DynamicCache< K, T > Class Template Reference

An LRU cache implementation in which cache objects are deleted when they are removed from the cache. More...

#include <DynamicCache.h++>

Inheritance diagram for DynamicCache< K, T >:

Collaboration diagram for DynamicCache< K, T >:

Public Member Functions
	DynamicCache (uint_t maxSize)
	Construct a new DynamicCache with the given maximum size. More...
virtual	~DynamicCache ()
	Destructor. More...
void	put (K key, T *item)
	Put an item in the cache. More...
virtual T *	get (const K &key)
	Look up an item in the cache. More...
T *	take (const K &key)
	Remove an item from the cache, and return the item. More...
bool	remove (const K &key)
	Remove an item from the cache. More...
T *	operator[] (const K &key)
	Index operator. More...
bool	contains (const K &key) const
	Test if the cache contains an item with the specified key. More...
virtual void	clear ()
	Remove all items from the cache. More...
uint_t	getMaxSize () const
	Return the maximum size of the cache, i.e., the maximum number of items that the cache can hold. More...
uint_t	getSize () const
	Return the current size of the cache, i.e., the number of items in the cache. More...
bool	isEmpty () const
	Test if the cache is empty. More...
bool	isFull () const
	Test if the cache is full. More...

Protected Member Functions
virtual T *	loadItem (const K &key)
	Called by get() when the cache does not contain an item with the requested key. More...
virtual void	onRemove (const K &key, T *item)
	A method that is called whenever an item is being removed from the cache, but just before it has been deleted. More...

Detailed Description

template<typename K, typename T>
class ccxx::DynamicCache< K, T >

An LRU cache implementation in which cache objects are deleted when they are removed from the cache.

For an implementation that recycles existing objects, see StaticCache.

The cache maintains a key/value map, and takes ownership of its items. If the cache is at full capacity when a new item is inserted, the least recently accessed item is removed to make room.

Whenever an item is removed from the cache as a result of a call to clear() remove(), put(), or the destructor, the onRemove() method is called just before the item is deleted.

Author

Mark Lindner

Constructor & Destructor Documentation

DynamicCache()

DynamicCache

(

uint_t

maxSize

)

Construct a new DynamicCache with the given maximum size.

Parameters

maxSize

The maximum number of items that the cache will hold. If 0, the value 1 will be used instead.

~DynamicCache()

virtual ~DynamicCache ( )

virtual

Destructor.

Clears the cache.

Member Function Documentation

clear()

virtual void clear ( )

virtualinherited

Remove all items from the cache.

Reimplemented in StaticCache< K, T >.

contains()

bool contains ( const K &  key ) const

inherited

Test if the cache contains an item with the specified key.

Parameters

key

The key.

Returns

true the cache contains an item with the specified key, false otherwise.

get()

virtual T* get ( const K &  key )

virtual

Look up an item in the cache.

If the cache does not contain an item with the given key, loadItem() is called to load the item from the external data source.

Parameters

key	The item key.

Returns

The item associated with the key, or NULL if no item with the specified key was found (and could not be loaded).

Implements AbstractCache< K, T >.

getMaxSize()

uint_t getMaxSize ( ) const

inlineinherited

Return the maximum size of the cache, i.e., the maximum number of items that the cache can hold.

getSize()

uint_t getSize ( ) const

inlineinherited

Return the current size of the cache, i.e., the number of items in the cache.

isEmpty()

bool isEmpty ( ) const

inlineinherited

Test if the cache is empty.

isFull()

bool isFull ( ) const

inlineinherited

Test if the cache is full.

loadItem()

virtual T* loadItem ( const K &  key )

protectedvirtual

Called by get() when the cache does not contain an item with the requested key.

Subclasses may override this method to load the item from an external data source. The default implementation is a no-op which returns NULL.

Parameters

key	The key for the item to load.

Returns

The loaded item, or NULL if the item could not be loaded. The cache takes ownership of the item.

onRemove()

virtual void onRemove ( const K &  key, T *  item  )

protectedvirtualinherited

A method that is called whenever an item is being removed from the cache, but just before it has been deleted.

The default implementation is a no-op. Subclasses may override this method to do any necessary cleanup of the item before it is deleted, but should not delete the item itself.

Parameters

key	The key for the item being removed.
item	The item being removed.

operator[]()

T* operator[] ( const K &  key )

inlineinherited

Index operator.

Equivalent to get().

put()

void put	(	K	key,
		T *	item
	)

Put an item in the cache.

Takes ownership of the item.

Parameters

key	The key.
item	The item.

remove()

bool remove

(

const K &

key

)

Remove an item from the cache.

Parameters

key	The item key.

Returns

true if an item was removed, false if no item with the specified key was found.

take()

T* take

(

const K &

key

)

Remove an item from the cache, and return the item.

The onRemove() method is not called.

Parameters

key

The key.

Returns

The item associated with the key, or NULL if no item with the specified key was found.

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The documentation for this class was generated from the following file:

• DynamicCache.h++