设计模式

sjms/src/main/java/com/quinn/sjms/visitor/Element.java

@@ -0,0 +1,10 @@
+package com.quinn.sjms.visitor;
+
+public abstract class Element {
+
+    //定义业务逻辑
+    public abstract void doSomething();
+    //允许谁来访问
+    public abstract void accept(IVisitor visitor);
+
+}

sjms/src/main/java/com/quinn/sjms/visitor/ElementImpl.java

@@ -0,0 +1,13 @@
+package com.quinn.sjms.visitor;
+
+public class ElementImpl extends Element {
+    @Override
+    public void doSomething() {
+        System.out.println("干饭");
+    }
+
+    @Override
+    public void accept(IVisitor visitor) {
+        visitor.visit(this);
+    }
+}

sjms/src/main/java/com/quinn/sjms/visitor/ElementStructure.java

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+package com.quinn.sjms.visitor;
+
+public class ElementStructure {
+
+    public static Element createElement(){
+        return new ElementImpl();
+    }
+
+}

sjms/src/main/java/com/quinn/sjms/visitor/IVisitor.java

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+package com.quinn.sjms.visitor;
+
+/**
+ * 抽象类或者接口，声明访问者可以访问哪些元素，具体到程序中就是visit方法的参数定
+ * 义哪些对象是可以被访问的。
+ */
+public interface IVisitor {
+
+    //可以访问哪些对象
+    void visit(ElementImpl el1);
+
+}

sjms/src/main/java/com/quinn/sjms/visitor/Visitor.java

@@ -0,0 +1,8 @@
+package com.quinn.sjms.visitor;
+
+public class Visitor implements IVisitor {
+    @Override
+    public void visit(ElementImpl el1) {
+        el1.doSomething();
+    }
+}

sjms/src/main/java/com/quinn/sjms/visitor/VisitorClient.java

@@ -0,0 +1,11 @@
+package com.quinn.sjms.visitor;
+
+public class VisitorClient {
+
+    public static void main(String[] args) {
+        Element element = ElementStructure.createElement();
+        Visitor visitor = new Visitor();
+        element.accept(visitor);
+    }
+
+}