1 //
2 // ========================================================================
3 // Copyright (c) 1995-2013 Mort Bay Consulting Pty. Ltd.
4 // ------------------------------------------------------------------------
5 // All rights reserved. This program and the accompanying materials
6 // are made available under the terms of the Eclipse Public License v1.0
7 // and Apache License v2.0 which accompanies this distribution.
8 //
9 // The Eclipse Public License is available at
10 // http://www.eclipse.org/legal/epl-v10.html
11 //
12 // The Apache License v2.0 is available at
13 // http://www.opensource.org/licenses/apache2.0.php
14 //
15 // You may elect to redistribute this code under either of these licenses.
16 // ========================================================================
17 //
18
19 package org.eclipse.jetty.util.component;
20
21 import java.io.IOException;
22 import java.util.ArrayList;
23 import java.util.Collection;
24 import java.util.Collections;
25 import java.util.Iterator;
26 import java.util.List;
27 import java.util.concurrent.CopyOnWriteArrayList;
28
29 import org.eclipse.jetty.util.log.Log;
30 import org.eclipse.jetty.util.log.Logger;
31
32 /**
33 * An AggregateLifeCycle is an {@link LifeCycle} implementation for a collection of contained beans.
34 * <p>
35 * Beans can be added the AggregateLifeCycle either as managed beans or as unmanaged beans. A managed bean is started, stopped and destroyed with the aggregate.
36 * An unmanaged bean is associated with the aggregate for the purposes of {@link #dump()}, but it's lifecycle must be managed externally.
37 * <p>
38 * When a bean is added, if it is a {@link LifeCycle} and it is already started, then it is assumed to be an unmanaged bean.
39 * Otherwise the methods {@link #addBean(Object, boolean)}, {@link #manage(Object)} and {@link #unmanage(Object)} can be used to
40 * explicitly control the life cycle relationship.
41 * <p>
42 * If adding a bean that is shared between multiple {@link AggregateLifeCycle} instances, then it should be started before being added, so it is unmanaged, or
43 * the API must be used to explicitly set it as unmanaged.
44 * <p>
45 */
46 public class AggregateLifeCycle extends AbstractLifeCycle implements Destroyable, Dumpable
47 {
48 private static final Logger LOG = Log.getLogger(AggregateLifeCycle.class);
49 private final List<Bean> _beans=new CopyOnWriteArrayList<Bean>();
50 private boolean _started=false;
51
52 private class Bean
53 {
54 Bean(Object b)
55 {
56 _bean=b;
57 }
58 final Object _bean;
59 volatile boolean _managed=true;
60
61 public String toString()
62 {
63 return "{"+_bean+","+_managed+"}";
64 }
65 }
66
67 /* ------------------------------------------------------------ */
68 /**
69 * Start the managed lifecycle beans in the order they were added.
70 * @see org.eclipse.jetty.util.component.AbstractLifeCycle#doStart()
71 */
72 @Override
73 protected void doStart() throws Exception
74 {
75 for (Bean b:_beans)
76 {
77 if (b._managed && b._bean instanceof LifeCycle)
78 {
79 LifeCycle l=(LifeCycle)b._bean;
80 if (!l.isRunning())
81 l.start();
82 }
83 }
84 // indicate that we are started, so that addBean will start other beans added.
85 _started=true;
86 super.doStart();
87 }
88
89 /* ------------------------------------------------------------ */
90 /**
91 * Stop the joined lifecycle beans in the reverse order they were added.
92 * @see org.eclipse.jetty.util.component.AbstractLifeCycle#doStart()
93 */
94 @Override
95 protected void doStop() throws Exception
96 {
97 _started=false;
98 super.doStop();
99 List<Bean> reverse = new ArrayList<Bean>(_beans);
100 Collections.reverse(reverse);
101 for (Bean b:reverse)
102 {
103 if (b._managed && b._bean instanceof LifeCycle)
104 {
105 LifeCycle l=(LifeCycle)b._bean;
106 if (l.isRunning())
107 l.stop();
108 }
109 }
110 }
111
112
113 /* ------------------------------------------------------------ */
114 /**
115 * Destroy the joined Destroyable beans in the reverse order they were added.
116 * @see org.eclipse.jetty.util.component.Destroyable#destroy()
117 */
118 public void destroy()
119 {
120 List<Bean> reverse = new ArrayList<Bean>(_beans);
121 Collections.reverse(reverse);
122 for (Bean b:reverse)
123 {
124 if (b._bean instanceof Destroyable && b._managed)
125 {
126 Destroyable d=(Destroyable)b._bean;
127 d.destroy();
128 }
129 }
130 _beans.clear();
131 }
132
133
134 /* ------------------------------------------------------------ */
135 /** Is the bean contained in the aggregate.
136 * @param bean
137 * @return True if the aggregate contains the bean
138 */
139 public boolean contains(Object bean)
140 {
141 for (Bean b:_beans)
142 if (b._bean==bean)
143 return true;
144 return false;
145 }
146
147 /* ------------------------------------------------------------ */
148 /** Is the bean joined to the aggregate.
149 * @param bean
150 * @return True if the aggregate contains the bean and it is joined
151 */
152 public boolean isManaged(Object bean)
153 {
154 for (Bean b:_beans)
155 if (b._bean==bean)
156 return b._managed;
157 return false;
158 }
159
160 /* ------------------------------------------------------------ */
161 /**
162 * Add an associated bean.
163 * If the bean is a {@link LifeCycle}, then it will be managed if it is not
164 * already started and umanaged if it is already started. The {@link #addBean(Object, boolean)}
165 * method should be used if this is not correct, or the {@link #manage(Object)} and {@link #unmanage(Object)}
166 * methods may be used after an add to change the status.
167 * @param o the bean object to add
168 * @return true if the bean was added or false if it has already been added.
169 */
170 public boolean addBean(Object o)
171 {
172 // beans are joined unless they are started lifecycles
173 return addBean(o,!((o instanceof LifeCycle)&&((LifeCycle)o).isStarted()));
174 }
175
176 /* ------------------------------------------------------------ */
177 /** Add an associated lifecycle.
178 * @param o The lifecycle to add
179 * @param managed True if the LifeCycle is to be joined, otherwise it will be disjoint.
180 * @return true if bean was added, false if already present.
181 */
182 public boolean addBean(Object o, boolean managed)
183 {
184 if (contains(o))
185 return false;
186
187 Bean b = new Bean(o);
188 b._managed=managed;
189 _beans.add(b);
190
191 if (o instanceof LifeCycle)
192 {
193 LifeCycle l=(LifeCycle)o;
194
195 // Start the bean if we are started
196 if (managed && _started)
197 {
198 try
199 {
200 l.start();
201 }
202 catch(Exception e)
203 {
204 throw new RuntimeException (e);
205 }
206 }
207 }
208 return true;
209 }
210
211 /* ------------------------------------------------------------ */
212 /**
213 * Manage a bean by this aggregate, so that it is started/stopped/destroyed with the
214 * aggregate lifecycle.
215 * @param bean The bean to manage (must already have been added).
216 */
217 public void manage(Object bean)
218 {
219 for (Bean b :_beans)
220 {
221 if (b._bean==bean)
222 {
223 b._managed=true;
224 return;
225 }
226 }
227 throw new IllegalArgumentException();
228 }
229
230 /* ------------------------------------------------------------ */
231 /**
232 * Unmanage a bean by this aggregate, so that it is not started/stopped/destroyed with the
233 * aggregate lifecycle.
234 * @param bean The bean to manage (must already have been added).
235 */
236 public void unmanage(Object bean)
237 {
238 for (Bean b :_beans)
239 {
240 if (b._bean==bean)
241 {
242 b._managed=false;
243 return;
244 }
245 }
246 throw new IllegalArgumentException();
247 }
248
249 /* ------------------------------------------------------------ */
250 /** Get dependent beans
251 * @return List of beans.
252 */
253 public Collection<Object> getBeans()
254 {
255 return getBeans(Object.class);
256 }
257
258 /* ------------------------------------------------------------ */
259 /** Get dependent beans of a specific class
260 * @see #addBean(Object)
261 * @param clazz
262 * @return List of beans.
263 */
264 public <T> List<T> getBeans(Class<T> clazz)
265 {
266 ArrayList<T> beans = new ArrayList<T>();
267 for (Bean b:_beans)
268 {
269 if (clazz.isInstance(b._bean))
270 beans.add((T)(b._bean));
271 }
272 return beans;
273 }
274
275
276 /* ------------------------------------------------------------ */
277 /** Get dependent beans of a specific class.
278 * If more than one bean of the type exist, the first is returned.
279 * @see #addBean(Object)
280 * @param clazz
281 * @return bean or null
282 */
283 public <T> T getBean(Class<T> clazz)
284 {
285 for (Bean b:_beans)
286 {
287 if (clazz.isInstance(b._bean))
288 return (T)b._bean;
289 }
290
291 return null;
292 }
293
294 /* ------------------------------------------------------------ */
295 /**
296 * Remove all associated bean.
297 */
298 public void removeBeans ()
299 {
300 _beans.clear();
301 }
302
303 /* ------------------------------------------------------------ */
304 /**
305 * Remove an associated bean.
306 */
307 public boolean removeBean (Object o)
308 {
309 Iterator<Bean> i = _beans.iterator();
310 while(i.hasNext())
311 {
312 Bean b=i.next();
313 if (b._bean==o)
314 {
315 _beans.remove(b);
316 return true;
317 }
318 }
319 return false;
320 }
321
322 /* ------------------------------------------------------------ */
323 public void dumpStdErr()
324 {
325 try
326 {
327 dump(System.err,"");
328 }
329 catch (IOException e)
330 {
331 LOG.warn(e);
332 }
333 }
334
335 /* ------------------------------------------------------------ */
336 public String dump()
337 {
338 return dump(this);
339 }
340
341 /* ------------------------------------------------------------ */
342 public static String dump(Dumpable dumpable)
343 {
344 StringBuilder b = new StringBuilder();
345 try
346 {
347 dumpable.dump(b,"");
348 }
349 catch (IOException e)
350 {
351 LOG.warn(e);
352 }
353 return b.toString();
354 }
355
356 /* ------------------------------------------------------------ */
357 public void dump(Appendable out) throws IOException
358 {
359 dump(out,"");
360 }
361
362 /* ------------------------------------------------------------ */
363 protected void dumpThis(Appendable out) throws IOException
364 {
365 out.append(String.valueOf(this)).append(" - ").append(getState()).append("\n");
366 }
367
368 /* ------------------------------------------------------------ */
369 public static void dumpObject(Appendable out,Object o) throws IOException
370 {
371 try
372 {
373 if (o instanceof LifeCycle)
374 out.append(String.valueOf(o)).append(" - ").append((AbstractLifeCycle.getState((LifeCycle)o))).append("\n");
375 else
376 out.append(String.valueOf(o)).append("\n");
377 }
378 catch(Throwable th)
379 {
380 out.append(" => ").append(th.toString()).append('\n');
381 }
382 }
383
384 /* ------------------------------------------------------------ */
385 public void dump(Appendable out,String indent) throws IOException
386 {
387 dumpThis(out);
388 int size=_beans.size();
389 if (size==0)
390 return;
391 int i=0;
392 for (Bean b : _beans)
393 {
394 i++;
395
396 out.append(indent).append(" +- ");
397 if (b._managed)
398 {
399 if (b._bean instanceof Dumpable)
400 ((Dumpable)b._bean).dump(out,indent+(i==size?" ":" | "));
401 else
402 dumpObject(out,b._bean);
403 }
404 else
405 dumpObject(out,b._bean);
406 }
407
408 if (i!=size)
409 out.append(indent).append(" |\n");
410 }
411
412 /* ------------------------------------------------------------ */
413 public static void dump(Appendable out,String indent,Collection<?>... collections) throws IOException
414 {
415 if (collections.length==0)
416 return;
417 int size=0;
418 for (Collection<?> c : collections)
419 size+=c.size();
420 if (size==0)
421 return;
422
423 int i=0;
424 for (Collection<?> c : collections)
425 {
426 for (Object o : c)
427 {
428 i++;
429 out.append(indent).append(" +- ");
430
431 if (o instanceof Dumpable)
432 ((Dumpable)o).dump(out,indent+(i==size?" ":" | "));
433 else
434 dumpObject(out,o);
435 }
436
437 if (i!=size)
438 out.append(indent).append(" |\n");
439 }
440 }
441 }