1// Protocol Buffers - Google's data interchange format
2// Copyright 2008 Google Inc.  All rights reserved.
3// https://developers.google.com/protocol-buffers/
4//
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30
31package com.google.protobuf;
32
33import java.io.IOException;
34import java.nio.ByteBuffer;
35
36/**
37 * An output target for raw bytes. This interface provides semantics that support two types of
38 * writing:
39 *
40 * <p/><b>Traditional write operations:</b>
41 * (as defined by {@link java.io.OutputStream}) where the target method is responsible for either
42 * copying the data or completing the write before returning from the method call.
43 *
44 * <p/><b>Lazy write operations:</b> where the caller guarantees that it will never modify the
45 * provided buffer and it can therefore be considered immutable. The target method is free to
46 * maintain a reference to the buffer beyond the scope of the method call (e.g. until the write
47 * operation completes).
48 */
49@ExperimentalApi
50public abstract class ByteOutput {
51  /**
52   * Writes a single byte.
53   *
54   * @param value the byte to be written
55   * @throws IOException thrown if an error occurred while writing
56   */
57  public abstract void write(byte value) throws IOException;
58
59  /**
60   * Writes a sequence of bytes. The {@link ByteOutput} must copy {@code value} if it will
61   * not be processed prior to the return of this method call, since {@code value} may be
62   * reused/altered by the caller.
63   *
64   * <p>NOTE: This method <strong>MUST NOT</strong> modify the {@code value}. Doing so is a
65   * programming error and will lead to data corruption which will be difficult to debug.
66   *
67   * @param value the bytes to be written
68   * @param offset the offset of the start of the writable range
69   * @param length the number of bytes to write starting from {@code offset}
70   * @throws IOException thrown if an error occurred while writing
71   */
72  public abstract void write(byte[] value, int offset, int length) throws IOException;
73
74  /**
75   * Writes a sequence of bytes. The {@link ByteOutput} is free to retain a reference to the value
76   * beyond the scope of this method call (e.g. write later) since it is considered immutable and is
77   * guaranteed not to change by the caller.
78   *
79   * <p>NOTE: This method <strong>MUST NOT</strong> modify the {@code value}. Doing so is a
80   * programming error and will lead to data corruption which will be difficult to debug.
81   *
82   * @param value the bytes to be written
83   * @param offset the offset of the start of the writable range
84   * @param length the number of bytes to write starting from {@code offset}
85   * @throws IOException thrown if an error occurred while writing
86   */
87  public abstract void writeLazy(byte[] value, int offset, int length) throws IOException;
88
89  /**
90   * Writes a sequence of bytes. The {@link ByteOutput} must copy {@code value} if it will
91   * not be processed prior to the return of this method call, since {@code value} may be
92   * reused/altered by the caller.
93   *
94   * <p>NOTE: This method <strong>MUST NOT</strong> modify the {@code value}. Doing so is a
95   * programming error and will lead to data corruption which will be difficult to debug.
96   *
97   * @param value the bytes to be written. Upon returning from this call, the {@code position} of
98   * this buffer will be set to the {@code limit}
99   * @throws IOException thrown if an error occurred while writing
100   */
101  public abstract void write(ByteBuffer value) throws IOException;
102
103  /**
104   * Writes a sequence of bytes. The {@link ByteOutput} is free to retain a reference to the value
105   * beyond the scope of this method call (e.g. write later) since it is considered immutable and is
106   * guaranteed not to change by the caller.
107   *
108   * <p>NOTE: This method <strong>MUST NOT</strong> modify the {@code value}. Doing so is a
109   * programming error and will lead to data corruption which will be difficult to debug.
110   *
111   * @param value the bytes to be written. Upon returning from this call, the {@code position} of
112   * this buffer will be set to the {@code limit}
113   * @throws IOException thrown if an error occurred while writing
114   */
115  public abstract void writeLazy(ByteBuffer value) throws IOException;
116}
117