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。

___FCKpd___0___FCKpd___1

// 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 " ";
___FCKpd___2原文名：Practical Php Patterns: Iterator        作者：Giorgio

补充：Web开发 , php ,