001    /*
002     * 
003     * $Revision: 13085 $ $Date: 2008-02-06 18:27:24 +0100 (Mi, 06 Feb 2008) $
004     *
005     * This file is part of ***  M y C o R e  ***
006     * See http://www.mycore.de/ for details.
007     *
008     * This program is free software; you can use it, redistribute it
009     * and / or modify it under the terms of the GNU General Public License
010     * (GPL) as published by the Free Software Foundation; either version 2
011     * of the License or (at your option) any later version.
012     *
013     * This program is distributed in the hope that it will be useful, but
014     * WITHOUT ANY WARRANTY; without even the implied warranty of
015     * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
016     * GNU General Public License for more details.
017     *
018     * You should have received a copy of the GNU General Public License
019     * along with this program, in a file called gpl.txt or license.txt.
020     * If not, write to the Free Software Foundation Inc.,
021     * 59 Temple Place - Suite 330, Boston, MA  02111-1307 USA
022     */
023    
024    package org.mycore.services.fieldquery;
025    
026    import org.jdom.Element;
027    import org.mycore.parsers.bool.MCRCondition;
028    import org.mycore.parsers.bool.MCRConditionVisitor;
029    import org.mycore.parsers.bool.MCRParseException;
030    
031    /**
032     * Represents a simple query condition, which consists of a search field,
033     * a value and a comparison operator.
034     * 
035     * @author Frank Lützenkirchen
036     */
037    public class MCRQueryCondition extends MCRFieldValue implements MCRCondition {
038        
039        /** The comparison operator used in this condition */
040        private String operator;
041    
042        /** Creates a new simple query condition */
043        public MCRQueryCondition(MCRFieldDef field, String operator, String value) {
044            super( field, value );
045            
046            if (!MCRFieldType.isValidOperatorForType(field.getDataType(), operator))
047                throw new MCRParseException("Search operator <" + operator + "> not allowed for field <" + field.getName() + ">");
048            
049            this.operator = operator;
050        }
051    
052        /** Returns the comparison operator used in this condition */
053        public String getOperator() {
054            return operator;
055        }
056    
057        public String toString() {
058            return getField().getName() + " " + operator + " \"" + getValue() + "\"";
059        }
060    
061        public Element toXML() {
062            Element condition = new Element("condition");
063            condition.setAttribute("field", getField().getName());
064            condition.setAttribute("operator", operator);
065            condition.setAttribute("value", getValue());
066    
067            return condition;
068        }
069    
070        public Element info() {
071            return toXML();
072        }
073    
074        public void accept(MCRConditionVisitor visitor) {
075            visitor.visitQuery(this);
076        }
077    
078        public boolean evaluate(Object o) {
079            return false;
080        }
081    }