    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
    015package org.apache.tapestry5.grid;
    016
    017import java.util.List;
    018
    019/**
    020 * Models the sorting applied to the a {@link org.apache.tapestry5.grid.GridDataSource}.
    021 */
    022public 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}