Package org.h2.util

Class CacheLRU

  • All Implemented Interfaces:
    Cache
    public class CacheLRU
extends java.lang.Object
implements Cache
    A cache implementation based on the last recently used (LRU) algorithm.

    • Method Summary

      All Methods Static Methods Instance Methods Concrete Methods 
      Modifier and Type Method 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.
      static Cache getCache​(CacheWriter writer, java.lang.String cacheType, int cacheSize)
      Create a cache of the given type and size.
      int getMaxMemory()
      Get the maximum memory to be used.
      int getMemory()
      Get the used size in KB.
      void put​(CacheObject rec)
      Add an element to the cache.
      boolean remove​(int pos)
      Remove an object from the cache.
      void setMaxMemory​(int maxKb)
      Set the maximum memory to be used by this cache.
      CacheObject update​(int pos, CacheObject rec)
      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

      • getCache

        public static Cache getCache​(CacheWriter writer,
                             java.lang.String cacheType,
                             int cacheSize)
        Create a cache of the given type and size.
        Parameters:
        writer - the cache writer
        cacheType - the cache type
        cacheSize - the size
        Returns:
        the cache object

      • clear

        public void clear()
        Description copied from interface: Cache
        Clear the cache.
        Specified by:
        clear in interface Cache

      • put

        public void put​(CacheObject rec)
        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:
        rec - the object

      • update

        public CacheObject update​(int pos,
                          CacheObject rec)
        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
        rec - the element
        Returns:
        the element

      • 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

      • 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

      • setMaxMemory

        public void setMaxMemory​(int maxKb)
        Description copied from interface: Cache
        Set the maximum memory to be used by this cache.
        Specified by:
        setMaxMemory in interface Cache
        Parameters:
        maxKb - the maximum size in KB

      • 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