Package org.zkoss.util

Class FastReadCache<K,​V>

  • All Implemented Interfaces:
    java.io.Serializable, java.lang.Cloneable, Cache<K,​V>
    public class FastReadCache<K,​V>
extends java.lang.Object
implements Cache<K,​V>, java.io.Serializable, java.lang.Cloneable
    A CacheMap that the possibility to have cache hit is much more than not. It maintains a readonly cache (so no need to synchronize), and then clone and replace it if there is a miss. Thus, as time goes, most access can go directly to the readonly cache without any synchronization or cloning.

    Thread safe.

    Since:
    6.0.0
    Author:
    tomyeh
    See Also:
    Serialized Form

    • Constructor Summary

      Constructors 
      Constructor Description
      FastReadCache()
      Constructor.
      FastReadCache​(int maxSize, int lifetime)
      Constructor.
      FastReadCache​(int maxSize, int lifetime, short maxMissCount)
      Constructor.

    • Method Summary

      All Methods Instance Methods Concrete Methods 
      Modifier and Type Method Description
      void clear()
      Clears all objects being cached.
      boolean containsKey​(java.lang.Object key)
      Returns whether the specified key is stored.
      V get​(java.lang.Object key)
      Returns the object of the specified key, or null if not found.
      int getLifetime()
      Returns the minimal lifetime, unit=milliseconds.
      int getMaxSize()
      Returns the maximal allowed size.
      V put​(K key, V value)
      Stores an object to the cache.
      V remove​(java.lang.Object key)
      Removes an object from the cache.
      void setLifetime​(int lifetime)
      Sets the minimal lifetime.
      void setMaxSize​(int maxsize)
      Sets the maximal allowed size.

      • Methods inherited from class java.lang.Object

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

    • Constructor Detail

      • FastReadCache

        public FastReadCache()
        Constructor.

      • FastReadCache

        public FastReadCache​(int maxSize,
                     int lifetime)
        Constructor.

      • FastReadCache

        public FastReadCache​(int maxSize,
                     int lifetime,
                     short maxMissCount)
        Constructor.
        Parameters:
        maxMissCount - a short value from 0 to this for sync the read cache, default is 100.
        Since:
        6.5.2

    • Method Detail

      • containsKey

        public boolean containsKey​(java.lang.Object key)
        Description copied from interface: Cache
        Returns whether the specified key is stored.
        Specified by:
        containsKey in interface Cache<K,​V>

      • get

        public V get​(java.lang.Object key)
        Description copied from interface: Cache
        Returns the object of the specified key, or null if not found.
        Specified by:
        get in interface Cache<K,​V>

      • put

        public V put​(K key,
             V value)
        Description copied from interface: Cache
        Stores an object to the cache.
        Specified by:
        put in interface Cache<K,​V>
        Returns:
        the previous value of the same, or null if no such value

      • remove

        public V remove​(java.lang.Object key)
        Description copied from interface: Cache
        Removes an object from the cache.
        Specified by:
        remove in interface Cache<K,​V>
        Returns:
        the object if found.

      • clear

        public void clear()
        Description copied from interface: Cache
        Clears all objects being cached.
        Specified by:
        clear in interface Cache<K,​V>

      • getLifetime

        public int getLifetime()
        Description copied from interface: Cache
        Returns the minimal lifetime, unit=milliseconds. An mapping won't be removed by GC unless the minimal lifetime or the maximal allowed size exceeds.
        Specified by:
        getLifetime in interface Cache<K,​V>
        See Also:
        Cache.getMaxSize()

      • setLifetime

        public void setLifetime​(int lifetime)
        Description copied from interface: Cache
        Sets the minimal lifetime. Default: Cache.DEFAULT_LIFETIME.
        Specified by:
        setLifetime in interface Cache<K,​V>
        Parameters:
        lifetime - the lifetime, unit=milliseconds; if non-positive, they will be removed immediately.
        See Also:
        Cache.getLifetime()

      • getMaxSize

        public int getMaxSize()
        Description copied from interface: Cache
        Returns the maximal allowed size. Default: Cache.DEFAULT_MAX_SIZE. An mapping won't be removed by GC unless the minimal lifetime or the maximal allowed size exceeds.
        Specified by:
        getMaxSize in interface Cache<K,​V>
        See Also:
        Cache.getLifetime()

      • setMaxSize

        public void setMaxSize​(int maxsize)
        Description copied from interface: Cache
        Sets the maximal allowed size.
        Specified by:
        setMaxSize in interface Cache<K,​V>
        See Also:
        Cache.getMaxSize()