ngap::MemoryCache< VALUE > Class Template Reference

A simple memory cache. More...

#include <MemoryCache.h>

Inheritance diagram for ngap::MemoryCache< VALUE >:

Collaboration diagram for ngap::MemoryCache< VALUE >:

Public Member Functions
virtual void	clear ()
	Clear the cache.
virtual bool	get (const std::string &key, VALUE &value)
	Get the item from the cache. If the item is not in the cache, the value-result parameter is not modified.
virtual bool	initialize (int max_items, int purge_items)
	Initialize the cache.
	MemoryCache (const MemoryCache *src)=delete
MemoryCache &	operator= (const MemoryCache *src)=delete
virtual void	put (const std::string &key, const VALUE &value)
	Put the item in the cache. If the key is already in the cache, the value is updated.
virtual unsigned long	size () const
	How many items are in the cache.

Friends
class	MemoryCacheTest

Detailed Description

template<typename VALUE>
class ngap::MemoryCache< VALUE >

A simple memory cache.

This is a header-only class. It is used by NgapRequestHandler to cache string values. It could be tested more completely and used in other places.

The cache implements a simple FIFO queue to purge the oldest entries when the cache is full. Purging is done when the count of cached items exceeds the maximum number of items allowed in the cache. The private purge method will remove the oldest P entries from the cache where P is the number of 'purge items' as set with the initialize() method.

Instead of initializing the cache (setting the max and purge item counts) using a constructor, am initialize() method is used. The constructors never throw exceptions. If initialize() fails, it returns false. The get() and put() methods may throw exceptions.

The cache is not thread-safe.

Template Parameters

VALUE

As of 10/17/23 only tested with std::string

Definition at line 64 of file MemoryCache.h.

Member Function Documentation

clear()

template<typename VALUE>

virtual void ngap::MemoryCache< VALUE >::clear ( )

inlinevirtual

Clear the cache.

Definition at line 166 of file MemoryCache.h.

get()

template<typename VALUE>

virtual bool ngap::MemoryCache< VALUE >::get ( const std::string & key, VALUE & value )

inlinevirtual

Get the item from the cache. If the item is not in the cache, the value-result parameter is not modified.

Parameters

key
value	Value-result parameter; operator=() is used to copy the value of the cached item.

Returns

Return True if the item is in the cache, false otherwise.

Definition at line 133 of file MemoryCache.h.

initialize()

template<typename VALUE>

virtual bool ngap::MemoryCache< VALUE >::initialize ( int max_items, int purge_items )

inlinevirtual

Initialize the cache.

Parameters

max_items	Must be greater than zero
purge_items	Must be greater than zero

Returns

Return True if the cache was initialized, false otherwise.

Definition at line 117 of file MemoryCache.h.

put()

template<typename VALUE>

virtual void ngap::MemoryCache< VALUE >::put ( const std::string & key, const VALUE & value )

inlinevirtual

Put the item in the cache. If the key is already in the cache, the value is updated.

Parameters

key
value

Definition at line 149 of file MemoryCache.h.

size()

template<typename VALUE>

virtual unsigned long ngap::MemoryCache< VALUE >::size ( ) const

inlinevirtual

How many items are in the cache.

Definition at line 163 of file MemoryCache.h.

Friends And Related Symbol Documentation

MemoryCacheTest

template<typename VALUE>

friend class MemoryCacheTest

friend

Definition at line 102 of file MemoryCache.h.

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

• MemoryCache.h