Package com.google.datastore.v1.client

Class DatastoreHelper

java.lang.Object

com.google.datastore.v1.client.DatastoreHelper

public final class DatastoreHelper
extends Object

Helper methods for Datastore.

Field Summary

Fields

Modifier and Type	Field	Description
static String	KEY_PROPERTY_NAME	The property used in the Datastore to get the key of the entity.
static String	LOCAL_HOST_ENV_VAR	Name of the environment variable used to set the local host.
static String	PRIVATE_KEY_FILE_ENV_VAR	Name of the environment variable used to set the private key file.
static String	PROJECT_ID_ENV_VAR	Name of the environment variable used to set the project ID.
static String	SCATTER_PROPERTY_NAME	The property used in the Datastore to give us a random distribution.
static String	SERVICE_ACCOUNT_ENV_VAR	Name of the environment variable used to set the service account.

Method Summary

Modifier and Type	Method	Description
static boolean	getBoolean(Value value)
static com.google.protobuf.ByteString	getByteString(Value value)
static Datastore	getDatastoreFromEnv()
static double	getDouble(Value value)
static Entity	getEntity(Value value)
static Key	getKey(Value value)
static Comparator<Key>	getKeyComparator()
static List<Value>	getList(Value value)
static long	getLong(Value value)
static DatastoreOptions.Builder	getOptionsFromEnv()	Constructs a Datastore from environment variables and/or the Compute Engine metadata server.
static String	getProjectIdFromComputeEngine()	Gets the project ID from the Compute Engine metadata server.
static QuerySplitter	getQuerySplitter()	Gets a QuerySplitter.
static com.google.api.client.auth.oauth2.Credential	getServiceAccountCredential(String serviceAccountId, String privateKeyFile)	Constructs credentials for the given account and key.
static com.google.api.client.auth.oauth2.Credential	getServiceAccountCredential(String serviceAccountId, String privateKeyFile, Collection<String> serviceAccountScopes)	Constructs credentials for the given account and key file.
static com.google.api.client.auth.oauth2.Credential	getServiceAccountCredential(String serviceAccountId, PrivateKey privateKey, Collection<String> serviceAccountScopes)	Constructs credentials for the given account and key.
static String	getString(Value value)
static long	getTimestamp(Value value)
static Filter.Builder	makeAncestorFilter(Key ancestor)	Makes an ancestor filter.
static Filter.Builder	makeAndFilter(Filter... subfilters)	Make a composite filter from the given sub-filters using AND to combine filters.
static Filter.Builder	makeAndFilter(Iterable<Filter> subfilters)	Make a composite filter from the given sub-filters using AND to combine filters.
static Mutation.Builder	makeDelete(Key key)
static Filter.Builder	makeFilter(String property, PropertyFilter.Operator operator, Value value)	Make a filter on a property for use in a query.
static Filter.Builder	makeFilter(String property, PropertyFilter.Operator operator, Value.Builder value)	Make a filter on a property for use in a query.
static Mutation.Builder	makeInsert(Entity entity)
static Key.Builder	makeKey(Object... elements)	Make a key from the specified path of kind/id-or-name pairs and/or Keys.
static PropertyOrder.Builder	makeOrder(String property, PropertyOrder.Direction direction)	Make a sort order for use in a query.
static PropertyReference.Builder	makePropertyReference(String propertyName)	Make a property reference for use in a query.
static Mutation.Builder	makeUpdate(Entity entity)
static Mutation.Builder	makeUpsert(Entity entity)
static Value.Builder	makeValue(boolean value)	Make a boolean value.
static Value.Builder	makeValue(double value)	Make a floating point value.
static Value.Builder	makeValue(long key)	Make an integer value.
static Value.Builder	makeValue(Entity entity)	Make an entity value.
static Value.Builder	makeValue(Entity.Builder entity)	Make a entity value.
static Value.Builder	makeValue(Key key)	Make a key value.
static Value.Builder	makeValue(Key.Builder key)	Make a key value.
static Value.Builder	makeValue(Value.Builder value1, Value.Builder value2, Value.Builder... rest)	Make an array value containing the specified values.
static Value.Builder	makeValue(Value value1, Value value2, Value... rest)	Make a list value containing the specified values.
static Value.Builder	makeValue(com.google.protobuf.ByteString blob)	Make a ByteString value.
static Value.Builder	makeValue(com.google.type.LatLng value)	Makes a GeoPoint value.
static Value.Builder	makeValue(com.google.type.LatLng.Builder value)	Makes a GeoPoint value.
static Value.Builder	makeValue(Iterable<Value> values)	Make an array value containing the specified values.
static Value.Builder	makeValue(String value)	Make a string value.
static Value.Builder	makeValue(Date date)	Make a timestamp value given a date.
static Date	toDate(Value value)	Convert a timestamp value into a Date clipping off the microseconds.

Methods inherited from class java.lang.Object

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

Field Detail

SCATTER_PROPERTY_NAME

public static final String SCATTER_PROPERTY_NAME

The property used in the Datastore to give us a random distribution. *

See Also:

Constant Field Values

KEY_PROPERTY_NAME

public static final String KEY_PROPERTY_NAME

The property used in the Datastore to get the key of the entity. *

See Also:

Constant Field Values

PROJECT_ID_ENV_VAR

public static final String PROJECT_ID_ENV_VAR

Name of the environment variable used to set the project ID.

See Also:

Constant Field Values

LOCAL_HOST_ENV_VAR

public static final String LOCAL_HOST_ENV_VAR

Name of the environment variable used to set the local host.

See Also:

Constant Field Values

SERVICE_ACCOUNT_ENV_VAR

public static final String SERVICE_ACCOUNT_ENV_VAR

Name of the environment variable used to set the service account.

See Also:

Constant Field Values

PRIVATE_KEY_FILE_ENV_VAR

public static final String PRIVATE_KEY_FILE_ENV_VAR

Name of the environment variable used to set the private key file.

See Also:

Constant Field Values

Method Detail

getServiceAccountCredential

public static com.google.api.client.auth.oauth2.Credential getServiceAccountCredential(String serviceAccountId,
                                                                                       String privateKeyFile)
                                                                                throws GeneralSecurityException,
                                                                                       IOException

Constructs credentials for the given account and key.

Parameters:

serviceAccountId - service account ID (typically an e-mail address).

privateKeyFile - the file name from which to get the private key.

Returns:

valid credentials or null

Throws:

GeneralSecurityException

IOException

getServiceAccountCredential

public static com.google.api.client.auth.oauth2.Credential getServiceAccountCredential(String serviceAccountId,
                                                                                       String privateKeyFile,
                                                                                       Collection<String> serviceAccountScopes)
                                                                                throws GeneralSecurityException,
                                                                                       IOException

Constructs credentials for the given account and key file.

Parameters:

serviceAccountId - service account ID (typically an e-mail address).

privateKeyFile - the file name from which to get the private key.

serviceAccountScopes - Collection of OAuth scopes to use with the the service account flow or null if not.

Returns:

valid credentials or null

Throws:

GeneralSecurityException

IOException

getServiceAccountCredential

public static com.google.api.client.auth.oauth2.Credential getServiceAccountCredential(String serviceAccountId,
                                                                                       PrivateKey privateKey,
                                                                                       Collection<String> serviceAccountScopes)
                                                                                throws GeneralSecurityException,
                                                                                       IOException

Constructs credentials for the given account and key.

Parameters:

serviceAccountId - service account ID (typically an e-mail address).

privateKey - the private key for the given account.

serviceAccountScopes - Collection of OAuth scopes to use with the the service account flow or null if not.

Returns:

valid credentials or null

Throws:

GeneralSecurityException

IOException

getOptionsFromEnv

public static DatastoreOptions.Builder getOptionsFromEnv()
                                                  throws GeneralSecurityException,
                                                         IOException

Constructs a Datastore from environment variables and/or the Compute Engine metadata server.

The project ID is determined from, in order of preference:

• DATASTORE_PROJECT_ID environment variable
• Compute Engine

Credentials are taken from, in order of preference:

1. No credentials (if the DATASTORE_EMULATOR_HOST environment variable is set)
2. Service Account specified by the DATASTORE_SERVICE_ACCOUNT and DATASTORE_PRIVATE_KEY_FILE environment variables
3. Google Application Default as described here.

Throws:

GeneralSecurityException

IOException

getProjectIdFromComputeEngine

@Nullable
public static String getProjectIdFromComputeEngine()

Gets the project ID from the Compute Engine metadata server. Returns null if the project ID cannot be determined (because, for instance, the code is not running on Compute Engine).

getDatastoreFromEnv

public static Datastore getDatastoreFromEnv()
                                     throws GeneralSecurityException,
                                            IOException

Throws:

GeneralSecurityException

IOException

See Also:

getOptionsFromEnv()

getQuerySplitter

public static QuerySplitter getQuerySplitter()

Gets a QuerySplitter.

The returned QuerySplitter.getSplits(com.google.datastore.v1.Query, com.google.datastore.v1.PartitionId, int, com.google.datastore.v1.client.Datastore) cannot accept a query that contains inequality filters, a sort filter, or a missing kind.

getKeyComparator

public static Comparator<Key> getKeyComparator()

makeOrder

public static PropertyOrder.Builder makeOrder(String property,
                                              PropertyOrder.Direction direction)

Make a sort order for use in a query.

makeAncestorFilter

public static Filter.Builder makeAncestorFilter(Key ancestor)

Makes an ancestor filter.

makeFilter

public static Filter.Builder makeFilter(String property,
                                        PropertyFilter.Operator operator,
                                        Value value)

Make a filter on a property for use in a query.

makeFilter

public static Filter.Builder makeFilter(String property,
                                        PropertyFilter.Operator operator,
                                        Value.Builder value)

Make a filter on a property for use in a query.

makeAndFilter

public static Filter.Builder makeAndFilter(Filter... subfilters)

Make a composite filter from the given sub-filters using AND to combine filters.

makeAndFilter

public static Filter.Builder makeAndFilter(Iterable<Filter> subfilters)

Make a composite filter from the given sub-filters using AND to combine filters.

makePropertyReference

public static PropertyReference.Builder makePropertyReference(String propertyName)

Make a property reference for use in a query.

makeValue

public static Value.Builder makeValue(Iterable<Value> values)

Make an array value containing the specified values.

makeValue

public static Value.Builder makeValue(Value value1,
                                      Value value2,
                                      Value... rest)

Make a list value containing the specified values.

makeValue

public static Value.Builder makeValue(Value.Builder value1,
                                      Value.Builder value2,
                                      Value.Builder... rest)

Make an array value containing the specified values.

makeValue

public static Value.Builder makeValue(Key key)

Make a key value.

makeValue

public static Value.Builder makeValue(Key.Builder key)

Make a key value.

makeValue

public static Value.Builder makeValue(long key)

Make an integer value.

makeValue

public static Value.Builder makeValue(double value)

Make a floating point value.

makeValue

public static Value.Builder makeValue(boolean value)

Make a boolean value.

makeValue

public static Value.Builder makeValue(String value)

Make a string value.

makeValue

public static Value.Builder makeValue(Entity entity)

Make an entity value.

makeValue

public static Value.Builder makeValue(Entity.Builder entity)

Make a entity value.

makeValue

public static Value.Builder makeValue(com.google.protobuf.ByteString blob)

Make a ByteString value.

makeValue

public static Value.Builder makeValue(Date date)

Make a timestamp value given a date.

makeValue

public static Value.Builder makeValue(com.google.type.LatLng value)

Makes a GeoPoint value.

makeValue

public static Value.Builder makeValue(com.google.type.LatLng.Builder value)

Makes a GeoPoint value.

makeKey

public static Key.Builder makeKey(Object... elements)

Make a key from the specified path of kind/id-or-name pairs and/or Keys.

The id-or-name values must be either String, Long, Integer or Short.

The last id-or-name value may be omitted, in which case an entity without an id is created (for use with automatic id allocation).

The PartitionIds of all Keys in the path must be equal. The returned Key.Builder will use this PartitionId.

getDouble

public static double getDouble(Value value)

Returns:

the double contained in value

Throws:

IllegalArgumentException - if the value does not contain a double.

getKey

public static Key getKey(Value value)

Returns:

the key contained in value

Throws:

IllegalArgumentException - if the value does not contain a key.

getByteString

public static com.google.protobuf.ByteString getByteString(Value value)

Returns:

the blob contained in value

Throws:

IllegalArgumentException - if the value does not contain a blob.

getEntity

public static Entity getEntity(Value value)

Returns:

the entity contained in value

Throws:

IllegalArgumentException - if the value does not contain an entity.

getString

public static String getString(Value value)

Returns:

the string contained in value

Throws:

IllegalArgumentException - if the value does not contain a string.

getBoolean

public static boolean getBoolean(Value value)

Returns:

the boolean contained in value

Throws:

IllegalArgumentException - if the value does not contain a boolean.

getLong

public static long getLong(Value value)

Returns:

the long contained in value

Throws:

IllegalArgumentException - if the value does not contain a long.

getTimestamp

public static long getTimestamp(Value value)

Returns:

the timestamp in microseconds contained in value

Throws:

IllegalArgumentException - if the value does not contain a timestamp.

getList

public static List<Value> getList(Value value)

Returns:

the array contained in value as a list.

Throws:

IllegalArgumentException - if the value does not contain an array.

toDate

public static Date toDate(Value value)

Convert a timestamp value into a Date clipping off the microseconds.

Parameters:

value - a timestamp value to convert

Returns:

the resulting Date

Throws:

IllegalArgumentException - if the value does not contain a timestamp.

makeInsert

public static Mutation.Builder makeInsert(Entity entity)

Parameters:

entity - the entity to insert

Returns:

a mutation that will insert an entity

makeUpdate

public static Mutation.Builder makeUpdate(Entity entity)

Parameters:

entity - the entity to update

Returns:

a mutation that will update an entity

makeUpsert

public static Mutation.Builder makeUpsert(Entity entity)

Parameters:

entity - the entity to upsert

Returns:

a mutation that will upsert an entity

makeDelete

public static Mutation.Builder makeDelete(Key key)

Parameters:

key - the key of the entity to delete

Returns:

a mutation that will delete an entity