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C.2. A service unit project

Overview

Each service unit in the service assembly must be its own project. These projects are placed at the same level as the service assembly project. The contents of a service unit's project depends on the component at which the service unit is targeted. At the minimum, a service unit project contains a POM and an XML configuration file.

Seeding a project using a Maven artifact

Red Hat JBoss Fuse provides Maven artifacts for a number of service unit types. They can be used to seed a project with the smx-arch command. As shown in Example C.3, the smx-arch command takes three arguments. The groupId value and the artifactId values correspond to the project's group ID and artifact ID.

Example C.3. Maven archetype command for service units

smx-arch su suArchetypeName [ "-DgroupId=my.group.id" ] [ "-DartifactId=my.artifact.id" ]

Important
The double quotes(") are required when using the -DgroupId argument and the -DartifactId argument.
The suArchetypeName specifies the type of service unit to seed. Table C.1 lists the possible values and describes what type of project is seeded.

Table C.1. Service unit archetypes

NameDescription
camelCreates a project for using the Apache Camel service engine
cxf-seCreates a project for developing a Java-first service using the Apache CXF service engine
cxf-se-wsdl-firstCreates a project for developing a WSDL-first service using the Apache CXF service engine
cxf-bcCreates an endpoint project targeted at the Apache CXF binding component
http-consumerCreates a consumer endpoint project targeted at the HTTP binding component
http-providerCreates a provider endpoint project targeted at the HTTP binding component
jms-consumerCreates a consumer endpoint project targeted at the JMS binding component (see Using the JMS Binding Component)
jms-providerCreates a provider endpoint project targeted at the JMS binding component (see Using the JMS Binding Component)
file-pollerCreates a polling (consumer) endpoint project targeted at the file binding component (see chapter "Using Poller Endpoints" in "Using the File Binding Component")
file-senderCreates a sender (provider) endpoint project targeted at the file binding component (see chapter "Using Sender Endpoints" in "Using the File Binding Component")
ftp-pollerCreates a polling (consumer) endpoint project targeted at the FTP binding component
ftp-senderCreates a sender (provider) endpoint project targeted at the FTP binding component
jsr181-annotatedCreates a project for developing an annotated Java service to be run by the JSR181 service engine [a]
jsr181-wsdl-firstCreates a project for developing a WSDL generated Java service to be run by the JSR181 service engine [a]
saxon-xqueryCreates a project for executing xquery statements using the Saxon service engine
saxon-xsltCreates a project for executing XSLT scripts using the Saxon service engine
eipCreates a project for using the EIP service engine. [b]
lwcontainerCreates a project for deploying functionality into the lightweight container [c]
beanCreates a project for deploying a POJO to be executed by the bean service engine
odeCreate a project for deploying a BPEL process into the ODE service engine
[a] The JSR181 has been deprecated. The Apache CXF service engine has superseded it.
[b] The EIP service engine has been deprecated. The Apache Camel service engine has superseded it.
[c] The lightweight container has been deprecated.

Contents of a project

The contents of your service unit project change from service unit to service unit. Different components require different configuration. Some components, such as the Apache CXF service engine, require that you include Java classes.
At a minimum, a service unit project will contain two things:
  • a POM file that configures the JBI plug-in to create a service unit
  • an XML configuration file stored in src/main/resources
    For many of the components, the XML configuration file is called xbean.xml. The Apache Camel component uses a file called camel-context.xml.

Configuring the Maven plug-in

You configure the Maven plug-in to package the results of the project build as a service unit by changing the value of the project's packaging element to jbi-service-unit as shown in Example C.4.

Example C.4. Configuring the maven plug-in to build a service unit

<project ...>
  <modelVersion>4.0.0</modelVersion>

  ...
  <groupId>com.widgets.demo.cxf-wsdl-first</groupId>
  <artifactId>cxfse-wsdl-first-su</artifactId>
  <name>CXF WSDL Fisrt Demo :: SE Service Unit</name>
  <packaging>jbi-service-unit</packaging>
  ...
</project>

Specifying the target components

To correctly fill in the metadata required for packaging a service unit, the Maven plug-in must be told what component (or components) the service unit is targeting. If your service unit only has a single component dependency, you can specify it in one of two ways:
  • List the targeted component as a dependency
  • Add a componentName property specifying the targeted component
If your service unit has more than one component dependency, you must configure the project as follows:
  1. Add a componentName property specifying the targeted component.
  2. Add the remaining components to the list dependencies.
Example C.5 shows the configuration for a service unit targeting the Apache CXF binding component.

Example C.5. Specifying the target components for a service unit

...
<dependencies>
  <dependency>
    <groupId>org.apache.servicemix</groupId>
    <artifactId>servicemix-cxf-bc</artifactId>
    <version>3.3.1.0-fuse</version>[2]
  </dependency>
>/dependencies>
...
The advantage of using the Maven dependency mechanism is that it allows Maven to verify if the targeted component is deployed in the container. If one of the components is not deployed, Red Hat JBoss Fuse will not hold off deploying the service unit until all of the required components are deployed.
Tip
Typically, a message identifying the missing component(s) is written to the log.
If your service unit's targeted component is not available as a Maven artifact, you can specify the targeted component using the componentName element. This element is added to the standard Maven properties block and it specifies the name of a targeted component, as specified in Example C.6.

Example C.6. Specifying a target component for a service unit

...
<properties>
  <componentName>servicemix-bean</componentName>
</properties>
...
When you use the componentName element, Maven does not check to see if the component is installed, nor does it download the required component.

Example

Example C.7 shows the POM file for a project that is building a service unit targeted to the Apache CXF binding component.

Example C.7. POM file for a service unit project

<project xmlns="http://maven.apache.org/POM/4.0.0"
         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0
                             http://maven.apache.org/maven-v4_0_0.xsd">

    <modelVersion>4.0.0</modelVersion>

    <parent> 1
        <groupId>com.widgets.demo</groupId>
        <artifactId>cxf-wsdl-first</artifactId>
        <version>1.0</version>
    </parent>

  <groupId>com.widgets.demo.cxf-wsdl-first</groupId>
  <artifactId>cxfse-wsdl-first-su</artifactId>
  <name>CXF WSDL Fisrt Demo :: SE Service Unit</name>
  <packaging>jbi-service-unit</packaging> 2

  <dependencies> 3
    <dependency>
      <groupId>org.apache.servicemix</groupId>
      <artifactId>servicemix-cxf-bc</artifactId>
      <version>3.3.1.0-fuse</version>
    </dependency>
  >/dependencies>

  <build>
    <plugins>
      <plugin> 4
        <groupId>org.apache.servicemix.tooling</groupId>
        <artifactId>jbi-maven-plugin</artifactId>
        <extensions>true</extensions>
      </plugin>
    </plugins>
  </build>
</project>
The POM file in Example C.7, “POM file for a service unit project” does the following:
1
Specifies that it is a part of the top-level project shown in Example C.2, “Top-level POM for a Red Hat JBoss Fuse JBI project”
2
Specifies that this project builds a service unit
3
Specifies that the service unit targets the Apache CXF binding component
4
Specifies to use the Red Hat JBoss Fuse Maven plug-in

[2] You replace this with the version of Apache CXF you are using.