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DataTypeTranslator (Google App Engine API for Java)

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 user-facing classes (String, User, etc.).

Nested Class Summary

Nested Classes
Modifier and Type Class and Description

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

Method Summary

All Methods Static Methods Concrete Methods
Modifier and Type	Method and Description
`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.
`static Entity`	`toEntityFromSerializedV1Proto(byte[] serializedV1Entity)` Deserializes a Cloud Datastore V1 `Entity` protobuf and converts it to an App Engine Datastore `Entity`.
`static byte[]`	`toSerializedV1Proto(Entity entity)` Converts an App Engine Datastore `Entity` to a Cloud Datastore `Entity` V1 protobuf and serializes it.

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. If there are a mix of matching multiple and non-multiple properties, the collection will contain the first non-multiple property.
    
    Returns:
    
    A list, potentially empty, containing matching properties.
  - 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
  - toEntityFromSerializedV1Proto
```
public static Entity toEntityFromSerializedV1Proto(byte[] serializedV1Entity)
```
    Deserializes a Cloud Datastore V1 Entity protobuf and converts it to an App Engine Datastore Entity. serializedV1Entity should be an output of toSerializedV1Proto(com.google.appengine.api.datastore.Entity); no guarantees for other inputs.
    
    Throws:
    
    java.lang.IllegalArgumentException - if the argument could not be deserialized
  - toSerializedV1Proto
```
public static byte[] toSerializedV1Proto(Entity entity)
```
    Converts an App Engine Datastore Entity to a Cloud Datastore Entity V1 protobuf and serializes it.
    Note that the conversion may be lossy or fail; for example, the Cloud Datastore V1 API supports only UTF-8 strings, so App Engine Datastore entities with string properties that are not UTF-8 encoded may behave in unexpected ways if supplied to Cloud Datastore. You can verify that the conversion was successful for entity x by checking x.equals(toEntityFromSerializedV1Proto(toSerializedV1Proto(x)).
  - 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.

Except as otherwise noted, the content of this page is licensed under the Creative Commons Attribution 4.0 License, and code samples are licensed under the Apache 2.0 License. For details, see the Google Developers Site Policies. Java is a registered trademark of Oracle and/or its affiliates.

Last updated 2025-06-16 UTC.

DataTypeTranslator (Google App Engine API for Java) Stay organized with collections Save and categorize content based on your preferences.

Class DataTypeTranslator

Nested Class Summary

Method Summary

Methods inherited from class java.lang.Object

Method Detail

addPropertiesToPb

extractIndexedPropertiesFromPb

extractPropertiesFromPb

extractImplicitPropertiesFromPb

findIndexedPropertiesOnPb

getPropertyValue

toEntityFromSerializedV1Proto

toSerializedV1Proto

getComparablePropertyValue

getTypeRank

DataTypeTranslator (Google App Engine API for Java)