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@WebService handlers with @HandlerChain

In this example we see a basic JAX-WS @WebService component use a handler chain to alter incoming and outgoing SOAP messages. SOAP Handlers are similar to Servlet Filters or EJB/CDI Interceptors.

At high level, the steps involved are:

  1. Create handler(s) implementing jakarta.xml.ws.handler.soap.SOAPHandler

  2. Declare and order them in an xml file via <handler-chain>

  3. Associate the xml file with an @WebService component via @HandlerChain

The @HandlerChain

First we’ll start with our plain @WebService bean, called Calculator, which is annotated with @HandlerChain

@Singleton
@WebService(
        portName = "CalculatorPort",
        serviceName = "CalculatorService",
        targetNamespace = "http://superbiz.org/wsdl",
        endpointInterface = "org.superbiz.calculator.wsh.CalculatorWs")
@HandlerChain(file = "handlers.xml")
public class Calculator implements CalculatorWs {

    public int sum(int add1, int add2) {
        return add1 + add2;
    }

    public int multiply(int mul1, int mul2) {
        return mul1 * mul2;
    }
}

Here we see @HandlerChain pointing to a file called handlers.xml. This file could be called anything, but it must be in the same jar and java package as our Calculator component.

The <handler-chains> file

Our Calculator service is in the package org.superbiz.calculator.wsh, which means our handler chain xml file must be at org/superbiz/calculator/wsh/handlers.xml in our application’s classpath or the file will not be found and no handlers will be used.

In maven we achieve this by putting our handlers.xml in src/main/resources like so:

  • src/main/resources/org/superbiz/calculator/wsh/handlers.xml

With this file we declare and order our handler chain.

<?xml version="1.0" encoding="UTF-8"?>
<handler-chains xmlns="http://java.sun.com/xml/ns/javaee">
  <handler-chain>
    <handler>
      <handler-name>org.superbiz.calculator.wsh.Inflate</handler-name>
      <handler-class>org.superbiz.calculator.wsh.Inflate</handler-class>
    </handler>
    <handler>
      <handler-name>org.superbiz.calculator.wsh.Increment</handler-name>
      <handler-class>org.superbiz.calculator.wsh.Increment</handler-class>
    </handler>
  </handler-chain>
</handler-chains>

The order as you might suspect is:

  • Inflate

  • Increment

The SOAPHandler implementation

Our Inflate handler has the job of monitoring responses to the sum and multiply operations and making them 1000 times better. Manipulation of the message is done by walking the SOAPBody and editing the nodes. The handleMessage method is invoked for both requests and responses, so it is important to check the SOAPBody before attempting to naviage the nodes.

import org.w3c.dom.Node;
import javax.xml.namespace.QName;
import jakarta.xml.soap.SOAPBody;
import jakarta.xml.soap.SOAPException;
import jakarta.xml.soap.SOAPMessage;
import jakarta.xml.ws.handler.MessageContext;
import jakarta.xml.ws.handler.soap.SOAPHandler;
import jakarta.xml.ws.handler.soap.SOAPMessageContext;
import java.util.Collections;
import java.util.Set;

public class Inflate implements SOAPHandler<SOAPMessageContext> {

    public boolean handleMessage(SOAPMessageContext mc) {
        try {
            final SOAPMessage message = mc.getMessage();
            final SOAPBody body = message.getSOAPBody();
            final String localName = body.getFirstChild().getLocalName();

            if ("sumResponse".equals(localName) || "multiplyResponse".equals(localName)) {
                final Node responseNode = body.getFirstChild();
                final Node returnNode = responseNode.getFirstChild();
                final Node intNode = returnNode.getFirstChild();

                final int value = new Integer(intNode.getNodeValue());
                intNode.setNodeValue(Integer.toString(value * 1000));
            }

            return true;
        } catch (SOAPException e) {
            return false;
        }
    }

    public Set<QName> getHeaders() {
        return Collections.emptySet();
    }

    public void close(MessageContext mc) {
    }

    public boolean handleFault(SOAPMessageContext mc) {
        return true;
    }
}

The Increment handler is identical in code and therefore not shown. Instead of multiplying by 1000, it simply adds 1.

The TestCase

We use the JAX-WS API to create a Java client for our Calculator web service and use it to invoke both the sum and multiply operations. Note the clever use of math to assert both the existence and order of our handlers. If Inflate and Increment were reversed, the responses would be 11000 and 13000 respectively.

public class CalculatorTest {

    @BeforeClass
    public static void setUp() throws Exception {
        Properties properties = new Properties();
        properties.setProperty("openejb.embedded.remotable", "true");
        EJBContainer.createEJBContainer(properties);
    }

    @Test
    public void testCalculatorViaWsInterface() throws Exception {
        final Service calculatorService = Service.create(
                new URL("http://127.0.0.1:4204/Calculator?wsdl"),
                new QName("http://superbiz.org/wsdl", "CalculatorService"));

        assertNotNull(calculatorService);

        final CalculatorWs calculator = calculatorService.getPort(CalculatorWs.class);

        // we expect our answers to come back 1000 times better, plus one!
        assertEquals(10001, calculator.sum(4, 6));
        assertEquals(12001, calculator.multiply(3, 4));
    }
}

Running the example

Simply run mvn clean install and you should see output similar to the following:

-------------------------------------------------------
 T E S T S
-------------------------------------------------------
Running org.superbiz.calculator.wsh.CalculatorTest
INFO - openejb.home = /Users/dblevins/work/all/trunk/openejb/examples/webservice-handlers
INFO - openejb.base = /Users/dblevins/work/all/trunk/openejb/examples/webservice-handlers
INFO - Using 'jakarta.ejb.embeddable.EJBContainer=true'
INFO - Cannot find the configuration file [conf/openejb.xml].  Will attempt to create one for the beans deployed.
INFO - Configuring Service(id=Default Security Service, type=SecurityService, provider-id=Default Security Service)
INFO - Configuring Service(id=Default Transaction Manager, type=TransactionManager, provider-id=Default Transaction Manager)
INFO - Creating TransactionManager(id=Default Transaction Manager)
INFO - Creating SecurityService(id=Default Security Service)
INFO - Beginning load: /Users/dblevins/work/all/trunk/openejb/examples/webservice-handlers/target/test-classes
INFO - Beginning load: /Users/dblevins/work/all/trunk/openejb/examples/webservice-handlers/target/classes
INFO - Configuring enterprise application: /Users/dblevins/work/all/trunk/openejb/examples/webservice-handlers
INFO - Auto-deploying ejb Calculator: EjbDeployment(deployment-id=Calculator)
INFO - Configuring Service(id=Default Singleton Container, type=Container, provider-id=Default Singleton Container)
INFO - Auto-creating a container for bean Calculator: Container(type=SINGLETON, id=Default Singleton Container)
INFO - Creating Container(id=Default Singleton Container)
INFO - Configuring Service(id=Default Managed Container, type=Container, provider-id=Default Managed Container)
INFO - Auto-creating a container for bean org.superbiz.calculator.wsh.CalculatorTest: Container(type=MANAGED, id=Default Managed Container)
INFO - Creating Container(id=Default Managed Container)
INFO - Enterprise application "/Users/dblevins/work/all/trunk/openejb/examples/webservice-handlers" loaded.
INFO - Assembling app: /Users/dblevins/work/all/trunk/openejb/examples/webservice-handlers
INFO - Created Ejb(deployment-id=Calculator, ejb-name=Calculator, container=Default Singleton Container)
INFO - Started Ejb(deployment-id=Calculator, ejb-name=Calculator, container=Default Singleton Container)
INFO - Deployed Application(path=/Users/dblevins/work/all/trunk/openejb/examples/webservice-handlers)
INFO - Initializing network services
INFO - Creating ServerService(id=httpejbd)
INFO - Creating ServerService(id=cxf)
INFO - Creating ServerService(id=admin)
INFO - Creating ServerService(id=ejbd)
INFO - Creating ServerService(id=ejbds)
INFO - Initializing network services
INFO -   ** Starting Services **
INFO -   NAME                 IP              PORT
INFO -   httpejbd             127.0.0.1       4204
INFO - Creating Service {http://superbiz.org/wsdl}CalculatorService from class org.superbiz.calculator.wsh.CalculatorWs
INFO - Setting the server's publish address to be http://nopath:80
INFO - Webservice(wsdl=http://127.0.0.1:4204/Calculator, qname={http://superbiz.org/wsdl}CalculatorService) --> Ejb(id=Calculator)
INFO -   admin thread         127.0.0.1       4200
INFO -   ejbd                 127.0.0.1       4201
INFO -   ejbd                 127.0.0.1       4203
INFO - -------
INFO - Ready!
INFO - Creating Service {http://superbiz.org/wsdl}CalculatorService from WSDL: http://127.0.0.1:4204/Calculator?wsdl
INFO - Creating Service {http://superbiz.org/wsdl}CalculatorService from WSDL: http://127.0.0.1:4204/Calculator?wsdl
INFO - Default SAAJ universe not set
Tests run: 1, Failures: 0, Errors: 0, Skipped: 0, Time elapsed: 2.783 sec

Results :

Tests run: 1, Failures: 0, Errors: 0, Skipped: 0

Inspecting the messages

The execution above would generate the following messages.

Calculator wsdl

<?xml version="1.0" encoding="UTF-8"?>
<wsdl:definitions xmlns:wsdl="http://schemas.xmlsoap.org/wsdl/"
                  name="CalculatorService" targetNamespace="http://superbiz.org/wsdl"
                  xmlns:soap="http://schemas.xmlsoap.org/wsdl/soap/"
                  xmlns:tns="http://superbiz.org/wsdl" xmlns:xsd="http://www.w3.org/2001/XMLSchema">
  <wsdl:types>
    <xsd:schema attributeFormDefault="unqualified" elementFormDefault="unqualified"
                targetNamespace="http://superbiz.org/wsdl" xmlns:tns="http://superbiz.org/wsdl"
                xmlns:xsd="http://www.w3.org/2001/XMLSchema">
      <xsd:element name="multiply" type="tns:multiply"/>
      <xsd:complexType name="multiply">
        <xsd:sequence>
          <xsd:element name="arg0" type="xsd:int"/>
          <xsd:element name="arg1" type="xsd:int"/>
        </xsd:sequence>
      </xsd:complexType>
      <xsd:element name="multiplyResponse" type="tns:multiplyResponse"/>
      <xsd:complexType name="multiplyResponse">
        <xsd:sequence>
          <xsd:element name="return" type="xsd:int"/>
        </xsd:sequence>
      </xsd:complexType>
      <xsd:element name="sum" type="tns:sum"/>
      <xsd:complexType name="sum">
        <xsd:sequence>
          <xsd:element name="arg0" type="xsd:int"/>
          <xsd:element name="arg1" type="xsd:int"/>
        </xsd:sequence>
      </xsd:complexType>
      <xsd:element name="sumResponse" type="tns:sumResponse"/>
      <xsd:complexType name="sumResponse">
        <xsd:sequence>
          <xsd:element name="return" type="xsd:int"/>
        </xsd:sequence>
      </xsd:complexType>
    </xsd:schema>
  </wsdl:types>
  <wsdl:message name="multiplyResponse">
    <wsdl:part element="tns:multiplyResponse" name="parameters">
    </wsdl:part>
  </wsdl:message>
  <wsdl:message name="sumResponse">
    <wsdl:part element="tns:sumResponse" name="parameters">
    </wsdl:part>
  </wsdl:message>
  <wsdl:message name="sum">
    <wsdl:part element="tns:sum" name="parameters">
    </wsdl:part>
  </wsdl:message>
  <wsdl:message name="multiply">
    <wsdl:part element="tns:multiply" name="parameters">
    </wsdl:part>
  </wsdl:message>
  <wsdl:portType name="CalculatorWs">
    <wsdl:operation name="multiply">
      <wsdl:input message="tns:multiply" name="multiply">
      </wsdl:input>
      <wsdl:output message="tns:multiplyResponse" name="multiplyResponse">
      </wsdl:output>
    </wsdl:operation>
    <wsdl:operation name="sum">
      <wsdl:input message="tns:sum" name="sum">
      </wsdl:input>
      <wsdl:output message="tns:sumResponse" name="sumResponse">
      </wsdl:output>
    </wsdl:operation>
  </wsdl:portType>
  <wsdl:binding name="CalculatorServiceSoapBinding" type="tns:CalculatorWs">
    <soap:binding style="document" transport="http://schemas.xmlsoap.org/soap/http"/>
    <wsdl:operation name="multiply">
      <soap:operation soapAction="" style="document"/>
      <wsdl:input name="multiply">
        <soap:body use="literal"/>
      </wsdl:input>
      <wsdl:output name="multiplyResponse">
        <soap:body use="literal"/>
      </wsdl:output>
    </wsdl:operation>
    <wsdl:operation name="sum">
      <soap:operation soapAction="" style="document"/>
      <wsdl:input name="sum">
        <soap:body use="literal"/>
      </wsdl:input>
      <wsdl:output name="sumResponse">
        <soap:body use="literal"/>
      </wsdl:output>
    </wsdl:operation>
  </wsdl:binding>
  <wsdl:service name="CalculatorService">
    <wsdl:port binding="tns:CalculatorServiceSoapBinding" name="CalculatorPort">
      <soap:address location="http://127.0.0.1:4204/Calculator?wsdl"/>
    </wsdl:port>
  </wsdl:service>
</wsdl:definitions>

SOAP sum and sumResponse

Request:

<?xml version="1.0" encoding="UTF-8"?>
<soap:Envelope xmlns:soap="http://schemas.xmlsoap.org/soap/envelope/">
  <soap:Body>
    <ns1:sum xmlns:ns1="http://superbiz.org/wsdl">
      <arg0>4</arg0>
      <arg1>6</arg1>
    </ns1:sum>
  </soap:Body>
</soap:Envelope>

Response:

<?xml version="1.0" encoding="UTF-8"?>
<soap:Envelope xmlns:soap="http://schemas.xmlsoap.org/soap/envelope/">
  <soap:Body>
    <ns1:sumResponse xmlns:ns1="http://superbiz.org/wsdl">
      <return>10001</return>
    </ns1:sumResponse>
  </soap:Body>
</soap:Envelope>

SOAP multiply and multiplyResponse

Request:

<?xml version="1.0" encoding="UTF-8"?>
<soap:Envelope xmlns:soap="http://schemas.xmlsoap.org/soap/envelope/">
  <soap:Body>
    <ns1:multiply xmlns:ns1="http://superbiz.org/wsdl">
      <arg0>3</arg0>
      <arg1>4</arg1>
    </ns1:multiply>
  </soap:Body>
</soap:Envelope>

Response:

<?xml version="1.0" encoding="UTF-8"?>
<soap:Envelope xmlns:soap="http://schemas.xmlsoap.org/soap/envelope/">
  <soap:Body>
    <ns1:multiplyResponse xmlns:ns1="http://superbiz.org/wsdl">
      <return>12001</return>
    </ns1:multiplyResponse>
  </soap:Body>
</soap:Envelope>

APIs Used