import java.lang.reflect.Method;
import java.lang.reflect.Modifier;
import org.apache.hivemind.ApplicationRuntimeException;
import org.apache.hivemind.Location;
import org.apache.hivemind.service.BodyBuilder;
import org.apache.hivemind.service.MethodSignature;
import org.apache.tapestry.Tapestry;    
  import org.apache.tapestry.annotations.AnnotationUtils;
import org.apache.tapestry.annotations.MethodAnnotationEnhancementWorker;    
  import org.apache.tapestry.engine.ILink;
import org.apache.tapestry.enhance.EnhancementOperation;
import org.apache.tapestry.spec.IComponentSpecification;

public class InjectExternalLinkAnnotationWorker implements           
     MethodAnnotationEnhancementWorker ...{
public void performEnhancement(EnhancementOperation op,IComponentSpecification spec, 
 Method method, Location location) ...{
if (!method.getReturnType().equals(ILink.class))
throw new ApplicationRuntimeException(
"injectExternalLink annotation must return ILink");                
 InjectExternalLink injectExternalLink = method.getAnnotation(InjectExternalLink.class);  
String pageName = injectExternalLink.value();
BodyBuilder builder = new BodyBuilder();
builder.begin();
Class[] parameterTypes = method.getParameterTypes();
int paramCount = Tapestry.size(parameterTypes);
if (paramCount > 0) ...{
if (parameterTypes[0].isArray()) ...{

builder.addln(
"return getPage().getRequestCycle().getInfrastructure().getServiceMap().getService(
     org.apache.tapestry.Tapestry.EXTERNAL_SERVICE).getLink(
     false, new org.apache.tapestry.engine.ExternalServiceParameter(\"{0}\",$1));"
         ,pageName);    
     } else ...{
builder.addln(
"java.lang.Object[] params = new java.lang.Object0}];",paramCount);
for (int i = 0; i < paramCount; i++) ...{
builder.add("params[{0}] = ", i);
if (parameterTypes[i].isPrimitive())
builder.add("($w) ");  // Parameter $0 is this, so $1 is the first real parameter.   
builder.addln("${0};", i + 1);
}
builder.addln(
"return getPage().getRequestCycle().getInfrastructure().getServiceMap().getService(
                org.apache.tapestry.Tapestry.EXTERNAL_SERVICE).getLink(false, 
             new org.apache.tapestry.engine.ExternalServiceParameter(\"{0}\",params));"
                  ,pageName);
     }           
   }
builder.end();
op.addMethod(Modifier.PUBLIC, new MethodSignature(method), builder.toString(),location);  
 if (isGetter(method))
op.claimReadonlyProperty(AnnotationUtils.getPropertyName(method));        }
boolean isGetter(Method method) ...{           
  return method.getName().startsWith("get")&& method.getParameterTypes().length == 0;
 }
 }  

<module id="your.model.annotation" version="1.0.0" package="your.package.annotations">

     <contribution configuration-id="tapestry.annotation.MethodWorkers">

      <worker annotation="InjectPageLink" 
           object="instance:InjectPageLinkAnnotationWorker"/>

      <worker annotation="InjectExternalLink" 
           object="instance:InjectExternalLinkAnnotationWorker"/>

    <!--</span-->contribution>

<!--</span-->module>