Class ProcedureCache

Method Details

• get

  public Object get(String key)

  Retrieves a ProcEntry object from the cache.

  If the entry exists it is moved to the front of the linked list to keep it alive as long as possible.

  Specified by:

  get in interface StatementCache

  Parameters:

  key - the key value identifying the required entry

  Returns:

  the keyed entry as an Object or null if the entry does not exist

• put

  public void put(String key, Object handle)

  Inserts a new entry, identified by a key, into the cache.

  If the cache is full then one or more entries are removed and transferred to a list for later destruction.

  Specified by:

  put in interface StatementCache

  Parameters:

  key - value used to identify the entry

  handle - proc entry to be inserted into the cache

• remove

  public void remove(String key)

  Removes a redundant entry from the cache.

  Specified by:

  remove in interface StatementCache

  Parameters:

  key - value that identifies the cache entry

• getObsoleteHandles

  public Collection getObsoleteHandles(Collection handles)

  Obtains a list of statement handles or procedures that can now be dropped.

  Specified by:

  getObsoleteHandles in interface StatementCache

  Parameters:

  handles - a collection of single use statements that will be returned for dropping if the cache is disabled

  Returns:

  the collection of redundant statments for dropping

• scavengeCache

  private void scavengeCache()

  Removes unused entries trying to bring down the cache to the requested size. The removed entries are placed in the free list.

  Note: entries that are in use will not be removed so it is possible for the cache to still be larger than cacheSize after the call finishes.