Generic JSF entity converter [duplikat]

Używam JSF 2.0 Zobacz mapę:

@FacesConverter("entityConverter")
public class EntityConverter implements Converter {

private static final String key = "com.example.jsf.EntityConverter";
private static final String empty = "";

private Map<String, Object> getViewMap(FacesContext context) {
    Map<String, Object> viewMap = context.getViewRoot().getViewMap();
    @SuppressWarnings({ "unchecked", "rawtypes" })
    Map<String, Object> idMap = (Map) viewMap.get(key);
    if (idMap == null) {
        idMap = new HashMap<String, Object>();
        viewMap.put(key, idMap);
    }
    return idMap;
}

@Override
public Object getAsObject(FacesContext context, UIComponent c, String value) {
    if (value.isEmpty()) {
        return null;
    }
    return getViewMap(context).get(value);
}

@Override
public String getAsString(FacesContext context, UIComponent c, Object value) {
    if (value == null) {
        return empty;
    }
    String id = ((Persistent) value).getId().toString();
    getViewMap(context).put(id, value);
    return id;
}
}

Moje rozwiązanie jest następujące:

@ManagedBean
@SessionScoped
public class EntityConverterBuilderBean {
    private static Logger logger = LoggerFactory.getLogger(EntityConverterBuilderBean.class);
    @EJB
    private GenericDao dao;

    public GenericConverter createConverter(String entityClass) {
        return new GenericConverter(entityClass, dao);
    }


}

public class GenericConverter implements Converter {

    private Class clazz;
    private GenericDao dao;

    public GenericConverter(String clazz, Generic dao) {
        try {
            this.clazz = Class.forName(clazz);
            this.dao = dao;
        } catch (Exception e) {
            logger.error("cannot get class: " + clazz, e);
            throw new RuntimeException(e);
        }
    }

    public Object getAsObject(javax.faces.context.FacesContext facesContext, javax.faces.component.UIComponent uiComponent, java.lang.String s) {
        Object ret = null;

        if (!"".equals(s)) {
            Long id = new Long(s);
            ret = dao.findById(clazz, id);
        }

        return ret;
    }

    public String getAsString(javax.faces.context.FacesContext facesContext, javax.faces.component.UIComponent uiComponent, java.lang.Object o) {
        if (o != null) {
            return ((SimpleEntity) o).getId() + "";
        } else {
            return "";
        }
    }
}

I na stronach:

 <h:selectOneMenu id="x" value="#{controller.x}" 
      converter="#{entityConverterBuilderBean.createConverter('com.test.model.TestEntity')}">

Użyj powierzchni Seam, zapewnia klasę konwertera, która robi to, co chcesz.

Org.jboss.seam.twarze.nawrócenie.Konwerter

Chociaż jest to projekt JBoss, Seam 3 działa dobrze z Glassfish 3.1 i nowsze.

Http://seamframework.org/Seam3/FacesModule

Na 3.1 ma kilka dodatkowych zależności; zobacz http://blog.ringerc.id.au/2011/05/using-seam-3-with-glassfish-31.html

Spróbuj użyć powierzchni szwu z Seam 3.

@Named("DocTypeConverter")
public class DocumentTypeConverter implements Converter, Serializable {

    private static final long serialVersionUID = 1L;

    @Inject
    private DocumentTypeSessionEJB proDocTypeSb;

    @Override
    public Object getAsObject(FacesContext context, UIComponent component,
            String value) {
        DocumentType result = null;

        if (value != null && !value.trim().equals("")) {  
            try {  
                result = (DocumentType) proDocTypeSb.findById(DocumentType.class, value);
            } catch(Exception exception) {  
                throw new ConverterException(new FacesMessage(FacesMessage.SEVERITY_ERROR, "Conversion Error", "Not a valid value"));  
            }  
        }  

        return result;
    }

    @Override
    public String getAsString(FacesContext context, UIComponent component,
            Object value) {
        String result = null;
        if (value != null && value instanceof DocumentType){
            DocumentType docType = (DocumentType) value;
            result = docType.getId();
        }

        return result;
    }

}

Używam czegoś takiego:

@Named
public class EntityConverter implements Converter {

    @Inject
    private EntityManager entityManager;

    @Inject
    private ConversionService conversionService;

    @Override
    public Object getAsObject(FacesContext context, UIComponent component, String value) {
        Class<?> entityType = component.getValueExpression("value").getType(context.getELContext());
        Class<?> idType = this.entityManager.getMetamodel().entity(entityType).getIdType().getJavaType();
        Object id = this.conversionService.convert(idType, value);
        return this.entityManager.getReference(entityType, id); // find() is possible too
    }

    @Override
    public String getAsString(FacesContext context, UIComponent component, Object value) {
        Object id = this.entityManager.getEntityManagerFactory().getPersistenceUnitUtil().getIdentifier(value);
        return this.conversionService.convert(String.class, id);
    }   
}

ConversionService jest zdefiniowana w ten sposób (implementacja jest tutaj poza zakresem):

public interface ConversionService {

    <T> T convert(Class<T> targetType, Object source);
}

W szablonie użyj <f:converter binding="#{entityConverter}" />.

Aby uzupełnić odpowiedź Craiga Ringera, możesz użyć generycznego org.jboss.seam.faces.conversion.ObjectConverter z szwu 3 Fasesmodule .

Możesz pobrać kod tutaj : https://github.com/seam/faces/blob/develop/impl/src/main/java/org/jboss/seam/faces/conversion/ObjectConverter.java

Używa 2 HashMaps (jeden jest używany odwrotnie) i przechowuje swoje obiekty w Conversation.