    001    // Copyright 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.grid;
    016
    017    import java.util.List;
    018
    019    /**
    020     * Models the sorting applied to the a {@link org.apache.tapestry5.grid.GridDataSource}.
    021     */
    022    public interface GridSortModel
    023    {
    024        /**
    025         * Identifies how (or if) a column is sorted.
    026         *
    027         * @param columnId
    028         * @return the sort for the indicated column or {@link org.apache.tapestry5.grid.ColumnSort#UNSORTED} if the column
    029         *         is not used for sorting
    030         */
    031        ColumnSort getColumnSort(String columnId);
    032
    033        /**
    034         * Updates the column sort.  The receiver determines how to handle the sort request.
    035         *
    036         * @param columnId property id of column to sort on
    037         */
    038        void updateSort(String columnId);
    039
    040        /**
    041         * Returns a list of sort constraints, identifying which columns are sorted, and how.  May return an empty list (but
    042         * won't return null).
    043         *
    044         * @see org.apache.tapestry5.grid.GridDataSource#prepare(int, int, java.util.List)
    045         */
    046        List<SortConstraint> getSortConstraints();
    047
    048        void clear();
    049    }