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package org.gvsig.fmap.dal;

import java.util.Iterator;

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

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

import org.gvsig.metadata.Metadata;

import org.gvsig.tools.dispose.Disposable;

import org.gvsig.tools.exception.BaseException;

import org.gvsig.tools.observer.ComplexWeakReferencingObservable;

import org.gvsig.tools.observer.Observer;

import org.gvsig.tools.persistence.Persistent;

import org.gvsig.tools.visitor.Visitable;

import org.gvsig.tools.visitor.Visitor;

/**

 * <p>

 * This is the basic interface for all data stores. Depending on the context, it

 * can represent a geographic layer, an alphanumeric database table or any data

 * file. DataStore offers generic services like:

 * <ul>

 * <li>Open and close data stores</li>

 * <li>Access to data sets, with the possibility of loading data in background.</li>

 * <li>Use of selection and locks, as well as data sets</li>

 * <li>Editing</li>

 * <li>Register event observers through the Observable interface</li>

 * <li>Access to embedded data stores (like GML)</li>

 * <li>Information about the Spatial Reference Systems used by the data store</li>

 * </ul>

 * </p>

 * <br>

 *

 */

public interface DataStore extends ComplexWeakReferencingObservable,

                Persistent, Metadata, Disposable, Visitable {

        public static final String METADATA_DEFINITION_NAME = "DataProvider";

        public static final String FEATURE_METADATA_DEFINITION_NAME = "FeatureProvider";

        public static final String SPATIAL_METADATA_DEFINITION_NAME = "SpatialProvider";

        /**

         * Metadata property name for the provider name provided by the data provider.

         * 

         * This metadata is provided by all data providers.

         */

        public static final String METADATA_PROVIDER = "ProviderName";

        /**

         * Metadata property name for Container name provided by the data provider.

         * By explample, in a dbf file, this is the name of dbf.

         * 

         * This metadata is provided by all data providers.

         */

        public static final String METADATA_CONTAINERNAME = "ContainerName";

        /**

         * Metadata property name for the feature type provided by the data provider.

         * 

         * This metadata is provided by all tabular data providers.

         */

        public static final String METADATA_FEATURETYPE = "FeatureType";

        /**

         * Metadata property name for CRS provided by the data provider.

         * 

         * This metadata is only provided by data provider with spatial 

         * information.

         */

        public static final String METADATA_CRS = "CRS";

        /**

         * Metadata property name for Envelope provided by the data provider

         * 

         * This metadata is only provided by data provider with spatial 

         * information.

         */

        public static final String METADATA_ENVELOPE = "Envelope";

        /**

         * Returns this store's name.

         *

         * @return String containing this store's name.

         */

        public String getName();

        /**

         * Return the of parameters of this store

         *

         * @return parameters of this store

         */

        public DataStoreParameters getParameters();

        /**

         * Return the provider name that use this store.

         * 

         * @return provider name of this store

         */

        public String getProviderName();

        /**

         * Refreshes this store state.

         *

         * @throws DataException

         */

        public void refresh() throws DataException;

        /**

         * Returns all available data.

         *

         * @return a set of data

         * @throws DataException

         *             if there is any error while loading the data

         */

        DataSet getDataSet() throws DataException;

        /**

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

         * restrictions of the DataQuery.

         *

         * @param dataQuery

         *            defines the properties of the requested data

         * @return a set of data

         * @throws DataException

         *             if there is any error while loading the data

         */

        DataSet getDataSet(DataQuery dataQuery) throws DataException;

        /**

         * Provides each value of this container to the provided {@link Visitor}.

         * 

         * @param visitor

         *            the visitor to apply to each value.

         * @param dataQuery

         *            defines the properties of the data to visit

         * @exception BaseException

         *                if there is an error while performing the visit

         */

        public void accept(Visitor visitor, DataQuery dataQuery)

                        throws BaseException;

        /**

         * Loads all available data and notifies the observer for each loaded block of data.

         *

         * @param observer

         *            to be notified for each block of data loaded

         * @throws DataException

         *             if there is any error while loading the data

         */

        void getDataSet(Observer observer) throws DataException;

        /**

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

         * restrictions of the DataQuery. Data loading is performed by calling the

         * Observer, once each data block is loaded.

         *

         * @param dataQuery

         *            defines the properties of the requested data

         * @param observer

         *            to be notified for each block of data loaded

         * @throws DataException

         *             if there is any error while loading the data

         */

        void getDataSet(DataQuery dataQuery, Observer observer) throws DataException;

        /**

         * Returns the selected set of data

         *

         * @return DataSet

         */

        public DataSet getSelection() throws DataException;

        /**

         * Sets the current data selection with the given data set.

         *

         * @param DataSet

         *            selection

         * @throws DataException

         */

        public void setSelection(DataSet selection) throws DataException;

        /**

         * Creates a new selection.

         *

         * @return DataSet that contains the selection

         *

         * @throws DataException

         */

        public DataSet createSelection() throws DataException;

        /**

         * Returns an iterator over this store children

         *

         * @return Iterator over this DataStore children

         */

        public Iterator getChildren();

        /**

         * Returns the DataServerExplorer to which this DataStore belongs, if there

         * is any.

         * 

         * @return DataServerExplorer to which this DataStore belongs, or

         *         <code>null</code> if this was not accessed through any

         *         DataServerExplorer.

         * 

         * @throws DataException

         * @throws ValidateDataParametersException

         */

        public DataServerExplorer getExplorer() throws DataException,

                        ValidateDataParametersException;

        /**

         * Returns a new instance of a {@link DataQuery}.

         *

         * @return new {@link DataQuery} instance.

         *

         * @throws DataException

         */

        public DataQuery createQuery();

}