java回調機制(同步回調)
場景:父親問姐姐:弟弟的作業寫好了嗎?
姐姐就去問弟弟:弟弟,你作業寫好了嗎?
弟弟寫完作業後,告訴姐姐:姐姐,我作業寫完了!
姐姐知道後,就告訴父親:父親,弟弟作業寫完了!
代碼:
CallBack.java傳遞消息的接口:
package myInterfaceCallback;
public interface CallBack {
public void tell(String result);
}
Brother.java弟弟類:
package myInterfaceCallback;
import myInterfaceCallback.CallBack;
public class Brother {
public void doHomework(CallBack tellSister, String question) {
System.out.println(question);
tellSister.tell("弟弟:姐姐,我已經寫完了!");
}
}
Sister.java姐姐類:
package myInterfaceCallback;
public class Sister implements CallBack{
public Brother brother;
public Sister(Brother brother) {
super();
this.brother = brother;
}
@Override
public void tell(String result) {
// TODO Auto-generated method stub
System.out.println(result);
}
public void toAskBrother(CallBack tellParent, String question) {
// TODO Auto-generated method stub
brother.doHomework(Sister.this, question);
tellParent.tell("姐姐:父親,弟弟作業寫完了!");
}
}
Parent.java父親類:
package myInterfaceCallback;
public class Parent implements CallBack{
public Sister sister;
public Parent(Sister sister) {
super();
this.sister = sister;
}
@Override
public void tell(String result) {
// TODO Auto-generated method stub
System.out.println(result);
}
public void askToSister(String question) {
// TODO Auto-generated method stub
System.out.println(question);
sister.toAskBrother(Parent.this, "姐姐:弟弟,你作業做好了嗎?");
}
}
Test.java測試運行類:
package myInterfaceCallback;
public class Test {
public static void main(String[] args) {
// TODO Auto-generated method stub
Parent parent = new Parent(new Sister(new Brother()));
parent.askToSister("父親:弟弟作業做好了嗎?");
}
}
運行結果:
父親:弟弟作業做好了嗎?
姐姐:弟弟,你作業做好了嗎?
弟弟:姐姐,我已經寫完了!
姐姐:父親,弟弟作業寫完了!
java回調機制(同步回調)