Design Pattern 01 Observer pattern (Java)

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Observer1

1 ImportJava.util.Observer;2 Importjava.util.Observable;3 4 //Student Class (Student) can be observed after inheriting observable5 classStudentextendsobservable{6     //Properties7     PrivateString name;8     Private BooleanIssleep =false;9     Private BooleanIslate =false;Ten     //constructor Function One      PublicStudent () {} A      PublicStudent (String name) { -          This. Name =name; -     } the     //Sleep Behavior -      Public voidsleep () { -SYSTEM.OUT.PRINTLN (name + "is sleeping"); -Issleep =true; + setchanged (); - notifyobservers (); +          A     } at      PublicString toString () { -         returnname; -     } - } - //Teacher Class (Teacher) implements observer interface becomes observer - classTeacherImplementsobserver{ in @Override -      Public voidUpdate (Observable o,object arg) { toSystem.out.println ("Teacher:" +o+ ", wakeup!wakeup!"); +     } - } the //class Teacher (CLASSHEAD) realizes observer interface becomes observer * classClassheadImplementsobserver{ $ @OverridePanax Notoginseng      Public voidUpdate (Observable o,object arg) { -System.out.println ("Classhead:" +o+ ", Cleantheroomafterschool"); the     } + } A  Public classobserverdemo{ the      Public Static voidMain (string[] arguments) { +Student Tom =NewStudent ("Tom"); -Tom.addobserver (Newclasshead ()); $Tom.addobserver (NewTeacher ()); $  -System.out.println ("with" +tom.countobservers () + "Observer in the observation of Tom"); - tom.sleep (); the          -     }Wuyi}

Observer2

ImportJava.util.Map;ImportJava.util.HashMap;ImportJava.util.Observer;Importjava.util.Observable;//Student Class (Student) can be observed after inheriting observableclassStudentextendsobservable{//Properties    PrivateString name; Private BooleanIssleep =false; Private BooleanIslate =false; //constructor Function     PublicStudent () {} PublicStudent (String name) { This. Name =name; }    //Sleep Behavior     Public voidsleep () {System.out.println (name+ "is sleeping"); Issleep=true;        Setchanged (); Notifyobservers ("Sleep"); }    //Late Behavior     Public voidlate () {SYSTEM.OUT.PRINTLN (name+ "was lated"); Islate=true;        Setchanged (); Notifyobservers ("Late"); }     PublicString toString () {returnname; }}//Teacher Class (Teacher) implements observer interface becomes observerclassTeacherImplementsobserver{//parameter arg as key, the response triggered by this parameter is stored in the map as value    Privatemap<string,string> info =NewHashmap<string,string>();  PublicTeacher () {Info.put ("Sleep", ", wakeup!wakeup!"); Info.put ("Late", ", come in."); }    //to add a key-value pair     Public BooleanAddsay (String k,string v) {returnInfo.put (k,v) = =NULL?false:true; } @Override Public voidUpdate (Observable o,object Arg) {String say=Info.get (ARG); if(Say = =NULL){                return; } System.out.println ("Teacher:" +o+say); }}//class Teacher (CLASSHEAD) realizes observer interface becomes observerclassClassheadImplementsobserver{Privatemap<string,string> info =NewHashmap<string,string>();  PublicClasshead () {Info.put ("Sleep", ", Gooutwashbaface"); Info.put ("Late", ", cleantheroom!"); }     Public BooleanAddsay (String k,string v) {returnInfo.put (k,v) = =NULL?false:true; } @Override Public voidUpdate (Observable o,object Arg) {String say=Info.get (ARG); if(Say = =NULL){                return; } System.out.println ("Classhead:" +o+say); }} Public classobserverdemo{ Public Static voidMain (string[] arguments) {Student Tom=NewStudent ("Tom"); Tom.addobserver (Newclasshead ()); Tom.addobserver (NewTeacher ()); System.out.println ("with" +tom.countobservers () + "observers watching Tom");        Tom.sleep ();    Tom.late (); }}

Design Pattern 01 Observer pattern (Java)