1 // Protocol Buffers - Google's data interchange format
2 // Copyright 2008 Google Inc. All rights reserved.
3 // http://code.google.com/p/protobuf/
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6 // modification, are permitted provided that the following conditions are
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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
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16 // contributors may be used to endorse or promote products derived from
17 // this software without specific prior written permission.
19 // THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
20 // "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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31 package com.google.protobuf;
33 import java.util.List;
36 * An interface extending {@code List<String>} that also provides access to the
37 * items of the list as UTF8-encoded ByteString objects. This is used by the
38 * protocol buffer implementation to support lazily converting bytes parsed
39 * over the wire to String objects until needed and also increases the
40 * efficiency of serialization if the String was never requested as the
41 * ByteString is already cached.
43 * This only adds additional methods that are required for the use in the
44 * protocol buffer code in order to be able successfully round trip byte arrays
45 * through parsing and serialization without conversion to strings. It's not
46 * attempting to support the functionality of say {@code List<ByteString>}, hence
47 * why only these two very specific methods are added.
49 * @author jonp@google.com (Jon Perlow)
51 public interface LazyStringList extends List<String> {
54 * Returns the element at the specified position in this list as a ByteString.
56 * @param index index of the element to return
57 * @return the element at the specified position in this list
58 * @throws IndexOutOfBoundsException if the index is out of range
59 * ({@code index < 0 || index >= size()})
61 ByteString getByteString(int index);
64 * Appends the specified element to the end of this list (optional
67 * @param element element to be appended to this list
68 * @throws UnsupportedOperationException if the <tt>add</tt> operation
69 * is not supported by this list
71 void add(ByteString element);
74 * Returns an unmodifiable List of the underlying elements, each of
75 * which is either a {@code String} or its equivalent UTF-8 encoded
76 * {@code ByteString}. It is an error for the caller to modify the returned
77 * List, and attempting to do so will result in an
78 * {@link UnsupportedOperationException}.
80 List<?> getUnderlyingElements();