org.eclipse.persistence.queries

Class LoadGroup

java.lang.Object

org.eclipse.persistence.core.queries.CoreAttributeGroup<org.eclipse.persistence.internal.queries.AttributeItem,ClassDescriptor>

org.eclipse.persistence.queries.AttributeGroup

org.eclipse.persistence.queries.LoadGroup

All Implemented Interfaces:

java.io.Serializable, java.lang.Cloneable

public class LoadGroup
extends AttributeGroup

Purpose: Used to load specified relationship attributes and nested relationship attributes.

A LoadGroup can be configured for use on a query using ObjectLevelReadQuery.setLoadGroup(LoadGroup) or in the case of JPA users with LOAD_GROUP query hint. Alternatively a FetchGroup could be used with FetchGroup.shouldLoad() set to true and the FetchGroup configured on a query be executed.

See Also:

FetchGroup, Serialized Form

Author:

ailitchev

Since:

Eclipselink 2.1

Field Summary

Fields

Modifier and Type	Field and Description
protected java.lang.Boolean	isConcurrent

Fields inherited from class org.eclipse.persistence.core.queries.CoreAttributeGroup

allsubclasses, isValidated, items, name, subClasses, superClassGroup, type, typeName

Constructor Summary

Constructors

Constructor and Description
LoadGroup()
LoadGroup(java.lang.String name)

Method Summary

Modifier and Type	Method and Description
void	addAttribute(java.lang.String attributeNameOrPath, CoreAttributeGroup group) Add a basic attribute or nested attribute with each String representing an attribute on the path to what needs to be included in the AttributeGroup.
void	addAttribute(java.lang.String attributeNameOrPath, LoadGroup group)
LoadGroup	clone()
LoadGroup	getGroup(java.lang.String attributeNameOrPath) Returns LoadGroup corresponding to the passed (possibly nested) attribute.
java.lang.Boolean	getIsConcurrent() INTERNAL: Return if the load group should load its relationships concurrently.
boolean	isConcurrent() ADVANCED: Return if the load group should load its relationships concurrently.
boolean	isLoadGroup()
protected LoadGroup	newGroup(java.lang.String name, CoreAttributeGroup parent) Subclass may create different types.
void	setIsConcurrent(java.lang.Boolean isConcurrent) ADVANCED: Set if the load group should load its relationships concurrently.

Methods inherited from class org.eclipse.persistence.queries.AttributeGroup

addAttribute, findGroup, getItem, isCopyGroup, isSupersetOf, newItem, newItem, toCopyGroup, toCopyGroup, toFetchGroup, toFetchGroup, toLoadGroup, toLoadGroup

Methods inherited from class org.eclipse.persistence.core.queries.CoreAttributeGroup

addAttribute, addAttribute, addAttributeKey, addAttributes, clone, containsAttribute, containsAttributeInternal, convert, convertClassNamesToClasses, equals, getAllItems, getAttributeNames, getItem, getItems, getName, getSubClassGroups, getType, getTypeName, hasInheritance, hasItems, insertSubClass, isFetchGroup, isSupersetOf, isValidated, removeAttribute, setAllSubclasses, setAttributeNames, setName, toString, toStringAdditionalInfo, toStringItems, toStringPath

Methods inherited from class java.lang.Object

finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait

Field Detail

isConcurrent

protected java.lang.Boolean isConcurrent

Constructor Detail

LoadGroup

public LoadGroup()

LoadGroup

public LoadGroup(java.lang.String name)

Method Detail

newGroup

protected LoadGroup newGroup(java.lang.String name,
                             CoreAttributeGroup parent)

Description copied from class: AttributeGroup

Subclass may create different types.

Overrides:

newGroup in class AttributeGroup

isLoadGroup

public boolean isLoadGroup()

Overrides:

isLoadGroup in class AttributeGroup

clone

public LoadGroup clone()

Overrides:

clone in class AttributeGroup

getGroup

public LoadGroup getGroup(java.lang.String attributeNameOrPath)

Returns LoadGroup corresponding to the passed (possibly nested) attribute.

Overrides:

getGroup in class AttributeGroup

addAttribute

public void addAttribute(java.lang.String attributeNameOrPath,
                         CoreAttributeGroup group)

Description copied from class: CoreAttributeGroup

Add a basic attribute or nested attribute with each String representing an attribute on the path to what needs to be included in the AttributeGroup.

Example: group.addAttribute("firstName", group1);
group.addAttribute("manager.address", group2); Note that existing group corresponding to attributeNameOrPath will be overridden with the passed group.

Overrides:

addAttribute in class CoreAttributeGroup<org.eclipse.persistence.internal.queries.AttributeItem,ClassDescriptor>

Parameters:

attributeNameOrPath - A simple attribute, array or attributes forming a path

group - - an AttributeGroup to be added.

addAttribute

public void addAttribute(java.lang.String attributeNameOrPath,
                         LoadGroup group)

getIsConcurrent

public java.lang.Boolean getIsConcurrent()

INTERNAL: Return if the load group should load its relationships concurrently.

isConcurrent

public boolean isConcurrent()

ADVANCED: Return if the load group should load its relationships concurrently. This will use the session's server platform's thread pool. Each of the query results objects relationships will be loaded on a different thread. This can improve performance by processing many queries at once. Concurrent load is only supported when a shared cache is used.

Overrides:

isConcurrent in class AttributeGroup

setIsConcurrent

public void setIsConcurrent(java.lang.Boolean isConcurrent)

ADVANCED: Set if the load group should load its relationships concurrently. This will use the session's server platform's thread pool. Each of the query results objects relationships will be loaded on a different thread. This can improve performance by processing many queries at once. Concurrent load is only supported when a shared cache is used.