1 /*
2 * Licensed to the Apache Software Foundation (ASF) under one or more
3 * contributor license agreements. See the NOTICE file distributed with
4 * this work for additional information regarding copyright ownership.
5 * The ASF licenses this file to You under the Apache License, Version 2.0
6 * (the "License"); you may not use this file except in compliance with
7 * the License. You may obtain a copy of the License at
8 *
9 * http://www.apache.org/licenses/LICENSE-2.0
10 *
11 * Unless required by applicable law or agreed to in writing, software
12 * distributed under the License is distributed on an "AS IS" BASIS,
13 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
14 * See the License for the specific language governing permissions and
15 * limitations under the License.
16 */
17 package org.apache.commons.vfs2.provider;
18
19 import java.util.ArrayList;
20 import java.util.stream.Stream;
21
22 import org.apache.commons.vfs2.FileSystemException;
23
24 /**
25 * A {@link VfsComponent} that contains a set of subcomponents.
26 */
27 public abstract class AbstractVfsContainer extends AbstractVfsComponent {
28
29 /**
30 * The components contained by this component.
31 */
32 private final ArrayList<Object> components = new ArrayList<>(); // @GuardedBy("self")
33
34 /**
35 * Constructs a new instance for subclasses.
36 */
37 public AbstractVfsContainer() {
38 // empty
39 }
40
41 /**
42 * Adds a subcomponent to this component.
43 * <p>
44 * If the sub-component implements {@link VfsComponent}, it is initialized. All sub-components are closed when this
45 * component is closed.
46 * </p>
47 *
48 * @param component the component to add.
49 * @throws FileSystemException if any error occurs.
50 */
51 protected void addComponent(final Object component) throws FileSystemException {
52 synchronized (components) {
53 if (!components.contains(component)) {
54 // Initialize
55 if (component instanceof VfsComponent) {
56 final VfsComponent vfsComponent = (VfsComponent) component;
57 vfsComponent.setLogger(getLogger());
58 vfsComponent.setContext(getContext());
59 vfsComponent.init();
60 }
61 // Keep track of component, to close it later
62 components.add(component);
63 }
64 }
65 }
66
67 /**
68 * Closes the subcomponents of this component.
69 */
70 @Override
71 public void close() {
72 final Object[] toclose;
73 synchronized (components) {
74 toclose = components.toArray();
75 components.clear();
76 }
77 // Close all components
78 Stream.of(toclose).filter(VfsComponent.class::isInstance)
79 .forEach(component -> ((VfsComponent) component).close());
80 }
81
82 /**
83 * Removes a subcomponent from this component.
84 *
85 * @param component the component to remove.
86 */
87 protected void removeComponent(final Object component) {
88 synchronized (components) {
89 // multiple instances should not happen
90 components.remove(component);
91 }
92 }
93 }