org.deegree.io.datastore
Class Datastore

java.lang.Object
  org.deegree.io.datastore.Datastore

Direct Known Subclasses:

AbstractSQLDatastore, CachedWFSDatastore, CascadingWFSDatastore, SDEDatastore, ShapeDatastore

public abstract class Datastore
extends Object

A datastore implementation must extend this class.

Describes the access to a datastore that encapsulates the access to a database or file. The accessible objects are Feature instances. Primarily, datastores are used as persistence layer by the WFService class.

Version:

$Revision: 18195 $, $Date: 2009-06-18 17:55:39 +0200 (Do, 18. Jun 2009) $

Author:

Andreas Poth , Torsten Friebe , Markus Schneider , last edited by: $Author: mschneider $

Constructor Summary

Datastore()

Method Summary

DatastoreTransaction	acquireTransaction() Acquires transactional access to the datastore instance.
void	bindSchema(MappedGMLSchema schema) Adds the given GML application schema to the set of schemas that are handled by this datastore instance.
protected boolean	canTransformTo(String targetSRS) Returns whether the datastore is capable of performing a native coordinate transformation (using an SQL function call for example) into the given SRS.
abstract void	close() Closes the datastore so it can free dependent resources.
void	configure(DatastoreConfiguration config) Configures the datastore with the supplied configuration.
Set<FeatureId>	determineFidsToLock(List<Lock> requestParts) Determines the ids of all features to be locked by the given parts of a LockFeature request, this includes all descendant and super features of the targeted features as well.
abstract AnnotationDocument	getAnnotationParser() Returns the datastore specific annotation parser.
DatastoreConfiguration	getConfiguration() Returns the configuration parameters of the datastore.
MappedFeatureType	getFeatureType(QualifiedName ftName) Returns the feature type with the given name.
MappedGMLSchema[]	getSchemas() Returns the GML application schemas that are handled by this datastore.
abstract FeatureCollection	performQuery(Query query, MappedFeatureType[] rootFts) Performs a query against the datastore.
abstract FeatureCollection	performQuery(Query query, MappedFeatureType[] rootFts, DatastoreTransaction context) Performs a query against the datastore (in the given transaction context).
void	releaseTransaction(DatastoreTransaction ta) Returns the transaction to the datastore.
protected Query	transformQuery(Query query) Transforms the incoming Query so that the CoordinateSystem of all spatial arguments (BBOX, etc.) in the Filter match the SRS of the targeted MappingGeometryFields.
protected FeatureCollection	transformResult(FeatureCollection fc, String targetSRS) Transforms the FeatureCollection so that the geometries of all contained geometry properties use the requested SRS.

Methods inherited from class java.lang.Object

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

Constructor Detail

Datastore

public Datastore()

Method Detail

getAnnotationParser

public abstract AnnotationDocument getAnnotationParser()

Returns the datastore specific annotation parser.

Returns:

the datastore specific annotation parser

configure

public void configure(DatastoreConfiguration config)
               throws DatastoreException

Configures the datastore with the supplied configuration.

Parameters:

config - configuration

Throws:

DatastoreException

getConfiguration

public DatastoreConfiguration getConfiguration()

Returns the configuration parameters of the datastore.

Returns:

the configuration parameters of the datastore

bindSchema

public void bindSchema(MappedGMLSchema schema)
                throws DatastoreException

Adds the given GML application schema to the set of schemas that are handled by this datastore instance.

Note that this method may be called several times for every GML schema that uses this datastore instance.

Parameters:

schema - GML application schema to bind

Throws:

DatastoreException

getSchemas

public MappedGMLSchema[] getSchemas()

Returns the GML application schemas that are handled by this datastore.

Returns:

the GML application schemas that are handled by this datastore

getFeatureType

public MappedFeatureType getFeatureType(QualifiedName ftName)

Returns the feature type with the given name.

Parameters:

ftName - name of the feature type

Returns:

the feature type with the given name, or null if the Datastore does not this feature type

close

public abstract void close()
                    throws DatastoreException

Closes the datastore so it can free dependent resources.

Throws:

DatastoreException

performQuery

public abstract FeatureCollection performQuery(Query query,
                                               MappedFeatureType[] rootFts)
                                        throws DatastoreException,
                                               UnknownCRSException

Performs a query against the datastore.

Parameters:

query - query to be performed

rootFts - the root feature types that are queried, more than one type means that the types are joined

Returns:

requested feature instances

Throws:

DatastoreException

UnknownCRSException

performQuery

public abstract FeatureCollection performQuery(Query query,
                                               MappedFeatureType[] rootFts,
                                               DatastoreTransaction context)
                                        throws DatastoreException,
                                               UnknownCRSException

Performs a query against the datastore (in the given transaction context).

Parameters:

query - query to be performed

rootFts - the root feature types that are queried, more than one type means that the types are joined

context - context (used to specify the JDBCConnection, for example)

Returns:

requested feature instances

Throws:

DatastoreException

UnknownCRSException

determineFidsToLock

public Set<FeatureId> determineFidsToLock(List<Lock> requestParts)
                                   throws DatastoreException

Determines the ids of all features to be locked by the given parts of a LockFeature request, this includes all descendant and super features of the targeted features as well.

Parameters:

requestParts - the parts of a LockFeature request that this Datastore is responsible for

Returns:

the ids of all features that have to be locked

Throws:

DatastoreException

acquireTransaction

public DatastoreTransaction acquireTransaction()
                                        throws DatastoreException

Acquires transactional access to the datastore instance. There's only one active transaction per datastore allowed.

Returns:

transaction object that allows to perform transactions operations on the datastore

Throws:

DatastoreException

releaseTransaction

public void releaseTransaction(DatastoreTransaction ta)
                        throws DatastoreException

Returns the transaction to the datastore. This makes the transaction available to other clients again (via acquireTransaction()). Underlying resources (such as JDBCConnections are freed).

The transaction should be terminated, i.e. DatastoreTransaction.commit() or DatastoreTransaction.rollback() must have been called before.

Parameters:

ta - the DatastoreTransaction to be returned

Throws:

DatastoreException

transformQuery

protected Query transformQuery(Query query)

Transforms the incoming Query so that the CoordinateSystem of all spatial arguments (BBOX, etc.) in the Filter match the SRS of the targeted MappingGeometryFields.

NOTE: If this transformation can be performed by the backend (e.g. by Oracle Spatial), this method should be overwritten to return the original input Query.

Parameters:

query - query to be transformed

Returns:

query with spatial arguments transformed to target SRS

transformResult

protected FeatureCollection transformResult(FeatureCollection fc,
                                            String targetSRS)

Transforms the FeatureCollection so that the geometries of all contained geometry properties use the requested SRS.

Parameters:

fc - feature collection to be transformed

targetSRS - requested SRS

Returns:

transformed FeatureCollection

canTransformTo

protected boolean canTransformTo(String targetSRS)

Returns whether the datastore is capable of performing a native coordinate transformation (using an SQL function call for example) into the given SRS.

Datastore implementations capable of performing native coordinate transformations must override this class.

Parameters:

targetSRS - target spatial reference system (usually "EPSG:XYZ")

Returns:

true, if the datastore can perform the coordinate transformation, false otherwise