Application: gvSIG desktop

/**

 * gvSIG. Desktop Geographic Information System.

 *

 * Copyright (C) 2007-2020 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.expressionevaluator.impl.function.dataaccess;

import java.util.Objects;

import org.apache.commons.lang3.Range;

import org.gvsig.expressionevaluator.Codes;

import org.gvsig.expressionevaluator.ExpressionRuntimeException;

import org.gvsig.expressionevaluator.Interpreter;

import org.gvsig.expressionevaluator.impl.DALFunctions;

import org.gvsig.expressionevaluator.spi.AbstractFunction;

import org.gvsig.fmap.dal.DALLocator;

import org.gvsig.fmap.dal.DataManager;

import static org.gvsig.fmap.dal.DataManager.FUNCTION_SELECT_COUNT;

import org.gvsig.fmap.dal.DataStore;

import org.gvsig.fmap.dal.feature.FeatureQuery;

import org.gvsig.fmap.dal.feature.FeatureSet;

import org.gvsig.fmap.dal.feature.FeatureStore;

import org.gvsig.tools.dispose.DisposeUtils;

/**

 *

 * @author jjdelcerro

 */

@SuppressWarnings("UseSpecificCatch")

public class SelectCountFunction extends AbstractFunction {

  public SelectCountFunction() {

    super(DALFunctions.GROUP_DATA_ACCESS,

            FUNCTION_SELECT_COUNT,

            Range.between(1,2),

            "Returns the number of features of the table by applying the filter indicated.\n" +

                    "The syntax is:\n\n"+

                    "SELECT * FROM table WHERE boolean_expression;\n\n"+

                    "Indicate a filter expression with WHERE is optional.\n"+

                    "The SELECT statement must always end with a semicolon.",

            "SELECT COUNT(*) FROM {{table}} WHERE filter ;",

            new String[]{

              "table - Name of the table",

              "filter - boolean expression with the filter to apply",

            },

            "Long",

            false

    );

  }

  @Override

  public boolean isHidden() {

    return false;

  }

  @Override

  public boolean allowConstantFolding() {

    return false;

  }

  @Override

  public boolean useArgumentsInsteadObjects() {

    return true;

  }

  @Override

  public Object call(Interpreter interpreter, Object[] args) throws Exception {

    throw new UnsupportedOperationException();

  }

  @Override

  public Object call(Interpreter interpreter, Codes args) throws Exception {

    String storeName =  (String) getObject(interpreter, args, 0);

    String where = Objects.toString(args.get(1),null);

    FeatureStore featureStore = null;

    FeatureSet set = null;

    try {

      DataStore store = this.getStore(storeName);

      if (store == null ) {

        throw new ExpressionRuntimeException("Cant locate the store '" + storeName + "' in function '" + FUNCTION_SELECT_COUNT + "'.");

      }

      if (!(store instanceof FeatureStore)) {

        throw new ExpressionRuntimeException("The store'" + storeName + "' is not valid for function '" + FUNCTION_SELECT_COUNT + "', a FeatureStore is required.");

      }

      featureStore = (FeatureStore) store;

      if (where == null ) {

        set = featureStore.getFeatureSet();

      } else {

        FeatureQuery query = featureStore.createFeatureQuery();

        query.addFilter(where);

        query.retrievesAllAttributes();

        set = featureStore.getFeatureSet(query);

      }

      return set.getSize();

    } catch (ExpressionRuntimeException ex) {

      throw ex;

    } catch (Exception ex) {

      throw new ExpressionRuntimeException("Problems calling '" + FUNCTION_SELECT_COUNT + "' function", ex);

    } finally {

      DisposeUtils.disposeQuietly(set);

      DisposeUtils.disposeQuietly(featureStore);

    }

  }

  protected DataStore getStore(String storeName) {

    DataManager dataManager = DALLocator.getDataManager();

    DataStore store = dataManager.getStoresRepository().getStore(storeName);

    return store;

  }

}