1 /*
2 * Licensed to the Apache Software Foundation (ASF) under one
3 * or more contributor license agreements. See the NOTICE file
4 * distributed with this work for additional information
5 * regarding copyright ownership. The ASF licenses this file
6 * to you under the Apache License, Version 2.0 (the
7 * "License"); you may not use this file except in compliance
8 * with the License. You may obtain a copy of the License at
9 *
10 * http://www.apache.org/licenses/LICENSE-2.0
11 *
12 * Unless required by applicable law or agreed to in writing,
13 * software distributed under the License is distributed on an
14 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
15 * KIND, either express or implied. See the License for the
16 * specific language governing permissions and limitations
17 * under the License.
18 */
19 package org.apache.maven.plugin.compiler;
20
21 import java.util.Collection;
22 import java.util.Collections;
23 import java.util.Set;
24 import java.util.TreeSet;
25
26 /**
27 * Show the modifications between two lists.
28 */
29 final class DeltaList<E extends Comparable<E>> {
30
31 private final Set<E> added = new TreeSet<>();
32 private final Set<E> removed = new TreeSet<>();
33 private final boolean hasChanged;
34
35 DeltaList(Collection<E> oldList, Collection<E> newList) {
36 for (E newListItem : newList) {
37 if (!oldList.contains(newListItem)) {
38 added.add(newListItem);
39 }
40 }
41 for (E oldListItem : oldList) {
42 if (!newList.contains(oldListItem)) {
43 removed.add(oldListItem);
44 }
45 }
46 this.hasChanged = !added.isEmpty() || !removed.isEmpty();
47 }
48
49 Collection<E> getAdded() {
50 return Collections.unmodifiableCollection(added);
51 }
52
53 Collection<E> getRemoved() {
54 return Collections.unmodifiableCollection(removed);
55 }
56
57 boolean hasChanged() {
58 return hasChanged;
59 }
60 }