1/* Licensed to the Apache Software Foundation (ASF) under one or more
2 * contributor license agreements.  See the NOTICE file distributed with
3 * this work for additional information regarding copyright ownership.
4 * The ASF licenses this file to You under the Apache License, Version 2.0
5 * (the "License"); you may not use this file except in compliance with
6 * the License.  You may obtain a copy of the License at
7 *
8 *     http://www.apache.org/licenses/LICENSE-2.0
9 *
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
15 */
16
17package java.nio;
18
19import java.io.Closeable;
20import java.io.FileDescriptor;
21import java.io.IOException;
22import java.nio.channels.ClosedChannelException;
23import java.nio.channels.FileChannel;
24import java.util.Set;
25
26/**
27 * @hide internal use only
28 */
29public final class NioUtils {
30    private NioUtils() {
31    }
32
33    public static void freeDirectBuffer(ByteBuffer buffer) {
34        if (buffer == null) {
35            return;
36        }
37        ((DirectByteBuffer) buffer).free();
38    }
39
40    /**
41     * Returns the int file descriptor from within the given FileChannel 'fc'.
42     */
43    public static FileDescriptor getFD(FileChannel fc) {
44        return ((FileChannelImpl) fc).getFD();
45    }
46
47    /**
48     * Helps bridge between io and nio.
49     */
50    public static FileChannel newFileChannel(Closeable ioObject, FileDescriptor fd, int mode) {
51        return new FileChannelImpl(ioObject, fd, mode);
52    }
53
54    /**
55     * Exposes the array backing a non-direct ByteBuffer, even if the ByteBuffer is read-only.
56     * Normally, attempting to access the array backing a read-only buffer throws.
57     */
58    public static byte[] unsafeArray(ByteBuffer b) {
59        return ((ByteArrayBuffer) b).backingArray;
60    }
61
62    /**
63     * Exposes the array offset for the array backing a non-direct ByteBuffer,
64     * even if the ByteBuffer is read-only.
65     */
66    public static int unsafeArrayOffset(ByteBuffer b) {
67        return ((ByteArrayBuffer) b).arrayOffset;
68    }
69}
70