owner=new show_diary();
}
}
$diary= new view_diary();
print_r($diary);
The code gives us two classes. One of the classes has an instance of the other class within it.
I have used constructors, which are a special type of function that is executed each time we create a new instance of a class - basically each time we declare a variable of that type, the __construct function is called.
When the $diary= new view_diary(); code is called, it creates an instance of the view_diary class, and in doing so, the first thing it does is assigns it's own foo property to have the value 'bar' in it. Then, it sets it's owner property to be an instance of show_diary which in turn then kicks off the __construct function within the new instance. That in turn assigns the owner property of the child item to have the value 'My'.
If you want to access single properties of the object, you can do so by the following syntax:
echo $diary->foo;
To access a property of an object inside the object, you simply add more arrows:
echo $diary->owner->owner;
Like this?
$diary = $this->show_diary . '_diary';
return $this->$diary();