org.springframework.cloud.gcp.data.datastore.core

Interface DatastoreOperations

All Known Implementing Classes:

DatastoreTemplate

public interface DatastoreOperations

An interface of operations that can be done with Cloud Datastore.

Since:

1.1

Author:

Chengyuan Zhao

Method Summary

Modifier and Type	Method and Description
long	count(Class<?> entityClass) Count all occurrences of entities of the given domain type.
com.google.cloud.datastore.Key	createKey(String kind, Object id) Create a Key from kind name and id.
<T> void	delete(T entity) Delete an entity from Cloud Datastore.
long	deleteAll(Class<?> entityClass) Delete all entities of a given domain type.
<T> void	deleteAll(Iterable<T> entities) Deletes multiple entities from Cloud Datastore.
<T> void	deleteAllById(Iterable<?> ids, Class<T> entityClass) Delete multiple IDs from Cloud Datastore.
<T> void	deleteById(Object id, Class<T> entityClass) Delete an entity from Cloud Datastore.
<T> boolean	existsById(Object id, Class<T> entityClass) Check if the given ID belongs to an entity in Cloud Datastore.
<T> Iterable<T>	findAll(Class<T> entityClass) Get all the entities of the given domain type.
<T> Collection<T>	findAll(Class<T> entityClass, DatastoreQueryOptions queryOptions) Get all the entities of the given domain type applying limit, offset and sort.
<T> Iterable<T>	findAllById(Iterable<?> ids, Class<T> entityClass) Find all the entities of the given IDs.
<T> T	findById(Object id, Class<T> entityClass) Get an entity based on a id.
<T> Map<String,T>	findByIdAsMap(com.google.cloud.datastore.Key key, Class<T> valueType) Get a Datastore entity based on a id and convert it to a map.
<A> A	performTransaction(Function<DatastoreOperations,A> operations) Performs multiple read and write operations in a single transaction.
<T> Iterable<T>	query(com.google.cloud.datastore.Query<? extends com.google.cloud.datastore.BaseEntity> query, Class<T> entityClass) Finds objects by using a Cloud Datastore query.
<A,T> Iterable<T>	query(com.google.cloud.datastore.Query<A> query, Function<A,T> entityFunc) Runs given query and applies given function to each entity in the result.
Iterable<com.google.cloud.datastore.Key>	queryKeys(com.google.cloud.datastore.Query<com.google.cloud.datastore.Key> query) Finds Cloud Datastore Keys by using a Cloud Datastore query.
<T> T	save(T instance, com.google.cloud.datastore.Key... ancestors) Saves an instance of an object to Cloud Datastore.
<T> Iterable<T>	saveAll(Iterable<T> entities, com.google.cloud.datastore.Key... ancestors) Saves multiple instances of objects to Cloud Datastore.
<V> void	writeMap(com.google.cloud.datastore.Key key, Map<String,V> map) Save a map as a Datastore entity, using map keys as field names.

Method Detail

findById

<T> T findById(Object id,
               Class<T> entityClass)

Get an entity based on a id.

Type Parameters:

T - the class type of the entity.

Parameters:

id - the id of the entity. If this is actually a Key then it will be used. Otherwise it will be attempted to be converted to an integer or string value and it will be assumed to be a root key value with the Kind determined by the entityClass. param.

entityClass - the type of the entity to get.

Returns:

the entity that was found with that id.

save

<T> T save(T instance,
           com.google.cloud.datastore.Key... ancestors)

Saves an instance of an object to Cloud Datastore. Behaves as update or insert. Ancestors can be added only to entries with Key ids.

Type Parameters:

T - the type of the object to save

Parameters:

instance - the instance to save.

ancestors - ancestors that should be added to the entry

Returns:

the instance that was saved.

saveAll

<T> Iterable<T> saveAll(Iterable<T> entities,
                        com.google.cloud.datastore.Key... ancestors)

Saves multiple instances of objects to Cloud Datastore. Behaves as update or insert. Ancestors can be added only to entries with Key ids.

Type Parameters:

T - the type of entities to save

Parameters:

entities - the objects to save.

ancestors - ancestors that should be added to each entry

Returns:

the entities that were saved.

deleteById

<T> void deleteById(Object id,
                    Class<T> entityClass)

Delete an entity from Cloud Datastore. Deleting IDs that do not exist in Cloud Datastore will result in no operation.

Type Parameters:

T - ths entity type

Parameters:

id - the ID of the entity to delete. If this is actually a Key then it will be used. Otherwise it will be attempted to be converted to an integer or string value and it will be assumed to be a root key value with the Kind determined by the entityClass.

entityClass - the type of the

deleteAllById

<T> void deleteAllById(Iterable<?> ids,
                       Class<T> entityClass)

Delete multiple IDs from Cloud Datastore. Deleting IDs that do not exist in Cloud Datastore will result in no operation.

Type Parameters:

T - ths entity type

Parameters:

ids - the IDs to delete. If any of these is actually a Key then it will be used. Otherwise it will be attempted to be converted to an integer or string value and it will be assumed to be a root key value with the Kind determined by the entityClass.

entityClass - the type of the

delete

<T> void delete(T entity)

Delete an entity from Cloud Datastore. Deleting entities that don't exist in Cloud Datastore will result in no operation.

Type Parameters:

T - the entity type

Parameters:

entity - the entity to delete.

deleteAll

<T> void deleteAll(Iterable<T> entities)

Deletes multiple entities from Cloud Datastore. Deleting entities that don't exist in Cloud Datastore will result in no operation.

Type Parameters:

T - the entity type.

Parameters:

entities - the entities to delete.

deleteAll

long deleteAll(Class<?> entityClass)

Delete all entities of a given domain type.

Parameters:

entityClass - the domain type to delete from Cloud Datastore.

Returns:

the number of entities that were deleted.

count

long count(Class<?> entityClass)

Count all occurrences of entities of the given domain type.

Parameters:

entityClass - the domain type to count.

Returns:

the number of entities of the given type.

findAllById

<T> Iterable<T> findAllById(Iterable<?> ids,
                            Class<T> entityClass)

Find all the entities of the given IDs. If an ID is actually a Key then it will be used. Otherwise it will be attempted to be converted to an integer or string value and it will be assumed to be a root key value with the Kind determined by the entityClass.

Type Parameters:

T - the type parameter of the domain type.

Parameters:

ids - the IDs to search.

entityClass - the domain type of the objects.

Returns:

the entities that were found.

query

<T> Iterable<T> query(com.google.cloud.datastore.Query<? extends com.google.cloud.datastore.BaseEntity> query,
                      Class<T> entityClass)

Finds objects by using a Cloud Datastore query.

Type Parameters:

T - the type of object to retrieve.

Parameters:

query - the query to execute.

entityClass - the type of object to retrieve.

Returns:

a list of the objects found. If no keys could be found the list will be empty.

query

<A,T> Iterable<T> query(com.google.cloud.datastore.Query<A> query,
                        Function<A,T> entityFunc)

Runs given query and applies given function to each entity in the result.

Type Parameters:

A - the row type of the query. This type can be either Key or a Cloud Datastore entity.

T - the type to map each entity or key to.

Parameters:

query - the query to run.

entityFunc - the function to apply to each found entity or key.

Returns:

the mapped entities or keys.

queryKeys

Iterable<com.google.cloud.datastore.Key> queryKeys(com.google.cloud.datastore.Query<com.google.cloud.datastore.Key> query)

Finds Cloud Datastore Keys by using a Cloud Datastore query.

Parameters:

query - the query to execute that retrieves only Keys.

Returns:

the list of keys found.

findAll

<T> Iterable<T> findAll(Class<T> entityClass)

Get all the entities of the given domain type.

Type Parameters:

T - the type param of the domain type.

Parameters:

entityClass - the domain type to get.

Returns:

the entities that were found.

findAll

<T> Collection<T> findAll(Class<T> entityClass,
                          DatastoreQueryOptions queryOptions)

Get all the entities of the given domain type applying limit, offset and sort.

Type Parameters:

T - the type param of the domain type.

Parameters:

entityClass - the domain type to get.

queryOptions - query options

Returns:

the entities that were found.

existsById

<T> boolean existsById(Object id,
                       Class<T> entityClass)

Check if the given ID belongs to an entity in Cloud Datastore. If this is actually a Key then it will be used. Otherwise it will be attempted to be converted to an integer or string value and it will be assumed to be a root key value with the Kind determined by the entityClass.

Type Parameters:

T - the type param of the domain type.

Parameters:

id - the ID to search for.

entityClass - the domain type of the entities to search for.

Returns:

true if the given ID refers to an existing entity. False otherwise.

performTransaction

<A> A performTransaction(Function<DatastoreOperations,A> operations)

Performs multiple read and write operations in a single transaction.

Type Parameters:

A - the final return type of the operations.

Parameters:

operations - the function that uses DatastoreOperations to perform operations in a transaction.

Returns:

the final result of the transaction.

findByIdAsMap

<T> Map<String,T> findByIdAsMap(com.google.cloud.datastore.Key key,
                                Class<T> valueType)

Get a Datastore entity based on a id and convert it to a map.

Type Parameters:

T - the value type of the map

Parameters:

key - the key of the entity

valueType - type values should be converted to

Returns:

if an entity for a given key exists, returns the map representation of it, null otherwise

writeMap

<V> void writeMap(com.google.cloud.datastore.Key key,
                  Map<String,V> map)

Save a map as a Datastore entity, using map keys as field names.

Type Parameters:

V - the value type of the map to write

Parameters:

key - the key for the entity

map - a map

createKey

com.google.cloud.datastore.Key createKey(String kind,
                                         Object id)

Create a Key from kind name and id.

Parameters:

kind - the Cloud Datastore kind name

id - object to be used as id; if it is a Long, the value is used, otherwise it is converted to String

Returns:

created key