ExpiryCache< Key, T > Class Template Reference

Template class for a cache that removes items as soon as it exceeds maximum capacity. It uses shared pointers, so items will only be physically deleted once they go out of scope.

#include <Rendering/OpenGL/expirycache.h>

Inheritance diagram for ExpiryCache< Key, T >:

Public Types
typedef T	ItemType
using	PtrType = QSharedPointer< T >
using	WeakPtrType = QWeakPointer< T >

Public Member Functions
	ExpiryCache (int capacity=100)
virtual	~ExpiryCache ()
int	capacity () const
void	clear ()
bool	contains (const Key &key) const
int	count () const
bool	insert (const Key &key, const PtrType &item, int cost=0)
bool	isEmpty () const
PtrType	object (const Key &key) const
PtrType	operator[] (const Key &key) const
void	setCapacity (int capacity)
int	size () const
PtrType	take (const Key &key)
int	totalCost () const

Member Typedef Documentation

ItemType

typedef T ItemType

PtrType

using PtrType = QSharedPointer<T>

WeakPtrType

using WeakPtrType = QWeakPointer<T>

Constructor & Destructor Documentation

ExpiryCache()

ExpiryCache

(

int

capacity = 100

)

Create a cache with the specified size limit.

~ExpiryCache()

~ExpiryCache

virtual

We ensure the cache is empty, but we don't bother checking whether all of the items are deleted - they will clean themselves up eventually.

Member Function Documentation

capacity()

int capacity

clear()

void clear

contains()

bool contains

(

const Key &

key

)

const

Parameters

key	The key used to find the object in the cache.

Returns

true if the cache contains the object, false otherwise.

count()

int count

insert()

bool insert	(	const Key &	key,
		const PtrType &	item,
		int	cost = 0
	)

Parameters

key	The key to associated with the object in the cache.
item	The item to be stored in the cache.
cost	The cost associated with the item in the cache.

Note

The cache does not allow duplicate keys. If an item is inserted with a key that is still in use (i.e. a valid pointer to its associated object still remains - in the cache or otherwise),

Returns

True if the item could be inserted, false otherwise.

isEmpty()

bool isEmpty

object()

ExpiryCache< Key, T >::PtrType object

(

const Key &

key

)

const

Parameters

key	The key used to find the object in the cache.

Returns

Attempts to retrieve an item from the cache. If the item doesn't exist in the cache, an invalid pointer is returned. Callers should always test for isNull() on the returned pointer.

operator[]()

ExpiryCache< Key, T >::PtrType operator[]

(

const Key &

key

)

const

setCapacity()

void setCapacity

(

int

capacity

)

Parameters

capacity

The maximum size of the cache.

Sets the capacity of the cache; the size after which items will be deleted.

size()

int size

take()

ExpiryCache< Key, T >::PtrType take

(

const Key &

key

)

Parameters

key	The key used to find the object in the cache.

Returns

Takes an item out of the cache (removes it), returning it to the user in a pointer. Once the last pointer goes out of scope, the item will be deleted, as it is no inter held by the cache.

totalCost()

int totalCost