/**
* Check whether a resource is valid. A valid resource must have a non-blank ID, a non-blank link
* and a media type.
*
* @param book the book the resource is for
* @param resource the resource to check
* @return whether the resource is valid
*/
private static boolean isValidResource(final Book book, final Resource resource) {
if (resource == null
|| (resource.getMediaType() == MediatypeService.NCX
&& book.getSpine().getTocResource() != null)) {
return false;
}
if (StringUtil.isBlank(resource.getId())) {
LOGGER.error(
"resource id must not be blank (href: "
+ resource.getHref()
+ ", mediatype:"
+ resource.getMediaType()
+ ")");
return false;
}
if (StringUtil.isBlank(resource.getHref())) {
LOGGER.error(
"resource href must not be blank (id: "
+ resource.getId()
+ ", mediatype:"
+ resource.getMediaType()
+ ")");
return false;
}
if (resource.getMediaType() == null) {
LOGGER.error(
"resource media type must be specified (id: "
+ resource.getId()
+ ", href:"
+ resource.getHref()
+ ")");
return false;
}
return true;
}
/**
* Write a resource as an item element.
*
* @param serializer the XML serialiser to write the item element to
* @param book the book to write the resource for
* @param resource the resource to write as an item element
* @throws IOException if an I/O error occurs
*/
private static void writeItem(
final XmlSerializer serializer, final Book book, final Resource resource) throws IOException {
if (!isValidResource(book, resource)) {
return;
}
serializer.startTag(NAMESPACE_OPF, OPFElements.ITEM);
serializer.attribute(PREFIX_EMPTY, OPFAttributes.ID, resource.getId());
serializer.attribute(PREFIX_EMPTY, OPFAttributes.HREF, resource.getHref());
serializer.attribute(PREFIX_EMPTY, OPFAttributes.MEDIA_TYPE, resource.getMediaType().getName());
if (StringUtil.isNotBlank(resource.getProperties())) {
serializer.attribute(PREFIX_EMPTY, OPFAttributes.PROPERTIES, resource.getProperties());
}
serializer.endTag(NAMESPACE_OPF, OPFElements.ITEM);
}