????1. ?????y??
????Java?械???????????????????????纾�??????Comparable<T>??????澹�
????public interface Comparable<T> {
????int compareTo(T o);
????}
????Comparable<T>????卸????????compareTo????????????????????????????????????????Arrays.sort?????????People??????????斜??????People?????????”?????”????People????????Comparable<T>??????????????????????卸????????????????????????????????????????????????????????????????????????????????People?????????????????????????
????public class People implements Comparable<People> {
????...
????public int compareTo(People p) {
????//????????????
????}
????...
????}
??????????Arrays.sort??????????????????????????????Comparable????????????????????????????compareTo????????????????????????????小????????????????????????????????????????????????People???卸??????compareTo?????????????People???????????????????????Comparable<T>???????????????????????锟�??????????????????????????People????????peoples???斜???
????Arrays.sort(peoples);
??????sort?????????????????????????????????????????People????
????if (peoples[i].compareTo(peoples[j]) > 0) {
????//???true???peoples[i] ????peoples[j]
????}
????????Arrays.sort?????????????People?????compareTo?????????????????????People????????????????????????People????????Comparable????????????屑????????????????????????????????????????????????械??????????????????????????????????????????????????????????Date????Job?????????????????????蔚???????????compareTo???????????????????????????????????校???????????????????????????
??????????????????????????????People???????"implements Comparable<People>“??????????????”??????????????????????compareTo?????????眉????????????????“??????????????锌????????????Comparable<T>???????????????????????????compareTo????????????????????????????娣�????????????????????????????????????婕�??????????????????????????Comparable<T>???????????小??????People???????????????????????小?????????????婕�???????????小???????????Compareble<T>???????婕�???????????????????????????????????compareTo????????
????2. ????????
?????????????????????y???????????????????????????????????
??????????????????????畏??????public??protected??????械????蟹??????????public??????????????????畏???????谓???锌?????宄�??????????????????????????????????????y????????????????y??????????????????????????????????霉????implements???????????????????????????????????????卸????????????????????伞?
?????????????娣�???????????????new??????????????????????????????????????????????????????????y???????????????鈥�???
????Comparable<People> p = new People(...);
?????????????????????????????instanceof???卸???????????????????????
????if (p instanceof Comparable) {
????...
????}
?????????????”???“???????
????public interface InA extends InB {
????...
????}
??????????????????????????????????????????????????????????????”?????????娣�”????????????????????????胁?????????????????????????????????????????????????“???”???????????“???”??
????3.?????????????
???????????????????????????????????????????谐??????????????????????????????????”????“???????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????”???????????“??????????????????????????????????????????????????????????????????????????????“???”????????????????????????????????People?卸??????write???????????写????????????????????????????????械?????????????????????????????????????????????????????????????????????????????????????“????”??
??????????妫�????????????????????????????????????????????????????????????????????public????????????械?????????public????????????娣�?”???????“??????????????????private??????????????????????谐??????????????????????????????????????????????????????泄婕�?????蟹??????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????魏胃????
????4. ?????????callback??
?????????callback????????????????????????????????????????????????????????貌?????????????纾琂ava??????懈?Timer???????????????????????????????????????????????????Time???????????????????????????????械????????????????Timer???械???????????????????????????????????Timer??????????????????Timer????????????????????????ActionListener?????????????????锟�?
????public interface ActionListener {
????public void actionPerformed(ActionEvent event);
????}
????????????Time???????????????????actionPerformed???????????????????????卸???????????????????????械???????????鈥�???
1 public class TimerTest {
2     public static void main(String[] args) {
3         ActionListener listener = new TimePrinter();
4         Timer t = new Timer(10000?? listener);
5         t.start();
6         System.exit(0);
7     }
8 }
9
10 class TimePrinter implements ActionListener {
11     public void actionPerformed(ActionEvent event) {
12         Date now = new Date();
13         System.out.println("The time is " + now);
14     }
15 }
??????????????校??????10????????TimerPrinter?械?actionPerformed????????????????蔚?????actionPerformed?????????????????????校?????????????TimePrinter????????????ActionListener??????????????Timer?????????????????y?????????????listener?????????????????????