com.googlecode.objectify.impl

Class LoadEngine

java.lang.Object

com.googlecode.objectify.impl.LoadEngine

public class LoadEngine
extends Object

Represents one "batch" of loading. Get a number of Result objects, then execute(). Some work is done right away, some work is done on the first get(). There might be multiple rounds of execution to process all the @Load groups, but that is invisible outside this class.

Author:

Jeff Schnitzer

Constructor Summary

Constructors

Constructor and Description
LoadEngine(ObjectifyImpl<?> ofy, Session session, com.google.appengine.api.datastore.AsyncDatastoreService ads, LoadArrangement loadArrangement)

Method Summary

Modifier and Type	Method and Description
void	execute() Starts asychronous fetching of the batch.
Result<Map<com.google.appengine.api.datastore.Key,com.google.appengine.api.datastore.Entity>>	fetch(Set<com.google.appengine.api.datastore.Key> keys) Fetch the keys from the async datastore using the current transaction context
LoadArrangement	getLoadArrangement()
Session	getSession()
<T> T	load(com.google.appengine.api.datastore.Entity ent, LoadContext ctx) Converts a datastore entity into a typed pojo object
<T> Result<T>	load(Key<T> key) Gets the result, possibly from the session, putting it in the session if necessary.
<T> Ref<T>	makeRef(Key<?> rootEntity, LoadConditions loadConditions, Key<T> key) Create a Ref for the key, and maybe start a load operation depending on current load groups.
boolean	shouldLoad(LoadConditions loadConditions)
void	stuff(com.google.appengine.api.datastore.Entity ent) Stuffs an Entity into a place where values in the round can be obtained instead of going to the datastore.
Result<Map<Key<?>,Object>>	translate(Result<Map<com.google.appengine.api.datastore.Key,com.google.appengine.api.datastore.Entity>> raw) Asynchronously translate raw to processed; might produce successive load operations as refs are filled in

Methods inherited from class java.lang.Object

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

Constructor Detail

LoadEngine

public LoadEngine(ObjectifyImpl<?> ofy,
                  Session session,
                  com.google.appengine.api.datastore.AsyncDatastoreService ads,
                  LoadArrangement loadArrangement)

Method Detail

load

public <T> Result<T> load(Key<T> key)

Gets the result, possibly from the session, putting it in the session if necessary. Also will recursively prepare the session with @Load parents as appropriate.

Throws:

NullPointerException - if key is null

execute

public void execute()

Starts asychronous fetching of the batch.

makeRef

public <T> Ref<T> makeRef(Key<?> rootEntity,
                          LoadConditions loadConditions,
                          Key<T> key)

Create a Ref for the key, and maybe start a load operation depending on current load groups.

Parameters:

rootEntity - is the entity key which holds this property (possibly through some level of embedded objects)

shouldLoad

public boolean shouldLoad(LoadConditions loadConditions)

Returns:

true if the specified property should be loaded in this batch

stuff

public void stuff(com.google.appengine.api.datastore.Entity ent)

Stuffs an Entity into a place where values in the round can be obtained instead of going to the datastore. Called by non-hybrid queries to add results and eliminate batch fetching.

translate

public Result<Map<Key<?>,Object>> translate(Result<Map<com.google.appengine.api.datastore.Key,com.google.appengine.api.datastore.Entity>> raw)

Asynchronously translate raw to processed; might produce successive load operations as refs are filled in

fetch

public Result<Map<com.google.appengine.api.datastore.Key,com.google.appengine.api.datastore.Entity>> fetch(Set<com.google.appengine.api.datastore.Key> keys)

Fetch the keys from the async datastore using the current transaction context

load

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

Converts a datastore entity into a typed pojo object

Returns:

an assembled pojo, or the Entity itself if the kind is not registered, or null if the input value was null

getSession

public Session getSession()

getLoadArrangement

public LoadArrangement getLoadArrangement()