CacheTQ

java.lang.Object
- org.h2.util.CacheTQ

All Implemented Interfaces:

Cache
```
public class CacheTQ
extends java.lang.Object
implements Cache
```
An alternative cache implementation. This implementation uses two caches: a LRU cache and a FIFO cache. Entries are first kept in the FIFO cache, and if referenced again then marked in a hash set. If referenced again, they are moved to the LRU cache. Stream pages are never added to the LRU cache. It is supposed to be more or less scan resistant, and it doesn't cache large rows in the LRU cache.

Method Summary

Methods
Modifier and Type	Method and Description
`void`	`clear()` Clear the cache.
`CacheObject`	`find(int pos)` Get an element from the cache if it is available.
`CacheObject`	`get(int pos)` Get an element in the cache if it is available.
`java.util.ArrayList<CacheObject>`	`getAllChanged()` Get all objects in the cache that have been changed.
`int`	`getMaxMemory()` Get the maximum memory to be used.
`int`	`getMemory()` Get the used size in KB.
`void`	`put(CacheObject r)` Add an element to the cache.
`boolean`	`remove(int pos)` Remove an object from the cache.
`void`	`setMaxMemory(int maxMemoryKb)` Set the maximum memory to be used by this cache.
`CacheObject`	`update(int pos, CacheObject record)` Update an element in the cache.

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

- Method Detail
  - clear
```
public void clear()
```
    Description copied from interface: Cache
    
    Clear the cache.
    
    Specified by:
    
    clear in interface Cache
  - find
```
public CacheObject find(int pos)
```
    Description copied from interface: Cache
    
    Get an element from the cache if it is available. This will not move the item to the front of the list.
    
    Specified by:
    
    find in interface Cache
    
    Parameters:
    pos - the unique key of the element
    
    Returns:
    the element or null
  - get
```
public CacheObject get(int pos)
```
    Description copied from interface: Cache
    
    Get an element in the cache if it is available. This will move the item to the front of the list.
    
    Specified by:
    
    get in interface Cache
    
    Parameters:
    pos - the unique key of the element
    
    Returns:
    the element or null
  - getAllChanged
```
public java.util.ArrayList<CacheObject> getAllChanged()
```
    Description copied from interface: Cache
    
    Get all objects in the cache that have been changed.
    
    Specified by:
    
    getAllChanged in interface Cache
    
    Returns:
    the list of objects
  - getMaxMemory
```
public int getMaxMemory()
```
    Description copied from interface: Cache
    
    Get the maximum memory to be used.
    
    Specified by:
    
    getMaxMemory in interface Cache
    
    Returns:
    the maximum size in KB
  - getMemory
```
public int getMemory()
```
    Description copied from interface: Cache
    
    Get the used size in KB.
    
    Specified by:
    
    getMemory in interface Cache
    
    Returns:
    the current size in KB
  - put
```
public void put(CacheObject r)
```
    Description copied from interface: Cache
    
    Add an element to the cache. Other items may fall out of the cache because of this. It is not allowed to add the same record twice.
    
    Specified by:
    
    put in interface Cache
    
    Parameters:
    r - the object
  - remove
```
public boolean remove(int pos)
```
    Description copied from interface: Cache
    
    Remove an object from the cache.
    
    Specified by:
    
    remove in interface Cache
    
    Parameters:
    pos - the unique key of the element
    
    Returns:
    true if the key was in the cache
  - setMaxMemory
```
public void setMaxMemory(int maxMemoryKb)
```
    Description copied from interface: Cache
    
    Set the maximum memory to be used by this cache.
    
    Specified by:
    
    setMaxMemory in interface Cache
    
    Parameters:
    maxMemoryKb - the maximum size in KB
  - update
```
public CacheObject update(int pos,
                 CacheObject record)
```
    Description copied from interface: Cache
    
    Update an element in the cache. This will move the item to the front of the list.
    
    Specified by:
    
    update in interface Cache
    
    Parameters:
    pos - the unique key of the element
    record - the element
    
    Returns:
    the element

Class CacheTQ

Method Summary

Methods inherited from class java.lang.Object

Method Detail

clear

find

get

getAllChanged

getMaxMemory

getMemory

put

remove

setMaxMemory

update