class SimpleCache in Tinman.Core.Caching

A cache that uses a simple LRU (least-recently-used) replacement scheme.

sealed class

SimpleCache

implements

ICacheBase<int64>

Public / Attributes

Capacity

The capacity of this cache.

public property	Capacity { get }
type	int32
value	[>0]	The maximum number of entries this cache can hold.
implements	ICacheBase.Capacity

InvalidId

The page ID value that represents non-existent mappings.

public property	InvalidId { get }
type	int64
value		The invalid page ID value.
implements	ICacheBase.InvalidId

Oldest

Returns the index of the oldest cache page.

public property	Oldest { get }
type	int32
value	[-1..Capacity-1]	Index of the least-recently used cache page or -1 if all pages are unused.
implements	ICacheBase.Oldest

Public / Constructors

SimpleCache

Creates a new instance of SimpleCache.

public constructor	SimpleCache (int32 capacity, int64 invalidId)
params	capacity	[>0]	The cache capacity.
	invalidId		The page ID value that represents an invalid page ID. Unused cached slots will be set to this value.

Public / Methods

EvictAll

Evicts all pages from the cache.

public method	EvictAll ()
implements	ICacheBase.EvictAll

EvictId

Evicts the given page from the cache.

public method	EvictId (int64 pageId)
params	pageId		The cache page ID.
implements	ICacheBase.EvictId

Remarks:

Requesting the given page later will cause a cache miss.

EvictIndex

Evicts the given page from the cache.

public method	EvictIndex (int32 pageIndex)
params	pageIndex	[0..Capacity-1]	The cache page index.
implements	ICacheBase.EvictIndex

Remarks:

Requesting the given page later will cause a cache miss.

Fetch

Fetches a page from the cache, loading it if necessary.

public method	Fetch (int64 pageId)
type	int32
params	pageId		The page ID.
returns			[>=0]: The page is present in the cache, the return value is its index. [<=-1]: The page is not present in the cache and shall be loaded into the cache using the page index given by -1-value, where value is the value that is returned by this method.
implements	ICacheBase.Fetch

GetId

Returns the page ID of the given page.

public method	GetId (int32 pageIndex)
type	int64
params	pageIndex	[0..Capacity-1]	The page index.
returns			The page ID.
implements	ICacheBase.GetId

Remarks:

The state of the cache is not modified by this method.

GetIndex

Returns the cache page index of the given page.

public method	GetIndex (int64 pageId, bool hitPage = false)
type	int32
params	pageId		The page ID.
	hitPage		Update state of the cache by hitting the page if it exists?
returns		[>=-1]	The cache page index or -1.
implements	ICacheBase.GetIndex

Remarks:

The state of the cache is not modified by this method if hitPage is false.

Use

The given cache page has been used.

public method	Use (int32 pageIndex)
params	pageIndex	[0..Capacity-1]	The page index.
implements	ICacheBase.Use

Remarks:

Use this method to avoid specific pages to get evicted from the cache too soon.