标签：ack tee 接口 str system div rri 参数传递 abstract
抽象访问者（Visitor）：声明所有访问者需要的接口
具体访问者（ConcreteVisitor）：实现抽象访问者声明的接口
抽象节点元素（Element）：提供一个接口，能够接受访问者作为参数传递给节点元素
具体节点元素（ConcreteElement）：实现抽象节点元素声明的接口
结构对象（ObjectStructure）：提供一个接口，能够访问到所有的节点元素，一般作为一个集合特有节点元素的引用
客户端（Client）：分别创建访问者和节点元素的对象，调用访问者访问变量节点元素
visitor
package design.pattern.visitor; public interface Visitor { public void visit(Element element); }
element
package design.pattern.visitor; public abstract class Element { protected String type; public Element(String type) { this.type = type; } public void accept(Visitor visitor) { visitor.visit(this); } public String getType() { return this.type; } }
objectstructure
package design.pattern.visitor; public class ObjectStructure { private Element arr = new ConcreteElement("ConcreteElement"); private Visitor visitor; public void setVisitor(Visitor visitor) { this.visitor = visitor; } public void print() { if (null == visitor) throw new RuntimeException(); arr.accept(visitor); } }
concreteelement
package design.pattern.visitor; public class ConcreteElement extends Element { public ConcreteElement(String type) { super(type); } }
concretevisitora
package design.pattern.visitor; public class ConcreteVisitorA implements Visitor { @Override public void visit(Element element) { System.out.println("ConcreteVisitorA visit " + element.getType()); } }
concretevisitorb
package design.pattern.visitor; public class ConcreteVisitorB implements Visitor { @Override public void visit(Element element) { System.out.println("ConcreteVisitorB visit " + element.getType()); } }
标签：ack tee 接口 str system div rri 参数传递 abstract
原文地址：http://www.cnblogs.com/m2492565210/p/7231722.html
