1// Protocol Buffers - Google's data interchange format
2// Copyright 2008 Google Inc.  All rights reserved.
3// https://developers.google.com/protocol-buffers/
4//
5// Redistribution and use in source and binary forms, with or without
6// modification, are permitted provided that the following conditions are
7// met:
8//
9//     * Redistributions of source code must retain the above copyright
10// notice, this list of conditions and the following disclaimer.
11//     * Redistributions in binary form must reproduce the above
12// copyright notice, this list of conditions and the following disclaimer
13// in the documentation and/or other materials provided with the
14// distribution.
15//     * Neither the name of Google Inc. nor the names of its
16// contributors may be used to endorse or promote products derived from
17// this software without specific prior written permission.
18//
19// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
20// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
21// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
22// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
23// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
24// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
25// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
26// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
27// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
28// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
29// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
30
31package com.google.protobuf;
32
33import java.util.Collection;
34import java.util.List;
35
36/**
37 * An interface extending {@code List<String>} that also provides access to the
38 * items of the list as UTF8-encoded ByteString or byte[] objects. This is
39 * used by the protocol buffer implementation to support lazily converting bytes
40 * parsed over the wire to String objects until needed and also increases the
41 * efficiency of serialization if the String was never requested as the
42 * ByteString or byte[] is already cached. The ByteString methods are used in
43 * immutable API only and byte[] methods used in mutable API only for they use
44 * different representations for string/bytes fields.
45 *
46 * @author jonp@google.com (Jon Perlow)
47 */
48public interface LazyStringList extends ProtocolStringList {
49
50  /**
51   * Returns the element at the specified position in this list as a ByteString.
52   *
53   * @param index index of the element to return
54   * @return the element at the specified position in this list
55   * @throws IndexOutOfBoundsException if the index is out of range
56   *         ({@code index < 0 || index >= size()})
57   */
58  ByteString getByteString(int index);
59
60  /**
61   * Returns the element at the specified position in this list as byte[].
62   *
63   * @param index index of the element to return
64   * @return the element at the specified position in this list
65   * @throws IndexOutOfBoundsException if the index is out of range
66   *         ({@code index < 0 || index >= size()})
67   */
68  byte[] getByteArray(int index);
69
70  /**
71   * Appends the specified element to the end of this list (optional
72   * operation).
73   *
74   * @param element element to be appended to this list
75   * @throws UnsupportedOperationException if the <tt>add</tt> operation
76   *         is not supported by this list
77   */
78  void add(ByteString element);
79
80  /**
81   * Appends the specified element to the end of this list (optional
82   * operation).
83   *
84   * @param element element to be appended to this list
85   * @throws UnsupportedOperationException if the <tt>add</tt> operation
86   *         is not supported by this list
87   */
88  void add(byte[] element);
89
90  /**
91   * Replaces the element at the specified position in this list with the
92   * specified element (optional operation).
93   *
94   * @param index index of the element to replace
95   * @param element the element to be stored at the specified position
96   * @throws UnsupportedOperationException if the <tt>set</tt> operation
97   *         is not supported by this list
98   *         IndexOutOfBoundsException if the index is out of range
99   *         ({@code index < 0 || index >= size()})
100   */
101  void set(int index, ByteString element);
102
103  /**
104   * Replaces the element at the specified position in this list with the
105   * specified element (optional operation).
106   *
107   * @param index index of the element to replace
108   * @param element the element to be stored at the specified position
109   * @throws UnsupportedOperationException if the <tt>set</tt> operation
110   *         is not supported by this list
111   *         IndexOutOfBoundsException if the index is out of range
112   *         ({@code index < 0 || index >= size()})
113   */
114  void set(int index, byte[] element);
115
116  /**
117   * Appends all elements in the specified ByteString collection to the end of
118   * this list.
119   *
120   * @param c collection whose elements are to be added to this list
121   * @return true if this list changed as a result of the call
122   * @throws UnsupportedOperationException if the <tt>addAllByteString</tt>
123   *         operation is not supported by this list
124   */
125  boolean addAllByteString(Collection<? extends ByteString> c);
126
127  /**
128   * Appends all elements in the specified byte[] collection to the end of
129   * this list.
130   *
131   * @param c collection whose elements are to be added to this list
132   * @return true if this list changed as a result of the call
133   * @throws UnsupportedOperationException if the <tt>addAllByteArray</tt>
134   *         operation is not supported by this list
135   */
136  boolean addAllByteArray(Collection<byte[]> c);
137
138  /**
139   * Returns an unmodifiable List of the underlying elements, each of which is
140   * either a {@code String} or its equivalent UTF-8 encoded {@code ByteString}
141   * or byte[]. It is an error for the caller to modify the returned
142   * List, and attempting to do so will result in an
143   * {@link UnsupportedOperationException}.
144   */
145  List<?> getUnderlyingElements();
146
147  /**
148   * Merges all elements from another LazyStringList into this one. This method
149   * differs from {@link #addAll(Collection)} on that underlying byte arrays are
150   * copied instead of reference shared. Immutable API doesn't need to use this
151   * method as byte[] is not used there at all.
152   */
153  void mergeFrom(LazyStringList other);
154
155  /**
156   * Returns a mutable view of this list. Changes to the view will be made into
157   * the original list. This method is used in mutable API only.
158   */
159  List<byte[]> asByteArrayList();
160
161  /** Returns an unmodifiable view of the list. */
162  LazyStringList getUnmodifiableView();
163}
164