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
015package org.apache.tapestry.contrib.table.model.ognl;
016
017import org.apache.commons.logging.Log;
018import org.apache.commons.logging.LogFactory;
019import org.apache.tapestry.contrib.table.model.ITableColumn;
020import org.apache.tapestry.contrib.table.model.simple.ITableColumnEvaluator;
021import org.apache.tapestry.services.ExpressionEvaluator;
022
023/**
024 * @author mindbridge
025 */
026public 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}