org.deegree.feature.persistence
Interface FeatureStore

All Known Implementing Classes:

MemoryFeatureStore, PostGISFeatureStore, ShapeFeatureStore, SimpleSQLDatastore

public interface FeatureStore

Base interface of the Feature persistence layer, provides access to stored Feature instances.

Note that a FeatureStore instance is always associated with exactly one ApplicationSchema instance.

Implementation requirements

Implementations must be thread-safe, because FeatureStore instances are usually used in multiple threads concurrently.

Version:

$Revision: $, $Date: $

Author:

Markus Schneider, last edited by: $Author: schneider $

Method Summary

FeatureStoreTransaction	acquireTransaction() Acquires transactional access to the feature store.
void	destroy() Called by the container to indicate that this FeatureStore instance is being taken out of service.
Envelope	getEnvelope(QName ftName) Returns the envelope for all stored features of the given type.
LockManager	getLockManager() Returns the associated LockManager.
GMLObject	getObjectById(String id) Retrieves the stored object with a certain id.
ApplicationSchema	getSchema() Returns the application schema that this FeatureStore serves.
CRS	getStorageSRS() Returns the native CRS used for storing geometries.
void	init() Called by the container to indicate that this FeatureStore instance is being placed into service.
boolean	isAvailable() Returns whether the store is currently able to perform operations.
FeatureResultSet	query(Query query) Performs the given query and returns the matching features as a FeatureResultSet.
FeatureResultSet	query(Query[] queries) Performs the given queries and returns the matching features as a FeatureResultSet.
int	queryHits(Query query) Returns the number of features that are matched by the given query.
int	queryHits(Query[] queries) Returns the number of features that are matched by the given queries.

Method Detail

init

void init()
          throws FeatureStoreException

Called by the container to indicate that this FeatureStore instance is being placed into service.

Throws:

FeatureStoreException - if the initialization fails

destroy

void destroy()

Called by the container to indicate that this FeatureStore instance is being taken out of service.

isAvailable

boolean isAvailable()

Returns whether the store is currently able to perform operations.

Returns:

true, if the store is functional, false otherwise

getSchema

ApplicationSchema getSchema()

Returns the application schema that this FeatureStore serves.

Returns:

the served application schema, never null

getStorageSRS

CRS getStorageSRS()

Returns the native CRS used for storing geometries.

Returns:

the native CRS used for storing geometries, can be null

getEnvelope

Envelope getEnvelope(QName ftName)

Returns the envelope for all stored features of the given type.

Parameters:

ftName - name of the feature type, must not be null and must be served by this store

Returns:

the envelope (using the native CRS), or null if the feature type is not known

query

FeatureResultSet query(Query query)
                       throws FeatureStoreException,
                              FilterEvaluationException

Performs the given query and returns the matching features as a FeatureResultSet.

Parameters:

query - query to be performed, must not be null

Returns:

matching features, never null

Throws:

FeatureStoreException - if the query could not be performed

FilterEvaluationException - if the filter contained in the query could not be evaluated

query

FeatureResultSet query(Query[] queries)
                       throws FeatureStoreException,
                              FilterEvaluationException

Performs the given queries and returns the matching features as a FeatureResultSet.

Parameters:

queries - queries to be performed, must not be null and contain at least one entry

Returns:

matching features, never null

Throws:

FeatureStoreException - if the query could not be performed

FilterEvaluationException - if the filter contained in the query could not be evaluated

queryHits

int queryHits(Query query)
              throws FeatureStoreException,
                     FilterEvaluationException

Returns the number of features that are matched by the given query.

Parameters:

query - query to be performed, must not be null

Returns:

number of matching featuress

Throws:

FeatureStoreException - if the query could not be performed

FilterEvaluationException - if the filter contained in the query could not be evaluated

queryHits

int queryHits(Query[] queries)
              throws FeatureStoreException,
                     FilterEvaluationException

Returns the number of features that are matched by the given queries.

Parameters:

queries - queries to be performed, must not be null and contain at least one entry

Returns:

number of matching features

Throws:

FeatureStoreException - if the query could not be performed

FilterEvaluationException - if the filter contained in the query could not be evaluated

getObjectById

GMLObject getObjectById(String id)
                        throws FeatureStoreException

Retrieves the stored object with a certain id. TODO check if a common interface for returned objects should be used here (instead of Object)

Parameters:

id - identifier of the object to be retrieved

Returns:

the stored object (either a Feature or a Geometry) or null if no object with the given id is known

Throws:

FeatureStoreException - if the query could not be performed

acquireTransaction

FeatureStoreTransaction acquireTransaction()
                                           throws FeatureStoreException

Acquires transactional access to the feature store.

Returns:

transaction object that allows to perform transactions operations on the datastore, never null

Throws:

FeatureStoreException - if the transactional access could not be acquired or is not implemented for this FeatureStore

getLockManager

LockManager getLockManager()
                           throws FeatureStoreException

Returns the associated LockManager.

Returns:

the associated LockManager instance, never null

Throws:

FeatureStoreException - if the FeatureStore does not implement locking