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.spi;

import java.util.Iterator;

import java.util.Objects;

import org.apache.commons.lang3.builder.ToStringBuilder;

import org.apache.commons.lang3.mutable.MutableObject;

import org.gvsig.expressionevaluator.Code;

import org.gvsig.expressionevaluator.Expression;

import org.gvsig.expressionevaluator.ExpressionEvaluatorLocator;

import org.gvsig.expressionevaluator.ExpressionEvaluatorManager;

import org.gvsig.expressionevaluator.Interpreter;

import org.gvsig.expressionevaluator.MutableSymbolTable;

import org.gvsig.expressionevaluator.SymbolTable;

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

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

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

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.dispose.impl.AbstractDisposable;

import org.gvsig.tools.exception.BaseException;

import org.gvsig.tools.visitor.VisitCanceledException;

import org.gvsig.tools.visitor.Visitor;

import org.slf4j.Logger;

import org.slf4j.LoggerFactory;

/**

 * Base implementation for {@link FeatureSetProvider}s, adding some utility

 * methods.

 * 

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

 */

public abstract class AbstractFeatureSetProvider extends AbstractDisposable

                implements FeatureSetProvider {

        protected static final Logger LOGGER = LoggerFactory.getLogger(AbstractFeatureSetProvider.class);

        private final AbstractFeatureStoreProvider store;

        private final FeatureQuery query;

        private final FeatureType providerFeatureType;

        private final FeatureType storeFeatureType;

        /**

         * Creates a new {@link FeatureSetProvider}.

         * 

         * @param store

         *            the underlying {@link FeatureStoreProvider} to get the data

         *            from

         * @param query

         *            used to create the {@link FeatureSetProvider}

         * @param providerFeatureType

         *            the type of feature to get

         */

        public AbstractFeatureSetProvider(AbstractFeatureStoreProvider store,

                        FeatureQuery query, FeatureType providerFeatureType, FeatureType storeFeatureType) {

                this.store = store;

                this.query = query;

                this.providerFeatureType = providerFeatureType;

                this.storeFeatureType = storeFeatureType;

        }

        public AbstractFeatureSetProvider(AbstractFeatureStoreProvider store,

                        FeatureQuery query, FeatureType providerFeatureType) {

            this(store, query, providerFeatureType, null);

        }

        /**

         * Return the {@link AbstractFeatureStoreProvider}.

         * 

         * @return the store

         */

        protected AbstractFeatureStoreProvider getStore() {

                return store;

        }

        /**

         * Returns the {@link FeatureQuery} used to create this set.

         * 

         * @return the query

         */

        protected FeatureQuery getQuery() {

                return query;

        }

        /**

         * Returns the type of features from provider to load.

         * 

         * @return the providerFeatureType

         */

        protected FeatureType getProviderFeatureType() {

                return providerFeatureType;

        }

        /**

         * Returns the type of features from store to load.

         * 

         * @return the storeFeatureType

         */

        protected FeatureType getStoreFeatureType() {

                return storeFeatureType;

        }

        /**

         * Returns the type of features from provider to load.

         * 

         * @return the providerFeatureType

         * @deprecated use getProviderFeatureType

         */        

        protected FeatureType getFeatureType() {

                return providerFeatureType;

        }

        @Override

        public final DisposableIterator fastIterator() throws DataException {

                return fastIterator(0);

        }

        public final DisposableIterator fastIterator(long index)

                        throws DataException {

                return createFastIterator(index);

        }

    @Override

    public final DisposableIterator fastIterator(long index, long elements) throws DataException {

                return createFastIterator(index, elements);

        }

    @Override

        public final DisposableIterator iterator() throws DataException {

                return iterator(0);

        }

        public final DisposableIterator iterator(long index) throws DataException {

                return createIterator(index);

        }

    @Override

        public final DisposableIterator iterator(long index, long elements) throws DataException {

                return createIterator(index, elements);

        }

        /**

         * Creates a new {@link Iterator}, begginning at the specified data index.

         * 

         * @param index

         *            the first element position to be returned by the

         *            {@link Iterator}

         * @return a new {@link Iterator}

         * @throws DataException

         *             if there is an error creating the {@link Iterator}

         */

        protected abstract AbstractFeatureProviderIterator createIterator(long index)

                        throws DataException;

        protected AbstractFeatureProviderIterator createIterator(long index, long elements)

                        throws DataException {

            return createIterator(index);

    }

    /**

         * Creates a new fast {@link Iterator}, begginning at the specified data

         * index. By fast this means the object instances of data (

         * {@link FeatureProvider}) may be reused between the

         * {@link Iterator#next()} method invocations.

         * 

         * @param index

         *            the first element position to be returned by the

         *            {@link Iterator}

         * @return a new {@link Iterator}

         * @throws DataException

         *             if there is an error creating the {@link Iterator}

         */

        protected abstract AbstractFeatureProviderIterator createFastIterator(

                        long index) throws DataException;

        protected AbstractFeatureProviderIterator createFastIterator(

                        long index, long elements) throws DataException {

            return createFastIterator(index);

        }

    @Override

    public String toString() {

        try {

            ToStringBuilder builder = new ToStringBuilder(this);

            builder.append("store", this.store, true);

            builder.append("query", this.query, true);

            return builder.toString();

        } catch (Exception e) {

            return super.toString();

        }

    }

    protected SpatialIndex getSpatialIndex(String name) {

        return null;

    }

    @SuppressWarnings("Convert2Lambda")

    protected Iterator createSpatialIterator(FeatureType featureType, FeatureQuery query) {

        if( featureType==null || query == null || query.getFilter()==null) {

            return null;

        }

        ExpressionEvaluatorManager expmanager = ExpressionEvaluatorLocator.getExpressionEvaluatorManager();

        Code filterCode = null;

        try {

            SymbolTable filterSymbolTable = null;

            Expression filterExp = query.getExpressionFilter();               

            if( filterExp == null ) {

                String sql = query.getFilter().getSQL();

                if( sql == null ) {

                    return null;

                }

                filterCode = expmanager.compile(sql);

            } else {

                filterCode = filterExp.getCode();

                filterSymbolTable = filterExp.getSymbolTable();

            }

            MutableObject<Code> spatialQuery = new MutableObject<>();

            MutableObject<SpatialIndex> spatialIndex = new MutableObject<>();

            try {

                filterCode.accept(new Visitor() {

                    @Override

                    public void visit(Object obj) throws VisitCanceledException, BaseException {

                        SpatialIndex spaIndex = null;

                        if (Code.isFunction((Code) obj, "NOT") && spatialIndex.getValue() == null) {

                            Code isCode = ((Code.Callable)obj).parameters().get(0);

                            if (Code.isFunction(isCode, "IS")) {

                                Code p1 = ((Code.Callable)isCode).parameters().get(0);

                                Code p2 = ((Code.Callable)isCode).parameters().get(1);

                                if (p1.code() == Code.IDENTIFIER && p2.code()==Code.CONSTANT && ((Code.Constant)p2).value()==null) {

                                    spaIndex = getSpatialIndex(((Code.Identifier) p1).name());

                                    if(spaIndex != null) {

                                        spatialIndex.setValue(spaIndex);

                                    }

                                }

                            }

                        } else if (Code.isFunction((Code) obj, "ST_INTERSECTS")

                            || Code.isFunction((Code) obj, "ST_CONTAINS")

                            || Code.isFunction((Code) obj, "&&")) {

                            Code.Callable intersects = (Code.Callable) obj;

                            Code p1 = intersects.parameters().get(0);

                            Code p2 = intersects.parameters().get(1);

                            Code sq = null;

                            if (p1.code() == Code.IDENTIFIER) {

                                spaIndex = getSpatialIndex(((Code.Identifier) p1).name());

                                if(spaIndex != null) {

                                    sq = p2;

                                }

                            } else if (p2.code() == Code.IDENTIFIER) {

                                spaIndex = getSpatialIndex(((Code.Identifier) p2).name());

                                if(spaIndex != null) {

                                    sq = p1;

                                }

                            }

                            if (sq != null) {

                                spatialIndex.setValue(spaIndex);

                                spatialQuery.setValue(sq);

                                throw new VisitCanceledException();

                            }

                        }

                    }

                });

            } catch(VisitCanceledException ex) {

            }

            if( spatialIndex.getValue() != null && spatialQuery.getValue()!=null ) {

                Interpreter interpreter = expmanager.createInterpreter();

                MutableSymbolTable symbolTable;

                if( filterSymbolTable instanceof MutableSymbolTable ) {

                    interpreter.setSymbolTable(filterSymbolTable);

                } else {

                    symbolTable = expmanager.createSymbolTable();

                    if( filterSymbolTable != null ) {

                        symbolTable.addSymbolTable(filterSymbolTable);

                    }

                    interpreter.setSymbolTable(symbolTable);

                }

                Envelope envelope = null;

                Object value = interpreter.runCode(spatialQuery.getValue());

                if( value instanceof Geometry ) {

                    envelope = ((Geometry)value).getEnvelope();

                } else if( value instanceof Envelope ) {

                    envelope = (Envelope) value;

                }

                if( envelope!=null ) {

                    return spatialIndex.getValue().query(envelope, Long.MAX_VALUE);

                }

            } else if( spatialIndex.getValue() != null) {

                return spatialIndex.getValue().queryAll();

            }

        } catch (Exception ex) {

            LOGGER.warn("Can't use spatial index for query '"+Objects.toString(filterCode)+"'.",ex);

        }

        return null;

    }

}