/**
* Resolves a reference to a local element identified by address and identifier, where {@code
* linkBase} identifies a document, including the current document, and {@code linkRef} is the id
* of the desired element.
*
* <p>If {@code linkBase} refers to a local COLLADA file and {@code linkRef} is non-null, the
* return value is the element identified by {@code linkRef}. If {@code linkRef} is null, the
* return value is a parsed {@link ColladaRoot} for the COLLADA file identified by {@code
* linkBase}. Otherwise, {@code linkBase} is returned.
*
* @param linkBase the address of the document containing the requested element.
* @param linkRef the element's identifier.
* @return the requested element, or null if the element is not found.
* @throws IllegalArgumentException if the address is null.
*/
protected Object resolveLocalReference(String linkBase, String linkRef) {
if (linkBase == null) {
String message = Logging.getMessage("nullValue.DocumentSourceIsNull");
Logging.logger().severe(message);
throw new IllegalArgumentException(message);
}
try {
File file = new File(linkBase);
if (!file.exists()) return null;
// Determine whether the file is a COLLADA document. If not, just return the file path.
if (!WWIO.isContentType(file, ColladaConstants.COLLADA_MIME_TYPE))
return file.toURI().toString();
// Attempt to open and parse the COLLADA file.
ColladaRoot refRoot = ColladaRoot.createAndParse(file);
// An exception is thrown if parsing fails, so no need to check for null.
// Add the parsed file to the session cache so it doesn't have to be parsed again.
WorldWind.getSessionCache().put(linkBase, refRoot);
// Now check the newly opened COLLADA file for the referenced item, if a reference was
// specified.
if (linkRef != null) return refRoot.getItemByID(linkRef);
else return refRoot;
} catch (Exception e) {
String message =
Logging.getMessage("generic.UnableToResolveReference", linkBase + "/" + linkRef);
Logging.logger().warning(message);
return null;
}
}
