10435e299d70febcdeb83f2f10086c41d85339c3
[fanfix.git] / ConnectAction.java
1 package be.nikiroo.utils.serial.server;
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 import be.nikiroo.utils.serial.Exporter;
11 import be.nikiroo.utils.serial.Importer;
12
13 /**
14 * Base class used for the client/server basic handling.
15 * <p>
16 * It represents a single action: a client is expected to only execute one
17 * action, while a server is expected to execute one action for each client
18 * action.
19 *
20 * @author niki
21 */
22 abstract class ConnectAction {
23 private Socket s;
24 private boolean server;
25 private Version version;
26 private Version clientVersion;
27
28 private Object lock = new Object();
29 private BufferedReader in;
30 private OutputStreamWriter out;
31 private boolean contentToSend;
32
33 /**
34 * Method that will be called when an action is performed on either the
35 * client or server this {@link ConnectAction} represent.
36 *
37 * @param version
38 * the counter part version
39 *
40 * @throws Exception
41 * in case of I/O error
42 */
43 abstract protected void action(Version version) throws Exception;
44
45 /**
46 * Method called when we negotiate the version with the client.
47 * <p>
48 * Thus, it is only called on the server.
49 * <p>
50 * Will return the actual server version by default.
51 *
52 * @param clientVersion
53 * the client version
54 *
55 * @return the version to send to the client
56 */
57 abstract protected Version negotiateVersion(Version clientVersion);
58
59 /**
60 * Handler called when an unexpected error occurs in the code.
61 *
62 * @param e
63 * the exception that occurred
64 */
65 abstract protected void onError(Exception e);
66
67 /**
68 * Create a new {@link ConnectAction}.
69 *
70 * @param s
71 * the socket to bind to
72 * @param server
73 * TRUE for a server action, FALSE for a client action (will
74 * impact the process)
75 * @param version
76 * the version of this client-or-server
77 */
78 protected ConnectAction(Socket s, boolean server, Version version) {
79 this.s = s;
80 this.server = server;
81
82 if (version == null) {
83 this.version = new Version();
84 } else {
85 this.version = version;
86 }
87
88 clientVersion = new Version();
89 }
90
91 /**
92 * The version of this client-or-server.
93 *
94 * @return the version
95 */
96 public Version getVersion() {
97 return version;
98 }
99
100 /**
101 * Actually start the process (this is synchronous).
102 */
103 public void connect() {
104 try {
105 in = new BufferedReader(new InputStreamReader(s.getInputStream(),
106 "UTF-8"));
107 try {
108 out = new OutputStreamWriter(s.getOutputStream(), "UTF-8");
109 try {
110 if (server) {
111 String line = in.readLine();
112 if (line != null && line.startsWith("VERSION ")) {
113 // "VERSION client-version" (VERSION 1.0.0)
114 Version clientVersion = new Version(
115 line.substring("VERSION ".length()));
116 this.clientVersion = clientVersion;
117 Version v = negotiateVersion(clientVersion);
118 if (v == null) {
119 v = new Version();
120 }
121
122 sendString("VERSION " + v.toString());
123 }
124
125 action(clientVersion);
126 } else {
127 String v = sendString("VERSION " + version.toString());
128 if (v != null && v.startsWith("VERSION ")) {
129 v = v.substring("VERSION ".length());
130 }
131
132 action(new Version(v));
133 }
134 } finally {
135 out.close();
136 out = null;
137 }
138 } finally {
139 in.close();
140 in = null;
141 }
142 } catch (Exception e) {
143 onError(e);
144 } finally {
145 try {
146 s.close();
147 } catch (Exception e) {
148 onError(e);
149 }
150 }
151 }
152
153 /**
154 * Serialise and send the given object to the counter part (and, only for
155 * client, return the deserialised answer -- the server will always receive
156 * NULL).
157 *
158 * @param data
159 * the data to send
160 *
161 * @return the answer (which can be NULL) if this action is a client, always
162 * NULL if it is a server
163 *
164 * @throws IOException
165 * in case of I/O error
166 * @throws NoSuchFieldException
167 * if the serialised data contains information about a field
168 * which does actually not exist in the class we know of
169 * @throws NoSuchMethodException
170 * if a class described in the serialised data cannot be created
171 * because it is not compatible with this code
172 * @throws ClassNotFoundException
173 * if a class described in the serialised data cannot be found
174 */
175 protected Object sendObject(Object data) throws IOException,
176 NoSuchFieldException, NoSuchMethodException, ClassNotFoundException {
177 synchronized (lock) {
178 String rep = sendString(new Exporter().append(data).toString(true,
179 true));
180 if (rep != null) {
181 return new Importer().read(rep).getValue();
182 }
183
184 return null;
185 }
186 }
187
188 /**
189 * Reserved for the server: flush the data to the client and retrieve its
190 * answer.
191 * <p>
192 * Also used internally for the client (only do something if there is
193 * contentToSend).
194 * <p>
195 * Will only flush the data if there is contentToSend.
196 *
197 * @return the deserialised answer (which can actually be NULL)
198 *
199 * @throws IOException
200 * in case of I/O error
201 * @throws NoSuchFieldException
202 * if the serialised data contains information about a field
203 * which does actually not exist in the class we know of
204 * @throws NoSuchMethodException
205 * if a class described in the serialised data cannot be created
206 * because it is not compatible with this code
207 * @throws ClassNotFoundException
208 * if a class described in the serialised data cannot be found
209 * @throws java.lang.NullPointerException
210 * if the counter part has no data to send
211 */
212 protected Object recObject() throws IOException, NoSuchFieldException,
213 NoSuchMethodException, ClassNotFoundException,
214 java.lang.NullPointerException {
215 String str = recString();
216 if (str == null) {
217 throw new NullPointerException("No more data available");
218 }
219
220 return new Importer().read(str).getValue();
221 }
222
223 /**
224 * Send the given string to the counter part (and, only for client, return
225 * the answer -- the server will always receive NULL).
226 *
227 * @param line
228 * the data to send (we will add a line feed)
229 *
230 * @return the answer if this action is a client (without the added line
231 * feed), NULL if it is a server
232 *
233 * @throws IOException
234 * in case of I/O error
235 */
236 protected String sendString(String line) throws IOException {
237 synchronized (lock) {
238 out.write(line);
239 out.write("\n");
240
241 if (server) {
242 out.flush();
243 return null;
244 }
245
246 contentToSend = true;
247 return recString();
248 }
249 }
250
251 /**
252 * Reserved for the server (externally): flush the data to the client and
253 * retrieve its answer.
254 * <p>
255 * Also used internally for the client (only do something if there is
256 * contentToSend).
257 * <p>
258 * Will only flush the data if there is contentToSend.
259 *
260 * @return the answer (which can be NULL)
261 *
262 * @throws IOException
263 * in case of I/O error
264 */
265 protected String recString() throws IOException {
266 synchronized (lock) {
267 if (server || contentToSend) {
268 if (contentToSend) {
269 out.flush();
270 contentToSend = false;
271 }
272
273 return in.readLine();
274 }
275
276 return null;
277 }
278 }
279 }