oracle.toplink.queryframework
Class FetchGroup

java.lang.Object
oracle.toplink.queryframework.FetchGroup

All Implemented Interfaces:

java.io.Serializable

public class FetchGroup

extends java.lang.Object

implements java.io.Serializable

Purpose: A fetch group is a performance enhancement that allows a group of attributes of an object to be loaded on demand, which means that the data for an attribute might not loaded from the underlying data source until an explicit access call for the attribute first occurs. It avoids the wasteful practice of loading up all data of the object?s attributes, in which the user is interested in only partial of them. A great deal of caution and careful system use case analysis should be use when using the fetch group feature, as the extra round-trip would well offset the gain from the deferred loading in many cases. TopLink fetch group support is twofold: the pre-defined fetch groups at the descriptor level; and dynamic (use case) fetch groups at the query level. TopLink fetch group support is only on CMP project. Every query can has at most one fetch group. There is an optional pre-defined default fetch group at the descriptor level. If set, and the query has no fetch group being set, the default fetch group would be used, unless query.setShouldUseDefaultFetchGroup(false) is also called. In the latter case, the full object will be fetched after the query execution.

Since:

TopLink 10.1.3.

See Also:

FetchGroup, FetchGroupTracker, Serialized Form

Constructor Summary

FetchGroup()
Constructor.

FetchGroup(java.lang.String name)
Constructor with a group name.

Method Summary

void	addAttribute(java.lang.String attrName) Add an attribute to the group
void	addAttributes(java.util.Set newAttributes) Add a set of attributes to the group
java.util.Set	getAttributes() Return all attributes defined in the group
java.lang.String	getName() Return the group name
void	removeAttribute(java.lang.String attrName) Remove an attribute from the group
void	setName(java.lang.String name) Set the group name

Methods inherited from class java.lang.Object

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

Constructor Detail

FetchGroup

public FetchGroup()

Constructor.

FetchGroup

public FetchGroup(java.lang.String name)

Constructor with a group name.

Method Detail

getAttributes

public java.util.Set getAttributes()

Return all attributes defined in the group

addAttribute

public void addAttribute(java.lang.String attrName)

Add an attribute to the group

addAttributes

public void addAttributes(java.util.Set newAttributes)

Add a set of attributes to the group

removeAttribute

public void removeAttribute(java.lang.String attrName)

Remove an attribute from the group

getName

public java.lang.String getName()

Return the group name

setName

public void setName(java.lang.String name)

Set the group name