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3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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25
26 package com.sun.xml.internal.ws.api.pipe;
27
28 import com.sun.xml.internal.ws.api.message.Message;
29 import com.sun.xml.internal.ws.api.message.Packet;
30 import com.sun.xml.internal.ws.api.pipe.helper.AbstractFilterPipeImpl;
31 import com.sun.xml.internal.ws.api.pipe.helper.AbstractPipeImpl;
32
33 import javax.annotation.PreDestroy;
34 import javax.xml.ws.Dispatch;
35 import javax.xml.ws.Provider;
36 import javax.xml.ws.WebServiceException;
37 import javax.xml.ws.handler.Handler;
38 import javax.xml.ws.handler.LogicalHandler;
39 import javax.xml.ws.handler.MessageContext;
40 import javax.xml.ws.handler.soap.SOAPHandler;
41
42 /**
43 * Abstraction of the intermediate layers in the processing chain
44 * and transport.
45 *
46 * <h2>What is a {@link Pipe}?</h2>
47 * <p>
48 * Transport is a kind of pipe. It sends the {@link Packet}
49 * through, say, HTTP connection, and receives the data back into another {@link Packet}.
50 *
51 * <p>
52 * More often, a pipe is a filter. It acts on a packet,
53 * and then it passes the packet into another pipe. It can
54 * do the same on the way back.
55 *
56 * <p>
57 * For example, XWSS will be a {@link Pipe}
58 * that delegates to another {@link Pipe}, and it can wrap a {@link Packet} into
59 * another {@link Packet} to encrypt the body and add a header, for example.
60 *
61 * <p>
62 * Yet another kind of filter pipe is those that wraps {@link LogicalHandler}
63 * and {@link SOAPHandler}. These pipes are heavy-weight; they often consume
64 * a message in a packet and create a new one, and then pass it to the next pipe.
65 * For performance reason it probably makes sense to have one {@link Pipe}
66 * instance that invokes a series of {@link LogicalHandler}s, another one
67 * for {@link SOAPHandler}.
68 *
69 * <p>
70 * There would be a {@link Pipe} implementation that invokes {@link Provider}.
71 * There would be a {@link Pipe} implementation that invokes a service method
72 * on the user's code.
73 * There would be a {@link Dispatch} implementation that invokes a {@link Pipe}.
74 *
75 * <p>
76 * WS-MEX can be implemented as a {@link Pipe} that looks for
77 * {@link Message#getPayloadNamespaceURI()} and serves the request.
78 *
79 *
80 * <h2>Pipe Lifecycle</h2>
81 * {@link Pipe}line is expensive to set up, so once it's created it will be reused.
82 * A {@link Pipe}line is not reentrant; one pipeline is used to process one request/response
83 * at at time. The same pipeline instance may serve request/response for different threads,
84 * if one comes after another and they don't overlap.
85 * <p>
86 * Where a need arises to process multiple requests concurrently, a pipeline
87 * gets cloned through {@link PipeCloner}. Note that this need may happen on
88 * both server (because it quite often serves multiple requests concurrently)
89 * and client (because it needs to support asynchronous method invocations.)
90 * <p>
91 * Created pipelines (including cloned ones and the original) may be discarded and GCed
92 * at any time at the discretion of whoever owns pipelines. Pipes can, however, expect
93 * at least one copy (or original) of pipeline to live at any given time while a pipeline
94 * owner is interested in the given pipeline configuration (in more concerete terms,
95 * for example, as long as a dispatch object lives, it's going to keep at least one
96 * copy of a pipeline alive.)
97 * <p>
98 * Before a pipeline owner dies, it may invoke {@link #preDestroy()} on the last
99 * remaining pipeline. It is "may" for pipeline owners that live in the client-side
100 * of JAX-WS (such as dispatches and proxies), but it is a "must" for pipeline owners
101 * that live in the server-side of JAX-WS.
102 * <p>
103 * This last invocation gives a chance for some pipes to clean up any state/resource
104 * acquired (such as WS-RM's sequence, WS-Trust's SecurityToken), although as stated above,
105 * this is not required for clients.
106 *
107 *
108 *
109 * <h2>Pipe and State</h2>
110 * <p>
111 * The lifecycle of pipelines is designed to allow a {@link Pipe} to store various
112 * state in easily accessible fashion.
113 *
114 *
115 * <h3>Per-packet state</h3>
116 * <p>
117 * Any information that changes from a packet to packet should be
118 * stored in {@link Packet}. This includes information like
119 * transport-specific headers.
120 *
121 * <h3>Per-thread state</h3>
122 * <p>
123 * Any expensive objects that are non-reentrant can be stored in
124 * instance variables of a {@link Pipe}, since {@link #process(Packet)} is
125 * non reentrant. When a pipe is copied, new instances should be allocated
126 * so that two {@link Pipe} instances don't share thread-unsafe resources.
127 * This includes things like canonicalizers, JAXB unmarshallers, buffers,
128 * and so on.
129 *
130 * <h3>Per-proxy/per-endpoint state</h3>
131 * <p>
132 * Information that is tied to a particular proxy/dispatch can be stored
133 * in a separate object that is referenced from a pipe. When
134 * a new pipe is copied, you can simply hand out a reference to the newly
135 * created one, so that all copied pipes refer to the same instance.
136 * See the following code as an example:
137 *
138 * <pre>
139 * class PipeImpl {
140 * // this object stores per-proxy state
141 * class DataStore {
142 * int counter;
143 * }
144 *
145 * private DataStore ds;
146 *
147 * // create a fresh new pipe
148 * public PipeImpl(...) {
149 * ....
150 * ds = new DataStore();
151 * }
152 *
153 * // copy constructor
154 * private PipeImpl(PipeImpl that, PipeCloner cloner) {
155 * cloner.add(that,this);
156 * ...
157 * this.ds = that.ds;
158 * }
159 *
160 * public PipeImpl copy(PipeCloner pc) {
161 * return new PipeImpl(this,pc);
162 * }
163 * }
164 * </pre>
165 *
166 * <p>
167 * Note that access to such resource often needs to be synchronized,
168 * since multiple copies of pipelines may execute concurrently.
169 *
170 * <p>
171 * If such information is read-only,
172 * it can be stored as instance variables of a pipe,
173 * and its reference copied as pipes get copied. (The only difference between
174 * this and per-thread state is that you just won't allocate new things when
175 * pipes get copied here.)
176 *
177 *
178 * <h3>VM-wide state</h3>
179 * <p>
180 * <tt>static</tt> is always there for you to use.
181 *
182 *
183 *
184 * <h2>Pipes and Handlers</h2>
185 * <p>
186 * JAX-WS has a notion of {@link LogicalHandler} and {@link SOAPHandler}, and
187 * we intend to have one {@link Pipe} implementation that invokes all the
188 * {@link LogicalHandler}s and another {@link Pipe} implementation that invokes
189 * all the {@link SOAPHandler}s. Those implementations need to convert a {@link Message}
190 * into an appropriate format, but grouping all the handlers together eliminates
191 * the intermediate {@link Message} instanciation between such handlers.
192 * <p>
193 * This grouping also allows such implementations to follow the event notifications
194 * to handlers (i.e. {@link Handler#close(MessageContext)} method.
195 *
196 *
197 * <pre>
198 * TODO: Possible types of pipe:
199 * creator: create message from wire
200 * to SAAJ SOAP message
201 * to cached representation
202 * directly to JAXB beans
203 * transformer: transform message from one representation to another
204 * JAXB beans to encoded SOAP message
205 * StAX writing + JAXB bean to encoded SOAP message
206 * modifier: modify message
207 * add SOAP header blocks
208 * security processing
209 * header block processor:
210 * process certain SOAP header blocks
211 * outbound initiator: input from the client
212 * Manage input e.g. JAXB beans and associated with parts of the SOAP message
213 * inbound invoker: invoke the service
214 * Inkoke SEI, e.g. EJB or SEI in servlet.
215 * </pre>
216 *
217 * @see AbstractPipeImpl
218 * @see AbstractFilterPipeImpl
219 * @deprecated
220 * Use {@link Tube}.
221 */
222 public interface Pipe {
223 /**
224 * Sends a {@link Packet} and returns a response {@link Packet} to it.
225 *
226 * @throws WebServiceException
227 * On the server side, this signals an error condition where
228 * a fault reply is in order (or the exception gets eaten by
229 * the top-most transport {@link Pipe} if it's one-way.)
230 * This frees each {@link Pipe} from try/catching a
231 * {@link WebServiceException} in every layer.
232 *
233 * Note that this method is also allowed to return a {@link Packet}
234 * that has a fault as the payload.
235 *
236 * <p>
237 * On the client side, the {@link WebServiceException} thrown
238 * will be propagated all the way back to the calling client
239 * applications. (The consequence of that is that if you are
240 * a filtering {@link Pipe}, you must not catch the exception
241 * that your next {@link Pipe} threw.
242 *
243 * @throws RuntimeException
244 * Other runtime exception thrown by this method must
245 * be treated as a bug in the pipe implementation,
246 * and therefore should not be converted into a fault.
247 * (Otherwise it becomes very difficult to debug implementation
248 * problems.)
249 *
250 * <p>
251 * On the server side, this exception should be most likely
252 * just logged. On the client-side it gets propagated to the
253 * client application.
254 *
255 * <p>
256 * The consequence of this is that if a pipe calls
257 * into an user application (such as {@link SOAPHandler}
258 * or {@link LogicalHandler}), where a {@link RuntimeException}
259 * is *not* a bug in the JAX-WS implementation, it must be catched
260 * and wrapped into a {@link WebServiceException}.
261 *
262 * @param request
263 * The packet that represents a request message. Must not be null.
264 * If the packet has a non-null message, it must be a valid
265 * unconsumed {@link Message}. This message represents the
266 * SOAP message to be sent as a request.
267 * <p>
268 * The packet is also allowed to carry no message, which indicates
269 * that this is an output-only request.
270 * (that's called "solicit", right? - KK)
271 *
272 * @return
273 * The packet that represents a response message. Must not be null.
274 * If the packet has a non-null message, it must be
275 * a valid unconsumed {@link Message}. This message represents
276 * a response to the request message passed as a parameter.
277 * <p>
278 * The packet is also allowed to carry no message, which indicates
279 * that there was no response. This is used for things like
280 * one-way message and/or one-way transports.
281 */
282 Packet process( Packet request);
283
284 /**
285 * Invoked before the last copy of the pipeline is about to be discarded,
286 * to give {@link Pipe}s a chance to clean up any resources.
287 *
288 * <p>
289 * This can be used to invoke {@link PreDestroy} lifecycle methods
290 * on user handler. The invocation of it is optional on the client side,
291 * but mandatory on the server side.
292 *
293 * <p>
294 * When multiple copies of pipelines are created, this method is called
295 * only on one of them.
296 *
297 * @throws WebServiceException
298 * If the clean up fails, {@link WebServiceException} can be thrown.
299 * This exception will be propagated to users (if this is client),
300 * or recorded (if this is server.)
301 */
302 void preDestroy();
303
304 /**
305 * Creates an identical clone of this {@link Pipe}.
306 *
307 * <p>
308 * This method creates an identical pipeline that can be used
309 * concurrently with this pipeline. When the caller of a pipeline
310 * is multi-threaded and need concurrent use of the same pipeline,
311 * it can do so by creating copies through this method.
312 *
313 * <h3>Implementation Note</h3>
314 * <p>
315 * It is the implementation's responsibility to call
316 * {@link PipeCloner#add(Pipe,Pipe)} to register the copied pipe
317 * with the original. This is required before you start copying
318 * the other {@link Pipe} references you have, or else there's a
319 * risk of infinite recursion.
320 * <p>
321 * For most {@link Pipe} implementations that delegate to another
322 * {@link Pipe}, this method requires that you also copy the {@link Pipe}
323 * that you delegate to.
324 * <p>
325 * For limited number of {@link Pipe}s that do not maintain any
326 * thread unsafe resource, it is allowed to simply return <tt>this</tt>
327 * from this method (notice that even if you are stateless, if you
328 * got a delegating {@link Pipe} and that one isn't stateless, you
329 * still have to copy yourself.)
330 *
331 * <p>
332 * Note that this method might be invoked by one thread while another
333 * thread is executing the {@link #process(Packet)} method. See
334 * the {@link Codec#copy()} for more discussion about this.
335 *
336 * @param cloner
337 * Use this object (in particular its {@link PipeCloner#copy(Pipe)} method
338 * to clone other pipe references you have
339 * in your pipe. See {@link PipeCloner} for more discussion
340 * about why.
341 *
342 * @return
343 * always non-null {@link Pipe}.
344 */
345 Pipe copy(PipeCloner cloner);
346 }