Application: gvSIG desktop

package org.gvsig.app.project.symboltables;

import java.util.Iterator;

import java.util.List;

import java.util.NoSuchElementException;

import org.gvsig.expressionevaluator.Expression;

import org.gvsig.expressionevaluator.ExpressionEvaluatorLocator;

import org.gvsig.expressionevaluator.ExpressionEvaluatorManager;

import org.gvsig.expressionevaluator.MutableSymbolTable;

import org.gvsig.expressionevaluator.SymbolTable;

import org.gvsig.fmap.dal.DALLocator;

import org.gvsig.fmap.dal.DataManager;

import org.gvsig.fmap.dal.expressionevaluator.FeatureSymbolTable;

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

import org.gvsig.tools.util.UnmodifiableBasicList;

import org.gvsig.tools.util.UnmodifiableBasicListToListAdapter;

/**

 *

 * @author jjdelcerro

 */

public class ListOfFeaturesWrapper implements UnmodifiableBasicList<Object> {

    private final List<Feature> features;

    private final FeatureSymbolTable featureSymbolTable;

    private final MutableSymbolTable symbolTable;

    private final Expression expression;

    public ListOfFeaturesWrapper(

            List<Feature> features, 

            SymbolTable symbolTable, 

            String expression

        ) {

        DataManager dataManager = DALLocator.getDataManager();

        ExpressionEvaluatorManager expManager = ExpressionEvaluatorLocator.getManager();

        this.features = features;

        this.featureSymbolTable = dataManager.createFeatureSymbolTable();

        this.symbolTable = this.featureSymbolTable.createParent();

        this.symbolTable.addSymbolTable(symbolTable);

        this.expression = expManager.createExpression();

        this.expression.setPhrase(expression);

    }

    private Object getValue(Feature feature) {

        this.featureSymbolTable.setFeature(feature);

        Object value = this.expression.execute(this.symbolTable);

        return value;

    }

    @Override

    public boolean isEmpty() {

        return this.features.isEmpty();

    }

    @Override

    public List<Object> toList() {

        List<Object> x = new UnmodifiableBasicListToListAdapter<>(this);

        return x;

    }

    @Override

    public Object get(int position) {

        return this.getValue(this.features.get(position));

    }

    @Override

    public int size() {

        return this.features.size();

    }

    @Override

    public Iterator<Object> iterator() {

        return new Itr();

    }

    private class Itr implements Iterator<Object> {

        int cursor;       // index of next element to return

        Itr() {}

        @Override

        public boolean hasNext() {

            return cursor != size();

        }

        @Override

        public Object next() {

            int i = cursor;

            if (i >= size())

                throw new NoSuchElementException();

            cursor = i + 1;

            return get(i);

        }

        @Override

        public void remove() {

            throw new UnsupportedOperationException("Not supported yet."); 

        }

    }

}