001    // Copyright 2004, 2005 The Apache Software Foundation
002    //
003    // Licensed under the Apache License, Version 2.0 (the "License");
004    // you may not use this file except in compliance with the License.
005    // You may obtain a copy of the License at
006    //
007    //     http://www.apache.org/licenses/LICENSE-2.0
008    //
009    // Unless required by applicable law or agreed to in writing, software
010    // distributed under the License is distributed on an "AS IS" BASIS,
011    // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
012    // See the License for the specific language governing permissions and
013    // limitations under the License.
014    
015    package org.apache.tapestry.contrib.table.model.ognl;
016    
017    import org.apache.commons.logging.Log;
018    import org.apache.commons.logging.LogFactory;
019    import org.apache.tapestry.contrib.table.model.ITableColumn;
020    import org.apache.tapestry.contrib.table.model.simple.ITableColumnEvaluator;
021    import org.apache.tapestry.services.ExpressionEvaluator;
022    
023    /**
024     * @author mindbridge
025     */
026    public class OgnlTableColumnEvaluator implements ITableColumnEvaluator
027    {
028            private static final long serialVersionUID = 1L;
029            
030        /** @since 4.0 */
031    
032        private ExpressionEvaluator _expressionEvaluator;
033    
034        private static final Log LOG = LogFactory.getLog(OgnlTableColumnEvaluator.class);
035    
036        private String m_strExpression;
037    
038        public OgnlTableColumnEvaluator(String strExpression, ExpressionEvaluator expressionEvaluator)
039        {
040            m_strExpression = strExpression;
041            _expressionEvaluator = expressionEvaluator;
042        }
043    
044        /**
045         * @see org.apache.tapestry.contrib.table.model.simple.ITableColumnEvaluator#getColumnValue(ITableColumn,
046         *      Object)
047         */
048        public synchronized Object getColumnValue(ITableColumn objColumn, Object objRow)
049        {
050            // If no expression is given, then this is a dummy column. Return something.
051            if (m_strExpression == null || m_strExpression.equals(""))
052                return "";
053    
054            try
055            {
056                return _expressionEvaluator.read(objRow, m_strExpression);
057            }
058            catch (Exception e)
059            {
060                LOG.error("Cannot use column expression '" + m_strExpression + "' in row", e);
061                return "";
062            }
063        }
064    }