com.google.appengine.api.datastore
Class DataTypeTranslator

java.lang.Object
  com.google.appengine.api.datastore.DataTypeTranslator

public final class DataTypeTranslator
extends java.lang.Object

DataTypeTranslator is a utility class for converting between the data store's Property protocol buffers and the the user-facing classes (String, User, etc.).

Nested Class Summary

static class

DataTypeTranslator.ComparableByteArray A wrapper for a byte[] that implements Comparable.

Method Summary

static void	addPropertiesToPb(java.util.Map<java.lang.String,java.lang.Object> map, EntityProto proto) Add all of the properties in the specified map to an EntityProto.
static void	extractImplicitPropertiesFromPb(EntityProto proto, java.util.Map<java.lang.String,java.lang.Object> map) Copy all of the implicit properties present on proto into map.
static void	extractIndexedPropertiesFromPb(EntityProto proto, java.util.Map<java.lang.String,java.lang.Object> map) Copy all of the indexed properties present on proto into map.
static void	extractPropertiesFromPb(EntityProto proto, java.util.Map<java.lang.String,java.lang.Object> map) Copy all of the properties present on proto into map.
static java.util.Collection<Property>	findIndexedPropertiesOnPb(EntityProto proto, java.lang.String propertyName) Locates and returns all indexed properties with the given name on the given proto.
static java.lang.Comparable<java.lang.Object>	getComparablePropertyValue(Property property) Returns the value for the property as its comparable representation type.
static java.lang.Object	getPropertyValue(Property property) Returns the value for the property as its canonical type.
static int	getTypeRank(java.lang.Class<? extends java.lang.Comparable> datastoreType) Get the rank of the given datastore type relative to other datastore types.

Methods inherited from class java.lang.Object

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

Method Detail

addPropertiesToPb

public static void addPropertiesToPb(java.util.Map<java.lang.String,java.lang.Object> map,
                                     EntityProto proto)

Add all of the properties in the specified map to an EntityProto. This involves determining the type of each property and creating the proper type-specific protocol buffer. If the property value is an Entity.UnindexedValue, or if it's a type that is never indexed, e.g. Text and Blob, it's added to EntityProto.raw_property. Otherwise it's added to EntityProto.property.

Parameters:

map - A not null map of all the properties which will be set on proto

proto - A not null protocol buffer

extractIndexedPropertiesFromPb

public static void extractIndexedPropertiesFromPb(EntityProto proto,
                                                  java.util.Map<java.lang.String,java.lang.Object> map)

Copy all of the indexed properties present on proto into map.

extractPropertiesFromPb

public static void extractPropertiesFromPb(EntityProto proto,
                                           java.util.Map<java.lang.String,java.lang.Object> map)

Copy all of the properties present on proto into map.

extractImplicitPropertiesFromPb

public static void extractImplicitPropertiesFromPb(EntityProto proto,
                                                   java.util.Map<java.lang.String,java.lang.Object> map)

Copy all of the implicit properties present on proto into map.

findIndexedPropertiesOnPb

public static java.util.Collection<Property> findIndexedPropertiesOnPb(EntityProto proto,
                                                                       java.lang.String propertyName)

Locates and returns all indexed properties with the given name on the given proto.

getPropertyValue

public static java.lang.Object getPropertyValue(Property property)

Returns the value for the property as its canonical type.

Parameters:

property - a not null property

Returns:

null if no value was set for property

getComparablePropertyValue

public static java.lang.Comparable<java.lang.Object> getComparablePropertyValue(Property property)

Returns the value for the property as its comparable representation type.

Parameters:

property - a not null property

Returns:

null if no value was set for property

getTypeRank

public static int getTypeRank(java.lang.Class<? extends java.lang.Comparable> datastoreType)

Get the rank of the given datastore type relative to other datastore types. Note that datastore types do not necessarily have unique ranks.