Package org.alfresco.repo.cache.lookup

Class EntityLookupCache<K extends java.io.Serializable,​V,​VK extends java.io.Serializable>

  • public class EntityLookupCache<K extends java.io.Serializable,​V,​VK extends java.io.Serializable>
extends java.lang.Object
    A cache for two-way lookups of database entities. These are characterized by having a unique key (perhaps a database ID) and a separate unique key that identifies the object. If no cache is given, then all calls are passed through to the backing DAO.

    The keys must have good equals and hashCode implementations and must respect the case-sensitivity of the use-case.

    All keys will be unique to the given cache region, allowing the cache to be shared between instances of this class.

    Generics:

    • K: The database unique identifier.
    • V: The value stored against K.
    • VK: The a value-derived key that will be used as a cache key when caching K for lookups by V. This can be the value itself if it is itself a good key.
    Since:
    3.2
    Author:
    Derek Hulley

    • Method Summary

      All Methods Instance Methods Concrete Methods 
      Modifier and Type Method Description
      void clear()
      Cache-only operation: Remove all cache entries
      org.alfresco.util.Pair<K,​V> createOrGetByValue​(V value, ControlDAO controlDAO)
      Attempt to create the entity and, failing that, look it up.
      This method takes the opposite approach to getOrCreateByValue(Object), which assumes the entity's existence: in this case the entity is assumed to NOT exist.
      int deleteByKey​(K key)
      Delete the entity associated with the given key.
      int deleteByValue​(V value)
      Delete the entity having the given value..
      org.alfresco.util.Pair<K,​V> getByKey​(K key)
      Find the entity associated with the given key.
      org.alfresco.util.Pair<K,​V> getByValue​(V value)
      Find the entity associated with the given value.
      K getKey​(VK valueKey)
      Cache-only operation: Get the key for a given value key (note: not 'value' but 'value key').
      org.alfresco.util.Pair<K,​V> getOrCreateByValue​(V value)
      Find the entity associated with the given value and create it if it doesn't exist.
      V getValue​(K key)
      Cache-only operation: Get the value for a given key
      void removeByKey​(K key)
      Cache-only operation: Remove all cache values associated with the given key.
      void removeByValue​(V value)
      Cache-only operation: Remove all cache values associated with the given value
      void setValue​(K key, V value)
      Cache-only operation: Update the cache's value
      int updateValue​(K key, V value)
      Update the entity associated with the given key.

      • Methods inherited from class java.lang.Object

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

    • Constructor Detail

      • EntityLookupCache

        public EntityLookupCache​(EntityLookupCache.EntityLookupCallbackDAO<K,​V,​VK> entityLookup)
        Construct the lookup cache without any cache. All calls are passed directly to the underlying DAO entity lookup.
        Parameters:
        entityLookup - the instance that is able to find and persist entities

      • EntityLookupCache

        public EntityLookupCache​(org.alfresco.repo.cache.SimpleCache cache,
                         EntityLookupCache.EntityLookupCallbackDAO<K,​V,​VK> entityLookup)
        Construct the lookup cache, using the default cache region.
        Parameters:
        cache - the cache that will back the two-way lookups
        entityLookup - the instance that is able to find and persist entities

      • EntityLookupCache

        public EntityLookupCache​(org.alfresco.repo.cache.SimpleCache cache,
                         java.lang.String cacheRegion,
                         EntityLookupCache.EntityLookupCallbackDAO<K,​V,​VK> entityLookup)
        Construct the lookup cache, using the given cache region.

        All keys will be unique to the given cache region, allowing the cache to be shared between instances of this class.

        Parameters:
        cache - the cache that will back the two-way lookups; null to have no backing in a cache.
        cacheRegion - the region within the cache to use.
        entityLookup - the instance that is able to find and persist entities

    • Method Detail

      • getByKey

        public org.alfresco.util.Pair<K,​V> getByKey​(K key)
        Find the entity associated with the given key. The entity callback will be used if necessary.

        It is up to the client code to decide if a null return value indicates a concurrency violation or not; the former would normally result in a concurrency-related exception such as ConcurrencyFailureException.

        Parameters:
        key - The entity key, which may be valid or invalid (null not allowed)
        Returns:
        Returns the key-value pair or null if the key doesn't reference an entity

      • getByValue

        public org.alfresco.util.Pair<K,​V> getByValue​(V value)
        Find the entity associated with the given value. The entity callback will be used if no entry exists in the cache.

        It is up to the client code to decide if a null return value indicates a concurrency violation or not; the former would normally result in a concurrency-related exception such as ConcurrencyFailureException.

        Parameters:
        value - The entity value, which may be valid or invalid (null is allowed)
        Returns:
        Returns the key-value pair or null if the value doesn't reference an entity

      • updateValue

        public int updateValue​(K key,
                       V value)
        Update the entity associated with the given key. The EntityLookupCache.EntityLookupCallbackDAO.updateValue(Serializable, Object) callback will be used if necessary.

        It is up to the client code to decide if a 0 return value indicates a concurrency violation or not; usually the former will generate ConcurrencyFailureException or something recognised by the RetryingTransactionHelper.

        Parameters:
        key - The entity key, which may be valid or invalid (null not allowed)
        value - The new entity value (may be null)
        Returns:
        Returns the row update count.

      • getKey

        public K getKey​(VK valueKey)
        Cache-only operation: Get the key for a given value key (note: not 'value' but 'value key').
        Parameters:
        valueKey - The entity value key, which must be valid (null not allowed)
        Returns:
        The entity key (may be null)

      • getValue

        public V getValue​(K key)
        Cache-only operation: Get the value for a given key
        Parameters:
        key - The entity key, which may be valid or invalid (null not allowed)
        Returns:
        The entity value (may be null)

      • setValue

        public void setValue​(K key,
                     V value)
        Cache-only operation: Update the cache's value
        Parameters:
        key - The entity key, which may be valid or invalid (null not allowed)
        value - The new entity value (may be null)

      • deleteByKey

        public int deleteByKey​(K key)
        Delete the entity associated with the given key. The EntityLookupCache.EntityLookupCallbackDAO.deleteByKey(Serializable) callback will be used if necessary.

        It is up to the client code to decide if a 0 return value indicates a concurrency violation or not; usually the former will generate ConcurrencyFailureException or something recognised by the RetryingTransactionHelper.

        Parameters:
        key - the entity key, which may be valid or invalid (null not allowed)
        Returns:
        Returns the row deletion count

      • deleteByValue

        public int deleteByValue​(V value)
        Delete the entity having the given value.. The EntityLookupCache.EntityLookupCallbackDAO.deleteByValue(Object) callback will be used if necessary.

        It is up to the client code to decide if a 0 return value indicates a concurrency violation or not; usually the former will generate ConcurrencyFailureException or something recognised by the RetryingTransactionHelper.

        Parameters:
        value - the entity value, which may be valid or invalid (null allowed)
        Returns:
        Returns the row deletion count

      • removeByKey

        public void removeByKey​(K key)
        Cache-only operation: Remove all cache values associated with the given key.

      • removeByValue

        public void removeByValue​(V value)
        Cache-only operation: Remove all cache values associated with the given value
        Parameters:
        value - The entity value (null is allowed)

      • clear

        public void clear()
        Cache-only operation: Remove all cache entries

        NOTE: This operation removes ALL entries for ALL cache regions.