I have this array:
$methodsOutput = array("MidUpperArmMuscleArea","ArmSpan_HeightEstimation","BMIBeforePregnancy",
"PregnancyTotalWeightGain","PregnancyWeeklyWeightGain","MS_CurrentBMI_BMIPregnancyWeeks",
"PregnancyDueDate","PregnancyWeeks","WeightEstimation","WHO_BMI_2000_IdealBMI",
"WHO_BMI_2000_IdealWeight","WHO_HeightAge_2006_IdealHeight","WHO_WeightAge_2006_IdealWeight");
and for each one I have the respective class (all included in file).
How can I instantiate dynamically this.
I try this:
foreach($methodsOutput as $method) {
$$method= new $method();
}
but get:
Fatal error: Class 'MidUpperArmMuscleArea' not found in...
Objectively, this looks like a really bad way of doing this..
Anyway, that's not what you want to hear.
The class 'MidUpperArmMuscleArea' must really not exist in that context, as your syntax is correct. Since you mention all these classes are in the same file, are you defining them after you are executing this code?
Do you have that class "MidUpperArmMuscleArea" ?
You could to use class_exists to test.
Related
I know you can call static methods using variable as class name like so:
$className = "Foo";
$className::Bar(); //works
But when i'm trying to use static property as variable like this:
self::$className = "Foo";
self::$className::Bar(); //doesn't
it gives me the following parse error on line where i'm trying to call the method:
Parse error: syntax error, unexpected '::' (T_PAAMAYIM_NEKUDOTAYIM)
So how can i call that method using static property and is that even possible with syntax somewhat similar to what i described(w/o call_user_func and creating local variable that stores self::$className)?
You could do that:
$tmp = self::$className;
$tmp::Bar();
Edit
Based on your comments it seems your problem is more about OOP design than it is about syntax. Furthermore, you keep adding new restrictions every time a solution is given, which makes it difficult to provide a relevant answer.
Anyway, I'll try to summarize your options. The syntax you want does not exist (at the moment, anyway), so you have to work around it one way or another. Yes, this is annoying, and yes this means that you will have to make concessions. But that's how it is.
Here are your options so far:
Use call_user_func or forward_static_call or similar.
Use a temporary local variable. Possibly wrap that into a method if it's really bothering you (e.g. static function call($method) { $tmp = self::$classname; return $tmp::$method(); } and then use self::call('bar');)
Refactor your object design using instances instead of static methods so that you don't need to do that anymore.
Use some other terribly ugly and dangerous hack (e.g. eval(self::$classname.'::bar();'); and hope it won't come bite you in the butt.
I've been creating a script using PHP and seem to have hit a brick wall at the moment with it. I'm trying to call a variable from another file which is within a class, so I went about it by including the file within the original and then instantiating the class to call the variable. But the entire thing is within a recursive function and I get Fatal error: Cannot redeclare class JVersion. I've pasted part of the code below:
...
function functionname($path)
{
...
define('_JEXEC', true);
require_once ($path ."libraries/cms/version/version.php");
$test_class = new JVersion();
$jma_ver = $test_class->getShortVersion();
...
functionname($path);
...
}
This is how the part of the code within the version.php looks like
defined('_JEXEC') or die;
final class JVersion
{
public $RELEASE = '2.5';
public $DEV_LEVEL = '1';
public function getShortVersion()
{
return $this->RELEASE.'.'.$this->DEV_LEVEL;
}
Is there a way I can overcome the "Fatal error: Cannot redeclare class JVersion" error ?
If I understand the problem correctly (i.e. you have many classes named JVersion that you need to use), then I'm not sure of any way around this problem without namespacing your JVersion classes in some way. Either give them distinct names or put them in different PHP namespaces.
This sounds more like an architectural problem, really; the code you're using doesn't seem to provide a way of getting its version in a disposable manner (without setting yourself up for conflicts like this). Ideally, you should just have a global JVersion class that can be insantiated with the appropriate version numbers; this way there'd be no class name conflicts.
Does anyone know what can cause this problem?
PHP Fatal error: Cannot redeclare class
You have a class of the same name declared more than once. Maybe via multiple includes. When including other files you need to use something like
include_once "something.php";
to prevent multiple inclusions. It's very easy for this to happen, though not always obvious, since you could have a long chain of files being included by one another.
It means you've already created a class.
For instance:
class Foo {}
// some code here
class Foo {}
That second Foo would throw the error.
That happens when you declare a class more than once in a page.
You can fix it by either wrapping that class with an if statement (like below), or you can put it into a separate file and use require_once(), instead of include().
if (!class_exists('TestClass')) {
// Put class TestClass here
}
Use include_once(); - with this, your codes will be included only one time.
This will happen if we use any of the in built classes in the php library. I used the class name as Directory and I got the same error. If you get error first make sure that the class name you use is not one of the in built classes.
This error might also occur if you define the __construct method more than once.
Sometimes that happens due to some bugs in PHP's FastCGI.
Try to restart it. At Ubuntu it's:
service php-fastcgi restart
I had the same problem while using autoload like follows:
<?php
function __autoload($class_name)
{
include $class_name . '.php';
}
__autoload("MyClass1");
$obj = new MyClass1();
?>
and in other class there was:
namespace testClassNamespace;
class MyClass1
{
function __construct()
{
echo "MyClass1 constructor";
}
}
The sollution is to keep namespace compatibility, in my example namespace testClassNamespace; in both files.
Just adding;
This error can also occur if you by mistake put a function inside another function.
PHP 5.3 (an I think older versions too) seems to have problem with same name in different cases. So I had this problem when a had the class Login and the interface it implements LogIn. After I renamed LogIn to Log_In the problem got solved.
Just do one thing whenever you include or require filename namely class.login.php. You can include it this way:
include_once class.login.php or
require_once class.login.php
This way it never throws an error.
This function will print a stack telling you where it was called from:
function PrintTrace() {
$trace = debug_backtrace();
echo '<pre>';
$sb = array();
foreach($trace as $item) {
if(isset($item['file'])) {
$sb[] = htmlspecialchars("$item[file]:$item[line]");
} else {
$sb[] = htmlspecialchars("$item[class]:$item[function]");
}
}
echo implode("\n",$sb);
echo '</pre>';
}
Call this function at the top of the file that includes your class.
Sometimes it will only print once, even though your class is being included two or more times. This is because PHP actually parses all the top-level classes in a file before executing any code and throws the fatal error immediately. To remedy this, wrap your class declaration in if(true) { ... }, which will move your class down a level in scope. Then you should get your two traces before PHP fatal errors.
This should help you find where you class is being included from multiple times in a complex project.
Did You use Zend Framework? I have the same problem too.
I solved it by commenting out this the following line in config/application.ini:
;includePaths.library = APPLICATION_PATH "/../library"
I hope this will help you.
Another possible culprit is source control and unresolved conflicts. SVN may cause the same class to appear twice in the conflicted code file; two alternative versions of it ("mine" and "theirs").
I have encountered that same problem:
newer php version doesn't deal the same with multiple incluse of the same file (as a library), so now I have to change all my include by some include_once.
Or this tricks could help, if you d'ont have too much class in your library...
if( class_exists('TestClass') != true )
{
//your definition of TestClass
}
I had the same problem "PHP Fatal error: Cannot redeclare class XYZ.php".
I have two directories like controller and model and I uploaded by mistakenly XYZ.php in both directories.(so file with the same name cause the issue).
First solution:
Find in your whole project and make sure you have only one class XYZ.php.
Second solution:
Add a namespace in your class so you can use the same class name.
It actually means that class is already declared in the page and you are trying to recreate it.
A simple technique is as follow.
I solved the issue with the following. Hope this will help you a bit.
if(!class_exists("testClassIfExist"))
{
require_once("testClassIfExist.php");
}
i have encountered that same problem. found out the case was the class name. i dealt with it by changing the name. hence resolving the problem.
You must use require_once() function.
I have trying to solve the error : Fatal error: Cannot redeclare class
I have been looking everywhere and I can't find where the class was instantiated.
Is there anyway I can print debug info about the existing instance of that class.
Chances are you are importing the file that declares the class more than once. This can be symptomatic of includes/requires getting out of control so you may need to simply your structure.
One alternative approach is to use autoload to load classes to avoid this kind of problem. Another is to only use include_once or require_once. I generally prefer to use require with a simple structure.
Yes, stupid php doesn't tell you where the class was declared. Try the following (immediately before fatal error line)
$r = new ReflectionClass("YourClassName"); echo $r->getStartLine();
You can find out, where an object was instantiated by using var_dump(debug_backtrace()); and looking at the call stack.
Does anyone know what can cause this problem?
PHP Fatal error: Cannot redeclare class
You have a class of the same name declared more than once. Maybe via multiple includes. When including other files you need to use something like
include_once "something.php";
to prevent multiple inclusions. It's very easy for this to happen, though not always obvious, since you could have a long chain of files being included by one another.
It means you've already created a class.
For instance:
class Foo {}
// some code here
class Foo {}
That second Foo would throw the error.
That happens when you declare a class more than once in a page.
You can fix it by either wrapping that class with an if statement (like below), or you can put it into a separate file and use require_once(), instead of include().
if (!class_exists('TestClass')) {
// Put class TestClass here
}
Use include_once(); - with this, your codes will be included only one time.
This will happen if we use any of the in built classes in the php library. I used the class name as Directory and I got the same error. If you get error first make sure that the class name you use is not one of the in built classes.
This error might also occur if you define the __construct method more than once.
Sometimes that happens due to some bugs in PHP's FastCGI.
Try to restart it. At Ubuntu it's:
service php-fastcgi restart
I had the same problem while using autoload like follows:
<?php
function __autoload($class_name)
{
include $class_name . '.php';
}
__autoload("MyClass1");
$obj = new MyClass1();
?>
and in other class there was:
namespace testClassNamespace;
class MyClass1
{
function __construct()
{
echo "MyClass1 constructor";
}
}
The sollution is to keep namespace compatibility, in my example namespace testClassNamespace; in both files.
Just adding;
This error can also occur if you by mistake put a function inside another function.
PHP 5.3 (an I think older versions too) seems to have problem with same name in different cases. So I had this problem when a had the class Login and the interface it implements LogIn. After I renamed LogIn to Log_In the problem got solved.
Just do one thing whenever you include or require filename namely class.login.php. You can include it this way:
include_once class.login.php or
require_once class.login.php
This way it never throws an error.
This function will print a stack telling you where it was called from:
function PrintTrace() {
$trace = debug_backtrace();
echo '<pre>';
$sb = array();
foreach($trace as $item) {
if(isset($item['file'])) {
$sb[] = htmlspecialchars("$item[file]:$item[line]");
} else {
$sb[] = htmlspecialchars("$item[class]:$item[function]");
}
}
echo implode("\n",$sb);
echo '</pre>';
}
Call this function at the top of the file that includes your class.
Sometimes it will only print once, even though your class is being included two or more times. This is because PHP actually parses all the top-level classes in a file before executing any code and throws the fatal error immediately. To remedy this, wrap your class declaration in if(true) { ... }, which will move your class down a level in scope. Then you should get your two traces before PHP fatal errors.
This should help you find where you class is being included from multiple times in a complex project.
Did You use Zend Framework? I have the same problem too.
I solved it by commenting out this the following line in config/application.ini:
;includePaths.library = APPLICATION_PATH "/../library"
I hope this will help you.
Another possible culprit is source control and unresolved conflicts. SVN may cause the same class to appear twice in the conflicted code file; two alternative versions of it ("mine" and "theirs").
I have encountered that same problem:
newer php version doesn't deal the same with multiple incluse of the same file (as a library), so now I have to change all my include by some include_once.
Or this tricks could help, if you d'ont have too much class in your library...
if( class_exists('TestClass') != true )
{
//your definition of TestClass
}
I had the same problem "PHP Fatal error: Cannot redeclare class XYZ.php".
I have two directories like controller and model and I uploaded by mistakenly XYZ.php in both directories.(so file with the same name cause the issue).
First solution:
Find in your whole project and make sure you have only one class XYZ.php.
Second solution:
Add a namespace in your class so you can use the same class name.
It actually means that class is already declared in the page and you are trying to recreate it.
A simple technique is as follow.
I solved the issue with the following. Hope this will help you a bit.
if(!class_exists("testClassIfExist"))
{
require_once("testClassIfExist.php");
}
i have encountered that same problem. found out the case was the class name. i dealt with it by changing the name. hence resolving the problem.
You must use require_once() function.