Pool对象是多个Worker对象的容器，同时也是它们的控制器，对Worker功能更高抽象。

比如Worker是河，而线程是运行在河里的船。Pool则是管理着多条河。

       sql = $sql;    }    public function run() {        $db = $this->worker->getDb();        $res = mysql_query($this->sql, $db);        $tmp = array();        while($row = mysql_fetch_assoc($res)) {            //这里不能使用$this->data[] = $row;这种方式。            $tmp[] = $row;        }        $this->data = $tmp;        //这里工作完后，设置为垃圾        //在Pool::collect中isGarbage()判断时则为真        $this->setGarbage();    }    public function getData() {        return $this->data;    }}class SqlWorker extends Worker {    protected static $db = null;    public function getDb() {        if(!self::$db) {            self::$db = mysql_connect('127.0.0.1', 'root', '');            mysql_select_db('test', self::$db);        }        return self::$db;    }}//这里创建5个Worker对象的Pool线程池$pool = new Pool(5, 'SqlWorker');//我们创建20个Sql线程对象，并提交到Pool的Worker中$sqls = array();for($ix = 0; $ix < 20; ++$ix) {    $sql = new Sql("select * from test order by id limit {$ix},1");    $sqls[] = $sql;    //$pool->submit($sql);不要在这里submit}//注意，这里循环提交$sql//如果把$pool->submit放到前面的for循环内，会出现一个错误//第一个Sql对象的sql语句会跟最后一个相同，导致结果出现问题foreach($sqls as $sql) {    //这里的submit方法有问题，它会修改$sqls    //导致第一个Sql对象与最后一个相同    //不知是不是BUG    $pool->submit($sql);}//等待队列中执行完成$pool->shutdown();$ret = array();foreach($sqls as $sql) {    $ret[] = $sql->getData();}file_put_contents('ret.txt', var_export($ret, true));//回收已完成的对象$pool->collect(function($sql){    return $sql->isGarbage();});

array (  0 =>   array (    0 =>     array (      'id' => '20',      'name' => 'mmm',    ),  ),  1 =>   array (    0 =>     array (      'id' => '2',      'name' => '222',    ),  ),  2 =>   array (    0 =>     array (      'id' => '3',      'name' => '333',    ),  ),  3 =>   array (    0 =>     array (      'id' => '4',      'name' => '444',    ),  ),  4 =>   array (    0 =>     array (      'id' => '5',      'name' => '555',    ),  ),  5 =>   array (    0 =>     array (      'id' => '6',      'name' => '666',    ),  ),  6 =>   array (    0 =>     array (      'id' => '7',      'name' => '777',    ),  ),  7 =>   array (    0 =>     array (      'id' => '8',      'name' => '888',    ),  ),  8 =>   array (    0 =>     array (      'id' => '9',      'name' => '999',    ),  ),  9 =>   array (    0 =>     array (      'id' => '10',      'name' => 'aaa',    ),  ),  10 =>   array (    0 =>     array (      'id' => '11',      'name' => 'bbb',    ),  ),  11 =>   array (    0 =>     array (      'id' => '12',      'name' => 'ccc',    ),  ),  12 =>   array (    0 =>     array (      'id' => '13',      'name' => 'ddd',    ),  ),  13 =>   array (    0 =>     array (      'id' => '14',      'name' => 'eee',    ),  ),  14 =>   array (    0 =>     array (      'id' => '15',      'name' => 'fff',    ),  ),  15 =>   array (    0 =>     array (      'id' => '16',      'name' => 'ggg',    ),  ),  16 =>   array (    0 =>     array (      'id' => '17',      'name' => 'vvv',    ),  ),  17 =>   array (    0 =>     array (      'id' => '18',      'name' => 'hhh',    ),  ),  18 =>   array (    0 =>     array (      'id' => '19',      'name' => 'nnn',    ),  ),  19 =>   array (    0 =>     array (      'id' => '20',      'name' => 'mmm',    ),  ),)

从结果可以看出，第一条记录跟最后一条是相同的，再没有pool->submit之前$sqls数组中的对象都是正确的，submit之后第一个对象的数据就改变了，不知道是不是pthreads的BUG。

 

上述代码我们通过创建一个包含5个SqlWorker对象的pool，然后创建20个Sql对象加入到pool中。

 

当然我们的Sql类并不一定非要继承自Collectable类，我们也可自定义判断什么时候可回收。

       name = $name;    }    public function run() {        $this->data = "{$this->name} run... in thread [" . $this->worker->getName() . "] \r\n";        //通过do来判断是否完成        //如果为true，则让Pool::collect回收        $this->do = true;    }    public function isDo() {         return  $this->do;    }    public function getData() {        return $this->data;    }}class MyWorker extends Worker {    public static $name = 0;    public function __construct() {        self::$name++;    }    public function run() {            }    public function getName() {        return self::$name;    }}$pool = new Pool(5, 'MyWorker');$works = array();for($ix = 0; $ix < 20; ++$ix) {    $work = new MyWork($ix);    $works[] = $work;}foreach($works as $work) {    $pool->submit($work);}$pool->shutdown();foreach($works as $work) {    echo $work->getData();}//回收已完成的对象$pool->collect(function($work){    //我们通过自定义函数isDo来判断对象是否执行完毕    return $work->isDo();});

执行结果如下：

19 run... in thread [5]1 run... in thread [2]2 run... in thread [3]3 run... in thread [4]4 run... in thread [5]5 run... in thread [1]6 run... in thread [2]7 run... in thread [3]8 run... in thread [4]9 run... in thread [5]10 run... in thread [1]11 run... in thread [2]12 run... in thread [3]13 run... in thread [4]14 run... in thread [5]15 run... in thread [1]16 run... in thread [2]17 run... in thread [3]18 run... in thread [4]19 run... in thread [5]

第一条记录为什么会有问题，前面我已经说过了。这里我们看20个MyWork对象，它们顺序的加入到5个MyWorker对象中，如果第一条记录没有问题的话，它们分别加入到1，2，3，4，5的MyWorker中，然后远行run方法。