Package com.googlecode.objectify.impl.translate

Class ClassPopulator<P>

java.lang.Object

com.googlecode.objectify.impl.translate.ClassPopulator<P>

All Implemented Interfaces:

Populator<P>

public class ClassPopulator<P>
extends Object
implements Populator<P>

Used by translators to populate properties between POJO and PropertiesContainer. Unlike translators, this does not create the POJO or container, it just copies translated properties between them.

Always excludes the key fields, @Id and @Parent.

Author:

Jeff Schnitzer

Constructor Summary

Constructors

Constructor	Description
ClassPopulator(Class<P> clazz, CreateContext ctx, Path path)

Method Summary

Modifier and Type	Method	Description
void	load(com.google.appengine.api.datastore.PropertyContainer node, LoadContext ctx, Path path, P into)	Loads the content of the specified datastore node, returning the pojo equivalent.
void	save(P pojo, boolean index, SaveContext ctx, Path path, com.google.appengine.api.datastore.PropertyContainer into)	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 Detail

ClassPopulator

public ClassPopulator(Class<P> clazz,
                      CreateContext ctx,
                      Path path)

Method Detail

load

public void load(com.google.appengine.api.datastore.PropertyContainer node,
                 LoadContext ctx,
                 Path path,
                 P into)

Description copied from interface: Populator

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

There is one special value for loading: If a Result is returned from a translator, 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 Populator<P>

Parameters:

node - 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

into - is an optional parameter; sometimes we need to create an object at a higher level and pass it down through a stack of translators. Most translators will ignore this, but some will have special behavior, for example, this allows collections to be recycled.

save

public void save(P pojo,
                 boolean index,
                 SaveContext ctx,
                 Path path,
                 com.google.appengine.api.datastore.PropertyContainer into)

Description copied from interface: Populator

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

Specified by:

save in interface Populator<P>

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).