org.h2.util
Class CacheObject

java.lang.Object
  org.h2.util.CacheObject

Direct Known Subclasses:

CacheHead, Record

public abstract class CacheObject
extends java.lang.Object

The base object for all cached objects.

Field Summary

protected int	blockCount The number of blocks occupied by this object.
CacheObject	cacheChained The next element in the hash chain.
CacheObject	cacheNext The next element in the LRU linked list.
CacheObject	cachePrevious The previous element in the LRU linked list.
int	cacheQueue The cache queue identifier.

Constructor Summary

CacheObject()

Method Summary

abstract boolean	canRemove() Check if the object can be removed from the cache.
int	getBlockCount()
int	getMemorySize() Get the estimated memory size.
int	getPos()
boolean	isChanged() Check if this cache object has been changed and thus needs to be written back to the storage.
boolean	isPinned() Check if this cache object can be removed from the cache.
void	setBlockCount(int size)
void	setChanged(boolean b)
void	setPos(int pos)
static void	sort(ObjectArray<CacheObject> recordList) Order the given list of cache objects by position.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

cachePrevious

public CacheObject cachePrevious

The previous element in the LRU linked list. If the previous element is the head, then this element is the most recently used object.

cacheNext

public CacheObject cacheNext

The next element in the LRU linked list. If the next element is the head, then this element is the least recently used object.

cacheChained

public CacheObject cacheChained

The next element in the hash chain.

cacheQueue

public int cacheQueue

The cache queue identifier. This field is only used for the 2Q cache algorithm.

blockCount

protected int blockCount

The number of blocks occupied by this object.

Constructor Detail

CacheObject

public CacheObject()

Method Detail

canRemove

public abstract boolean canRemove()

Check if the object can be removed from the cache. For example pinned objects can not be removed.

Returns:

true if it can be removed

sort

public static void sort(ObjectArray<CacheObject> recordList)

Order the given list of cache objects by position.

Parameters:

recordList - the list of cache objects

setBlockCount

public void setBlockCount(int size)

getBlockCount

public int getBlockCount()

setPos

public void setPos(int pos)

getPos

public int getPos()

isChanged

public boolean isChanged()

Check if this cache object has been changed and thus needs to be written back to the storage.

Returns:

if it has been changed

setChanged

public void setChanged(boolean b)

isPinned

public boolean isPinned()

Check if this cache object can be removed from the cache.

Returns:

if it can be removed

getMemorySize

public int getMemorySize()

Get the estimated memory size.

Returns:

number of double words (4 bytes)