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ACE_LRU_Caching_Strategy Class Template Reference

Defines a Least Recently Used strategy which will decide on the item to be removed from the cache. More...

#include <Caching_Strategies_T.h>

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Public Types

typedef ATTRIBUTES CACHING_ATTRIBUTES

Public Methods

 ACE_LRU_Caching_Strategy (void)
ATTRIBUTES attributes (void)
 Accessor method for the timer attributes. More...

double purge_percent (void)
 Get the percentage of entries to purge. More...

void purge_percent (double percentage)
 Set the percentage of entries to purge. More...

int notify_bind (int result, const ATTRIBUTES &attr)
 This method acts as a notification about the CONTAINERs bind method call. More...

int notify_find (int result, ATTRIBUTES &attr)
 This method acts as a notification about the CONTAINERs find method call. More...

int notify_unbind (int result, const ATTRIBUTES &attr)
 This method acts as a notification about the CONTAINERs unbind method call. More...

int notify_trybind (int result, ATTRIBUTES &attr)
 This method acts as a notification about the CONTAINERs trybind method call. More...

int notify_rebind (int result, const ATTRIBUTES &attr)
 This method acts as a notification about the CONTAINERs rebind method call. More...

CACHING_UTILITY & caching_utility (void)
 Purge the cache. More...

void dump (void) const
 Dumps the state of the object. More...


Private Attributes

ATTRIBUTES timer_
 This element is the one which is the deciding factor for purging of an ITEM. More...

double purge_percent_
 The level about which the purging will happen automagically. More...

CACHING_UTILITY caching_utility_
 This is the helper class which will decide and expunge entries from the cache. More...


Detailed Description

template<class ATTRIBUTES, class CACHING_UTILITY>
class ACE_LRU_Caching_Strategy< ATTRIBUTES, CACHING_UTILITY >

Defines a Least Recently Used strategy which will decide on the item to be removed from the cache.

This is a strategy which makes use of a virtual timer which is updated whenever an item is inserted or looked up in the container. When the need of purging entries arises, the items with the lowest timer values are removed. Explanation of the template parameter list: CONTAINER is any map with entries of type <KEY, VALUE>. The ATTRIBUTES are the deciding factor for purging of entries and should logically be included with the VALUE. Some ways of doing this are: As being a member of the VALUE or VALUE being ACE_Pair<x, ATTRIBUTES>. The CACHING_UTILITY is the class which can be plugged in and which decides the entries to purge.

Definition at line 197 of file Caching_Strategies_T.h.


Member Typedef Documentation

template<class ATTRIBUTES, class CACHING_UTILITY>
typedef ATTRIBUTES ACE_LRU_Caching_Strategy::CACHING_ATTRIBUTES
 

Definition at line 202 of file Caching_Strategies_T.h.


Constructor & Destructor Documentation

template<class ATTRIBUTES, class CACHING_UTILITY>
ACE_LRU_Caching_Strategy< ATTRIBUTES, CACHING_UTILITY >::ACE_LRU_Caching_Strategy void   
 

The <container> is the map in which the entries reside. The timer attribute is initialed to zero in this constructor. And the <purge_percent> field denotes the percentage of the entries in the cache which can be purged automagically and by default is set to 10%.

Definition at line 27 of file Caching_Strategies_T.cpp.

00028   : timer_ (0),
00029     purge_percent_ (10)
00030 {
00031 }


Member Function Documentation

template<class ATTRIBUTES, class CACHING_UTILITY>
ACE_INLINE ATTRIBUTES ACE_LRU_Caching_Strategy< ATTRIBUTES, CACHING_UTILITY >::attributes void   
 

Accessor method for the timer attributes.

Definition at line 113 of file Caching_Strategies_T.i.

References timer_.

00114 {
00115   return this->timer_;
00116 }

template<class ATTRIBUTES, class CACHING_UTILITY>
ACE_INLINE CACHING_UTILITY & ACE_LRU_Caching_Strategy< ATTRIBUTES, CACHING_UTILITY >::caching_utility void   
 

Purge the cache.

Definition at line 185 of file Caching_Strategies_T.i.

References caching_utility_.

00186 {
00187   return this->caching_utility_;
00188 }

template<class ATTRIBUTES, class CACHING_UTILITY>
ACE_INLINE void ACE_LRU_Caching_Strategy< ATTRIBUTES, CACHING_UTILITY >::dump void    const
 

Dumps the state of the object.

Definition at line 191 of file Caching_Strategies_T.i.

References ACE_BEGIN_DUMP, ACE_DEBUG, ACE_END_DUMP, ACE_LIB_TEXT, ACE_TRACE, and LM_DEBUG.

00192 {
00193   ACE_TRACE ("ACE_LRU_Caching_Strategy::dump");
00194 
00195   ACE_DEBUG ((LM_DEBUG, ACE_BEGIN_DUMP, this));
00196   ACE_DEBUG ((LM_DEBUG,  ACE_LIB_TEXT ("timer_ = %d "), this->timer_));
00197   ACE_DEBUG ((LM_DEBUG, ACE_END_DUMP));
00198 }

template<class ATTRIBUTES, class CACHING_UTILITY>
ACE_INLINE int ACE_LRU_Caching_Strategy< ATTRIBUTES, CACHING_UTILITY >::notify_bind int    result,
const ATTRIBUTES &    attr
 

This method acts as a notification about the CONTAINERs bind method call.

Definition at line 131 of file Caching_Strategies_T.i.

References timer_.

00133 {
00134   ACE_UNUSED_ARG (attr);
00135 
00136   if (result == 0)
00137     ++this->timer_;
00138 
00139   return result;
00140 }

template<class ATTRIBUTES, class CACHING_UTILITY>
ACE_INLINE int ACE_LRU_Caching_Strategy< ATTRIBUTES, CACHING_UTILITY >::notify_find int    result,
ATTRIBUTES &    attr
 

This method acts as a notification about the CONTAINERs find method call.

Definition at line 143 of file Caching_Strategies_T.i.

References timer_.

00145 {
00146   if (result == 0)
00147     {
00148       attr = this->timer_;
00149       ++this->timer_;
00150     }
00151 
00152   return result;
00153 }

template<class ATTRIBUTES, class CACHING_UTILITY>
ACE_INLINE int ACE_LRU_Caching_Strategy< ATTRIBUTES, CACHING_UTILITY >::notify_rebind int    result,
const ATTRIBUTES &    attr
 

This method acts as a notification about the CONTAINERs rebind method call.

Definition at line 173 of file Caching_Strategies_T.i.

References timer_.

00175 {
00176   ACE_UNUSED_ARG (attr);
00177 
00178   if (result == 0)
00179     ++this->timer_;
00180 
00181   return result;
00182 }

template<class ATTRIBUTES, class CACHING_UTILITY>
ACE_INLINE int ACE_LRU_Caching_Strategy< ATTRIBUTES, CACHING_UTILITY >::notify_trybind int    result,
ATTRIBUTES &    attr
 

This method acts as a notification about the CONTAINERs trybind method call.

Definition at line 164 of file Caching_Strategies_T.i.

00166 {
00167   ACE_UNUSED_ARG (attr);
00168 
00169   return result;
00170 }

template<class ATTRIBUTES, class CACHING_UTILITY>
ACE_INLINE int ACE_LRU_Caching_Strategy< ATTRIBUTES, CACHING_UTILITY >::notify_unbind int    result,
const ATTRIBUTES &    attr
 

This method acts as a notification about the CONTAINERs unbind method call.

Definition at line 156 of file Caching_Strategies_T.i.

00158 {
00159   ACE_UNUSED_ARG (attr);
00160   return result;
00161 }

template<class ATTRIBUTES, class CACHING_UTILITY>
ACE_INLINE void ACE_LRU_Caching_Strategy< ATTRIBUTES, CACHING_UTILITY >::purge_percent double    percentage
 

Set the percentage of entries to purge.

Definition at line 125 of file Caching_Strategies_T.i.

References purge_percent_.

00126 {
00127   this->purge_percent_ = percentage;
00128 }

template<class ATTRIBUTES, class CACHING_UTILITY>
ACE_INLINE double ACE_LRU_Caching_Strategy< ATTRIBUTES, CACHING_UTILITY >::purge_percent void   
 

Get the percentage of entries to purge.

Definition at line 119 of file Caching_Strategies_T.i.

References purge_percent_.

00120 {
00121   return this->purge_percent_;
00122 }


Member Data Documentation

template<class ATTRIBUTES, class CACHING_UTILITY>
CACHING_UTILITY ACE_LRU_Caching_Strategy::caching_utility_ [private]
 

This is the helper class which will decide and expunge entries from the cache.

Definition at line 271 of file Caching_Strategies_T.h.

Referenced by caching_utility.

template<class ATTRIBUTES, class CACHING_UTILITY>
double ACE_LRU_Caching_Strategy::purge_percent_ [private]
 

The level about which the purging will happen automagically.

Definition at line 267 of file Caching_Strategies_T.h.

Referenced by purge_percent.

template<class ATTRIBUTES, class CACHING_UTILITY>
ATTRIBUTES ACE_LRU_Caching_Strategy::timer_ [private]
 

This element is the one which is the deciding factor for purging of an ITEM.

Definition at line 264 of file Caching_Strategies_T.h.

Referenced by attributes, notify_bind, notify_find, and notify_rebind.


The documentation for this class was generated from the following files:
Generated on Mon Jun 16 12:49:37 2003 for ACE by doxygen1.2.14 written by Dimitri van Heesch, © 1997-2002