    001    // Copyright 2007, 2008 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.tapestry5.internal.grid;
    016
    017    import org.apache.tapestry5.grid.GridDataSource;
    018    import org.apache.tapestry5.grid.SortConstraint;
    019
    020    import java.util.List;
    021
    022    /**
    023     * An implementation of {@link org.apache.tapestry5.grid.GridDataSource} used when the value null is provided as the
    024     * source.
    025     */
    026    public class NullDataSource implements GridDataSource
    027    {
    028        public int getAvailableRows()
    029        {
    030            return 0;
    031        }
    032
    033        public Class getRowType()
    034        {
    035            return null;
    036        }
    037
    038        public void prepare(int startIndex, int endIndex, List<SortConstraint> sortConstraints)
    039        {
    040        }
    041
    042        public Object getRowValue(int index)
    043        {
    044            return null;
    045        }
    046
    047    }