org.deegree.feature.persistence
Interface FeatureStore

All Superinterfaces:

Resource

All Known Implementing Classes:

GeoCouchFeatureStore, MemoryFeatureStore, RemoteWFSFeatureStore, ShapeFeatureStore, SimpleSQLFeatureStore, SQLFeatureStore

public interface FeatureStore
extends Resource

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

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

NOTE: Implementations must be thread-safe, as 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.
Envelope	calcEnvelope(QName ftName) Recalculates the envelope for all stored features of the given type.
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.
AppSchema	getSchema() Returns the application schema that this FeatureStore serves.
boolean	isAvailable() Returns whether the store is currently able to perform operations.
FeatureInputStream	query(Query query) Performs the given query and returns the matching features as a FeatureInputStream.
FeatureInputStream	query(Query[] queries) Performs the given queries and returns the matching features as a FeatureInputStream.
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.

Methods inherited from interface org.deegree.commons.config.Resource

destroy, init

Method Detail

isAvailable

boolean isAvailable()

Returns whether the store is currently able to perform operations.

Returns:

true, if the store is functional, false otherwise

getSchema

AppSchema getSchema()

Returns the application schema that this FeatureStore serves.

Returns:

the served application schema, never null

getEnvelope

Envelope getEnvelope(QName ftName)
                     throws FeatureStoreException

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

NOTE: This method may return incorrect (cached) results. Use calcEnvelope(QName) to force the recalculation of the Envelope.

Parameters:

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

Returns:

the envelope (using the storage CRS), or null if the feature type does not have an envelope (no geometry properties or no instances)

Throws:

FeatureStoreException

calcEnvelope

Envelope calcEnvelope(QName ftName)
                      throws FeatureStoreException

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

NOTE: This method may potentially be expensive. Depending on the implementation, it may involve fetching all features of the specified type.

Parameters:

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

Returns:

the envelope (using the storage CRS), or null if the feature type does not have an envelope (no geometry properties or no instances)

Throws:

FeatureStoreException

query

FeatureInputStream query(Query query)
                         throws FeatureStoreException,
                                FilterEvaluationException

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

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

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

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

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, one entry per query

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.

Parameters:

id - identifier of the object to be retrieved

Returns:

the stored object (currently 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, or null if the FeatureStore does not implement locking

Throws:

FeatureStoreException - if the lock manager could not be acquired