Package com.googlecode.objectify.impl.translate

Class EntityTranslator

java.lang.Object

com.googlecode.objectify.impl.translate.EntityTranslator

All Implemented Interfaces:

Translator<Object,com.google.appengine.api.datastore.PropertyContainer>

public class EntityTranslator
extends Object
implements Translator<Object,com.google.appengine.api.datastore.PropertyContainer>

Translator which can translate arbitrary entities based on registered kinds. This provides a layer of indirection, and allows you to store heterogeneous collections.

Author:

Jeff Schnitzer

Constructor Summary

Constructors

Constructor	Description
EntityTranslator(Registrar registrar)

Method Summary

Modifier and Type	Method	Description
Object	load(com.google.appengine.api.datastore.PropertyContainer container, LoadContext ctx, Path path)	Loads the content of the specified datastore node, returning the pojo equivalent.
com.google.appengine.api.datastore.PropertyContainer	save(Object pojo, boolean index, SaveContext ctx, Path path)	Translates a pojo (or some component thereof) into a format suitable for storage in the datastore.

Methods inherited from class java.lang.Object

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

Constructor Details

EntityTranslator

public EntityTranslator(Registrar registrar)

Method Details

load

public Object load(com.google.appengine.api.datastore.PropertyContainer container,
 LoadContext ctx,
 Path path)
            throws SkipException

Description copied from interface: Translator

Loads the content of the specified datastore node, returning the pojo equivalent.

There is one special return value: If a Result is returned, the content of the Result will be used instead, but delayed until ctx.done() is called. This happens at the end of a "round" of load operations and is the magic trick that makes populating entity references work efficiently.

Specified by:

load in interface Translator<Object,com.google.appengine.api.datastore.PropertyContainer>

Parameters:

container - is the part of the native datastore entity tree we are transforming.

ctx - holds state information during an entity load.

path - is the current path to this translator

Returns:

an assembled pojo corresponding to the node subtree; if null is returned, that is the real value!

Throws:

SkipException - if the return value should be abandoned.

See Also:

LoadEngine

save

public com.google.appengine.api.datastore.PropertyContainer save(Object pojo,
 boolean index,
 SaveContext ctx,
 Path path)
                                                          throws SkipException

Description copied from interface: Translator

Translates a pojo (or some component thereof) into a format suitable for storage in the datastore.

Specified by:

save in interface Translator<Object,com.google.appengine.api.datastore.PropertyContainer>

Parameters:

pojo - is an object from the pojo entity graph; possibly the whole graph or possibly just a leaf field.

index - is whether the instruction so far is to index or not index property values

path - is the path that we have taken to get here, which could be long due to re-entrant translators (ie, an embedded pojo that also has a reference to the same class).

Returns:

something suitable for storage in the datastore.

Throws:

SkipException - if the return value should be abandoned