1 /**
2 * This file Copyright (c) 2018 Magnolia International
3 * Ltd. (http://www.magnolia-cms.com). All rights reserved.
4 *
5 *
6 * This file is dual-licensed under both the Magnolia
7 * Network Agreement and the GNU General Public License.
8 * You may elect to use one or the other of these licenses.
9 *
10 * This file is distributed in the hope that it will be
11 * useful, but AS-IS and WITHOUT ANY WARRANTY; without even the
12 * implied warranty of MERCHANTABILITY or FITNESS FOR A
13 * PARTICULAR PURPOSE, TITLE, or NONINFRINGEMENT.
14 * Redistribution, except as permitted by whichever of the GPL
15 * or MNA you select, is prohibited.
16 *
17 * 1. For the GPL license (GPL), you can redistribute and/or
18 * modify this file under the terms of the GNU General
19 * Public License, Version 3, as published by the Free Software
20 * Foundation. You should have received a copy of the GNU
21 * General Public License, Version 3 along with this program;
22 * if not, write to the Free Software Foundation, Inc., 51
23 * Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
24 *
25 * 2. For the Magnolia Network Agreement (MNA), this file
26 * and the accompanying materials are made available under the
27 * terms of the MNA which accompanies this distribution, and
28 * is available at http://www.magnolia-cms.com/mna.html
29 *
30 * Any modifications to this file must keep this entire header
31 * intact.
32 *
33 */
34 package info.magnolia.ui.framework.datasource.components;
35
36 import java.util.ArrayList;
37 import java.util.Arrays;
38 import java.util.Collection;
39 import java.util.Collections;
40 import java.util.Optional;
41 import java.util.function.Function;
42 import java.util.stream.Stream;
43
44 /**
45 * Represents a selection of one of more items. Provides some convenience method around selections to facilitate usage
46 * with Java's stream API and lambdas.
47 * @param <T> item type.
48 */
49 public class SelectedItems<T> {
50
51 private ArrayList<T> selection = new ArrayList<>();
52
53 private SelectedItems(Collection<T> collection) {
54 selection.addAll(collection);
55 }
56
57 public static <T> SelectedItems<T> empty() {
58 return SelectedItems.of(Collections.emptyList());
59 }
60
61 @SafeVarargs
62 public static <T> SelectedItems<T> of(T... t) {
63 return SelectedItems.of(Arrays.asList(t));
64 }
65
66 public static <T> SelectedItems<T> of(Collection<T> t) {
67 return new SelectedItems<>(t);
68 }
69
70 public Optional<T> getFirst() {
71 return selection.stream().findFirst();
72 }
73
74 public Stream<T> stream() {
75 return selection.stream();
76 }
77
78 public int size() {
79 return selection.size();
80 }
81
82 public <U> Optional<U> ifSingle(Function<T, U> function) {
83 if (size() == 1) {
84 return getFirst().map(function);
85 } else {
86 return Optional.empty();
87 }
88 }
89 }