Stateful JAX-WS with Coherence*Web (WebLogic Server)

We describe a stateful JAX-WS web service with high availability provided by Coherence*Web [1]. Deployed to two separate WebLogic managed servers, the web service stores its state in http session cookies. Coherence*Web distributes and synchronizes http session data between both managed servers. As a result, two endpoints with synchronized web service state provide high availability. With one endpoint down, another could continue to serve the service request with current web service state.

Note that WebLogic clustering can also provide highly available http sessions. However, we want to demonstrate Coherence*Web as an alternative to clustering for high availability. Therefore, we do not use clustering here. Instead, we use Coherence*Web.

Setting up the stateful web service with Coherence*Web involves the following steps.

start Coherence*Web cache server
create and configure managed servers
- deploy Coherence*Web as a shared library to the managed servers
create and deploy the web service
- stores state in http session
- instrument the web service using Coherence*Web
- deploy the web service to both managed servers

Start Coherence*Web Cache Server

Start Coherence*Web cache server using the command below [2].

java -server -Xms512m -Xmx512m 
-cp coherence/lib/coherence.jar:coherence/lib/coherence-web-spi.war 
-Dtangosol.coherence.management.remote=true 
-Dtangosol.coherence.cacheconfig=WEB-INF/classes/session-cache-config.xml 
-Dtangosol.coherence.session.localstorage=true 
com.tangosol.net.DefaultCacheServer

Create and Configure Managed Servers

Copy coherence/lib/coherence.jar [2] to $DOMAIN_HOME/lib.

Start WebLogic AdminServer using

$DOMAIN_HOME/bin/startWebLogic.sh

Create two managed servers Server-2 at port 7012 and Server-3 at port 7013 using the admin console. Start both servers using the commands below.

$DOMAIN_HOME/bin/startManagedWebLogic.sh Server-2
$DOMAIN_HOME/bin/startManagedWebLogic.sh Server-3

Deploy coherence\lib\coherence-web-api.war [2] to the servers as a shared library.

Create and Deploy the Web Service

Install Oracle Enterprise Pack for Eclipse (OEPE) on Eclipse Galileo [4]. In Eclipse, create a web service using the following WSDL and implementation.

<definitions
 xmlns:soap="http://schemas.xmlsoap.org/wsdl/soap/"
 xmlns:tns="http://oracle.ws.demo/"
 xmlns:xsd="http://www.w3.org/2001/XMLSchema"
 xmlns="http://schemas.xmlsoap.org/wsdl/"
 targetNamespace="http://oracle.ws.demo/"
 name="StatefulWSService">
<types>
<xsd:schema>
<xsd:import namespace="http://oracle.ws.demo/"
 schemaLocation="http://localhost:7001/Stateful_WS_Coherence/StatefulWSService?xsd=1" />
</xsd:schema>
</types>
<message name="addItem">
<part name="parameters" element="tns:addItem" />
</message>
<message name="addItemResponse">
<part name="parameters" element="tns:addItemResponse" />
</message>
<portType name="StatefulWS">
<operation name="addItem">
<input message="tns:addItem" />
<output message="tns:addItemResponse" />
</operation>
</portType>
<binding name="StatefulWSPortBinding" type="tns:StatefulWS">
<soap:binding transport="http://schemas.xmlsoap.org/soap/http" 
style="document" />
<operation name="addItem">
<soap:operation soapAction="" />
<input>
<soap:body use="literal" />
</input>
<output>
<soap:body use="literal" />
</output>
</operation>
</binding>
<service name="StatefulWSService">
<port name="StatefulWSPort" binding="tns:StatefulWSPortBinding">
<soap:address
 location="http://localhost:7001/Stateful_WS_Coherence/StatefulWSService" />
</port>
</service>
</definitions>

StatefulWS.java and Item.java

package demo.ws.oracle;
import javax.jws.WebMethod;
import javax.jws.WebService;
import javax.xml.ws.WebServiceContext;
import javax.xml.ws.*;
import javax.xml.ws.handler.MessageContext;
import javax.jws.*;
import javax.annotation.Resource;
import java.util.*;
import javax.servlet.*;
import javax.servlet.http.*
@WebService
public class StatefulWS {
  @Resource
  WebServiceContext ctx;
  @WebMethod()
  public int addItem(String name) {
    HttpServletRequest req = (HttpServletRequest) 
      ctx.getMessageContext().get(MessageContext.SERVLET_REQUEST);
    HttpSession session = req.getSession(true);
    if (session == null)
      throw new WebServiceException("No HTTP Session found");
    System.out.println("httpsession: id="+session.getId());

    //Get the cart object from the HttpSession
    List<Item> cart = (List<Item>)session.getAttribute("myCart");
    if (cart == null)
    {       cart = new ArrayList();     }
    // Add the item to the cart
    cart.add(new Item(name));
    // Save the updated cart in the HTTPSession
    session.setAttribute("myCart", cart);
    // return the number of items in the stateful cart
    return cart.size();
  }
}
package demo.ws.oracle;
public class Item implements java.io.Serializable {
  public String name;public Item(String name){
      this.name = name;
  }
}

Add coherence-web-api library into weblogic.xml [2].

<weblogic-web-app
 xmlns="http://xmlns.oracle.com/weblogic/weblogic-web-app"
 xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
 xsi:schemaLocation="http://xmlns.oracle.com/weblogic/weblogic-web-app
 http://xmlns.oracle.com/weblogic/weblogic-web-app/1.0/weblogic-web-app.xsd">
  <weblogic-version>10.3.1</weblogic-version>
  <context-root>Stateful_WS_Coherence</context-root>
  <library-ref>
    <library-name>coherence-web-spi</library-name>
    <specification-version>1.0.0.0</specification-version>
    <implementation-version>1.0.0.0</implementation-version>
    <exact-match>false</exact-match>
  </library-ref>
</weblogic-web-app>

Deploy the web service to both managed servers.

Test

Run the test.

package demo.ws;
import demo.ws.oracle.*;
import java.io.IOException;
import java.net.URL;
import java.util.ArrayList;
import java.util.List;
import java.util.Map;
import javax.xml.namespace.QName;
import javax.xml.ws.BindingProvider;

public class StatefulWSClient {
  public static void main(String[] args) throws Exception {
    StatefulWSService service = 
      new StatefulWSService(Thread.currentThread().getContextClassLoader()
        .getResource("META-INF/wsdls/StatefulWSService.wsdl")
        , new QName("http://oracle.ws.demo/", "StatefulWSService"));
    StatefulWS port = service.getStatefulWSPort();

    ((BindingProvider)port).getRequestContext()
      .put(BindingProvider.SESSION_MAINTAIN_PROPERTY, true);

    ((BindingProvider)port).getRequestContext()
      .put(BindingProvider.ENDPOINT_ADDRESS_PROPERTY, 
      "http://stacd15.us.oracle.com:7012/Stateful_WS_Coherence/StatefulWSService");

    System.out.println("calling " + 
      ((BindingProvider)port).getRequestContext()
        .get(BindingProvider.ENDPOINT_ADDRESS_PROPERTY));
    for (int j=0; j<5; j++) {
      try {
        int response = port.addItem("abc");
        System.out.println("Got " + response);
        Thread.currentThread().sleep(3000);
      } catch (Exception ex)  {}
    }

    ((BindingProvider)port).getRequestContext()
      .put(BindingProvider.ENDPOINT_ADDRESS_PROPERTY, 
      "http://stacd15.us.oracle.com:7013/Stateful_WS_Coherence/StatefulWSService");
    System.out.println("calling " + 
      ((BindingProvider)port).getRequestContext()
        .get(BindingProvider.ENDPOINT_ADDRESS_PROPERTY));
    for (int j=0; j<5; j++) {
      try {
        int response = port.addItem("abc");
        System.out.println("Got " + response);
        Thread.currentThread().sleep(3000);
      } catch (Exception ex)  {}
    }
  }
}

The test invokes the web service five times for each endpoint. The output shows that the returned count increases, indicating synchronized web service state across both endpoints.

calling http://stacd15.us.oracle.com:7012/Stateful_WS_Coherence/StatefulWSService
Got 1
Got 2
Got 3
Got 4
Got 5
calling http://stacd15.us.oracle.com:7013/Stateful_WS_Coherence/StatefulWSService
Got 6
Got 7
Got 8
Got 9
Got 10

Both managed servers output the same http session id's.

httpsession: id=tS1DNs2XTJZuQNhNfsl4fvpuj0Qd2ZnmTmHFKtKlUX4EytukR9V0!-280396885!1257829391923
httpsession: id=tS1DNs2XTJZuQNhNfsl4fvpuj0Qd2ZnmTmHFKtKlUX4EytukR9V0!-280396885!1257829391923
httpsession: id=tS1DNs2XTJZuQNhNfs14fvpuj0Qd2ZnmTmHFKtKlUX4EytukR9V0!-280396885!1257829391923
httpsession: id=tS1DNs2XTJZuQNhNfsl4fvpuj0Qd2ZnmTmHFKtKlUX4EytukR9V0!-280396885!1257829391923

WebLogic Server