she1
asked on
•Servlet Callback method ??
•why we say that the followings are Servlet Callback method ?
–doGet
–doPost
–Init
–Destroy
why we use the word "callback".
thanks
–doGet
–doPost
–Init
–Destroy
why we use the word "callback".
thanks
as RK says, a callback method is designed to be called asynchronously. That is, if object A owns method callback(), and object A enlists object B to perform some work, object B may later call a.callback() with the result of the work. Object A does not need to maintain a reference to B for this to happen.
doGet and doPost are callbacks because any HTTP client can call them any time. Init() and destroy() are callbacks because the container can call them anytime if it wishes to start and stop the servlet. Actually doGet and doPost are really called by the container as well (in reaction to the client's HTTP request). But they still can be called any time.
doGet and doPost are callbacks because any HTTP client can call them any time. Init() and destroy() are callbacks because the container can call them anytime if it wishes to start and stop the servlet. Actually doGet and doPost are really called by the container as well (in reaction to the client's HTTP request). But they still can be called any time.
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A callback method is a method intended to be passed as a parameter. The callee can then call the passed method asynchronously and with whatever parameters it deems appropriate. Callbacks are often used in event handling code.
R.K