Chapter 5. Invoking Session Beans

JBoss EAP introduced the EJB client API for managing remote EJB invocations. The JBoss EJB client API uses the EJBClientContext, which may be associated with and be used by one or more threads concurrently. This means an EJBClientContext can potentially contain any number of EJB receivers. An EJB receiver is a component that knows how to communicate with a server that is capable of handling the EJB invocation. Typically, EJB remote applications can be classified into the following:

Depending on the type of remote client, from an EJB client API point of view, there can potentially be more than one EJBClientContext within a JVM.

While standalone applications typically have a single EJBClientContext that may be backed by any number of EJB receivers, this isn’t mandatory. If a standalone application has more than one EJBClientContext, an EJB client context selector is responsible for returning the appropriate context.

In case of remote clients that run within another JBoss EAP instance, each deployed application will have a corresponding EJB client context. Whenever that application invokes another EJB, the corresponding EJB client context is used to find the correct EJB receiver, which then handles the invocation.

Previous versions of JBoss EAP included a feature where the message stream that contained the EJB protocol message could be compressed. This feature has been included in JBoss EAP 6.3 and later.

Data compression hints can be specified via the JBoss annotation org.jboss.ejb.client.annotation.CompressionHint. The hint values specify whether to compress the request, response or request and response. Adding @CompressionHint defaults to compressResponse=true and compressRequest=true.

The annotation can be specified at the interface level to apply to all methods in the EJB’s interface such as:

import org.jboss.ejb.client.annotation.CompressionHint;

@CompressionHint(compressResponse = false)
public interface ClassLevelRequestCompressionRemoteView {
    String echo(String msg);
}

Or the annotation can be applied to specific methods in the EJB’s interface such as:

import org.jboss.ejb.client.annotation.CompressionHint;

public interface CompressableDataRemoteView {

    @CompressionHint(compressResponse = false, compressionLevel = Deflater.BEST_COMPRESSION)
    String echoWithRequestCompress(String msg);

    @CompressionHint(compressRequest = false)
    String echoWithResponseCompress(String msg);

    @CompressionHint
    String echoWithRequestAndResponseCompress(String msg);

    String echoWithNoCompress(String msg);
}

The compressionLevel setting shown above can have the following values:

The compressionLevel setting defaults to Deflater.DEFAULT_COMPRESSION.

Class level annotation with method level overrides:

@CompressionHint
public interface MethodOverrideDataCompressionRemoteView {

    @CompressionHint(compressRequest = false)
    String echoWithResponseCompress(final String msg);

    @CompressionHint(compressResponse = false)
    String echoWithRequestCompress(final String msg);

    String echoWithNoExplicitDataCompressionHintOnMethod(String msg);
}

On the client side ensure the org.jboss.ejb.client.view.annotation.scan.enabled system property is set to true. This property tells JBoss EJB Client to scan for annotations.

The default remote connection port is 8080. The jboss-ejb-client properties file looks like this:

remote.connectionprovider.create.options.org.xnio.Options.SSL_ENABLED=false
remote.connections=default
remote.connection.default.host=localhost
remote.connection.default.port=8080
remote.connection.default.connect.options.org.xnio.Options.SASL_POLICY_NOANONYMOUS=false

Default Connector

The default connector is http-remoting.

Besides EJB client remoting interoperability, you can connect to legacy clients using the following options:

JBoss EAP supports CORBA/IIOP-based access to EJBs deployed on JBoss EAP.

The <iiop> element is used to enable IIOP, CORBA, invocation of EJBs. The presence of this element means that the iiop-openjdk subsystem is installed. The <iiop> element includes the following two attributes:

Enabling IIOP

To enable IIOP you must have the IIOP OpenJDK ORB subsystem installed, and the <iiop/> element present in the ejb3 subsystem configuration. The standalone-full.xml configuration that comes with the distribution has both of these enabled.

IIOP is configured in the iiop-openjdk subsystem of the server configuration file.

<subsystem xmlns="urn:jboss:domain:iiop-openjdk:1.0">

Use the following management CLI command to access and update the iiop-openjdk subsystem.

/subsystem=iiop-openjdk

The IIOP element takes two attributes that control the default behavior of the server.

<subsystem xmlns="urn:jboss:domain:ejb3:1.2">
  ...
  <iiop enable-by-default="false" use-qualified-name="false"/>
  ...
</subsystem>

The following management CLI command adds the <iiop> element under the ejb3 subsystem:

/subsystem=ejb3/service=iiop:add(enable-by-default=false, use-qualified-name=false)

Create an EJB That Communicates Using IIOP

The following example demonstrates how to make a remote IIOP call from the client:

You can determine the EJB client address using the SessionContext interface, as shown in the example below.

public class HelloBean implements HelloBeanRemote {
    @Resource
    SessionContext ctx;
    private Long counter;
    public HelloBean() {
    }
    @PostConstruct
    public void init() {
        counter = 0L;
    }
    @Override
    @RolesAllowed("users")
    public String hello() {
        final String message = "method hello() invoked by user " + ctx.getCallerPrincipal().getName()
                + ", source addr = " +  ctx.getContextData().get("jboss.source-address").toString();
        System.out.println(message);
        return message;
    }
}

Standalone Client Configuration

You can configure the outbound-bind-addresses element within the worker element having namespace urn:xnio:3.5 in the wildfly-client.xml file. The bind-address sub-element takes the attributes match, bind-address, bind-port, as defined below.

The following is an example of the standalone client configuration using the wildfly-client.xml file.

<configuration>
    <worker xmlns="urn:xnio:3.5">
        <worker-name value="default"/>
        <outbound-bind-addresses>
            <bind-address bind-address=IP_ADDRESS_TO_BIND_TO bind-port=OPTIONAL_SOURCE_PORT_NUMBER match=CIDR_BLOCK />
        </outbound-bind-addresses>
    </worker>
</configuration>

The outbound-bind-address requires the following attributes:

Container-based Configuration

Container-based configuration of the EJB client address is similar to the standalone client configuration defined in the wildfly-client.xml file.

The example below configures the outbound-bind-address on the default worker element of the io subsystem, which the ejb3 subsystem uses by default.

/subsystem=io/worker=default/outbound-bind-address=SPECIFY_OUTBOUND_BIND_ADDRESS:add(bind-address=IP_ADDRESS_TO_BIND_TO, bind-port=OPTIONAL_SOURCE_PORT_NUMBER, match=CIDR_BLOCK)

EJB invocation over HTTP includes two distinct parts: the client-side and the server-side implementations.

<dependency>
    <groupId>org.wildfly.wildfly-http-client</groupId>
    <artifactId>wildfly-http-ejb-client</artifactId>
</dependency>

/subsystem=undertow/server=default-server/host=default-host/setting=http-invoker:add(http-authentication-factory=myfactory, path='wildfly-services')