Java使用訪問者模式解決公司層級(jí)結(jié)構(gòu)圖問題詳解

package com.demo.structure;
import com.demo.visitor.IVisitor;
/**
 * 抽象員工類
 *
 * @author
 *
 */
public abstract class Staff {
  // 員工號(hào)
  protected String no;
  // 職工名字
  protected String name;
  // 職位
  protected String position;
  // 薪資
  protected float salary;
  // 私有屬性 長(zhǎng)度字符串
  private int length;
  // 構(gòu)造方法
  public Staff(String no, String name, String position, float salary) {
    this.no = no;
    this.name = name;
    this.position = position;
    this.salary = salary;
    // 計(jì)算總字節(jié)長(zhǎng)度
    this.length += (no == null || "".equals(no.trim())) ? 0
        : no.getBytes().length;
    this.length += (name == null || "".equals(name.trim())) ? 0 : name
        .getBytes().length;
    this.length += (position == null || "".equals(position.trim())) ? 0
        : position.getBytes().length;
    this.length += String.valueOf(salary).getBytes().length;
  }
  // 獲得用戶基本信息
  public void printUserBaseInfo() {
    System.out.println("-|" + this.no + " " + this.name + " "
        + this.position + " " + this.salary);
  }
  // 添加員工信息
  public abstract void add(Staff staff);
  // 刪除員工
  public abstract Staff remove(String no);
  // 接收訪問者對(duì)象
  public abstract void accept(IVisitor visitor);
  public String getNo() {
    return no;
  }
  public void setNo(String no) {
    this.no = no;
  }
  public String getName() {
    return name;
  }
  public void setName(String name) {
    this.name = name;
  }
  public String getPosition() {
    return position;
  }
  public void setPosition(String position) {
    this.position = position;
  }
  public float getSalary() {
    return salary;
  }
  public void setSalary(float salary) {
    this.salary = salary;
  }
}

package com.demo.structure;
import java.util.ArrayList;
import com.demo.visitor.IVisitor;
/**
 * 管理人員（手下有其他員工的人）
 *
 * @author
 *
 */
public class Manager extends Staff {
  // 存儲(chǔ)手下員工信息
  private final ArrayList<Staff> arrayList = new ArrayList<Staff>();
  // 構(gòu)造方法
  public Manager(String no, String name, String position, float salary) {
    super(no, name, position, salary);
  }
  /**
   * 增加一個(gè)員工
   */
  @Override
  public void add(Staff staff) {
    this.arrayList.add(staff);
  }
  /**
   * 刪除員工信息
   */
  @Override
  public Staff remove(String no) {
    Staff staff = null;
    if (no != null && !"".equals(no.trim())) {
      for (int i = 0; i < this.arrayList.size(); i++) {
        if (this.arrayList.get(i) == null) {
          continue;
        }
        if (no.equals(this.arrayList.get(i).getNo())) {
          staff = this.arrayList.remove(i);
          break;
        }
      }
    }
    return staff;
  }
  // 接收訪問者對(duì)象
  @Override
  public void accept(IVisitor visitor) {
    // 訪問自身
    visitor.visit(this);
    // 遍歷list列表中的各個(gè)元素對(duì)象，接收訪問者對(duì)象
    for (int i = 0; i < this.arrayList.size(); i++) {
      if (this.arrayList.get(i) == null) {
        continue;
      }
      // 接收訪問者對(duì)象
      this.arrayList.get(i).accept(visitor);
    }
  }
}

package com.demo.structure;
import com.demo.visitor.IVisitor;
/**
 * 普通員工（真正干活的人）
 *
 * @author
 *
 */
public class Employees extends Staff
{
  // 構(gòu)造方法
  public Employees(String no, String name, String position, float salary)
  {
    super(no, name, position, salary);
  }
  /**
   * 添加員工信息
   */
  @Override
  public void add(Staff staff)
  {
    return;
  }
  /**
   * 刪除員工信息
   */
  @Override
  public Staff remove(String no)
  {
    // 直接返回null
    return null;
  }
  // 接收訪問者對(duì)象
  public void accept(IVisitor visitor)
  {
    visitor.visit(this);
  }
}

package com.demo.visitor;
import com.demo.structure.Employees;
import com.demo.structure.Manager;
/**
 * 訪問者接口
 *
 * @author
 *
 */
public interface IVisitor {
  // 訪問管理者
  public void visit(Manager manager);
  // 訪問普通員工
  public void visit(Employees employees);
}

package com.demo.visitor;
import com.demo.structure.Employees;
import com.demo.structure.Manager;
/**
 * 打印基本信息訪問者
 *
 * @author
 *
 */
public class PrintBaseInfoVisitor implements IVisitor {
  /**
   * 訪問管理者對(duì)象
   */
  public void visit(Manager manager) {
    System.out.print("- 管理者：");
    manager.printUserBaseInfo();
  }
  /**
   * 訪問普通員工對(duì)象
   */
  public void visit(Employees employees) {
    System.out.print("- 一般員工：");
    employees.printUserBaseInfo();
  }
}

package com.demo.visitor;
/**
 * 計(jì)算薪資訪問者
 *
 * @author
 *
 */
public interface ISalaryVisitor extends IVisitor {
  // 統(tǒng)計(jì)管理者薪資情況
  public void printManagerTotalSalary();
  // 統(tǒng)計(jì)一般員工薪資情況
  public void printEmployeesTotalSalary();
  // 統(tǒng)計(jì)所有員工薪資情況
  public void printTotalSalary();
}

package com.demo.visitor;
import com.demo.structure.Employees;
import com.demo.structure.Manager;
/**
 * 計(jì)算薪資訪問者具體實(shí)現(xiàn)
 *
 * @author
 *
 */
public class SalaryVisitor implements ISalaryVisitor {
  // 管理者薪資總和
  private float managerSalary;
  // 普通員工薪資總和
  private float employeesSalary;
  public SalaryVisitor() {
    managerSalary = 0;
    employeesSalary = 0;
  }
  // 訪問管理者
  public void visit(Manager manager) {
    managerSalary += manager.getSalary();
  }
  // 訪問普通員工
  public void visit(Employees employees) {
    employeesSalary += employees.getSalary();
  }
  // 統(tǒng)計(jì)一般員工薪資情況
  public void printEmployeesTotalSalary() {
    System.out.println("一般員工薪資總和：" + employeesSalary);
  }
  // 統(tǒng)計(jì)管理者薪資情況
  public void printManagerTotalSalary() {
    System.out.println("管理者薪資總和：" + managerSalary);
  }
  // 統(tǒng)計(jì)所有員工薪資情況
  public void printTotalSalary() {
    System.out.println("員工薪資總和：" + (managerSalary + employeesSalary));
  }
}

package com.demo;
import com.demo.structure.Employees;
import com.demo.structure.Manager;
import com.demo.structure.Staff;
import com.demo.visitor.PrintBaseInfoVisitor;
import com.demo.visitor.SalaryVisitor;
/**
 * 主應(yīng)用程序
 *
 * @author
 *
 */
public class Client {
  /**
   * @param args
   */
  public static void main(String[] args) {
    // 公司CEO
    Staff boss = new Manager("1", "大老板", "CEO", 100000);
    /**
     * CEO手下有若干部門經(jīng)理
     */
    // 財(cái)務(wù)部經(jīng)理
    Staff financeManager = new Manager("11", "張總", "財(cái)務(wù)部經(jīng)理", 60000);
    // 人事部經(jīng)理
    Staff personnelManager = new Manager("12", "王總", "人事部經(jīng)理", 60000);
    // 技術(shù)部經(jīng)理
    Staff technicalManager = new Manager("13", "陳總", "技術(shù)部經(jīng)理", 60000);
    /**
     * 技術(shù)部門還有助理和若干主管
     */
    // 技術(shù)部門助理
    Staff deptAssistant = new Manager("1301", "王助理", "部門助理", 20000);
    // 技術(shù)部門主管1
    Staff deptManager1 = new Manager("1302", "主管1", "技術(shù)主管", 30000);
    /**
     * 技術(shù)主管deptManager1 下面還有軟件工程師（最終干活的人）
     */
    Staff softwareEngineer1 = new Employees("1302001", "張三", "軟件工程師", 5000);
    Staff softwareEngineer2 = new Employees("1302002", "李四", "軟件工程師", 5500);
    Staff softwareEngineer3 = new Employees("1302003", "王五", "軟件工程師", 4500);
    // 為技術(shù)主管1添加員工信息
    deptManager1.add(softwareEngineer1);
    deptManager1.add(softwareEngineer2);
    deptManager1.add(softwareEngineer3);
    // 技術(shù)部門主管2
    Staff deptManager2 = new Manager("1303", "主管2", "技術(shù)主管", 30000);
    // 為技術(shù)部經(jīng)理 添加：部門助理、技術(shù)主管1和技術(shù)主管2
    technicalManager.add(deptAssistant);
    technicalManager.add(deptManager1);
    technicalManager.add(deptManager2);
    // 市場(chǎng)部經(jīng)理
    Staff marketingManager = new Manager("14", "吳總", "市場(chǎng)部經(jīng)理", 60000);
    // 為CEO 添加：財(cái)務(wù)部經(jīng)理、人事部經(jīng)理、技術(shù)部經(jīng)理和市場(chǎng)部經(jīng)理
    boss.add(financeManager);
    boss.add(personnelManager);
    boss.add(technicalManager);
    boss.add(marketingManager);
    // 打印CEO 信息
    // boss.printUserBaseInfo();
    // 打印CEO 手下員工信息
    boss.accept(new PrintBaseInfoVisitor());
    /**
     * 統(tǒng)計(jì)員工薪資情況
     */
    // 創(chuàng)建統(tǒng)計(jì)員工薪資訪問者
    SalaryVisitor visitor = new SalaryVisitor();
    // 讓大老板接受該訪問者
    boss.accept(visitor);
    // 管理者薪資統(tǒng)計(jì)情況
    visitor.printManagerTotalSalary();
    // 一般員工薪資統(tǒng)計(jì)情況
    visitor.printEmployeesTotalSalary();
    // 所有員工薪資統(tǒng)計(jì)情況
    visitor.printTotalSalary();
  }
}