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1
7 package org.jboss.web.loadbalancer.scheduler;
8
9 import java.net.MalformedURLException  ;
10 import java.net.URL ;
11 import java.util.ArrayList ;
12 import java.util.Iterator ;
13 import javax.management.MBeanServer ;
14 import javax.management.Notification ;
15 import javax.management.NotificationFilter ;
16 import javax.management.NotificationListener ;
17 import javax.management.ObjectName ;
18 import javax.servlet.http.Cookie ;
19
20 import org.jboss.mx.util.MBeanServerLocator;
21 import org.jboss.util.xml.XmlHelper;
22 import org.jboss.web.loadbalancer.util.Constants;
23 import org.jboss.web.loadbalancer.util.Request;
24 import org.w3c.dom.Element ;
25 import org.jboss.system.*;
26
27
36 public abstract class AbstractScheduler
37 extends ServiceMBeanSupport
38 implements AbstractSchedulerMBean, NotificationListener
39 {
40 protected ArrayList hostsUp = new ArrayList ();
41 protected ArrayList hostsDown = new ArrayList ();
42 protected String stickyCookieName;
43 protected boolean useStickySession = false;
44 protected Element config;
45
46
50 protected abstract Host getNextHost();
51
52 protected void stopService() throws java.lang.Exception
53 {
54 deregisterHostMBeans();
56 }
57
58
62 public void setConfig(Element config)
63 {
64 this.config = config;
65 }
66
67 protected void createService() throws java.lang.Exception
68 {
69 addHostsFromConfig(config);
71
72 if (XmlHelper.getUniqueChildContent(config, "sticky-session").
74 equalsIgnoreCase("true"))
75 {
76 useStickySession = true;
77 stickyCookieName = XmlHelper.getUniqueChildContent(config,
78 "sticky-session-cookie-name");
79 }
80
81 if (log.isDebugEnabled())
82 {
83 if (useStickySession)
84 {
85 log.debug("Using sticky sessions with Cookie name=" + stickyCookieName);
86 }
87 else
88 {
89 log.debug("Using NO sticky sessions");
90 }
91 }
92 }
93
94 protected synchronized void addHostsFromConfig(Element config) throws
95 Exception
96 {
97 Iterator hostIterator = XmlHelper.getChildrenByTagName(XmlHelper.
98 getUniqueChild(config, "hosts"), "host");
99
100 while (hostIterator.hasNext())
101 {
102 Element hostElement = (Element ) hostIterator.next();
103 String hostUrl = XmlHelper.getUniqueChildContent(hostElement, "host-url");
104
105 if (!hostUrl.endsWith("/"))
107 {
108 hostUrl += "/";
109 }
110
111 Host host = addHost(hostUrl);
112
113 try
114 {
115 host.setLbFactor(Integer.parseInt(XmlHelper.getUniqueChildContent(
116 hostElement, "lb-factor")));
117 }
118 catch (Exception e)
119 {
120 log.debug("Could read LbFactor for Host " + host.getUrl() +
121 " - assuming LbFactor 1");
122 host.setLbFactor(1);
123 }
124 }
125 }
126
127 protected ObjectName genObjectNameForHost(Host host) throws Exception
128 {
129 return new ObjectName ("jboss.web.loadbalancer: type=Node, protocol=" +
130 host.getUrl().getProtocol() + ", host=" +
131 host.getUrl().getHost() + ", port=" +
132 (host.getUrl().getPort() == -1 ?
133 host.getUrl().getDefaultPort() :
134 host.getUrl().getPort()));
135 }
136
137 protected void registerHostMBean(Host host)
138 {
139 MBeanServer mbs = MBeanServerLocator.locateJBoss();
140 try
141 {
142 mbs.registerMBean(host, genObjectNameForHost(host));
143 host.addNotificationListener(this,
144 new NotificationFilter ()
145 {
146 public boolean isNotificationEnabled(Notification notification)
147 {
148 return (notification instanceof HostStateChangedNotification);
149 }
150 }
151
152 , host);
153 }
154 catch (Exception ex)
155 {
156 log.error("Could not register HostMBean", ex);
157 }
158 }
159
160 protected void deregisterHostMBean(Host host)
161 {
162 MBeanServer mbs = MBeanServerLocator.locateJBoss();
163 try
164 {
165 mbs.unregisterMBean(genObjectNameForHost(host));
166 host.removeNotificationListener(this);
167 }
168 catch (Exception ex)
169 {
170 log.error("Could not unregister HostMBean", ex);
171 }
172 }
173
174 protected synchronized void deregisterHostMBeans() throws Exception
175 {
176 Iterator hostIterator = hostsUp.iterator();
177
178 while (hostIterator.hasNext())
179 {
180 Host host = (Host) hostIterator.next();
181 deregisterHostMBean(host);
182 }
183
184 hostIterator = hostsDown.iterator();
185 while (hostIterator.hasNext())
186 {
187 Host host = (Host) hostIterator.next();
188 deregisterHostMBean(host);
189 }
190 }
191
192 public void getHost(Request schedRequest) throws
193 NoHostAvailableException
194 {
195 Host host = null;
196
197 host = findStickyHost(schedRequest);
199
200 while (host == null)
202 {
203 if (hostsUp.size() == 0)
204 {
205 throw new NoHostAvailableException("No host to schedule request");
206 }
207 host = getNextHost();
208 }
209
210 schedRequest.setHost(host);
211
212 if (useStickySession)
214 {
215 setStickyCookie(schedRequest);
216 }
217 }
218
219
222 protected void setStickyCookie(Request schedRequest)
223 {
224 Cookie cookie = new Cookie (stickyCookieName,
225 Integer.toString(schedRequest.getHost().hashCode()));
226 cookie.setPath("/");
227 cookie.setMaxAge( -1);
228 schedRequest.getResponse().addCookie(cookie);
229 }
230
231
236 protected Host findStickyHost(Request schedRequest)
237 {
238 Host host = null;
239 if (useStickySession)
240 {
241 Cookie [] cookies = schedRequest.getRequest().getCookies();
242
243 for (int i = 0; cookies != null && i < cookies.length; ++i)
244 {
245 Cookie cookie = cookies[i];
246
247 if (cookie.getName().equals(stickyCookieName))
248 {
249 log.debug("Sticky Cookie found!");
250 int cookieHash = Integer.parseInt(cookie.getValue());
251 Iterator iter = hostsUp.iterator();
252
253 while (iter.hasNext())
254 {
255 Host tempHost = (Host) iter.next();
256 if (tempHost.hashCode() == cookieHash)
257 {
258 host = tempHost;
259 if (log.isDebugEnabled())
260 {
261 log.debug("Sticky Cookie sticks client to host with URL " +
262 tempHost.toString());
263 }
264 break;
265 }
266 }
267 break;
268 }
269 }
270 return host;
271 }
272 else
273 {
274 return null;
275 }
276 }
277
278 protected synchronized void markNodeDown(Host host)
279 {
280 int index = hostsUp.indexOf(host);
281 if (index == -1)
282 {
283 return;
284 }
285 hostsUp.remove(index);
286 hostsDown.add(host);
287
288 }
290
291 protected synchronized void markNodeUp(Host host)
292 {
293 int index = hostsDown.indexOf(host);
294 if (index == -1)
295 {
296 return;
297 }
298 hostsDown.remove(index);
299 hostsUp.add(host);
300
301 }
303
304
309 public ArrayList getHostsDown()
310 {
311 return hostsDown;
312 }
313
314
318 public ArrayList getHostsUp()
319 {
320 return hostsUp;
321 }
322
323
327 public synchronized Host addHost(String hostString) throws
328 MalformedURLException
329 {
330 if (hostString == null)
331 {
332 return null;
333 }
334 if (!hostString.endsWith("/"))
335 {
336 hostString += "/";
337 }
338 Host host = new Host(new URL (hostString));
339
340 if (hostsUp.indexOf(host) > -1 || hostsDown.indexOf(host) > -1)
342 {
343 log.info("Host " + hostString + " already there. Ignored");
344 return null;
345 }
346
347 hostsUp.add(host);
348 registerHostMBean(host);
349
350 return host;
351 }
352
353
357 public synchronized void removeHost(URL url)
358 {
359 if (url == null)
360 {
361 return;
362 }
363 Host host = new Host(url);
364
365 int index = hostsUp.indexOf(host);
366 if (index > -1)
367 {
368 deregisterHostMBean( (Host) hostsUp.get(index));
369 hostsUp.remove(index);
370 }
371
372 index = hostsDown.indexOf(host);
373 if (index > -1)
374 {
375 deregisterHostMBean( (Host) hostsDown.get(index));
376 hostsDown.remove(index);
377 }
378 }
379
380 public void handleNotification(Notification notification, Object handback)
381 {
382 HostStateChangedNotification hscn=(HostStateChangedNotification)notification;
383
384 Host host=(Host)hscn.getSource();
385
386 switch (host.getState())
387 {
388 case Constants.STATE_NODE_UP:
389 markNodeUp(host);
390 break;
391 case Constants.STATE_NODE_DOWN:
392 case Constants.STATE_NODE_FORCED_DOWN:
393 markNodeDown(host);
394 break;
395 }
396 }
397 }
398 |
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