com.microsoft.windowsazure.storage.table.TableEntity Maven / Gradle / Ivy
/**
* Copyright Microsoft Corporation
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package com.microsoft.windowsazure.storage.table;
import java.util.Date;
import java.util.HashMap;
import com.microsoft.windowsazure.storage.OperationContext;
import com.microsoft.windowsazure.storage.StorageException;
/**
* An interface required for table entity types. The {@link 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 {@link 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 {@link TableEntity} that provide for simple property
* access and serialization:
*
* {@link DynamicTableEntity} implements {@link TableEntity} and provides a simple property map to store and retrieve
* properties. Use a {@link 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.
*
* {@link TableServiceEntity} is an implementation of {@link TableEntity} that uses reflection-based serialization and
* deserialization behavior in its writeEntity and readEntity methods.
* {@link TableServiceEntity}-derived classes with methods that follow a convention for types and naming are serialized
* and deserialized automatically.
*
* Any class that implements {@link TableEntity} can take advantage of the automatic reflection-based serialization and
* deserialization behavior in {@link 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 a Java type compatible with
* the EDM data type of the property. See the table in the class description for {@link TableServiceEntity} for a map of
* property types to their Java equivalents. The {@link 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 {@link StoreAs} annotations are case sensitive for
* matching property names with reflection. Use the {@link 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 {@link StoreAs} annotation in a subclass
* that uses the reflection methods.
*
*
* @see TableServiceEntity
* @see DynamicTableEntity
*/
public interface TableEntity {
/**
* Gets the Etag value for the entity. This value is used to determine if the table entity has changed since it was
* last read from Windows Azure storage.
*
* @return
* A String containing the Etag for the entity.
*/
public String getEtag();
/**
* Gets the PartitionKey value for the entity.
*
* @return
* A String containing the PartitionKey value for the entity.
*/
public String getPartitionKey();
/**
* Gets the RowKey value for the entity.
*
* @return
* A String containing the RowKey value for the entity.
*/
public String getRowKey();
/**
* Gets the Timestamp for the entity.
*
* @return
* A Date containing the Timestamp value for the entity.
*/
public Date getTimestamp();
/**
* Populates an instance of the object implementing {@link TableEntity} using the specified properties parameter,
* containing a map of String property names to {@link EntityProperty} data typed values.
*
* @param properties
* The java.util.HashMap of String to {@link EntityProperty} data typed values
* to use to populate the table entity instance.
* @param opContext
* An {@link OperationContext} object used to track the execution of the operation.
* @throws StorageException
* if an error occurs during the operation.
*/
public void readEntity(HashMap properties, OperationContext opContext)
throws StorageException;
/**
* Sets the Etag for the entity.
*
* @param etag
* The String containing the Etag to set for the entity.
*/
public void setEtag(String etag);
/**
* Sets the PartitionKey value for the entity.
*
* @param partitionKey
* The String containing the PartitionKey value to set for the entity.
*/
public void setPartitionKey(String partitionKey);
/**
* Sets the RowKey value for the entity.
*
* @param rowKey
* The String containing the RowKey value to set for the entity.
*/
public void setRowKey(String rowKey);
/**
* Sets the Timestamp value for the entity.
*
* @param timeStamp
* The Date containing the Timestamp value to set for the entity.
*/
public void setTimestamp(Date timeStamp);
/**
* Returns a map of String property names to {@link EntityProperty} data typed values
* that represents the serialized content of the table entity instance.
*
* @param opContext
* An {@link OperationContext} object used to track the execution of the operation.
* @return
* The java.util.HashMap of String property names to {@link EntityProperty} data
* typed values representing the properties of the table entity.
*
* @throws StorageException
* if an error occurs during the operation.
*/
public HashMap writeEntity(OperationContext opContext) throws StorageException;
}