状态模式

// 请假系统

class LeaveRequesModel {
private $user = null; //请假人
private $beginDate = null; //请假开始时间
private $leaveDays = 0; //请假天数
private $result; //审核结果

public function setUser(string $user = '') {
$this->user = $user;
}

public function getUser() {
return $this->user;
}

public function setBeginDate(string $begin_date = '') {
$this->beginDate = $begin_date;
}

public function getBeginDate() {
return $this->beginDate;
}

public function setLeaveDays(int $leave_days = 0) {
$this->leaveDays = $leave_days;
}

public function getLeaveDays() {
return $this->leaveDays;
}

public function setResult(string $result) {
$this->result = $result;
}

public function getResult() {
return $this->result;
}

}

interface State {
public function doWork(StateMachine $ctx);
}

abstract class StateMachine {

//持有一个状态对象
protected $state; // State
protected $businessVO = null;

abstract function doWork();

public function getBusinessVO() {
return $this->businessVO;
}

public function setBusinessVO($vo) {
$this->businessVO = $vo;
}

public function getState() {
return $this->state;
}

public function setState($state){
$this->state = $state;
}

}

//请假流程的状态接口
interface LeaveRequestState extends State
{
//这里可以扩展跟自己流程相关的处理
}

//****************************************上下文环境类********************
//处理客户端请求的上下文（相当于Context角色）
class LeaveRequesContext extends StateMachine
{

public function doWork()
{
$this->state->doWork($this);
}

}

class AuditOverState implements LeaveRequestState {

public function doWork(StateMachine $ctx) {
$vo = $ctx->getBusinessVO();

if( !($vo instanceof LeaveRequesModel)) {
throw new \Exception('状态类不对');
}

echo $vo->getUser() . "，你的请假申请己经审核结束，结果是：" . $vo->getResult() . PHP_EOL;
}

}

//项目经理审核的状态类
class ProjectManagerState implements LeaveRequestState {

private $auditOverState;
private $depState;

public function __construct() {
$this->auditOverState = new AuditOverState();
$this->depState = new DepManagerState();
}

public function doWork(StateMachine $ctx) {
$vo = $ctx->getBusinessVO();

if( !($vo instanceof LeaveRequesModel)) {
throw new \Exception('状态类不对');
}

echo "项目经理审核中，请稍候..." . PHP_EOL;
echo $vo->getUser() . "，申请从 " . $vo->getBeginDate() . "开始请假，请假 " . $vo->getLeaveDays() . " 天，请部门经理审核（1为同意，2为不同意）" . PHP_EOL;

//读取控制台输入的数据
$a = 1;
$result = ($a == 1) ? "同意" : "不同意";
$vo->setResult("项目经理审核结果：" . $result);

//根据选择的结果和条件来设置一下步
if ($a == 1)
{
if($vo->getLeaveDays() > 3)
{
//如果请假天数大于3天，而且项目经理同意了，就提交
//给部门经理。
$ctx->setState($this->depState);
$ctx->doWork(); //继续执行下一步工作

}
else
{
//请假在3天以内的，由项目经理做主，转向审核结束状态
$ctx->setState($this->auditOverState);
$ctx->doWork();
}
}
else
{
//由项目经理不同意，转向审核结束状态
$ctx->setState($this->auditOverState);
$ctx->doWork();
}
}

public function __destruct() {
$this->auditOverState = null;
$this->depState = null;
}
}

//部门经理审核的状态类
class DepManagerState implements LeaveRequestState {

private $auditOverState;

public function __construct() {
$this->auditOverState = new AuditOverState();
}

public function doWork(StateMachine $ctx) {
$vo = $ctx->getBusinessVO();

if( !($vo instanceof LeaveRequesModel)) {
throw new \Exception('状态类不对');
}

echo "部门经理审核中，请稍候..." . PHP_EOL;
echo $vo->getUser() . "，申请从 " . $vo->getBeginDate() . "开始请假，请假 " . $vo->getLeaveDays() . " 天，请部门经理审核（1为同意，2为不同意）" . PHP_EOL;

//读取控制台输入的数据 这里写成固定的
$a = 1;
$result = ($a == 1) ? "同意" : "不同意";
$vo->setResult("部门经理审核结果：" . $result);

//由项目经理审核以后，转向审核结束状态
$ctx->setState($this->auditOverState);
$ctx->doWork();
}

public function __destruct() {
$this->auditOverState = null;
}
}

//创建业务对象，并设置业务数据
$lrm = new LeaveRequesModel();
$lrm->setUser("小李");
$lrm->setBeginDate("2017-12-25");
$lrm->setLeaveDays(5);

//创建上下文对象
$ctx = new LeaveRequesContext();

//为上下文对象设置业务数据对象
$ctx->setBusinessVO($lrm);

$pms = new ProjectManagerState();
$ctx->setState($pms); //向项目经理请假