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.simple;
016
017import org.apache.tapestry.IRender;
018import org.apache.tapestry.IRequestCycle;
019import org.apache.tapestry.contrib.table.model.ITableColumn;
020import org.apache.tapestry.contrib.table.model.ITableModelSource;
021import org.apache.tapestry.contrib.table.model.ITableRendererSource;
022import org.apache.tapestry.valid.RenderString;
023
024/**
025 * This is a simple implementation of 
026 * {@link org.apache.tapestry.contrib.table.model.ITableRendererSource} 
027 * that returns a standard renderer of a column value.
028 * 
029 * This implementation requires that the column passed is of type SimpleTableColumn
030 * 
031 * @see org.apache.tapestry.contrib.table.model.common.AbstractTableColumn
032 * @author mindbridge
033 * @since 2.3
034 */
035public class SimpleTableValueRendererSource implements ITableRendererSource
036{
037        private static final long serialVersionUID = 1L;
038        
039    /** 
040     *  The representation of null values. This is geared towards HTML, but will
041     *  work for some other *ML languages as well. In any case, changing the 
042     *  column's value renderer allows selecting fully custom rendering behaviour. 
043     **/ 
044    private static final String EMPTY_REPRESENTATION = " ";
045
046        /**
047         * @see org.apache.tapestry.contrib.table.model.ITableRendererSource#getRenderer(IRequestCycle, ITableModelSource, ITableColumn, Object)
048         */
049        public IRender getRenderer(
050                IRequestCycle objCycle,
051                ITableModelSource objSource,
052                ITableColumn objColumn,
053                Object objRow)
054        {
055                SimpleTableColumn objSimpleColumn = (SimpleTableColumn) objColumn;
056
057                Object objValue = objSimpleColumn.getColumnValue(objRow);
058                if (objValue == null)
059                        return new RenderString(EMPTY_REPRESENTATION, true);
060
061                return new RenderString(objValue.toString());
062        }
063
064}