小傅哥 | 重学 Java 设计模式：实战迭代器模式「模拟公司组织架构树结构关系，深度迭代遍历人员信息输出场景」

itstack-demo-design-15-00/pom.xml

+<?xml version="1.0" encoding="UTF-8"?>
+<project xmlns="http://maven.apache.org/POM/4.0.0"
+         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
+    <parent>
+        <artifactId>itstack-demo-design</artifactId>
+        <groupId>org.itstack</groupId>
+        <version>1.0-SNAPSHOT</version>
+    </parent>
+    <modelVersion>4.0.0</modelVersion>
+
+    <artifactId>itstack-demo-design-15-00</artifactId>
+
+
+</project>
\ No newline at end of file

itstack-demo-design-15-00/src/main/java/org/itstack/demo/design/group/Employee.java

+package org.itstack.demo.design.group;
+
+/**
+ * 雇员
+ */
+public class Employee {
+
+    private String uId;   // ID
+    private String name;  // 姓名
+    private String desc;  // 备注
+
+    public Employee(String uId, String name) {
+        this.uId = uId;
+        this.name = name;
+    }
+
+    public Employee(String uId, String name, String desc) {
+        this.uId = uId;
+        this.name = name;
+        this.desc = desc;
+    }
+
+    public String getuId() {
+        return uId;
+    }
+
+    public void setuId(String uId) {
+        this.uId = uId;
+    }
+
+    public String getName() {
+        return name;
+    }
+
+    public void setName(String name) {
+        this.name = name;
+    }
+
+    public String getDesc() {
+        return desc;
+    }
+
+    public void setDesc(String desc) {
+        this.desc = desc;
+    }
+
+}

itstack-demo-design-15-00/src/main/java/org/itstack/demo/design/group/GroupStructure.java

+package org.itstack.demo.design.group;
+
+import org.itstack.demo.design.lang.Collection;
+import org.itstack.demo.design.lang.Iterator;
+
+import java.util.HashMap;
+import java.util.LinkedList;
+import java.util.List;
+import java.util.Map;
+import java.util.concurrent.ConcurrentHashMap;
+
+public class GroupStructure implements Collection<Employee, Link> {
+
+    private String groupId;                                                 // 组织ID，也是一个组织链的头部ID
+    private String groupName;                                               // 组织名称
+    private Map<String, Employee> employeeMap = new ConcurrentHashMap<String, Employee>();  // 雇员列表
+    private Map<String, List<Link>> linkMap = new ConcurrentHashMap<String, List<Link>>();  // 组织架构关系；id->list
+    private Map<String, String> invertedMap = new ConcurrentHashMap<String, String>();       // 反向关系链
+
+    public GroupStructure(String groupId, String groupName) {
+        this.groupId = groupId;
+        this.groupName = groupName;
+    }
+
+    public boolean add(Employee employee) {
+        return null != employeeMap.put(employee.getuId(), employee);
+    }
+
+    public boolean remove(Employee o) {
+        return null != employeeMap.remove(o.getuId());
+    }
+
+    public boolean addLink(String key, Link link) {
+        invertedMap.put(link.getToId(), link.getFromId());
+        if (linkMap.containsKey(key)) {
+            return linkMap.get(key).add(link);
+        } else {
+            List<Link> links = new LinkedList<Link>();
+            links.add(link);
+            linkMap.put(key, links);
+            return true;
+        }
+    }
+
+    public boolean removeLink(String key) {
+        return null != linkMap.remove(key);
+    }
+
+    public Iterator<Employee> iterator() {
+
+        return new Iterator<Employee>() {
+
+            HashMap<String, Integer> keyMap = new HashMap<String, Integer>();
+
+            int totalIdx = 0;
+            private String fromId = groupId;  // 雇员ID，From
+            private String toId = groupId;   // 雇员ID，To
+
+            public boolean hasNext() {
+                return totalIdx < employeeMap.size();
+            }
+
+            public Employee next() {
+                List<Link> links = linkMap.get(toId);
+                int cursorIdx = getCursorIdx(toId);
+
+                // 同级节点扫描
+                if (null == links) {
+                    cursorIdx = getCursorIdx(fromId);
+                    links = linkMap.get(fromId);
+                }
+
+                // 上级节点扫描
+                while (cursorIdx > links.size() - 1) {
+                    fromId = invertedMap.get(fromId);
+                    cursorIdx = getCursorIdx(fromId);
+                    links = linkMap.get(fromId);
+                }
+
+                // 获取节点
+                Link link = links.get(cursorIdx);
+                toId = link.getToId();
+                fromId = link.getFromId();
+                totalIdx++;
+
+                // 返回结果
+                return employeeMap.get(link.getToId());
+            }
+
+            public int getCursorIdx(String key) {
+                int idx = 0;
+                if (keyMap.containsKey(key)) {
+                    idx = keyMap.get(key);
+                    keyMap.put(key, ++idx);
+                } else {
+                    keyMap.put(key, idx);
+                }
+                return idx;
+            }
+        };
+    }
+
+}

itstack-demo-design-15-00/src/main/java/org/itstack/demo/design/group/Link.java

+package org.itstack.demo.design.group;
+
+/**
+ * 树节点链路
+ */
+public class Link {
+
+    private String fromId; // 雇员ID
+    private String toId;   // 雇员ID
+
+    public Link(String fromId, String toId) {
+        this.fromId = fromId;
+        this.toId = toId;
+    }
+
+    public String getFromId() {
+        return fromId;
+    }
+
+    public void setFromId(String fromId) {
+        this.fromId = fromId;
+    }
+
+    public String getToId() {
+        return toId;
+    }
+
+    public void setToId(String toId) {
+        this.toId = toId;
+    }
+    
+}

itstack-demo-design-15-00/src/main/java/org/itstack/demo/design/lang/Collection.java

+package org.itstack.demo.design.lang;
+
+public interface Collection<E, L> extends Iterable<E> {
+
+    boolean add(E e);
+
+    boolean remove(E e);
+
+    boolean addLink(String key, L l);
+
+    boolean removeLink(String key);
+
+    Iterator<E> iterator();
+
+}

itstack-demo-design-15-00/src/main/java/org/itstack/demo/design/lang/Iterable.java

+package org.itstack.demo.design.lang;
+
+public interface Iterable<E> {
+
+    Iterator<E> iterator();
+
+}

itstack-demo-design-15-00/src/main/java/org/itstack/demo/design/lang/Iterator.java

+package org.itstack.demo.design.lang;
+
+public interface Iterator<E> {
+
+    boolean hasNext();
+
+    E next();
+    
+}

itstack-demo-design-15-00/src/test/java/org/itstack/demo/design/test/ApiTest.java

+package org.itstack.demo.design.test;
+
+import com.alibaba.fastjson.JSON;
+import org.apache.commons.lang3.StringUtils;
+import org.itstack.demo.design.group.Employee;
+import org.itstack.demo.design.group.GroupStructure;
+import org.itstack.demo.design.group.Link;
+import org.itstack.demo.design.lang.Iterator;
+import org.junit.Test;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+public class ApiTest {
+
+    private Logger logger = LoggerFactory.getLogger(ApiTest.class);
+
+    @Test
+    public void test_iterator() {
+        GroupStructure groupStructure = new GroupStructure("1", "小傅哥");
+        groupStructure.add(new Employee("2", "花花", "二级部门"));
+        groupStructure.add(new Employee("3", "豆包", "二级部门"));
+        groupStructure.add(new Employee("4", "蹦蹦", "三级部门"));
+        groupStructure.add(new Employee("5", "大烧", "三级部门"));
+        groupStructure.add(new Employee("6", "虎哥", "四级部门"));
+        groupStructure.add(new Employee("7", "玲姐", "四级部门"));
+        groupStructure.add(new Employee("8", "秋雅", "四级部门"));
+
+        groupStructure.addLink("1", new Link("1", "2"));
+        groupStructure.addLink("1", new Link("1", "3"));
+
+        groupStructure.addLink("2", new Link("2", "4"));
+        groupStructure.addLink("2", new Link("2", "5"));
+
+        groupStructure.addLink("5", new Link("5", "6"));
+        groupStructure.addLink("5", new Link("5", "7"));
+        groupStructure.addLink("5", new Link("5", "8"));
+
+        Iterator<Employee> iterator = groupStructure.iterator();
+        while (iterator.hasNext()) {
+            Employee employee = iterator.next();
+            logger.info("{}，雇员 Id：{} Name：{}", employee.getDesc(), employee.getuId(), employee.getName());
+        }
+
+    }
+
+}

pom.xml

@@ -45,6 +45,7 @@
         <module>itstack-demo-design-14-00</module>
         <module>itstack-demo-design-14-01</module>
         <module>itstack-demo-design-14-02</module>
+        <module>itstack-demo-design-15-00</module>
     </modules>
 
     <dependencies>