.. java:import:: java.util HashMap

.. java:import:: java.util LinkedList

.. java:import:: java.util List

.. java:import:: org.apache.commons.jcs.access.behavior ICacheAccess

.. java:import:: org.caosdb.server.caching Cache

.. java:import:: org.caosdb.server.database CacheableBackendTransaction

.. java:import:: org.caosdb.server.database.backend.interfaces RetrieveVersionHistoryImpl

.. java:import:: org.caosdb.server.database.exceptions TransactionException

.. java:import:: org.caosdb.server.database.proto VersionHistoryItem

.. java:import:: org.caosdb.server.entity EntityID

.. java:import:: org.caosdb.server.entity EntityInterface

.. java:import:: org.caosdb.server.entity Version

VersionTransaction
==================

.. java:package:: org.caosdb.server.database.backend.transaction
   :noindex:

.. java:type:: public abstract class VersionTransaction extends CacheableBackendTransaction<EntityID, HashMap<String, VersionHistoryItem>>

   Abstract base class which retrieves and caches the full, but flat version history. The implementations then use the flat version history to construct either single version information items (see \ :java:ref:`RetrieveVersionInfo`\ ) or the complete history as a tree (see \ :java:ref:`RetrieveVersionHistory`\ )

   :author: Timm Fitschen (t.fitschen@indiscale.com)

Constructors
------------
VersionTransaction
^^^^^^^^^^^^^^^^^^

.. java:constructor:: public VersionTransaction(EntityInterface e)
   :outertype: VersionTransaction

Methods
-------
executeNoCache
^^^^^^^^^^^^^^

.. java:method:: @Override public HashMap<String, VersionHistoryItem> executeNoCache() throws TransactionException
   :outertype: VersionTransaction

getEntity
^^^^^^^^^

.. java:method:: public EntityInterface getEntity()
   :outertype: VersionTransaction

getHistoryItems
^^^^^^^^^^^^^^^

.. java:method:: public HashMap<String, VersionHistoryItem> getHistoryItems()
   :outertype: VersionTransaction

getKey
^^^^^^

.. java:method:: @Override protected EntityID getKey()
   :outertype: VersionTransaction

getPredecessors
^^^^^^^^^^^^^^^

.. java:method:: protected List<Version> getPredecessors(String versionId, boolean transitive)
   :outertype: VersionTransaction

   Return a list of direct predecessors. The predecessors are constructed by \ :java:ref:`getVersion(String)`\ .

   If transitive is true, this function is called recursively on the predecessors as well, resulting in a list of trees of predecessors, with the direct predecessors at the root(s).

   :param versionId:
   :param transitive:
   :return: A list of predecessors.

getSuccessors
^^^^^^^^^^^^^

.. java:method:: protected List<Version> getSuccessors(String versionId, boolean transitive)
   :outertype: VersionTransaction

   Return a list of direct successors. The successors are constructed by \ :java:ref:`getVersion(String)`\ .

   If transitive is true, this function is called recursively on the successors as well, resulting in a list of trees of successors, with the direct successors at the root(s).

   :param versionId:
   :param transitive:
   :return: A list of successors.

getVersion
^^^^^^^^^^

.. java:method:: protected abstract Version getVersion(String versionId)
   :outertype: VersionTransaction

   To be implemented by the base class. The idea is, that the base class decides which information is being included into the Version instance.

   :param versionId: - the id of the version

process
^^^^^^^

.. java:method:: @Override protected void process(HashMap<String, VersionHistoryItem> historyItems) throws TransactionException
   :outertype: VersionTransaction

   After this method call, the version map is available to the object.

removeCached
^^^^^^^^^^^^

.. java:method:: public static void removeCached(EntityID entityId)
   :outertype: VersionTransaction

   Invalidate a cache item. This should be called upon update of entities.

   :param entityId: