嵌套RecursiveIteraotrs

Question

我想使用RecursiveIterator接口迭代嵌套对象。 HeadHunterEntity对象可以有许多CandidateEntities。我想在主循环中迭代所有CandidateEntities，但是出了点问题。

我有这样的主循环：

$iterator = new RecursiveIteratorIterator(new RecursiveHunterCandidatesIterator(new RecursiveArrayIterator($this->getHeadHunters())));

foreach ($iterator as $object) {
  echo('<br>MAIN LOOP: ' . (is_object($object) ? get_class($object) : $object));
}

RecursiveHunterCandidatesIterator

class RecursiveHunterCandidatesIterator extends RecursiveFilterIterator {

  public function accept() {
    echo "<br>RecursiveHunterCandidatesIterator (accept) hasChildren: "  . $this->hasChildren();

    return $this->hasChildren();
  }

  public function hasChildren() {
    $current = $this->current();    

    echo "<br>RecursiveHunterCandidatesIterator (hasChildren) current Class: "  .  get_class($current);

    return is_object($this->current()) ? (boolean)count($this->current()->getHuntedCandidates()) : FALSE;
  }

  public function getChildren() {
     echo "<br>RecursiveHunterCandidatesIterator (getChildren) count: "  .  count($this->current()->getHuntedCandidates());

     $childIterator =  new RecursiveArrayIterator($this->current()->getHuntedCandidates());
     $childIterator2 =  new RecursiveArrayIterator(array(1,2,3));

     return $childIterator;
  }
}

结果出乎意料，我还没有进入主循环:(

RecursiveHunterCandidatesIterator (hasChildren) current Class: HeadHunterEntity
RecursiveHunterCandidatesIterator (accept) hasChildren: 1
RecursiveHunterCandidatesIterator (hasChildren) current Class: HeadHunterEntity
RecursiveHunterCandidatesIterator (hasChildren) current Class: HeadHunterEntity
RecursiveHunterCandidatesIterator (getChildren) count: 2
RecursiveHunterCandidatesIterator (hasChildren) current Class: HeadHunterEntity
RecursiveHunterCandidatesIterator (accept) hasChildren: 
RecursiveHunterCandidatesIterator (hasChildren) current Class: HeadHunterEntity
RecursiveHunterCandidatesIterator (hasChildren) current Class: HeadHunterEntity
RecursiveHunterCandidatesIterator (accept) hasChildren: 
RecursiveHunterCandidatesIterator (hasChildren) current Class: HeadHunterEntity

但是如果我返回$ childIterator2，那么主循环会产生预期结果：

    RecursiveHunterCandidatesIterator (hasChildren) current Class: HeadHunterEntity
    RecursiveHunterCandidatesIterator (accept) hasChildren: 1
    RecursiveHunterCandidatesIterator (hasChildren) current Class: HeadHunterEntity
    RecursiveHunterCandidatesIterator (hasChildren) current Class: HeadHunterEntity
    RecursiveHunterCandidatesIterator (getChildren) count: 2
    MAIN LOOP: 1
    MAIN LOOP: 2
    MAIN LOOP: 3
    RecursiveHunterCandidatesIterator (hasChildren) current Class: HeadHunterEntity
    RecursiveHunterCandidatesIterator (accept) hasChildren: 
    RecursiveHunterCandidatesIterator (hasChildren) current Class: HeadHunterEntity
    RecursiveHunterCandidatesIterator (hasChildren) current Class: HeadHunterEntity
    RecursiveHunterCandidatesIterator (accept) hasChildren: 
    RecursiveHunterCandidatesIterator (hasChildren) current Class: HeadHunterEntity

$ this-＆gt; current（） - ＆gt; getHuntedCandidates（）返回数组，所以它应该像$ childIterator2中的假1,2,3 aray一样在主循环中...

我做错了什么？

Answer 1

我找到了解决方案。作为RecursiveIterator的getChildren（）方法，必须返回RecursiveIterator的实例，我已经扩展了RecursiveArrayIterator（如果你需要在这个级别上过滤对象，你也可以扩展RecursiveFilterIterator。）

class CandidateIterator extends RecursiveArrayIterator {

   public function hasChildren() { 
     return false; 
   }
}

当然更改了RecursiveHunterCandidatesIterator类中返回的迭代器：

class RecursiveHunterCandidatesIterator extends RecursiveFilterIterator {

    (..)

    public function getChildren() {
         $childIterator =  new CandidateIterator(new RecursiveArrayIterator($this->current()->getHuntedCandidates()));

         return $childIterator;
    }
}