com.db4o.ext

Interface StoredField

All Known Implementing Classes:

CommitTimestampFieldMetadata, FieldMetadata, NullFieldMetadata, StoredFieldImpl, TranslatedAspect, UnknownTypeHandlerAspect, UUIDFieldMetadata, VersionFieldMetadata, VirtualFieldMetadata

public interface StoredField

the internal representation of a field on a stored class.

Method Summary

Methods

Modifier and Type	Method and Description
void	createIndex() creates an index on this field at runtime.
void	dropIndex() drops an existing index on this field at runtime.
java.lang.Object	get(java.lang.Object onObject) returns the field value on the passed object.
java.lang.String	getName() returns the name of the field.
ReflectClass	getStoredType() returns the Class (Java) / Type (.NET) of the field.
boolean	hasIndex() Returns whether this field has an index or not.
boolean	isArray() returns true if the field is an array.
void	rename(java.lang.String name) modifies the name of this stored field.
void	traverseValues(Visitor4 visitor) specialized highspeed API to collect all values of a field for all instances of a class, if the field is indexed.

Method Detail

createIndex

void createIndex()

creates an index on this field at runtime.

dropIndex

void dropIndex()

drops an existing index on this field at runtime.

get

java.lang.Object get(java.lang.Object onObject)

returns the field value on the passed object.

This method will also work, if the field is not present in the current version of the class.

It is recommended to use this method for refactoring purposes, if fields are removed and the field values need to be copied to other fields.

getName

java.lang.String getName()

returns the name of the field.

getStoredType

ReflectClass getStoredType()

returns the Class (Java) / Type (.NET) of the field.

For array fields this method will return the type of the array. Use isArray() to detect arrays.

isArray

boolean isArray()

returns true if the field is an array.

rename

void rename(java.lang.String name)

modifies the name of this stored field.

After renaming one or multiple fields the ObjectContainer has to be closed and reopened to allow internal caches to be refreshed.

Parameters:

name - the new name

traverseValues

void traverseValues(Visitor4 visitor)

specialized highspeed API to collect all values of a field for all instances of a class, if the field is indexed.

The field values will be taken directly from the index without the detour through class indexes or object instantiation.

If this method is used to get the values of a first class object index, deactivated objects will be passed to the visitor.

Parameters:

visitor - the visitor to be called with each index value.

hasIndex

boolean hasIndex()

Returns whether this field has an index or not.

Returns:

true if this field has an index.