?php

//pthreads v3引入了Threaded對(duì)象自動(dòng)不變性的概念
//如果成員被設(shè)置成Threaded對(duì)象，那么它將不能被再次改寫(xiě)
//當(dāng)然，這主要還是為了性能優(yōu)化，但有時(shí)我們又需要改寫(xiě)成員，那么就需要繼承自Volatile類(lèi)了
class Task extends Thread
{
  private $data;
  private $result;

  public function __construct()
  {
    $this->data = 'abc';
    var_dump($this->data);

    //成員設(shè)置成標(biāo)量，是可以再次被改寫(xiě)的
    $this->data = 'def';
    var_dump($this->data);

    //這里給data設(shè)置為數(shù)組時(shí)，會(huì)自動(dòng)轉(zhuǎn)換成Volatile對(duì)象
    $this->data = [1, 2, 3];
    var_dump($this->data);

    //這個(gè)時(shí)候再給data賦值時(shí)，就會(huì)報(bào)錯(cuò)了
    //成員被設(shè)置成Threaded對(duì)象時(shí)(Volatile繼承自Threaded)，該成員就不能再次被改寫(xiě)了
    $this->data = [4, 5, 6];
    var_dump($this->data);

    //當(dāng)然，我們可以顯式的強(qiáng)制轉(zhuǎn)換，不讓Threaded幫我自動(dòng)轉(zhuǎn)成Volatile對(duì)象
    $this->result = (array)[1, 2, 3];
    //打印出來(lái)是數(shù)組
    var_dump($this->result);
    $this->result = (array)[4, 5, 6];
    //成員賦值成功
    var_dump($this->result);
  }
}

new Task();

?php

//Volatile類(lèi)允許其成員可更改
class Task extends Volatile
{
  private $data;

  public function __construct()
  {
    //繼承自Volatile類(lèi)后，我們的成員在設(shè)置成Threaded對(duì)象后，仍可改寫(xiě)
    $this->data = [
      'a' => 123,
      'b' => 456,
      'c' => 789,
    ];
    var_dump($this->data);

    //這里成員數(shù)據(jù)成功被改寫(xiě)
    $this->data = [
      'a' => 'aaa',
      'b' => 'bbb',
      'c' => 'ccc',
    ];
    var_dump($this->data);

    //由于Threaded對(duì)象實(shí)現(xiàn)了ArrayAccess接口，我們可以像訪問(wèn)數(shù)組一樣，訪問(wèn)Volatile對(duì)象
    echo $this->data['a'], "\t", $this->data['b'], "\t", $this->data['c'], "\n";

    foreach ($this->data as $item) {
      echo $item, "\n";
    }
  }
}

new Task();