[Tapestry Wiki] Update of "JEE-Annotation" by LennyPrimak

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The "JEE-Annotation" page has been changed by LennyPrimak:
http://wiki.apache.org/tapestry/JEE-Annotation

New page:
= How to make @EJB Annotation work in Tapestry pages and components =

This works on Tapestry 5.3 or higher.

== In your AppModule.java file, add the following method ==


{{{
    @Contribute(ComponentClassTransformWorker2.class)
    @Primary
    public static void provideClassTransformWorkers(OrderedConfiguration<ComponentClassTransformWorker2> configuration)
    {
        configuration.addInstance("EJB", EJBAnnotationWorker.class, "before:Property");
    }

}}}

== EJBAnnotationWorker.java ==

(add this to one of your non-tapestry packages)

{{{

/**
 * Inject an EJB into tapestry sources
 * 
 * @author Magnus
 * Enhancements by Lenny Primak
 */
public class EJBAnnotationWorker implements ComponentClassTransformWorker2
{
    @Override
    @SneakyThrows(NamingException.class)
    public void transform(PlasticClass plasticClass,
            TransformationSupport support, MutableComponentModel model)
    {
        for (PlasticField field : plasticClass.getFieldsWithAnnotation(EJB.class))
        {
            final EJB annotation = field.getAnnotation(EJB.class);
            String fieldType = field.getTypeName();
            String lookupname = null;

            //try lookup
            if (!isBlankOrNull(annotation.lookup()))
            {
                lookupname = annotation.lookup();
            } //try name
            else if(!isBlankOrNull(annotation.name()))
            {
                lookupname = annotation.name();
            }
            else if(!isBlankOrNull(annotation.beanName()))
            {
                lookupname = annotation.beanName();
            }

            //use type
            if (lookupname == null)
            {
                lookupname = guessByType(fieldType);
            }

            lookupname = prependPortableName(lookupname);

            Object injectionValue = locator.getJNDIObject(lookupname);

            if (injectionValue != null)
            {
                field.inject(injectionValue);
                field.claim(annotation);
            }
        }
    }
    
    
    public static String guessByType(String type) 
    {
        String lookupname = type.substring(type.lastIndexOf(".") + 1);
        // support naming convention that strips Local/Remote from the
        // end of an interface class to try to determine the actual bean name,
        // to avoid @EJB(beanName="myBeanName"), and just use plain old @EJB
        String uc = lookupname.toUpperCase();
        if (uc.endsWith(LOCAL) || uc.endsWith(REMOTE)) {
            lookupname = StripLocalPattern.matcher(lookupname).replaceFirst("");
        }
        return lookupname;
    }
    
    
    public static String prependPortableName(String lookupname)
    {
        //convert to jndi name
        if (!lookupname.startsWith("java:")) 
        {
            lookupname = "java:module/" + lookupname;
        }
        return lookupname;
    }
    

    private boolean isBlankOrNull(String s)
    {
        return s == null || s.trim().equals("");
    }
    

    private final JNDIObjectLocator locator = new JNDIObjectLocator();
    private static final String REMOTE = "REMOTE";
    private static final String LOCAL = "LOCAL";
    public static final Pattern StripLocalPattern = Pattern.compile(LOCAL + "|" + REMOTE, Pattern.CASE_INSENSITIVE);
}


}}}

== Using @EJB in your client code ==

{{{

class SomeTapestryPage
{
  @EJB private MyStatelessBeanLocal localBean;
}

}}}

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