com.googlecode.objectify.impl

Class PolymorphicEntityMetadata<T>

java.lang.Object

com.googlecode.objectify.impl.PolymorphicEntityMetadata<T>

All Implemented Interfaces:

EntityMetadata<T>

public class PolymorphicEntityMetadata<T>
extends Object
implements EntityMetadata<T>

The interface by which POJOs and datastore Entity objects are translated back and forth. Subclasses implement specific mapping, including polymorphic mapping.

Author:

Jeff Schnitzer

Field Summary

Fields

Modifier and Type	Field and Description
static String	DISCRIMINATOR_INDEX_PROPERTY Name of the list property which will hold all indexed discriminator values
static String	DISCRIMINATOR_PROPERTY Name of the out-of-band discriminator property in a raw Entity

Constructor Summary

Constructors

Constructor and Description
PolymorphicEntityMetadata(Class<T> clazz, ConcreteEntityMetadata<T> baseMetadata) Initializes this metadata structure with the specified class.

Method Summary

Methods

Modifier and Type	Method and Description
<S extends T> void	addSubclass(Class<S> clazz, ConcreteEntityMetadata<S> subclassMeta) Registers an @EntitySubclass in a polymorphic hierarchy.
Integer	getCacheExpirySeconds() Get the expiry associated with this kind, defined by the @Cached annotation.
Class<T>	getEntityClass() Gets the class associated with this entity.
KeyMetadata<T>	getKeyMetadata() Get specific metadata about the key for this type.
T	load(com.google.appengine.api.datastore.Entity ent, LoadContext ctx) Converts an entity to an object of the appropriate type for this metadata structure.
com.google.appengine.api.datastore.Entity	save(T pojo, SaveContext ctx) Converts an object to a datastore Entity with the appropriate Key type.

Methods inherited from class java.lang.Object

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

Field Detail

DISCRIMINATOR_PROPERTY

public static final String DISCRIMINATOR_PROPERTY

Name of the out-of-band discriminator property in a raw Entity

See Also:

Constant Field Values

DISCRIMINATOR_INDEX_PROPERTY

public static final String DISCRIMINATOR_INDEX_PROPERTY

Name of the list property which will hold all indexed discriminator values

See Also:

Constant Field Values

Constructor Detail

PolymorphicEntityMetadata

public PolymorphicEntityMetadata(Class<T> clazz,
                         ConcreteEntityMetadata<T> baseMetadata)

Initializes this metadata structure with the specified class.

Parameters:

baseMetadata - is the metadata for the @Entity class that defines the kind of the hierarchy

Method Detail

addSubclass

public <S extends T> void addSubclass(Class<S> clazz,
                             ConcreteEntityMetadata<S> subclassMeta)

Registers an @EntitySubclass in a polymorphic hierarchy.

Parameters:

clazz - must have the @EntitySubclass annotation

getCacheExpirySeconds

public Integer getCacheExpirySeconds()

Description copied from interface: EntityMetadata

Get the expiry associated with this kind, defined by the @Cached annotation. For polymorphic types, this is always the instruction on the root @Entity - you cannot provide per-type caching.

Specified by:

getCacheExpirySeconds in interface EntityMetadata<T>

Returns:

null means DO NOT CACHE, 0 means "no limit", otherwise # of seconds

load

public T load(com.google.appengine.api.datastore.Entity ent,
     LoadContext ctx)

Description copied from interface: EntityMetadata

Converts an entity to an object of the appropriate type for this metadata structure. Does not check that the entity is appropriate; that should be done when choosing which EntityMetadata to call.

Specified by:

load in interface EntityMetadata<T>

save

public com.google.appengine.api.datastore.Entity save(T pojo,
                                             SaveContext ctx)

Description copied from interface: EntityMetadata

Converts an object to a datastore Entity with the appropriate Key type.

Specified by:

save in interface EntityMetadata<T>

getKeyMetadata

public KeyMetadata<T> getKeyMetadata()

Description copied from interface: EntityMetadata

Get specific metadata about the key for this type.

Specified by:

getKeyMetadata in interface EntityMetadata<T>

getEntityClass

public Class<T> getEntityClass()

Description copied from interface: EntityMetadata

Gets the class associated with this entity.

Specified by:

getEntityClass in interface EntityMetadata<T>