1/*
2 * Copyright (C) 2014 Square, Inc.
3 *
4 * Licensed under the Apache License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * 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 */
16package okio;
17
18import java.io.Closeable;
19import java.io.IOException;
20
21/**
22 * Receives a stream of bytes. Use this interface to write data wherever it's
23 * needed: to the network, storage, or a buffer in memory. Sinks may be layered
24 * to transform received data, such as to compress, encrypt, throttle, or add
25 * protocol framing.
26 *
27 * <p>Most application code shouldn't operate on a sink directly, but rather
28 * {@link BufferedSink} which is both more efficient and more convenient. Use
29 * {@link Okio#buffer(Sink)} to wrap any sink with a buffer.
30 *
31 * <p>Sinks are easy to test: just use an {@link OkBuffer} in your tests, and
32 * read from it to confirm it received the data that was expected.
33 *
34 * <h3>Comparison with OutputStream</h3>
35 * This interface is functionally equivalent to {@link java.io.OutputStream}.
36 *
37 * <p>{@code OutputStream} requires multiple layers when emitted data is
38 * heterogeneous: a {@code DataOutputStream} for primitive values, a {@code
39 * BufferedOutputStream} for buffering, and {@code OutputStreamWriter} for
40 * charset encoding. This class uses {@code BufferedSink} for all of the above.
41 *
42 * <p>Sink is also easier to layer: there is no {@link
43 * java.io.OutputStream#write(int) single-byte write} method that is awkward to
44 * implement efficiently.
45 *
46 * <h3>Interop with OutputStream</h3>
47 * Use {@link Okio#sink} to adapt an {@code OutputStream} to a sink. Use {@link
48 * BufferedSink#outputStream} to adapt a sink to an {@code OutputStream}.
49 */
50public interface Sink extends Closeable {
51  /** Removes {@code byteCount} bytes from {@code source} and appends them to this. */
52  void write(OkBuffer source, long byteCount) throws IOException;
53
54  /** Pushes all buffered bytes to their final destination. */
55  void flush() throws IOException;
56
57  /**
58   * Sets the deadline for all operations on this sink.
59   * @return this sink.
60   */
61  Sink deadline(Deadline deadline);
62
63  /**
64   * Pushes all buffered bytes to their final destination and releases the
65   * resources held by this sink. It is an error to write a closed sink. It is
66   * safe to close a sink more than once.
67   */
68  @Override void close() throws IOException;
69}
70