com.antelmann.db
Interface DBReference

All Superinterfaces:

Serializable

All Known Implementing Classes:

DBDocument.Header, DefaultDBReference, EntryHeader, GPerson.Header, ImageURLEntry.Thumbnail, Stub

public interface DBReference
extends Serializable

DBReference represents an Object that can hold a reference to a DBEntry object, providing sufficient means to retrieve that object from a Database. Note that a DBReference may be 'empty', i.e. both, reference class and reference id are null.

Author:

Holger Antelmann

See Also:

Database, DBEntry, DBEntrySelection

Field Summary

static DataFlavor	REFERENCE_FLAVOR allows to transfer a DBReference instance
static DataFlavor	REFERENCE_LIST_FLAVOR allows to transfer an array of DBReference objects

Method Summary

Class<? extends DBEntry>	getReferenceClass() indicates the type of DBEntry that represents the class of the reference ID, so that the instance could be looked up in a Database; this may be null only if the reference itself is null, too.
Object	getReferenceID() returns the ID of the DBEntry this instance refers to; this may be null only if the reference type returns null, too.
String	getReferenceString() provides a meaningful (displayable) description for the referenceID/referenceType or null if there is no reference for this entry.

Field Detail

REFERENCE_FLAVOR

static final DataFlavor REFERENCE_FLAVOR

allows to transfer a DBReference instance

REFERENCE_LIST_FLAVOR

static final DataFlavor REFERENCE_LIST_FLAVOR

allows to transfer an array of DBReference objects

Method Detail

getReferenceID

Object getReferenceID()

returns the ID of the DBEntry this instance refers to; this may be null only if the reference type returns null, too.

See Also:

DBEntry.getID(), DefaultDBReference.isConsistent(DBReference)

getReferenceClass

Class<? extends DBEntry> getReferenceClass()

indicates the type of DBEntry that represents the class of the reference ID, so that the instance could be looked up in a Database; this may be null only if the reference itself is null, too.

See Also:

Database, DBEntry#getClass(), DefaultDBReference.isConsistent(DBReference)

getReferenceString

String getReferenceString()

provides a meaningful (displayable) description for the referenceID/referenceType or null if there is no reference for this entry. Normally, this method would provide some cached info about the reference w/o having to dereference the link through the database. Note that this method may return null even if the reference itself is not null.