    001// Copyright 2011 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.tree;
    016
    017/**
    018 * Tracks which <em>leaf</em> nodes of a {@link TreeModel} are currently selected. The {@linkplain DefaultTreeSelectionModel default
    019 * implementation} simply stores a set of {@linkplain TreeNode#getId() unique node
    020 * ids} to identify selected nodes. The selection model is updated whenever the user clicks on the label for a leaf node.
    021 * <p/>
    022 * In the future, new methods may be added that will support selection of folders as well as leafs, and define the rules for
    023 * how selections and de-selections propagate down to children or up to parents.
    024 *
    025 * @param <T> type of node
    026 * @see org.apache.tapestry5.corelib.components.Tree
    027 * @since 5.3
    028 */
    029public interface TreeSelectionModel<T>
    030{
    031
    032    /**
    033     * Returns {@code true}, if the given node is selected.
    034     *
    035     * @param node node to check
    036     */
    037    boolean isSelected(TreeNode<T> node);
    038
    039    /**
    040     * Selects a node.
    041     *
    042     * @param node node to select
    043     */
    044    void select(TreeNode<T> node);
    045
    046    /**
    047     * Unselects a node.
    048     *
    049     * @param node node to unselect
    050     */
    051    void unselect(TreeNode<T> node);
    052
    053    /**
    054     * Clears the selection.
    055     */
    056    void clear();
    057}