1 /*
2 * Copyright (C) 2017, David Pursehouse <david.pursehouse@gmail.com>
3 * and other copyright owners as documented in the project's IP log.
4 *
5 * This program and the accompanying materials are made available
6 * under the terms of the Eclipse Distribution License v1.0 which
7 * accompanies this distribution, is reproduced below, and is
8 * available at http://www.eclipse.org/org/documents/edl-v10.php
9 *
10 * All rights reserved.
11 *
12 * Redistribution and use in source and binary forms, with or
13 * without modification, are permitted provided that the following
14 * conditions are met:
15 *
16 * - Redistributions of source code must retain the above copyright
17 * notice, this list of conditions and the following disclaimer.
18 *
19 * - Redistributions in binary form must reproduce the above
20 * copyright notice, this list of conditions and the following
21 * disclaimer in the documentation and/or other materials provided
22 * with the distribution.
23 *
24 * - Neither the name of the Eclipse Foundation, Inc. nor the
25 * names of its contributors may be used to endorse or promote
26 * products derived from this software without specific prior
27 * written permission.
28 *
29 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND
30 * CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES,
31 * INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
32 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
33 * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR
34 * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
35 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
36 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
37 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
38 * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
39 * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
40 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
41 * ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
42 */
43
44 package org.eclipse.jgit.lfs.server.internal;
45
46 import java.io.Reader;
47
48 import com.google.gson.FieldNamingPolicy;
49 import com.google.gson.Gson;
50 import com.google.gson.GsonBuilder;
51 import com.google.gson.JsonIOException;
52 import com.google.gson.JsonSyntaxException;
53
54 /**
55 * Wrapper for {@link com.google.gson.Gson} used by LFS servlets.
56 *
57 * @since 4.10.0
58 */
59 public class LfsGson {
60 private static final Gson gson = new GsonBuilder()
61 .setFieldNamingPolicy(FieldNamingPolicy.LOWER_CASE_WITH_UNDERSCORES)
62 .disableHtmlEscaping()
63 .create();
64
65 /**
66 * Wrapper class only used for serialization of error messages.
67 */
68 static class Error {
69 String message;
70
71 Error(String m) {
72 this.message = m;
73 }
74 }
75
76 /**
77 * Serializes the specified object into its equivalent Json representation.
78 *
79 * @param src
80 * the object for which Json representation is to be created. If
81 * this is a String, it is wrapped in an instance of
82 * {@link org.eclipse.jgit.lfs.server.internal.LfsGson.Error}.
83 * @param writer
84 * Writer to which the Json representation needs to be written
85 * @throws com.google.gson.JsonIOException
86 * if there was a problem writing to the writer
87 * @see Gson#toJson(Object, Appendable)
88 */
89 public static void toJson(Object src, Appendable writer)
90 throws JsonIOException {
91 if (src instanceof String) {
92 gson.toJson(new Error((String) src), writer);
93 } else {
94 gson.toJson(src, writer);
95 }
96 }
97
98 /**
99 * Deserializes the Json read from the specified reader into an object of
100 * the specified type.
101 *
102 * @param json
103 * reader producing json from which the object is to be
104 * deserialized
105 * @param classOfT
106 * specified type to deserialize
107 * @return an Object of type T
108 * @throws com.google.gson.JsonIOException
109 * if there was a problem reading from the Reader
110 * @throws com.google.gson.JsonSyntaxException
111 * if json is not a valid representation for an object of type
112 * @see Gson#fromJson(Reader, java.lang.reflect.Type)
113 * @param <T>
114 * a T object.
115 */
116 public static <T> T fromJson(Reader json, Class<T> classOfT)
117 throws JsonSyntaxException, JsonIOException {
118 return gson.fromJson(json, classOfT);
119 }
120 }