ProcessorService is injected directly into the processorService field on the bean class. in Java

Drawer QR Code ISO/IEC18004 in Java ProcessorService is injected directly into the processorService field on the bean class.

From this field, we can obtain the proxy object that implements the service endpoint interface. You will see in the next section how to configure an XML deployment descriptor to populate the field. Invoking this proxy within a transactional business process such as bookPassage() presents a few problems of which you should be aware. If the proxy encounters a networking problem or SOAP processing error, it throws a RemoteException, which is caught and rethrown as an EJBException, causing the entire transaction to roll back. However, if an error occurs after the web service has executed but before the EJB method successfully returns, a partial rollback occurs; the reservation is rolled back, but the charge made using the Charge-It web service is not. Invocations on web services do not participate in the caller s transaction context!

We still need to specify where and how this web service reference is defined. To do this we need a <service-ref> element in our EJB deployment descriptor. This XML element binds a JAX-RPC service to the JNDI ENC and injects it into the processorService field of our bean class. EJB XML is allowed to be a partial deployment descriptor. This means that we do not have to define every single piece of metadata in XML just because we want to inject a web service into our bean class. The partial XML deployment descriptor of the TravelAgent EJB declares a <service-ref> element that looks like this:

< xml version='1.0' encoding='UTF-8' > <ejb-jar xmlns="http://java.sun.com/xml/ns/j2ee" xmlns:xsi=http://www.w3.org/2001/XMLSchema-instance xmlns:chargeIt="http://charge-it.com/Processor" xsi:schemaLocation="http://java.sun.com/xml/ns/j2ee http://java.sun.com/xml/ns/j2ee/ejb-jar_3_1.xsd" version="3.1"> <enterprise-beans> <session> <ejb-name>TravelAgentEJB</ejb-name> <service-ref> <service-ref-name>service/ChargeItProcessorService</service-ref-name> <service-interface>com.charge_it.ProcessorService</service-interface> <wsdl-file>META-INF/wsdl/ChargeItProcessor.wsdl</wsdl-file> <jaxrpc-mapping-file>META-INF/mapping.xml</jaxrpc-mapping-file> <service-qname>chargeIt:ProcessorService</service-qname> <mapped-name>webservices/ProcessorService</mapped-name> <injection-target> <injection-target-class> com.titan.travelagent.TravelAgentBean</injection-target-class> <injection-target-name>processorService </ injection-target-name>

The <service-ref-name> element declares the name of the JAX-RPC service in the JNDI ENC it s always relative to the java:comp/env context. The <service-interface> element identifies the JAX-RPC service interface, which is implemented by a JAX-RPC service object. The <wsdl-file> identifies the location of the WSDL document that describes the Charge-It web service. The WSDL document must be packaged in the same EJB-JAR file as the EJB that is making the web service call, whether you are using a <service-ref> element or an annotation to inject your web service. The path is always relative to the root of the EJB-JAR file. In this case, a copy of the Charge-It WSDL document, ChargeItProcessor.wsdl, is stored in the META-INF directory of the EJBJAR file. The <jaxrpc-mapping-file> element identifies the location of the JAX-RPC mapping file relative to the root of the EJB-JAR file. In this case, it s also located in the META-INF directory. (The JAX-RPC mapping file is an additional deployment file that helps the EJB container to understand the mapping between the WSDL document and the service endpoint interfaces.) The <service-qname> element identifies the fully qualified XML name of the WSDL <service> definition to which this reference pertains. The qualified service name is relative to the WSDL document identified by the <wsdlfile> element. The <mapped-named> element is a vendor-specific identifier that can map to a global registry of the application server (usually the global JNDI). The <injectiontarget> element is used to tell the EJB container to inject an instance of ProcessorService into the processorService field of the TravelAgentBean class. You can find more information about using <injection-target> in 16.

A JAX-RPC service or client in a Java EE environment must have a JAX-RPC mapping file. The mapping file format is defined in the Implementing Enterprise Web Services (JSR-109) specification. There are many possible ways to map or bind Java to WSDL, and WSDL to Java. This can cause portability problems between different JAX-RPC implementations, since they may bind Java and WSDL in different ways. The JAX-RPC mapping file addresses this problem by configuring the specific details for how binding is supposed to occur. This allows for a service and a client to be portable across different Java EE implementations. The mapping file for the ChargeItProcessor.wsdl document follows:

< xml version='1.0' encoding='UTF-8' > <java-wsdl-mapping xmlns="http://java.sun.com/xml/ns/j2ee" xmlns:chargeIt="http://charge-it.com/Processor" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:xsd="http://www.w3.org/2001/XMLSchema"

xsi:schemaLocation="http://java.sun.com/xml/ns/j2ee http://www.ibm.com/webservices/xsd/j2ee_jaxrpc_mapping_1_1.xsd" version="1.1"> <package-mapping> <package-type>com.charge_it</package-type> <namespaceURI>http://charge-it.com/Processor</namespaceURI> </package-mapping> <service-interface-mapping> <service-interface>com.charge_it.ProcessorService</service-interface> <wsdl-service-name>chargeIt:ProcessorService</wsdl-service-name> <port-mapping> <port-name>chargeIt:ProcessorPort</port-name> <java-port-name>ProcessorPort</java-port-name> </port-mapping> </service-interface-mapping> <service-endpoint-interface-mapping> <service-endpoint-interface>com.charge_it.Processor </service-endpoint-interface> <wsdl-port-type>chargeIt:Processor</wsdl-port-type> <wsdl-binding>chargeIt:ProcessorSoapBinding</wsdl-binding> <service-endpoint-method-mapping> <java-method-name>charge</java-method-name> <wsdl-operation>chargeIt:charge</wsdl-operation> <method-param-parts-mapping> <param-position>0</param-position> <param-type>java.lang.String</param-type> <wsdl-message-mapping> <wsdl-message>chargeIt:chargeRequest</wsdl-message> <wsdl-message-part-name>name</wsdl-message-part-name> <parameter-mode>IN</parameter-mode> </wsdl-message-mapping> </method-param-parts-mapping> <method-param-parts-mapping> <param-position>1</param-position> <param-type>java.lang.String</param-type> <wsdl-message-mapping> <wsdl-message>chargeIt:chargeRequest</wsdl-message> <wsdl-message-part-name>number</wsdl-message-part-name> <parameter-mode>IN</parameter-mode> </wsdl-message-mapping> </method-param-parts-mapping> <method-param-parts-mapping> <param-position>2</param-position> <param-type>java.util.Calendar</param-type> <wsdl-message-mapping> <wsdl-message>chargeIt:chargeRequest</wsdl-message> <wsdl-message-part-name>exp-date</wsdl-message-part-name> <parameter-mode>IN</parameter-mode> </wsdl-message-mapping> </method-param-parts-mapping> <method-param-parts-mapping> <param-position>3</param-position> <param-type>java.lang.String</param-type> <wsdl-message-mapping>

<wsdl-message>chargeIt:chargeRequest</wsdl-message> <wsdl-message-part-name>card-type</wsdl-message-part-name> <parameter-mode>IN</parameter-mode> </wsdl-message-mapping> </method-param-parts-mapping> <method-param-parts-mapping> <param-position>4</param-position> <param-type>float</param-type> <wsdl-message-mapping> <wsdl-message>chargeIt:chargeRequest</wsdl-message> <wsdl-message-part-name>amount</wsdl-message-part-name> <parameter-mode>IN</parameter-mode> </wsdl-message-mapping> </method-param-parts-mapping> <wsdl-return-value-mapping> <method-return-value>int</method-return-value> <wsdl-message>chargeIt:chargeResponse</wsdl-message> <wsdl-message-part-name>return</wsdl-message-part-name> </wsdl-return-value-mapping> </service-endpoint-method-mapping> </service-endpoint-interface-mapping> </java-wsdl-mapping>

As you can see, the service interface is mapped to a WSDL <service> element, the endpoint interface is mapped to a WSDL <portType>, each method is mapped to a WSDL <operation>, and every parameter and return value is mapped to a specific WSDL <part> of a specific WSDL <message> definition. The complete JAX-RPC mapping file is too complicated to discuss in detail. Don t worry, though; you normally don t write these by hand. A Java EE implementation will provide tools to generate these files for you. Also, the JAX-RPC mapping file is no longer used in JAX-WS. We will discuss how it handles binding in the section Using JAX-WS on page 396.