001 //$HeadURL: https://svn.wald.intevation.org/svn/deegree/base/branches/2.3_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 }