org.datanucleus.store.db4o
Class DB4OExtent

java.lang.Object
  org.datanucleus.store.AbstractExtent
      org.datanucleus.store.db4o.DB4OExtent

All Implemented Interfaces:

org.datanucleus.store.Extent

public class DB4OExtent
extends org.datanucleus.store.AbstractExtent

Extent for use with DB4O datastores. The Extent is generated in two ways :-

• with subclasses - Use a simple candidate query in DB4O
• without subclasses - Use a SODA query to eliminate subclasses in DB4O

Nested Class Summary

class

DB4OExtent.DB4OExtentIterator Iterator for use with DB4O Extents.

Field Summary

protected static org.datanucleus.util.Localiser

LOCALISER_DB4O Localiser for messages.

Fields inherited from class org.datanucleus.store.AbstractExtent

candidateClass, cmd, ec, LOCALISER, subclasses

Constructor Summary

DB4OExtent(DB4OStoreManager storeMgr, org.datanucleus.store.ExecutionContext ec, java.lang.Class cls, boolean subclasses, org.datanucleus.metadata.AbstractClassMetaData cmd)
Constructor.

Method Summary

void	close(java.util.Iterator iter) Method to close the extent.
void	closeAll() Close all Iterators associated with this Extent instance.
org.datanucleus.FetchPlan	getFetchPlan() This method retrieves the fetch plan associated with the Extent.
java.util.Iterator	iterator() Returns an iterator over all the instances in the Extent.

Methods inherited from class org.datanucleus.store.AbstractExtent

getCandidateClass, getExecutionContext, hasSubclasses, toString

Methods inherited from class java.lang.Object

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

Field Detail

LOCALISER_DB4O

protected static final org.datanucleus.util.Localiser LOCALISER_DB4O

Localiser for messages.

Constructor Detail

DB4OExtent

public DB4OExtent(DB4OStoreManager storeMgr,
                  org.datanucleus.store.ExecutionContext ec,
                  java.lang.Class cls,
                  boolean subclasses,
                  org.datanucleus.metadata.AbstractClassMetaData cmd)

Constructor.

Parameters:

storeMgr - DB4OStoreManager

ec - execution context

cls - candidate class

subclasses - Whether to include subclasses

cmd - MetaData for the candidate class

Method Detail

close

public void close(java.util.Iterator iter)

Method to close the extent.

Parameters:

iter - an iterator obtained by the method iterator() on this Extent instance.

closeAll

public void closeAll()

Close all Iterators associated with this Extent instance. Iterators closed by this method will return false to hasNext() and will throw NoSuchElementException on next(). The Extent instance can still be used as a parameter of Query.setCandidates, and to get an Iterator.

iterator

public java.util.Iterator iterator()

Returns an iterator over all the instances in the Extent.

Returns:

an iterator over all the instances in the Extent.

getFetchPlan

public org.datanucleus.FetchPlan getFetchPlan()

This method retrieves the fetch plan associated with the Extent. It always returns the identical instance for the same Extent instance. Any change made to the fetch plan affects subsequent instance retrievals via next(). Only instances not already in memory are affected by the fetch plan. Fetch plan is described in Section 12.7.

Returns:

the FetchPlan