Use of keyword instanceof

[darek9576]

Can anyone outline the use of the keyword "instanceof".
I mean, when do we use it etc..

Couple of examples would make it clearer i guess..

[uniflare]

wellif its anything like php, its a conditional operator such as == etc.

eg,

if(SomeSpecificClass instaceof SomeSpecificClassorInterface){
// You knw this class either extends somespecificclass or implements somespecificinterface.
}

Mainly used to make sure modular code aheres to the overall program design. (OOP, MVC etc)

[Webuser]

it is quite useful if we use objects. the most remarkable example is swing mouse clicking listener like a

public void mouseClicked(MouseEvent e)
{
  if(e.getComponent() instanceof JButton){return;}
}

as a rule it is much useful if you cannot predict what object is to be chosen by user etc... something like an object ensurance :cool:

[Niekfct]

Say you have a method, needing a parameter of an instance of the "MyObject" object.
Then, we have 2 objects, extending the MyObject: YourObject and OurObject. If you want to do different things when receiving a MyObject you can do this as follows:

public void myMethod(MyObject mo)
{
    if(mo instanceof YourObject){
       //do some stuff.
    }else if(mo instanceof OurObject){
       //do some other stuff.
    }else{
       //mo is an instance of MyObject, no extension.
    }
}