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

import java.util.Iterator;

import java.util.NoSuchElementException;

import org.gvsig.fmap.dal.exceptions.DataEvaluatorException;

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

import org.gvsig.fmap.dal.feature.impl.DefaultFeature;

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

import org.gvsig.tools.evaluator.Evaluator;

import org.gvsig.tools.evaluator.EvaluatorException;

public class FilteredIterator extends DefaultIterator {

        protected boolean nextChecked;

        protected DefaultFeature current;

        protected Evaluator filter;

        protected FilteredIterator(DefaultFeatureSet featureSet) {

                super(featureSet);

                this.current = null;

                this.nextChecked = false;

                this.filter = featureSet.query.getFilter();

        }

        FilteredIterator(DefaultFeatureSet featureSet, long index)

                        throws DataException {

                super(featureSet);

                this.iterator = featureSet.provider.iterator();

                if (index > 0) {

                        this.skypto(index);

                }

                this.current = null;

                this.nextChecked = false;

                this.filter = featureSet.query.getFilter();

        }

        protected void skypto(long index) {

                // TODO: Comprobar si esta bien la condicion de n<=

                for (long n = 0; n <= index && this.hasNext(); n++, this.next()) {

                        ;

                }

        }

        protected void doNext() throws DataException {

                nextChecked = true;

                DefaultFeature feature;

                FeatureData data;

                while (this.getIterator().hasNext()) {

                        data = (FeatureData) this.getIterator().next();

                        if (isDeleted(data)) {

                                continue;

                        }

                        feature = this.createFeature(data);

                        if (this.match(feature)) {

                                this.current = feature;

                                return;

                        }

                }

                this.current = null;

        }

        protected Iterator getIterator() {

                return this.iterator;

        }

        public boolean hasNext() {

                fset.checkModified();

                if (nextChecked) {

                        return this.current != null;

                }

                try {

                        doNext();

                } catch( DataException e) {

                        NullPointerException ex = new NullPointerException();

                        ex.initCause(e);

                        throw ex;

                }

                return this.current != null;

        }

        public boolean match(DefaultFeature feature) throws DataException {

                try {

                        return ((Boolean) this.filter.evaluate(feature)).booleanValue();

                } catch (EvaluatorException e) {

                        throw new DataEvaluatorException(e);

                }

        }

        public Object next() {

                fset.checkModified();

                if (!nextChecked) {

                        hasNext();

                }

                if (this.current == null) {

                        throw new NoSuchElementException();

                }

                nextChecked = false;

                DefaultFeature feature = this.current;

                this.current = null;

                return feature;

        }

}