CacheObject

java.lang.Object

org.h2.util.CacheObject

All Implemented Interfaces:: Comparable<CacheObject>

Direct Known Subclasses:: CacheHead

public abstract class CacheObject extends Object implements Comparable<CacheObject>

The base object for all cached objects.

Field Summary

Fields

Modifier and Type

Field

Description

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.
Constructor Summary

Constructors

Constructor

Description

CacheObject()
Method Summary

Modifier and Type

Method

Description

abstract boolean

canRemove()

Check if the object can be removed from the cache.

int

compareTo(CacheObject other)

abstract int

getMemory()

Get the estimated used memory.

int

getPos()

boolean

isChanged()

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

boolean

isStream()

void

setChanged(boolean b)

void

setPos(int pos)

Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Details
- 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.
Constructor Details
- CacheObject
  
  public CacheObject()
Method Details
- 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
- getMemory
  
  public abstract int getMemory()
  
  Get the estimated used memory.
  
  Returns:
  
  number of words (one word is 4 bytes)
- 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)
- compareTo
  
  public int compareTo(CacheObject other)
  
  Specified by:
  
  compareTo in interface Comparable<CacheObject>
- isStream
  
  public boolean isStream()