How can i pass a class as a parameter in my function
So far i've tried
$sc = new SampleClass();
SampleFunction($sc);
function SampleFunction(&$refClass)
{
echo $refClass->getValue();
}
this is a simplified example of what im doing.. i actually have to do complex procedures inside this sample function. I'm not getting any response from the sample function. What am i doing wrong? thank you
UPDATE
char.php
class Charss {
var $name=0;
var $hp=500;
var $spd=10;
var $rtime=10;
var $dmg=10;
function __construct( $name, $hp, $spd, $rtime , $dmg) {
$this->name = $name;
$this->hp = $hp;
$this->spd = $spd;
$this->rtime = $rtime;
$this->dmg = $dmg;
}
function get_name() {
return $this->name;
}
function set_name($new_name) {
$this->name = $new_name;
}
function get_hp() {
return $this->hp;
}
function set_hp($new_hp) {
$this->hp = $new_hp;
}
function get_spd() {
return $this->spd;
}
function set_spd($new_spd) {
$this->spd = $new_spd;
}
function get_rtime() {
return $this->rtime;
}
function set_rtime($new_rtime) {
$this->rtime = $new_rtime;
}
function get_dmg() {
return $this->get_dmg;
}
function set_dmg($new_dmg) {
$this->dmg = $new_dmg;
}
}
myclass.php
require("char.php");
class Person {
function try_process()
{
$chr1 = new Charss("Player1",500,3,0,50);
$chr2 = new Charss("Player2",500,6,0,70);
while ($chr1->get_hp() > 0 && $chr2->get_hp() > 0)
{
$sth = min($chr1->get_rtime(), $chr2->get_rtime());
if ($chr1->get_rtime() == 0 && $chr2->get_rtime() > 0)
{
exit;
Fight($chr1,$chr2);
$chr1->set_rtime($chr1->get_spd());
}
elseif ($chr2->get_rtime() == 0 && $chr1->get_rtime() > 0)
{
Fight($chr2,$chr1);
$chr2->set_rtime($chr2->get_spd());
}
else
{
Fight($chr1,$chr2); #having trouble with this
$chr1->set_rtime($chr1->get_spd());
}
$chr1->set_rtime($chr1->get_rtime() - $sth);
$chr2->set_rtime($chr2->get_rtime() - $sth);
}
}
function Fight($atk,$def)
{
$def->set_hp($def->get_hp() - $atk->get_dmg());
echo $atk->get_name() . " attacked " . $def->get_name() . " for " . $atk->get_dmg() . " damage";
}
}
so im calling the function try_process on button click
What you're actually doing there is passing an object, not a class.
$sc = new SampleClass();
creates an instance of SampleClass, aka an object.
I assume there's some error being thrown elsewhere as what you have is correct.
I tested the following code and got the expected output:
class SampleClass
{
public function getValue()
{
return 4;
}
}
$sc = new SampleClass();
SampleFunction($sc);
function SampleFunction(&$refClass)
{
echo $refClass->getValue();
}
Output: 4
If you provide more details of your actual code we might be able to determine the problem.
I can't see anything wrong with your code
using &$refClass is however is not recommended and I guess willbe removed from future iteration of PHP version
but here is an example
class objects are passed as reference I suppose so no need of '&'
http://ideone.com/GbmUy
Why is the function argument a reference? Probably shouldn't be.
Other than that, there's nothing wrong with you posted, so the error is likely within SampleClass.
Others have answered pretty well, but this is a silly little example to show you how to modify the class (either by calling a property setter, or setting public properties directly)
class foo {
private $member1;
public $member2;
public function __construct($member1,$member2) {
$this->member1=$member1;
$this->member2=$member2;
}
public function SetMember1($value) {
$this->member1 = $value;
}
public function GetMember1() {
return $this->member1;
}
}
function SetMembers(foo $obj, $member1, $member2) {
// Call a setter
$obj->SetMember1($member1);
// Set a member variable directly
$obj->member2 = $member2;
}
$obj = new foo('default member 1', 'default member 2');
echo "member1 (before): {$obj->GetMember1()}\n";
echo "member2 (before): {$obj->member2}\n";
// Change values
SetMembers($obj, 'new member1', 'new member2');
echo "member1 (after): {$obj->GetMember1()}\n";
echo "member2 (after): {$obj->member2}\n";
This will output:
member1 (before): default member 1
member2 (before): default member 2
member1 (after): new member1
member2 (after): new member2
Related
So I am facing this problem. I have a class representing a record in my database (User in this example). The class has as many properties as the database table has columns. For simplicity, I have just three in my example:
$id - ID of the user (must be set to a positive integer for registered user, might be set to 0 for user objects that aren't saved in the database yet)
$name - Name of user (must be set for every user, but before loading it from the database might be undefined)
$email - E-mail address of the user (might be NULL in case the user didn't submit an e-mail address)
My (simplified) class looks like this:
<?php
class User
{
private $id;
private $name;
private $email;
public function __construct(int $id = 0)
{
if (!empty($id)){ $this->id = $id; }
//If $id === 0, it means that the record represented by this instance isn't saved in the database yet and the property will be filled after calling the save() method
}
public function initialize(string $name = '', $email = '')
{
//If any of the parameters isn't specified, prevent overwriting curent values
if ($name === ''){ $name = $this->name; }
if ($email === ''){ $email = $this->email; }
$this->name = $name;
$this->email = $email;
}
public function load()
{
if (!empty($this->id))
{
//Load name and e-mail from the database and save them into properties
}
}
public function save()
{
if (!empty($this->id))
{
//Update existing user record in the database
}
else
{
//Insert a new record into the table and set $this->id to the ID of the last inserted row
}
}
public function isFullyLoaded()
{
$properties = get_object_vars($this);
foreach ($properties as $property)
{
if (!isset($property)){ return false; } //TODO - REPLACE isset() WITH SOMETHING ELSE
}
return true;
}
//Getters like getName() and getId() would come here
}
Now finally to my problem. As you can see, the instance of this class can be created without all properties set. That's a problem in case I want to e. g. call getName() while the name isn't known yet (it wasn't set via the initialize() method and load() wasn't called). For that, I wrote method isFullyLoaded() which checks if all properties are known and if not, load() should be called (from the method calling isFullyLoaded(). And the core of the problem is, that some variables might be empty strings (''), zero values (0) or even null (like the $email property). So I want to distinguish variables that have any value set (including null) and those who have never been assigned any value.
Specific example: I want to achieve this code:
$user1 = new User(1);
$user1->initialize('Vic', 'nerd.from.klamath#fallout2.com');
var_dump($user1->isFullyLoaded());
$user2 = new User(2);
$user2->initialize('Cassidy', null); //No e-mail was specified during the registration
var_dump($user2->isFullyLoaded());
$user3 = new User(3);
$user3->initialize('Myron'); //E-mail isn't known yet, but might be saved in the database
var_dump($user3->isFullyLoaded());
to output this:
bool(true)
bool(true)
bool(false)
TL:DR How do distinguish undefined variable and variable which has been assigned NULL in PHP?
Here is another way to introduce the custom Undefined class (as singleton). Additionally, be sure that your class properties are typed:
class Undefined
{
private static Undefined $instance;
protected function __constructor()
{
}
protected function __clone()
{
}
public function __wakeup()
{
throw new Exception("Not allowed for a singleton.");
}
static function getInstance(): Undefined
{
return self::$instance ?? (self::$instance = new static());
}
}
class Person
{
private int $age;
public function getAge(): int|Undefined
{
return $this->age ?? Undefined::getInstance();
}
}
$person = new Person();
if ($person->getAge() instanceof Undefined) {
// do something
}
But there is a downside with using singleton pattern, because all the undefined objects in your app will be strictly equal to each other. Otherwise, every get operation returning undefined value will have a side effect namely another piece of allocated RAM.
PHP has not the value undefined like javascript. But it is not strict typed so if you do not find a better solution here is one with an custom type UNDEFINED
<?php
class UNDEFINED { }
class Test {
var $a;
function __construct( $a='' ) {
$this->a = new UNDEFINED();
if( $a !== '' ) {
$this->a = $a;
}
}
function isDefined() {
$result =true;
if(gettype($this->a) === 'object'){
if(get_class($this->a) === 'UNDEFINED') {
$result=false;
}
}
echo gettype($this->a) . get_class($this->a);
return $result;
}
}
$test= new Test();
$test->isDefined();
Here is a may be litte better version which used instanceof instead of get_call and getType
<?php
class UNDEFINED { }
class Test {
var $id;
var $a;
var $b;
function __construct( $id) {
$this->id = $id;
$this->a = new UNDEFINED();
$this->b = new UNDEFINED();
}
function init( $a = '' , $b = '') {
$this->a = $this->setValue($a,$this->a);
$this->b = $this->setValue($b,$this->b);
}
function setValue($a,$default) {
return $a === '' ? $default : $a;
}
function isUndefined($a) {
return $a instanceof UNDEFINED;
}
public function isFullyLoaded()
{
$result = true;
$properties = get_object_vars($this);
print_r($properties);
foreach ($properties as $property){
$result = $result && !$this->isUndefined($property);
if ( !$result) break;
}
return $result;
}
function printStatus() {
if($this->isFullyLoaded() ) {
echo 'Loaded!';
} else {
echo 'Not loaded';
}
}
}
$test= new Test(1);
$test->printStatus();
$test->init('hello');
$test->printStatus();
$test->init('', null);
$test->printStatus();
Use property_exists():
<?php
error_reporting(E_ALL);
// oop:
class A {
public $null_var = null;
}
$a = new A;
if(property_exists($a, 'null_var')) {
echo "null_var property exists\n";
}
if(property_exists($a, 'unset_var')) {
echo "unset_var property exists\n";
}
// procedural:
$null_var = null;
if(array_key_exists('null_var', $GLOBALS)) {
echo "null_var variable exists\n";
}
if(array_key_exists('unset_var', $GLOBALS)) {
echo "unset_var variable exists\n";
}
// output:
// null_var property exists
// null_var variable exists
Say I have to similar function :
public function auth(){
return $someResponse;
}
public function collect(){
return $someOtherResponse
}
Question : When one of the response get passed to another class, is there any way to check which function returned the response ?
In a purely object-oriented way, wanting to attach information to a value is akin to wrapping it into a container possessing context information, such as:
class ValueWithContext {
private $value;
private $context;
public function __construct($value, $context) {
$this->value = $value;
$this->context = $context;
}
public value() {
return $this->value;
}
public context() {
return $this->context;
}
}
You can use it like this:
function auth()
{
return new ValueWithContext($someresponse, "auth");
}
function collect()
{
return new ValueWithContext($someotherrpesonse, "collect");
}
This forces you to be explicit about the context attached to the value, which has the benefit of protecting you from accidental renamings of the functions themselves.
As per my comment, using arrays in the return will give you a viable solution to this.
It will allow a way to see what has been done;
function auth()
{
return (array("auth" => $someresponse));
}
function collect()
{
return (array("collect" => $someotherrpesonse));
}
class myClass
{
function doSomething($type)
{
if (function_exists($type))
{
$result = $type();
if (isset($result['auth']))
{
// Auth Used
$auth_result = $result['auth'];
}
else if (isset($result['collect']))
{
// Collect used
$collect_result = $result['collect'];
}
}
}
}
It can also give you a way to fail by having a return array("fail" => "fail reason")
As comments say also, you can just check based on function name;
class myClass
{
function doSomething($type)
{
switch ($type)
{
case "auth" :
{
$result = auth();
break;
}
case "collect" :
{
$result = collect();
break;
}
default :
{
// Some error occurred?
}
}
}
}
Either way works and is perfectly valid!
Letting the two user defined functions auth() & collect() call a common function which makes a call to debug_backtrace() function should do the trick.
function setBackTrace(){
$backTraceData = debug_backtrace();
$traceObject = array_reduce($backTraceData, function ($str, $val2) {
if (trim($str) === "") {
return $val2['function'];
}
return $str . " -> " . $val2['function'];
});
return $traceObject;
}
function getfunctionDo1(){
return setBackTrace();
}
function getfunctionDo2(){
return setBackTrace();
}
class DoSomething {
static function callfunctionTodo($type){
return (($type === 1) ? getfunctionDo1() : getfunctionDo2());
}
}
echo DoSomething::callfunctionTodo(1);
echo "<br/>";
echo DoSomething::callfunctionTodo(2);
/*Output
setBackTrace -> getfunctionDo1 -> callfunctionTodo
setBackTrace -> getfunctionDo2 -> callfunctionTodo
*/
The above function would output the which function returned the response
how would it be possible to pass a type to a function, so it can check if an object is from the passed Type.
My attempt seems not to work:
class Test {
function __construct() {
}
}
function check(Type) {
$x = new Test();
if ($x instanceof Type) {
print_r("the object is from the type of the passed variable! :)");
}
}
check(Test);
If you want to instantiate the type like you have done above you can pass the classname as a string.
function check($class_str)
{
$x = new $class_str();
if($x instanceof Test) {
print_r("the object is from the type of the passed variable! :)");
}
}
check('Test');
I'm not sure I correctely understand your question but if I'm right, here is how I did a list object than can store only one specific type or object :
class DList extends DVector {
/**
* #param string $template The name of the type to store
*/
public function __construct($template){
parent::__construct();
if(!class_exists($template)){
if(in_array($template, array(self::Bool, self::Integer, self::String, self::Float, self::Map))){
$this->_template = $template;
$this->_callback = '_isTemplateType';
} else {
throw new DListTemplateTypeException('Unable to find the class "' . $template. '" ');
}
} else {
$this->_template = $template;
$this->_callback = '_isTemplateInstance';
}
}
private function _isTemplateType($value){
return gettype($value) == $this->_template;
}
private function _isTemplateInstance($value){
return $value instanceof $this->_template;
}
}
function check($type) {
$x = new Test();
if (is_subclass_of($x, $type)) {
print_r("the object is from the type of the passed variable! :)");
}
}
check("Test");
http://www.php.net/manual/en/function.is-subclass-of.php
Someone asked for an event handler that registeres variable changes in this question: PHP how to detect the change of variable?
I tried to develop a quick class with PHP's magic functions __get and __set. This works until I pass the member into a normal function by reference, it does not trigger the event anymore.
Is this a bug, or something that is not possible, or do I just miss something?
<?php
header("content-type: text/plain");
class WatchVar {
private $data = array();
private $org = array();
private $callbacks = array();
public function __set($name, $value) {
if (!array_key_exists($name, $this->data)) {
$this->org[$name] = $value;
} else {
//variable gets changed again!
$this->triggerChangedEvent($name, $value);
}
$this->data[$name] = $value;
}
public function &__get($name) {
if (array_key_exists($name, $this->data)) {
if ($this->data[$name] != $this->org[$name]) {
//variable has changed, return original
//return $this->org[$name];
//or return new state:
return $this->data[$name];
} else {
//variable has not changed
return $this->data[$name];
}
}
}
public function addCallback($name, $lambdaFunc) {
$this->callbacks[$name] = $lambdaFunc;
}
protected function triggerChangedEvent($name, $value) {
//$this->data[$name] has been changed!
//callback call like:
call_user_func($this->callbacks[$name], $value);
}
}
$test = new WatchVar;
$test->addCallback('xxx', function($newValue) { echo "xxx has changed to {$newValue}\n"; });
$test->xxx = "aaa";
echo $test->xxx . "\n";
//output: aaa
$test->xxx = "bbb";
//output: xxx has changed to bbb
echo $test->xxx . "\n";
//output bbb
function messyFunction(&$var) {
$var = "test";
}
messyFunction($test->xxx);
//output: nothing, why?
Altering this code it works:
function messyFunction(&$var) {
$var->xxx = "test";
}
messyFunction($test);
//output: xxx has changed to test
//output: nothing, why?
Even passed by reference, the function only recieves a clone of the member variable instead of the instance + magic functions.
is there a better way to call an anonymous function inside a class? Here is a simple example that clearifies what I mean.
class foo
{
private $call_back_1 = null;
private $call_back_2 = null;
function __construct($func1, $func2)
{
$this->call_back_1 = func1;
$this->call_back_2 = func2;
}
function provokeCallBacks()
{
//this does not work, and gives an error
$this->call_back_1();
//I would like to avoid this
$method = $this->call_back_2;
$method();
}
}
$call1 = function(){ echo "inside call 1"};
$call2 = function(){ echo "inside call 2"};
$test = new foo(call1, call2);
$test->provokeCallBacks();
* Update 1: Please ignore any syntax error as I have written this on the fly for demo puposes. *
Inside foo:provokeCallBacks, I am trying to call the anonymous functions how ever the first way does not works and gives an error. The second one works but it's a bit stupid that I have to use a temp variable called "$method" to make the call.
I want to know if there exists a better way to call the anonymous function.
call_user_func($this->call_back_1);
No, it's not possible to call an anonymous function via $this.
Another options is;
call_user_func($this->call_back_1);
Being PHP loosely typed, it can't do like {$this -> callback}(); you have to store it in a temp variable or to use call_user_func() either.
EDIT - consider something like this:
class Lambdas
{
protected $double;
protected $triple;
public function __construct($double, $triple)
{
$this -> double = $double;
$this -> triple = $triple;
}
public function __call($name, $arguments)
{
if( is_callable($this -> {$name}) ){
return call_user_func_array($this -> {$name}, $arguments);
}
}
}
$lambdas = new Lambdas(
function($a){ return $a * 2;},
function($a){ return $a * 3;}
);
echo $lambdas -> double(2); // prints 4
echo $lambdas -> triple(2); // prints 6
Dirty and dangerous, but you might succeed using eval..
class foo
{
private $call_back_1 = null;
private $call_back_2 = null;
function __construct($func1, $func2)
{
$this->call_back_1 = func1;
$this->call_back_2 = func2;
}
function provokeCallBacks()
{
eval($this->call_back_1);
eval($this->call_back_2);
}
}
call1 = 'echo "inside call 1"';
call2 = 'echo "inside call 2"';
$test = foo(call1, call2);
$test->provokeCallBacks();
I know your question has been answered but you can try changing your approch ..
class Foo {
private $calls = array();
function __set($key, $value) {
$this->calls[$key] = $value;
}
function __call($name, $arg) {
if (array_key_exists($name, $this->calls)) {
$this->calls[$name]();
}
}
function __all() {
foreach ( $this->calls as $call ) {
$call();
}
}
}
$test = new Foo();
$test->A = function () {
echo "inside call 1";
};
$test->B = function () {
echo "inside call 2";
};
$test->A(); // inside call 1
$test->B(); // inside call 2
$test->__all(); // inside call 1 & inside call 2