com.gigaspaces.datasource.concurrentaccess

Class SharedIteratorSpaceDataSourceDecorator

java.lang.Object

com.gigaspaces.datasource.SpaceDataSource

com.gigaspaces.datasource.concurrentaccess.SharedIteratorSpaceDataSourceDecorator

All Implemented Interfaces:

ISharedDataIteratorSourceStateChangedListener<Object>

public class SharedIteratorSpaceDataSourceDecorator
extends SpaceDataSource
implements ISharedDataIteratorSourceStateChangedListener<Object>

Decorates a SpaceDataSource with additional property, concurrent request for an iterator which is based on the same query will only open one underlying iterator against the decorates provider, this iterator will be shared amont the concurrent requests as if each of them has its own iterator. the purpose is to reduce the load on the data source.

Since:

9.5

Author:

eitany, Idan Moyal

Constructor Summary

Constructors

Constructor and Description
SharedIteratorSpaceDataSourceDecorator(SpaceDataSource spaceDataSource, long timeToLive) Create a new instance

Method Summary

Modifier and Type	Method and Description
Object	getById(DataSourceIdQuery idQuery) This method is invoked whenever the space needs to read an entry from the data source according to its Id.
DataIterator<Object>	getDataIterator(DataSourceQuery query) This method is invoked whenever the space needs to read data which matches the provided DataSourceQuery from the space data source.
DataIterator<Object>	getDataIteratorByIds(DataSourceIdsQuery idsQuery) This method is invoked whenever the space needs to read several entries from the data source according to their ids.
DataIterator<Object>	initialDataLoad() This method is invoked after SpaceDataSource.initialMetadataLoad() and is used for pre fetching data from the data source on space initialization.
DataIterator<SpaceTypeDescriptor>	initialMetadataLoad() This method is invoked on space initialization (before SpaceDataSource.initialDataLoad() is invoked) and is used for introducing data types kept in the data source to the space.
void	onClosed(SharedDataIteratorSource<Object> sender) Triggered when the iterator source is closed
void	onExpired(SharedDataIteratorSource<Object> sender) Triggered when the iterator source is expired
void	shutdown()
boolean	supportsInheritance() Determines whether this implementation supports types inheritance.

Methods inherited from class java.lang.Object

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

Constructor Detail

SharedIteratorSpaceDataSourceDecorator

public SharedIteratorSpaceDataSourceDecorator(SpaceDataSource spaceDataSource,
                                              long timeToLive)

Create a new instance

Parameters:

sqlDataProvider - provider to decorate

timeToLive - liveness time of a created mediators, once this time expired this mediator will not be used for new iterator creations

Method Detail

getDataIterator

public DataIterator<Object> getDataIterator(DataSourceQuery query)

Description copied from class: SpaceDataSource

This method is invoked whenever the space needs to read data which matches the provided DataSourceQuery from the space data source.

If this implementation doesn't supports types inheritance this method will be invoked for each type in the inheritance tree of the queried type.

The implementation's type inheritance support can be determined by overriding the SpaceDataSource.supportsInheritance() method.

Overrides:

getDataIterator in class SpaceDataSource

Parameters:

query - The DataSourceQuery to get results for.

Returns:

A DataIterator instance contains results for the provided DataSourceQuery.

shutdown

public void shutdown()
              throws DataSourceException

Throws:

DataSourceException

onClosed

public void onClosed(SharedDataIteratorSource<Object> sender)

Description copied from interface: ISharedDataIteratorSourceStateChangedListener

Triggered when the iterator source is closed

Specified by:

onClosed in interface ISharedDataIteratorSourceStateChangedListener<Object>

Parameters:

sender - shared data iterator source that triggered the event

onExpired

public void onExpired(SharedDataIteratorSource<Object> sender)

Description copied from interface: ISharedDataIteratorSourceStateChangedListener

Triggered when the iterator source is expired

Specified by:

onExpired in interface ISharedDataIteratorSourceStateChangedListener<Object>

Parameters:

sender - shared data iterator source that triggered the event

initialDataLoad

public DataIterator<Object> initialDataLoad()

Description copied from class: SpaceDataSource

This method is invoked after SpaceDataSource.initialMetadataLoad() and is used for pre fetching data from the data source on space initialization.

The returned DataIterator instance should contain POJOs or SpaceDocuments which their type was previously introduced to the space on SpaceDataSource.initialMetadataLoad() invocation.

Overrides:

initialDataLoad in class SpaceDataSource

Returns:

A DataIterator instance which contains all data to be written to Space upon its initialization - null is treated as an empty iterator.

initialMetadataLoad

public DataIterator<SpaceTypeDescriptor> initialMetadataLoad()

Description copied from class: SpaceDataSource

This method is invoked on space initialization (before SpaceDataSource.initialDataLoad() is invoked) and is used for introducing data types kept in the data source to the space.

Please note that derived types should be returned after their super types from the iterator.

It is possible to create a SpaceTypeDescriptor using SpaceTypeDescriptorBuilder.

Overrides:

initialMetadataLoad in class SpaceDataSource

Returns:

A DataIterator instance which contains all SpaceTypeDescriptor instances to be introduced to the Space upon its initialization - null is treated as an empty iterator.

getById

public Object getById(DataSourceIdQuery idQuery)

Description copied from class: SpaceDataSource

This method is invoked whenever the space needs to read an entry from the data source according to its Id.

The returned value can be either a POJO or a SpaceDocument instance.

The default implementation of this method is delegated to the SpaceDataSource.getDataIterator(DataSourceQuery) method so if the data source does not have an optimized way of reading an entity by its Id - the default implementation may suffice.

Overrides:

getById in class SpaceDataSource

Parameters:

idQuery - The DataSourceIdQuery to get a result for.

Returns:

A result from the SpaceDataSource which matches the provided DataSourceIdQuery.

getDataIteratorByIds

public DataIterator<Object> getDataIteratorByIds(DataSourceIdsQuery idsQuery)

Description copied from class: SpaceDataSource

This method is invoked whenever the space needs to read several entries from the data source according to their ids.

The returned values can be either POJOs or SpaceDocument instances.

The default implementation of this method is delegated to the SpaceDataSource.getById(DataSourceIdQuery) method for each id, so if the data source does not have an optimized way of reading an serveral entities by their ids - the default implementation may suffice.

Overrides:

getDataIteratorByIds in class SpaceDataSource

Parameters:

idsQuery - The DataSourceIdsQuery to get a result for.

Returns:

A DataIterator instance contains results for the provided DataSourceIdsQuery.

supportsInheritance

public boolean supportsInheritance()

Description copied from class: SpaceDataSource

Determines whether this implementation supports types inheritance.

If types inheritance is not supported - SpaceDataSource.getDataIterator(DataSourceQuery) will be invoked for each derived type of the query's data type. Otherwise a single SpaceDataSource.getDataIterator(DataSourceQuery) invocation will be made for the query.

Overrides:

supportsInheritance in class SpaceDataSource

Returns:

true if this SpaceDataSource implementation supports types inheritance, otherwise false.