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 package com.sun.xml.internal.ws.api.pipe;

 import com.sun.istack.internal.NotNull;

 import com.sun.xml.internal.ws.api.message.Message;

 import com.sun.xml.internal.ws.api.message.Packet;

 import com.sun.xml.internal.ws.api.pipe.helper.AbstractFilterTubeImpl;

 import com.sun.xml.internal.ws.api.pipe.helper.AbstractTubeImpl;

 import com.sun.xml.internal.ws.api.server.Adapter;

 import javax.annotation.PreDestroy;

 import javax.xml.ws.Dispatch;

 import javax.xml.ws.Provider;

 import javax.xml.ws.WebServiceException;

 import javax.xml.ws.handler.LogicalHandler;

 import javax.xml.ws.handler.soap.SOAPHandler;

 import java.text.SimpleDateFormat;

 /**

  * Abstraction of the intermediate layers in the processing chain

  * and transport.

  *

  * <h2>What is a {@link Tube}?</h2>

  * <p>

  * {@link Tube} is a basic processing unit that represents SOAP-level

  * protocol handling code. Mutliple tubes are often put together in

  * a line (it needs not one dimensional — more later), and act on

  * {@link Packet}s in a sequential fashion.

  *

  * <p>

  * {@link Tube}s run asynchronously. That is, there is no guarantee that

  * {@link #processRequest(Packet)} and {@link #processResponse(Packet)} runs

  * in the same thread, nor is there any guarantee that this tube and next

  * tube runs in the same thread. Furthermore, one thread may be used to

  * run multiple pipeline in turn (just like a real CPU runs multiple

  * threads in turn.)

  *

  *

  * <h2>Tube examples</h2>

  * <p>

  * Transport is a kind of tube. It sends the {@link Packet}

  * through, say, HTTP connection, and receives the data back into another {@link Packet}.

  *

  * <p>

  * More often, a tube works like a filter. It acts on a packet,

  * and then it tells the JAX-WS that the packet should be passed into another

  * tube. It can do the same on the way back.

  *

  * <p>

  * For example, XWSS will be a {@link Tube}. It will act on a request

  * {@link Packet}, then perhaps wrap it into

  * another {@link Packet} to encrypt the body and add a header, then

  * the processing will go on to the next tube.

  *

  * <p>

  * Yet another kind of filter tube is those that wraps {@link LogicalHandler}

  * and {@link SOAPHandler}. These tubes are heavy-weight; they often consume

  * a message in a packet and create a new one, and then pass it to the next tube.

  *

  * <p>

  * There would be a {@link Tube} implementation that invokes {@link Provider}.

  * There would be a {@link Tube} implementation that invokes a service method

  * on the user's code.

  * There would be a {@link Dispatch} implementation that invokes a {@link Tube}.

  *

  * <p>

  * WS-MEX can be implemented as a {@link Tube} that looks for

  * {@link Message#getPayloadNamespaceURI()} and serves the request.

  *

  *

  *

  *

  * <h2>Tube Lifecycle</h2>

  * Pipeline is expensive to set up, so once it's created it will be reused.

  * A pipeline is not reentrant; one pipeline is used to process one request/response

  * at at time. The same pipeline instance may serve multiple request/response,

  * if one comes after another and they don't overlap.

  * <p>

  * Where a need arises to process multiple requests concurrently, a pipeline

  * gets cloned through {@link TubeCloner}. Note that this need may happen on

  * both server (because it quite often serves multiple requests concurrently)

  * and client (because it needs to support asynchronous method invocations.)

  * <p>

  * Created pipelines (including cloned ones and the original) may be discarded and GC-ed

  * at any time at the discretion of whoever owns pipelines. Tubes can, however, expect

  * at least one copy (or original) of pipeline to live at any given time while a pipeline

  * owner is interested in the given pipeline configuration (in more concerete terms,

  * for example, as long as a dispatch object lives, it's going to keep at least one

  * copy of a pipeline alive.)

  * <p>

  * Before a pipeline owner dies, it may invoke {@link #preDestroy()} on the last

  * remaining pipeline. It is "may" for pipeline owners that live in the client-side

  * of JAX-WS (such as dispatches and proxies), but it is a "must" for pipeline owners

  * that live in the server-side of JAX-WS.

  * <p>

  * This last invocation gives a chance for some pipes to clean up any state/resource

  * acquired (such as WS-RM's sequence, WS-Trust's SecurityToken), although as stated above,

  * this is not required for clients.

  *

  *

  *

  * <h2>Tube and state</h2>

  * <p>

  * The lifecycle of pipelines is designed to allow a {@link Tube} to store various

  * state in easily accessible fashion.

  *

  *

  * <h3>Per-packet state</h3>

  * <p>

  * Any information that changes from a packet to packet should be

  * stored in {@link Packet} (if such informaton is specific to your problem domain,

  * then most likely {@link Packet#invocationProperties}.)

  * This includes information like transport-specific headers.

  *

  * <h3>Per-thread state</h3>

  * <p>

  * Any expensive-to-create objects that are non-reentrant can be stored

  * either in instance variables of a {@link Tube}, or a static {@link ThreadLocal}.

  *

  * <p>

  * The first approach works, because {@link Tube} is

  * non reentrant. When a tube is copied, new instances should be allocated

  * so that two {@link Tube} instances don't share thread-unsafe resources.

  *

  * Similarly the second approach works, since {@link ThreadLocal} guarantees

  * that each thread gets its own private copy.

  *

  * <p>

  * The former is faster to access, and you need not worry about clean up.

  * On the other hand, because there can be many more concurrent requests

  * than # of threads, you may end up holding onto more resources than necessary.

  *

  * <p>

  * This includes state like canonicalizers, JAXB unmarshallers,

  * {@link SimpleDateFormat}, etc.

  *

  *

  * <h3>Per-proxy/per-endpoint state</h3>

  * <p>

  * Information that is tied to a particular proxy/dispatch can be stored

  * in a separate object that is referenced from a tube. When

  * a new tube is copied, you can simply hand out a reference to the newly

  * created one, so that all copied tubes refer to the same instance.

  * See the following code as an example:

  *

  * <pre>

  * class TubeImpl {

  *   // this object stores per-proxy state

  *   class DataStore {

  *     int counter;

  *   }

  *

  *   private DataStore ds;

  *

  *   // create a fresh new pipe

  *   public TubeImpl(...) {

  *     ....

  *     ds = new DataStore();

  *   }

  *

  *   // copy constructor

  *   private TubeImpl(TubeImpl that, PipeCloner cloner) {

  *     cloner.add(that,this);

  *     ...

  *     this.ds = that.ds;

  *   }

  *

  *   public TubeImpl copy(PipeCloner pc) {

  *     return new TubeImpl(this,pc);

  *   }

  * }

  * </pre>

  *

  * <p>

  * Note that access to such resource may need to be synchronized,

  * since multiple copies of pipelines may execute concurrently.

  *

  *

  *

  * <h3>VM-wide state</h3>

  * <p>

  * <tt>static</tt> is always there for you to use.

  *

  *

  *

  * @see AbstractTubeImpl

  * @see AbstractFilterTubeImpl

  *

  * @author Kohsuke Kawaguchi

  * @author Jitendra Kotamraju

  */

 public interface Tube {

     /**

      * Acts on a request and perform some protocol specific operation.

      *

      * TODO: exception handling semantics need more discussion

      *

      * @throws WebServiceException

      *      On the server side, this signals an error condition where

      *      a fault reply is in order (or the exception gets eaten by

      *      the top-most transport {@link Adapter} if it's one-way.)

      *      This frees each {@link Tube} from try/catching a

      *      {@link WebServiceException} in every layer.

      *

      *      Note that this method is also allowed to return

      *      {@link NextAction#returnWith(Packet)} with

      *      a {@link Packet} that has a fault as the payload.

      *

      *      <p>

      *      On the client side, the {@link WebServiceException} thrown

      *      will be propagated all the way back to the calling client

      *      applications. (The consequence of that is that if you are

      *      a filtering {@link Tube}, you must not eat the exception

      *      that was given to {@link #processException(Throwable)} .

      *

      * @throws RuntimeException

      *      Other runtime exception thrown by this method must

      *      be treated as a bug in the tube implementation,

      *      and therefore should not be converted into a fault.

      *      (Otherwise it becomes very difficult to debug implementation

      *      problems.)

      *

      *      <p>

      *      On the server side, this exception should be most likely

      *      just logged. On the client-side it gets propagated to the

      *      client application.

      *

      *      <p>

      *      The consequence of this is that if a pipe calls

      *      into an user application (such as {@link SOAPHandler}

      *      or {@link LogicalHandler}), where a {@link RuntimeException}

      *      is *not* a bug in the JAX-WS implementation, it must be catched

      *      and wrapped into a {@link WebServiceException}.

      *

      * @param request

      *      The packet that represents a request message.

      *      If the packet has a non-null message, it must be a valid

      *      unconsumed {@link Message}. This message represents the

      *      SOAP message to be sent as a request.

      *      <p>

      *      The packet is also allowed to carry no message, which indicates

      *      that this is an output-only request.

      *      (that's called "solicit", right? - KK)

      *

      * @return

      *      A {@link NextAction} object that represents the next action

      *      to be taken by the JAX-WS runtime.

      */

     @NotNull NextAction processRequest(@NotNull Packet request);

     /**

      * Acts on a response and performs some protocol specific operation.

      *

      * <p>

      * Once a {@link #processRequest(Packet)} is invoked, this method

      * will be always invoked with the response, before this {@link Tube}

      * processes another request.

      *

      * @param response

      *      If the packet has a non-null message, it must be

      *      a valid unconsumed {@link Message}. This message represents

      *      a response to the request message passed to

      *      {@link #processRequest(Packet)} earlier.

      *      <p>

      *      The packet is also allowed to carry no message, which indicates

      *      that there was no response. This is used for things like

      *      one-way message and/or one-way transports.

      *

      * TODO: exception handling semantics need more discussion

      *

      * @return

      *      A {@link NextAction} object that represents the next action

      *      to be taken by the JAX-WS runtime.

      */

     @NotNull NextAction processResponse(@NotNull Packet response);

     /**

      * Acts on a exception and performs some clean up operations.

      *

      * <p>

      * If a {@link #processRequest(Packet)}, {@link #processResponse(Packet)},

      * {@link #processException(Throwable)} throws an exception, this method

      * will be always invoked on all the {@link Tube}s in the remaining

      * {@link NextAction}s.

      *

      * <p>

      * On the server side, the {@link Throwable} thrown will be propagated to the

      * top-most transport. The transport converts the exception to fault reply or

      * simply logs in case of one-way MEP. If you are a filtering {@link Tube} like

      * {@link AbstractTubeImpl}, you don't have to override the implementation). On

      * the other hand, any intermediate {@link Tube} may want to convert the exception

      * to a fault message.

      *

      * <p>

      * On the client side, the {@link Throwable} thrown

      * will be propagated all the way back to the calling client

      * applications. (The consequence of that is that if you are

      * a filtering {@link Tube} like {@link AbstractTubeImpl}, you don't have to

      * override the implementation)

      *

      * @param t

      *

      * @return

      *      A {@link NextAction} object that represents the next action

      *      to be taken by the JAX-WS runtime.

      */

     @NotNull NextAction processException(@NotNull Throwable t);

     /**

      * Invoked before the last copy of the pipeline is about to be discarded,

      * to give {@link Tube}s a chance to clean up any resources.

      *

      * <p>

      * This can be used to invoke {@link PreDestroy} lifecycle methods

      * on user handler. The invocation of it is optional on the client side,

      * but mandatory on the server side.

      *

      * <p>

      * When multiple copies of pipelines are created, this method is called

      * only on one of them.

      *

      * @throws WebServiceException

      *      If the clean up fails, {@link WebServiceException} can be thrown.

      *      This exception will be propagated to users (if this is client),

      *      or recorded (if this is server.)

      */

     void preDestroy();

     /**

      * Creates an identical clone of this {@link Tube}.

      *

      * <p>

      * This method creates an identical pipeline that can be used

      * concurrently with this pipeline. When the caller of a pipeline

      * is multi-threaded and need concurrent use of the same pipeline,

      * it can do so by creating copies through this method.

      *

      * <h3>Implementation Note</h3>

      * <p>

      * It is the implementation's responsibility to call

      * {@link TubeCloner#add(Tube,Tube)} to register the copied pipe

      * with the original. This is required before you start copying

      * the other {@link Tube} references you have, or else there's a

      * risk of infinite recursion.

      * <p>

      * For most {@link Tube} implementations that delegate to another

      * {@link Tube}, this method requires that you also copy the {@link Tube}

      * that you delegate to.

      * <p>

      * For limited number of {@link Tube}s that do not maintain any

      * thread unsafe resource, it is allowed to simply return <tt>this</tt>

      * from this method (notice that even if you are stateless, if you

      * got a delegating {@link Tube} and that one isn't stateless, you

      * still have to copy yourself.)

      *

      * <p>

      * Note that this method might be invoked by one thread while another

      * thread is executing the other process method. See

      * the {@link Codec#copy()} for more discussion about this.

      *

      * @param cloner

      *      Use this object (in particular its {@link TubeCloner#copy(Tube)} method

      *      to clone other pipe references you have

      *      in your pipe. See {@link TubeCloner} for more discussion

      *      about why.

      *

      * @return

      *      always non-null {@link Tube}.

      */

     Tube copy(TubeCloner cloner);

 }