Application: gvSIG desktop

/* gvSIG. Sistema de Informaci�n Geogr�fica de la Generalitat Valenciana

 *

 * Copyright (C) 2004 IVER T.I. and Generalitat Valenciana.

 *

 * 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 2

 * 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., 59 Temple Place - Suite 330, Boston, MA  02111-1307,USA.

 *

 * For more information, contact:

 *

 *  Generalitat Valenciana

 *   Conselleria d'Infraestructures i Transport

 *   Av. Blasco Ib��ez, 50

 *   46010 VALENCIA

 *   SPAIN

 *

 *      +34 963862235

 *   gvsig@gva.es

 *      www.gvsig.gva.es

 *

 *    or

 *

 *   IVER T.I. S.A

 *   Salamanca 50

 *   46005 Valencia

 *   Spain

 *

 *   +34 963163400

 *   dac@iver.es

 */

package org.gvsig.sldsupport.filterencoding;

import java.io.IOException;

import java.util.HashSet;

import java.util.Set;

import org.gvsig.sldsupport.exception.SLDReadException;

import org.xmlpull.v1.XmlPullParser;

import org.xmlpull.v1.XmlPullParserException;

/**

 * Implements the main functionalities to parse a comparison operator

 * of a Filter Encoding expression.<br>

 * 

 * A comparison operator is used to form expressions that evaluate the 

 * mathematical comparison between two arguments. If the arguments satisfy

 * the comparison then the expression evaluates to TRUE.Otherwise the 

 * expression evaluates to FALSE.

 *

 * @see http://www.opengeospatial.org/standards/filter

 * @author pepe vidal salvador - jose.vidal.salvador@iver.es

 */

public class FComparisonOperator  {

        String comparisonType;

        FExpression insideExpression;

        FExpression insideExpression2;

        Set <String> fieldNames = new HashSet <String>();

        boolean value = true;

        int hasIntervals = 0;

        protected String opExpressionStr ="";

        public void parse(XmlPullParser parser, String tag)

                        throws XmlPullParserException, IOException, SLDReadException {

                int currentTag;

                boolean end = false;

                this.comparisonType = tag;

                parser.require(XmlPullParser.START_TAG, null, tag);

                currentTag = parser.next();

                while (!end)

                {

                        switch(currentTag)

                        {

                        case XmlPullParser.START_TAG:

                                insideExpression =new FExpression();

                                insideExpression.parse(parser,currentTag,parser.getName());        

                                opExpressionStr += insideExpression.getExpressionStr();

                                opExpressionStr += FilterUtils.getSymbol4Expression("ogc:"+this.comparisonType) + " ";

                                fieldNames.addAll(insideExpression.getFieldNames());

                                currentTag = parser.nextTag();

                                insideExpression2 =new FExpression();

                                insideExpression2.parse(parser, currentTag,parser.getName());

                                opExpressionStr += insideExpression2.getExpressionStr();

                                fieldNames.addAll(insideExpression2.getFieldNames());

                                parser.nextTag();

                                if (insideExpression == null || insideExpression2 == null) {

                                        throw new SLDReadException(new Exception(

                                                        "Bad expressions in comparison operator."));

                                }

                        case XmlPullParser.END_TAG:

                                if (parser.getName().compareTo(tag) == 0)

                                        end = true;

                                break;

                        case XmlPullParser.TEXT:

                                break;

                        }

                        if (!end)

                                currentTag = parser.next();

                }

                parser.require(XmlPullParser.END_TAG, null, tag);

        }

        public String getComparisonType() { return comparisonType; }

        public void setComparisonType(String comparisonType) { this.comparisonType = comparisonType; }

        public boolean evaluate() { return value; }

        public Set<String> getFieldNames() { return fieldNames; }

        public int getHasIntervals() { return hasIntervals; }

        public FExpression getInsideExpression() { return insideExpression; }

        public FExpression getInsideExpression2() {return insideExpression2; }

        public String getOpExpressionStr() {return opExpressionStr;}

}