Class SPSNameCacheable

java.lang.Object
org.apache.derby.impl.sql.catalog.SPSNameCacheable
All Implemented Interfaces:
Cacheable
class SPSNameCacheable extends Object implements Cacheable
This class implements a Cacheable for a DataDictionary cache of sps descriptors, with the lookup key being the name/schema of the sps. Assumes client passes in a string that includes the schema name.

The cache ensures that the class of the target sps is loaded if the sps is found in cache. This is ensured by calling loadGeneratedClass() on the sps when it is added to the cache. Each subsequent user of the sps cache will do its own load/unload on the class. Because the class manager/loader maintains reference counts on the classes it is handling, the user load/unload will just increment/decrement the use count. Only when the sps is uncached will it be unloaded.

  • Field Details

  • Constructor Details

  • Method Details

    • clearIdentity

      public void clearIdentity()
      Description copied from interface: Cacheable
      Put the object into the No Identity state.
      MT - single thread required - Method must only be called be cache manager and the cache manager will guarantee only one thread can be calling it.
      Specified by:
      clearIdentity in interface Cacheable
      See Also:

    • getIdentity

      public Object getIdentity()
      Description copied from interface: Cacheable
      Get the identity of this object.
      MT - thread safe.
      Specified by:
      getIdentity in interface Cacheable
      See Also:

    • createIdentity

      public Cacheable createIdentity(Object key, Object createParameter)
      Description copied from interface: Cacheable
      Create a new item.

      Create a new item and set the identity of the object to represent it. The object will be in the No Identity state, ie. it will have just been created or clearIdentity() was just called.
      The object must copy the information out of key, not just store a reference to key if the key is not immutable. After this call the expression getIdentity().equals(key) must return true.

      If the class of the object needs to change (e.g. to support a different format) then the object should create a new object, call its initParameter() with the parameters the original object was called with, set its identity and return a reference to it. The cache manager will discard the reference to the old object.
      If an exception is thrown the object must be left in the no-identity state.
      MT - single thread required - Method must only be called be cache manager and the cache manager will guarantee only one thread can be calling it.

      Specified by:
      createIdentity in interface Cacheable
      Returns:
      an object reference if the object can take on the identity, null otherwise.
      See Also:

    • setIdentity

      public Cacheable setIdentity(Object key) throws StandardException
      Description copied from interface: Cacheable
      Set the identity of the object.

      Set the identity of the object to represent an item that already exists, e.g. an existing container. The object will be in the No Identity state, ie. it will have just been created or clearIdentity() was just called.
      The object must copy the information out of key, not just store a reference to key. After this call the expression getIdentity().equals(key) must return true.
      If the class of the object needs to change (e.g. to support a different format) then the object should create a new object, call its initParameter() with the parameters the original object was called with, set its identity and return a reference to it. The cache manager will discard the reference to the old object.
      If an exception is thrown the object must be left in the no-identity state.
      MT - single thread required - Method must only be called be cache manager and the cache manager will guarantee only one thread can be calling it.

      Specified by:
      setIdentity in interface Cacheable
      Returns:
      an object reference if the object can take on the identity, null otherwise.
      Throws:
      StandardException - Thrown on error
      See Also:

    • clean

      public void clean(boolean forRemove)
      Description copied from interface: Cacheable
      Clean the object. It is up to the object to ensure synchronization of the isDirty() and clean() method calls.
      If forRemove is true then the object is being removed due to an explict remove request, in this case the cache manager will have called this method regardless of the state of the isDirty()
      If an exception is thrown the object must be left in the clean state.
      MT - thread safe - Can be called at any time by the cache manager, it is the responsibility of the object implementing Cacheable to ensure any users of the object do not conflict with the clean call.
      Specified by:
      clean in interface Cacheable
      See Also:

    • isDirty

      public boolean isDirty()
      Description copied from interface: Cacheable
      Returns true of the object is dirty. May be called when the object is kept or unkept.
      MT - thread safe
      Specified by:
      isDirty in interface Cacheable
      See Also:

    • getSPSDescriptor

      public SPSDescriptor getSPSDescriptor()
      Get the sps descriptor that is associated with this Cacheable