import javax.jdo.annotations.Extension; //导入依赖的package包/类
/**
 * Obtiene el estado de una comanda
 * @return estado IEstadoComanda
 */
@Hidden
@Title(prepend = "Comanda ")
@Persistent(extensions = {
		@Extension(vendorName = "datanucleus", key = "mapping-strategy", value = "per-implementation"),
		@Extension(vendorName = "datanucleus", key = "implementation-classes", value = "dom.comanda.estado.NoConfirmada"
				+ ",dom.comanda.estado.EnEspera"
				+ ",dom.comanda.estado.EnPreparacion"
				+ ",dom.comanda.estado.Preparada") }, columns = {
		@Column(name = "idNoConfirmada"), @Column(name = "idEnEspera"),
		@Column(name = "idEnPreparacion"), @Column(name = "idPreparada") }, dependent = "true")
@MemberOrder(sequence = "2")
@Column(allowsNull = "false")
public IEstadoComanda getEstado() {
	return estado;
}
 

import javax.jdo.annotations.Extension; //导入依赖的package包/类
private void addVersioningMetadata(ClassMetadata cmd, Class<?> definition) {
    Class<Version> ann = ReflectionsUtil.getAnnotationClass(definition, Version.class);
    Version versionAnnotation = AnnotationUtils.findAnnotation(definition, ann);

    if (versionAnnotation != null) {
        VersionMetadata vmd = cmd.newVersionMetadata();
        vmd.setColumn(versionAnnotation.column());
        vmd.setStrategy(versionAnnotation.strategy());
        if (versionAnnotation.extensions().length == 0 || !"field-name".equals(versionAnnotation.extensions()[0].key())) {
            throw new MdsException(String.format("Cannot create metadata fo %s. Extension not found in @Version annotation.", cmd.getName()));
        }
        Extension extension = versionAnnotation.extensions()[0];
        vmd.newExtensionMetadata(DATANUCLEUS, "field-name", extension.value());
    }
}