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1 | package be.nikiroo.utils.serial; |
2 | ||
3 | import java.io.BufferedReader; | |
4 | import java.io.IOException; | |
5 | import java.io.InputStreamReader; | |
6 | import java.io.OutputStreamWriter; | |
7 | import java.net.Socket; | |
8 | ||
9 | import be.nikiroo.utils.Version; | |
10 | ||
f157aed8 NR |
11 | /** |
12 | * Base class used for the client/server basic handling. | |
13 | * <p> | |
14 | * It represents a single action: a client is expected to only execute one | |
15 | * action, while a server is expected to execute one action for each client | |
16 | * action. | |
17 | * | |
18 | * @author niki | |
19 | */ | |
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20 | abstract class ConnectAction { |
21 | private Socket s; | |
22 | private boolean server; | |
23 | private Version version; | |
f157aed8 | 24 | private Version clientVersion; |
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25 | |
26 | private Object lock = new Object(); | |
27 | private BufferedReader in; | |
28 | private OutputStreamWriter out; | |
29 | private boolean contentToSend; | |
30 | ||
f157aed8 NR |
31 | /** |
32 | * Method that will be called when an action is performed on either the | |
33 | * client or server this {@link ConnectAction} represent. | |
34 | * | |
35 | * @param version | |
36 | * the counter part version | |
37 | * | |
38 | * @throws Exception | |
39 | * in case of I/O error | |
40 | */ | |
41 | abstract protected void action(Version version) throws Exception; | |
42 | ||
43 | /** | |
44 | * Method called when we negotiate the version with the client. | |
45 | * <p> | |
46 | * Thus, it is only called on the server. | |
47 | * <p> | |
48 | * Will return the actual server version by default. | |
49 | * | |
50 | * @param clientVersion | |
51 | * the client version | |
52 | * | |
53 | * @return the version to send to the client | |
54 | */ | |
55 | abstract protected Version negotiateVersion(Version clientVersion); | |
56 | ||
57 | /** | |
58 | * Handler called when an unexpected error occurs in the code. | |
59 | * | |
60 | * @param e | |
61 | * the exception that occurred | |
62 | */ | |
63 | abstract protected void onError(Exception e); | |
ce0974c4 | 64 | |
f157aed8 NR |
65 | /** |
66 | * Create a new {@link ConnectAction}. | |
67 | * | |
68 | * @param s | |
69 | * the socket to bind to | |
70 | * @param server | |
71 | * TRUE for a server action, FALSE for a client action (will | |
72 | * impact the process) | |
73 | * @param version | |
74 | * the version of this client-or-server | |
75 | */ | |
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76 | protected ConnectAction(Socket s, boolean server, Version version) { |
77 | this.s = s; | |
78 | this.server = server; | |
79 | ||
80 | if (version == null) { | |
81 | this.version = new Version(); | |
82 | } else { | |
83 | this.version = version; | |
84 | } | |
f157aed8 NR |
85 | |
86 | clientVersion = new Version(); | |
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87 | } |
88 | ||
f157aed8 NR |
89 | /** |
90 | * The version of this client-or-server. | |
91 | * | |
92 | * @return the version | |
93 | */ | |
94 | public Version getVersion() { | |
95 | return version; | |
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96 | } |
97 | ||
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98 | /** |
99 | * Actually start the process (this is synchronous). | |
100 | */ | |
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101 | public void connect() { |
102 | try { | |
103 | in = new BufferedReader(new InputStreamReader(s.getInputStream(), | |
104 | "UTF-8")); | |
105 | try { | |
106 | out = new OutputStreamWriter(s.getOutputStream(), "UTF-8"); | |
107 | try { | |
108 | if (server) { | |
f157aed8 | 109 | action(clientVersion); |
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110 | } else { |
111 | String v = sendString("VERSION " + version.toString()); | |
112 | if (v != null && v.startsWith("VERSION ")) { | |
113 | v = v.substring("VERSION ".length()); | |
114 | } | |
115 | ||
116 | action(new Version(v)); | |
117 | } | |
118 | } finally { | |
119 | out.close(); | |
120 | } | |
121 | } finally { | |
122 | in.close(); | |
123 | } | |
124 | } catch (Exception e) { | |
125 | onError(e); | |
126 | } finally { | |
127 | try { | |
128 | s.close(); | |
129 | } catch (Exception e) { | |
130 | onError(e); | |
131 | } | |
132 | } | |
133 | } | |
134 | ||
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135 | /** |
136 | * Serialise and send the given object to the counter part (and, only for | |
137 | * client, return the deserialised answer -- the server will always receive | |
138 | * NULL). | |
139 | * | |
140 | * @param data | |
141 | * the data to send | |
142 | * | |
143 | * @return the answer (which can be NULL) if this action is a client, always | |
144 | * NULL if it is a server | |
145 | * | |
146 | * @throws IOException | |
147 | * in case of I/O error | |
148 | * @throws NoSuchFieldException | |
149 | * if the serialised data contains information about a field | |
150 | * which does actually not exist in the class we know of | |
151 | * @throws NoSuchMethodException | |
152 | * if a class described in the serialised data cannot be created | |
153 | * because it is not compatible with this code | |
154 | * @throws ClassNotFoundException | |
155 | * if a class described in the serialised data cannot be found | |
156 | */ | |
157 | protected Object send(Object data) throws IOException, | |
158 | NoSuchFieldException, NoSuchMethodException, ClassNotFoundException { | |
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159 | synchronized (lock) { |
160 | String rep = sendString(new Exporter().append(data).toString(true)); | |
08a58812 NR |
161 | if (rep != null) { |
162 | return new Importer().read(rep).getValue(); | |
163 | } | |
164 | ||
165 | return null; | |
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166 | } |
167 | } | |
168 | ||
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169 | /** |
170 | * Reserved for the server: flush the data to the client and retrieve its | |
171 | * answer. | |
172 | * <p> | |
173 | * Also used internally for the client (only do something if there is | |
174 | * contentToSend). | |
175 | * <p> | |
176 | * Will only flush the data if there is contentToSend. | |
177 | * | |
178 | * @return the deserialised answer (which can actually be NULL) | |
179 | * | |
180 | * @throws IOException | |
181 | * in case of I/O error | |
182 | * @throws NoSuchFieldException | |
183 | * if the serialised data contains information about a field | |
184 | * which does actually not exist in the class we know of | |
185 | * @throws NoSuchMethodException | |
186 | * if a class described in the serialised data cannot be created | |
187 | * because it is not compatible with this code | |
188 | * @throws ClassNotFoundException | |
189 | * if a class described in the serialised data cannot be found | |
190 | * @throws java.lang.NullPointerException | |
191 | * if the counter part has no data to send | |
192 | */ | |
193 | protected Object rec() throws IOException, NoSuchFieldException, | |
194 | NoSuchMethodException, ClassNotFoundException, | |
195 | java.lang.NullPointerException { | |
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196 | String str = flushString(); |
197 | if (str == null) { | |
f157aed8 | 198 | throw new NullPointerException("No more data available"); |
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199 | } |
200 | ||
201 | return new Importer().read(str).getValue(); | |
202 | } | |
203 | ||
cd0c27d2 | 204 | /** |
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205 | * Send the given string to the counter part (and, only for client, return |
206 | * the answer -- the server will always receive NULL). | |
cd0c27d2 | 207 | * |
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208 | * @param line |
209 | * the data to send (we will add a line feed) | |
cd0c27d2 | 210 | * |
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211 | * @return the answer if this action is a client (without the added line |
212 | * feed), NULL if it is a server | |
213 | * | |
214 | * @throws IOException | |
215 | * in case of I/O error | |
cd0c27d2 | 216 | */ |
f157aed8 | 217 | protected String sendString(String line) throws IOException { |
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218 | synchronized (lock) { |
219 | out.write(line); | |
220 | out.write("\n"); | |
221 | ||
222 | if (server) { | |
223 | out.flush(); | |
224 | return null; | |
ce0974c4 | 225 | } |
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226 | |
227 | contentToSend = true; | |
228 | return flushString(); | |
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229 | } |
230 | } | |
231 | ||
f157aed8 NR |
232 | /** |
233 | * Reserved for the server (externally): flush the data to the client and | |
234 | * retrieve its answer. | |
235 | * <p> | |
236 | * Also used internally for the client (only do something if there is | |
237 | * contentToSend). | |
238 | * <p> | |
239 | * Will only flush the data if there is contentToSend. | |
240 | * | |
241 | * @return the answer (which can be NULL) | |
242 | * | |
243 | * @throws IOException | |
244 | * in case of I/O error | |
245 | */ | |
246 | protected String flushString() throws IOException { | |
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247 | synchronized (lock) { |
248 | if (server || contentToSend) { | |
249 | if (contentToSend) { | |
250 | out.flush(); | |
251 | contentToSend = false; | |
252 | } | |
253 | ||
254 | String line = in.readLine(); | |
255 | if (server && line != null && line.startsWith("VERSION ")) { | |
256 | // "VERSION client-version" (VERSION 1.0.0) | |
257 | Version clientVersion = new Version( | |
258 | line.substring("VERSION ".length())); | |
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259 | this.clientVersion = clientVersion; |
260 | Version v = negotiateVersion(clientVersion); | |
261 | if (v == null) { | |
262 | v = new Version(); | |
263 | } | |
264 | sendString("VERSION " + v.toString()); | |
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265 | |
266 | line = in.readLine(); | |
267 | } | |
268 | ||
269 | return line; | |
ce0974c4 | 270 | } |
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271 | |
272 | return null; | |
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273 | } |
274 | } | |
275 | } |