Java tutorial
/* * Copyright 2000-2018 Vaadin Ltd. * * Licensed under the Apache License, Version 2.0 (the "License"); you may not * use this file except in compliance with the License. You may obtain a copy of * the License at * * http://www.apache.org/licenses/LICENSE-2.0 * * Unless required by applicable law or agreed to in writing, software * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the * License for the specific language governing permissions and limitations under * the License. */ package com.vaadin.data.provider; import java.util.Comparator; import java.util.List; import java.util.Optional; /** * Immutable hierarchical query object used to request data from a backend. * Contains the parent node, index limits, sorting and filtering information. * * @param <T> * bean type * @param <F> * filter type * * @since 8.1 */ public class HierarchicalQuery<T, F> extends Query<T, F> { private final T parent; /** * Constructs a new hierarchical query object with given filter and parent * node. * * @param filter * filtering for fetching; can be <code>null</code> * @param parent * the hierarchical parent object, <code>null</code> * corresponding to the root node */ public HierarchicalQuery(F filter, T parent) { super(filter); this.parent = parent; } /** * Constructs a new hierarchical query object with given offset, limit, * sorting and filtering. * * @param offset * first index to fetch * @param limit * fetched item count * @param sortOrders * sorting order for fetching; used for sorting backends * @param inMemorySorting * comparator for sorting in-memory data * @param filter * filtering for fetching; can be <code>null</code> * @param parent * the hierarchical parent object, <code>null</code> * corresponding to the root node */ public HierarchicalQuery(int offset, int limit, List<QuerySortOrder> sortOrders, Comparator<T> inMemorySorting, F filter, T parent) { super(offset, limit, sortOrders, inMemorySorting, filter); this.parent = parent; } /** * Get the hierarchical parent object, where <code>null</code> corresponds * to the root node. * * @return the hierarchical parent object */ public T getParent() { return parent; } /** * Get an Optional of the hierarchical parent object. * * @see #getParent() * @return the result of {@link #getParent()} wrapped by an Optional */ public Optional<T> getParentOptional() { return Optional.ofNullable(parent); } }