PHP设计模式漫谈之迭代器模式(5)

注意，迭代器是比对象集更好的抽象，因为我们可以让InfiniteIterators，NoRewindIterators等，不用与普通数组阵列与一致，因此，Iterator缺少count()函数等功能。
在PHP官方手册中可以找到完整的SPL迭代器列表。得益于对PHP的强力支持，使用迭代器模式的大部分工作都包括在标准实现中，下面的代码示例就利用了标准Iterator和RecursiveIterators的功能。

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// lets play with RecursiveIterator implementations $it = new RecursiveArrayIterator(array( A, B, array( C, D ), array( array( E, F ), array( G, H, I ) ) )); // $it is a RecursiveIterator but also an Iterator, // so it loops normally over the four elements // of the array. echo "Foreach over a RecursiveIterator: "; foreach ($it as $value) { echo $value; // but RecursiveIterators specify additional // methods to explore children nodes $children = $it->hasChildren() ? {Yes} : {No}; echo $children, ; } echo " "; // we can bridge it to a different contract via // a RecursiveIteratorIterator, whose cryptic name // should be read as an Iterator that spans over // a RecursiveIterator. echo "Foreach over a RecursiveIteratorIterator: "; foreach (new RecursiveIteratorIterator($it) as $value) { echo $value; } echo " "; 原文名：Practical Php Patterns: Iterator 作者：Giorgio

content;
private $_index = 0;

public function __construct(array $content)
{
$this->_content = $content;
}

public function rewind()
{
$this->_index = 0;
}

public function valid()
{
return isset($this->_content[$this->_index]);
}

public function current()
{
return $this->_content[$this->_index];
}

public function key()
{
return $this->_index;
}

public function next()
{
$this->_index++;
}
}

$arrayarray = array(A, B, C, D);
echo "Collection: ";
foreach (new Collection($array) as $key => $value) {
echo "$key => $value. ";
}
echo " ";
___FCKpd___1___FCKpd___2原文名：Practical Php Patterns: Iterator 作者：Giorgio

content;

public function __construct(array $content)
{
$this->_content = $content;
}

public function contains($number)
{
return in_array($number, $this->_content);
}

/**
* Only this method is necessary to implement IteratorAggregate.
* @return Iterator
*/
public function getIterator()
{
return new ArrayIterator($this->_content);
}
}

echo "NumbersSet: ";
foreach (new NumbersSet($array) as $key => $value) {
echo "$key => $value. ";
}
echo " ";
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content;
private $_index = 0;

public function __construct(array $content)
{
$this->_content = $content;
}

public function rewind()
{
$this->_index = 0;
}

public function valid()
{
return isset($this->_content[$this->_index]);
}

public function current()
{
return $this->_content[$this->_index];
}

public function key()
{
return $this->_index;
}

public function next()
{
$this->_index++;
}
}

$arrayarray = array(A, B, C, D);
echo "Collection: ";
foreach (new Collection($array) as $key => $value) {
echo "$key => $value. ";
}
echo " ";
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