Package org.greenrobot.essentials

Class ObjectCache<KEY,VALUE>

java.lang.Object
org.greenrobot.essentials.ObjectCache<KEY,VALUE>
public class ObjectCache<KEY,VALUE> extends Object
An in-memory object cache supporting soft/weak/strong references, maximum size (clearing the entries that were put first), and time-based expiration.

  • Field Details

    • values

      private final Map<KEY,ObjectCache.CacheEntry<VALUE>> values

    • referenceType

      private final ObjectCache.ReferenceType referenceType

    • isStrongReference

      private final boolean isStrongReference

    • maxSize

      private final int maxSize

    • expirationMillis

      private final long expirationMillis

    • isExpiring

      private final boolean isExpiring

    • nextCleanUpTimestamp

      private volatile long nextCleanUpTimestamp

    • countPutCountSinceEviction

      private volatile int countPutCountSinceEviction

    • countPut

      private volatile int countPut

    • countHit

      private volatile int countHit

    • countMiss

      private volatile int countMiss

    • countExpired

      private volatile int countExpired

    • countRefCleared

      private volatile int countRefCleared

    • countEvicted

      private volatile int countEvicted

  • Constructor Details

    • ObjectCache

      public ObjectCache(ObjectCache.ReferenceType referenceType, int maxSize, long expirationMillis)
      Create a cache according to the given configuration.
      Parameters:
      referenceType - SOFT is usually a good choice allowing the VM to clear caches when running low on memory. STRONG may also be preferred, e.g. when the required space is granted.
      maxSize - The maximum number of entries stored by this cache
      expirationMillis -

  • Method Details

    • put

      public VALUE put(KEY key, VALUE object)
      Stores an new entry in the cache.

    • getValueForRemoved

      private VALUE getValueForRemoved(ObjectCache.CacheEntry<VALUE> entry)

    • getValue

      private VALUE getValue(KEY keyForRemoval, ObjectCache.CacheEntry<VALUE> entry)

    • putAll

      public void putAll(Map<KEY,VALUE> mapDataToPut)
      Stores all entries contained in the given map in the cache.

    • get

      public VALUE get(KEY key)
      Get the cached entry or null if no valid cached entry is found.

    • clear

      public void clear()
      Clears all cached entries.

    • remove

      public VALUE remove(KEY key)
      Removes an entry from the cache.
      Returns:
      The removed entry

    • evictToTargetSize

      public void evictToTargetSize(int targetSize)

    • checkCleanUpObsoleteEntries

      void checkCleanUpObsoleteEntries()

    • cleanUpObsoleteEntries

      public int cleanUpObsoleteEntries()
      Iterates over all entries to check for obsolete ones (time expired or reference cleared).

      Note: Usually you don't need to call this method explicitly, because it is called internally in certain conditions when space has to be reclaimed.

    • containsKey

      public boolean containsKey(KEY key)

    • containsKeyWithValue

      public boolean containsKeyWithValue(KEY key)

    • keySet

      public Set<KEY> keySet()

    • getMaxSize

      public int getMaxSize()

    • size

      public int size()

    • getCountPut

      public int getCountPut()

    • getCountHit

      public int getCountHit()

    • getCountMiss

      public int getCountMiss()

    • getCountExpired

      public int getCountExpired()

    • getCountRefCleared

      public int getCountRefCleared()

    • getCountEvicted

      public int getCountEvicted()

    • toString

      public String toString()
      Overrides:
      toString in class Object

    • getStatsStringRemoved

      public String getStatsStringRemoved()
      Often used in addition to toString() to print out states: details why entries were removed.