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 public class LfsGson {
58 private static final Gson gson = new GsonBuilder()
59 .setFieldNamingPolicy(FieldNamingPolicy.LOWER_CASE_WITH_UNDERSCORES)
60 .disableHtmlEscaping()
61 .create();
62
63 /**
64 * Wrapper class only used for serialization of error messages.
65 */
66 static class Error {
67 String message;
68
69 Error(String m) {
70 this.message = m;
71 }
72 }
73
74 /**
75 * Serializes the specified object into its equivalent Json representation.
76 *
77 * @param src
78 * the object for which Json representation is to be created. If
79 * this is a String, it is wrapped in an instance of
80 * {@link org.eclipse.jgit.lfs.server.internal.LfsGson.Error}.
81 * @param writer
82 * Writer to which the Json representation needs to be written
83 * @throws com.google.gson.JsonIOException
84 * if there was a problem writing to the writer
85 * @see Gson#toJson(Object, Appendable)
86 */
87 public static void toJson(Object src, Appendable writer)
88 throws JsonIOException {
89 if (src instanceof String) {
90 gson.toJson(new Error((String) src), writer);
91 } else {
92 gson.toJson(src, writer);
93 }
94 }
95
96 /**
97 * Deserializes the Json read from the specified reader into an object of
98 * the specified type.
99 *
100 * @param json
101 * reader producing json from which the object is to be
102 * deserialized
103 * @param classOfT
104 * specified type to deserialize
105 * @return an Object of type T
106 * @throws com.google.gson.JsonIOException
107 * if there was a problem reading from the Reader
108 * @throws com.google.gson.JsonSyntaxException
109 * if json is not a valid representation for an object of type
110 * @see Gson#fromJson(Reader, java.lang.reflect.Type)
111 * @param <T>
112 * a T object.
113 */
114 public static <T> T fromJson(Reader json, Class<T> classOfT)
115 throws JsonSyntaxException, JsonIOException {
116 return gson.fromJson(json, classOfT);
117 }
118 }