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}