// Encode keys as strings on GAE to support entity group hierarchies
if (isGaeEnabled && identifierType.equals(JavaType.STRING)) {
AnnotationMetadataBuilder extensionBuilder = new AnnotationMetadataBuilder(
DATANUCLEUS_JPA_EXTENSION);
extensionBuilder.addStringAttribute("vendorName", "datanucleus");
extensionBuilder.addStringAttribute("key", "gae.encoded-pk");
extensionBuilder.addStringAttribute("value", "true");
annotations.add(extensionBuilder);
}
// Compute the column name, as required