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} 
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     */
035    public 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    }