Package com.tangosol.net.cache

Class LocalCache

java.lang.Object
java.util.AbstractMap
com.tangosol.util.SafeHashMap
com.tangosol.net.cache.OldCache
com.tangosol.net.cache.LocalCache
All Implemented Interfaces:
CacheMap, ConfigurableCacheMap, ObservableMap, Serializable, Cloneable, Map
public class LocalCache extends OldCache implements CacheMap
A LocalCache implementation that supports the JCache API, CacheLoader and CacheStore objects.
Since:
Coherence 2.2
Author:
cp 2003.05.30
See Also:

  • Field Details

    • DEFAULT_UNITS

      public static final int DEFAULT_UNITS
      By default, the cache size (in units) is infinite.
      See Also:

    • DEFAULT_EXPIRE

      public static final int DEFAULT_EXPIRE
      By default, the cache entries never expire.
      See Also:

    • DEFAULT_KEY_MASK

      protected final LocalCache.KeyMask DEFAULT_KEY_MASK
      The default key mask that ignores nothing.

  • Constructor Details

    • LocalCache

      public LocalCache()
      Construct the cache manager.

    • LocalCache

      public LocalCache(int cUnits)
      Construct the cache manager.
      Parameters:
      cUnits - the number of units that the cache manager will cache before pruning the cache

    • LocalCache

      public LocalCache(int cUnits, int cExpiryMillis)
      Construct the cache manager.
      Parameters:
      cUnits - the number of units that the cache manager will cache before pruning the cache
      cExpiryMillis - the number of milliseconds that each cache entry lives before being automatically expired

    • LocalCache

      public LocalCache(int cUnits, int cExpiryMillis, CacheLoader loader)
      Construct the cache manager.
      Parameters:
      cUnits - the number of units that the cache manager will cache before pruning the cache
      cExpiryMillis - the number of milliseconds that each cache entry lives before being automatically expired
      loader - the CacheLoader or CacheStore to use

  • Method Details

    • clear

      public void clear()
      Removes all mappings from this map.
      Specified by:
      clear in interface Map
      Overrides:
      clear in class OldCache

    • remove

      public Object remove(Object oKey)
      Removes the mapping for this key from this map if present.
      Specified by:
      remove in interface Map
      Overrides:
      remove in class OldCache
      Parameters:
      oKey - key whose mapping is to be removed from the map
      Returns:
      previous value associated with specified key, or null if there was no mapping for key. A null return can also indicate that the map previously associated null with the specified key, if the implementation supports null values

    • getCacheLoader

      public CacheLoader getCacheLoader()
      Determine the loader used by this LocalCache, if any.
      Returns:
      the loader used by this LocalCache, or null if none

    • setCacheLoader

      public void setCacheLoader(CacheLoader loader)
      Specify the loader used by this LocalCache.
      Parameters:
      loader - loader to use, or null

    • get

      public Object get(Object oKey)
      If the specified item is in the cache, return it. Otherwise, load the value for the specified key and return it.
      Specified by:
      get in interface Map
      Overrides:
      get in class OldCache
      Parameters:
      oKey - the key to the desired cached item
      Returns:
      the value corresponding to the specified key, otherwise null

    • getEntry

      public SafeHashMap.Entry getEntry(Object oKey)
      Locate an Entry in the hash map based on its key. If the Entry is not in the cache, load the Entry for the specified key and return it.
      Overrides:
      getEntry in class OldCache
      Parameters:
      oKey - the key to the desired cached Entry
      Returns:
      the Entry corresponding to the specified key, otherwise null

    • getAll

      public Map getAll(Collection colKeys)
      Get all the specified keys, if they are in the cache. For each key that is in the cache, that key and its corresponding value will be placed in the map that is returned by this method. The absence of a key in the returned map indicates that it was not in the cache, which may imply (for caches that can load behind the scenes) that the requested data could not be loaded.

      The result of this method is defined to be semantically the same as the following implementation, without regards to threading issues: 

      
 Map map = new AnyMap(); // could be hash map or ...
 for (Iterator iter = col.iterator(); iter.hasNext(); )
     {
     Object oKey = iter.next();
     Object oVal = get(oKey);
     if (oVal != null || containsKey(oKey))
         {
         map.put(oKey, oVal);
         }
     }
 return map;

      Specified by:
      getAll in interface CacheMap
      Overrides:
      getAll in class OldCache
      Parameters:
      colKeys - a collection of keys that may be in the named cache
      Returns:
      a Map of keys to values for the specified keys passed in col

    • load

      public void load(Object oKey)
      Indicates to the cache that the specified key should be loaded into the cache, if it is not already in the cache. This provides a means to "pre-load" a single entry into the cache using the cache's loader.

      If a valid entry with the specified key already exists in the cache, or if the cache does not have a loader, then this method has no effect.

      An implementation may perform the load operation asynchronously.

      Parameters:
      oKey - the key to request to be loaded

    • loadAll

      public void loadAll()
      Indicates to the cache that it should load data from its loader to fill the cache; this is sometimes referred to as "pre-loading" or "warming" a cache.

      The specific set of data that will be loaded is unspecified. The implementation may choose to load all data, some specific subset of the data, or no data. An implementation may require that the loader implement the IterableCacheLoader interface in order for this method to load any data.

      An implementation may perform the load operation asynchronously.

    • loadAll

      public void loadAll(Collection colKeys)
      Indicates to the cache that the specified keys should be loaded into the cache, if they are not already in the cache. This provides a means to "pre-load" entries into the cache using the cache's loader.

      The result of this method is defined to be semantically the same as the following implementation: 

      
 CacheLoader loader = getCacheLoader();
 if (loader != null && !colKeys.isEmpty())
     {
     Set setRequest = new HashSet(colKeys);
     setRequest.removeAll(peekAll(colKeys).keySet());
     if (!setRequest.isEmpty())
         {
         Map map = loader.loadAll(colKeys);
         if (!map.isEmpty())
             {
             putAll(map);
             }
         }
     }

      Parameters:
      colKeys - a collection of keys to request to be loaded

    • peek

      public Object peek(Object oKey)
      Checks for a valid entry corresponding to the specified key in the cache, and returns the corresponding value if it is. If it is not in the cache, returns null, and does not attempt to load the value using its cache loader.
      Parameters:
      oKey - the key to "peek" into the cache for
      Returns:
      the value corresponding to the specified key

    • peekAll

      public Map peekAll(Collection colKeys)
      Checks for a valid entry corresponding to each specified key in the cache, and places the corresponding value in the returned map if it is. For each key that is not in the cache, no entry is placed into the returned map. The cache does not attempt to load any values using its cache loader.

      The result of this method is defined to be semantically the same as the following implementation, without regards to threading issues: 

      
 Map map = new HashMap();
 for (Iterator iter = colKeys.iterator(); iter.hasNext(); )
     {
     Object oKey   = iter.next();
     Object oValue = peek(oKey);
     if (oValue != null || containsKey(oKey))
         {
         map.put(oKey, oValue);
         }
     }
 return map;

      Parameters:
      colKeys - a collection of keys to "peek" into the cache for
      Returns:
      a Map of keys that were found in the cache and their values

    • getCacheStore

      protected CacheStore getCacheStore()
      Determine the store used by this LocalCache, if any.
      Returns:
      the CacheStore used by this LocalCache, or null if none

    • getKeyMask

      protected LocalCache.KeyMask getKeyMask()
      ThreadLocal: Get the current key mask for the current thread.
      Returns:
      the current key mask

    • setKeyMask

      protected void setKeyMask(LocalCache.KeyMask mask)
      ThreadLocal: Set the key mask for the current thread.
      Parameters:
      mask - the new key mask, or null to clear the mask

    • removeEvicted

      protected boolean removeEvicted(OldCache.Entry entry)
      Remove an entry (if it is eligible for eviction) because it has expired.
      Overrides:
      removeEvicted in class OldCache
      Parameters:
      entry - the expired cache entry
      Returns:
      true iff the entry was removed

    • instantiateMapEvent

      protected MapEvent instantiateMapEvent(int nId, Object oKey, Object oValueOld, Object oValueNew)
      Factory pattern: instantiate a new CacheEvent corresponding to the specified parameters.
      Overrides:
      instantiateMapEvent in class OldCache
      Parameters:
      nId - the event Id
      oKey - the key
      oValueOld - the old value
      oValueNew - the new value
      Returns:
      a new instance of the CacheEvent class (or a subclass thereof)

    • instantiateInternalListener

      protected MapListener instantiateInternalListener()
      Factory pattern: Instantiate an internal MapListener to listen to this cache and report changes to the CacheStore.
      Returns:
      a new MapListener instance

    • instantiateEntry

      protected SafeHashMap.Entry instantiateEntry()
      Factory method. This method exists to allow the OldCache class to be easily inherited from by allowing the Entry class to be easily sub-classed.
      Overrides:
      instantiateEntry in class OldCache
      Returns:
      an instance of Entry that holds the passed cache value