PHP中的异常处理

Question

I have this scenario:

Interface ClassInterface 
{
  public function getContext();
}

Class A implements ClassInterface 
{
  public function getContext()
  {
     return 'CONTEXTA';
  }

  //Called in controller class
  public function Amethod1() 
  {
    try {
       //assuming that Helper is a property of this class
        $this->helper->helperMethod($this);
     } catch(Exception $ex) {
       throw $ex;
     }
  }
}

Class B implements ClassInterface 
{
  public function getContext()
  {
     return 'CONTEXTB';
  }

  //Called in controller class
  public function Bmethod1() 
  {
     try {
       //assuming that Helper is a property of this class
        $this->helper->helperMethod($this);
     } catch(Exception $ex) {
       throw $ex;
     }
  }

}

Class Helper {
 public function helperMethod(ClassInterface $interface) 
 {
   try {
      $this->verifyContext($interface->getContext());
      //dosomething
   } catch(\Exception $ex) {
     throw $ex;
   }

 }

 private function verifyContext($context) {
    if (condition1) {
       throw new \UnexpectedValueException('Invalid context.');
    }

    return true;
 }

}

I want my controller class which calls Amethod1 and Bmethod1 to know the type of exception(s) thrown in the process. Is it advisable to rethrow an exception just like it was presented? Do you think the throw-catch-throw-catch-throw structure reasonable in this case?

Answer 1

Yes, totally reasonable. But: your specific example can be simplified from:

public function Amethod1() 
{
   try {
      //assuming that Helper is a property of this class
      $this->helper->helperMethod($this);
   } catch(Exception $ex) {
      throw $ex;
   }
}

To:

public function Amethod1() 
{

    //assuming that Helper is a property of this class
    $this->helper->helperMethod($this);
}