Class MemoryEfficientLazyEntityList

java.lang.Object

ch.tocco.nice2.persist.core.api.entity.AbstractEntityList

ch.tocco.nice2.persist.core.api.hibernate.AbstractLazyEntityList

ch.tocco.nice2.persist.core.api.hibernate.MemoryEfficientLazyEntityList

All Implemented Interfaces:

EntityList, AutoCloseable, Iterable<Entity>

public class MemoryEfficientLazyEntityList
extends AbstractLazyEntityList
implements AutoCloseable

An implementation of EntityList that loads the entities in batches (similar to LazyEntityList), but uses a new Context for every page. When a new page is loaded, the old Context of the previous page will be closed. This implementation is efficient when the data is accessed in the order of the list. It's very inefficient if the elements are accessed randomly. In addition, entities should only be used within the loop, because not all operations are supported when the is closed.

Nested Class Summary

Nested classes/interfaces inherited from class AbstractEntityList

AbstractEntityList.SimpleIterator

Nested classes/interfaces inherited from interface EntityList

EntityList.Filter

Field Summary

Fields inherited from class AbstractLazyEntityList

keys, pageSize

Constructor Summary

Constructors

Constructor	Description
MemoryEfficientLazyEntityList(ContextManager contextManager, PrimaryKeyList keys)

Method Summary

Modifier and Type	Method	Description
void	close()
protected void	contextCreated(Context context)
Entity	get(int index, boolean eager)	Get the entity at the specified index.
Entity	getFirstEntity()
EntityManager	getManager()	Get the entity manager.
List<Entity>	toList()	Calling toList() will lose the memory management functionality, so we just load all entities from the thread context.

Methods inherited from class AbstractLazyEntityList

getKey, getKeys, getModel, getPageCount, getPageForIndex, getPageSize, indexOf, setPageSize, size, unwrap

Methods inherited from class AbstractEntityList

contains, expect, expectAtLeast, expectAtMost, get, get, get, isEmpty, iterator, toList

Methods inherited from class Object

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

Methods inherited from interface EntityList

doWithSingleResult, doWithSingleResultOr, expectAtMostOrThrow, expectOr, expectOrThrow, getOnlyResult, getOptionalOnlyResult, getOptionalOnlyResult, requireFirstEntity, spliterator, stream

Methods inherited from interface Iterable

forEach

Constructor Details

MemoryEfficientLazyEntityList

public MemoryEfficientLazyEntityList(ContextManager contextManager,
 PrimaryKeyList keys)

Method Details

get

public Entity get(int index,
 boolean eager)
           throws PersistException

Description copied from interface: EntityList

Get the entity at the specified index.

Specified by:

get in interface EntityList

Parameters:

index - The index.

eager - true, if a page should be eagerly loaded, if the entity's state is hollow, false otherwise.

Returns:

The entity at the specified index potentially in unusable state, or null.

Throws:

PersistException

getManager

public EntityManager getManager()

Description copied from interface: EntityList

Get the entity manager.

Specified by:

getManager in interface EntityList

Returns:

The entity manager.

getFirstEntity

public Entity getFirstEntity()

Specified by:

getFirstEntity in interface EntityList

Returns:

the first entity or null

toList

public List<Entity> toList()

Calling toList() will lose the memory management functionality, so we just load all entities from the thread context.

Specified by:

toList in interface EntityList

Overrides:

toList in class AbstractEntityList

contextCreated

protected void contextCreated(Context context)

close

public void close()

Specified by:

close in interface AutoCloseable