package ejava.examples.ejbwar.inventory.rs;
   
   import java.io.IOException;
   
   import java.io.OutputStream;
   import java.lang.annotation.Annotation;
   import java.lang.reflect.Type;
   
   import javax.ws.rs.Produces;
  import javax.ws.rs.WebApplicationException;
  import javax.ws.rs.core.Context;
  import javax.ws.rs.core.MediaType;
  import javax.ws.rs.core.MultivaluedMap;
  import javax.ws.rs.ext.ContextResolver;
  import javax.ws.rs.ext.MessageBodyWriter;
  import javax.ws.rs.ext.Provider;
  import javax.ws.rs.ext.Providers;
  import javax.xml.bind.JAXBContext;
  import javax.xml.bind.JAXBException;
  import javax.xml.bind.Marshaller;
  import javax.xml.bind.annotation.XmlRootElement;
  
  /**
   * Put this class in your JAX-RS application to have XML output formatted
   * so that it is easier to read.
   */
  @Provider
  @Produces(MediaType.APPLICATION_XML)
  public class PrettyPrinter implements MessageBodyWriter<Object> {
  
      @Context protected Providers providers;
  
      public long getSize(Object object, Class<?> type, Type genericType,
              Annotation[] methodAnnotations, MediaType mediaType) {
          return -1; //says we don't know
      }
  
      /**
       * Return true for any JAXB class
       */
      public boolean isWriteable(Class<?> type, Type genericType, 
              Annotation[] methodAnnotations, MediaType mediaType) {
          for(Class<?> clazz = type;clazz != null; clazz=clazz.getSuperclass()) {
              if (clazz.isAnnotationPresent(XmlRootElement.class)) {
                  return true;
              }
          }
          return false;
      }
  
      /**
       * Write the provided JAXB object using formatted output.
       */
      public void writeTo(Object object, Class<?> type, Type genericType,
              Annotation[] methodAnnotations, MediaType mediaType,
              MultivaluedMap<String, Object> httpHeaders, OutputStream os)
              throws IOException, WebApplicationException {
  
      	//get a JAXBContext that can marshall the JAXBObject
          JAXBContext ctx = null;
          ContextResolver<JAXBContext> resolver = 
              providers.getContextResolver(JAXBContext.class, MediaType.APPLICATION_XML_TYPE);
          if (resolver != null) {
              ctx = resolver.getContext(type);
          }
          
          //if none is found, try a default one
          if (ctx == null) {
              try { ctx = JAXBContext.newInstance(type); } 
              catch (JAXBException ex) {throw new RuntimeException("error creating ad-hoc jaxbContext", ex);}
          }
  
          //marshall the object to the provided stream
          try {
              Marshaller marshaller = ctx.createMarshaller();
              marshaller.setProperty(Marshaller.JAXB_FORMATTED_OUTPUT, true);
              marshaller.marshal(object, os);
              os.flush();
          } catch (JAXBException ex) {
              throw new RuntimeException("error marshalling XML", ex);
          } finally {}
      }
  }