com.googlecode.objectify.impl.ref

Class LiveRef<T>

java.lang.Object

com.googlecode.objectify.Ref<T>

com.googlecode.objectify.impl.ref.LiveRef<T>

All Implemented Interfaces:

Serializable, Comparable<Ref<T>>

public class LiveRef<T>
extends Ref<T>

Implementation of Refs which are "live" and connected to the datastore so they can fetch entity values even if they have not already been loaded. This is the standard Ref implementation.

Author:

Jeff Schnitzer

See Also:

Serialized Form

Field Summary

Fields

Modifier and Type	Field and Description
protected Objectify	ofy So that Refs can be associated with a session

Fields inherited from class com.googlecode.objectify.Ref

key

Constructor Summary

Constructors

Modifier	Constructor and Description
protected	LiveRef() For GWT serialization
	LiveRef(Key<T> key) Create a Ref based on the key
	LiveRef(Key<T> key, Objectify ofy) Create a Ref based on the key, with the specified session

Method Summary

Modifier and Type	Method and Description
T	get() Obtain the entity value associated with the key.
boolean	isLoaded() If an entity has been loaded into the session or is otherwise available, this will return true.
protected Object	writeReplace() When this serializes, write out the DeadRef version.

Methods inherited from class com.googlecode.objectify.Ref

compareTo, create, create, equals, equivalent, equivalent, getKey, getValue, hashCode, key, safe, toString

Methods inherited from class java.lang.Object

clone, finalize, getClass, notify, notifyAll, wait, wait, wait

Field Detail

ofy

protected transient Objectify ofy

So that Refs can be associated with a session

Constructor Detail

LiveRef

protected LiveRef()

For GWT serialization

LiveRef

public LiveRef(Key<T> key)

Create a Ref based on the key

LiveRef

public LiveRef(Key<T> key,
               Objectify ofy)

Create a Ref based on the key, with the specified session

Method Detail

get

public T get()

Description copied from class: Ref

Obtain the entity value associated with the key. Will pull from session if present, otherwise will fetch from the datastore.

Specified by:

get in class Ref<T>

Returns:

the entity referenced, or null if the entity was not found

isLoaded

public boolean isLoaded()

Description copied from class: Ref

If an entity has been loaded into the session or is otherwise available, this will return true. Calls to get() will not require a trip to backing store. Note that even when loaded, get() can still return null if there is no entity which corresponds to the key.

Specified by:

isLoaded in class Ref<T>

Returns:

true if the value is in the session or otherwise immediately available; false if get() will require a trip to the datastore or memcache.

writeReplace

protected Object writeReplace()
                       throws ObjectStreamException

When this serializes, write out the DeadRef version. Use the getValue() for value so that if the value is not loaded, it serializes as null.

Throws:

ObjectStreamException