Application: gvSIG desktop

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package org.gvsig.fmap.dal.feature.impl.featurereference;

import java.util.Collections;

import java.util.Iterator;

import java.util.logging.Level;

import java.util.logging.Logger;

import org.gvsig.expressionevaluator.ExpressionBuilder;

import org.gvsig.expressionevaluator.ExpressionUtils;

import org.gvsig.fmap.dal.DataServerExplorer_v2;

import org.gvsig.fmap.dal.SQLBuilder;

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

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

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

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

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

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

import org.gvsig.fmap.dal.feature.spi.FeatureReferenceProviderServices;

import org.gvsig.tools.util.ChainedIterator;

/**

 *

 * @author jjdelcerro

 */

public class FeatureReferenceIteratorToFeatureIterator implements Iterator<Feature> {

    private Iterator<FeatureReference> references;

    private Iterator<Feature> it;

    private final FeatureStore store;

    private int maxRecomendedSQLLength;

    private int count;

    private int maxcount;

    public FeatureReferenceIteratorToFeatureIterator(FeatureStore store, Iterator<FeatureReference> references) {

        this.count = 0;

        this.store = store;

        this.references = references;

        this.it = null;

        try {

            SQLBuilder sqlbuilder = ((DataServerExplorer_v2)this.store.getExplorer()).createSQLBuilder();

            this.maxRecomendedSQLLength = sqlbuilder.getMaxRecomendedSQLLength() - 200;

        } catch (Exception ex) {

            this.maxRecomendedSQLLength = SQLBuilder.DEFAULT_RECOMENDED_SQL_LENGTH - 200;

        }

        this.maxcount = this.maxRecomendedSQLLength / 50; // Cada getReferenceFilter son aprox 50

    }

    @Override

    public boolean hasNext() {

        if (this.it != null) {

            if (this.it.hasNext()) {

                return true;

            }

        }

        this.it = this.getNextPage();

        return this.it.hasNext();

    }

    @Override

    public Feature next() {

        if (this.it != null) {

            return this.it.next();

        }

        this.it = this.getNextPage();

        return this.it.next();

    }

    private Iterator<Feature> getNextPage() {

        try {

            ExpressionBuilder builder = ExpressionUtils.createExpressionBuilder();

            int count = 0;

            while (this.references.hasNext()) {

                FeatureReferenceProviderServices reference = (FeatureReferenceProviderServices) references.next();

                this.count++;

                if( reference==null ) {

                    continue;

                }

                if( reference instanceof FeatureReferencePK ) {

                    builder.or(this.getReferenceFilter(reference));

                    count++;

                    if (!references.hasNext() || count > this.maxcount) { // filter.length() >  this.maxRecomendedSQLLength) { 

                        String filter = builder.build(); // Ojo, mover arriba del if es lentisimo ??

                        if (filter != null) {

                            FeatureSet set = this.store.getFeatureSet(filter);

                            return set.fastIterator(); // Disposes?

                        }

                    }

                } else {

                    String filter = builder.build();

                    Feature feature = reference.getFeature();

                    if (filter != null) {

                        FeatureSet set = this.store.getFeatureSet(filter);

                        if( feature == null ) {

                            return set.fastIterator();

                        }

                        return new ChainedIterator<>(

                                set.fastIterator(),

                                Collections.singleton(feature).iterator()

                        );

                    } else {

                        if( feature!=null ) {

                            return Collections.singleton(feature).iterator();

                        }

                    }

                }

            }

            return Collections.EMPTY_LIST.iterator();

        } catch (DataException ex) {

            throw new RuntimeException("Can't get next page of iterator", ex);

        }

    }

    private ExpressionBuilder.Value getReferenceFilter(FeatureReferenceProviderServices reference) {

        ExpressionBuilder builder = ExpressionUtils.createExpressionBuilder();

        String[] primaryKeys = reference.getKeyNames();

        for (String name : primaryKeys) {

            Object value = reference.getKeyValue(name);

            if (value == null) {

                builder.and(builder.is_null(builder.column(name)));

            } else {

                builder.and(

                        builder.eq(

                                builder.column(name),

                                builder.constant(value)

                        )

                );

            }

        }

        return builder.value();

    }

}