jaxws/src/share/classes/com/sun/xml/internal/ws/server/StatefulInstanceResolver.java - platform/libcore - Git at Google

 /*
  * Copyright 2005-2006 Sun Microsystems, Inc.  All Rights Reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
  * under the terms of the GNU General Public License version 2 only, as
  * published by the Free Software Foundation.  Sun designates this
  * particular file as subject to the "Classpath" exception as provided
  * by Sun in the LICENSE file that accompanied this code.
  *
  * This code is distributed in the hope that it will be useful, but WITHOUT
  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  * version 2 for more details (a copy is included in the LICENSE file that
  * accompanied this code).
  *
  * You should have received a copy of the GNU General Public License version
  * 2 along with this work; if not, write to the Free Software Foundation,
  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
  *
  * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
  * CA 95054 USA or visit www.sun.com if you need additional information or
  * have any questions.
  */

 package com.sun.xml.internal.ws.server;

 import com.sun.istack.internal.FragmentContentHandler;
 import com.sun.istack.internal.NotNull;
 import com.sun.istack.internal.Nullable;
 import com.sun.xml.internal.stream.buffer.XMLStreamBufferSource;
 import com.sun.xml.internal.stream.buffer.stax.StreamWriterBufferCreator;
 import com.sun.xml.internal.ws.api.addressing.AddressingVersion;
 import com.sun.xml.internal.ws.api.message.Header;
 import com.sun.xml.internal.ws.api.message.HeaderList;
 import com.sun.xml.internal.ws.api.message.Packet;
 import com.sun.xml.internal.ws.api.server.InstanceResolver;
 import com.sun.xml.internal.ws.api.server.WSEndpoint;
 import com.sun.xml.internal.ws.api.server.WSWebServiceContext;
 import com.sun.xml.internal.ws.developer.EPRRecipe;
 import com.sun.xml.internal.ws.developer.StatefulWebServiceManager;
 import com.sun.xml.internal.ws.resources.ServerMessages;
 import com.sun.xml.internal.ws.spi.ProviderImpl;
 import com.sun.xml.internal.ws.util.xml.ContentHandlerToXMLStreamWriter;
 import com.sun.xml.internal.ws.util.xml.XmlUtil;
 import org.xml.sax.Attributes;
 import org.xml.sax.SAXException;
 import org.xml.sax.helpers.DefaultHandler;

 import javax.xml.namespace.QName;
 import javax.xml.stream.XMLStreamException;
 import javax.xml.transform.Source;
 import javax.xml.transform.Transformer;
 import javax.xml.transform.TransformerException;
 import javax.xml.transform.sax.SAXResult;
 import javax.xml.ws.EndpointReference;
 import javax.xml.ws.WebServiceContext;
 import javax.xml.ws.WebServiceException;
 import javax.xml.ws.wsaddressing.W3CEndpointReference;
 import java.lang.reflect.Field;
 import java.lang.reflect.Method;
 import java.lang.reflect.Modifier;
 import java.util.Collections;
 import java.util.HashMap;
 import java.util.List;
 import java.util.Map;
 import java.util.Timer;
 import java.util.TimerTask;
 import java.util.UUID;
 import java.util.logging.Level;
 import java.util.logging.Logger;

 /**
  * {@link InstanceResolver} that looks at JAX-WS cookie header to
  * determine the instance to which a message will be routed.
  *
  * <p>
  * See {@link StatefulWebServiceManager} for more about user-level semantics.
  *
  * @author Kohsuke Kawaguchi
  */
 public final class StatefulInstanceResolver<T> extends AbstractMultiInstanceResolver<T> implements StatefulWebServiceManager<T> {
     /**
      * This instance is used for serving messages that have no cookie
      * or cookie value that the server doesn't recognize.
      */
     private volatile @Nullable T fallback;

     /**
      * Maintains the stateful service instance and its time-out timer.
      */
     private final class Instance {
         final @NotNull T instance;
         TimerTask task;

         public Instance(T instance) {
             this.instance = instance;
         }

         /**
          * Resets the timer.
          */
         public synchronized void restartTimer() {
             cancel();
             if(timeoutMilliseconds==0)  return; // no timer

             task = new TimerTask() {
                 public void run() {
                     try {
                         Callback<T> cb = timeoutCallback;
                         if(cb!=null) {
                             cb.onTimeout(instance,StatefulInstanceResolver.this);
                             return;
                         }
                         // default operation is to unexport it.
                         unexport(instance);
                     } catch (Throwable e) {
                         // don't let an error in the code kill the timer thread
                         logger.log(Level.SEVERE, "time out handler failed", e);
                     }
                 }
             };
             timer.schedule(task,timeoutMilliseconds);
         }

         /**
          * Cancels the timer.
          */
         public synchronized void cancel() {
             if(task!=null)
                 task.cancel();
             task = null;
         }
     }

     /**
      * Maps object ID to instances.
      */
     private final Map<String,Instance> instances = Collections.synchronizedMap(new HashMap<String,Instance>());
     /**
      * Reverse look up for {@link #instances}.
      */
     private final Map<T,String> reverseInstances = Collections.synchronizedMap(new HashMap<T,String>());

     // time out control. 0=disabled
     private volatile long timeoutMilliseconds = 0;
     private volatile Callback<T> timeoutCallback;

     public StatefulInstanceResolver(Class<T> clazz) {
         super(clazz);
     }

     @Override
     public @NotNull T resolve(Packet request) {
         HeaderList headers = request.getMessage().getHeaders();
         Header header = headers.get(COOKIE_TAG, true);
         String id=null;
         if(header!=null) {
             // find the instance
             id = header.getStringContent();
             Instance o = instances.get(id);
             if(o!=null) {
                 o.restartTimer();
                 return o.instance;
             }

             // huh? what is this ID?
             logger.log(Level.INFO,"Request had an unrecognized object ID "+id);
         }

         // need to fallback
         T fallback = this.fallback;
         if(fallback!=null)
             return fallback;

         if(id==null)
             throw new WebServiceException(ServerMessages.STATEFUL_COOKIE_HEADER_REQUIRED(COOKIE_TAG));
         else
             throw new WebServiceException(ServerMessages.STATEFUL_COOKIE_HEADER_INCORRECT(COOKIE_TAG,id));
     }

     @Override
     public void start(WSWebServiceContext wsc, WSEndpoint endpoint) {
         super.start(wsc,endpoint);

         if(endpoint.getBinding().getAddressingVersion()==null)
             // addressing is not enabled.
             throw new WebServiceException(ServerMessages.STATEFUL_REQURES_ADDRESSING(clazz));

             // inject StatefulWebServiceManager.
         for(Field field: clazz.getDeclaredFields()) {
             if(field.getType()==StatefulWebServiceManager.class) {
                 if(!Modifier.isStatic(field.getModifiers()))
                     throw new WebServiceException(ServerMessages.STATIC_RESOURCE_INJECTION_ONLY(StatefulWebServiceManager.class,field));
                 new FieldInjectionPlan<T,StatefulWebServiceManager>(field).inject(null,this);
             }
         }

         for(Method method : clazz.getDeclaredMethods()) {
             Class[] paramTypes = method.getParameterTypes();
             if (paramTypes.length != 1)
                 continue;   // not what we are looking for

             if(paramTypes[0]==StatefulWebServiceManager.class) {
                 if(!Modifier.isStatic(method.getModifiers()))
                     throw new WebServiceException(ServerMessages.STATIC_RESOURCE_INJECTION_ONLY(StatefulWebServiceManager.class,method));

                 new MethodInjectionPlan<T,StatefulWebServiceManager>(method).inject(null,this);
             }
         }
     }

     @Override
     public void dispose() {
         reverseInstances.clear();
         synchronized(instances) {
             for (Instance t : instances.values()) {
                 t.cancel();
                 dispose(t.instance);
             }
             instances.clear();
         }
         if(fallback!=null)
             dispose(fallback);
         fallback = null;
     }

     @NotNull
     public W3CEndpointReference export(T o) {
         return export(W3CEndpointReference.class,o);
     }

     @NotNull
     public <EPR extends EndpointReference>EPR export(Class<EPR> epr, T o) {
         return export(epr,o,null);
     }

     public <EPR extends EndpointReference> EPR export(Class<EPR> epr, T o, EPRRecipe recipe) {
         return export(epr, InvokerTube.getCurrentPacket(), o, recipe);
     }

     @NotNull
     public <EPR extends EndpointReference>EPR export(Class<EPR> epr, WebServiceContext context, T o) {
         if (context instanceof WSWebServiceContext) {
             WSWebServiceContext wswsc = (WSWebServiceContext) context;
             return export(epr, wswsc.getRequestPacket(), o);
         }

         throw new WebServiceException(ServerMessages.STATEFUL_INVALID_WEBSERVICE_CONTEXT(context));
     }

     @NotNull
     public <EPR extends EndpointReference> EPR export(Class<EPR> adrsVer, @NotNull Packet currentRequest, T o) {
         return export(adrsVer,currentRequest,o,null);
     }

     public <EPR extends EndpointReference> EPR export(Class<EPR> adrsVer, @NotNull Packet currentRequest, T o, EPRRecipe recipe) {
         return export(adrsVer, currentRequest.webServiceContextDelegate.getEPRAddress(currentRequest,owner), o, recipe);
     }

     @NotNull
     public <EPR extends EndpointReference> EPR export(Class<EPR> adrsVer, String endpointAddress, T o) {
         return export(adrsVer,endpointAddress,o,null);
     }

     @NotNull
     public <EPR extends EndpointReference> EPR export(Class<EPR> adrsVer, String endpointAddress, T o, EPRRecipe recipe) {
         if(endpointAddress==null)
             throw new IllegalArgumentException("No address available");

         String key = reverseInstances.get(o);

         if(key!=null) return createEPR(key, adrsVer, endpointAddress, recipe);

         // not exported yet.
         synchronized(this) {
             // double check now in the synchronization block to
             // really make sure that we can export.
             key = reverseInstances.get(o);
             if(key!=null) return createEPR(key, adrsVer, endpointAddress, recipe);

             if(o!=null)
                 prepare(o);
             key = UUID.randomUUID().toString();
             Instance instance = new Instance(o);
             instances.put(key, instance);
             reverseInstances.put(o,key);
             if(timeoutMilliseconds!=0)
                 instance.restartTimer();
         }

         return createEPR(key, adrsVer, endpointAddress, recipe);
     }

     /**
      * Creates an EPR that has the right key.
      */
     private <EPR extends EndpointReference> EPR createEPR(String key, Class<EPR> eprClass, String address, EPRRecipe recipe) {
         AddressingVersion adrsVer = AddressingVersion.fromSpecClass(eprClass);

         try {
             StreamWriterBufferCreator w = new StreamWriterBufferCreator();

             w.writeStartDocument();
             w.writeStartElement("wsa","EndpointReference", adrsVer.nsUri);
             w.writeNamespace("wsa",adrsVer.nsUri);

             w.writeStartElement("wsa","Address",adrsVer.nsUri);
             w.writeCharacters(address);
             w.writeEndElement();

             w.writeStartElement("wsa","ReferenceParameters",adrsVer.nsUri);
             w.writeStartElement(COOKIE_TAG.getPrefix(), COOKIE_TAG.getLocalPart(), COOKIE_TAG.getNamespaceURI());
             w.writeCharacters(key);
             w.writeEndElement();
             if(recipe!=null) {
                 for (Header h : recipe.getReferenceParameters())
                     h.writeTo(w);
             }
             w.writeEndElement();

             if(recipe!=null) {
                 List<Source> metadata = recipe.getMetadata();
                 if(!metadata.isEmpty()) {
                     w.writeStartElement("wsa","Metadata",adrsVer.nsUri);
                     Transformer t = XmlUtil.newTransformer();
                     for (Source s : metadata)
                         try {
                             t.transform(s,
                                 new SAXResult(new FragmentContentHandler(new ContentHandlerToXMLStreamWriter(w))));
                         } catch (TransformerException e) {
                             throw new IllegalArgumentException("Unable to write EPR metadata "+s,e);
                         }
                     w.writeEndElement();
                 }
             }

             w.writeEndElement();
             w.writeEndDocument();

             // TODO: this can be done better by writing SAX code that produces infoset
             // and setting that as Source.
             return eprClass.cast(ProviderImpl.INSTANCE.readEndpointReference(
                 new XMLStreamBufferSource(w.getXMLStreamBuffer())));
         } catch (XMLStreamException e) {
             throw new Error(e); // this must be a bug in our code
         }
     }

     public void unexport(@Nullable T o) {
         if(o==null)     return;
         String key = reverseInstances.get(o);
         if(key==null)   return; // already unexported
         instances.remove(key);
     }

     public T resolve(EndpointReference epr) {
         class CookieSniffer extends DefaultHandler {
             StringBuilder buf = new StringBuilder();
             boolean inCookie = false;
             public void startElement(String uri, String localName, String qName, Attributes attributes) throws SAXException {
                 if(localName.equals(COOKIE_TAG.getLocalPart()) && uri.equals(COOKIE_TAG.getNamespaceURI()))
                     inCookie = true;
             }
             public void characters(char ch[], int start, int length) throws SAXException {
                 if(inCookie)
                     buf.append(ch,start,length);
             }
             public void endElement(String uri, String localName, String qName) throws SAXException {
                 inCookie = false;
             }
         }
         CookieSniffer sniffer = new CookieSniffer();
         epr.writeTo(new SAXResult(sniffer));

         Instance o = instances.get(sniffer.buf.toString());
         if(o!=null)
             return o.instance;
         return null;
     }

     public void setFallbackInstance(T o) {
         if(o!=null)
             prepare(o);
         this.fallback = o;
     }

     public void setTimeout(long milliseconds, Callback<T> callback) {
         if(milliseconds<0)
             throw new IllegalArgumentException();
         this.timeoutMilliseconds = milliseconds;
         this.timeoutCallback = callback;
         if(timeoutMilliseconds>0)
             startTimer();
     }

     public void touch(T o) {
         String key = reverseInstances.get(o);
         if(key==null)   return; // already unexported.
         Instance inst = instances.get(key);
         if(inst==null)  return;
         inst.restartTimer();
     }

     /**
      * Timer that controls the instance time out. Lazily created.
      */
     private static volatile Timer timer;

     private static synchronized void startTimer() {
         if(timer==null)
             timer = new Timer("JAX-WS stateful web service timeout timer");
     }


     private static final QName COOKIE_TAG = new QName("http://jax-ws.dev.java.net/xml/ns/","objectId","jaxws");

     private static final Logger logger =
         Logger.getLogger(com.sun.xml.internal.ws.util.Constants.LoggingDomain + ".server");
 }
	/*
	* Copyright 2005-2006 Sun Microsystems, Inc. All Rights Reserved.
	* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
	*
	* This code is free software; you can redistribute it and/or modify it
	* under the terms of the GNU General Public License version 2 only, as
	* published by the Free Software Foundation. Sun designates this
	* particular file as subject to the "Classpath" exception as provided
	* by Sun in the LICENSE file that accompanied this code.
	*
	* This code is distributed in the hope that it will be useful, but WITHOUT
	* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
	* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
	* version 2 for more details (a copy is included in the LICENSE file that
	* accompanied this code).
	*
	* You should have received a copy of the GNU General Public License version
	* 2 along with this work; if not, write to the Free Software Foundation,
	* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
	*
	* Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
	* CA 95054 USA or visit www.sun.com if you need additional information or
	* have any questions.
	*/

	package com.sun.xml.internal.ws.server;

	import com.sun.istack.internal.FragmentContentHandler;
	import com.sun.istack.internal.NotNull;
	import com.sun.istack.internal.Nullable;
	import com.sun.xml.internal.stream.buffer.XMLStreamBufferSource;
	import com.sun.xml.internal.stream.buffer.stax.StreamWriterBufferCreator;
	import com.sun.xml.internal.ws.api.addressing.AddressingVersion;
	import com.sun.xml.internal.ws.api.message.Header;
	import com.sun.xml.internal.ws.api.message.HeaderList;
	import com.sun.xml.internal.ws.api.message.Packet;
	import com.sun.xml.internal.ws.api.server.InstanceResolver;
	import com.sun.xml.internal.ws.api.server.WSEndpoint;
	import com.sun.xml.internal.ws.api.server.WSWebServiceContext;
	import com.sun.xml.internal.ws.developer.EPRRecipe;
	import com.sun.xml.internal.ws.developer.StatefulWebServiceManager;
	import com.sun.xml.internal.ws.resources.ServerMessages;
	import com.sun.xml.internal.ws.spi.ProviderImpl;
	import com.sun.xml.internal.ws.util.xml.ContentHandlerToXMLStreamWriter;
	import com.sun.xml.internal.ws.util.xml.XmlUtil;
	import org.xml.sax.Attributes;
	import org.xml.sax.SAXException;
	import org.xml.sax.helpers.DefaultHandler;

	import javax.xml.namespace.QName;
	import javax.xml.stream.XMLStreamException;
	import javax.xml.transform.Source;
	import javax.xml.transform.Transformer;
	import javax.xml.transform.TransformerException;
	import javax.xml.transform.sax.SAXResult;
	import javax.xml.ws.EndpointReference;
	import javax.xml.ws.WebServiceContext;
	import javax.xml.ws.WebServiceException;
	import javax.xml.ws.wsaddressing.W3CEndpointReference;
	import java.lang.reflect.Field;
	import java.lang.reflect.Method;
	import java.lang.reflect.Modifier;
	import java.util.Collections;
	import java.util.HashMap;
	import java.util.List;
	import java.util.Map;
	import java.util.Timer;
	import java.util.TimerTask;
	import java.util.UUID;
	import java.util.logging.Level;
	import java.util.logging.Logger;

	/**
	* {@link InstanceResolver} that looks at JAX-WS cookie header to
	* determine the instance to which a message will be routed.
	*
	* <p>
	* See {@link StatefulWebServiceManager} for more about user-level semantics.
	*
	* @author Kohsuke Kawaguchi
	*/
	public final class StatefulInstanceResolver<T> extends AbstractMultiInstanceResolver<T> implements StatefulWebServiceManager<T> {
	/**
	* This instance is used for serving messages that have no cookie
	* or cookie value that the server doesn't recognize.
	*/
	private volatile @Nullable T fallback;

	/**
	* Maintains the stateful service instance and its time-out timer.
	*/
	private final class Instance {
	final @NotNull T instance;
	TimerTask task;

	public Instance(T instance) {
	this.instance = instance;
	}

	/**
	* Resets the timer.
	*/
	public synchronized void restartTimer() {
	cancel();
	if(timeoutMilliseconds==0) return; // no timer

	task = new TimerTask() {
	public void run() {
	try {
	Callback<T> cb = timeoutCallback;
	if(cb!=null) {
	cb.onTimeout(instance,StatefulInstanceResolver.this);
	return;
	}
	// default operation is to unexport it.
	unexport(instance);
	} catch (Throwable e) {
	// don't let an error in the code kill the timer thread
	logger.log(Level.SEVERE, "time out handler failed", e);
	}
	}
	};
	timer.schedule(task,timeoutMilliseconds);
	}

	/**
	* Cancels the timer.
	*/
	public synchronized void cancel() {
	if(task!=null)
	task.cancel();
	task = null;
	}
	}

	/**
	* Maps object ID to instances.
	*/
	private final Map<String,Instance> instances = Collections.synchronizedMap(new HashMap<String,Instance>());
	/**
	* Reverse look up for {@link #instances}.
	*/
	private final Map<T,String> reverseInstances = Collections.synchronizedMap(new HashMap<T,String>());

	// time out control. 0=disabled
	private volatile long timeoutMilliseconds = 0;
	private volatile Callback<T> timeoutCallback;

	public StatefulInstanceResolver(Class<T> clazz) {
	super(clazz);
	}

	@Override
	public @NotNull T resolve(Packet request) {
	HeaderList headers = request.getMessage().getHeaders();
	Header header = headers.get(COOKIE_TAG, true);
	String id=null;
	if(header!=null) {
	// find the instance
	id = header.getStringContent();
	Instance o = instances.get(id);
	if(o!=null) {
	o.restartTimer();
	return o.instance;
	}

	// huh? what is this ID?
	logger.log(Level.INFO,"Request had an unrecognized object ID "+id);
	}

	// need to fallback
	T fallback = this.fallback;
	if(fallback!=null)
	return fallback;

	if(id==null)
	throw new WebServiceException(ServerMessages.STATEFUL_COOKIE_HEADER_REQUIRED(COOKIE_TAG));
	else
	throw new WebServiceException(ServerMessages.STATEFUL_COOKIE_HEADER_INCORRECT(COOKIE_TAG,id));
	}

	@Override
	public void start(WSWebServiceContext wsc, WSEndpoint endpoint) {
	super.start(wsc,endpoint);

	if(endpoint.getBinding().getAddressingVersion()==null)
	// addressing is not enabled.
	throw new WebServiceException(ServerMessages.STATEFUL_REQURES_ADDRESSING(clazz));

	// inject StatefulWebServiceManager.
	for(Field field: clazz.getDeclaredFields()) {
	if(field.getType()==StatefulWebServiceManager.class) {
	if(!Modifier.isStatic(field.getModifiers()))
	throw new WebServiceException(ServerMessages.STATIC_RESOURCE_INJECTION_ONLY(StatefulWebServiceManager.class,field));
	new FieldInjectionPlan<T,StatefulWebServiceManager>(field).inject(null,this);
	}
	}

	for(Method method : clazz.getDeclaredMethods()) {
	Class[] paramTypes = method.getParameterTypes();
	if (paramTypes.length != 1)
	continue; // not what we are looking for

	if(paramTypes[0]==StatefulWebServiceManager.class) {
	if(!Modifier.isStatic(method.getModifiers()))
	throw new WebServiceException(ServerMessages.STATIC_RESOURCE_INJECTION_ONLY(StatefulWebServiceManager.class,method));

	new MethodInjectionPlan<T,StatefulWebServiceManager>(method).inject(null,this);
	}
	}
	}

	@Override
	public void dispose() {
	reverseInstances.clear();
	synchronized(instances) {
	for (Instance t : instances.values()) {
	t.cancel();
	dispose(t.instance);
	}
	instances.clear();
	}
	if(fallback!=null)
	dispose(fallback);
	fallback = null;
	}

	@NotNull
	public W3CEndpointReference export(T o) {
	return export(W3CEndpointReference.class,o);
	}

	@NotNull
	public <EPR extends EndpointReference>EPR export(Class<EPR> epr, T o) {
	return export(epr,o,null);
	}

	public <EPR extends EndpointReference> EPR export(Class<EPR> epr, T o, EPRRecipe recipe) {
	return export(epr, InvokerTube.getCurrentPacket(), o, recipe);
	}

	@NotNull
	public <EPR extends EndpointReference>EPR export(Class<EPR> epr, WebServiceContext context, T o) {
	if (context instanceof WSWebServiceContext) {
	WSWebServiceContext wswsc = (WSWebServiceContext) context;
	return export(epr, wswsc.getRequestPacket(), o);
	}

	throw new WebServiceException(ServerMessages.STATEFUL_INVALID_WEBSERVICE_CONTEXT(context));
	}

	@NotNull
	public <EPR extends EndpointReference> EPR export(Class<EPR> adrsVer, @NotNull Packet currentRequest, T o) {
	return export(adrsVer,currentRequest,o,null);
	}

	public <EPR extends EndpointReference> EPR export(Class<EPR> adrsVer, @NotNull Packet currentRequest, T o, EPRRecipe recipe) {
	return export(adrsVer, currentRequest.webServiceContextDelegate.getEPRAddress(currentRequest,owner), o, recipe);
	}

	@NotNull
	public <EPR extends EndpointReference> EPR export(Class<EPR> adrsVer, String endpointAddress, T o) {
	return export(adrsVer,endpointAddress,o,null);
	}

	@NotNull
	public <EPR extends EndpointReference> EPR export(Class<EPR> adrsVer, String endpointAddress, T o, EPRRecipe recipe) {
	if(endpointAddress==null)
	throw new IllegalArgumentException("No address available");

	String key = reverseInstances.get(o);

	if(key!=null) return createEPR(key, adrsVer, endpointAddress, recipe);

	// not exported yet.
	synchronized(this) {
	// double check now in the synchronization block to
	// really make sure that we can export.
	key = reverseInstances.get(o);
	if(key!=null) return createEPR(key, adrsVer, endpointAddress, recipe);

	if(o!=null)
	prepare(o);
	key = UUID.randomUUID().toString();
	Instance instance = new Instance(o);
	instances.put(key, instance);
	reverseInstances.put(o,key);
	if(timeoutMilliseconds!=0)
	instance.restartTimer();
	}

	return createEPR(key, adrsVer, endpointAddress, recipe);
	}

	/**
	* Creates an EPR that has the right key.
	*/
	private <EPR extends EndpointReference> EPR createEPR(String key, Class<EPR> eprClass, String address, EPRRecipe recipe) {
	AddressingVersion adrsVer = AddressingVersion.fromSpecClass(eprClass);

	try {
	StreamWriterBufferCreator w = new StreamWriterBufferCreator();

	w.writeStartDocument();
	w.writeStartElement("wsa","EndpointReference", adrsVer.nsUri);
	w.writeNamespace("wsa",adrsVer.nsUri);

	w.writeStartElement("wsa","Address",adrsVer.nsUri);
	w.writeCharacters(address);
	w.writeEndElement();

	w.writeStartElement("wsa","ReferenceParameters",adrsVer.nsUri);
	w.writeStartElement(COOKIE_TAG.getPrefix(), COOKIE_TAG.getLocalPart(), COOKIE_TAG.getNamespaceURI());
	w.writeCharacters(key);
	w.writeEndElement();
	if(recipe!=null) {
	for (Header h : recipe.getReferenceParameters())
	h.writeTo(w);
	}
	w.writeEndElement();

	if(recipe!=null) {
	List<Source> metadata = recipe.getMetadata();
	if(!metadata.isEmpty()) {
	w.writeStartElement("wsa","Metadata",adrsVer.nsUri);
	Transformer t = XmlUtil.newTransformer();
	for (Source s : metadata)
	try {
	t.transform(s,
	new SAXResult(new FragmentContentHandler(new ContentHandlerToXMLStreamWriter(w))));
	} catch (TransformerException e) {
	throw new IllegalArgumentException("Unable to write EPR metadata "+s,e);
	}
	w.writeEndElement();
	}
	}

	w.writeEndElement();
	w.writeEndDocument();

	// TODO: this can be done better by writing SAX code that produces infoset
	// and setting that as Source.
	return eprClass.cast(ProviderImpl.INSTANCE.readEndpointReference(
	new XMLStreamBufferSource(w.getXMLStreamBuffer())));
	} catch (XMLStreamException e) {
	throw new Error(e); // this must be a bug in our code
	}
	}

	public void unexport(@Nullable T o) {
	if(o==null) return;
	String key = reverseInstances.get(o);
	if(key==null) return; // already unexported
	instances.remove(key);
	}

	public T resolve(EndpointReference epr) {
	class CookieSniffer extends DefaultHandler {
	StringBuilder buf = new StringBuilder();
	boolean inCookie = false;
	public void startElement(String uri, String localName, String qName, Attributes attributes) throws SAXException {
	if(localName.equals(COOKIE_TAG.getLocalPart()) && uri.equals(COOKIE_TAG.getNamespaceURI()))
	inCookie = true;
	}
	public void characters(char ch[], int start, int length) throws SAXException {
	if(inCookie)
	buf.append(ch,start,length);
	}
	public void endElement(String uri, String localName, String qName) throws SAXException {
	inCookie = false;
	}
	}
	CookieSniffer sniffer = new CookieSniffer();
	epr.writeTo(new SAXResult(sniffer));

	Instance o = instances.get(sniffer.buf.toString());
	if(o!=null)
	return o.instance;
	return null;
	}

	public void setFallbackInstance(T o) {
	if(o!=null)
	prepare(o);
	this.fallback = o;
	}

	public void setTimeout(long milliseconds, Callback<T> callback) {
	if(milliseconds<0)
	throw new IllegalArgumentException();
	this.timeoutMilliseconds = milliseconds;
	this.timeoutCallback = callback;
	if(timeoutMilliseconds>0)
	startTimer();
	}

	public void touch(T o) {
	String key = reverseInstances.get(o);
	if(key==null) return; // already unexported.
	Instance inst = instances.get(key);
	if(inst==null) return;
	inst.restartTimer();
	}

	/**
	* Timer that controls the instance time out. Lazily created.
	*/
	private static volatile Timer timer;

	private static synchronized void startTimer() {
	if(timer==null)
	timer = new Timer("JAX-WS stateful web service timeout timer");
	}


	private static final QName COOKIE_TAG = new QName("http://jax-ws.dev.java.net/xml/ns/","objectId","jaxws");

	private static final Logger logger =
	Logger.getLogger(com.sun.xml.internal.ws.util.Constants.LoggingDomain + ".server");
	}