| gvSIG desktop 1

/* gvSIG. Geographic Information System of the Valencian Government

 *

 * Copyright (C) 2007-2008 Infrastructures and Transports Department

 * of the Valencian Government (CIT)

 *

 * 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 2

 * 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.

 *

 */

/*

 * AUTHORS (In addition to CIT):

 * 2008 {DiSiD Technologies}  {Create Parameter object to define FeatureCollections queries}

 */

package org.gvsig.fmap.dal.feature;

import org.gvsig.fmap.dal.DataQuery;

import org.gvsig.tools.evaluator.Evaluator;

import org.gvsig.tools.lang.Cloneable;

/**

 * Defines the properties of a collection of Features, as a result of a query

 * through a FeatureStore.

 * <p>

 * A FeatureQuery is always defined by a FeatureType, or by the list of

 * attribute names of the FeatureStore to return.

 * </p>

 * <p>

 * The filter allows to select Features whose properties have values with the

 * characteristics defined by the filter.

 * </p>

 * <p>

 * The order is used to set the order of the result FeatureCollection, based on

 * the values of the properties of the Features.

 * </p>

 * <p>

 * The scale parameter can be used by the FeatureStore as a hint about the

 * quality or resolution of the data needed to view or operate with the data

 * returned. As an example, the FeatureStore may use the scale to return only a

 * representative subset of the data, or maybe to return Features with less

 * detail, like a point or a line instead of a polygon.

 * </p>

 * <p>

 * If an implementation of FeatureStore is able to get other parameters to

 * customize the behavior of the getDataCollection methods, there is an option

 * to set more parameters through the setAttribute method.

 * </p>

 *

 * @author 2009- <a href="cordinyana@gvsig.org">C?sar Ordi?ana</a> - gvSIG team

 */

public interface FeatureQuery extends DataQuery, Cloneable {

        /**

         * Returns the names of the attributes to load from each {@link Feature}.

         *

         * @return the attribute names to load

         */

        String[] getAttributeNames();

        /**

         * Sets the names of the attributes to load from each {@link Feature}.

         *

         * @param attributeNames

         *            the attribute names to load

         */

        void setAttributeNames(String[] attributeNames);

        /**

         * Adds the name of an attribute that has to be used to load each

         * {@link Feature}.

         *

         * @param attributeName

         *             the attribute name to load

         */

        void addAttributeName(String attributeName);

        /**

         * Sets the {@link FeatureType} of the {@link Feature}s to load. It may be

         * used as an alternative way to set a subset of the list of attribute names

         * to load, by creating a sub-FeatureType.

         *

         * @param featureType

         *            the feature type of the data to load

         */

        void setFeatureType(FeatureType featureType);

        /**

         * Returns the {@link FeatureType} id of the {@link Feature}s to load.

         *

         * @return the {@link FeatureType} id of the {@link Feature}s to load

         */

        String getFeatureTypeId();

        /**

         * Sets the {@link FeatureType} id of the {@link Feature}s to load. This way

         * all {@link Feature} attributes will be loaded.

         *

         * @param featureTypeId

         *            the {@link FeatureType} id of the {@link Feature}s to load

         */

        void setFeatureTypeId(String featureTypeId);

        /**

         * Returns the filter to apply to the {@link Feature}s to load.

         *

         * @return the filter

         */

        Evaluator getFilter();

        /**

         * Sets the filter to apply to the {@link Feature}s to load.

         *

         * @param filter

         *            the filter to apply to the {@link Feature}s to load

         */

        void setFilter(Evaluator filter);

        /**

         * Adds a filter to apply to the {@link Feature}s to load. A query

         * can have more that one filter and all of them are applied when

         * the query is applied.

         *

         * @param filter

         *             a filter to apply to the {@link Feature}s to load

         */

        void addFilter(Evaluator filter);

        /**

         * Returns if a filter has been defined for the query.

         *

         * @return if a filter has been defined for the query

         */

        boolean hasFilter();

        /**

         * Returns the order of the {@link Feature}s to load.

         *

         * @return the order of the {@link Feature}s to load

         */

        FeatureQueryOrder getOrder();

        /**

         * Sets the order of the {@link Feature}s to load.

         *

         * @param order

         *            the order of the {@link Feature}s to load

         */

        void setOrder(FeatureQueryOrder order);

        /**

         * Returns if an order has been set for the elements returned by the query.

         *

         * @return if an order has been set for the elements returned by the query

         */

        boolean hasOrder();

        /**

         * @deprecated to be removed in gvSIG 2.0

         * @see #clone()

         */

        FeatureQuery getCopy();

        /**

         * Returns the maximum number of elements to return with this query.

         * <p>

         * <strong>NOTE:</strong> this value may be ignored by the underlying data

         * source, or only used as a hint, so don't rely on it being used, as you

         * may actually get more values than the limit.

         * </p>

         *

         * @return the maximum number of elements to return with this query

         */

        long getLimit();

        /**

         * Sets the maximum number of elements to return with this query.

         * <p>

         * <strong>NOTE:</strong> this value may be ignored by the underlying data

         * source, or only used as a hint, so don't rely on it being used, as you

         * may actually get more values than the limit.

         * </p>

         *

         * @param limit

         *            the maximum number of elements to return with this query

         */

        void setLimit(long limit);

        /**

         * Returns the load page size, as the number of elements to be retrieved in

         * block by the data source. This value is only used as a hint to the

         * underlying data source, as a way to tell how many Features may be read in

         * a block.

         *

         * @return the load page size

         */

        long getPageSize();

        /**

         * Sets the load page size, as the number of elements to be retrieved in

         * block by the data source. This value is only used as a hint to the

         * underlying data source, as a way to tell how many Features may be read in

         * a block.

         *

         * @param pageSize

         *            the load page size

         */

        void setPageSize(long pageSize);

}