Class LocalCache.Entry

A holder for a cached value.

Inheritance

object

LocalCache.Entry

Implements

IInvocableCacheEntry

IConfigurableCacheEntry

ICacheEntry

Inherited Members

object.Equals(object)

object.Equals(object, object)

object.GetHashCode()

object.GetType()

object.MemberwiseClone()

object.ReferenceEquals(object, object)

Namespace: Tangosol.Net.Cache

Assembly: Coherence.dll

Syntax

public class LocalCache.Entry : IInvocableCacheEntry, IConfigurableCacheEntry, ICacheEntry

Constructors

Entry(LocalCache, object, object)

Construct the cacheable entry that holds the cached value.

Declaration

public Entry(LocalCache localCache, object key, object value)

Parameters

Type	Name	Description
LocalCache	localCache	The local cache for this entry.
object	key	The key of this entry.
object	value	The value of this entry.

Fields

m_cache

Parent cache.

Declaration

protected LocalCache m_cache

Field Value

Type	Description
LocalCache

m_key

Entry's key.

Declaration

protected object m_key

Field Value

Type	Description
object

m_value

Entry's value.

Declaration

protected object m_value

Field Value

Type	Description
object

Properties

Cache

Parent cache.

Declaration

public virtual LocalCache Cache { get; set; }

Property Value

Type	Description
LocalCache	Parent cache.

CreatedMillis

Determine when the cache entry was created.

Declaration

public virtual long CreatedMillis { get; }

Property Value

Type	Description
long	The date/time value, in millis, when the entry was created.

ExpiryMillis

Determine when the cache entry will expire, if ever.

Declaration

public virtual long ExpiryMillis { get; set; }

Property Value

Type	Description
long	The date/time value, in millis, when the entry will (or did) expire; zero indicates no expiry.

Remarks

Note that if the cache is configured for automatic expiry, each subsequent update to this cache entry will reschedule the expiry time.

IsDiscarded

Determine if this entry has already been discarded from the cache.

Declaration

protected virtual bool IsDiscarded { get; }

Property Value

Type	Description
bool	true if this entry has been discarded.

IsExpired

Determine if the cache entry has expired.

Declaration

public virtual bool IsExpired { get; }

Property Value

Type	Description
bool	true if the cache entry was subject to automatic expiry and the current time is greater than the entry's expiry time.

IsPresent

Determine if this entry exists in the cache.

Declaration

public virtual bool IsPresent { get; }

Property Value

Type	Description
bool	true if this entry exists in the containing cache.

Remarks

If the entry is not present, it can be created by setting the Value property. If the entry is present, it can be destroyed by calling Remove(bool).

Key

Gets the key corresponding to this entry.

Declaration

public virtual object Key { get; }

Property Value

Type	Description
object	The key corresponding to this entry; may be null if the underlying dictionary supports null keys.

LastTouchMillis

Determine when the cache entry was last touched.

Declaration

public virtual long LastTouchMillis { get; }

Property Value

Type	Description
long	The date/time value, in millis, when the entry was most recently touched.

Priority

Calculate a cache priority.

Declaration

public virtual int Priority { get; }

Property Value

Type	Description
int	A value between 0 and 10, 0 being the highest priority.

TouchCount

Determine the number of times that the cache entry has been touched.

Declaration

public virtual int TouchCount { get; }

Property Value

Type	Description
int	The number of times that the cache entry has been touched.

Units

Determine the number of cache units used by this Entry.

Declaration

public virtual int Units { get; set; }

Property Value

Type	Description
int	An integer value 0 or greater, with a larger value signifying a higher cost; -1 implies that the Entry has been discarded.

Value

Gets or sets the value corresponding to this entry.

Declaration

public virtual object Value { get; set; }

Property Value

Type	Description
object	The value corresponding to this entry; may be null if the value is null or if the entry does not exist in the cache.

Methods

CalculateUnits(object)

Calculate a cache cost for the specified object.

Declaration

public virtual int CalculateUnits(object value)

Parameters

Type	Name	Description
object	value	The cache value to evaluate for unit cost.

Returns

Type	Description
int	An integer value 0 or greater, with a larger value signifying a higher cost.

Remarks

The default implementation uses the unit calculator type of the containing cache.

Discard()

Called to inform the Entry that it is no longer used.

Declaration

protected virtual void Discard()

Remarks

This method should only be called while holding the LocalCache write lock.

Extract(IValueExtractor)

Extract a value out of the entry's value.

Declaration

public virtual object Extract(IValueExtractor extractor)

Parameters

Type	Name	Description
IValueExtractor	extractor	An IValueExtractor to apply to the entry's value

Returns

Type	Description
object	The extracted value.

Remarks

Calling this method is semantically equivalent to extractor.Extract(entry.Value), but this method may be significantly less expensive because the resultant value may be obtained from a forward index, for example.

IndexOfMSB(int)

Determine the most significant bit of the passed integral value.

Declaration

public virtual int IndexOfMSB(int n)

Parameters

Type	Name	Description
int	n	An int.

Returns

Type	Description
int	-1 if no bits are set; otherwise, the bit position p of the most significant bit such that 1 << p is the most significant bit of n

Remove(bool)

Remove this entry from the cache if it is present in the cache.

Declaration

public virtual void Remove(bool isSynthetic)

Parameters

Type	Name	Description
bool	isSynthetic	Pass true only if the removal from the dictionary should be treated as a synthetic event.

Remarks

This method supports both the operation corresponding to IDictionary.Remove as well as synthetic operations such as eviction. If the containing cache does not differentiate between the two, then this method will always be identical to IInvocableCache.Remove(Key).

ResetTouchCount()

Reset the number of times that the cache entry has been touched.

Declaration

public void ResetTouchCount()

Remarks

The touch count does not get reset to zero, but rather to a fraction of its former self; this prevents long lived items from gaining an unasailable advantage in the eviction process.

ScheduleExpiry()

Reschedule the cache entry expiration.

Declaration

protected virtual void ScheduleExpiry()

SetValue(object, bool)

Store the value corresponding to this entry.

Declaration

public virtual void SetValue(object value, bool isSynthetic)

Parameters

Type	Name	Description
object	value	The new value for this entry.
bool	isSynthetic	Pass true only if the insertion into or modification of the cache should be treated as a synthetic event.

Remarks

If the entry does not exist, then the entry will be created by invoking this method, even with a null value (assuming the cache supports null values).

Unlike the property Value, this method does not return the previous value, and as a result may be significantly less expensive (in terms of cost of execution) for certain cache implementations.

ToString()

Render the cache entry as a string.

Declaration

public override string ToString()

Returns

Type	Description
string	The details about this Entry.

Overrides

object.ToString()

Touch()

Called each time the entry is accessed or modified.

Declaration

public virtual void Touch()

Update(IValueUpdater, object)

Update the entry's value.

Declaration

public virtual void Update(IValueUpdater updater, object value)

Parameters

Type	Name	Description
IValueUpdater	updater	An IValueUpdater used to modify the entry's value.
object	value	Value to update target object to.

Remarks

Calling this method is semantically equivalent to:

object target = entry.Value;
updater.Update(target, value);
entry.Value = target;

The benefit of using this method is that it may allow the entry implementation to significantly optimize the operation, such as for purposes of delta updates and backup maintenance.

Operators

implicit operator DictionaryEntry(Entry)

Converts Entry to DictionaryEntry.

Declaration

public static implicit operator DictionaryEntry(LocalCache.Entry entry)

Parameters

Type	Name	Description
LocalCache.Entry	entry	Entry instance.

Returns

Type	Description
DictionaryEntry	DictionaryEntry with key and value extracted from the specified Entry.

implicit operator CacheEntry(Entry)

Converts Entry to CacheEntry.

Declaration

public static implicit operator CacheEntry(LocalCache.Entry entry)

Parameters

Type	Name	Description
LocalCache.Entry	entry	Entry instance.

Returns

Type	Description
CacheEntry	CacheEntry with key and value extracted from the specified Entry.

Implements

IInvocableCacheEntry

IConfigurableCacheEntry

ICacheEntry