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.simple;
016    
017    import org.apache.tapestry.IRender;
018    import org.apache.tapestry.IRequestCycle;
019    import org.apache.tapestry.contrib.table.model.ITableColumn;
020    import org.apache.tapestry.contrib.table.model.ITableModelSource;
021    import org.apache.tapestry.contrib.table.model.ITableRendererSource;
022    import org.apache.tapestry.valid.RenderString;
023    
024    /**
025     * This is a simple implementation of
026     * {@link org.apache.tapestry.contrib.table.model.ITableRendererSource} that
027     * returns a standard renderer of a column value. This implementation requires
028     * that the column passed is of type SimpleTableColumn
029     * 
030     * @see org.apache.tapestry.contrib.table.model.common.AbstractTableColumn
031     * @author mindbridge
032     * @since 2.3
033     */
034    public class SimpleTableValueRendererSource implements ITableRendererSource
035    {
036        private static final long serialVersionUID = 1L;
037    
038        /**
039         * The representation of null values. This is geared towards HTML, but will
040         * work for some other *ML languages as well. In any case, changing the
041         * column's value renderer allows selecting fully custom rendering
042         * behaviour.
043         */
044        private static final String EMPTY_REPRESENTATION = " ";
045    
046        /**
047         * @see org.apache.tapestry.contrib.table.model.ITableRendererSource#getRenderer(IRequestCycle,
048         *      ITableModelSource, ITableColumn, Object)
049         */
050        public IRender getRenderer(IRequestCycle objCycle,
051                ITableModelSource objSource, ITableColumn objColumn, Object objRow)
052        {
053            SimpleTableColumn objSimpleColumn = (SimpleTableColumn) objColumn;
054    
055            Object objValue = objSimpleColumn.getColumnValue(objRow);
056            if (objValue == null)
057                return new RenderString(EMPTY_REPRESENTATION, true);
058    
059            return new RenderString(objValue.toString());
060        }
061    
062    }