| 1: |
What keyword would you use to define a class constant?
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| 2: |
A static property cannot be changed at runtime. True or false?
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| 3: |
Can a static method access normal object properties using the $this pseudo variable?
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| 4: |
What built-in method could you implement to catch an attempt to access a nonexistent property?
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| 5: |
How would you prevent a method being overridden?
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| 6: |
What built-in method will be called when an object is about to be destroyed?
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| 7: |
What keyword would you use to send an exception to client code?
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| 8: |
What clause would you define to handle a specific exception in client code?
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| 9: |
How would you instantiate an abstract class?
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| A1:
| You would define a class constant with the const keyword:
const DJ="John Peel"
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| A2:
| False. A static property can be changed throughout script operation. Statics are properties that are set at class rather than object level. |
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| A3:
| No. Static methods have no direct access to object properties because they do not exist in object context. |
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| A4:
| You can implement the __get() method to catch attempts to read nonexistent properties. |
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| A5:
| You can prevent a method from being overridden by declaring it final:
final function getDJ() {
return "john peel";
}
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| A6:
| The __destruct() method is called when an object is about to be destroyed. |
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| A7:
| You can send an exception to calling code with the throw keyword:
throw new WrongDjException("not John Peel");
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| A8:
| You can handle a specific exception using a catch clause:
try {
getRightDJ();
} catch ( WrongDjException $e ) {
print "Sorry an error occurred";
}
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| A9:
| This is a trick question. You cannot instantiate an abstract class; you must subclass it and instantiate a concrete child class. |
