com.microsoft.azure.storage.table

Interface TableEntity

All Known Implementing Classes:

DynamicTableEntity, TableServiceEntity

public interface TableEntity

An interface required for table entity types. The TableEntity interface declares getter and setter methods for the common entity properties, and writeEntity and readEntity methods for serialization and deserialization of all entity properties using a property map. Create classes implementing TableEntity to customize property storage, retrieval, serialization and deserialization, and to provide additional custom logic for a table entity.

The Storage client library includes two implementations of TableEntity that provide for simple property access and serialization:

DynamicTableEntity implements TableEntity and provides a simple property map to store and retrieve properties. Use a DynamicTableEntity for simple access to entity properties when only a subset of properties are returned (for example, by a select clause in a query), or for when your query can return multiple entity types with different properties. You can also use this type to perform bulk table updates of heterogeneous entities without losing property information.

TableServiceEntity is an implementation of TableEntity that uses reflection-based serialization and deserialization behavior in its writeEntity and readEntity methods. TableServiceEntity-derived classes with methods that follow a convention for types and naming are serialized and deserialized automatically.

Any class that implements TableEntity can take advantage of the automatic reflection-based serialization and deserialization behavior in TableServiceEntity by invoking the static methods TableServiceEntity.readEntityWithReflection in readEntity and TableServiceEntity.writeEntityWithReflection in writeEntity. The class must provide methods that follow the type and naming convention to be serialized and deserialized automatically. When both a getter method and setter method are found for a given property name and data type, then the appropriate method is invoked automatically to serialize or deserialize the data. The reflection code looks for getter and setter methods in pairs of the form

public type getPropertyName() { ... }

and

public void setPropertyName(type parameter) { ... }

where PropertyName is a property name for the table entity, and type is compatible with the EDM data type of the property. See the table in the class description for TableServiceEntity for a map of property types to their language equivalents. The StoreAs annotation may be applied with a name attribute to specify a property name for reflection on getter and setter methods that do not follow the property name convention. Method names and the name attribute of StoreAs annotations are case sensitive for matching property names with reflection. Use the Ignore annotation to prevent methods from being used by reflection for automatic serialization and deserialization. Note that the names "PartitionKey", "RowKey", "Timestamp", and "Etag" are reserved and will be ignored if set with the StoreAs annotation in a subclass that uses the reflection methods.

See Also:

TableServiceEntity, DynamicTableEntity

Method Summary

Methods

Modifier and Type	Method and Description
String	getEtag() Gets the ETag value to verify for the entity.
String	getPartitionKey() Gets the PartitionKey value for the entity.
String	getRowKey() Gets the RowKey value for the entity.
Date	getTimestamp() Gets the Timestamp for the entity.
void	readEntity(HashMap<String,EntityProperty> properties, OperationContext opContext) Populates an instance of the object implementing TableEntity using the specified properties parameter, which represents a map of String property names to EntityProperty data typed values.
void	setEtag(String etag) Sets the ETag value to verify for the entity.
void	setPartitionKey(String partitionKey) Sets the PartitionKey value for the entity.
void	setRowKey(String rowKey) Sets the RowKey value for the entity.
void	setTimestamp(Date timeStamp) Sets the Timestamp value for the entity.
HashMap<String,EntityProperty>	writeEntity(OperationContext opContext) Returns a map of String property names to EntityProperty data typed values that represents the serialized content of the table entity instance.

Method Detail

getEtag

String getEtag()

Gets the ETag value to verify for the entity. This value is used to determine if the table entity has changed since it was last read from Microsoft Azure storage. The client cannot update this value on the service.

Returns:

A String which represents the ETag for the entity.

getPartitionKey

String getPartitionKey()

Gets the PartitionKey value for the entity.

Returns:

A String which represents the PartitionKey value for the entity.

getRowKey

String getRowKey()

Gets the RowKey value for the entity.

Returns:

A String which represents the RowKey value for the entity.

getTimestamp

Date getTimestamp()

Gets the Timestamp for the entity. The server manages the value of Timestamp, which cannot be modified.

Returns:

A java.util.Date object which represents the Timestamp value for the entity.

readEntity

void readEntity(HashMap<String,EntityProperty> properties,
              OperationContext opContext)
                throws StorageException

Populates an instance of the object implementing TableEntity using the specified properties parameter, which represents a map of String property names to EntityProperty data typed values.

Parameters:

properties - The java.util.HashMap of String to EntityProperty data typed values to use to populate the table entity instance.

opContext - An OperationContext object used to track the execution of the operation.

Throws:

StorageException - If an error occurs during the operation.

setEtag

void setEtag(String etag)

Sets the ETag value to verify for the entity. This value is used to determine if the table entity has changed since it was last read from Microsoft Azure storage. The client cannot update this value on the service.

Parameters:

etag - A String which specifies the ETag to set for the entity.

setPartitionKey

void setPartitionKey(String partitionKey)

Sets the PartitionKey value for the entity.

Parameters:

partitionKey - A String which specifies the PartitionKey value to set for the entity.

setRowKey

void setRowKey(String rowKey)

Sets the RowKey value for the entity.

Parameters:

rowKey - A String which specifies the RowKey value to set for the entity.

setTimestamp

void setTimestamp(Date timeStamp)

Sets the Timestamp value for the entity. Note that timestamp is a read-only property on the service and should not be set by the user.

Parameters:

timeStamp - A java.util.Date which specifies the Timestamp value to set for the entity.

writeEntity

HashMap<String,EntityProperty> writeEntity(OperationContext opContext)
                                           throws StorageException

Returns a map of String property names to EntityProperty data typed values that represents the serialized content of the table entity instance.

Parameters:

opContext - An OperationContext object used to track the execution of the operation.

Returns:

A java.util.HashMap of String property names to EntityProperty data typed values representing the properties of the table entity.

Throws:

StorageException - If an error occurs during the operation.