/*---------------- FILE HEADER ------------------------------------------
This file is part of deegree.
Copyright (C) 2001-2006 by:
EXSE, Department of Geography, University of Bonn
http://www.giub.uni-bonn.de/deegree/
lat/lon GmbH
http://www.lat-lon.de
This library is free software; you can redistribute it and/or
modify it under the terms of the GNU Lesser General Public
License as published by the Free Software Foundation; either
version 2.1 of the License, or (at your option) any later version.
This library 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
Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public
License along with this library; if not, write to the Free Software
Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
Contact:
Andreas Poth
lat/lon GmbH
Aennchenstr. 19
53115 Bonn
Germany
E-Mail: poth@lat-lon.de
Prof. Dr. Klaus Greve
Department of Geography
University of Bonn
Meckenheimer Allee 166
53115 Bonn
Germany
E-Mail: greve@giub.uni-bonn.de
---------------------------------------------------------------------------*/
package org.deegree.model.filterencoding;
import org.deegree.framework.xml.XMLTools;
import org.deegree.model.feature.Feature;
import org.w3c.dom.Element;
/**
* Encapsulates the information of a <Literal>element as defined in the
* FeatureId DTD.
*
* @author Markus Schneider
* @version 07.08.2002
*/
public class Literal extends Expression {
/** The literal's value. */
private String value;
/** Constructs a new Literal. */
public Literal(String value) {
id = ExpressionDefines.LITERAL;
this.value = value;
}
/**
* Given a DOM-fragment, a corresponding Expression-object is built. This
* method recursively calls other buildFromDOM () - methods to validate the
* structure of the DOM-fragment.
*
* @throws FilterConstructionException
* if the structure of the DOM-fragment is invalid
*/
public static Expression buildFromDOM(Element element)
throws FilterConstructionException {
// check if root element's name equals 'Literal'
if (!element.getLocalName().equals("Literal"))
throw new FilterConstructionException(
"Name of element does not equal 'Literal'!");
return new Literal(XMLTools.getStringValue(element));
}
/**
* Returns the literal's value (as String).
*/
public String getValue() {
return value;
}
/**
* @see org.deegree.model.filterencoding.Literal#getValue()
*/
public void setValue(String value) {
this.value = value;
}
/** Produces an indented XML representation of this object. */
public StringBuffer toXML() {
StringBuffer sb = new StringBuffer(200);
sb.append("<ogc:Literal>").append(value).append("</ogc:Literal>");
return sb;
}
/**
* Returns the <tt>Literal</tt>'s value (to be used in the evaluation of
* a complexer <tt>Expression</tt>). If the value appears to be
* numerical, a <tt>Double</tt> is returned, else a <tt>String</tt>.
* TODO: Improve datatype handling.
*
* @param feature
* that determines the values of <tt>PropertyNames</tt> in the
* expression (no use here)
* @return the resulting value
*/
public Object evaluate(Feature feature) {
try {
return new Double(value);
} catch (NumberFormatException e) {
}
return value;
}
}/* ********************************************************************
Changes to this class. What the people have been up to:
$Log: Literal.java,v $
Revision 1.9 2006/07/12 14:46:14 poth
comment footer added
********************************************************************** */