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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.
What is a Tube?
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 Packets in a sequential fashion.
Tubes run asynchronously. That is, there is no guarantee that processRequest(Packet) and 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.)
Tube examples
Transport is a kind of tube. It sends the Packet through, say, HTTP connection, and receives the data back into another Packet.
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.
For example, XWSS will be a Tube. It will act on a request Packet, then perhaps wrap it into another Packet to encrypt the body and add a header, then the processing will go on to the next tube.
Yet another kind of filter tube is those that wraps LogicalHandler and 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.
There would be a Tube implementation that invokes Provider. There would be a Tube implementation that invokes a service method on the user's code. There would be a Dispatch implementation that invokes a Tube.
WS-MEX can be implemented as a Tube that looks for Message.getPayloadNamespaceURI() and serves the request.
Tube Lifecycle
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.
Where a need arises to process multiple requests concurrently, a pipeline gets cloned through 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.)
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.)
Before a pipeline owner dies, it may invoke 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.
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.
Tube and state
The lifecycle of pipelines is designed to allow a Tube to store various state in easily accessible fashion.
Per-packet state
Any information that changes from a packet to packet should be stored in Packet (if such informaton is specific to your problem domain, then most likely Packet.invocationProperties.) This includes information like transport-specific headers.
Per-thread state
Any expensive-to-create objects that are non-reentrant can be stored either in instance variables of a Tube, or a static ThreadLocal.
The first approach works, because Tube is non reentrant. When a tube is copied, new instances should be allocated so that two Tube instances don't share thread-unsafe resources. Similarly the second approach works, since ThreadLocal guarantees that each thread gets its own private copy.
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.
This includes state like canonicalizers, JAXB unmarshallers, SimpleDateFormat, etc.
Per-proxy/per-endpoint state
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:
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);
}
}
Note that access to such resource may need to be synchronized,
since multiple copies of pipelines may execute concurrently.
VM-wide state
static is always there for you to use.
Author: Kohsuke Kawaguchi, Jitendra Kotamraju See Also:
/**
* 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>
* {@code static} 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
Params: - request – The packet that represents a request message. If the packet has a non-null message, it must be a valid unconsumed
Message. This message represents the SOAP message to be sent as a request.
The packet is also allowed to carry no message, which indicates
that this is an output-only request.
(that's called "solicit", right? - KK)
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
Adapter if it's one-way.) This frees each Tube from try/catching a WebServiceException in every layer. Note that this method is also allowed to return NextAction.returnWith(Packet) with a Packet that has a fault as the payload. On the client side, the 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 Tube, you must not eat the exception that was given to processException(Throwable) .
- 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.)
On the server side, this exception should be most likely
just logged. On the client-side it gets propagated to the
client application.
The consequence of this is that if a pipe calls into an user application (such as SOAPHandler or LogicalHandler), where a RuntimeException is *not* a bug in the JAX-WS implementation, it must be catched and wrapped into a WebServiceException.
Returns: A NextAction object that represents the next action to be taken by the JAX-WS runtime.
/**
* 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.
Once a processRequest(Packet) is invoked, this method will be always invoked with the response, before this Tube processes another request.
Params: - response – If the packet has a non-null message, it must be a valid unconsumed
Message. This message represents a response to the request message passed to processRequest(Packet) earlier.
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
Returns: A NextAction object that represents the next action to be taken by the JAX-WS runtime.
/**
* 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.
If a processRequest(Packet), processResponse(Packet), processException(Throwable) throws an exception, this method will be always invoked on all the Tubes in the remaining NextActions.
On the server side, the 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 Tube like AbstractTubeImpl, you don't have to override the implementation). On the other hand, any intermediate Tube may want to convert the exception to a fault message.
On the client side, the 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 Tube like AbstractTubeImpl, you don't have to override the implementation)
Params: - t –
Returns: A NextAction object that represents the next action to be taken by the JAX-WS runtime.
/**
* 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 Tubes a chance to clean up any resources. This can be used to invoke PreDestroy lifecycle methods on user handler. The invocation of it is optional on the client side, but mandatory on the server side.
When multiple copies of pipelines are created, this method is called
only on one of them.
Throws: - WebServiceException – If the clean up fails,
WebServiceException can be thrown. This exception will be propagated to users (if this is client), or recorded (if this is server.)
/**
* 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 Tube.
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.
Implementation Note
It is the implementation's responsibility to call TubeCloner.add(Tube, Tube) to register the copied pipe with the original. This is required before you start copying the other Tube references you have, or else there's a risk of infinite recursion.
For most Tube implementations that delegate to another Tube, this method requires that you also copy the Tube that you delegate to.
For limited number of Tubes that do not maintain any thread unsafe resource, it is allowed to simply return this from this method (notice that even if you are stateless, if you got a delegating Tube and that one isn't stateless, you still have to copy yourself.)
Note that this method might be invoked by one thread while another thread is executing the other process method. See the Codec.copy() for more discussion about this.
Params: - cloner – Use this object (in particular its
TubeCloner.copy(Tube) method to clone other pipe references you have in your pipe. See TubeCloner for more discussion about why.
Returns: always non-null Tube.
/**
* 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 {@code this}
* 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);
}