NullCacheItemPool::clear()   A
last analyzed

Complexity

Conditions 1
Paths 1

Size

Total Lines 4
Code Lines 2

Duplication

Lines 0
Ratio 0 %

Importance

Changes 1
Bugs 0 Features 0
Metric Value
c 1
b 0
f 0
dl 0
loc 4
rs 10
cc 1
eloc 2
nc 1
nop 0
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<?php
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/**
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 *
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 * PHP version 5.5
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 *
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 * @package Psr\Cache
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 * @author  Sergey V.Kuzin <[email protected]>
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 * @license MIT
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 */
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namespace Psr\Cache;
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class NullCacheItemPool implements CacheItemPoolInterface
0 ignored issues
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Bug introduced by
There is at least one abstract method in this class. Maybe declare it as abstract, or implement the remaining methods: deleteItem, hasItem
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{
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    /**
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     * Returns a Cache Item representing the specified key.
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     *
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     * This method must always return an ItemInterface object, even in case of
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     * a cache miss. It MUST NOT return null.
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     *
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     * @param string $key
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     *   The key for which to return the corresponding Cache Item.
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     * @return \Psr\Cache\CacheItemInterface
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     *   The corresponding Cache Item.
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     * @throws \Psr\Cache\InvalidArgumentException
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     *   If the $key string is not a legal value a \Psr\Cache\InvalidArgumentException
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     *   MUST be thrown.
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     */
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    public function getItem($key)
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    {
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        return new NullCacheItem($key);
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    }
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    /**
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     * Returns a traversable set of cache items.
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     *
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     * @param array $keys
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     * An indexed array of keys of items to retrieve.
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     * @return array|\Traversable
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     * A traversable collection of Cache Items keyed by the cache keys of
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     * each item. A Cache item will be returned for each key, even if that
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     * key is not found. However, if no keys are specified then an empty
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     * traversable MUST be returned instead.
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     */
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    public function getItems(array $keys = array())
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    {
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        // TODO: Implement getItems() method.
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    }
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    /**
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     * Deletes all items in the pool.
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     *
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     * @return boolean
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     *   True if the pool was successfully cleared. False if there was an error.
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     */
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    public function clear()
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    {
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        return true;
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    }
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    /**
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     * Removes multiple items from the pool.
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     *
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     * @param array $keys
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     * An array of keys that should be removed from the pool.
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     * @return static
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     * The invoked object.
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     */
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    public function deleteItems(array $keys)
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    {
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        return $this;
0 ignored issues
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Bug Best Practice introduced by
The return type of return $this; (Psr\Cache\NullCacheItemPool) is incompatible with the return type declared by the interface Psr\Cache\CacheItemPoolInterface::deleteItems of type boolean.

If you return a value from a function or method, it should be a sub-type of the type that is given by the parent type f.e. an interface, or abstract method. This is more formally defined by the Lizkov substitution principle, and guarantees that classes that depend on the parent type can use any instance of a child type interchangably. This principle also belongs to the SOLID principles for object oriented design.

Let’s take a look at an example:

class Author {
    private $name;

    public function __construct($name) {
        $this->name = $name;
    }

    public function getName() {
        return $this->name;
    }
}

abstract class Post {
    public function getAuthor() {
        return 'Johannes';
    }
}

class BlogPost extends Post {
    public function getAuthor() {
        return new Author('Johannes');
    }
}

class ForumPost extends Post { /* ... */ }

function my_function(Post $post) {
    echo strtoupper($post->getAuthor());
}

Our function my_function expects a Post object, and outputs the author of the post. The base class Post returns a simple string and outputting a simple string will work just fine. However, the child class BlogPost which is a sub-type of Post instead decided to return an object, and is therefore violating the SOLID principles. If a BlogPost were passed to my_function, PHP would not complain, but ultimately fail when executing the strtoupper call in its body.

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    }
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    /**
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     * Persists a cache item immediately.
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     *
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     * @param CacheItemInterface $item
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     *   The cache item to save.
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     *
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     * @return static
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     *   The invoked object.
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     */
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    public function save(CacheItemInterface $item)
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    {
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        return $this;
0 ignored issues
show
Bug Best Practice introduced by
The return type of return $this; (Psr\Cache\NullCacheItemPool) is incompatible with the return type declared by the interface Psr\Cache\CacheItemPoolInterface::save of type boolean.

If you return a value from a function or method, it should be a sub-type of the type that is given by the parent type f.e. an interface, or abstract method. This is more formally defined by the Lizkov substitution principle, and guarantees that classes that depend on the parent type can use any instance of a child type interchangably. This principle also belongs to the SOLID principles for object oriented design.

Let’s take a look at an example:

class Author {
    private $name;

    public function __construct($name) {
        $this->name = $name;
    }

    public function getName() {
        return $this->name;
    }
}

abstract class Post {
    public function getAuthor() {
        return 'Johannes';
    }
}

class BlogPost extends Post {
    public function getAuthor() {
        return new Author('Johannes');
    }
}

class ForumPost extends Post { /* ... */ }

function my_function(Post $post) {
    echo strtoupper($post->getAuthor());
}

Our function my_function expects a Post object, and outputs the author of the post. The base class Post returns a simple string and outputting a simple string will work just fine. However, the child class BlogPost which is a sub-type of Post instead decided to return an object, and is therefore violating the SOLID principles. If a BlogPost were passed to my_function, PHP would not complain, but ultimately fail when executing the strtoupper call in its body.

Loading history...
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    }
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    /**
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     * Sets a cache item to be persisted later.
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     *
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     * @param CacheItemInterface $item
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     *   The cache item to save.
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     * @return static
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     *   The invoked object.
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     */
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    public function saveDeferred(CacheItemInterface $item)
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    {
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        return $this;
0 ignored issues
show
Bug Best Practice introduced by
The return type of return $this; (Psr\Cache\NullCacheItemPool) is incompatible with the return type declared by the interface Psr\Cache\CacheItemPoolInterface::saveDeferred of type boolean.

If you return a value from a function or method, it should be a sub-type of the type that is given by the parent type f.e. an interface, or abstract method. This is more formally defined by the Lizkov substitution principle, and guarantees that classes that depend on the parent type can use any instance of a child type interchangably. This principle also belongs to the SOLID principles for object oriented design.

Let’s take a look at an example:

class Author {
    private $name;

    public function __construct($name) {
        $this->name = $name;
    }

    public function getName() {
        return $this->name;
    }
}

abstract class Post {
    public function getAuthor() {
        return 'Johannes';
    }
}

class BlogPost extends Post {
    public function getAuthor() {
        return new Author('Johannes');
    }
}

class ForumPost extends Post { /* ... */ }

function my_function(Post $post) {
    echo strtoupper($post->getAuthor());
}

Our function my_function expects a Post object, and outputs the author of the post. The base class Post returns a simple string and outputting a simple string will work just fine. However, the child class BlogPost which is a sub-type of Post instead decided to return an object, and is therefore violating the SOLID principles. If a BlogPost were passed to my_function, PHP would not complain, but ultimately fail when executing the strtoupper call in its body.

Loading history...
99
    }
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    /**
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     * Persists any deferred cache items.
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     *
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     * @return bool
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     *   TRUE if all not-yet-saved items were successfully saved. FALSE otherwise.
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     */
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    public function commit()
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    {
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        return true;
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    }
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}
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