/*

  * ============================================================================

  *

  *  File:     SemiSpaceProxy.java

  *----------------------------------------------------------------------------

  *

  * Copyright 2008 Erlend Nossum

  *

  * Licensed under the Apache License, Version 2.0 (the "License"); 

  * you may not use this file except in compliance with the License. 

  * You may obtain a copy of the License at 

  *

  *   http://www.apache.org/licenses/LICENSE-2.0

  *

  * Unless required by applicable law or agreed to in writing, software

  * distributed under the License is distributed on an "AS IS" BASIS,

  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.

  * See the License for the specific language governing permissions and 

  * limitations under the License.

  *

  *  Description:  See javadoc below

  *

  *  Created:      Mar 4, 2008

  * ============================================================================ 

  */

 package org.semispace.ws.client;

 import javax.xml.namespace.QName;

 import javax.xml.ws.Service;

 import javax.xml.ws.soap.SOAPBinding;

 import org.slf4j.Logger;

 import org.slf4j.LoggerFactory;

 import org.semispace.SemiEventListener;

 import org.semispace.SemiEventRegistration;

 import org.semispace.SemiLease;

 import org.semispace.SemiSpaceInterface;

 import org.semispace.ws.WsSpace;

 import org.springframework.context.support.ClassPathXmlApplicationContext;

 import com.thoughtworks.xstream.XStream;

 /**

  * Client side proxy of SemiSpace web services

  */

 public class SemiSpaceProxy implements SemiSpaceInterface {

     private static final Logger log = LoggerFactory.getLogger( SemiSpaceProxy.class );

     private static SemiSpaceProxy instance = null;

     private WsSpace space;

     private XStream xstream;

     private SemiSpaceProxy() {

         xstream = new XStream();

     }

     /**

      * Open WS connection to the defined end point. This should be 

      * something similar to <tt>http://localhost:8080/semispace-war/services/space</tt>.

      */

     public static synchronized SemiSpaceInterface retrieveSpace( String endpoint) {

         if ( instance == null ) {

             instance = retrieveSpace(readSpaceServiceAsStandardPort(endpoint));

             //instance = retrieveSpace(readSpaceServiceAsSpring());

         }

         return instance;

     }

     /**

      * An alternative way of performing lookup

      */

     protected static WsSpace readSpaceServiceAsSpring() {

         ClassPathXmlApplicationContext context = 

             new ClassPathXmlApplicationContext(new String[] {"org/semispace/ws/client/space-bean.xml"});

         WsSpace hw = (WsSpace) context.getBean("space");

         return hw;

     }

     protected static WsSpace readSpaceServiceAsStandardPort() {

         return readSpaceServiceAsStandardPort("http://localhost:8080/semispace-war/services/space");

     }

     protected static WsSpace readSpaceServiceAsStandardPort( String endpointAddress ) {

          QName SERVICE_NAME = new QName("http://ws.semispace.org/", "WsSpace");

          QName PORT_NAME = new QName("http://ws.semispace.org/", "WsSpacePort");

         Service service = Service.create(SERVICE_NAME);

         // Add a port to the Service

         service.addPort(PORT_NAME, SOAPBinding.SOAP11HTTP_BINDING, endpointAddress);

         WsSpace hw = service.getPort(WsSpace.class);

         return hw;

     }

     /**

      * This is a bit roundabout, but is used for junit purposes.

      */

     protected static synchronized SemiSpaceProxy retrieveSpace(WsSpace space ) {

         if ( instance == null ) {

             instance = new SemiSpaceProxy();

             instance.space = space;

         }

         return instance; 

     }

     /**

      * <b>Notify is illegal to use in proxy</b>

      */

     public SemiEventRegistration notify(Object template, SemiEventListener listener, long duration) {

         throw new SemiSpaceProxyException("Illegal to use notify in space proxy.", null);

     }

     public Object read(Object template, long duration) {

         String xml;

         try {

             xml = space.read( toXml( template ), duration);

         } catch (Exception e) {

             throw new SemiSpaceProxyException("Could not read due to connection error.", e);

         }

         return fromXml( xml );

     }

     private Object fromXml(String xml) {

         if ( xml == null ) {

             return null;

         }

         return xstream.fromXML(xml);

     }

     private String toXml(Object template) {

         return xstream.toXML(template);

     }

     public Object readIfExists(Object template) {

         String xml;

         try {

             xml = space.readIfExists( toXml( template ));

         } catch (Exception e) {

             throw new SemiSpaceProxyException("Could not read due to connection error.", e);

         }

         return fromXml( xml );

     }

     public Object take(Object template, long duration) {

         String xml;

         try {

             xml = space.take(toXml( template ), duration);

         } catch (RuntimeException e) {

             throw new SemiSpaceProxyException("Could not take due to connection error.", e);

         }

         return fromXml( xml );

     }

     public Object takeIfExists(Object template) {

         String xml;

         try {

             xml = space.takeIfExists(toXml( template ));

         } catch (RuntimeException e) {

             throw new SemiSpaceProxyException("Could not take due to connection error.", e);

         }

         return fromXml( xml );

     }

     /**

      * TODO Consider fixing that null is always returned.

      * @return will presently ALWAYS return null, even when operation was a success.

      * @see org.semispace.SemiSpaceInterface#write(java.lang.Object, long)

      */

     public SemiLease write(Object obj, long duration) {

         try {

             space.write(toXml(obj), duration);

         } catch (RuntimeException e) {

             throw new SemiSpaceProxyException("Could not write due to connection error.", e);

         }

         return null;

     }

     protected void setSpace(WsSpace space) {

         this.space = space;

     }

 }