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.api.services;
20
21 import java.util.ArrayList;
22 import java.util.Collection;
23 import java.util.Collections;
24
25 import org.apache.maven.api.Session;
26 import org.apache.maven.api.annotations.Experimental;
27 import org.apache.maven.api.annotations.Nonnull;
28
29 /**
30 * Base class for requests.
31 *
32 * @since 4.0
33 */
34 @Experimental
35 abstract class BaseRequest {
36
37 private final Session session;
38
39 protected BaseRequest(@Nonnull Session session) {
40 this.session = nonNull(session, "session cannot be null");
41 }
42
43 @Nonnull
44 public Session getSession() {
45 return session;
46 }
47
48 public static <T> T nonNull(T obj, String message) {
49 if (obj == null) {
50 throw new IllegalArgumentException(message);
51 }
52 return obj;
53 }
54
55 protected static <T> Collection<T> unmodifiable(Collection<T> obj) {
56 return obj != null && !obj.isEmpty()
57 ? Collections.unmodifiableCollection(new ArrayList<>(obj))
58 : Collections.emptyList();
59 }
60 }