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1. 定义
php.net 上的定义 The SplObjectStorage class provides a map from objects to data or, by ignoring data, an object set. This dual purpose can be useful in many cases involving the need to uniquely identify objects. 翻译:SplObjectStorage 类提供从对象到数据映射功能，或者，通过忽视数据来提供对象集合，在很多涉及需要唯一对象的许多情况下，这两点是十分有用的。
2. 接口说明
class SplObjectStorage implements Countable, Iterator, Serializable, ArrayAccess {
// 省略，下边详细解释以及翻译
}
此类实现了 Countable, Iterator, Serializable, ArrayAccess 四个接口，分别对应统计，迭代，序列化和数组访问，四个接口分别说明如下
2.1 Countable
此接口中只有一方法 count()，看 SplObjectStorage 类中此方法的说明（源码位置在 php.jar/stubs/SPL/SPL_c1.php 文件的 1979 行，可以用 phpstorm 按住 command 鼠标左键跳转过去）
/**
* Returns the number of objects in the storage // 返回存储中的对象数量
* @link https://php.net/manual/en/splobjectstorage.count.php
* @return int The number of objects in the storage.
* @since 5.1.0
*/
public function count () {}
翻译注释:Returns the number of objects in the storage // 返回存储中的对象数量
2.2 Iterator
接口注释 Interface for external iterators or objects that can be iterated 的翻译为外部迭代器或可以迭代的对象的接口，此接口中有 5 个方法分别如下 (对应注释中有翻译)
/**
* Rewind the iterator to the first storage element // 将迭代器回到第一个存储的元素
* @link https://php.net/manual/en/splobjectstorage.rewind.php
* @return void
* @since 5.1.0
*/
public function rewind () {}
/**
* Returns if the current iterator entry is valid // 返回当前迭代器条目是否有效
* @link https://php.net/manual/en/splobjectstorage.valid.php
* @return bool true if the iterator entry is valid, false otherwise.
* @since 5.1.0
*/
public function valid () {}
/**
* Returns the index at which the iterator currently is// 返回当前迭代对应的索引
* @link https://php.net/manual/en/splobjectstorage.key.php
* @return int The index corresponding to the position of the iterator.
* @since 5.1.0
*/
public function key () {}
/**
* Returns the current storage entry // 返回当前存储的条目
* @link https://php.net/manual/en/splobjectstorage.current.php
* @return object The object at the current iterator position.
* @since 5.1.0
*/
public function current () {}
/**
* Move to the next entry // 移到下一个条目
* @link https://php.net/manual/en/splobjectstorage.next.php
* @return void
* @since 5.1.0
*/
public function next () {}
2.3 Serializable
接口注释 Interface for customized serializing. 的翻译为用于自定义序列化的接口，此接口中有 2 个方法分别如下 (对应注释中有翻译)
/**
* Serializes the storage // 序列化存储
* @link https://php.net/manual/en/splobjectstorage.serialize.php
* @return string A string representing the storage. // 返回表示存储的字符串
* @since 5.2.2
*/
public function serialize () {}
/**
* Unserializes a storage from its string representation // 从一个字符串表示中对存储反序列化
* @link https://php.net/manual/en/splobjectstorage.unserialize.php
* @param string $serialized <p>
* The serialized representation of a storage.
* </p>
* @return void
* @since 5.2.2
*/
public function unserialize ($serialized) {}
2.4 ArrayAccess
接口注释 Interface to provide accessing objects as arrays. 的翻译为提供像访问数组一样访问对象的接口，此接口中有 4 个方法分别如下 (对应注释中有翻译)
/**
* Checks whether an object exists in the storage // 检查存储中是否存在找个对象
* @link https://php.net/manual/en/splobjectstorage.offsetexists.php
* @param object $object <p>
* The object to look for.
* </p>
* @return bool true if the object exists in the storage,
* and false otherwise.
* @since 5.3.0
*/
public function offsetExists ($object) {}
/**
* Associates data to an object in the storage // 给存储中的对象赋值
* @link https://php.net/manual/en/splobjectstorage.offsetset.php
* @param object $object <p>
* The object to associate data with.
* </p>
* @param mixed $data [optional] <p>
* The data to associate with the object.
* </p>
* @return void
* @since 5.3.0
*/
public function offsetSet ($object, $data = null) {}
/**
* Removes an object from the storage // 从存储中删除一个对象
* @link https://php.net/manual/en/splobjectstorage.offsetunset.php
* @param object $object <p>
* The object to remove.
* </p>
* @return void
* @since 5.3.0
*/
public function offsetUnset ($object) {}
/**
* Returns the data associated with an <type>object</type> // 从存储中获得一个对象
* @link https://php.net/manual/en/splobjectstorage.offsetget.php
* @param object $object <p>
* The object to look for.
* </p>
* @return mixed The data previously associated with the object in the storage.
* @since 5.3.0
*/
public function offsetGet ($object) {}
此接口的功能用代码简单说明如下
$collection = new Supor\Collection();// 假设有一 Collection 类，并且已经实现了 ArrayAccess 接口
$collection[‘a’] = 10;// 我们可以像给数组赋值一样给此对象赋值
var_dump($collection[‘a’]);// 也可以使用取数组值的方法取得对象的属性 而不用 ‘->’
// 输出 int(10)
3. 方法说明
在每个方法的注释中有对应翻译，来说明这个方法的作用
/**
* Adds an object in the storage // 向存储中添加一个对象
* @link https://php.net/manual/en/splobjectstorage.attach.php
* @param object $object <p>
* The object to add.
* </p>
* @param mixed $data [optional] <p>
* The data to associate with the object.
* </p>
* @return void
* @since 5.1.0
*/
public function attach ($object, $data = null) {}
/**
* Removes an object from the storage // 从存储中删除一个对象
* @link https://php.net/manual/en/splobjectstorage.detach.php
* @param object $object <p>
* The object to remove.
* </p>
* @return void
* @since 5.1.0
*/
public function detach ($object) {}
/**
* Checks if the storage contains a specific object // 检查存储中是否包含特定的对象
* @link https://php.net/manual/en/splobjectstorage.contains.php
* @param object $object <p>
* The object to look for.
* </p>
* @return bool true if the object is in the storage, false otherwise.
* @since 5.1.0
*/
public function contains ($object) {}
/**
* Adds all objects from another storage // 添加一个存储中所有对象
* @link https://php.net/manual/en/splobjectstorage.addall.php
* @param SplObjectStorage $storage <p>
* The storage you want to import.
* </p>
* @return void
* @since 5.3.0
*/
public function addAll ($storage) {}
/**
* Removes objects contained in another storage from the current storage // 从当前存储中删除另一个存储中包含的对象
* @link https://php.net/manual/en/splobjectstorage.removeall.php
* @param SplObjectStorage $storage <p>
* The storage containing the elements to remove.
* </p>
* @return void
* @since 5.3.0
*/
public function removeAll ($storage) {}
/**
* 从当前存储中删除另一个存储中不包含的对象
* Removes all objects except for those contained in another storage from the current storage
* @link https://php.net/manual/en/splobjectstorage.removeallexcept.php
* @param SplObjectStorage $storage <p>
* The storage containing the elements to retain in the current storage.
* </p>
* @return void
* @since 5.3.6
*/
public function removeAllExcept ($storage) {}
/**
* Returns the data associated with the current iterator entry // 返回当前迭代器条目相关的数据
* @link https://php.net/manual/en/splobjectstorage.getinfo.php
* @return mixed The data associated with the current iterator position.
* @since 5.3.0
*/
public function getInfo () {}
/**
* Sets the data associated with the current iterator entry// 设置当前迭代器条目相关的数据
* @link https://php.net/manual/en/splobjectstorage.setinfo.php
* @param mixed $data <p>
* The data to associate with the current iterator entry.
* </p>
* @return void
* @since 5.3.0
*/
public function setInfo ($data) {}
/**
* Calculate a unique identifier for the contained objects // 给包含的对象计算一个唯一 ID
* @link https://php.net/manual/en/splobjectstorage.gethash.php
* @param $object <p>
* object whose identifier is to be calculated.
* @return string A string with the calculated identifier.
* @since 5.4.0
*/
public function getHash($object) {}
4. 使用
SplObjectStorage 的对象操作
// 假设有三个 Collection 对象
$collection1 = new Supor\Collection([‘a’ => ‘aa’, ‘b’ => ‘bb’]);
$collection2 = new Supor\Collection([‘c’ => ‘cc’, ‘d’ => ‘dd’]);
$collection3 = new Supor\Collection([‘e’ => ‘ee’, ‘f’ => ‘ff’]);
$splStorage = new SplObjectStorage();
$splStorage->attach($collection1);
// 传入相同的对象会被替代
$splStorage->attach($collection1);
$splStorage->attach($collection2);
$splStorage->attach($collection3);
// 统计 $splStorage 中有多少个对象
$count = $splStorage->count();
var_dump($count);
// 得到某一对象的哈希值
$hash1 = $splStorage->getHash($collection1);
var_dump($hash1);
// 检查存储中是否包含 $collection3
$contains3 = $splStorage->contains($collection3);
var_dump($contains3);
// 将指针后移
$splStorage->next();
// 读取移动后的 key
$key = $splStorage->key();
var_dump($key);
// 删除某个对象
$splStorage->detach($collection3);
// 统计删除后的数量
$count = $splStorage->count();
var_dump($count);
// 遍历 $splStorage 所有对象
// 遍历前先重置一下指针
$splStorage->rewind();
// 当当前迭代器条目返回真时
while ($splStorage->valid()) {
// 打印当前条目
var_dump($splStorage->current());
// 指针后移
$splStorage->next();
}
代码执行结果如下: