1// Protocol Buffers - Google's data interchange format
2// Copyright 2008 Google Inc.  All rights reserved.
3// http://code.google.com/p/protobuf/
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.micro;
32
33import com.google.protobuf.micro.CodedOutputStreamMicro;
34import java.io.IOException;
35
36/**
37 * Abstract interface implemented by Protocol Message objects.
38 *
39 * @author wink@google.com Wink Saville
40 */
41public abstract class MessageMicro {
42    /**
43     * Get the number of bytes required to encode this message.
44     * Returns the cached size or calls getSerializedSize which
45     * sets the cached size. This is used internally when serializing
46     * so the size is only computed once. If a member is modified
47     * then this could be stale call getSerializedSize if in doubt.
48     */
49    abstract public int getCachedSize();
50
51    /**
52     * Computes the number of bytes required to encode this message.
53     * The size is cached and the cached result can be retrieved
54     * using getCachedSize().
55     */
56    abstract public int getSerializedSize();
57
58    /**
59     * Serializes the message and writes it to {@code output}.  This does not
60     * flush or close the stream.
61     */
62    abstract public void writeTo(CodedOutputStreamMicro output) throws java.io.IOException;
63
64    /**
65     * Parse {@code input} as a message of this type and merge it with the
66     * message being built.
67     */
68    abstract public MessageMicro mergeFrom(final CodedInputStreamMicro input) throws IOException;
69
70    /**
71     * Serialize to a byte array.
72     * @return byte array with the serialized data.
73     */
74    public byte[] toByteArray() {
75        final byte[] result = new byte[getSerializedSize()];
76        toByteArray(result, 0, result.length);
77        return result;
78    }
79
80    /**
81     * Serialize to a byte array starting at offset through length. The
82     * method getSerializedSize must have been called prior to calling
83     * this method so the proper length is know.  If an attempt to
84     * write more than length bytes OutOfSpaceException will be thrown
85     * and if length bytes are not written then IllegalStateException
86     * is thrown.
87     * @return byte array with the serialized data.
88     */
89    public void toByteArray(byte [] data, int offset, int length) {
90        try {
91            final CodedOutputStreamMicro output = CodedOutputStreamMicro.newInstance(data, offset, length);
92            writeTo(output);
93            output.checkNoSpaceLeft();
94        } catch (IOException e) {
95            throw new RuntimeException("Serializing to a byte array threw an IOException "
96                    + "(should never happen).");
97        }
98    }
99
100    /**
101     * Parse {@code data} as a message of this type and merge it with the
102     * message being built.
103     */
104    public MessageMicro mergeFrom(final byte[] data) throws InvalidProtocolBufferMicroException {
105        return mergeFrom(data, 0, data.length);
106    }
107
108    /**
109     * Parse {@code data} as a message of this type and merge it with the
110     * message being built.
111     */
112    public MessageMicro mergeFrom(final byte[] data, final int off, final int len)
113            throws InvalidProtocolBufferMicroException {
114        try {
115            final CodedInputStreamMicro input = CodedInputStreamMicro.newInstance(data, off, len);
116            mergeFrom(input);
117            input.checkLastTagWas(0);
118            return this;
119        } catch (InvalidProtocolBufferMicroException e) {
120            throw e;
121        } catch (IOException e) {
122            throw new RuntimeException("Reading from a byte array threw an IOException (should "
123                    + "never happen).");
124        }
125    }
126
127    /**
128     * Called by subclasses to parse an unknown field.
129     * @return {@code true} unless the tag is an end-group tag.
130     */
131    protected boolean parseUnknownField(
132        final CodedInputStreamMicro input,
133        final int tag) throws IOException {
134      return input.skipField(tag);
135    }
136}
137