package ejava.examples.ejbwar.inventory.bo;
   
   import java.io.InputStream;
   import java.io.Serializable;
   import java.io.StringWriter;
   
   import javax.persistence.Column;
   import javax.persistence.MappedSuperclass;
   import javax.persistence.Version;
  import javax.xml.bind.JAXBContext;
  import javax.xml.bind.JAXBException;
  import javax.xml.bind.Marshaller;
  import javax.xml.bind.Unmarshaller;
  import javax.xml.bind.annotation.XmlAttribute;
  
  /**
   * This class provides base definition and helper methods for representations
   * within the inventory domain.
   */
  @SuppressWarnings("serial")
  @MappedSuperclass
  public abstract class InventoryRepresentation implements Serializable {
  	public static final String NAMESPACE = "http://webejb.ejava.info/inventory";
  	
  	@Version
  	@Column(name="VERSION")
  	private int version;
  	
  	/**
  	 * This property is added to each entity so that we can have better 
  	 * control over concurrent updates
  	 * @return
  	 */
  	@XmlAttribute(required=true)
  	public int getVersion() { return version; }
  	public void setVersion(int version) {
  		this.version = version;
  	}
  	
  	/**
  	 * Our toString() implementation will take advantage of the JAXB defintion
  	 * for the class and marshall the object as an XML string.
  	 */
  	@Override
  	public String toString() {
  		try {
  			JAXBContext jbx = JAXBContext.newInstance(getClass());
  			Marshaller marshaller = jbx.createMarshaller();
  			marshaller.setProperty(Marshaller.JAXB_FORMATTED_OUTPUT, true);
  			StringWriter writer = new StringWriter();
  			marshaller.marshal(this, writer);
  			return writer.toString();
  		} catch (JAXBException ex) {
  			throw new RuntimeException("unexpected JAXB error marshalling object:", ex);
  		}
  	}
  	
  	/**
  	 * This method will unmarshall the specified class from the provided 
  	 * XML input stream.
  	 * @param clazz
  	 * @param is
  	 * @return
  	 */
  	@SuppressWarnings("unchecked")
  	public static <T> T unmarshall(Class<T> clazz, InputStream is) {
  		try {
  			JAXBContext jbx = JAXBContext.newInstance(clazz);
  			Unmarshaller marshaller = jbx.createUnmarshaller();
  			return (T) marshaller.unmarshal(is);
  		} catch (JAXBException ex) {
  			throw new RuntimeException("unexpected JAXB error marshalling object:", ex);
  		}
  	}
  }