public JDBCOptimisticLockingMetaData(JDBCEntityMetaData entityMetaData,
    Element element) throws DeploymentException 
{
   // Constructors ------------------------------------
      log = Logger.getLogger(entityMetaData.getName());
      Element strategyEl;
      if((strategyEl = MetaData.getOptionalChild(element, "group-name")) != null)
      {
         lockingStrategy = FIELD_GROUP_STRATEGY;
         groupName = MetaData.getElementContent(strategyEl);
         lockingField = null;
         keyGeneratorFactory = null;
         log.debug("optimistic locking: group=" + groupName);
      }
      else if((strategyEl = MetaData.getOptionalChild(element, "modified-strategy")) != null)
      {
         lockingStrategy = MODIFIED_STRATEGY;
         groupName = null;
         lockingField = null;
         keyGeneratorFactory = null;
         log.debug("optimistic locking: modified strategy");
      }
      else if((strategyEl = MetaData.getOptionalChild(element, "read-strategy")) != null)
      {
         lockingStrategy = READ_STRATEGY;
         groupName = null;
         lockingField = null;
         keyGeneratorFactory = null;
         log.debug("optimistic locking: read strategy");
      }
      else if((strategyEl = MetaData.getOptionalChild(element, "version-column")) != null)
      {
         String fieldType = MetaData.getOptionalChildContent(element, "field-type");
         if(fieldType != null)
            throw new DeploymentException(
               "field-type is not allowed for version column. It is implicitly set to java.lang.Long."
            );
         lockingStrategy = VERSION_COLUMN_STRATEGY;
         lockingField = constructLockingField(entityMetaData, element);
         groupName = null;
         keyGeneratorFactory = null;
         log.debug("optimistic locking: version-column=" + lockingField.getFieldName());
      }
      else if((strategyEl = MetaData.getOptionalChild(element, "timestamp-column")) != null)
      {
         String fieldType = MetaData.getOptionalChildContent(element, "field-type");
         if(fieldType != null)
            throw new DeploymentException(
               "field-type is not allowed for timestamp column. It is implicitly set to java.util.Date."
            );
         lockingStrategy = TIMESTAMP_COLUMN_STRATEGY;
         lockingField = constructLockingField(entityMetaData, element);
         groupName = null;
         keyGeneratorFactory = null;
         log.debug("optimistic locking: timestamp-column=" + lockingField.getFieldName());
      }
      else if((keyGeneratorFactory =
         MetaData.getOptionalChildContent(element, "key-generator-factory")) != null)
      {
         lockingStrategy = KEYGENERATOR_COLUMN_STRATEGY;
         lockingField = constructLockingField(entityMetaData, element);
         groupName = null;
         log.debug("optimistic locking: key-generator-factory=" + keyGeneratorFactory);
      }
      else
      {
         throw new DeploymentException("Unexpected error: entity "
            + entityMetaData.getName()
            + " has unkown/incorrect optimistic locking configuration.");
      }
}

Constructs optimistic locking metadata reading optimistic-locking XML element

 public String getGroupName() 
{
      return groupName;
}

 public String getKeyGeneratorFactory() 
{
      return keyGeneratorFactory;
}

 public JDBCCMPFieldMetaData getLockingField() 
{
      return lockingField;
}

 public Integer getLockingStrategy() 
{
      return lockingStrategy;
}