Himself A little knowledge on the design model, see today in the project code it in writing, the purpose is to make the lower class B, turn head to access to the members of the upper class A, is there anyone who know what is this model?

 
# include & lt; Iostream> 

using namespace std; 

The class BListener {
Public: 
Virtual ~ BListener () {} 
Virtual void listener ()=0; 
}; 

Class B {
Public: 
BListener * m_listener; 

B (BListener * listener=NULL) {
M_listener=listener; 
} 
Void foo () {//need to access member variables in A 
If (m_listener) {
M_listener - & gt; Listener (); 
} 
} 
}; 

Class A: public BListener {
Public: 
Void onNotify () {
//access A member variable 
} 
Void the listener () {
OnNotify (); 
} 
Public: 
B B; 
}; 

Int main () {
A, A. 

return 0; 
} 

CodePudding user response:

Should be the decorator pattern

CodePudding user response:

Listener model, example is actually button controls such as event model,

CodePudding user response:

Saw the decorator pattern, it should not be
The listener pattern is a little like, are not wholly
But I feel this code or practical
Is A first class A, has existed for many years, the member variables have A lot of, the business logic is more complex, this time if we get another new function, need to achieve in A, if you continue to add member variables and methods, A will make A more and more heavy, this question should be A common problem, especially the old code
So they implemented A B to complete the function of trigger flows or in A namely hold B object, call A member of the B method, and B want to change A certain members of the variables, that is to say, A and B is each other, to be called A, B, B to invoke A, this time can be done in this way, A very few changes to the code, the main new code implementation in B, but A and B are also free to call