摘要：類實(shí)現(xiàn)了對象存儲映射表，應(yīng)用于需要唯一標(biāo)識多個(gè)對象的存儲場景。在之前僅能存儲對象，之后可以針對每個(gè)對象添加一條對應(yīng)的數(shù)據(jù)。實(shí)際上他們并沒有直接的關(guān)系。

php.net上的定義 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. 翻譯:SplObjectStorage類提供從對象到數(shù)據(jù)映射功能，或者，通過忽視數(shù)據(jù)來提供對象集合，在很多涉及需要唯一對象的許多情況下，這兩點(diǎn)是十分有用的。

SplObjectStorage類實(shí)現(xiàn)了對象存儲映射表，應(yīng)用于需要唯一標(biāo)識多個(gè)對象的存儲場景。 在PHP5.3.0之前僅能存儲對象，之后可以針對每個(gè)對象添加一條對應(yīng)的數(shù)據(jù)。 SplObjectStorage類的數(shù)據(jù)存儲依賴于PHP的HashTable實(shí)現(xiàn)，與傳統(tǒng)的使用數(shù)組和spl_object_hash函數(shù)生成數(shù)組key相比， 其直接使用HashTable的實(shí)現(xiàn)在性能上有較大的優(yōu)勢。 有一些奇怪的是，在PHP手冊中，SplObjectStorage類放在數(shù)據(jù)結(jié)構(gòu)目錄下。 但是他的實(shí)現(xiàn)和觀察者模式的接口放在同一個(gè)文件（ext/spl/spl_observer.c）。 實(shí)際上他們并沒有直接的關(guān)系。《深入理解php內(nèi)核》

class SplObjectStorage implements Countable, Iterator, Serializable, ArrayAccess {
 //省略，下邊詳細(xì)解釋以及翻譯
}

此類實(shí)現(xiàn)了 Countable, Iterator, Serializable, ArrayAccess 四個(gè)接口，分別對應(yīng)統(tǒng)計(jì)，迭代，序列化和數(shù)組訪問，四個(gè)接口分別說明如下

2.1 Countable

此接口中只有一方法count()，看SplObjectStorage 類中此方法的說明（源碼位置在php.jar/stubs/SPL/SPL_c1.php文件的1979行，可以用phpstorm按住command鼠標(biāo)左鍵跳轉(zhuǎn)過去）

/**
 * Returns the number of objects in the storage //返回存儲中的對象數(shù)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 () {}

翻譯注釋:Returns the number of objects in the storage //返回存儲中的對象數(shù)量

2.2 Iterator

接口注釋Interface for external iterators or objects that can be iterated 的翻譯為外部迭代器或可以迭代的對象的接口，此接口中有5個(gè)方法分別如下(對應(yīng)注釋中有翻譯)

/**
 * Rewind the iterator to the first storage element //將迭代器回到第一個(gè)存儲的元素
 * @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 //返回當(dāng)前迭代器條目是否有效
 * @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//返回當(dāng)前迭代對應(yīng)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 //返回當(dāng)前存儲的條目
 * @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 //移到下一個(gè)條目
 * @link https://php.net/manual/en/splobjectstorage.next.php
 * @return void 
 * @since 5.1.0
 */
public function next () {}

2.3 Serializable

接口注釋Interface for customized serializing.的翻譯為用于自定義序列化的接口，此接口中有2個(gè)方法分別如下(對應(yīng)注釋中有翻譯)

/**
 * Serializes the storage //序列化存儲
 * @link https://php.net/manual/en/splobjectstorage.serialize.php
 * @return string A string representing the storage. //返回表示存儲的字符串
 * @since 5.2.2
 */
public function serialize () {}
/**
 * Unserializes a storage from its string representation //從一個(gè)字符串表示中對存儲反序列化
 * @link https://php.net/manual/en/splobjectstorage.unserialize.php
 * @param string $serialized 

 * The serialized representation of a storage.
 * 
 * @return void 
 * @since 5.2.2
 */
public function unserialize ($serialized) {}

2.4 ArrayAccess

接口注釋Interface to provide accessing objects as arrays.的翻譯為提供像訪問數(shù)組一樣訪問對象的接口，此接口中有4個(gè)方法分別如下(對應(yīng)注釋中有翻譯)

/**
 * Checks whether an object exists in the storage //檢查存儲中是否存在找個(gè)對象
 * @link https://php.net/manual/en/splobjectstorage.offsetexists.php
 * @param object $object 

 * The object to look for.
 * 
 * @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 //給存儲中的對象賦值
 * @link https://php.net/manual/en/splobjectstorage.offsetset.php
 * @param object $object 

 * The object to associate data with.
 * 
 * @param mixed $data [optional] 

 * The data to associate with the object.
 * 
 * @return void 
 * @since 5.3.0
 */
public function offsetSet ($object, $data = null) {}

/**
 * Removes an object from the storage //從存儲中刪除一個(gè)對象
 * @link https://php.net/manual/en/splobjectstorage.offsetunset.php
 * @param object $object 

 * The object to remove.
 * 
 * @return void 
 * @since 5.3.0
 */
public function offsetUnset ($object) {}

/**
 * Returns the data associated with an object //從存儲中獲得一個(gè)對象
 * @link https://php.net/manual/en/splobjectstorage.offsetget.php
 * @param object $object 

 * The object to look for.
 * 
 * @return mixed The data previously associated with the object in the storage.
 * @since 5.3.0
 */
public function offsetGet ($object) {}

此接口的功能用代碼簡單說明如下

$collection = new SuporCollection();//假設(shè)有一Collection類，并且已經(jīng)實(shí)現(xiàn)了ArrayAccess 接口
$collection["a"] = 10;//我們可以像給數(shù)組賦值一樣給此對象賦值
var_dump($collection["a"]);//也可以使用取數(shù)組值的方法取得對象的屬性 而不用 "->"
//輸出 int(10)

在每個(gè)方法的注釋中有對應(yīng)翻譯，來說明這個(gè)方法的作用

/**
 * Adds an object in the storage //向存儲中添加一個(gè)對象
 * @link https://php.net/manual/en/splobjectstorage.attach.php
 * @param object $object 

 * The object to add.
 * 
 * @param mixed $data [optional] 

 * The data to associate with the object.
 * 
 * @return void 
 * @since 5.1.0
 */
public function attach ($object, $data = null) {}

/**
 * Removes an object from the storage //從存儲中刪除一個(gè)對象
 * @link https://php.net/manual/en/splobjectstorage.detach.php
 * @param object $object 

 * The object to remove.
 * 
 * @return void 
 * @since 5.1.0
 */
public function detach ($object) {}

/**
 * Checks if the storage contains a specific object //檢查存儲中是否包含特定的對象
 * @link https://php.net/manual/en/splobjectstorage.contains.php
 * @param object $object 

 * The object to look for.
 * 
 * @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 //添加一個(gè)存儲中所有對象
 * @link https://php.net/manual/en/splobjectstorage.addall.php
 * @param SplObjectStorage $storage 

 * The storage you want to import.
 * 
 * @return void 
 * @since 5.3.0
 */
public function addAll ($storage) {}

/**
 * Removes objects contained in another storage from the current storage //從當(dāng)前存儲中刪除另一個(gè)存儲中包含的對象
 * @link https://php.net/manual/en/splobjectstorage.removeall.php
 * @param SplObjectStorage $storage 

 * The storage containing the elements to remove.
 * 
 * @return void 
 * @since 5.3.0
 */
public function removeAll ($storage) {}

/**
 *從當(dāng)前存儲中刪除另一個(gè)存儲中不包含的對象
 * 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 

 * The storage containing the elements to retain in the current storage.
 * 
 * @return void
 * @since 5.3.6
 */
public function removeAllExcept ($storage) {}

/**
 * Returns the data associated with the current iterator entry //返回當(dāng)前迭代器條目相關(guān)的數(shù)據(jù)
 * @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//設(shè)置當(dāng)前迭代器條目相關(guān)的數(shù)據(jù)
 * @link https://php.net/manual/en/splobjectstorage.setinfo.php
 * @param mixed $data 

 * The data to associate with the current iterator entry.
 * 
 * @return void 
 * @since 5.3.0
 */
public function setInfo ($data) {}
/**
 * Calculate a unique identifier for the contained objects //給包含的對象計(jì)算一個(gè)唯一ID
 * @link https://php.net/manual/en/splobjectstorage.gethash.php
 * @param $object  

 * object whose identifier is to be calculated.
 * @return string A string with the calculated identifier.
 * @since 5.4.0
*/
public function getHash($object) {}
        

SplObjectStorage的對象操作

//假設(shè)有三個(gè)Collection對象
$collection1 = new SuporCollection(["a" => "aa", "b" => "bb"]);
$collection2 = new SuporCollection(["c" => "cc", "d" => "dd"]);
$collection3 = new SuporCollection(["e" => "ee", "f" => "ff"]);

$splStorage = new SplObjectStorage();
$splStorage->attach($collection1);
//傳入相同的對象會(huì)被替代
$splStorage->attach($collection1);
$splStorage->attach($collection2);
$splStorage->attach($collection3);

//統(tǒng)計(jì)$splStorage中有多少個(gè)對象
$count = $splStorage->count();
var_dump($count);
//得到某一對象的哈希值
$hash1 = $splStorage->getHash($collection1);
var_dump($hash1);

//檢查存儲中是否包含$collection3
$contains3 = $splStorage->contains($collection3);
var_dump($contains3);

//將指針后移
$splStorage->next();
//讀取移動(dòng)后的key
$key = $splStorage->key();
var_dump($key);

//刪除某個(gè)對象
$splStorage->detach($collection3);
//統(tǒng)計(jì)刪除后的數(shù)量
$count = $splStorage->count();
var_dump($count);

//遍歷$splStorage所有對象
//遍歷前先重置一下指針
$splStorage->rewind();
//當(dāng)當(dāng)前迭代器條目返回真時(shí)
while ($splStorage->valid()) {
    //打印當(dāng)前條目
    var_dump($splStorage->current());
    //指針后移
    $splStorage->next();
}

代碼執(zhí)行結(jié)果如下: