    001    //$HeadURL: https://svn.wald.intevation.org/svn/deegree/base/branches/2.4_testing/src/org/deegree/model/filterencoding/Literal.java $
    002    /*----------------------------------------------------------------------------
    003     This file is part of deegree, http://deegree.org/
    004     Copyright (C) 2001-2009 by:
    005       Department of Geography, University of Bonn
    006     and
    007       lat/lon GmbH
    008
    009     This library is free software; you can redistribute it and/or modify it under
    010     the terms of the GNU Lesser General Public License as published by the Free
    011     Software Foundation; either version 2.1 of the License, or (at your option)
    012     any later version.
    013     This library is distributed in the hope that it will be useful, but WITHOUT
    014     ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
    015     FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License for more
    016     details.
    017     You should have received a copy of the GNU Lesser General Public License
    018     along with this library; if not, write to the Free Software Foundation, Inc.,
    019     59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
    020
    021     Contact information:
    022
    023     lat/lon GmbH
    024     Aennchenstr. 19, 53177 Bonn
    025     Germany
    026     http://lat-lon.de/
    027
    028     Department of Geography, University of Bonn
    029     Prof. Dr. Klaus Greve
    030     Postfach 1147, 53001 Bonn
    031     Germany
    032     http://www.geographie.uni-bonn.de/deegree/
    033
    034     e-mail: info@deegree.org
    035    ----------------------------------------------------------------------------*/
    036    package org.deegree.model.filterencoding;
    037
    038    import org.deegree.framework.xml.XMLTools;
    039    import org.deegree.model.feature.Feature;
    040    import org.w3c.dom.Element;
    041
    042    /**
    043     * Encapsulates the information of a <Literal>element as defined in the FeatureId DTD.
    044     *
    045     * @author Markus Schneider
    046     * @version 07.08.2002
    047     */
    048    public class Literal extends Expression {
    049
    050        /** The literal's value. */
    051        private String value;
    052
    053        /**
    054         * Constructs a new Literal.
    055         *
    056         * @param value
    057         */
    058        public Literal( String value ) {
    059            id = ExpressionDefines.LITERAL;
    060            this.value = value;
    061        }
    062
    063        /**
    064         * Given a DOM-fragment, a corresponding Expression-object is built. This method recursively
    065         * calls other buildFromDOM () - methods to validate the structure of the DOM-fragment.
    066         *
    067         * @param element
    068         *
    069         * @throws FilterConstructionException
    070         *             if the structure of the DOM-fragment is invalid
    071         */
    072        public static Expression buildFromDOM( Element element )
    073                                throws FilterConstructionException {
    074
    075            // check if root element's name equals 'Literal'
    076            if ( !element.getLocalName().equals( "Literal" ) ) {
    077                throw new FilterConstructionException( "Name of element does not equal 'Literal'!" );
    078            }
    079
    080            return new Literal( XMLTools.getStringValue( element ) );
    081        }
    082
    083        /**
    084         * Returns the literal's value (as String).
    085         *
    086         * @return the literal's value (as String).
    087         */
    088        public String getValue() {
    089            return value;
    090        }
    091
    092        /**
    093         * @see org.deegree.model.filterencoding.Literal#getValue()
    094         * @param value
    095         */
    096        public void setValue( String value ) {
    097            this.value = value;
    098        }
    099
    100        /**
    101         * Produces an indented XML representation of this object.
    102         *
    103         * @return XML representation of this object.
    104         */
    105        @Override
    106        public StringBuffer toXML() {
    107            StringBuffer sb = new StringBuffer( 200 );
    108            // use CDATA section because content may not allowed within
    109            // simple XML elements
    110            sb.append( "<ogc:Literal><![CDATA[" ).append( value ).append( "]]></ogc:Literal>" );
    111            return sb;
    112        }
    113
    114        /**
    115         * Returns the <code>Literal</code>'s value (to be used in the evaluation of a complexer
    116         * <code>Expression</code>). If the value appears to be numerical, a <code>Double</code> is
    117         * returned, else a <code>String</code>. TODO: Improve datatype handling.
    118         *
    119         * @param feature
    120         *            that determines the values of <code>PropertyNames</code> in the expression (no
    121         *            use here)
    122         * @return the resulting value
    123         */
    124        @Override
    125        public Object evaluate( Feature feature ) {
    126            try {
    127                return new Double( value );
    128            } catch ( NumberFormatException e ) {
    129                // and then eat it
    130            }
    131            return value;
    132        }
    133    }