Application: gvSIG desktop

/**

 * gvSIG. Desktop Geographic Information System.

 *

 * Copyright (C) 2007-2013 gvSIG Association.

 *

 * This program is free software; you can redistribute it and/or

 * modify it under the terms of the GNU General Public License

 * as published by the Free Software Foundation; either version 3

 * of the License, or (at your option) any later version.

 *

 * This program is distributed in the hope that it will be useful,

 * but WITHOUT ANY WARRANTY; without even the implied warranty of

 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the

 * GNU General Public License for more details.

 *

 * You should have received a copy of the GNU General Public License

 * along with this program; if not, write to the Free Software

 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston,

 * MA  02110-1301, USA.

 *

 * For any additional information, do not hesitate to contact us

 * at info AT gvsig.com, or visit our website www.gvsig.com.

 */

package org.gvsig.fmap.dal.feature;

import java.util.Iterator;

import java.util.List;

import org.cresques.cts.IProjection;

import org.gvsig.expressionevaluator.Expression;

import org.gvsig.expressionevaluator.ExpressionBuilder;

import org.gvsig.fmap.dal.DataServerExplorer;

import org.gvsig.fmap.dal.DataStore;

import org.gvsig.fmap.dal.DataStoreParameters;

import org.gvsig.fmap.dal.StoresRepository;

import org.gvsig.fmap.dal.exception.DataException;

import org.gvsig.fmap.dal.exception.ReadException;

import org.gvsig.fmap.dal.feature.exception.FeatureIndexException;

import org.gvsig.fmap.dal.feature.exception.NeedEditingModeException;

import org.gvsig.fmap.geom.Geometry;

import org.gvsig.fmap.geom.SpatialIndex;

import org.gvsig.fmap.geom.primitive.Envelope;

import org.gvsig.tools.dispose.DisposableIterator;

import org.gvsig.tools.dynobject.DynObject;

import org.gvsig.tools.lang.Cloneable;

import org.gvsig.tools.observer.Observer;

import org.gvsig.tools.undo.UndoRedoStack;

import org.gvsig.tools.util.ResourcesStorage;

/**

 * <p>

 * A FeatureStore is a type of store whose data consists on sets of

 * {@link Feature}(s). {@link Feature}(s) from the same FeatureStore can be of

 * different {@link FeatureType}(s) (as in GML format for instance).

 * </p>

 *

 * <p>

 * FeatureStore allows:

 * </p>

 * <ul>

 * <li>Obtaining the default {@link FeatureType}. A FeatureStore always has one

 * and only one default FeatureType.

 * <li>Obtaining the list of {@link FeatureType}(s) defined in the FeatureStore.

 * <li>Obtaining, filtering and sorting subsets of data ({@link FeatureSet})

 * through {@link FeatureQuery}, as well as background loading.

 * <li>Obtaining the total {@link Envelope} (AKA bounding box or extent) of the

 * store.

 * <li>Support for editing {@link FeatureType}(s).

 * <li>Obtaining information about contained {@link Geometry} types.

 * <li>Exporting to another store.

 * <li>Indexing.

 * <li>Selection.

 * <li>Locks management.

 * </ul>

 *

 */

public interface FeatureStore extends DataStore, UndoRedoStack, Cloneable {

    public static final String METADATA_DEFINITION_NAME = "FeatureStore";

    /** Indicates that this store is in query mode */

    final static int MODE_QUERY = 0;

    /** Indicates that this store is in full edit mode */

    final static int MODE_FULLEDIT = 1;

    /** Indicates that this store is in append mode */

    final static int MODE_APPEND = 2;

    /*

     * =============================================================

     *

     * information related services

     */

    /**

     * Indicates whether this store allows writing.

     *

     * @return

     *         true if this store can be written, false if not.

     */

    public boolean allowWrite();

    /**

     * Returns this store's default {@link FeatureType}.

     *

     * @return

     *         this store's default {@link FeatureType}.

     *

     * @throws DataException

     */

    public FeatureType getDefaultFeatureType() throws DataException;

    /**

     * Returns this store's featureType {@link FeatureType} matches with

     * featureTypeId.

     *

     * @param featureTypeId

     *

     * @return this store's default {@link FeatureType}.

     *

     * @throws DataException

     */

    public FeatureType getFeatureType(String featureTypeId)

        throws DataException;

    /**

     * Returns this store's {@link FeatureType}(s).

     *

     * @return a list with this store's {@link FeatureType}(s).

     *

     * @throws DataException

     */

    public List getFeatureTypes() throws DataException;

    /**

     * Returns this store's parameters.

     *

     * @return

     *         {@link DataStoreParameters} containing this store's parameters

     */

    public DataStoreParameters getParameters();

    /**

     *@throws DataException

     * @deprecated Mirar de cambiarlo a metadatos

     */

    public boolean canWriteGeometry(int gvSIGgeometryType) throws DataException;

    /**

     * Returns this store's total envelope (extent).

     *

     * @return this store's total envelope (extent) or <code>null</code> if

     *         store not have geometry information

     */

    public Envelope getEnvelope() throws DataException;

    /**

     *

     * @deprecated use getDefaultFeatureType().getDefaultSRS()

     * @return

     * @throws DataException

     */

    public IProjection getSRSDefaultGeometry() throws DataException;

    /**

     * Exports this store to another store.

     *

     * @param explorer

     *            {@link DataServerExplorer} target

     * @param params

     *            New parameters of this store that will be used on the target

     *            explorer

     *

     * @throws DataException

     *

     * @Deprecated this method is unstable

     */

    public void export(DataServerExplorer explorer, String provider,

        NewFeatureStoreParameters params) throws DataException;

    /*

     * =============================================================

     *

     * Query related services

     */

    /**

     * Returns all available features in the store.

     * <p>

     * <em>

     * <strong>NOTE:</strong> if you use this method to get a

     * {@link FeatureSet}, you  must get sure it is disposed

     * (@see {@link DisposableIterator#dispose()}) in any case, even if an

     * error occurs while getting the data. It is recommended to use the

     * <code>accept</code> methods instead, which handle everything for you.

     * Take into account the accept methods may use a fast iterator to

     * get the features.

     * </em>

     * </p>

     *

     * @see #accept(org.gvsig.tools.visitor.Visitor)

     *

     * @return a collection of features

     * @throws ReadException

     *             if there is any error while reading the features

     */

    FeatureSet getFeatureSet() throws DataException;

    FeatureSet getFeatureSet(String filter) throws DataException;

    FeatureSet getFeatureSet(String filter, String sortBy) throws DataException;

    FeatureSet getFeatureSet(String filter, String sortBy, boolean asc) throws DataException;

    FeatureSet getFeatureSet(Expression filter) throws DataException;

    FeatureSet getFeatureSet(Expression filter, String sortBy) throws DataException;

    FeatureSet getFeatureSet(Expression filter, String sortBy, boolean asc) throws DataException;

    /**

     * Returns a subset of features taking into account the properties and

     * restrictions of the FeatureQuery.

     * <p>

     * <em>

     * <strong>NOTE:</strong> if you use this method to get a

     * {@link FeatureSet}, you  must get sure it is disposed

     * (@see {@link DisposableIterator#dispose()}) in any case, even if an

     * error occurs while getting the data. It is recommended to use the

     * <code>accept</code> methods instead, which handle everything for you.

     * Take into account the accept methods may use a fast iterator to

     * get the features.

     * </em>

     * </p>

     *

     * @see #accept(org.gvsig.tools.visitor.Visitor,

     *      org.gvsig.fmap.dal.DataQuery)

     *

     * @param featureQuery

     *            defines the characteristics of the features to return

     * @return a collection of features

     * @throws ReadException

     *             if there is any error while reading the features

     */

    FeatureSet getFeatureSet(FeatureQuery featureQuery) throws DataException;

    /**

     * Loads a subset of features taking into account the properties and

     * restrictions of the FeatureQuery. Feature loading is performed by calling

     * the Observer, once each loaded Feature.

     *

     * @param featureQuery

     *            defines the characteristics of the features to return

     * @param observer

     *            to be notified of each loaded Feature

     * @throws DataException

     *             if there is any error while loading the features

     */

    void getFeatureSet(FeatureQuery featureQuery, Observer observer)

        throws DataException;

    /**

     * Loads all available feature in the store. The loading of Features is

     * performed by calling the Observer, once each loaded Feature.

     *

     * @param observer

     *            to be notified of each loaded Feature

     * @throws DataException

     *             if there is any error while loading the features

     */

    void getFeatureSet(Observer observer) throws DataException;

    /**

     * Return a paginated list of Features filtered by the query.

     *

     * The returned List of Features is paginated, and the page size

     * used is "pageSize".

     *

     * @param query to filter the returned feature list

     * @param pageSize the page size of the list

     * @return the list of features

     */

    public List<Feature> getFeatures(FeatureQuery query, int pageSize);

    public List<Feature> getFeatures(FeatureQuery query);

    public List<Feature> getFeatures();

    public List<Feature> getFeatures(String filter);

    public List<Feature> getFeatures(String filter, String sortBy);

    public List<Feature> getFeatures(String filter, String sortBy, boolean asc);

    public List<Feature> getFeatures(Expression filter);

    public List<Feature> getFeatures(Expression filter, String sortBy);

    public List<Feature> getFeatures(Expression filter, String sortBy, boolean asc);

    public Feature first() throws DataException;

    public Feature findFirst(String filter) throws DataException;

    public Feature findFirst(String filter, String sortBy) throws DataException;

    public Feature findFirst(String filter, String sortBy, boolean asc) throws DataException;

    public Feature findFirst(Expression filter) throws DataException;

    public Feature findFirst(Expression filter, String sortBy) throws DataException;

    public Feature findFirst(Expression filter, String sortBy, boolean asc) throws DataException;

    public Feature findFirst(FeatureQuery query) throws DataException;

    /**

     * Returns the feature given its reference.

     *

     * @param reference

     *            a unique FeatureReference

     * @return

     *         The Feature

     *

     * @throws DataException

     *

     */

    public Feature getFeatureByReference(FeatureReference reference)

        throws DataException;

    /**

     * Returns the feature given its reference and feature type.

     *

     * @param reference

     *            a unique FeatureReference

     *

     * @param featureType

     *            FeatureType to which the requested Feature belongs

     *

     * @return

     *         The Feature

     *

     * @throws DataException

     *

     */

    public Feature getFeatureByReference(FeatureReference reference,

        FeatureType featureType) throws DataException;

    /*

     * =============================================================

     *

     * Editing related services

     */

    /**

     * Enters editing state.

     */

    public void edit() throws DataException;

    /**

     * Enters editing state specifying the editing mode.

     *

     * @param mode

     *

     * @throws DataException

     */

    public void edit(int mode) throws DataException;

    /**

     * Cancels all editing since the last edit().

     *

     * @throws DataException

     */

    public void cancelEditing() throws DataException;

    /**

     * Exits editing state.

     *

     * @throws DataException

     */

    public void finishEditing() throws DataException;

    /**

     * Save changes in the provider without leaving the edit mode.

     * Do not call observers to communicate a change of ediding mode.

     * The operation's history is eliminated to prevent inconsistencies

     * in the data.

     *

     * @throws DataException

     */

    public void commitChanges() throws DataException ;

    /**

     *

     * Returns true if you can call CommitChanges method.

     * If not in editing or changes have been made in the structure

     * return false.

     *

     * @return true if can call commitChanges

     * @throws DataException

     */

    public boolean canCommitChanges() throws DataException;

    /**

     * Indicates whether this store is in editing state.

     *

     * @return

     *         true if this store is in editing state, false if not.

     */

    public boolean isEditing();

    /**

     * Indicates whether this store is in appending state. In this state the new

     * features are automatically inserted at the end of the {@link FeatureSet}.

     *

     * @return true if this store is in appending state.

     */

    public boolean isAppending();

    /**

     * Updates a {@link FeatureType} in the store with the changes in the

     * {@link EditableFeatureType}.<br>

     *

     * Any {@link FeatureSet} from this store that are used will be invalidated.

     *

     * @param featureType

     *            an {@link EditableFeatureType} with the changes.

     *

     * @throws DataException

     */

    public void update(EditableFeatureType featureType) throws DataException;

    /**

     * Updates a {@link Feature} in the store with the changes in the

     * {@link EditableFeature}.<br>

     *

     * Any {@link FeatureSet} from this store that was still in use will be

     * invalidated. You can override this using

     * {@link FeatureSet#update(EditableFeature)}.

     *

     * @param feature

     *            the feature to be updated

     *

     * @throws DataException

     */

    public void update(EditableFeature feature) throws DataException;

    /**

     * Deletes a {@link Feature} from the store.<br>

     *

     * Any {@link FeatureSet} from this store that was still in use will be

     * invalidated. You can override this using {@link Iterator#remove()} from

     * {@link FeatureSet}.

     *

     * @param feature

     *            The feature to be deleted.

     *

     * @throws DataException

     */

    public void delete(Feature feature) throws DataException;

    /**

     * Inserts a {@link Feature} in the store.<br>

     *

     * Any {@link FeatureSet} from this store that was still in use will be

     * invalidated. You can override this using

     * {@link FeatureSet#insert(EditableFeature)}.

     *

     * @param feature

     *            The feature to be inserted

     *

     * @throws DataException

     */

    public void insert(EditableFeature feature) throws DataException;

    /**

     * Creates a new feature using the default feature type and returns it as an

     * {@link EditableFeature}

     *

     * @return a new feature in editable state

     *

     * @throws DataException

     */

    public EditableFeature createNewFeature() throws DataException;

    /**

     * Creates a new feature of the given {@link FeatureType} and uses the given

     * {@link Feature} as default values to initialize it.

     *

     * @param type

     *            the new feature's feature type

     *

     * @param defaultValues

     *            a feature whose values are used as default values for the new

     *            feature.

     *

     * @return the new feature.

     *

     * @throws DataException

     */

    public EditableFeature createNewFeature(FeatureType type,

        Feature defaultValues) throws DataException;

    /**

     * Creates a new feature of the given {@link FeatureType}. The flag

     * defaultValues is used to indicate whether the new feature should be

     * initialized with default values or not.

     *

     * @param type

     *            the new feature's feature type

     *

     * @param defaultValues

     *            if true the new feature is initialized with each attribute's

     *            default value.

     *

     * @return

     *         the new feature

     *

     * @throws DataException

     */

    public EditableFeature createNewFeature(FeatureType type,

        boolean defaultValues) throws DataException;

    /**

     * Creates a new feature of default {@link FeatureType}. The flag

     * defaultValues is used to indicate whether the new feature should be

     * initialized with default values or not.

     *

     * @param defaultValues

     *            if true the new feature is initialized with each attribute's

     *            default value.

     *

     * @return

     *         the new feature

     *

     * @throws DataException

     */

    public EditableFeature createNewFeature(boolean defaultValues)

        throws DataException;

    /**

     * Creates a new feature of default {@link FeatureType}.

     * The new feature should be initialized with the values of the feature

     * passed as parameter.

     * Values are inicialiced by name from the feature specified. Error in

     * value assignement are ignoreds.

     *

     * @param defaultValues the values to initialize the new feature.

     * @return the new feature

     * @throws DataException

     */

    public EditableFeature createNewFeature(Feature defaultValues)

        throws DataException;

    /**

     * Applies the validation rules associated to the given mode to the active

     * {@link FeatureSet}.

     *

     * @param mode

     *            can be one of {MODE_QUERY, MODE_FULLEDIT, MODE_APPEND}

     *

     * @throws DataException

     */

    public void validateFeatures(int mode) throws DataException;

    /**

     * Indicates whether this store supports append mode.

     *

     * @return

     *         true if this store supports append mode.

     */

    public boolean isAppendModeSupported();

    /**

     * Initiates an editing group. This is typically used to group series of

     * store editing operations.

     *

     * @param description

     *            Description of the editing group.

     *

     * @throws NeedEditingModeException

     */

    public void beginEditingGroup(String description)

        throws NeedEditingModeException;

    /**

     * Finishes an editing group.

     *

     * @throws NeedEditingModeException

     */

    public void endEditingGroup() throws NeedEditingModeException;

    /*

     * =============================================================

     *

     * Index related services

     */

    /**

     * Creates an index which will be applied to the features of the given type,

     * by using the data of the given attribute.

     *

     * @param featureType

     *            The FeatureType to which the indexed attribute belongs.

     *

     * @param attributeName

     *            The name of the attributed to be indexed

     *

     * @param indexName

     *            The index name

     *

     * @return the resulting {@link FeatureIndex}

     *

     *

     * @throws FeatureIndexException

     *             if there is an error creating the index

     */

    public FeatureIndex createIndex(FeatureType featureType,

        String attributeName, String indexName) throws DataException;

    /**

     * Creates an index which will be applied to the features of the given type,

     * by using the data of the given attribute.

     *

     * @param indexTypeName

     *            the type of the index to be created. That name is

     *            related to one of the registered index providers

     * @param featureType

     *            The FeatureType to which the indexed attribute belongs.

     *

     * @param attributeName

     *            The name of the attributed to be indexed

     *

     * @param indexName

     *            The index name

     *

     * @return the resulting {@link FeatureIndex}

     *

     *

     * @throws FeatureIndexException

     *             if there is an error creating the index

     */

    public FeatureIndex createIndex(String indexTypeName,

        FeatureType featureType, String attributeName, String indexName)

        throws DataException;

    /**

     * Creates an index which will be applied to the features of the given type,

     * by using the data of the given attribute. This method will return without

     * waiting for the index to be filled, as that will be performed in

     * background. An optional {@link Observer} parameter is provided to be

     * notified ( {@link FeatureStoreNotification#INDEX_FILLING_SUCCESS} )

     * when the index has finished filling with data and is available to be

     * used.

     *

     * @param featureType

     *            The FeatureType to which the indexed attribute belongs.

     *

     * @param attributeName

     *            The name of the attributed to be indexed

     *

     * @param indexName

     *            The index name

     *

     * @param observer

     *            to notify to when the created index has finished filling

     *            with data and is available to be used. The observer will

     *            receive then a

     *            {@link FeatureStoreNotification#INDEX_FILLING_SUCCESS}

     *            notification, with the index object if it has finished

     *            successfully, or a

     *            {@link FeatureStoreNotification#INDEX_FILLING_ERROR}

     *            notification with the exception object if there has been

     *            any error in the process. Optional.

     *

     * @return the resulting {@link FeatureIndex}

     *

     * @see FeatureStoreNotification#INDEX_FILLING_STARTED

     * @see FeatureStoreNotification#INDEX_FILLING_SUCCESS

     * @see FeatureStoreNotification#INDEX_FILLING_CANCELLED

     * @see FeatureStoreNotification#INDEX_FILLING_ERROR

     *

     * @throws FeatureIndexException

     *             if there is an error creating the index

     */

    public FeatureIndex createIndex(FeatureType featureType,

        String attributeName, String indexName, Observer observer)

        throws DataException;

    /**

     * Creates an index which will be applied to the features of the given type,

     * by using the data of the given attribute. This method will return without

     * waiting for the index to be filled, as that will be performed in

     * background. An optional {@link Observer} parameter is provided to be

     * notified ( {@link FeatureStoreNotification#INDEX_FILLING_SUCCESS} )

     * when the index has finished filling with data and is available to be

     * used.

     *

     * @param indexTypeName

     *            the type of the index to be created. That name is

     *            related to one of the registered index providers

     * @param featureType

     *            The FeatureType to which the indexed attribute belongs.

     *

     * @param attributeName

     *            The name of the attributed to be indexed

     *

     * @param indexName

     *            The index name

     *

     * @param observer

     *            to notify to when the created index has finished filling

     *            with data and is available to be used. The observer will

     *            receive then a

     *            {@link FeatureStoreNotification#INDEX_FILLING_SUCCESS}

     *            notification, with the index object if it has finished

     *            successfully, or a

     *            {@link FeatureStoreNotification#INDEX_FILLING_ERROR}

     *            notification with the exception object if there has been

     *            any error in the process. Optional.

     *

     * @return the resulting {@link FeatureIndex}

     *

     * @see FeatureStoreNotification#INDEX_FILLING_STARTED

     * @see FeatureStoreNotification#INDEX_FILLING_SUCCESS

     * @see FeatureStoreNotification#INDEX_FILLING_CANCELLED

     * @see FeatureStoreNotification#INDEX_FILLING_ERROR

     *

     * @throws FeatureIndexException

     *             if there is an error creating the index

     */

    public FeatureIndex createIndex(String indexTypeName,

        FeatureType featureType, String attributeName, String indexName,

        Observer observer) throws DataException;

    /**

     * Returns a FeatureIndexes structure containing all available indexes in

     * the store.

     *

     * @return

     */

    public FeatureIndexes getIndexes();

    /*

     * =============================================================

     *

     * Selection related services

     */

    /**

     * Sets the selection to the passed {@link FeatureSet}

     *

     * @param selection

     *            A {@link FeatureSet} with the requested selection

     */

    public void setSelection(FeatureSet selection) throws DataException;

    /**

     * Creates a {@link FeatureSelection}

     *

     * @return

     *         a {@link FeatureSelection}

     *

     * @throws DataException

     */

    public FeatureSelection createFeatureSelection() throws DataException;

    /**

     * Returns the current {@link FeatureSelection}.

     * Create a empty selection if not exits.

     * 

     * Manage of the selection can be slow on some data sources. 

     * Use with care.

     * In data sources that do not support position access to records, 

     * it may be slow to retrieve items from the selection. In some data 

     * sources it may be necessary to access to this to retrieve each 

     * item in the selection.

     *

     * @return

     *         current {@link FeatureSelection}.

     *

     * @throws DataException

     */

    public FeatureSelection getFeatureSelection() throws DataException;

    /*

     * =============================================================

     *

     * Lock related services

     */

    /**

     * Indicates whether this store supports locks.

     *

     * @return

     *         true if this store supports locks, false if not.

     */

    public boolean isLocksSupported();

    /**

     * Returns the set of locked features

     *

     * @return

     *         set of locked features

     *

     * @throws DataException

     */

    public FeatureLocks getLocks() throws DataException;

    /*

     * =============================================================

     * Transforms related services

     * =============================================================

     */

    /**

     * Returns this store transforms

     *

     * @return

     *         this store transforms

     */

    public FeatureStoreTransforms getTransforms();

    /**

     * Returns a new {@link FeatureQuery} associated to this store.

     *

     * @return

     *         a new {@link FeatureQuery} associated to this store.

     */

    public FeatureQuery createFeatureQuery();

    /**

     * Returns featue count of this store.

     *

     * @return

     * @throws DataException

     */

    public long getFeatureCount() throws DataException;

//    /**

//     * Creates a vectorial cache that is used to save and retrieve data.

//     *

//     * @param name

//     *            the cache name.

//     * @param parameters

//     *            parameters to create the stores used to save data.

//     * @throws DataException

//     */

//    public void createCache(String name, DynObject parameters)

//        throws DataException;

//

//    /**

//     * @return the vectorial cache

//     */

//    public FeatureCache getCache();

    /**

     * Return if the provider knows the real envelope of a layer. If not,

     * the {@link FeatureStoreProvider#getEnvelope()} method doesn't return

     * the full envelope.

     *

     * @return

     *         <true> if it knows the real envelope.

     */

    public boolean isKnownEnvelope();

    /**

     * Return if the maximum number of features provided by the

     * provider are limited.

     *

     * @return

     *         <true> if there is a limit of features.

     */

    public boolean hasRetrievedFeaturesLimit();

    /**

     * If the {@link FeatureStoreProvider#hasRetrievedFeaturesLimit()} returns

     * true,

     * it returns the limit of features retrieved from the provider.

     *

     * @return

     *         The limit of the retrieved features.

     */

    public int getRetrievedFeaturesLimit();

    /**

     * Return the associated feature to the dynobject.

     * If the dynobject isn't associated to a feature of this store, return null.

     *

     * @param dynobject

     * @return

     */

    public Feature getFeature(DynObject dynobject);

    public Iterator iterator();

    public ExpressionBuilder createExpressionBuilder();

    /**

     * 

     * @return 

     * @deprecated use createExpressionBuilder

     */

    public ExpressionBuilder createExpression();

    public void createCache(String name, DynObject parameters)

        throws DataException;

    public FeatureCache getCache();

    public boolean isBroken();

        public Throwable getBreakingsCause();

    /**

     * @param index

     * @return

     */

    public SpatialIndex wrapSpatialIndex(SpatialIndex index);

    public FeatureReference getFeatureReference(String code);

    /**

     * Devuelbe el numero de operaciones pendientes de guardar en una sesion

     * de edicion. Es un valor orientativo.

     * Las operaciones pendientes son la suma de operaciones de borrado, insercion

     * o modificacion de las features en una sesion de edicion.

     * 

     * Retorna 0 si no esta en edicion.

     * 

     * @return numero de operaciones pendientes. 

     */

    public long getPendingChangesCount();

    public ResourcesStorage getResourcesStorage();

    public StoresRepository getStoresRepository();

}