访问者模式

Author: anxpp

src/com/anxpp/designpattern/visitor/APPOwner.java

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+packagecom.anxpp.designpattern.visitor;
+//具体访问者
+publicclassAPPOwnerimplementsVisitor{
+@Override
+publicvoidvisit(UserVIPuser){
+Stringestimation = user.getEstimation();
+if(estimation.length()>5)
+System.out.println("记录一条有效反馈：" + estimation);
+ }
+@Override
+publicvoidvisit(UserOrdinaryuser){
+Stringestimation = user.getEstimation();
+if(estimation.length()>10)
+System.out.println("记录一条有效反馈：" + estimation);
+ }
+}

src/com/anxpp/designpattern/visitor/Dispatch.java

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+packagecom.anxpp.designpattern.visitor;
+//演示java的静态分派和动态分派
+//结果会输出：Collection
+//所以重载的分派是根据静态类型进行的
+publicclassDispatch{
+voidprint(FatherClassc){
+System.out.print("父类");
+ }
+voidprint(ChildClassc){
+System.out.print("子类");
+ }
+publicstaticvoidmain(Stringargs[]){
+FatherClasschild = newChildClass();
+newDispatch().print(child);
+child.print();
+ }
+}
+classFatherClass{
+voidprint(){
+System.out.println("父类");
+ }
+}
+classChildClassextendsFatherClass{
+voidprint(){
+System.out.print("子类");
+ }
+}

src/com/anxpp/designpattern/visitor/MultiDispatch.java

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+packagecom.anxpp.designpattern.visitor;
+
+publicclassMultiDispatch{
+publicstaticvoidmain(Stringargs[]){
+Fatherchild = newChild();
+child.print();
+newChild().print(newVistor());
+ }
+}
+classFather{
+voidprint(){
+System.out.println("父类");
+ }
+}
+classChildextendsFather{
+voidprint(){
+System.out.print("子类");
+ }
+voidprint(Vistorc){
+c.print(this);
+ }
+}
+classVistor{
+publicvoidprint(Childchild){
+child.print();
+ }
+}

src/com/anxpp/designpattern/visitor/TestUse.java

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+packagecom.anxpp.designpattern.visitor;
+
+importjava.util.ArrayList;
+importjava.util.Iterator;
+
+publicclassTestUse{
+publicstaticvoidmain(Stringargs[]){
+VisitorappOwner = newAPPOwner();
+ArrayList<User> users = newArrayList<User>();
+users.add(newUserOrdinary("普通用户短反馈"));
+users.add(newUserOrdinary("这是一个普通用户的比较长的反馈"));
+users.add(newUserVIP("VIP用户的短反馈"));
+users.add(newUserVIP("VIP用户的比较长的反馈反馈"));
+Iterator<User> iterator = users.iterator();
+while(iterator.hasNext()){
+iterator.next().accept(appOwner);
+ }
+ }
+}

src/com/anxpp/designpattern/visitor/User.java

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+packagecom.anxpp.designpattern.visitor;
+//抽象元素
+publicinterfaceUser{
+voidaccept(Visitorvisitor);
+}

src/com/anxpp/designpattern/visitor/UserOrdinary.java

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+packagecom.anxpp.designpattern.visitor;
+//普通用户，具体元素
+publicclassUserOrdinaryimplementsUser{
+Stringestimation;
+publicUserOrdinary(Stringestimation){
+this.estimation = estimation;
+ }
+@Override
+publicvoidaccept(Visitorvisitor){
+visitor.visit(this);
+ }
+StringgetEstimation(){
+returnestimation;
+ }
+}

src/com/anxpp/designpattern/visitor/UserVIP.java

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+packagecom.anxpp.designpattern.visitor;
+//VIP用户，具体元素
+publicclassUserVIPimplementsUser{
+Stringestimation;
+publicUserVIP(Stringestimation){
+this.estimation = estimation;
+ }
+@Override
+publicvoidaccept(Visitorvisitor){
+visitor.visit(this);
+ }
+StringgetEstimation(){
+returnestimation;
+ }
+}

src/com/anxpp/designpattern/visitor/Visitor.java

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+packagecom.anxpp.designpattern.visitor;
+//抽象访问者
+publicinterfaceVisitor{
+voidvisit(UserVIPuser);
+voidvisit(UserOrdinaryuser);
+}

src/com/anxpp/designpattern/visitor/package-info.java

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+/**
+ * @author Administrator
+ * 访问者模式
+ */
+packagecom.anxpp.designpattern.visitor;