PHP 之 SplObjectStorage物件儲存

摘要： 1. 定義 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 u...

1. 定義

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類提供從物件到資料對映功能，或者，通過忽視資料來提供物件集合，在很多涉及需要唯一物件的許多情況下，這兩點是十分有用的。

2. 介面說明

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

此類實現了 Countable, Iterator, Serializable, ArrayAccess 四個介面，分別對應統計，迭代，序列化和陣列訪問，四個介面分別說明如下

2.1 Countable

此介面中只有一方法 count() ，看 SplObjectStorage 類中此方法的說明（原始碼位置在 php.jar/stubs/SPL/SPL_c1.php檔案的1979行 ，可以用phpstorm按住command滑鼠左鍵跳轉過去）

/**
 * Returns the number of objects in the storage //返回儲存中的物件數量
 * @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 () {}

翻譯註釋:Returns the number of objects in the storage //返回儲存中的物件數量

2.2 Iterator

介面註釋 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物件的介面 ，此介面中有5個方法分別如下(對應註釋中有翻譯)

/**
 * Rewind the iterator to the first storage element //將迭代器回到第一個儲存的元素
 * @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//返回當前迭代對應的索引
 * @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 //返回當前儲存的條目
 * @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 //移到下一個條目
 * @link https://php.net/manual/en/splobjectstorage.next.php
 * @return void 
 * @since 5.1.0
 */
public function next () {}

2.3 Serializable

介面註釋 Interface for customized serializing. 的翻譯為 用於自定義序列化的介面 ，此介面中有2個方法分別如下(對應註釋中有翻譯)

/**
 * Serializes the storage //序列化儲存
 * @link https://php.net/manual/en/splobjectstorage.serialize.php
 * @return string A string representing the storage. //返回表示儲存的字串
 * @since 5.2.2
 */
public function serialize () {}
/**
 * Unserializes a storage from its string representation //從一個字串表示中對儲存反序列化
 * @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

介面註釋 Interface to provide accessing objects as arrays. 的翻譯為 提供像訪問陣列一樣訪問物件的介面 ，此介面中有4個方法分別如下(對應註釋中有翻譯)

/**
 * Checks whether an object exists in the storage //檢查儲存中是否存在找個物件
 * @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 //給儲存中的物件賦值
 * @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 //從儲存中刪除一個物件
 * @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> //從儲存中獲得一個物件
 * @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) {}

此介面的功能用程式碼簡單說明如下

$collection = new Supor\Collection();//假設有一Collection類，並且已經實現了ArrayAccess 介面
$collection['a'] = 10;//我們可以像給陣列賦值一樣給此物件賦值
var_dump($collection['a']);//也可以使用取陣列值的方法取得物件的屬性 而不用 '->'
//輸出 int(10)

3. 方法說明

在每個方法的註釋中有對應翻譯，來說明這個方法的作用

/**
 * Adds an object in the storage //向儲存中新增一個物件
 * @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 //從儲存中刪除一個物件
 * @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 //檢查儲存中是否包含特定的物件
 * @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 //新增一個儲存中所有物件
 * @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 //從當前儲存中刪除另一個儲存中包含的物件
 * @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) {}

/**
 *從當前儲存中刪除另一個儲存中不包含的物件
 * 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 //返回當前迭代器條目相關的資料
 * @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//設定當前迭代器條目相關的資料
 * @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 //給包含的物件計算一個唯一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的物件操作

//假設有三個Collection物件
$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);
//傳入相同的物件會被替代
$splStorage->attach($collection1);
$splStorage->attach($collection2);
$splStorage->attach($collection3);

//統計$splStorage中有多少個物件
$count = $splStorage->count();
var_dump($count);
//得到某一物件的雜湊值
$hash1 = $splStorage->getHash($collection1);
var_dump($hash1);

//檢查儲存中是否包含$collection3
$contains3 = $splStorage->contains($collection3);
var_dump($contains3);

//將指標後移
$splStorage->next();
//讀取移動後的key
$key = $splStorage->key();
var_dump($key);

//刪除某個物件
$splStorage->detach($collection3);
//統計刪除後的數量
$count = $splStorage->count();
var_dump($count);

//遍歷$splStorage所有物件
//遍歷前先重置一下指標
$splStorage->rewind();
//噹噹前迭代器條目返回真時
while ($splStorage->valid()) {
//列印當前條目
var_dump($splStorage->current());
//指標後移
$splStorage->next();
}

程式碼執行結果如下: