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<h1>Axis2 Integration with the Spring Framework</h1>

<p>This document is a guide on how to use Axis2 with the Spring Framework</p>

<h2>Content</h2>
<ul>
  <li><a href="#1">Introduction</a></li>
  <li><a href="#2">Configuring Axis2 to be Spring Aware</a>
    <ul>
      <li><a href="#21">Programming Model</a></li>
      <li><a href="#22">Simple Spring Config Example</a></li>
      <li><a href="#23">With a ServletContext</a></li>
      <li><a href="#24">Without a ServletContext</a></li>
      <li><a href="#25">Putting it All Together</a></li>
      <li><a href="#26">Spring Inside an AAR </a>
        <ul>
          <li><a href="#261">The Spring Inside an AAR Layout</a></li>
          <li><a href="#262">The Spring Inside an AAR init Class</a></li>
          <li><a href="#263">Known Issues Running Spring Inside the
          AAR</a></li>
        </ul>
      </li>
    </ul>
  </li>
</ul>
<a name="1"></a>

<h2>Introduction</h2>

<p>Axis2 and Spring integration takes place when Spring supplies one of its
pre-loaded beans to the Axis2 Message Receiver defined in the AAR
services.xml. Axis2 typically uses reflection to instantiate the ServiceClass
defined in the services.xml used by the Message Receiver. Alternatively, you
can define a ServiceObjectSupplier that will supply the Object.</p>

<p>This guide describes how to use two separate ServiceObjectSupplier classes
that are a part of the Axis2 standard distribution - one for use with a
ServletContext, and one without. Configuring Axis2 with a ServletContext is 
simpler than without, and is recommended for most use cases. Without a 
ServletContext, ie, Spring inside the AAR, requires an extra Spring bean 
and is considered an advanced use case. Once configured, the Web service itself 
acts like any other Spring wired bean. These Spring beans can be loaded any way
desired as Axis2 has no configuration file dependencies from Spring. Spring
versions 1.2.6, 1.2.8 and 2.0 have been tested, but probably any version
would work as only the core functionality is required.</p>

<p>This guide assumes some basic knowledge of Axis2. See the <a
href="userguide.html">User's Guide</a> for more information.</p>
<a name="2"></a>

<h3>Programming Model</h3>

<p>From an Axis2 standpoint, two hooks are needed to be placed into the AAR
services.xml - the ServiceObjectSupplier that hooks Axis2 and Spring
together, and the name of the Spring bean that Axis2 will use as the service.
All Message Receivers are currently supported, as would be any Message
Receiver that extends org.apache.axis2.receivers.AbstractMessageReceiver .</p>
<a name="22"></a>

<h3>Simple Spring Config Example</h3>

<p>For the purpose of this example, we'll configure Spring via a WAR file's
web.xml. Let's add a context-param and a listener:</p>
<pre>&lt;listener&gt;
        &lt;listener-class&gt;org.springframework.web.context.ContextLoaderListener&lt;/listener-class&gt;
&lt;/listener&gt;
&lt;context-param&gt;
      &lt;param-name&gt;contextConfigLocation&lt;/param-name&gt;
      &lt;param-value&gt;/WEB-INF/applicationContext.xml&lt;/param-value&gt;
&lt;/context-param&gt;</pre>

<p>Next we will show two examples of Spring's /WEB-INF/applicationContext.xml
referenced in the web.xml listener -  one using a ServletContext, and one
without.</p>
<a name="23"></a>

<h3>With a ServletContext</h3>

<p>This example (with a ServletContext) applicationContext.xml should be
familiar to any Spring user:</p>
<pre>&lt;?xml version="1.0" encoding="UTF-8"?&gt;
&lt;!DOCTYPE beans PUBLIC "-//SPRING//DTD BEAN//EN" "http://www.springframework.org/dtd/spring-beans.dtd"&gt;

&lt;beans&gt;
  &lt;!-- Axis2 Web Service, but to Spring, its just another bean that has dependencies --&gt;
  &lt;bean id="springAwareService" class="spring.SpringAwareService"&gt;
    &lt;property name="myBean" ref="myBean"/&gt;
  &lt;/bean&gt;

  &lt;!-- just another bean / interface with a wired implementation, that's injected by Spring
          into the Web Service --&gt;
   &lt;bean id="myBean" class="spring.MyBeanImpl"&gt;
     &lt;property name="val" value="Spring, emerge thyself" /&gt;
  &lt;/bean&gt;
&lt;/beans&gt;</pre>

<p>If the service is running in a Servlet Container, i.e., Axis2 will be able
to get a hold of the ServletContext, the services.xml for the example would
be using SpringServletContextObjectSupplier such as:</p>
<pre> &lt;service name="SpringAwareService"&gt;
    &lt;description&gt;
        simple spring example
    &lt;/description&gt;
    &lt;parameter name="ServiceObjectSupplier"&gt;org.apache.axis2.extensions.spring.receivers.SpringServletContextObjectSupplier&lt;/parameter&gt;
    &lt;parameter name="SpringBeanName"&gt;springAwareService&lt;/parameter&gt;
    &lt;operation name="getValue"&gt;
        &lt;messageReceiver class="org.apache.axis2.receivers.RawXMLINOutMessageReceiver"/&gt;
    &lt;/operation&gt;
&lt;/service&gt; </pre>

<p>While the above example uses RawXMLINOutMessageReceiver as its
messageReceiver class, all Message Receivers are currently supported, as
would be any Message Receiver that extends
org.apache.axis2.receivers.AbstractMessageReceiver .</p>
<a name="24"></a>

<h3>Without a ServletContext</h3>

<p>In case Axis2 can't get a ServletContext, (i.e., uses a different
transport or is running Axis2 inside the AAR etc,) you have the option of
defining a bean that takes advantage of Spring's internal abilities
(ApplicationContextAware interface, specifically) to provide an Application
Context to Axis2, with a bean ref 'applicationContext' :</p>
<pre>&lt;?xml version="1.0" encoding="UTF-8"?&gt;
&lt;!DOCTYPE beans PUBLIC "-//SPRING//DTD BEAN//EN" "http://www.springframework.org/dtd/spring-beans.dtd"&gt;

&lt;beans&gt;
  &lt;!-- Configure spring to give a hook to axis2 without a ServletContext --&gt;
  &lt;bean id="applicationContext" 
    class="org.apache.axis2.extensions.spring.receivers.ApplicationContextHolder" /&gt;

  &lt;!-- Axis2 Web Service, but to Spring, its just another bean that has dependencies --&gt;
  &lt;bean id="springAwareService"
        class="spring.SpringAwareService"&gt;
    &lt;property name="myBean" ref="myBean" /&gt;
  &lt;/bean&gt;

  &lt;!-- just another bean with a wired implementation, that's injected by Spring 
          into the Web Service --&gt;
   &lt;bean id="myBean"
        class="spring.MyBeanImpl"&gt;
     &lt;property name="val" value="Spring, emerge thyself" /&gt;
  &lt;/bean&gt;
&lt;/beans&gt;</pre>

<p>If the service is <strong>not</strong> running in a Servlet Container,
i.e., Axis2 will not be able to get a hold of ServletContext or you prefer
not to, the services.xml for the example will be using
SpringAppContextAwareObjectSupplier such as:</p>
<pre> &lt;service name="SpringAwareService"&gt;
    &lt;description&gt;
        simple spring example
    &lt;/description&gt;
    &lt;parameter name="ServiceObjectSupplier"&gt;org.apache.axis2.extensions.spring.receivers.SpringAppContextAwareObjectSupplier&lt;/parameter&gt;
    &lt;parameter name="SpringBeanName"&gt;springAwareService&lt;/parameter&gt;
    &lt;operation name="getValue"&gt;
        &lt;messageReceiver class="org.apache.axis2.receivers.RawXMLINOutMessageReceiver"/&gt;
    &lt;/operation&gt;
&lt;/service&gt; </pre>

<p>While the above example uses RawXMLINOutMessageReceiver as its
messageReceiver class, all Message Receivers are currently supported, as
would be any Message Receiver that extends
org.apache.axis2.receivers.AbstractMessageReceiver .</p>

<p>In an environment <strong>without a ServletContext</strong>, one way you
could load the applicationContext.xml file is in a place that will be run
once. Upon start-up, execute the following:</p>
<pre>import org.springframework.context.support.ClassPathXmlApplicationContext;

 public void createSpringAppCtx(ClassLoader cl)
            throws Exception {

    ClassPathXmlApplicationContext ctx = new
      ClassPathXmlApplicationContext(new String[] {Constants.MY_PATH +
      "spring/applicationContext.xml"}, false);
           ctx.setClassLoader(cl);
           ctx.refresh();</pre>
} <a name="25"></a>

<h3>Putting It All Together</h3>

<p>From here, it's just standard Axis2 coding. Only now the service has
Spring wiring capabilities. The implementation is the same whether using
either SpringServletContextObjectSupplier or
SpringAppContextAwareObjectSupplier. The service is as follows:</p>
<pre>package spring;

import org.apache.axiom.om.OMAbstractFactory;
import org.apache.axiom.om.OMElement;
import org.apache.axiom.om.OMFactory;
import org.apache.axiom.om.OMNamespace;
import org.apache.axiom.om.OMText;

public class SpringAwareService {

    private MyBean myBean = null;

    //spring 'injects' this implementation
    public void setMyBean(MyBean myBean) {
            this.myBean = myBean;
    }

    // The web service
    public OMElement getValue(OMElement ignore) {
            OMFactory factory=
                OMAbstractFactory.getOMFactory();
            OMNamespace payloadNs= factory.createOMNamespace(
                "http://springExample.org/example1", "example1");
            OMElement payload =
                factory.createOMElement("string", payloadNs);
            OMText response = factory.createOMText(this.myBean.emerge());
            payload.addChild(response);
            return payload;
    }
} </pre>

<p>For those who are new to Spring, one of the ideas is that you program an
Interface, as the implementation is pluggable. This idea is referenced in the
Spring config file above. Below is the interface:</p>
<pre>package spring;

/** Interface for Spring aware Bean */
public interface MyBean {
         String emerge();
}</pre>

<p>Here's the implementation:</p>
<pre>/** Spring wired implementation */
public class MyBeanImpl implements MyBean {

    String str = null;
    // spring 'injects' this value
    public void setVal(String s) {
        str = s;
    }
    // web service gets this value
    public String emerge() {
        return str;
    }
}</pre>

<p>Lastly here's the client - not really necessary for the example, other
than for completeness:</p>
<pre>package client;

import java.io.StringWriter;

import javax.xml.stream.XMLOutputFactory;

import org.apache.axiom.om.OMAbstractFactory;
import org.apache.axiom.om.OMElement;
import org.apache.axiom.om.OMFactory;
import org.apache.axiom.om.OMNamespace;
import org.apache.axis2.addressing.EndpointReference;
import org.apache.axis2.client.Options;
import org.apache.axis2.client.ServiceClient;

public class TestClient {
    private static EndpointReference targetEPR =
        new EndpointReference(
               "http://localhost:8080/axis2/services/SpringAwareService");

    /**
     * Simple axis2 client.
     *
     * @param args Main
     */
    public static void main(String[] args) {
        try {
            OMFactory factory = OMAbstractFactory.getOMFactory();
            OMNamespace omNs = factory.createOMNamespace(
                        "http://springExample.org/example1", "example1");

            OMElement method = factory.createOMElement("getValue", omNs);
            OMElement value = factory.createOMElement("Text", omNs);
            value.addChild(factory.createOMText(value, "Some String "));
            method.addChild(value);

            ServiceClient serviceClient = new ServiceClient();

            Options options = new Options();
            serviceClient.setOptions(options);
            options.setTo(targetEPR);

            //Blocking invocation
            OMElement result = serviceClient.sendReceive(method);

            StringWriter writer = new StringWriter();
            result.serialize(XMLOutputFactory.newInstance()
                    .createXMLStreamWriter(writer));
            writer.flush();

            System.out.println("Response: " + writer.toString());
        } catch (Exception ex) {
            ex.printStackTrace();
        }
    }
} </pre>

<p>The examples above assume that both the spring framework .jar and the
axis2-spring-*.jar are under WEB-INF/lib. In such a case, the classes shown
in this tutorial need to be placed in a JAR under WEB-INF/lib. In this
example the JAR layout is:</p>
<source><pre>./mySpring.jar
./META-INF
./META-INF/MANIFEST.MF
./spring
./spring/MyBean.class
./spring/MyBeanImpl.class
./spring/SpringAwareService.class</pre>
</source>
<p>Since all the user classes are in mySpring.jar in this example, the AAR
merely contains the services.xml file:</p>
<source><pre>./springExample.aar
./META-INF
./META-INF/MANIFEST.MF
./META-INF/services.xml</pre>
</source>
<p>To run this example, make sure you have the axis2-spring*.jar that comes
from the axis2-std-*-bin distro in the server side WEB-INF/lib, as well as
the appropriate Spring jar - most will use the full spring.jar, but the
minimum requirements are spring-core, spring-beans, spring-context, and
spring-web. When running the client, you should see this output:</p>
<pre>Response: &lt;example1:string xmlns:example1="http://springExample.org/example1" 
  xmlns:tns="http://ws.apache.org/axis2"&gt;Spring, emerge thyself&lt;/example1:string&gt;</pre>
<a name="26"></a>

<h3>Spring Inside an AAR</h3>

<p>Axis2 users frequently want to run Spring inside the AAR. Here we show you
how it is done. There are four points to be aware of:</p>

<p>(A) You need to configure Spring to use the Axis2 Service Classloader. See
the <a href="#263">Known issues running Spring inside the AAR</a> area.</p>

<p>(B) It's up to you to load Spring, though we give an example below.</p>

<p>(C) For reasons such as classloader isolation, the
SpringAppContextAwareObjectSupplier is the best choice.</p>

<p>(D) The springframework .jar and axis2-spring-*.jar will be placed inside
the AAR under the lib directory. Please <strong>move</strong> the
axis2-spring-*.jar from WEB-INF/lib to inside the AAR, as shown below - it
will <strong>not</strong> work otherwise.</p>
<ul>
  <li><strong><a name="261"></a>The Spring inside an AAR layout</strong></li>
</ul>
<source><pre>./springExample.aar
./META-INF
./META-INF/MANIFEST.MF
./META-INF/services.xml
./applicationContext.xml
./lib
./lib/axis2-spring-1.4.jar
./lib/spring.jar
./spring
./spring/MyBean.class
./spring/MyBeanImpl.class
./spring/SpringAwareService.class
./spring/SpringInit.class </pre>
</source>
<p>As explained in the <a href="#24">Without a ServletContext</a> section,
the 'Spring inside an AAR' config needs to hook Axis2 and Spring together via
a Spring bean. Place the following in your Spring config file:</p>
<pre>  &lt;!-- Configure spring to give a hook to axis2 without a ServletContext --&gt;
  &lt;bean id="applicationContext" 
    class="org.apache.axis2.extensions.spring.receivers.ApplicationContextHolder" /&gt;</pre>
<ul>
  <li><strong><a name="262"></a>The Spring inside an AAR init
  class</strong></li>
</ul>

<p>One way to initialize Spring inside the AAR is to use the
org.apache.axis2.engine.ServiceLifeCycle interface. Here we give an
example:</p>
<source><pre>package spring;

import org.apache.axis2.engine.ServiceLifeCycle;
import org.apache.axis2.context.ConfigurationContext;
import org.apache.axis2.description.AxisService;
import org.springframework.context.support.ClassPathXmlApplicationContext;

public class SpringInit implements ServiceLifeCycle {
        
    /**
     * This will be called during the deployement time of the service. 
     * irrespective
     * of the service scope this method will be called
     */
    public void startUp(ConfigurationContext ignore, AxisService service) {
 
        try {
            System.out.println("Starting spring init");
            ClassLoader classLoader = service.getClassLoader();
            ClassPathXmlApplicationContext appCtx = new
            ClassPathXmlApplicationContext(new String[] {"applicationContext.xml"}, false);
                appCtx.setClassLoader(classLoader);
                appCtx.refresh();
            System.out.println("spring loaded");
        } catch (Exception ex) {
            ex.printStackTrace();
        }
    }

    /**
     * This will be called during the system shut down time. 
     * irrespective
     * of the service scope this method will be called
     */
    public void shutDown(ConfigurationContext ctxIgnore, AxisService ignore) {
    }
}</pre>
</source>
<p>Here's the services.xml that now includes SpringInit and the
SpringAwareService shown above. There is also the composite parameter which
is needed when loading Spring in the AAR - see the <a href="#263">Known
issues running Spring inside the AAR</a> area.</p>
<source><pre>&lt;serviceGroup&gt;
  &lt;!-- Invoke SpringInit on server startup and shutdown --&gt;
  &lt;service name="SpringAwareService" class="spring.SpringInit"&gt;
    &lt;description&gt;
         simple spring example - inside the AAR
    &lt;/description&gt;
    &lt;!-- need the TCCL param when using spring inside the AAR --&gt;
    &lt;parameter name="ServiceTCCL"&gt;composite&lt;/parameter&gt;
    &lt;parameter name="ServiceObjectSupplier"&gt;org.apache.axis2.extensions.spring.receivers.SpringAppContextAwareObjectSupplier&lt;/parameter&gt;
    &lt;parameter name="SpringBeanName"&gt;springAwareService&lt;/parameter&gt;
    &lt;operation name="getValue"&gt;
        &lt;messageReceiver class="org.apache.axis2.receivers.RawXMLINOutMessageReceiver"/&gt;
    &lt;/operation&gt;
  &lt;/service&gt;
&lt;/serviceGroup&gt;</pre>
</source><ul>
  <li><strong><a name="263"></a>Known issues running Spring inside the
    AAR</strong></li>
</ul>

<p>By default, the Axis2 classloader strategy does not permit Spring to run
inside the AAR. To allow Spring to run inside the AAR, the 'composite'
parameter is used in the services.xml as shown in the example above. There
was default behavior of 'composite' in the development cycle in between 1.0
and 1.1, but it resulted in the JIRA issue AXIS2-1214 -problems with getting
an initContext.lookup() handle inside the AAR. Spring users typically have
little desire to use initContext.lookup(), as they get their Datasources via
org.springframework.jdbc.datasource.DriverManagerDataSource in an XML file or
with annotations. For EJB home references and the like, Spring provides
JndiObjectFactoryBean. </p>

<p>A common requirement is to run Hibernate along with Spring with Axis2 web services.
It is easier to run Hibernate as well as Spring outside the AAR as shown in the 
ServletContext example, ie, place the Spring and Hibernate jars in WEB-INF/lib and 
the hibernate config files under WEB-INF/classes. With that advisement, Spring provides
an API that allows Spring to load Hibernate under the contraints of an AAR. </p>

<p>Hibernate by default looks for its config files in the classpath. By running Hibernate
inside the AAR, Hibernate won't be able to find its config files. The way to get 
around this limitation is either to expand the AAR or place the hibernate config
files in a specific directory under WEB-INF/classes - and then use 
<a href="http://www.springframework.org/docs/api/org/springframework/orm/hibernate/LocalSessionFactoryBean.html#setMappingDirectoryLocations(org.springframework.core.io.Resource[])">Spring's setMappingDirectoryLocations</a> for several options.  </p>

<p>By placing Spring into DEBUG mode you can look at the logs to see where Spring will look
for your jar / class locations. Use the wildcards in the following example to list your mapping 
locations as shown:  </p>

<source><pre>&lt;bean id="mySessionFactory" class="org.springframework.orm.hibernate3.LocalSessionFactoryBean"&gt;
                &lt;property name="mappingLocations"&gt;
                   &lt;value&gt;classpath*:**/MyEntity.hbm.xml&lt;/value&gt;
                &lt;/property&gt;
                ...
&lt;/bean&gt; </pre>
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