Package com.gigaspaces.datasource.concurrentaccess

Class SharedIteratorSQLDataProviderDecorator<T>

java.lang.Object

com.gigaspaces.datasource.concurrentaccess.SharedIteratorSQLDataProviderDecorator<T>

All Implemented Interfaces:

ISharedDataIteratorSourceStateChangedListener<T>, ManagedDataSource<T>, SQLDataProvider<T>

public class SharedIteratorSQLDataProviderDecorator<T>
extends Object
implements SQLDataProvider<T>, ISharedDataIteratorSourceStateChangedListener<T>

Decorates a SQLDataProvider 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:

7.0

Author:

eitany

Field Summary

Fields inherited from interface com.gigaspaces.datasource.ManagedDataSource

NUMBER_OF_PARTITIONS, STATIC_PARTITION_NUMBER

Constructor Summary

Constructors

Constructor	Description
SharedIteratorSQLDataProviderDecorator(SQLDataProvider<T> sqlDataProvider, long timeToLive)	Create a new instance

Method Summary

Modifier and Type	Method	Description
void	init(Properties prop)	Initialize and configure the data source using given properties. Called when space is started. The properties are loaded from a file that can be defined in the space schema or as a property named: space-config.ExternalDataSource.properties-file partitionId and number of partitions are also in the Properties - can be read with STATIC_PARTITION_NUMBER and NUMBER_OF_PARTITIONS
DataIterator<T>	initialLoad()	Creates and returns an iterator over all the entries that should be loaded into space.
DataIterator<T>	iterator(SQLQuery<T> query)	Create an iterator over all objects that match the given SQLQuery.
void	onClosed(SharedDataIteratorSource<T> sender)	Triggered when the iterator source is closed
void	onExpired(SharedDataIteratorSource<T> sender)	Triggered when the iterator source is expired
void	shutdown()	Close the data source and clean any used resources. Called before space shutdown.

Methods inherited from class java.lang.Object

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

Constructor Details

SharedIteratorSQLDataProviderDecorator

public SharedIteratorSQLDataProviderDecorator(SQLDataProvider<T> sqlDataProvider,
 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 Details

iterator

public DataIterator<T> iterator(SQLQuery<T> query)
                         throws DataSourceException

Description copied from interface: SQLDataProvider

 Create an iterator over all objects that match the given SQLQuery.
 SQLQuery contains a string representation of SQL 'where' clause.
 The format matches the PreparedStatement format(field1 = ? and field2 > ? and ....).
 The prepared values are accessible by SQLQuery.getPreparedValues() method

 Example implementation with SQL PreparedStatement:

 
 PreparedStatement st = con.prepareStatement(query.getSelectAllQuery());

 int index = 0;

 if(query.hasPreparedValues())
 {
        for(Iterator iter = query.getPreparedValues().iterator();iter.hasNext())
    {
                st.setObject(++index,iter.next());
    }
 }

 ResultSet rs = st.executeQuery();

 return new ResultSetIterator(rs);
 
 

Specified by:

iterator in interface SQLDataProvider<T>

Returns:

a DataIterator or null if no data was found that match the given template

Throws:

DataSourceException

init

public void init(Properties prop)
          throws DataSourceException

Description copied from interface: ManagedDataSource

Initialize and configure the data source using given properties.
Called when space is started.
The properties are loaded from a file that can be defined in the space schema or as a property named:

space-config.ExternalDataSource.properties-file partitionId and number of partitions are also in the Properties - can be read with STATIC_PARTITION_NUMBER and NUMBER_OF_PARTITIONS

Specified by:

init in interface ManagedDataSource<T>

Parameters:

prop - - contains user defined param and Partition data

Throws:

DataSourceException

initialLoad

public DataIterator<T> initialLoad()
                            throws DataSourceException

Description copied from interface: ManagedDataSource

Creates and returns an iterator over all the entries that should be loaded into space.

Specified by:

initialLoad in interface ManagedDataSource<T>

Returns:

a DataIterator or null if no data should be loaded into space

Throws:

DataSourceException

shutdown

public void shutdown()
              throws DataSourceException

Description copied from interface: ManagedDataSource

Close the data source and clean any used resources.
Called before space shutdown.

Specified by:

shutdown in interface ManagedDataSource<T>

Throws:

DataSourceException

onClosed

public void onClosed(SharedDataIteratorSource<T> sender)

Description copied from interface: ISharedDataIteratorSourceStateChangedListener

Triggered when the iterator source is closed

Specified by:

onClosed in interface ISharedDataIteratorSourceStateChangedListener<T>

Parameters:

sender - shared data iterator source that triggered the event

onExpired

public void onExpired(SharedDataIteratorSource<T> sender)

Description copied from interface: ISharedDataIteratorSourceStateChangedListener

Triggered when the iterator source is expired

Specified by:

onExpired in interface ISharedDataIteratorSourceStateChangedListener<T>

Parameters:

sender - shared data iterator source that triggered the event